THE UNIV ERS IT Y OF MI C H I GAN COLLEGE OF ENGINEEERING Department of Civil Engineering Third Progress Report METEOROLOGICAL ANALYSIS E. Wendell, Hewson Professor of Meteorology Gerald C. Gill Associate Research Engineer Harold W. Baynton Research Associate UMRI Project 2515 under contract with: POWER REACTOR DEVELOPMENT COMPANY DETROIT, MICHIGAN administered by: THE UNIVERSITY OF MICHIGAN RESEARCH INSTITUTE ANN ARBOR February 1959

iPn r f- q k /%IsI

PREFACE The past two progress reports have discussed data through 31 May 1957~ The present report will add data up to 30 November 1957. For the sake of continuity and ease: of reference, it was decided to' include a year of data in this report. Therefore the data are presented by seasons and also in the form of a yearly summary. The past reports and the present one emphasize the special meteorological features resulting from the proximity of the plate site to Lake Erie. The lakebreeze circulation occurring at the plant site is discussed fully as is the effect of this circulation on the diffusion characteristicso The authors gratefully acknowledge the aid given by Messrs. Donald A. Blessing, Irwin Spickler, W. Gale Biggs, Merlin Zook, and Mrs. Katalin Racz in preparation of the tables; Mrs. Dolores Wells, and Messrs. Surinder S. Sidhu and Kuang T. Huang in abstraction of the data from the chart rolls; and Mr. Nobuhiro Yotsukura in drafting the figures. iii

TABLE OF CONTENTS Page LIST OF TABLES vi LIST OF FIGURES xii ABSTRACT xvi Io ANALYSIS OF TEMPERATURE-LAPSE-RATE DATA 1 1. Classification of Lapse-Rate Data 1 2. Frequency of Inversions and Seasonal Trends 1 3. Diurnal Variation of Inversions 3 4. The Persistence of Inversions 11 5. The Association of Lapse Rates with Wind Speed 13 60 The Association of Lapse Rates with Wind Direction 25 7. Summary 31 II. ANALYSIS OF WIND DATA 33 1. Introduction 33 2. Wind Directions at the Enrico Fermi Site 33 35 Wind Speed at the Enrico Fermi Site 67 III. LAND- AND LAKE-BREEZE EFFECTS AT LAGOONA BEACH 74 1. Introduction 74 2. Identifying the Phenomenon 75 3, Characteristics of Land and Lake Breezes 75 4. Lake-Breeze Effects at Lagoona Beach 75 5. Conclusions 79 IV. ANALYSIS OF PRECIPITATION DATA 82 1o Introduction 82 2. Seasonal Variations in Frequency of Precipitation 82 35 The Association of Wind Speed with Precipitation 103 4. The Association of Wind Direction with Precipitation 103 V. CONCLUSIONS 105 APPENDIX Ao A Method for Eliminating the Bias from Wind-Direction Frequency Statistics 107 APPENDIX B. The Force Which Generates Land and Lake Breezes 116 REFERENCES 11.8 v

LIST OF TABLES Table Page I Summary of Temperature-Lapse-Rate Data 25 to 100 ft at the Enrico Fermi Site by Seasons and Annual Summary, 1 December -1956 30 November 1957. 2 II Summary of Temperature-Lapse-Rate Data 20 to 300 ft at the WJBK-TV Tower, Detroit, Michigan, by Seasons and Annual Summary, 1 December 1956 - 50 November 1957o 2 III Percentage Frequency of Surface Based Inversions at Mount Clemens, Michigan, February 1948 - December 1950 and at Toledo, Ohio, January 1946 - December 1950 as Observed at 10 a m. and 10 p m. EST 3 IV Diurnal Variation of Inversion Frequency at WJBK-TV Tower During the Period 1 December 1956 - 30 November 1957. 4 TV Hourly Percentage Frequency of Inversions at the Enrico Fermi Site by Seasons and Annual Summary, 1 December 1956 - 30 November 1957 5 VI Frequency and Magnitude of Positive Temperature Anomalies by Months at Toledo, Ohio, During a Period of 7 Years. 12 VII The Frequency of Thermal Regimes Favorable for the Formation of Prolonged Inversions at the Enrico Fermi Site Shown as a Function of Mean Lake Temperatures at Monroe and Normal Air Temperatures at Toledoo 14 VIII Mean Wind Speeds Associated with Inversions and Noninversions at the Enrico Fermi Site~ Winter, 1956-1957. 15 IX Mean Wind, Speeds Associated with Inversions and Noninversions at the Enrico FermiSite. Spring, 1957o 17 X Mean Wind Speeds Associated with Inversions and Noninversions at the Enrico Fermi Site. Summer, 1957. 19 XI Mean Wind Speeds Associated with Inversions and Noninversions at the Enrico Fermi Site~ Fall, 1957. 21 XII Mean Wind Speeds Associated with Inversions and Noninversions at the Enrico Fermi Site~ Annual Summary, 1956-19 57. 23 vi

LIST OF TABLES (Continued) Table Page XIII The Association of Temperature-Lapse Rates with Wind Direction at the Enrico Fermi Site: Winter 1956-1957. XIV The Association of Temperature-Lapse Rates with Wind Direction at the Enrico Fermi Site: Spring, 1957. 27 XV The Association of Temperature-Lapse Rates with Wind Direction at the Enrico Fer-mi Site: Summer, 1957. 28 XVI The Association of Temperature-Lapse Rates with Wind Direction at the Enrico Fermi Site: Fall, 1957. 29 XVII The Association of Temperature-Lapse Rates with Wind Direction at the Enrico Fermi Site: Annual Summary, 1956-1957. 30 XVIII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Winter, 1956-1957, Enrico Fermi Site. 355 XIX Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Winter, 1956-1957, Toledo Express Airport. 36 XX Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Winter, 1956-1957, Detroit City Airport. 37 XXI Percentage Frequency of Occurrence of Winds in Various Directions - Biased and Unbiased: Winter, 19561957, Detroit City Airporto 38 XXII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Winter, 1950-1954, Toledo Municipal Airport. 39 XXIII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Spring, 1957, Enrico Fermi Site. 41 XXIV Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Spring, 1957, Toledo Express Airport. 4r vii

LIST OF TABLES (Continued) Table Page XXV Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds' Spring, 1957, Detroit City Airport. 43 XXVI Percentage Frequency of Occurrence of Winds in Various Directions - Biased and Unbiased~ Spring, 1957, Detroit City Airport. 44 XXVII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds~ Spring Seasons, 1950-1954, Toledo Municipal Airport. 45 XXVIII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind SpeedsSummer, 1957, Enrico Fermi Siteo 47 XXIX Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Summer, 1957, Toledo Express Airport. 48 XXX Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Summer, 1957, Detroit City Airport. 49 XXXI Percentage Frequency of Occurrence of Winds in Various Directions - Biased and Unbiased~ Summer, 1957, Detroit City Airport. 50 XXXII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Summer Seasons, 1950-1954, Toledo Municipal Airport. 51 XXXIII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Fall, 1957, Enrico Fermi Siteo 53 XXXIV Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Fall, 1957, Toledo Express Airporto 54 XXXV Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Fall, 1957, Detroit City Airport, 55 viii

LIST OF TABLES (Continued) Table Page XXXVI Percentage Frequency of Occurrence of Winds in Various Directions - Biased and Unbiased: Fall, 1957, Detroit City Airport. 56 XXXVII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Fall Seasons, 1950-1954, Toledo Municipal Airport. 57 XXXVIII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Annual Summary, 1956-1957, Enrico Fermi Site. 59 XXXIX Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Annual Summary, 1956-1957, Toledo Express Airport. 60 XL Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Annual Summary, 1956-1957, Detroit City Airport. 61 XLI Percentage Frequency of Occurrence of Winds in Various Directions - Biased and Unbiased: Annual Summary, 1956-1957, Detroit City Airport. 62 XLII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds: Five-Year Summary, 1950-1954, Toledo Municipal Airport. 65 XLIII Combined Percentage Frequency of Occurrence of Winds from the E, ESE, SE, SSE, and S. 1 December 1956 - 30 November 1957, at the Enrico Fermi Site, Toledo Express Airport, and Detroit City Airport, and 5-Year Average at Toledo Municipal Airport. 65 XLIV Combined Percentage Frequency of Occurrence of Winds from the W, WNW, NW, NNW, N, and NNE. 1 December 1956 - 30 November 1957, at the Enrico Fermi Site, Toledo Express Airport, and Detroit City Airport, and 5-Year Average at Toledo Municipal Airport. 66 ix

LIST OF TABLES (Continued) Table Page XLV Percentage Frequency of Occurrence of ENE Winds, 1 December 1956 - 30 November 1957, at the Enrico Fermi Site, Toledo Express Airport, and Detroit City Airport, and 5-Year Average at Toledo Municipal Airport, 66 XLVI Percentage Frequency of Occurrence of SSW Winds, 1 December 1956 - 30 November 1957, at the Enrico Fermi Site, Toledo Express Airport, and Detroit City Airport, and 5-Year Average at Toledo Municipal Airport. 66 XLVII Percentage Frequency of Occurrence of SW and WSW Winds, 1 December 1956 - 30 November 1957^ at the Enrico Fermi Site, Toledo Express Airport, and Detroit City Airport, and 5-Year Average at Toledo Municipal Airport. 67 XLVIII The Association of Precipitation with Wind at the Enrico Fermi Site: Winter, 1956-1957. 83 XLIX The Association of Precipitation with Wind at the Toledo Express Airport: Winter, 1956-1957. 84 L The Association of Precipitation with Wind at Toledo Municipal Airport: Winter Seasons, 1950-1954. 85 LI The Association of Precipitation with Wind at the Enrico Fermi Site: Spring, 1957o 87 LII The Association of Precipitation with Wind at the Toledo Express Airport: Spring, 1957. 88 LIII The Association of Precipitation with Wind at Toledo Municipal Airport: Spring Seasons, 1950-1954. 89 LIV The Association of Precipitation with Wind at the Enrico Fermi Site: Summer, 1957o 91 LV The Association of Precipitation with Wind at the Toledo Express Airport: Summer, 1957. 92 LVI The Association of Precipitation with Wind at the Toledo Municipal Airport: Summer Seasons, 1950-1954o 93 x

LIST OF TABLES (Concluded) Table Page LVII The Association of Precipitation with Wind at the Enrico Fermi Site: Fall, 1957. 95 LVIII The Association of Precipitation with Wind at the Toledo Express Airport: Fall, 1957. 96 LIX The Association of Precipitation with Wind at the Toledo Municipal Airport, Fall Seasons, 1950-1954. 97 LX The Association of Precipitation with Wind at the Enrico Fermi Site: Annual Summary, 1956-1957. 99 LXI The Association of Precipitation with Wind at the Toledo Express Airport, Annual Summary, 1956-1957o 100 LXII The Association of Precipitation with Wind at the Toledo Municipal Airport: Five-Year Summary, 1950-1954. 101 LXIII A Comparison of Relative Frequency of Measurable Precipitation at the Enrico Fermi Site and Toledo Express Airport, 1 December 1956 - 30 Novenmber 1957 and Toledo Municipal Airport, 1 January 1950 - 31 December 1954. 103 LXIV Computations of X2 from City A Records. 108 LXV Reported Wind Occurrences and Computed Occurrences with Bias Removed (Method 1) for the Period 1 October 1956 - 30 November 1956, City A. 110 LXVI Reported Wind Occurrences and Computed Occurrences with Bias Removed (Method 2) for the Period 1 October 1956 - 30 November 1956, City A. 112 LXVII Frequency of Occurrence of Winds from Various Directions as Reported and as Computed by Two Methods for Removing the Bias for the Period 12 October 1956 - 30 November 1956, City B. 114 xi

LIST OF FIGURES Figure Page 1 Diurnal variation of inversions at the Enrico Fermi site and at WJBK-TV tower: Winter, 1956-1957. 6 2 Dilurnal variation of inversions at the Enrico Fermi site and at WJBK-TV tower: Spring, 1957, 7 3 Diurnal variation of inversions at the Enrico Fermi site and at WJBK-TV tower: Summer, 1957 8 4 Diurnal variation of inversions at the Enrico Fermi site and at WJBK-TV tower: Fall, 1957. 9 5 Diurnal variation of inversions at the Enrico Fermi site and at WJBK-TV tower: Annual Summary, 1956-1957. 10 6 Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Winter, 195619577 16 7 Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Spring, 1957. 18 8 Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Summer, 1957. 20 9 Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Fall, 1957. 22 10 Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Annual Summary, 1956-1957o 24 11 Frequency of inversions associated with wind direction for the Enrico Fermi site for all seasons and annual summary, 1956-1957~ 32 xii

LIST OF FIGURES (Continued) Figure Page 12 Topographic map of site and surroundings. 34 13 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Winter Seasons, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Winter, 1956-1957. 40 14 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Spring Seasons, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Spring, 1957. 46 15 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Summer Seasons, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Summer, 1957. 52 16 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Fall Seasons, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Fall, 1957. 58 17 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Five-Year Summary, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Annual Summary, 1956-1957. 64 18 Mean wind speed at the Enrico Fermi site and DetroitToledo combined, for 16 directions, expressed as a percentage of the overall mean winter wind speed, 1956-1957. 68 19 Mean wind speed at the Enrico Fermi site and DetroitToledo combined, for 16 directions, expressed as a percentage of the overall mean spring wind speed, 1957. 69 20 Mean wind speed at the Enrico Fermi site and DetroitToledo combined, for 16 directions, expressed as a percentage of the overall mean summer wind speed, 1957. 70 xiii

LIST OF FIGURES (Continued) Figure Page 21 Mean wind speed at the Enrico Fermi site and DetroitToledo combined, for 16 directions, expressed as a percentage of the overall mean fall wind speed, 1957. 71 22 Mean wind speed at the Enrico Fermi site and DetroitToledo combined, for 16 directions, expressed as a percentage of the overall mean annual wind speed, 1956-1957. 72 25 Mean pressure map of Great Lakes area for 23 selected lake-breeze days. 77 24 Three hourly windroses for 23 selected lake-breeze days at the Enrico Fermi siteo 78 25 Percentage frequency of diurnal lake breeze, ESE, SE, and SSE and diurnal land breeze, W, WNW, and NW and diurnal temperatures in OF at Monroe and Toledo for 25 selected lake-breeze days. 80 26 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Winter Seasons, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Winter, 1956-1957. 86 27 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Spring Seasons, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Spring, 19570 90 28 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Summer Seasons, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Summer, 1957. 94 29 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Fall Seasons, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Fall, 1957o 98 xiv

LIST OF FIGURES (Concluded) Figure Page 30 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Five-Year Summary, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Annual Summary, 1956-1957. 102 31 Comparison of relative frequencies of wind at City B, USA, as reported and as computed by the two methods for removing bias, 12 October - 30 November 1956. 115 32 Schematic diagram of lake-breeze circulation. 117 xv

ABSTRACT Temperature-lapse-rate data are classified according to' their importance in relation to air-pollution characteristicso The frequency of inversions, seasonal trends, diurnal variation, and persistence of inversions are discussedo Lapse rates and their association with wind speed and wind direction are examinedo Wind directions and wind speeds at the Enrico Fermi plant site are analyzed so as to bring out the differences between them and those observed at Detroit City Airport and Toledo Express Airporto A definite lake breeze at Lagoona Beach is identified and characterized and its effects are showno Seasonal variations in the frequency of precipitation and the association of wind speed and direction with precipitation are discussedo A method for eliminating the bias from wind-direction frequency statistics is presented in the Appendix along with a discussion of the force which generates land and lake breezeso xvi

I. ANALYSIS OF TEMPERATURE-LAPSE-RATE DATA 1o CLASSIFICATION OF LAPSE-RATE DATA Temperature-lapse rates at the plant site are obtained from the difference between the temperatures at heights of 25 and 100 ft on the meteorological tower. This represents a relatively thin slice of the layer that is important in studies of turbulence and diffusion. Moreover, the lapse rate in this 75-ft slice is likely to differ substantially in magnitude if not in characteristic from that of the lower few hundred feet, taken as a whole. For these reasons, the practice initiated in the second progress report of simply classifying lapse rates as strong, weak, or inversion has been continued. Strong lapse rates are those which exceed the dry adiabatic lapse rate; weak lapse rates are intermediate between dry adiabatic and isothermal lapse rates; all cases in which temperatures increase with height are inversions. The implications of each lapse-rate classification in diffusion were outlined in the second progress report and are repeated here. Generally speaking, strong lapse rates, weak lapse rates, and inversions are associated with above average, average, and below average diffusion conditions, respectively. In the present report the investigation of the inversion climatology at the plant site is extended through the summer and fall of 1957. Lapse-rate data for the WJBK-TV tower continue to be available, so that comparisons between the two installations are again included. Annual summaries are included with most of the tables and charts. The analysis continues to lay stress on any evidence that there are lake influences present at the plant site which result in a climatology different from that of inland locations. 2. FREQUENCY OF INVERSIONS AND SEASONAL TRENDS From the hourly record of lapse rates at the plant site it is possible to compute the relative frequency of inversions, strong lapse, and weak lapse rates in the layer of from 25 to 100 fto This has been done for each season of the first full year of operation at the plant site. The results are presented in Table I together with an annual summary. Although lapse-rate data at the WJBK-TV tower are abstracted and summarized in a somewhat different manner, they still provide a seasonal breakdown of relative frequencies of inversion in the layer of from 20 to 300 ft. These are presented in Table II. 1

TABLE I SUMMARY OF TEMPERATURE-LAPSE-RATE DATA 25 TO 100 FT AT THE ENRICO FERMI SITE BY SEASONS AND ANNUAL SUMMARY 1 December 1956 5 30 November 1957 Winter Spring Summer Fall Annual Total hours 2160 2208 2208 2184 8760 Number missing hours 404 70 715 681 1870 Number hourly observations 1756 2138 1493 1503 6890 Percent missing data 18.7% 35,2 32.4% 31.2% 215 3% Percent inversions 21.4 18o6 19o 3 17.4 19o2 Percent strong lapse 46,3 71.3 68.9 7601 65o5 Percent weak lapse 32.3 10.1 11.8 6o5 1553 100.0%o 100 l o 100 lOo % 100 00 100. P0 TABLE II SUMMARY OF TEMPERATURE-LAPSE -RATE DATA 20 TO 300 FT AT THE WJBK-TV TOWER, DETROIT, MICHIGAN BY SEASONS AND ANNUAL SUMMARY 1 December 1956 - 30 November 1957 Winter Spring Summer Fall Annual Total hours 2160 2208 2208 2184 8760 Number missing hours 664 426 824 112 2026 Number hourly observations 1496 1782 1384 2072 6734 Percent missing data 30.7% 195o% 57.53 5l1% 235l1 Number hours inversion 392 388 569 834 2096 Percent inversions 26.3 21.8%o 41. % 38 1% 315o1% 2

The most striking difference between the two sites is the greater frequency of inversions at the WJBK-TV tower, a feature that is present in each season, but one which is particularly noticeable in the fallo The seasonal variation of inversion frequency provides another basis for differentiation, From winter through summer the seasonal variations at the two sites appear to be in phase; then in the fall the frequency at WJBK-TV remains high whereas that at the plant site falls to a minimumo Of the two records, that for WJBK-TV is more or less consistent with what is usually considered to be the frequency and the seasonal variation of inversion frequency in this area, It will be well to await further data before attempting to account for or interpret the differences that have appeared in the first year. Insofar as the WJBK-TV tower'is concerned, it is known that most of the inversion hours occur at night (see Section 3) as the result of the c the result of the cooling of the ground The ituation at the plant site is quite different since the lapse rates are measured within a few feet of the lake surface which does not cool appreciably at nighto Hence, whenever winds are off the water, there will be little tendency for nocturnal inversions to form. This could lead to a greater frequency of inversions at the WJBK-TV tower. The difference in the seasonal frequency of inversions is less easy to account for and no attempt will be made to do so until the apparent anomaly at the plant site is confirmed by additional datao However, the following section sheds some additional light on the infrequency of inversions at the plant site during the fall seasono 35 DIURNAL VARIATION OF INVERSIONS The diurnal variation of inversions at inland stations is well documented Since inversions form readily at night, they are most frequent during the night and least frequent during the day. A study of radiosoundings taken at Moint Clemens, Michigan, and Toledo, Ohio,l showed that inversions were much more frequent at 10 pom. than 10 aomo Eastern Standard Time. Some of the results are presented in Table IIIo TABLE III PERCENTAGE FREQUENCY OF SURFACE BASED INVERSIONS AT MOUNT CLEMENS, MICHIGAN, FEBRUARY 1948 - DECEMBER 1950 AND AT TOLEDO, OHIO, JANUARY 1946 - DECEMBER 1950 AS OBSERVED AT 10 A.M AND 10 PeMo EASTERN STANDARD TIME Station Time Winter Spring Summer Fall Annual Mto Clemens 10 ao.m 81l 700 208 702 602 10 pomo 2505 45,7 6Lo5 5603 4702 Toledo 10 aomo 13o8 357 0o5 4o6 596 10 pomo 3806 49ol 72o6 67o3 5609 5

The diurnal variation of inversions at the WJBK-TV tower during the 12 months ending November 30, 1957, is in good agreement with the accepted diurnal variationo The diurnal variation of inversions at WJBK-TV is shown in Table TVo TABLE IV DIURNAL VARIATION IN PERCENT OF INVERSION FREQUENCY AT WJBK-TV TOWER DURING THE PERIOD 1 DECEMBER 1956 - 30 NOVEMBER 1957 6 hours Winter Spring Summer Fall Annual ending at 0600 412 46.1 77.5 59~5 5596 1200 22~5 15.3 5330 3359 26.2 1800 4o6 2o7 6o5 9o3 5.9 2400 3605 24,9 45.9 58.2 42,0 The diurnal variation of inversions at the plant site has now been examined for the first full year of operationo The results appear in Table V for each of the seasons and an annual summary. The same data plus those of Table IV are presented graphically in FigSo 1-5. The difference between the two locations is quite striking. Instead of the nighttime maximum and daytime minimum which characterizes the WJBK-TV tower data, two maxima and two minima occur at the Enrico Fermi site. The nighttime maximum is still present, with a decreasing frequency in the early daylight hours. About mid-afternoon the frequency rises to a second maximum of the same order of magnitude as the first but of shorter duration. There is a second minimum which occurs about the last hour of daylight, and then the frequency starts to rise again as the effects of nighttime cooling begin to show upo The afternoon maximum is evidence of a process or mechanism at the Enrico Fermi site that is not present at the WJBK-TV towero In an attempt to identify the mechanism causing these frequent afternoon inversions. the data comprising Table V were examined month by month. On 13 afternoons in June and 10 in July, inversions occurredo Afternoon inversions occurred in all months except October. It is this complete absence of afternoon inversions in October that is chiefly responsible for the infrequency of inversions during the fallo The 23 summer occurrences of afternoon inversions were examined in more detail and proved to be the result of the well-known lakebreeze effect. With the identification of the lake breeze as a primary factor in the inversion climatology of the Enrico Fermi site, an extensive investigation of the characteristics of the lake breeze has been undertaken and is described separately in Part III of this report. 4

TABLE V HOURLY PERCET,'TAGE FREQUJENCY OF'''.INVER.SIONS AT THE' ENRICO: FERMI SITE BY SEASONS AND ANNUAL SUMMARY 1 December 1956 - 50 November 1957 Hour nHour Winter Spring Summer Fall Annual Ending 0100 25.7 20.0 18.0 26.2 22.4 0200 24.3 20.0 19.7 31.3 23.4 0300 23.0 20.0 24.6 23.1 22.4 0400 23.3 25.8 21.7 17.2 22.4 0500 24.7 20.2 25,0 22.6 22.9 0600 25.0 20.5 28.9 21.0 23.5 0700 22.5 19o5 19.6 25.8 21.7 0800 21.4 17.2 9.1 19.4 17.2 0900 22.2 11.1 6.5 1.6.9 17.6 1000 11.1 1355 13.4 10.6 12.2 1100 11.1 14.6 14.9 9.1 12.6 1200 15.3 19.1 24.6 9.0 17.1 1300 19.4 20.5 15.4 10.6 16.8 1400 21.9 23.6 21.5 12.3 20.2 1500 22.5 21.3 24o6 19.7 22.0 1600 19.2 20.5 3559 16.7 22.7 1700 14.9 15.7 34.4 13.2 19.0 1800 13.3 16.7 25.0 14.7 17.2 1900 17.3 15.6 14.1 14.7 1595 2000 24.0 16.7 9.7 20,6 18.0 2100 32o00 16.7. 13.4 18.8 2200 29.3 16.7 16l1 14.9 19.4 2300 25.3 20.0 16.1 19.7 20.4 2400 24.3 20.2 11.5 18.2 19.0 5

c Enrico Fermi Power Plant 30-0L -- 201. LL. 10- o a) 0C 2 4 6 8 10 12 14 16 18 20 22 24 Time in Hours WJBK-TV Tower 50 - C 0O L_ Q) 40 C a) - 30 eS T._Mean L - 0 20 a, I0 6 12 18 24 Time in Hours Fig. 1. Diurnal variation of inversions at the Enrico Fermi site and at WJBK-TV tower: Winter, 1956-1957. 6

C 0 Enrico Fermi Power Plant 530 o 0 - S20|. _- - Mean L, 0 - 2 4 6 8 10 12 14 6 18 20 22 24 Time in Hours WJBK-TV Tower 50 C Q) 40 C 30 a' ~Mean c20 0 6 12 18 24 Time in Hours Fig. 2. Diurnal variation of inversions at the Enrico Fermi site and at WJBK-TV tower: Spring, 1957. 7

.. _ Enrico Fermi Power Plant o L 30 - a. o - I Mean 20 ____ c 20 -- -... --- 0L 2 4 6 8 10 12 14 16 18 20 22 24 Time in Hours WJBK-TV Tower c 1000 20 - C 2 4 6 8 0 12 14 16 18 20 22 24 Time in Hours Fig. 3. Diurnal variation of inversions at the Enrico Fermi site and at WJBK-TV Tower: S er, 19 I 100c 80i U u_ 60C 0 LMean 20 6 12 18 24 Time in Hours Fig. 5. Diurnal variation of inversions at the Enrico Fermi site and. at WJBK-TV tower: Summer, 1957. 8

4- __________________________ ________________ c Enrico Fermi Power Plant 0 30 0. C 202 4 6 8 10 12 14 16 18 20 22 24 Ti me in Hours WJBK- TV Tower 50 a 40- eMean 30 C 1020 2 4 6 0 12 14 16 18 20 22 24 Time in Hours Fig. 4. Diurnal variation of inversions at the Enrico Fermi e ad at WK-TV WJBK-TV TowerFl 1 50 ~ - C) 0 a.. 40m - ~ - _ Mean 0 6 12 18 24 Time in Hours Fig. ^4. Diurnal variation of inversions at the Enrico Fermi site and at WJBK-TV tower: Fall, 1957. 9

e |Enrico Fermi Power Plant a 30 a. c20 - 10 0 I I 0 c 50 Q. L. Q) Fig. 5. Diurnal variation of inversions at the Enrico Fermi site and at WJBK-TV tower: Annual Summary, 1956-1957. 10 o ~ ~ ~ 61 82

4, THE PERSISTENCE OF INVERSIONS The inversion climatology of any site can be characterized usefully -by the duration of inversions as was done in the first and second progress reports. Inversion duration is determined as follows. Each occurrence of inversion conditions which persists for a number of consecutive hours is considered to be a single inversion. Its duration is simply the number of consecutive hours of inversion, except that an occurrence of one hour of weak lapse rate within the sequence of inversion hours is not considered a break in the continuous inversion. For example, six consecutive hours of inversion followed by a one-hour weak lapse rate and then five more hours of inversions would be treated as an inversion of 12 hours durationo Many inversions occur as isolated 1-, 2-, or 3-hour events both at the WJBK-TV tower and at the Enrico Fermi site. It is reported that at the WJBKTV tower "the highest duration frequency is in the 1 to 3-hour period."2 Inversions of short duration are quite frequent at the Enrico Fermi site also, since most of the afternoon inversions associated with the lake-breeze effect form after noon and disappear an hour or more before dark. However, in the present analysis, attention is focused on inversions of 6 hours or more duration since these have somewhat different implications than shorter inversions in problems of diffusion. The substance of the difference between the Enrico Fermi and the WJBK-TV sites can be described more clearly in words than graphically. In Section 2 it was stated that inversions occur 31.1% of the time at the WJBK-TV tower and only 19.0% of the time at the Enrico Fermi site. Although there are gaps in the record at both stations due to equipment failure, the number of hours of lapse-rate data available at the two stations is practically identical, 6754 at WJBK-TV and 6748 at the Enrico Fermi site. Hence it is not necessary to present the comparison in terms of percentages. During the period of record from December 1, 1956, to November 30, 1957, there were 141 occurrences of inversions at the WJBK-TV tower which exceeded 5 hours in duration, but only 70 such occurrences at the Enrico Fermi site. Nevertheless, there were 5 inversions lasting longer than 24 hours at the Enrico Fermi site but none of this duration at the WJBK-TV towero These 5 prolonged occurrences consisted of inversions of 43 and 50 hours in the winter, 26 and 34 hours in the spring, and 50 hours in the summero The appearance of these very lengthy inversions at the Enrico Fermi site is related to yet a third important mechanism, which results from the adjacent lake surface. Under certain meteorological conditions a broad southerly flow of air is established over the eastern portion of the United Stateso When this happens, unseasonably warm air from the Gulf of Mexico ranges far north of its normal limits, moving out across Lake Erie where it is cooled by the surface of the lake, thus forming an inversiono It is convenient to designate this type of inversion as circulation inversions because of their means of formationo This distinguishes them from nocturnal inversions formed by surface cooling, and the afternoon inversions caused by the lake-breeze effect, The essential ingredi11

ents of this circulation type of inversion are a southerly flow of air, and air temperatures that are several degrees above the temperature of the lakeO A number of these circulation inversions were observed in the first year of operation, and the question naturally arises of how often they are likely to occur. The frequency of inversion is related both to the temperature of the lake and the frequency and magnitude of positive departures from normal temperature. A very good estimate of lake temperatures near the Enrico Fermi site is provided by water intake temperatures at the Monroe waterworks. Five years of records from 19553 through 1957 of intake temperatures have been analyzed for this purpose. A comprehensive analysis of the frequency and magnitude of positive departures from normal temperatures could constitute an extensive investigation in its own right. A less elaborate analysis that still gives useful results is described in the following paragraphs. A study of positive temperature anomalies (i e,, departures from normal) at Toledo was undertaken to learn something about the frequency and magnitude of warm spellso Seven years of records were examined for occurrences of positive anomalies greater than or equal to 10~Fo The results of this study are presented in Table VIo TABLE VI FREQUENCY AND MAGNITUDE OF POSITIVE TEMPERATURE ANOMALIES BY MONTHS AT TOLEDO, OHIO, DURING A PERIOD OF 7 YEARS Number of Occurrences by Months Anomaly, ~F Jan. Febo March Apr. May June July Auge Septo Octo Nov. Dec. 10 63 52 42 41 29 37 21 19 24 50 42 45 15 32 20 16 24 3 6 1 2 5 24 17 23 20 15 6 7 7 0 0 0 0 0 4 5 9 25 6 1 0 0 0 0 0 0 0 0 1 3 It turns out that the magnitude of positive temperature anomalies is much greater in the winter than the summero However, insofar as the formation of the inversions is concerned, greater temperature anomalies are needed in the winter since the lake temperature is several degrees above the average air temperature The variables have been brought together in the following wayo During the two winter inversion occurrences, temperatures of 25~F and 27~F above normal were recorded at Toledo Express Airport which corresponded to temperatures 16~F and 19~F above the lake temperature at Monroeo During one of the spring occurrences, the temperature was 22~F above normal and above the lake temperatures In addition, on one occasion in the summer, when except for two consecutive hours of weak lapse rate an inversion persisted for 55 hours, the temperature 12

was 15~F above normal and 20~F above the lake temperature. Based on these occurrences, a favorable thermal regime for the formation of prolonged inversions has been set tentatively as an air temperature 15~F above the lake temperature. Now considering the month of January, in which the average lake temperature is 35~F, an average air temperature of 5CF at Toledo provides a favorable regime for inversion formation. Since 26~F is the normal January temperature at Toledo, 50~F corresponds to a temperature anomaly of 24~Fo In the Toledo records of 7 years, 8 occurrences in January of anomalies greater than or equal to 24~F, or a little better than 1 per year, were recorded. Similar computations have been made for each month of the year and are presented in Table VII. Certain inferences may be drawn from Table VII. Clearly, thermal regimes favorable for the formation of prolonged inversions occur most frequently in the spring and through June, after which their frequency falls off abruptly. On a seasonal basis a favorable regime occurs about 2 times per winter, 11 times per spring, 6 times per summer (5 of these in June), and about once every 2 years in the fallo Since this analysis does not take wind direction into account, or the fact that some occurrences of the required temperature anomaly were on consecutive days and would therefore initiate only one prolonged inversion, the numbers obtained should not be taken literally. In addition, it is by no means certain that prolonged inversions will not form when air temperatures at Toledo are only 10~F above lake temperatures, However, it is completely warranted to assert that prolonged inversions at the Enrico Fermi site are least probable in the fall and most probable in April, May, and June. No doubt the absence of any lengthy inversions in the first fall of record, at the Enrico Fermi site, and the infrequency of inversion conditions in the fall as noted earlier in this report, reflect these findingso 5. THE ASSOCIATION OF LAPSE RATES WITH WIND SPEED Inasmuch as an inversion is often a manifestation of stagnant air conditions, it is usual to find that winds are lighter during inversions than at other timeso It is not simply an association of the two conditions; it is a cause and effect relationship. Under steep lapse rates, vigorous mixing transports momentum from aloft to the surface layers, and wind speeds are high. When inversions develop, vertical mixing is inhibited, the transport of momentum from aloft diminishes, and surface winds decrease, To some extent this pattern appears at the Enrico Fermi site, Once again, however, the presence of the lake influences the association of wind speed and lapse rate. For purposes of this analysis, two classes of lapse rates, inversion and noninversion, have been usedo The percentage occurrence of inversion and noninversion and the average wind speed for each class have been computed for each wind direction, The results of this analysis are presented in Tables VIII through XII for each of the seasons and for the entire year from 1 December 1956 to 50 November 19570 Figures 6-10 provide a graphical display of the same informationo 13

TABLE VII THE FREQUENCY OF THERMAL REGIMES FAVORABLE FOR THE FORMATION OF PROLONGED INVERSIONS AT THE ENRICO FERMI SITE SHOWN AS A FUNCTION OF MEAN LAKE TEMPERATURES AT MONROE AND NORMAL AIR TEMPERATURES AT TOLEDO (All temperatures in ~F) Variables Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Novo DecN Mean lake temperature 755 55 56 45 55 64 71 72 68 59 47 58 Required air temperature for inversion (add 15~F to lake temperature) 50 50 51 58 68 79 86 87 85 74 62 55 Normal Toledo temperature 26 27 56 46 58 69 75 71 64 55 40 29 Required temperature anomaly at Toledo for inversion (line 2 minus line 1) 24 25 15 12 10 10 15 16 19 21 2 24 Number of occurrences of required anomaly at Toledo in 7 years of record 8 2 15 533 29 57 6 1 0 2 1 5 Number of occurrences of required anomaly by seasons Winter - 15 Spring - 75 Summer - 44 Fall -5

TABLE VIII MEAN WIND SPEEDS ASSOCIATED WITH INVERSIONS AND NONINVERSIONS AT THE ENRICO FERMI SITE 1 December 1956 - 28 February 1957 (Winter) Win Inversion Noninversion Wind-. Occurrence, Mean Speed, Occurrence, Mean Speed, Direction mph mph N 0.7 6.7 2,6 16,6 NNE 0,7 7.0 5.0 17.5 NE 0.5 10.9 5.2 17o0 ENE 0.9 12,8 235 10o5 E 1.0 11.8 1.8 11.2 ESE o 1 11.8 2.6 11.0 SE 1.9 10,0 1.7 11.2 SSE 1.1 10.7 1.2 9.9 S 1.1 11o6 3.1 12.8 SSW 3.0 14,2 6.9 16 3 SW 2.8 15.5 8.3 14.o WSW 2.2 12.5 15.4 15.1 W 1.5 10.7 7.4 12.1 WNW 0.9 8,1 7,4 11.6 NW 1.3 6.5 6.4 11o6 NNW 0,5 6.2 4.8 12.1 Calm 0.1 0.0 o.6 0.0 Totals 21.5 78.7 Average 11.4 1532 15

NONINVERSION INVERSION N N NE NW^ \ NW/ ^ NE 15% 8 mph / / 157eamph 10 0\J~/,~-~X ~ t SW SE SW EE S S Fig. 6. Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Winter, 1956-1957.

TABLE IX MEAN WIND SPEEDS ASSOCIATED WITH INVERSIONS AND NONINVERSIONS AT THE ENRICO FERMI SITE 1 March 1957 - 31 May 1957 (Spring) Wind. __ Inversion Noninversion Direction Occurrence, Mean Speed, Occurrence, Mean Speed, Direction mp mph _ _ mph mph N 0.3 6.9 2.7 13.1 NNE 0.7 7.7 6.2 14,0 NE 0o5 8.1 6,8 16.0 ENE 0,4 8.9 9,5 15.6 E 0.8 12.6 6.8 18.5 ESE 1.5 14. 9 5.2 12.8 SE 2.0 14o 6 2.6 12.6 SSE 2.9 12,3 2.4 8.5 S 2.6 10.9 2.0 9.8 SSW 2.2 10,7 3.1 11.8 SW 1.2 12,3 6.2 14,0 WSW 1.0 9.0 8.4 17.1 W o,6 10.0 5c8 1453 WNW o,8 10.8 7,9 14.7 NW 0,3 7.0 4.1 13.8 NNW 0.6 8.8 1.7 11.6 Calm 0,1 0.0 0.1 0.0 Totals 18.5 81o5 Average 11,3 14.7 17

NONINVERSION INVERSION N N ~/ W^ /15%amh 15mph 0 I0 W I E WE E SW S SE S S Fig. 7. Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Spring, 1957.

TABLE X MEAN WIND SPEEDS ASSOCIATED WITH INVERSIONS AND. NONINVERSiIONS. AT THE ENRICO FERMI SITE 1 June 1957 - 31 August 1957 (Summer) _Wind Inversion Noninversion Direction Occurrence, Mean Speed, Occurrence, Mean Speed, mph mph N o09 7.0 2.5 7c4 NNE 2.1 10.7 2.5 8o5 NE 1.7 15. 7 4.0 14. ENE 0.5 8.4 5.4 12.0 E 0.4 2.5 538 116 ESE 0.7 12.5 4.8 10.9 SE 2.4 10.5 2.4 8.5 SSE 2.9 9.8 358 9 4 S 2.4 8.2 5.6 10.5 SSW 0.7 7.6 7.5 10o5 SW 0.7 5.4 8.6 11.2 WSW 0.7 6.9 7.8 11.1 W 0.9 6.7 7.2 11.3 WNW 1.2 6.1 6.7 12.3 NW 0.6 6,8 4.5 8.7 NNW 0.4 7.0 3.7 8.6 Calm 0,1 0.0 0.0 Totals 19.3 80.8 Average 9.0 10.7 19

NONINVERSION INVERSION N N NW,, NE NW, NE I0 I 0 8 W. E W - E sw -SE sw E S S Fig. 8. Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Summer, 1957.

TABLE XI MEAN WIND SPEEDS ASSOCIATED WITH INVERSIONS AND NONINVERSIONS. AT THE ENRICO FERMI SITE 1 September 1957 - 30 November 1957 (Fall) Wind. __ Inversion Noninversion r lcl Occurrence, Mean Speed, Occurrence, Mean Speed, Direct ion mph mph _____ mph __ mph N 0.5 8.4 6,0 10.0 NNE 0.9 8.9 2,1 9.4 NE 0.8 8.6 6.5 15.5 ENE 0.8 8.1 539 15.5 E 0.6 9.0 1.4 9o9 ESE 1.1 8o7 4.2 9.3 SE 0.8 17.8 2.4 9.9 SSE 1,6 1536 4.5 10.5 s 0.8 9.6 4.9 10.9 SSW 1.7 11.7 8.6 1253 SW 1.7 9.0 6.0 12.5 WSW 0.9 6.9 9. 14.7 W 1.9 9.7 2.7 11o7 WNW 1.7 9.0 5.5 10o8 EN 0.6 7.3 6.4 10o9 NNW 1.1 7~7 8.2 11.1 Calm 0.0 0.0 0.4 0.0 Totals 17.5 8217 Average 10.5 11.8 21

NONINVERSIONS INVERSIONS N N NWE NE NW >NE 15%a mph 15% a mph I0 I0 w -,- -E w — E SW E SE S S Fig. 9. Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Fall, 1957.

TABLE XII MEAN WIND SPEEDS ASSOCIATED WITH INVERSIONS AND, NONINVERSiIONS. AT THE ENRICO FERMI SITE 1 December 1956 - 30 November 1957 (Annual Summary) W. ind. _ Inversion Noninversion Direction Occurrence, Mean Speed, Occurrence, Mean Speed, mph _^ mph N 0,6 6.8 3.3 11.6 NNE lo1 9.1 3.7 15.5 NE 0.8 ll1 5e7 15.8 ENE 0.6 9.9 5.6 14.5 E 0.7 10.4 3.7 15.4 ESE 1.1 12.5 4.2 11.5 SE 1,9 12.4 23 10. 8 SSE 2,1 11.7 2.8 9 6 S 1.8 10.1 3.7 11.0 SSW 2,0 12.0 6.2 12.9 SW 1.6 12.5 7.2 13.0 WSW 1.2 9.9 9.8 14,2 W 1.2 9.6 5.8 12.5 WNW 1.1 8.6 6.9 12,7 NW 0.7 6.8 553 11,4 NNW 0o6 7.7 4,3 11.0 Calm 0.1 0.0 0.2 0.0 Totals 19.2 80.7 Average 10.5 12.8 23

NONINVERSION INVERSION N N NWW -NE NW >NE \ 15%n mph / 1. 15% amph rW I Wt -, I s E W0 - E S S Fig. 10. Percentage frequency of inversions and noninversions associated with winds for 16 directions and corresponding wind speed in mph at the Enrico Fermi site: Annual Summary, 1956-1957

For each of the seasons, combining all wind directions, the average wind speed is less for the inversion than for the noninversion classo However, for winds from the ESE, SE, and SSE, the directions associated with the circulation type of inversion discussed in the previous section, wind speeds are actually somewhat higher for the inversion than for the noninversion class. Another relevant aspect is displayed quite strikingly in the inversion windrose of Figs. 6-10, where it can be noticed that winds from the sector WNW clockwise through NI\IE are quite light compared to the diametrically opposed sector ESE through Se The contrast in wind speeds noted here is magnified by the fact that winds from the WNW through N are over the land with its relatively high frictional effects, whereas winds from the ESE through S cross the lake where frictional effects are smallo This does not account for the fact that winds from the ESE, SE, and SSE are stronger during inversions than noninversions, One possible explanation for this may be that the pressure gradient is usually stronger during the warm outbreaks of air which feature circulation inversions than it is with other winds from the same direction, Another curious feature of the data is that, given calm conditions, inversions are less frequent than noninversionso 60 THE ASSOCIATION OF LAPSE RATES WITH WIND DIRECTION Because winds from different directions occur with varying frequencies, a simple table displaying the number of hours of inversion for each wind direction fails to show the association of lapse rate with wind direction. What is needed is a summary of the data which indicates, for any given wind direction, the relative frequency of inversion conditions and strong lapse-rate conditionso For example, if there were 200 occurrences of SW winds during a season, and if there were an inversion on 20 of those occurrences, one would compute the relative frequency of inversions to be 10% for SW winds. If during the same season there were 30 occurrences of SE winds, and if there were an inversion on 20 of those occurrences, one would compute the relative frequency of inversions to be 67% for SE winds. A reasonable conclusion would be that there was a marked association or correlation between SE winds and inversions and little correlation between SW winds and inversions. The data for the first year have been analyzed in this way on a seasonal basis and on an annual basis so that the association of lapse rate with wind direction is clearly revealed. The last 3 columns of Tables XIII-XVII give frequencies for the three lapse-rate categories, strong, weak, and inversion. These would be referred to by the statistician as conditional frequencies, ioe., the frequency conditional on the wind being from the given directiono Figure 11 displays the association of inversions with wind direction by plotting from Tables XIII-XVII the frequency of inversions as ordinate against wind direction as abscissa. Interpretation of the data is aided by referring to the mean lake temperatures and normal Toledo temperatures in Table VII, which show that the lake is cold in comparison to air temperatures during the spring and early summer and warm in comparison to air temperatures during the fall and winter. Recall also that, as pointed out in the discussion of circulation-type inversions, positive temperature departures large enough to cause inversions in S to SE winds are un25

TABLE XIII THE ASSOCIATION OF TEMPERATURE LAPSE RATES WITH WIND DIRECTION AT THE ENRICO FERMI SITE 1 December 1956 - 28 February 1957 (Winter) Hourly,....... Frequency of Lapse Rates as a.Wind Hourly Lapse Rates Compass Percent of Compass Totals for Direction Totals a Given Wind Direction S W I S W I N 44 1 13 58 75~9 1.7 22o4 NNE 36 17 12 65 55 4 26,2 18.5 NE 73 19 9 101 72 o 18,8 8.9 ENE 22 19 15 56 39o3 3359 26.8 E 14 17 18 49 28,6 34 7 36 7 ESE 24 21 19 64 37 5 32 8 29.7 SE 23 7 33 63 36o5 11.1 52o4 SSE 14 7 20 41 34 1 17el 48.8 S 23 32 19 74 31 o 43o2 25.7 SSW 65 56 53 174 37. 4 32 2 30. 5 SW 55 91 50 196 28o1 46o4 25.5 WSW 111 123 39 273 40o 7 45 o1 14.3 W 72 58 27 157 45o 9 36 9 17 2 WNW 85 45 16 146 58.2 30o8 11.0 NW 84 28 22 134 62 7 20o 9 16,4 NNW 64 20 9 93 68.8 21.5 9.7 Calm 4 6 2 12 3353 50o0 16.7 Totals 813 567 376 1756 Code' S = A lapse rate in excess of the dry adiabatic lapse rate. W = A positive lapse rate that is less than the dry adiabatic lapse rateo I = A temperature increase with heighto 26

TABLE XIV THE ASSOCIATION OF TEMPERATURE-LAPSE RATES WITH WIND DIRECTION AT THE ENRICO FERMI SITE 1 March 1957 - 31 May 1957 (Spring).......................... Frequency of Lapse Rates as a Windourly La Compass Percent of Compass Totals for Direction Totals a Given Wind Direction S W I S W I N 52 5 7 64 81.3 7.8 10o9 NmE 128 5 15 148 86,5 3.4 10lo NE 141 5 11 157 89,8 352 7~0 ENE 196 8 9 213 92.8 3.8 4,2 E 136 9 17 162 84.o0 56 10.5 ESE 101 11 32 144 70e 1 7 6 22 2 SE 46 10 43 99 46,5 10o 1 43.4 SSE 40 11 61 112 3557 9.8 54.5 S 24 18 56 98 24-.5 18.4 57.1SSW 52 14 47 113 46 0 12. 3 42.6 SW 95 37 26 158 60,1 23.4 16 5 WSW 156 24 22 202 77o2 11.9 10 9 W 101 22 13 136 741 3 16.2 9 6 WNW 156 1 8 187 83o4 7.0 9.6 NW 75 12 6 93 80.6 12.9 6.5 NNW 26 11 12 49 53.1 22 4 24.5 Calm 0 1 2 3 0.0 331 3 66,7 Totals 1525 216 397 2138 Code: S = A lapse rate in excess of the dry adiabatic lapse rate. W = A positive lapse rate that is less than the dry adiabatic lapse rateo I = A temperature increase with heighto 27

TABLE XV THE ASSOCIATION OF TEMPERATURE-LAPSE RATES WITH WIND DIRECTION AT THE ENRICO FERMI SITE 1 June 1957 - 31 August 1957 (Summer) Frequency of Lapse Rates as a Hourly Lapse Rates Wind Compass Percent of Compass Totals for Direction Totals a Given Wind Direction S W I S W I N 31 7 13 51 60o8 1537 25,5 NNE 34 5 32 71 47o9 7o0 45ol NE 58 1 25 84 69.0 12 29.8 ENE 78 2 8 88 88,6 2.3 9.1 E 51 5 6 62 82o2 8.1 9.7 ESE 50 21 10 81 61o7 25 9 12 4 SE 22 14 37 73 30o2 19o2 50o6 SSE 35 21 42 98 35 7 21. 4 4.2.9 S 56 28 36 120 46 7 23 53 30o0 SSW 91 22 11 124 735 4 17.7 8o9 SW 102 25 11 138 7359 18.1 8o0 WSW 108 6 10 124 87o1 4.o8 8.1 W 100 9 14 123 81.3 7.3 11 4 WNW 96 4 18 118 81 53 3 4 15o3 NW 62 5 9 76 81o6 6 o6 11o8 NNW 54 1 6 61 88.5 1o 6 9.9 Calm 0 0 1 0.0 0.0 100 0 Totals 1028 176 289 1493 Code: S = A lapse rate in excess of the dry adiabatic lapse rate. W = A positive lapse rate that is less than the dry adiabatic lapse rate, I = A temperature increase with height. 28

TABLE XVI THE ASSOCIATION OF TEMPERATURE-LAPSE RATES WITH WIND DIRECTION AT THE ENRICO FERMI SITE 1 September 1957 - 30 November 1957 (Fall).. Hourl R s | Frequency of Lapse Rates as a Windourly Laps Compass Percent of Compass Totals for Direction Totals a Given Wind Direction S W I S W I N 82 8 7 97 84o5 803 7o2 NNE 30 2 14 46 65o3 4,4 30~3 NE 94 1 12 107 87.9 0.9 ll 2 ENE 54 4 12 70 77.1 5,7 17o2 E 19 2 9 30 63 3 6o7 30o0 ESE 59 4 16 79 74 6 501 2003 SE 33 3 12 48 68.7 6o3 25o0 SSE 56 11 24 91 61l5 1201 26,4 S 68 6 12 86 79e0 7.0 14o0 SSW 118 12 25 155 762 7 16 1 SW 77 13 25 115 66,9 115 3 21,8 WSW 125 17 14 156 80 1 10o9 9o0 W 37 3 28 68 54,4 4,4 41,2 WNW 74 5 25 104 712 4,8 24.0 NW 90 6 9 105 85,7 5~7 806 iNW 122 1 17 14O 87 2 0,7 12 1 Calm 6 0 0 6 100.0 0o0 O o Totals 1144 98 261 1503 Codee: S = A lapse rate in excess of the dry adiabatic lapse rate. W = A positive lapse rate that is less than the dry adiabatic lapse rate, I = A temperature increase with height. 29

TABLE XVII THE ASSOCIATION OF TEMPERATURE-LAPSE RATES WITH WIND DIRECTION AT THE ENRICO FERMI SITE 1 December 1956 - 30 November 1957 (Annual Summary) HourlyLapseRats Frequency of Lapse Rates as a Wind Hourly Lapse Rates Compass Percent of Compass Totals for Direction Totals a Given Wind Direction s w I S W I N 209 21 40 270 77.4 7.8 14 8 NNE 228 29 75 330 69.1 8.8 22. 1 NE 366 26 57 449 81o5 5.8 12 7 ENE 350 33 44 427 82.0 7.7 10.3 E 220 33 50 303 72.6 10.9 16.5 ESE 234 57 77 568 63.6 15.5 20.9 SE 124 54 125 285 43.8 12.0 44 2 SSE 145 50 147 342 42.4 14.6 43.0 S 171 84 125 378 45.2 22,2 52,5 SSW 326 104 1366566 576 18.4 240 SW 329 166 112 607 54.2 27.3 18 5 WSW 500 170 85 755 66.2 22.5 11.3 W 310 92 82 484 64.0 19.0 16.9 WNW 411 67 77 555 74.1 12. 1 13.9 NW 311 51 46 408 76.2 12.5 11.5 NKW 266 33 44 343 77 6 9.6 12 8 Calm 10 7 5 22 45.5 51.8 22 7 Totals 4510 1057 1323 6890 Code' S = A lapse rate in excess of the dry adiabatic lapse rate. W = A positive lapse rate that is less than the dry adiabatic lapse rate. I = A temperature increase with height. 3o0

likely to occur in the fall. The following features are evident from Fig. 11 and the five associated tableso During the winter, inversions were relatively more frequent with SE and SSE winds than with any other wind directiono This effect is present, despite the relative warmth of the lake at this time, mainly because there were two prolonged inversions due to warm spells 25~F and 27'F above normal temperatureso During the spring the influence of the comparatively cold lake is very pronounced with a high relative frequency of inversions when winds are from the SE through SWo This effect is less pronounced in summer since only in June is the lake relatively cold, but the association of inversions with SE and SSE winds is still present. During the fall, scarcely any pattern emerges, presumably because the comparatively warm lake temperature does not promote the formation of inversionso The association of strong lapse rates with wind direction is essentially a complementary picture to that of inversions. Strong lapse rates occur least frequently with winds from the SE through S and most frequently with winds from the W through N to NE. However, as in the case of the association of inversions with wind direction, the pattern is not very evident during the fall. 7o SUMMARY The inversion climatology of the Enrico Fermi site apparently differs from that of inland stations such as the WJBK-TV tower in a number of wayso The salient features of these differences are enumerated below. a. Inversion conditions are more frequent at the WJBK-TV tower than at the Enrico Fermi site. Although this difference appears at all seasons, it is most noticeable in the fall when inversions are about twice as frequent at the TV tower as at the plant site. b. Most of the inversions that occur at the TV tower are of the nocturnal type which is associated with light winds and poor diffusion conditions. On the other hand, three distinct types of inversions occur at the Enrico Fermi site, namely, nocturnal, circulation, and lake breeze. The latter two types of inversions which represent more than half of all the inversions are associated with wind speeds greater than or equal to 10 mph, ioe, they do not necessarily imply the poorest type of diffusion conditions. Co Circulation inversions at the plant site may persist for over two days or as long as extremely warm air crosses Lake Erie from the south. Circulation inversions are most probable in the months of April, May, and June, and least probable in the fall. 51

60 — _ ~ ~~_ ~ Winter 4020 0 N NE E SE S SW W NW 60 -- S p ring 4020 C, N NE E SE S SW W NW 60 Summer o N NE E SE S SW W NW 0' 400c - N NE E SE S SW W NW 60 - S~~~~~~Annual Summal ry 40 20 N NE E SE S SW W NW Annual Summary 40 - 20 0 N NE E SE S SW W NW Wind Direction Fig. 11. Frequency of inversions associated with wind direction for the Enrico Fermi site for all seasons and annual summary, 1956-1957. 32

II ANALYSIS OF WIND DATA 1o INTRODUCTION The second progress report included a discussion of the winds observed at the Enrico Fermi site during the winter and spring of 1956-57" The present report extends this analysis through the summer and fall of 1957 with some remarks about annual wind statistics and some inter-seasonal comparisons. The wind records for the plant site are compared with current observations at Toledo and Detroit, and to a 5-year record at Toledo Municipal Airporto In earlier progress reports reference has been made to the unfortunate bias which persists in the wind records for Detroit City Airporto This bias takes the form of an apparently greater frequency of the winds from the 8 cardinal compass points than from the intermediate points, Although a bias of this type does not generally appear in the record at Toledo,* it is all too common in wind observations across the countryo In the course of other research at the Meteorlogical Laboratory, a method has been developed for taking a biased wind record, such as that at Detroit, and converting it into a good approximation of what the unbiased record should be. This method is described in detail in Appendix Ao By means of this method, the reported wind occurrences at Detroit City Airport which appear in Tables XX, XXV, XXX, XXXV, and XL for the period 1 December 1956 to 30 November 1957 have been converted into an unbiased recordo The unbiased record is presented in Tables XXI, XXVI XXXI, XXXVI, and XLI, Although the evidence of bias was not great for the winter season, it was very strong for the other three seasons and for the annual summaryo In the discussion which follows, the Detroit City Airport wind-direction frequencies referred to will be the computed unbiased record of Tables XXI, XXVI9 XXXI, XXXVI, and XLIo 2. WIND DIRECTIONS AT THE ENRICO FERMI SITE The discussion of wind-direction statistics will be carried on in relation to the population centers of interest in the manner of earlier progress reportso For convenience in interpretation, a topographic map of the site and surroundings is reproduced in Fig. 12. The actual records of winds at the Enrico Fermi site, Toledo Express Airport, Detroit City Airport, and the 5-year reference record at Toledo Municipal Airport followed by a windrose presentation of the same data appear on successive pages grouped according to seasons. These are Tables XVIII -XLII, and Figs. 15-17. Although the records for winter and spring are repeated in this report to provide a complete record for a year, the *The Toledo record for the fall of 1957 appears to be biasedo 33

/ / DETROIT CITY rrF LAKE AIRPORT \ W{L LO W lie^O \)rk^ \ ^CLAIR / ^^l RUN N IRPORT \ ^ \ ~~~~~~~~~~/! I!~~~~~~~Li E R. a tt~naj,~~~~~~~~~ TOL EDO EXPRESSO tLD AIRPORT:~~MUNICIPAL S A AIRP ORT i~~~ Fig. 12. Topographic m map of site and surroundings.

TABLE XVIII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Enrico Fermi Site (Aerovane at height of 102 ft) 1 December 1956 - 28 February 1957 (Winter) Speed, mph TotalMean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and. No. ~ of OverOver Over NOr mph all Mean N 0.1 1.7 1.2 0,6 3.5 3.6 78 14,5 111 NNE 0,2 12 12 7 0,5 34 3.6 76 15,4 118 NE 0.3 1.0 359 0.5 54 5.6 120 16.8 128 ENE 0,2 1 3 1.2 2 5 2.7 60 12.2 93 E 0.3 1.0 102 2.2 2,5 54 12.0 92 ESE 0.1 1.9 o.0 2.9 3o0 64 11.5 88 SE 0.3 1.6 1.0 2.6 2.9 63 10.8 82 SSE 0.1 1.1 0.9 2.0 2,1 46 12.1 92 S 0.2 1.8 2.1 0.1 4.0 4 2 89 13.2 101 SSW 0.2 2.7 5.7 0.3 8.7 8.9 193 15.3 117 SW 0.3 357 7.0 0,o 10,8 11.1 240 12.9 98 WSW 0,2 7 5 6,9 14.4 14 6 315 14o6 111 W 0o5 5.4 4,3 0,1 9.8 10,3 223 12.4 95 WNW o 5 5.1 4.1 0.1 9.3 9.8 213 12o3 94 NW 007 5o1 2.6 0.1 7.8 8,5 183 10.9 83 NNW 0ol 3.6 2.4 6.0 6,1 131 12.0 93 Calm o 6 _ 6 12 0.0 Totals 408 45,7 47,2 2.4 95-3 100.1 2160 Mean 1351 100 55

TABLE XIX PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Express Airport (Wind instruments at height of 72 ft) 1 December 1956 - 28 February 1957 (Winter) S eed mph TotalMean Speed Mean Speed Wind 25 Total Observations Direction 0-3 -4-12 13-24 and 4 and of OverOver Over o% mph all Mean N 0.3 351 2o0 5.2 5o5 118 10o8 104 NNE 0.1 2e1 1o4 3o6 3o7 80 11o0 106 NE 0.2 2.6 11o 3o7 3.9 85 10.0 96 ENE 0o4 2.0 0.7 2.7 351 68 9.0 86 E 0,4 2,4 0.8 352 356 77 9.1 87 ESE 0o5 2.1 0o3 2,4 2.8 61 7o5 58 SE 0o4 1.9 1.9 2.3 50 6o0 58 SSE 0o6 2.5 0,2 2.7 353 71 7.4 71 S 0o4 4 3 1.9 6.2 6.6 142 10o0 96 SSW 0.3 2.9 355 0.2 6.6 6.9 148 12o6 121 SW 0.2 5o5 6.o Ool 11.8 11.9 258 12o9 124 WSW 0o2 8.8 7o4 0ol 16o3 16.5 357 11.9 114 W 0.1 5.3 2,7 8.0 8.o 175 10o8 o04 WNW 4.4 2.0 6 6.5 141 10.4 100 NW 0.3 4.8 1.7 6o5 6,9 148 9e9 95 NNW o.5 358 le4 5.2 5o7 123 9o5 91 Calm 27 _ _ 2.7 58 OoO Totals 7o6 5805 5332 0o4 92.5 100o0 2160 Mean 10o 4 100 56

TABLE XX PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Detroit City Airport (Wind instruments at height of 81 ft) 1 December 1956 - 28 February 1957 (Winter) Speed, mph TotalMean Seed Wind 25 Total Observations Mean peed Direction 0-3 4-12 13-24 and 4 and of Over-....,....Over Over NO mph all Mean N 0.7 6.7 3.8 10.5 11.2 243 10,4 94 NNE 0 3 2.5 1.2 3 8 4.1 88 10.2 92 NE 0.6 1.3 0o4 1.7 253 4-9 7o7 69 ENE.Oo 2.7 0.4 3.1 3.2 69 8.9 80 E 0,7 3.3 0.3 356 4,3 93 7.0 63 ESE 0 3 1.4 0,0 1.4 1 7 37 6.9 62 SE 0.1 2.4 0.1 25 27 58 6.6 59 SSE 0.1 3.5 0.3 3.8 359 85 8.o 72 S 0 5 5.1 2.1 7.3 7.8 168 10.1 91 SSW 0.0 2.0 2.8 )o9 4,9 105 12,6 113 SW 0.1 4.7 6.9 0.2 11.8 11o9 257 13.3 120 WSW 0.0 3.3 3.7 7o0 7.0 151 12.5 113 W 0.1 5.8 5o8 0.3 11o6 11.7 253 12,1 109 WNW 0.2 2.5 5.8 0.1 8.7 8.8 191 14.0 126 NW 0. 5 4.4 356 8o1 8.6 186 11.6 104 NNW 0.2 2.2 2,8 5 0 5,2 112 12.6 113 Calm 0.7 _0,7 15 0,0 Totals 5.2 53.9 40.0 06 94.o8 100.0 2160 Me an 11.1 100 37

TABLE XX PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS, BIASED AND UNBIASED Detroit City Airport 1 December 1956 - 28 February 1957 (Winter) — Wind' "- Total Observations Windci. Biased Record Unbiased Record Direction | No. No........ No. _ _ _ I No, N 243 11.2 190 8.8 NNE 88 401 108 50o NE 49 203 44 20 ENE 69 352 71 303 E 93 403 81 308 ESE 37 1 7 42 1 9 SE 58 207 47 202 SSE 85 359 94 404 S 168 708 136 603 SSW 105 409 156 7 2 SW 257 11 9 199 9o2 WSW 151 7 0 214 9 9 W 253 11.7 219 lOo1 WNW 191 8o8 222 1o 3 NW 186 8o6 158 7 3 NNW 112 5o2 164 7.6 Calm 15 Oe7 15 07 Totals 2160 100.0 2160 100,0 58

TABLE XXII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Municipal Airport (Wind instruments at hLeigffiU of 47 ft) 1 January 1950 - 31 December 1954 (Winter Seasons) Speed, mph Total Mean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and of OverOver Over NO_ mph all Mean N 0.3 2,3 1.0 5.4 356 395 10.1 78 NNE 0,1 1.8 1.6 Oo1 354 3o6 385 12.4 96 NE 0,2 1.9 1.8 0o1 3.8 4 0o 432 12.3 95 ENE 0,2 2.1 2.8 0.4 5.3 5.5 591 14.3 111 E 0.3 2.6 1,4 4,0 4,3 467 10 1 78 ESE 0,2 2o0 o06 2o5 2.8 301 9.1 71 SE 0.3 2.3 0.7 350 353 352 8.9 69 SSE 0,2 2,2 1.3 356 308 411 11l1 86 S 0,4 3.2 5.4 0.2 6.8 7,2 777 12,9 100 SSW 0.2 4.8 6.5 0,8 12.1 12.3 1330 14,5 112 SW 0.3 5o7 7,1 1o0 1358 14 1 1524 14.1 109 WSW 0O3 5.4 6 6 1.0 12.9 13,2 1429 14o0 109 W 0.o3 36 2.9 0,2 6,8 7,2 774 12.1 94 WMNW 0.1 2.6 3.5 o05 6.7 6o8 732 14. 3 11 N1W 02 2,1 2o7 0,2 5,0 503 570 13 5 105 NNW 0. 1 12 2,2 0.1 2,6 2.7 295 12,5 97 Calm 0.5 __ 05 59 0.0 Totals 3.9 45 8 45C.1 4!-7 95.6 100o0 10824 Mean 12 9 100 39

N N NW NE NW NE )T / 15% a mph a>/,5% o amph W 0-5 E W t- \ 0 7 t E S W E S S TOLEDO MUNICIPAL AIRPORT DETROIT CITY AIRPORT TOLEDO, OHIO DETROIT, MICHIGAN Wind Instrument at Height of 47 ft. Wind Instrument at Height of 81 ft. Winter (Dec., Jan., Feb.) 1950-1954 Winter (Dec., Jan., Feb) 1957 N N NW< NE N NE /' j' 1 5% a mph 1 5% a mph W 271 E WE 0-6 g-_ E S S TOLEDO EXPRESS AIRPORT ENRICO FERMI POWER PLANT SITE TOLEDO, OHIO LAGOONA BEACH, MICHIGAN Wind Instrument at Height of 72ft. Aerovane at Height of 102ft. Winter (Dec., Jan., Feb.) 1957 Winter (Dec., Jan., Feb.) 1957 Fig. 13. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Winter Seasons, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Winter, 1956-1957. 40

TABLE XXIII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Enrico Fermi Site (Aerovane at height of 102 ft) 1 March 1957 - 31 May 1957 (Spring) Speed,,_ mph__ Total Mean Speed Wind 25 Total Observations Direction 0-3 4-12 1-24 and 4 and. of OverOver Over No. mph all Mean N 0.1 1.4 15 2.9 3.0 67 13,2 92 NNE 0.1 2,7 3.8 0 1 6.6 6.7 149 14.3 99 NE 0,1 2.1 4.8 0. 7.2 7 3 161 15.6 108 ENE 0.1 2.6 6.2 1 0 9,8 9.9 220 16.6 115 E 0.2 2,0 357 1 5 7-2 7.4 162 18.6 129 ESE 0.1 2.8 3.5 e 1 6.4 6.5 144 13.9 97 SE 0.1 2.3 2.2 0,2 4.7 4.8 105 13,7 95 SSE 0.2 40 102 0.1 5.3 5~5 120 10,3 72 S 0.3 2.8 1.4 4.2 4.5 99 11,0 76 SSW 0.2 2.8 2.2 0o1 5.1 5~3 114 12.4 87 SW 0,1 2.6 4,5 7,1 7.2 159 14o5 101 WSW 0.3 3.0 4,9 1.5 9.4 9.7 214 16 3 113 W 0.1 357 2.5 0o5 6.7 6,8 151 13.4 93 WNW O,1 351 5.6 8.7 8.8 193 14.6 101 NW 0,2 1.6 2.4 0,1 4.1 4o3 94 14.0 97 NNW 0,1 1.7 0.5 2,2 2.3 50 10,1 70 Calm 0,2 0.2 5 0.0 Totals 2o6 41,2 50.9 5-5 97-6 100o2 2207 Me an 14., 4 100 41

TABLE XXIV PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Express Airport (Wind instruments at height of 72 ft) 1 March 1957 - 31 May 1957 (Spring) Speed, mph Total M Mean Speed Wind 25 Total Observations M Direction 0-3 4-12 15-24 and 4 and. of OverDrcinOver Over % NO mph all Mean N 0,1 354 1.5 4.8 4,9 109 9o9 82 NNE 0,2 303 2,3 5.6 5.8 129 11,2 92 NE 003 4,0 lo7 507 5~9 131 L10o 83 ENE Ool 4,6 403 Ool 9.0 9.o 202 12.2 101 E 0.3 5 0 4o3 0.4 9o8 10o,1 22 12 5 103 ESE o04 352 0o6 358 4.2 92 8 6 71 SE 0.2 1.6 0o4 1.9 21 47 9.0 74 SSE 0ol 2.6 1.6 4o3 4.4 97 11.5 95 S 358 2.2 6.o 60o 133 10o9 90 SSW 2,2 2o0 o,1 4,3 4,3 94 12.9 107 SW 2,5 5.4 0,6 8.5 806 189 15.4 127 WSW 0.2 308 4o8 1.6 lOol 10o4 229 16.3 135 W Ool 4.9 2.8 0.2 8o0 8.1 178 11o9 98 WNW 0o2 4,3 352 7.6 7.7 171 114 94 NW 0.2 2.7 1.9 4 6 4,8 106 11, 0 91 NNW 0.2. 1.9 0 2o9 3.1 69 9,7 80 Calm 05 0_ _5 10 0 0 Totals 31o 5358 40o0 350 96o9 lOo0o 2208 Me an 12 1 100 42

TABLE XXV PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Detroit City Airport (Wind instruments at height of 81 ft) 1 March 1957 - 31 May 1957 (Spring) Speed, mph Total Speed Wind 25 Total Observations Ma _e Direction 0-5 4-12 13-24 and 4 and h % of OverOver Over T No, mph all Mean N 0.6 6,2 3.5 9.7 10o4 228 10 3 93 NNE 0.2 4. 3 15 5.8 6,0 132 10,2 92 NE 0,8 353 1o9 5.2 6o0 133 9o6 86 ENE 0.2 4.6 2.0 6o6 6.8 151 10o2 92 E 0.5 7.7 1l8 9,6 10.2 224 9.5 86 ESE 0.2 2.9 0.9 358 4.0 88 9o9 89 SE 0.6 3.8 0,5 4o3 4.9 109 7.4 67 SSE 0.1 2,4 0.9 354 354 76 9o3 84 S 0.2 7.1 1.5 8.6 8.9 195 9o0 81 SSW 1.7 1.6 3o 3 354 74 10.3 93 SW 1.4 358 1.0 6,2 62 137 15.0 1355 WSW 1.3 2o7 0.3 4.3 4.3 96 15.6 141 w o,4 3o8 4o0 0.4 8.3 8o6 192 13.0 117 WNW 0.1 2.1 14.7 0o3 7l 7o2 158 14o8 133 NW 0.2 352 3.4 6,7 6.9 152 12,2 110 NNW 1.2 1.0 2e1 2,1 47 12 1 109 Calm 0,7 0.7 16 0,0 Totals 4o8 571o 3557 2o1 95-0 100,0 2208 Mean 11ol 100 453

TABLE XXVI PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS, BIASED AND UNBIASED Detroit City Airport 1 March 1957 - 51 May 1957 (Spring) ~~_Wind. ~_ Total Observations Direction Biased Record. Unbiased Record Direction N..... N —No.' I'No, N 228 10.4 170 7.7 NNE 132 6.0 180 8 2 NE 133 6.0 119 5.4 ENE 151 6.8 179 8.1 E 224 10.2 189 8.6 ESE 88 4 0 118 5.3 SE 109 4,9 83 3.8 SSE 76 354 111 5 0 s 195 8.9 144 6~5 SSW 74 3.4 115 5 2 SW 137 6.2 104 4,7 WSW 96 4.3 123 5.6 w 192 8.6 168 7.6 WNW 158 7o2 196 8.9 NW 152 6.9 121 5~5 NNW 47 201 72 353 Calm 16 0.7 16 007 Totals 2208 100o0 2208 100.1 44

TABLE XXVII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Municipal Airport (Wind instruments at height of 47 ft) 1 January 1950 - 31 December 1954 (Spring Seasons).. -......S, m.... Total Speed, mph Total Mean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and of OverOver Over NO, mph all Mean N 0,3 2,9 1,0 3o9 4.2 468 9.1 72 NNE Ool 1.9 1.2 351 352 351 11o 87 NE 0.2 3o0 2,7 5o8 6o0 667 11.8 93 ENE 0.2 4.1 6.5 0.7 11.2 11.4 1258 14o6 115 E 0o4 3.8 350 0ol 6.9 703 811 11.4 90 ESE 0,2 2.2 0.7 350 352 350 9.4 74 SE 0.3 2o3 0.5 2.7 3.0 332 8 4 66 SSE 0,2 1.8 0.9 0.1 2o7 2o9 323 11.0 87 S 0.3 2,9 1.8 0o2 4.9 5 3 582 11.7 92 SSW 02 3.1 355 o04 7,0 7,2 796 1357 108 SW 0.4 4. 8 4.4 0.7 9o8 10 2 1127 1353 105 WSW 0.3 4,2 5o4 0.9 l0o4 10o8 1189 14o3 113 w 0o2 3.6 3o7 0o4 7.7 8,0 881 13o4 106 WNW o 3 2,4 4,7 0o4 7o6 7.8 865 14 9 117 NW 0.1 2o2 3.1 0.3 5o6 5o8 636 14o0 110 NNW 0.2 1.7 o.8 Oo1 2.6 2.8 307 10o6 83 Calm 0,9 0 9 97 0.0 Totals 359 46.9 4359 4o3 9_5.2 100.0 11040 Me an 12.7 100 45

N N NW -,MNE N1/ NE'15% a mph r 15%amph W E W E S S TOLEDO MUNICIPAL AIRPORT DETROIT CITY AIRPORT TOLEDO, OHIO DETROIT, MICHIGAN Wind Instrument at Height of 47ft. Wind Instrument at Height of 81 ft. Spring (Mar., Apr., May) 1950-1954 Spring (Mar., Apr., May) 1957 N N NW NE NW NE W ~b/ 15% 8 mph 15% mph 1 0.5'- E W ~ E S S TOLEDO EXPRESS AIRPORT ENRICO FERMI POWER PLANT SITE TOLEDO, OHIO LAGOONA BEACH, MICHIGAN Wind Instrument at Height of 72ft. Aerovane at Height of 102ft. Spring (Mar., Apr., May) 1957 Spring (Mar., Apr., May) 1957 Fig. 14. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Spring Seasons, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Spring, 1957. 46

TABLE XXVIII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Enrico Fermi Site (Aerovane at height of 102 ft) 1 June 1957- 31 August 1957 (Summer) Speed, mph Total Mean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and N.. h % of OverOver Over NO. mph all Mean N 0o3 4.0 0o3 4.3 4.6 101 8o2 79 NNE 0.6 351 lo. 4.2 4.8 106 9,6 92 NE 0.1 1.8 2.8 4.6 4.7 105 14. 0 135 ENE 0,2 352 3o4 6.6 6.8 150 13.0 125 E 0,5 3o6 1.7 553 5.8 129 10.5 101 ESE o05 2 9 2.0 4.9 5.4 120 11.4 110 SE 0.3 3.5 1.4 4.9 5o2 114 10.5 101 SSE 0,1 6.7 1.2 7 9 8o0 177 9.4 90 s 0.2 5'6 1.4 7.0 702 159 9,8 94 SSW 0,3 4,9 1.7 6.6 6o9 152 10o3 99 SW 0.4 5o2 2.0 7,2 7.6 167 10o4 100 WSW 03, 5.1 1,9 7.0 7.3 163 10.5 101 W. 5 5.4 2o0 01 7.5 8o0 177 10.4 100 WNW 0.3 5l. 1,6 0.2 6,9 7~2 159 10o7 103 NW 0.1 4,2 0.7 4.9 5o0 111 9,3 89 NNW 0.3 4.4 0,5 4.9 5.2 116 8.6 83 Calm 0.1 _ 1 2 0.0 Totals 5o1 68.7 25o7 0o3 94.7 99.8 2208 Mean 10,4 100 47

TABLE XXIX PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Express Airport (Wind instruments at height of 72 ft) 1 June 1957 - 31 August 1957 (Summer) S peed, mh Total Wind 25 Total ObservationsSp Direction 0-3 4-12 13-24 and 4 and of Over-,,,,,,Over Over NO. mph all Mean N 0.6 5.8 1.2 7.0 7.6 167 9.1 94 NNE o06 4,7 0o8 5.5 6.1 136 8.7 90 NE 0.5 3.9 1.0 4.9 5.4 121 9.3 96 ENE 0.6 4.8 1.5 6.3 6.9 152 9.7 100 E o.6 4.7 1.1 5.8 6.4 142 9.2 95 ESE 0,4 3.8 0.2 4,0 4.4 97 7.9 81 SE 0.5 2,4 0.1 2.5 350 67 7.1 73 SSE 0.2 2.3 0.2 2.5 2.7 61 8.3 86 S 0.3 4.9 1.1 6.o 6 3 140 9,6 99 SSW 0.4 4,2 2,0 6.2 6.6 145 10,8 111 SW 0 3 5o7 351 0.1 8,9 9,2 203 11.5 119 WSW 0.6 6o 6 3o8 0.1 10.5 11.1 246 11.5 119 W 0,2 4.2 2,4 6.6 6.8 150 11.4 118 WNW 0.4 5.1 1.8 6.9 7.3 161 10.3 106 NW 0.7 2,7 0.6 3.3 4.0 90 8,5 88 NNW 0o4 357 0.5 4.2 4.6 102 8.7 90 Calm 1.3 1.3 28 0 0 Totals 8,6 69.5 21.4 0,2 91.1ol 99.7 2208 Mean 9o7 100 48

TABLE XXX PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Detroit City Airport (Wind instruments at height of 81 ft) 1 June 1957 - 31 August 1957 (Summer) Speed, mph TotalMean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and N. m of OverOver Over T NO. mph all Mean N 1,6 6.6 1.6 8.2 9.8 216 8.6 84 NNE 0.6 4.3 1.4 5.7 6 3 142 9.7 95 NE loO 353 007 4.0 5~0 109 8.3 81 ENE 0.2 535 1,3 4.8 5.0 110 10.5 103 E 0.8 5.5 1.1 6.6 7.4 1614 8.8 86 ESE 0.1 3.7 0.5 4o2 4.3 94 9,2 90 SE 0.9 3.8 Oo3 4. 1 5o0 110 7.5 74 SSE 0.2 1.4 0.5 1.9 2.1 46 9o6 94 S 0o6 8.8 2.3 11.1 11.7 259 9.7 95 SSW 2.4 1.6 4.-0 4,0 88 12 3 121 SW 0,5 3 6 2.6 6.2 6.7 149 11 6 114 WSW 0o1 1.7 2,2 3.9 4 0 86 13o8 135 W 0.6 4.7 4,2 0.2 9.1 9o7 212 12.4 122 WNW 0 1 2.8 2o2 0,7 5,7 5.8 126 14o6 143 NW 0.6 4.5 2,2 6o7 7o 3 162 10 5 103 NNW 0.4 2,6 lol 3.7 4.1 91 lOl 99 Calm 2.0 2.0 l44 0,0 Totals 10.5 63.2 25,8 0.9 89.9 100.2 2208 Mean 10.2 100 49

TABLE XXXI PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS, BIASED AND UNBIASED Detroit City Airport 1 June 1957 - 31 August 1957 (Summer) Total Observations Wind Biased Record. Unbiased Record Direction N. No.. N0. _,, _] No... N 216 9.8 181 8.2 NNE 142 6.3 166 7.5 NE 109 5.0 101 4.6 ENE 110 5.0 121 5.5 E 164 7.4 143 6.5 ESE 94 4.3 120 5.4 SE 110 5.0 81 3.7 SSE 46 2.1 86 3o9 s 259 11.7 1714 7o9 SSW 88 4.0 169 7.7 SW 149 6.7 109 4.9 WSW 86 4.0 120 5.4 W 212 9.7 167 7.6 WNW 126 5.8 173 7.8 NW 162 7.3 128 5 8 NNW 91 4.1 125 5.7 Calm 44 2,0 144 2.0 Totals 2208 100.2 2208 100.1 50

TABLE XXXII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Municipal Airport (Wind instruments at height of 47 ft) 1 January 1950 - 31 December 1954 (Summer Seasons) Speed, mph Total Mean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and | N mph of OverOver Over. No. mph all Mean N 0.7 3.3 0.6 359 -.6;09 - 91 NNE 0.3 2.4 08 352 355 391 9,1 106 NE 0.6 3.7 1.5 5.0 5.6 619 9 1 106 E NE 0,6 4.9 2,2 7.1 7.7 849 9.9 115 E 0.7 4.1 o06 14o7 544 604- 7.7 90 ESE 0.4 2.5 0ol 2.6 3,0 330 6.4 74 SE 0.7 353 0 1 354 4.1 456 6.0 70 SSE 0,6 2.9 0,5 352 358 416 6.7 78 S 0.7 5.2 0.7 5.9 6.6 727 7.6 88 SSW 0.7 6.6 2.4 0.1 9.1 9.8 1086 9.7 113 SW 1.1 90 53.1 0.1 12.2 13 3 1463 9.1 106 WSW 0o7 5.5 2 6 0 1 8.2 8.9 973 9.7 113 w 0o8 4.1 1.4 5.5 6.3 705 8,8 102 WN1W 0.5 38 2,1 5e9 6 4 721 10.5 122 NW 0o7 2.9 1 3 4,2 4 9 545 9.3 108 NNW o 5 2 o2 0.8 3.0 3.5 394 8.8 102 Calm 2,3 2.3 252 Oo0 Totals 12.6 66.4 20.4 0.3 87.1 99.7 11040 Me an 8,6 100 51

N N N WIN N E N W d ~^^^N E!NvV>. ^ 15% a mph / 15% a mph W 2.3 E W _ 0- ~ E S S TOLEDO MUNICIPAL AIRPORT DETROIT CITY AIRPORT TOLEDO, OHIO DETROIT, MICHIGAN Wind Instrument at Height of 47ft. Wind Instrument at Height of 81ft. Summer( Jun., Jul., Aug.) 1950- 1954 Summer( Jun., Jul., Aug.) 1957 N N NW NE NW ~NE N/ /- ~1 5% m ph 15% A mph 10 w 1 3 E W 0 E W( E W E s S S TOLEDO EXPRESS AIRPORT ENRICO FERMI POWER PLANT SITE TOLEDO, OHIO LAGOONA BEACH, MICHIGAN Wind Instrument at Height of 72ft. Aerovane at Height of 102ft. Summer(Jun., Jul., Aug.) 1957 Summer( Jun., Jul., Aug.) 1957 Fig. 15. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Summer Seasons, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Summer, 1957. 52

TABLE XXXIII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Enrico Fermi Site (Aerovane at height of 102 ft) 1 September 1957 - 30 November 1957 (Fall) Speed mph TotalMean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and.. h % of OverOver Over NO mph all Mean N 0.1 3.8 1.0 4.8 4,9 103 9,8 81 NNE 0.1 2,1 0,3 2,4 2.5 52 8.8 73 NE 0,0 2.1 3,6 5o7 5.7 121 14 5 120 ENE 0.1 2.6 351 5.7 5,8 121 13.5 112 E 0.0 2.0 0 9 Oo 1 30 350 64 11.6 96 ESE 0.2 358 1.0 4.8 5e0 105 9.7 80 SE 0,1 1.7 0,8 0.3 2,8 2,9 60 12.5 103 SSE o01 356 1.7 0.4 5.7 5.8 122 12.2 101 S 0.1 5o4 1,6 5o0 5 1 108 11.1 92 SSW 0 3 5.2 3, 2 0.0 84 8.7 186 13o5 112 SW 0,3 4.8 3.8 0.2 8,8 9.1 193 12,7 105 WSW 0.4 4.7 5.4 2,3 12o4 12.8 267 16.0 132 W 0.2 3.1 2.0 5,1 5.3 112 11.6 96 WNW 0.1 5.1 1.5 6.6 6.7 140 10.2 84 NW 0,2 4.8 1,9 6.7 6o9 147 10.6 88 NNW 0o1 7o3 1.9 9,2 9.3 19.6 10.0 83 Calm 053 0 3 7 0 0 Totals 2.7 60.1 3357 353 97.0 99.8 2104 Me an 12,1 100 53

TABLE XXXIV PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Express Airport (Wind instruments at height of 72 ft) 1 September 1957 - 30 November 1957 (Fall) Speed, mph TotalMean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and of OverOver Over % N mph all Mean N o,08 8o2 0,5 8,7 9z5 208 8,0 81 NNE 0.3 3 8 0o4 4l2 4 5 98 8,5 86 PiE OO4 4e5 0 5 5o0 5c4 118 8.4 85 E NE 0.3 351 O 8 3.9 4.2 91 95 96 E 0, 3 4,3 o.8 5.1 54 117 922 93 ESE 0o4 1,6 1 6 2,0 45 6,7 68 SE 0,2 2,4 O0 2 4 2.6 57 7a7 78 SSE o o 530 0o9 3.9 3:9 86 104 105 s 0.7 5.8 1.6 7-4 8 1 177 9.6 97 SSW 0 3 4 5 o15.1 65 1 6 4 139 10. 106 sw 0O1 6.5 4.4 0,3 112 1153 247 12 6 127 WSw Oo1 60o 357 0o6 10o3 10o4 229 12o8 129 w 0O.4 4 3 2o5 0 3 7. 175 16 12 O0 121 WNW O 3 4 o 0.9 4 o9 5o2 11 9o 96 NW o6 66. o6 69 7 5 164 8,3 84 NNW o2 46 06 o6 52 5o4 118 8.9 90 Calm 0.5 _ 005 12 0 _ Totals 539 72.9 19 7 1 3 93e9 9938 218,L Mean 9.9 100

TABLE XXXV PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Detroit City Airport (Wind instruments at height of 81 ft) 1 September 1957 - 30 November 1957 (Fall) Speed, mph TotalMean Speed Wind 25 Total Observations Mnp Direction 0-3 4-12 13-24 and 4 and No m % of OverOver Over. No, mph all Mean N 1.7 7.7 2o7 10o4 12 1 264 9.4 81 NNE 0.5 2.2 0.3 2,5 350 66 7.8 67 NE 1.0 2.9 0.8 3.7 4.7 103 8.5 73 ENE 0o2 2,1 007 2.8 3.0 67 10l0 86 E.l4 2.8 005 353 4,7 102 7.1 61 ESE 0.. 1.5 1.6 l9 l 7 6 66 SE 0o4 3.2 0.6 3.8 4,2 91 9,0 78 SSE 0.2 352 0.7 0.1 4.0 4,2 90 9.8 85 S 0.3 6.0 2.4 0,1 8,5 8.8 191 10.8 93 SSW 0.2 1.6 2.5 4.1 4,3 96 1357 118 SW 0,3 4.6 6.9 1,5 1350 13.3 287 15,7 135 WSW 0.1 2o7 4.2 0.3 7,2 7~3 159 14.8 128 W 0,2 3,2 3.1 0ol 6.4 6 6 143 12.9 111 WNW 0.2 2,1 2.9 0,3 5,3 5 5 120 14. 3 123 NW 0o5 4.9 3.6 0o2 8 7 9o2 200 12.1 104 NNW 0.5 2,6 5e1 0ol 5.8 6e3 137 12,7 110 Calm 1, 2 1.2 27 0.0 Totals 9,2 53.3 35.1 2,7 91,1 100.3 2181Mean 11 6 100 55

TABLE XXXVI PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS, BIASED AND UNBIASED Detroit City Airport 1 September 1957 - 30 Novermboer 1957 (Fall) Wind. Total Observations DWi rind Biased Record Unbiased Record Direction No. No. N 264 121 195 8.9, NNE 66 3 0 102 4 7 NE 103 4.7 78 3 6 ENE 67 3.0 87 4,0 E 102 4 7 79 3 7 ESE 41 19 77 3 5 SE 91 4,2 70 3.2 SSE 90 4,2 92 4,2 S 191 8t8 145 6,6 SSW 96 4 3 160 7 3 SW 287 1353 226 10.3 WSW 159 753 210 9 6 W 143 6.6 123 5%6 W1W 120 5 5 150 6 o 0 NW 200 9.2 165 7. 6 NNW 137 6.3 218 10 0 Calm 27 1 2 27 1 2 Totals 2184 100 3 2184) 100 0

TABLE XXXVII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Municipal Airport (Wind instruments at height of 47 ft) 1 January 1950 31 December 1954 (Fall Seasons) Speed, mph TotalMean Speed Wind 25 Total Observations, Direction 0-53 4-12 13-24 and 4 and of OverDrco Over Over NO mph all Mean N 0o 6 3.0 09 3o9 4o5 493 8.7 85 NNE 0.2 1.7 1.3 350 3 2 347 11 3 110 INE 0.4 2.4 1.5 3.9 4.3 478 10o4 100 ENE 0.4 2.o 1.2 53. 357 403 10o0 97 E o06 2,6 Oo5 3.1 357 405 7.5 73 ESE 0.2 1.6 0.1 1.7 1.9 221 7e1 69 SE 0. 6 25 0.1 2o6 3 3 355 6 3 61 SSE 0.5 2 5 0 5 0.1 3.1 3o6 395 8o6 84 S 0.7 5c8 2.0 0.1 7.9 8 6 940 9.8 95 SSW 0,6 7o9 5.4 0o2 13o5 14 o 1556 11,4 111 SW O 9 9.4 5.2 0.6 15o2 16.1 1745 11.3 110 WSW 0.8 5o5 3o7 0 3 9.5 10o3 1122 11.2 109 W 0.5 3.6 1.6 0.1 5.3 5e8 630 10.0 97 WNW 0, 352 2.8 o.1 6,1 6.4 703 12.1 118 nrW o.6 2.3 2.6 0.1 5.0 5.5 606 12 1 118 NNAT O 02 1o7 1.o3 30 3.2 362 11o2 109 Calm 1 5 _1.5 159 00 _ Totals 9 6 57.8 30.7 1.6 90o1 99.7 10920 Mean 10,53 100 57

N N NW< JNE NW< VNE 15% mph 15% &mph 10 10 W 5 \E W E SW< SE ISW S S TOLEDO MUNICIPAL AIRPORT DETROIT CITY AIRPORT TOLEDO, OHIO DETROIT, MICHIGAN Wind Instrument at Height of 47ft. Wind Instrument at Height of 81ft. Fall (Sept., Oct., Nov.) 1950- 1954 Fall ( Sept., Oct., Nov.) 1957 N N NW -F ^ \NE N J ^NE 15% a mph 15% a mph 10 10 W - - 0. E W 0- - E W E W E S S TOLEDO EXPRESS AIRPORT ENRICO FERMI POWER PLANT SITE TOLEDO, OHIO LAGOONA BEACH, MICHIGAN Wind Instrument at Height of 72 ft. Aerovane at Height of 102ft. Fall (Sept., Oct., Nov.) 1957 Fall (Sept., Oct., Nov.) 1957 Fig. 16. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Fall Seasons, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Fall, 1957. 58

TABLE XXXVIII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Enrico Fermi Site (Aerovane at height of 102 ft) 1 December 1956 - 30 November 1957 (Annual Summary) Speed, mph Totaln Mean Speed Wind 25 Total Observations,p Direction 0-3 4-12 13-24 and 4 and % mp of OverOver Over No, mph all Mean N 0.1 2,7 1.0 0.1 3.8 3.9 349 11.1 89 NNE 0.2 23. 1.8 0.1 4.2 4 4 383 12.5 100 NE 0.1 1.8 3.8 0.3 5.9 6.0 507 15. 3 122 ENE 0.2 2.4 3.5 0.3 6.2 6,4 551 14.5 116 E 03. 2.2 1.9 0.4 4.5 4,8 409 14,1 113 ESE 0.2 2.9 1,9 0.1 4.9 5,1 433 11.8 94 SE 0.2 2,3 1.3 0.1 3.7 3.9 342 11.9 95 SSE 0.1 3.9 1.2 0.1 5,2 5.3 465 10.6 85 S 0.2 3.4 1.6 0.1 5.1 5o3 455 11.0 88 SSW 0.2 3.9 3.2 0,2 7 3 7.5 645 12.6 101 SW 0.3 4.1 4.3 0.2 8.6 8.9 759 13.2 106 WSW 0.3 5.1 4.8 0o9 10.8 11.1 959 14.1 113 W 0.3 4.4 2.7 0.2 7,3 7.6 663 11.9 95 WNW 002 4.6 3,2 0.1 7.9 8.1 705 12,2 98 NW 0.o3 3o9 1.0 0.1 5.9 6.2 535 11.0 88 NNW 0.2 4.2 1,3 5.5 5.7 493 10.2 82 Calm 005 0.3 26 0.0 Totals 3.7 54.1 39.4 3,3 96.8 100.5 8679 Mean 12.5 100 59

TABLE XXXIX PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Express Airport (Wind instruments at height of 72 ft) l.-December 1956- 30 November 1957 (Annual Summary) Speed, mph TotalMean Speed Wind 25 Total Observations Se Direction 0-3 4-12 13-24 and 4 and N h of OverOver Over % NQO mph all Mean N 0.5 5.1 1,3 OoO 6.4 6.9 602 9.6 88 NNE 0.3 35.5 12 0.0 4.7 5o0 443 10.2 94 NE o04 3.8 1.1 4.9 5.3 455 9.7 89 ENE 0.4 3.6 1.8 0.0 5~4 508 513 11.0 101 E o04 4.1 1,8 0.1 6.0 6o4 558 10o9 100 ESE 0.4 2,7 0,3 350 3,4 295 8.1 74 SE 0.3 2.1 0,1 2,2 2o5 222 7.7 71 SSE 0.2 2,6 0.7 0.0 3.3 355 315 909 91 S 0.3 4.7 1 7 0.0 6.4 6.7 592 10.3 95 SSW 0.2 3.4 2.2 0 1 5,7 5.9 526 12,0 110 SW 0,2 5.0 48 03 10.1 10.3 897 1303 122 WSW 0.3 6,3 4.9 0.6 11.8 12 l 1060.15-1 120 W 0,2 4.7 2.6 01. 7,4 7 6 667 11.8 108 WNVW 0.2 4 5 2,0 6 5 6. 7 587 10e9 100 NW 0 5 4.1 1.2 0 o 0 5.3 5,8 508 9.7 89 NNW 03. 3.5 0,9 4 4 4o7 412 9.5 87 Calm 1,2 2____ 108 00 Totals 6,3 65.7 28.6 1,2 9355 98,8 8760 Mean 10 9 100 60

TABLE XL PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Detroit City Airport (Wind instruments at height of 81 ft) 1 December 1956 - 30 November 1957 (Annual Summary) Speed, mph TotalMean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and of OverOver Over NO mph all Mean N 1.2 6.8 2.9 9.7 10.9 95 101Oo 89 NNE 0o4 3.3 1.1 4.4 4.8 428 9.9 87 NE 0.8 2.7 1.0 3.7 4.5 394 9ol 80 ENE 0 2 3.2 1.1 4 3 4.5 397 10.3 90 E 0.9 4.9 o09 5.8 6o7 583 8.7 76 ESE 0.2 2.4 0.4 2.8 350 260 8.9 78 SE 0.5 353 0.4 3.7 4,2 368 8,2 72 SSE 0.2 2~6 o06 352 3.4 297 9~6 84 S o0,4- 6.8 2.1 8o9 9 3 813 10.1 89 SSW 0.1 2o1 2,0 4 1 4o2 363 12o9 113 SW 0.2 357 5.1 0.5 9o3 905 830 14o5 127 WSW 0.1 2o2 3.2 0.2 5 6 5o7 492 14o5 127 W 0.3 4,4 4o3 0.1 8.8 9.1 800 13.0 114 WNW 0o1 2,4 359 0,4 6,7 6,8 595 15o1 133 NW o05 4,2 352 01o 7e5 8o0 700 12o0 105 NNW 0.3 2o1 2o0 4 1 4o4 387 12,3 108 Calm 1.2 1, 2 102 0.0 Totals 7.6 57.1 34,2 1.3 92 6 100.2 8760 Me an 11.4 100 61

TABLE XLI PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS, BIASED AND UNBIASED Detroit City Airport 1 December 1956- 30 November 1957 (Annual Summary) TT.~~Wind, _ Total Observations Windect. Biased Record. Unbiased Record Direct ion _- No.. No. % N 951 10.9 739 8c4 NNE 428 4.8 565 6.4 LE 394 4,5 3150 3,9 ENE 397 4,5 458 5.2 E 583 6.7 490 5.6 ESE 260 350 325 3.7 SE 368 4.2 281 3.2 SSE 297 3,4 419 4.8 S 813 9.3 599 6.8 SSW 363 4.2 597 6,8 SW 830 9.5 632 7,2 WSW 492 5 7 671 7.7 w 800 9.1 680 7,8 WNW 595 6.8 717 8,2 NW 700 8,0 571 6 NNW 387 4,4 576 6.6 Calm 102 1,2 102 1,2 Totals 8760 100,2 8760 100.0 69

TABLE XL II PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Municipal Airport (Wind instruments at height of 47 ft) 1 January 1950 - 31 December 1954 (Five-Year Summary)..Seed mph.Total Speed,_ mph __ Total Mean Speed Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and mph of OverOver Over N mph all Mean N 0.5 2,9 Oo9 358 4.3 1865 8.8 79 NNE 0.2 2,0 1.2 352 354 1474 10.9 98 NE 0o4 2~8 18 4.6 500 2196 10o8 97 ENE 0.3 35.3 32 0,2 6.7 7.0 3101 12,6 113 E 0o5 3.3 lo4 4_7 592 2287 9,5 86 ESE 0,3 2.1 0.4 2,5 2.8 1202 8.1 73 SE 0,5 2 6 0.3 2.9 35o 1495 7o3 66 SSE 0,3 2.4 0.7 o01 3.2 3.5 15145 9,2 83 s 0o5 4,2 2,0 ol 6.3 6.8 3026 10 o4 94 SSW 0.4 5.6 4,, 0o4 10o5 10o9 4768 12.3 111 SW 0.7 7,2 4 9 0.5 12.6 1353 5859 119 107 WSW 0.5 51l 4.6 0o5 102 107 4713 125 11 W 0,5 357 2.4 0,2 653 6,8 2990 11.3 102 WNW 0,3 3.0 3.3 0.2 6.5 6,8 3021 1351 118 NW 0,4 2,4 2,4 0.1 4,9 5.3 23557 123 111 TNNW 0,5 l7 1.1o 2o8 351 1358 l0o6 95 Calm 1.3 1.3 567 0.0 Totals 7,9 54.53 355 2.3 91.7 99.6 43824 Mean 11o l 100

N N NY y NE N W NE 15% a mph 15% 8 mph SW E W E S S TOLEDO MUNICIPAL AIRPORT DETROIT CITY AIRPORT TOLEDO, OHIO DETROIT, MICHIGAN Wind Instrument at Height of 47ft. Wind Instrument at Height of 81ft. Five Year Summary 1950-1954 Annual Summary 1957 N N NW< IN NE — 1-NW NE 15Eo/o% mph / 1%a mph 10I0 sW E WE ~ \ E S S TOLEDO EXPRESS AIRPORT ENRICO FERMI POWER PLANT SITE TOLEDO, OHIO LAGOONA BEACH, MICHIGAN Wind Instrument at Height of 72ft. Aerovane at Height of 102ft. Annual Summary 1957 Annual Summary 1957 Fig. 17. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Toledo Municipal Airport, Five-Year Summary, 1950-1954; Detroit City Airport, Toledo Express Airport, and Enrico Fermi site, Annual Summary, 1956-1957. 64

discussion of these records in the second progress report is considered adequate. It should be noted that the Detroit City Airport record which appears in the windroses of Figs. 13-17 is the record as it was reported and as it appears in Tables XX, XXV, XXX, XXXV, and XL, E, ESE, SE, SSE, and S combined-In Table XLIII the percentage frequency of these winds at the site from 1 December 1956 to 30 November 1957 is compared to those for the same period at Toledo Express Airport, Detroit City Airport, and to the 5-year period 1950-1954 at Toledo Municipal Airport, With the exception of summer when the influence of the lake breeze is strong (see Part III) the plant site is not unlike Toledo and Detroit. Judging from the annual summary in the last line of Table XLIII, it was a fairly typical year. TABLE XLIII COMBIINED PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS FROM TEE E, ESE, SE, SSE, AND S, 1 DECEMBER 1956 - 30 NOVEMBER 1957, AT TEE ENRICO FERMI SITE, TOLEDO EXPRESS AIRPORT, AND DETROIT CITY AIRPORT, ARD 5-YEAR AVERAGE AT TOLEDO MUNICIPAL AIRPORT, Detroit City Enrico Fermi Toledo Express Detroit City Toledo Municipal Airport Site Airport Airport (5-yr. Avg.) (approximation) Winter 15.5 18.6 18.6 21.4 Spring 29.3 26.8 29.2 21.7 Summer 51 6 22.8 27.4 22.9 Fall 21.8 22.0 21.2 211ol Annual 24.4 22.5 24.1 21.7 W, WNW, NW, NNW, N, and NNE combined-Winds from these directions are summarized in the same manner in Table XLIV. Here it appears as if Toledo is more representative of the plant site than Detroit. Winds from this sector were more frequent during this year than during the 5-year average and one may interpret the departure from the 5-year means as a crude measure of the amount of variation one may expect above and below the mean. ENE-IMonroe -.Winds from this direction are summarized in Table XLV. Again it appears as if Toledo is more representative of the plant site than Detroit. It was a typical year even to the spring maximum, SSW —Detroit River communities —Winds from the SSW are summarized in Table XLVI. For this wind direction, Detroit appears to be more representative of the plant site than Toledo. Frequencies at Toledo Express Airport are less than the 5-year average in each season which may indicate either an abnormal year or some minor difference in winds at the two airports. Another year of data may help to throw light on this feature.

TABLE XLIV COMBINED PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS FROM THE W, WNW, NW, NNW, N, AND NNE, 1 DECEMBER 1956 30 NOVEMBER 195T AT ENRICO FERMI SITE, TOLEDO EXPRESS AIRPORT, AND DETROIT CITY AIRPORT, AND 5-YEAR AVERAGE AT TOLEDO MUNICIPAL AIRPORT, Enrico Fermi Toledo Express trotToledo Municipal Airport Site Airport r. o Airport (5.-yr. Avg ) (approximation').. -Winter 40o8 36.4 49,1 29.2 Spring 30.7 34 4 41.2 31.8 Summer 34.8 36.4 42.2 29.2 Fall 35.6 39,6 42.8 28.6 Annual 35.9 36.7 4359 29.7 TABLE XLV PERCENTAGE FREQUENCY OF OCCURRENCE OF ENE WINDS, 1 DECEMBER 1956 - 30 NOVEMBER 1957, AT ENRICO FERMI SITE, TOLEDO EXPRESS AIRPORT, AND DETROIT CITY AIRPORT, AND 5-YEAR AVERAGE AT TOLEDO MUNICIPAL AIRPORT. Detroit City Enrico Fermi Toledo Express trot t Toledo Municipal Airport Site Airport approximation) Airport (5 yr. Avg ) Winter 350 351 353 5.3 Spring 10.1 9.1 8.1 11.4 Summer 6.8 6.9 5.5 7.1 Fall 5.8 4.2 4.0 3.7 Annual 6,4 5e8 5o2 7.0 TABLE XLVI PERCENTAGE FREQUENCY OF OCCURRENCE OF SSW WINDS, 1 DECEMBER 1956 - 30 NOVEMBER 1957, AT ENRICO FERMI SITE, TOLEDO EXPRESS AIRPORT,.AND DETROIT CITY AIRPORT, AND 5-YEAR AVERAGE AT TOLEDO MUNICIPAL AIRPORT. Detroit City Enrico Fermi Toledo Express Airport Toledo Municipal Site Airport (approximati-.,) Airport (5 —yr. Avg.) Winter 9.7 6,9 7o2 12o1 Spring 5,6 4,3 5o2 7.2 Summer 6o9 6.6 7,7 9.1 Fall 8.7 6.4 7.53 14.1 Annual 7.5 5o9 6.8 10,9 66

SW and WSW-Ontario shores-Winds from the SW and WSW are summarized in Table XLVII. Toledo appears to be very representative of the plant site except in summer when the lake-breeze effect apparently diverts some of the SW and WSW winds to the quadrant E through S. TABLE XLVII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS FROM THE SW AND WSW, 1 DECEMBER 1956 - 30 NOVEMBER 1957, AT THE ENRICO FERMI SITE, TOLEDO EXPRESS AIRPORT, AND 5-YEAR AVERAGE AT TOLEDO MUNICIPAL AIRPORT. Detroit City Enrico Fermi Toledo Express rport Toledo Municipal Site Airport (approximation) Airport (5-yr. Avg.) Winter 24.8 28.4 19.1 26o7 Spring 17.2 19o0 10.3 21.0 Summer 14 9 20e 3 10.3 20.4 Fall 21.9 21.7 19.9 26.4 Annual 20.0 22.4 14.9 24,0 35 WIND SPEED AT THE ENRICO FERMI SITE The analysis of wind speeds has centered on obtaining evidence of special effects due to the lakeo These effects are related to the relative smoothness of the lake which reduces friction and to the temperature of the lake which results sometimes in inversions and other times in strong lapse rates over the lake. The following description of the analytical technique is taken directly from the second progress report. "Figure 12 indicates that winds from the sector bounded by NE through SSE have a water trajectory prior to reaching the aerovane at the plant site, whereas, for all other directions at the plant site, and without exception at Detroit and Toledo, the winds experience a land trajectory. Direct comparisons between wind speeds for corresponding directions at three stations are meaningless because of different heights of anemometer exposure and differences in instrumentationo However, if mean wind speeds for each direction are first expressed as a percentage of the overall mean wind speeds for all directions, comparisons may then be made. For example, during the spring of 1957 the mean wind speed at the plant site was 14.4 mph. The mean wind speed for WNW winds was 14o6 mph or 101 percent of 14.4. Computations of this sort have been made for all wind directions for the three stations." These appear as the last column of Tables XVIII - XLII except Tables XXI, XXVI, XXXI, XXXVI, and XLIo The analysis is brought to a focus in Figso 18-22, In these figures the wind speed in percent at the Enrico Fermi site is compared to a combined wind speed in percent for Detroit and Toledo, for each of the seasons and for the year as a whole. The directions which represent a water trajectory are shown 67

150 i I I I — 150 WATER TRAJECTORY, AT MONROE W. 130 0. 120 Qz 401/ \ / \ \ \ \100 ___ / co / Z 70 TOLEDO z o 60 — x... M ON ROE N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Fig. 18. Mean wind speed at the Enrico Fermi site and Detroit-Toledo combined, for 16 directions, expressed as a percentage of the overall mean winter wind speed, 1956-1957.

150 140 ___ ___ WATER TRAJECTORY z130 (.3 /!_ 0120 a. Z I10 / /- 0 LLI / \ _\ w 100 X a. 8 0 ---- ---- v -- A I..... 80 - I I I I i LU 7 0 ~x,, x.....DETROIT TOLEDO 60 -x... MONROE 50N N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Fig. 19. Mean wind speed at the Enrico Fermi site and Detroit-Toledo combined, for 16 directions, expressed as a percentage of the overall mean spring wind speed, 1957.

150. —i WATER TRAJECTORY 140 -- - AT MONROE 130 I- - w 120 I -- z /00 o ud 9 0 _z 7, _ I I. L/ l __ ______ _ <W DETROIT TOLEDO 60 - _ - --- ----- MONROE 50 N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Fig. 20. Mean wind speed at the Enrico Fermi site and Detroit-Toledo combined, for 16 directions, expressed as a percentage of the overall mean summer wind speed, 1957.

150 —- -- - 140 WATER TRAJECTORY AT MONROE 130 z 120 W 110 -- 0 10/....I " % / / \ \ /' " \^x _,oo___r: ___ \_ /- ______ - ETRO 2 70 9 ~. DETROT / M o x 70 r__ TOLEDO 60 ---— x —— MONROE 50I I N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NW Fig. 21. Mean wind speed at the Enrico Fermi site and Detroit-Toledo combined, for 16 directions, expressed as a percentage of the overall mean fall wind speed, 1957.

150 - -- - WATER TRAJECTORY 140' - AT MONROE I —Z 130 w 120 a.I z 120 _ — --...... o_ I 1 aW / w AK -- -' /;"T99~~~~~~~~~ t $ 80 ___ ________ \____ I /___-__ ___ ___ ___ ___ 80 z ____ DETROIT 70 -. TOLEDO 60- -- x —-- MONROE 50I I I N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Fig. 22. Mean wind spedd at the Enrico Fermi site and Detroit-Toledo combined, for 16 directions, expressed as a percentage of the overall mean annual wind speed, 1956-1957.

on the figures. It is evident that winds which are off the lake are relatively stronger at the plant site than the same winds at Detroit and Toledo. This effeet had been noted in winter and spring in the second progress report but there was speculation as to whether the same effect would be noted in all seasons. In general this appears to be the case except for SSE winds in spring and summero The factors underlying the effect have been referred to in the first paragraph of this sectionn The reduced frictional drag on the air crossing the lake will tend to make winds stronger. However, if the lake temperature is cold enough relative to the air temperature to produce an inversion, the resultant decreased downward transport of momentum will tend to make the winds weakero This will be recognized as the circulation inversion, discussed earlier in Section 4 of Part I which, it was pointed out, is most likely to occur with SSE winds and in the spring and early summero It thus appears that the tendency of inversions todecrease wind speeds will dominate the tendency of reduced frictional drag to increase winds when both factors operate as they frequently do in spring and early summero A reasonable extrapolation of these results would be the expectation that winds from land to water at the plant site will tend to accelerate as they move across the lake except when one can predict the development of an inversion over the lakeo 75

IIIo LAND- AND LAKE-BREEZE EFFECTS AT LAGOONA BEACH 1. INTRODUCTION Lagoona Beach is situated at the western end of Lake Erie, The general terrain, which is very flat in all directions, is overgrown by a mixture of tall grass, low bushes, and occasional clumps of trees about 40 ft high. Figure 12 illustrates the general topography of the area. The general bearing of the shoreline at this end of the lake is NE-SW but in the immediate vicinity of the site southerly winds will cross a point of land. As aresult only those winds which blow from the sector NE through SSE are considered to reach the site directly from the lake. Following a preliminary investigation into the air-pollution climatology of the region3, an investigation based on data from two first-order Weather Bureau stations some 25 to 30 miles from the site, it was decided to conduct an on-the-spot study of the local climatology. The possibility of finding special lake effects not present at the abovementioned Weather Bureau stations was one of the principal reasons for undertaking the local studyo Since hourly records of lapse rate between 25 and 100 ft are available for the Lagoona Beach site, it was possible to compute the relative frequency of inversions for each hour of the day and then consider the diurnal variation of inversion frequencyo A somewhat similar analysis, but for 6-hour intervals, was undertaken of the lapse-rate data obtained on the WJBK-TV tower in Detroit, The diurnal variation of inversion frequency at both sites was computed for each season and for the year as a whole, as shown in Tables IV and V, and displayed graphically in Figs. 1-5. The results at WJBK-TV were altogether typical of a continental station with a pronounced nocturnal maximum, An interesting feature at the Lagoona Beach site was a secondary maximum during the afternoon, a maximum as large as the nocturnal one but somewhat shorter in duration. The feature was most pronounced in the summer and least pronounced in the fall, but it was discernible at all seasons. A more detailed analysis of the data showed that there were 13 instances of afternoon inversions in June and 10 in July, 1957. A preliminary scanning of the 100-ft wind records at Lagoona Beach for these 23 days revealed a systematic backing of the wind around to the southeasterly quadrant, i.eo, off the lake during the daytime, followed by a gradual veering again during the evening and night Clearly a lake breeze bringing cool air off the lake was responsible for the inversionso Later sections of this report will present a detailed analysis of the land- and lake-breeze effect at Lagoona Beach as revealed by the meteorological conditions on those 23 summer days in 1957. 74

2, IDENTIFYING THE PHENOMENON Land and lake breezes are localized shoreline wind circulations the essential features of which are onshore winds during the daytime and offshore winds at nighto The onshore wind, designated the lake breeze, is usually better defined than the offshore wind, in turn designated the land breeze, but this difference might be less well marked if it were the custom to compare the lake breeze measured at a shore installation with the land breeze measured some distance off shore. The lake breeze is commonly associated with relief from summer heat because it is accompanied by local cooling along a narrow coastal strip of lando As stated before, it is a local circulation, most evident right at the shoreline where the full effect of wind speed and temperature contrast is felt which fades out rather rapidly a few miles inland. The lake breeze has been studied more than the land breeze because it is simpler to provide a close network of observing stations over land than over watero Further details about the mechanics of land and lake breezes appear in Appendix Bo 30 CHARACTERISTICS OF LAND AND LAKE BREEZES The bulk of observational data on local winds of this type applies to shores of bodies of water larger than Lake Erie, so it would be a mistake to expect an exact replica at the Lagoona Beach siteo Nevertheless, the body of observational data permits a few generalizations which are summarized belowo (1) The phenomenon is most likely to be observed if the general pressure gradient is very weako (2) The phenomenon requires the presence of strong sunlight; hence in northern latitudes it is most likely to occur in the summer. (3) The lake breeze usually starts 2 or 3 hours before noon, is most pronounced about mid-afternoon, and subsides by sunseto (4) In the absence of strong pressure gradients, onset is gradual. Nothing striking occurs at the coast although the temperature usually becomes steady. A pronounced gradient often leads to a delayed onset which occurs as a sort of cold frontal passage, complete with squally winds and temperature drop, (5) The Coriolis effect, although measurable, is not great and is not usually evident until some 5 or 6 hours after the onset of the lake breeze 4, LAKE BREEZE EFFECTS AT LAGOONA BEACH Pressure Gradient During Lake Breeze -Although the use of mean pressure 75

maps is a somewhat unrefined technique, in this case such maps help to throw some light on the situation, Mean sea level pressures were obtained from the U. S. Weather Bureau Daily Weather Map for each of the 23 lake-breeze days for 22 weather stations around the Great Lakes and in neighboring areas. Thus it was possible to construct a mean map representing the average synoptic situation at Lagoona Beach for lake-breeze situations. This mean map is shown in Fig. 23. The first feature that is evident is the weakness of the gradient which is, of course, favorable to the development of the lake-breeze effect. Secondly, it may be noted that the mean gradient is almost perpendicular to the shoreline at Lagoona Beach causing little if any trans-shoreline flow with a gradient wind. Therefore, any occurrences of onshore or offshore winds must be attributed to the land- and lake-breeze effecto Finally, it may be observed that the synoptic situation is one which characteristically leads to high temperatures in the region of the Great Lakes, Thus we may expect not only that the temperature difference over land and lake may become extreme during the afternoon, but also that a temperature inversion may be a semipermanent feature of the meteorological situation over the lake. Windrose Analysis o-Separate windroses were prepared for eight 3-hour periods to display the diurnal shifting of the wind. These are presented in Fig. 24. In the light of the available observational data on penetration of lake breezes, it seems likely that Stoney Point to the south of Lagoona Beach will have relatively little influence on the lake breeze and that for present purposes, the predominant SW-NE shoreline will determine the local circulation. This would require us to include S, SSE, SE, and ESE winds as lake breezeso It is indicated from Fig. 24 that the onset of the lake breeze is rather gradual. Since the windroses represent the integrated effect of 23 days, their interpretation indicates that the onset occasionally takes place before noon, that the lake breeze is most generally realized during the 3 hours ending at 1500 EST, and that on many days it has disappeared by 2100 EST. The characteristic direction appears to be between SE and SSE or nearly at right angles to the general shoreline. Since a backing of the wind precedes the full realization of the lake breeze, it is difficult to detect any Coriolis effect Synoptic Study of Winds and Temperatures.-One of the aspects of the lakebreeze effect at Lagoona Beach which was evident from the beginning of the investigation was the association of the phenomenon with unusually warm weathero This directed attention to the temperatures at Toledo Express Airport as a sort of control station where the modifying effect of the lake breeze would not be felto Mean hourly temperatures for the 23 days were computed for Toledo from the monthly climatological summaries and for Lagoona Beach from the thermograph records. Taking a'somewhat more conservative view of the direction of lake breezes, the frequencies of ESE, SE, and SSE winds were combined into a single class to represent the lake breeze, The frequencies of winds from the opposite sector 76

LL~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~............. i~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~it~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~...... —:-:_-r-:i:::::::,::::_::::_:i::-i:~~~~~~~~~~~~~~~~~~: ~~i.:ijigjijijii~~~~~~~iijl~~~iii~................. 13-j...... XX~_~iii~~-iii'::i~~'~~~-:'i~-.............................~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~_:::i~~::::-i:ii:gl —:::::::_:Il:i~::~::iii:::X~~~~~~~1 ~ ~ ~ fh...... jiiiil ~:':::::-:-::::,i~l~ i~il:::i~i~i::::I:::X R X...............:.I-:::i-::: __ — Ii —-_: -—: v::::::::I::::: i~~~~~~~~ii:~~~~~~~~~'ii-i~'~~~~~~~~~~~~~~~~~-isiiiiiliiii~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~ ~~~~~~~~~:........... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ii;::i.:iifi iiiiji~iQ:i~iiii Franklin: ~ ~ ~ ~ ~ ~ ~ i ~ 8ii(ii.iiri iiiiiiiij iiiiiiiii~i~~ii:iiii~i ~ iiiiii~iiiiiiviiii........................iiiiiiiiiii i'iil~l!Jil~~i'l~~iiii: iiiiii'ii'i~iiiii~iiiiiii ii~iii-iiiiii-i~iiiiiiiXi................*iriijjii i-iliiiii-iii~i-ii:iiilCO Q,::::: ~ ~ ~~~~~~~~~~~::.:.~~~~~~~~~i~~~~~~ijii:~~~~~~~~~~~~~~~~~:~~~~.~~~~~~~~~~~i~~~~~~~~i~~~~i~~~~~~~~~~~i~Liera ~D d~~: t ~ ~ lri~i:"illiiiiiiiiiiiiiiiii'iX..........iiiiiniliiii~i~ii U1 ~~~~~~~~~~~8~I'~':'-"~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~~~~~~~~~I CD i~~~i::i:::::::w::::::::::~~~~~~~~~~~~~~~~~~~~i;: r0 ~ ~ ~ X CO ~~-t3 ~ ~ ~ ~:-i~~~~i:::::::::::j::::::::::::::i:::::::~~~~~~~~~~~~~~~~~~~~mll Y i~~~~~~~~~~~~~~~~~-iiiii~~~~~~~~~~~~~~~~~~~~~~~~~~~~~lii~~~~~~~~~~~~~~~~~io iiii- r~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~...... ~ ~~D il~~~~~~i::iiiliii~~~~~~~~~~~~i~~~iii~:iiiiiii~~~~~~~~~~~~~~~l iriiililil ~ ~ ~ ~ ~ ~ ~ ~ Rxt ~i~~~~~~~~~~~~~~~~~~~~ifi~~~~~~~~~~~~~~~~~~~~~~~~~i'~~~~~~~~~~~~~~~~~~~~lii~~~~~~~~~~~~~~~~~~~~~~~~~iD8~~~~~~~~~........ Q3~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ CD C C+ Q3~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ CD t-t~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~........ O fii~~~~~~~~~l~~~~~~ii~~~~~ii~~~~~i~~~~i~~~~~~~~i~~~~iiff~~~~~~~ ~~~~~ a~~~~~~i............... Y~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~X [V~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~X...... PI CD~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~..... ct-.'iiiiiiiiiiiiiisiii:.:::::::::......... ~~~~~~rliiiiii-i i::::::::::::::::ii:~i~~~~~~~~~~~~~~~~~~~~~~~~~X ~ ~~~D ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ iisiii~~~~~~~~~~~~~~~~~~~~iiiiii;:iii............................................

0100-0300 0400-0600 0700-0900 N N N NW NENWNEN E NW W I57 NE 15% / / /o 15%,15% 10/ / ^'r10 A - 10 SW'E W E W E SS SSS 1000-1200 041300-061500 071600-1800 N N N NW / NE NW \ /NENE 15% 15% 15 E W $E a VWSE 1900- 2100 2200- 2400 Fig. 24. Three hourly windroses for 23 selected lake-breeze days at the Enrico Fermi site. 78

WNWJ, FNW, and NNW were combined for evidence of the nocturnal land breeze. These data and the temperature records discussed above have been plotted in Fig. 25 to permit comparisons. The interval 1200 to 1800 EST is strikingly displayed as the characteristic lake-breeze period. By referring to the bottom block of the figure, it may be seen that during this 6-hour interval the temperature at Monroe remains essentially constant at a temperature of 800F, as we would expect it to do, while that at Toledo rises to a maximum of 86~Fo However, the interval within which the temperature at Monroe is depressed in relation to that at Toledo is somewhat longer, extending from about 1000 EST to 2000 ESTo Combining the two pieces of evidence, one may infer that the average time of development of the lake breeze is about 1000 EST and that virtually 100% of all lake breezes have formed by 1200 ESTo We also may infer that the lake-breeze regime, in some instances, terminates as early as 1800 EST and that half of it has terminated by 2000 ESTo Turning our attention to the land breeze from the middle chart of Fig. 25, the evidence is clear that a land breeze regime is occasionally realized. The frequency of winds from the W, WNW, and NW reaches a maximum during the last hours of darkness. Further, reference to the second windrose of Fig. 24 indicates that these are the prevailing winds for the hours ending 0400, 0500, and 0600o Returning to the mean map of Fig. 23 we see that these winds, blowing from low to high pressure, are in no sense characteristic of the circulation patterno We may conclude that some form of local circulation from land to water has developed on many of the 23 days studied, and tentatively identify this as the nocturnal land breeze. There remain some weaknesses in the evidence. For example, the average lake temperature at the Monroe Waterworks intake for the 23 days was 67.1~Fo We observe that this is cooler, not warmer, than the average minimum observed at Lagoona Beach. On the other hand, the elevation of the temperature at Lagoona Beach that occurs at night in comparison to Toledo may result from the presence of a light circulation. Clearly the land breeze is less in evidence than the lake breeze, which is consistent with theory and with observation elsewhere 5. CONCLUSIONS a. A lake breeze develops at Lagoona Beach on warm summer days when the pressure gradient is light. bo About half of the lake breezes occurred from 1000 EST to 2000 EST and virtually all of them persist from noon to 1800 ESTo co The lake breeze is associated with a temperature inversion but wind speeds are generally 10 mph throughout~ 79

70 60ESE, SE 8 SSE Au 50 - 50._ CL 40>. 3020i. 10 0300 0600 0900 1200 1500 1800 2100 2400 Time in Hours 60 450- W, WNW a NW CL 0) a20 10 v0 0300 0600 0900 1200 1500 1800 2100 2400 Time in Hours Monroe ______ at M e ----— Toledo l — e 80 c0 8. % E \.. a' 4. I, _________I 6060 0300 0600 0900 1200 1500 1800 2100 2400 Time in Hours Fig. 25. Percentage frequency of diurnal lake breeze, ESE, SE, and SSE and diurnal land breeze, W, WNW, and I\W and diurnal temperatures in ~F at Monroe and Toledo for 25 selected lake-breeze days. 80

d. The significance of this association of inversion and lake breeze in relation to diffusion patterns at Lagoona Beach is not entirely obvious since the trajectories of air after crossing the beach are unknown. However, it is clear that inversions associated with moderate winds and a meso-scale mixing process, as these are, offer a better diffusion regime than is customary to associate with inversionso e Under the same meteorological situation, it appears that a nocturnal land breeze often develops. The land breeze is evidently weaker and/or less likely to occur than the lake breezeo 81

IVo ANALYSIS OF PRECIPITATION DATA 1. INTRODUCTION Precipitation is one of the weather elements requiring consideration because of its scavenging effect upon particulates and gases suspended in air. From the standpoint of air pollution, the occurrence of rain may be either desirable or undesirable depending upon whether the scavenging takes place over an unpopulated area or a populated center. We observe that in the vicinity of Lagoona Beach the heavily populated areas are less extensive than the thinly populated areas. If we assume that the areas of rainfall occurrence are randomly distributed, we must concede that rainfall will be desirable more often than undesirable. With these considerations in mind, we observe the frequency of rainfall at Lagoona Beach, comparing its frequency to that at Toledo Express Airport for the same period, and to the frequencies at Toledo Municipal Airport established over a 5-year period for the same season. As a further refinement, the analysis is undertaken separately for each wind direction. Thus we are able to tell at a glance if there is an association of precipitation with wind directiono The manner in which this is done is described in Section 4 of this part, The frequency of measurable precipitation-i,e,,.02 inch at Lagoona Beach and.01 inch at Toledo-and the pertinent wind data are presented season by season along with an annual summary for the above 3 stations in Tables XLVIIILXII. Figures 26 to 30 serve to illustrate graphically the association of winds with precipitation. 2, SEASONAL VARIATIONS IN FREQUENCY OF PRECIPITATION Referring to Tables XLVIII - LXII, the entry at the bottom of the last column indicates the relative frequency of measurable precipitation for the station and season giveno All these entries are summarized into Table LXIII for convenience, Precipitation is, of course, more frequent in winter and Spring than in the other seasons. The 12 months under study are typical in this regard. The indicated deficiency at the Enrico Fermi site can be attributed to the different sensitivities of the two types of rain gages in use. 82

TABLE XLVIII THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE ENRICO FERMI SITE 1 December 1956 - 28 February 1957 (Winter) Average Average Wind No. of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total mph m ph Precipitation Precipitation Hours N 14.2 20o6 9 7.6 0.4 NNE 14.9 17.8 14 11.9 o.6 NE 16.0 22 4 17 14.4 o.8 ENE 12.2 9ol 8 6.8 0,4 E 12.0 7.1 7 5~9 0.3 ESE 11.7 10o8 4 3.4 0.2 SE 111o 11o0 5 4.2 0.2 SSE 12.0 14o0 1 0.8 0.1 S 1353 14.4 5 4.2 0.2 SSW 15.2 15o9 14 11o9 o,6 sw 15o0 8o0 3 2,5 0ol WSW 1305 11o 15 12o7 0.7 W 1351 6.8 6 5.1 003 WNW 12.7 7o3 3 2.5 0ol NW 11 2 12 7 3 2.5 0.l NNW 11.6 18o5 4 3.4 0o2 Calm 0.0 0.0 0 0,0 0,0 Totals 118 100o0 5.3 Average 1353 14.5 85

TABLE XLIX THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO EXPRESS AIRPORT 1 December 1956 - 28 February 1957 (Winter) Average Average Wind No. of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total ___ mph mph Precipitation Precipitation Hours N 10o8 13.3 22 12.5 1.0 NNE 11.0 12,2 20 11o4 0.9 NE 10.0 13ol 14 8,0 o06 ENE 9.0 11.0 9 5.1 0.4 E 9.1 7.6 8 4.5 0.4 ESE 7o5 4.8 3 1.7 Ool SE 6.0 5o7 3 1.7 0.1 SSE 7.4 6o2 5 2.8 0.2 S 10.0 11.3 11 6.3 0.5 SSW 12.6 12.8 21 11o9 1.0 SW 12o9 12,4 18 10.2 o.8 WSW 11o9 9.7 16 901 0o7 W 10o8 9.2 5 2.8 002 WNW 10o4 805 8 4o5 0,4 NW 9.9 6.8 6 3.4 03, NNW 9.5 10.5 5 2.8 0,2 Calm 0.0 0.0 2 1,1 0,1 Totals 176 100.0 7 9 Average 10.4 10,9 84

TABLE L THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO MUNICIPAL AIRPORT 1 January 1950 - 31 December 1954 (Winter Seasons) Average No. of Hours of Precipitation Wind Wind Observations as Percentage of Direction Speed, During Total Hours of Total mph. Precipitation Precipitation Hours N 12.1 78 7.1 0 7 NNE 15,9 81 7,4 0.7 NE 13,6 75 6.8 0,7 ENE 16.7 136 12,4 1,3 E 12,0 73 6.7 0.7 ESE 11.9 46 4.2 0.4 SE 11.1 57 5.2 0.5 SSE 13o9 60 5.5 0.6 S 14,6 116 o106 1,1 SSW 15.2 114 10.4 1,1 SW 16,9 77 7.0 0,7 WSW 15.7 47 4,3 0,4 W 12,4 26 2.4 0,2 WNW 14o5 32 2.9 0.3 NW 14 3 47 4.3 0.4 NNW 1355 29 2.6 0.3 Calm 0.0 2 0.2 0.0 Totals 1096 1000 10.1 Average 14 3 85

N N NW/ \^~'^NE NWN ~ ——'~~ NE / 15% amph 15% a mph W, 02 E W E E S W SE S S S TOLEDO MUNICIPAL AIRPORT TOLEDO EXPRESS AIRPORT TOLEDO, OHIO TOLEDO, OHIO Winter( Dec., Jan., Feb.) 1950-1954 Winter( Dec., Jan., Feb.) 1957 N NE /SW r\ I ^ F S ENRICO FERMI POWER PLANT SITE LAGOONA BEACH, MICHIGAN Winter( Dec., Jan., Feb.) 1957 Fig. 26. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Winter Seasons, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Winter, 1956-1957. 86

TABLE LI THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE ENRICO FERMI SITE 1 March 1957 - 31 May 1957 (Spring) Average Average Wind No. of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total mph mph Precipitation Precipitation Hours N 10,2 5o3 3 1.6 0,1 NNE 14o4 14.3 9 4,7 0.4 NE 15.9 15o3 9 4.7 0.4 ENE 16.5 18,9 36 18.7 1.6 E 13o6 25.5 38 19.7 1.7 ESE 14.2 15.7 8 4.1 0.4 SE 1356 17.1 20 10o4 O.9 SSE 11.1 13.5 12 6o2 0.5 S 10.9 9.7 6 3.1 0.3 SSW 12.4 12.4 8 4.1 0o4 SW 14.7 14.5 10 5o2 0.5 WSW 16.1 14.8 9 4.7 0.4 W 12.8 15o5 2 lo0 0ol WNW 15o0 17o2 20 10.4 009 NW 1359 12.0 3 1.6 0o1 NNW 10o6 0o0 0 0o0 0o0 Calm 0o0 0.0 0 0.0 0.0 Totals 193 100o 807 Average 14.0 17.7 87

TABLE LII THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO EXPRESS AIRPORT 1 March 1957 - 31 May 1957 (Spring) Average Average Wind No. of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total mph mph Precipitation Precipitation Hours N 9.9 12.0 1 0.5 0.1 NNE 11o2 9.0 16 7.9 0.7 NE 10.0 9.5 16 7.9 0.7 ENE 12.2 11.4 50 14.9 1.4 E 12.5 14.2 54 26.7 2.4 ESE 8.6 8.6 6 3.0 0.3 SE 9.0 9.3 4 2.0 0.2 SSE 11.5 12.4 14 6.9 0.6 S 10.9 10.1 14 6.9 0.6 SSW 12.9 14.3 12 5.9 0.5 SW 15.4 12.3 10 5.0 0.5 WSW 16.3 11.5 4 2.0 0.2 W 11.9 10.0 3 1.5 0.1 WNW 11.4 10.6 10 5.0 0.5 NW 11.0 11.5 8 4.0 0.4 NNW 9.7 0.0 0 0.0 0.0 Calm 0.0 0.0 0 0.0 0,0 Totals 202 100.0 9.2 Average 12.1 13.1 88

TABLE LIII THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO MUNICIPAL AIRPORT 1 January 1950 - 31 December 1954 (Spring Seasons) Average No, of Hours of Precipitation Wind Wind Observations as Percentage of Direction Speed, During Total Hours of Total mph Precipitation Precipitation Hours N 13.3 26 207 0.2 NNE 14o0 34 3.5 Oo3.NE 1359 69 7.1 0o6 ENE 1603 193 19,8 1.7 E 1304 98 10.1 0.9 ESE 14o5 44 4o5 0o4 SE 11.6 40 4,1 0o4 SSE 140o 49 5o0 0o4 s 14.6 49 5o0 0.4 SSW 15o4 73 7.5 0.7 Sw 14o8 -84 8.6 oo8 WSW 16o4 46 4.7 004 w 14.3 45 4.6 0o4 WNW 15.5 57 5o9 0.5 NW 1606 40 4.1 0o4 NNW 11.5 23 2o4 0,2 Calm Oo0 4 0.4 0.0 Totals 974 100.0 8.8 Average 14 7 89

N N NW -NE NW,-C^^ >NE /150% mph mph W I~^T0 O L''"*""E W- o 0o 1 SW S E S W E S S TOLEDO MUNICIPAL AIRPORT TOLEDO EXPRESS AIRPORT TOLEDO, OHIO TOLEDO, OHIO Spring ( Mar., Apr., May) 1950-1954 Spring( Mar., Apr., May) 1957 N NW NE 15%a mph W 0 - -' N E S ENRICO FERMI POWER PLANT SITE LAGOONA BEACH, MICHIGAN Spring (Mar., Apr., May) 1957 Fig. 27. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Spring Seasons, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Spring, 1957. 90

TABLE LIV THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE ENRICO FERMI SITE 1 June 1957 - 31 August 1957 (Summer) Average Average Wind No. of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total mph mph Precipitation Precipitation Hours N 8.2 7.0 1 2.2 Ool NNE 9.6 6.7 3 6~7 0.1 NE 14.0 1.0 1 2,2 0.1 ENE 1530 10,0 1 2.2 0ol E 10.5 6,0 3 6.7 0.1 ESE 11,4 5.5 2 4,4 0,1 SE 10,5 0.0 0 Oo0 0,O SSE 9,4 5o5 2 4.4 0.1 S 908 11.8 8 178 04 SSW 10 3 13.5 4 8,9 0,2 SW 10.4 12.0 6 13.3 03, WSW 10.5 10.5 6 13.3 03, W 10o4 7.0 2 4)4 0,1 WNW 10.7 12,0 1 2,2 O01 NW 93. 12.0 1 2,2 0.1 NNW 8.6 11.5 4 8,9 0,2 Calm.0 0.0 0 0.0 0.0 Totals 45 99 8 2.4 Average 10.4 9.9 91

TABLE LV THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO EXPRESS AIRPORT 1 June 1957 - 31 August 1957 (Summer) Average Average Wind No. of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total mph mph Precipitation Precipitation Hours N 7.8 7~8 10 9.2 0~5 NNE 9.1 7.6 5 4.6 0.2 NE 9.1 10o8 4 1.8 0ol ENE 9.9 5.0 2 1.8 0.1 E 7.7 7.0 2 1.8 0,1 ESE 6.4 5.0 2 1.8 0.1 SE 6.0 8,0 4 3.7 0.2 SSE 6.7 8,2 10 11.0 0.5 S 7.6 8.6 21 19.3 1.0 SSW 9.7 10.3 12 11.9 0.6 SW 9.1 12.3 16 13.8 0.7 WSW 9.7 12.3 9 8.3 0.4 w 8.8 10.3 4 3.7 0.2 WNW 10.5 7.4 5 4.6 0.2 NW 9.3 0.0 0 0.0 0.0 NNW 8.8 10.3 3 2.8 0.1 Calm 0.0 0,0 0 0.0 0,0 Totals 109 100.1 5.0 Average 8.6 9.4 92

TABLE LVI THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO MUNICIPAL AIRPORT 1 January 1950 - 31 December 1954 (Summer Seasons) Average No. of Hours of Precipitation Wind Wind Observations as Percentage of Direction Speed, During Total Hours of Total mph Precipitation Precipitation Hours N 11.2 18 3.8 0.2 NNE 11.5 24 5.0 0.2 NE 11.0 42 8o8 0.4 ENE 10.2 25 5.2 0,2 E 11.3 28 5~9 0.3 ESE 7.6 8 1.7 0.1 SE 7.3 18 308 0.2 SSE 8.2 17 3.6 0.2 S 8.2 27 5.7 0.2 SSW 12.4 62 13.0 0.6 SW 10o8 82 17.2 0.7 WSW 11.4 38 8.0 Oo3 W 9.8 21 4.4 0.2 WN[W 12.0 24 5.0 0.2 NW 10.9 13 2.7 0,1 NNW 13.0 21 4.4 0.2 Calm 0.0 9 1.9 0.1 Totals 477 100,0 4 3 Average 10 6 93

W NE W NE 15%a mph 15% a mph E SW "'~~ ~ SE S TOLEDO MUNICIPAL AIRPORT S TOLEDO, OHIO TOLEDO EXPRESS AIRPORT TOLEDO, OHIO Summer ( Jun., Jul., Aug.) 1950-1954 Summer ( Jun., Jul., Aug.) 1957 W I NE 15% a mph SW E S ENRICO FERMI POWER PLANT SITE LAGOONA BEACH, MICHIGAN Summer( Jun., Jul., Aug.) 1957 Fig. 28. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Summer Seasons, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Summer, 1957. 94

TABLE LVII THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE ENRICO FERMI SITE 1 September 1957 - 30 November 1957 (Fall) Average Average Wind No. of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total mph mph - Precipitation Precipitation Hours N 9.8 0.0 0 0.0 0.0 NNE 8,8 0.0 0 0.0 0.0 NE 14.5 1l0 1 1.2 0.1 ENE 13.5 9~5 2 2.4 0,1 E 11.6 13.0 2 2,4 01o ESE 9.7 9.0 1 1.2 0.1 SE 12,5 19.7 7 8.4 0.3 SSE 12.2 14.8 18 21.7 0o9 S 11 15 11 1.5 11 135 0,5 SSW 1355 14.2 16 19.3 0o8 SW 12.7 11.3 8 9.6 0,4 WSW 16.0 12.8 5 6.0 0.2 W 11.6 8.7 3 3.6 0.1 WNW 10.2 12.3 3 3.6 0,1 NW 10,6 7.0 2 2.4 0,1 NNW 10.0 18o5 4 4.8 0.2 Calm 0.0 0,0 0 0.0 0,0 Totals 83 99.9 4 0 Average 12,1 11.8 95

TABLE LVIII THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO EXPRESS AIRPORT 1 September 1957 - 30 November 1957 (Fall) Average Average Wind No. of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total mph mph Precipitation Precipitation Hours N 8.0 17.0 1 0.7 0.0 NNE 8.5 OoO 0 0.0 0oO NE 8.4 7~7 3 2.1 0.1 ENE 9.5 10.0 2 1.4 0.1 E 9.2 8.9 10 7.1 0.5 ESE 6.7 5~0 1 0.7 0.0 SE 7~7 10o5 6 4~3 0.3 SSE 10o4 15.0 21 15.0 1.0 S 906 12.7 36 25.7 1.6 SSW 10.5 14.3 10 7.1 0.5 SW 12 6 11.8 12 8.6 0o5 WSW 12.8 8.9 14 10o0 0.6 W 12.0 13o5 6 4.3 0~3 WNW 9.5 7~5 6 4,3 0o3 NW 8,3 706 5 3.6 0.2 NNW 8o9 12.1 7 5o0 0.3 Calm 0.0 0.0 0 0.0 0,0 Totals 140 9999 6.3 Average 9.9 11o8 96

TABLE LIX THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO MUNICIPAL AIRPORT 1 January 1950 - 31 December 1954 (Fall Seasons) Average No. of Hours of Precipitation Wind Wind Observations as Percentage of Direction Speed, During Total Hours of Total mph Precipitation Precipitation Hours N 14.6 6 5.7 0.3 NNE 15o2 40 6.3 0.4 NE 11.5 27 4.3 0.2 ENE 14.3 35 5.5 0.3 E 10o8 53 8.4 0.5 ESE 10o 15 2.4 0.1 SE 9,4 14 2.2 Ool SSE 13.6 35 5~5 0,3 S 14 3 69 10o9 0.6 SSW 13.6 77 12.1 0,7 SW 12 4 79 12.5 0.7 WSW 12o2 48 7,6 0.4 W 9.7 23 306 0.2 WNW 12.9 27 4.3 002 NW 17.1 33 5.2 0,3 NNW 19,2 18 2.8 002 Calm 0.0 5 0.8 0.0 Totals 634 100.0 5.8 Average 13.2 97

NW WNE NW^ ^' yNE " 15% mph 15% mp I0 m 0 W E 8 E W 0 0 E sw SE sw SE s TOLEDO MUNICIPAL AIRPORT TOLEDO, OHIO TOLEDO EXPRESS AIRPORT Fall ( Sept., Oct., Nov.) 1950-1954 TOLEDO, OHIO N Fall ( Sept., Oct., Nov.) 1957 15% a mph W!- ( O.0 - E S W SE ENRICO FERMI POWER PLANT SITE LAGOONA BEACH, MICHIGAN Fall( Sept., Oct., Nov.) 1957 Fig. 29. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Fall Seasons, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Fall, 1957. 98

TABLE LX THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE ENRICO FERMI SITE 1 December 1956 - 30 November 1957 (Annual Summary) Average Average Wind No. of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total mph mph Precipitation Precipitation Hours N 10.9 16.2 13 350 0.2 NNE 12.1 15.3 26 5.9 0.3 NE 15.2 18.6 28 6.4 0.3 ENE 14o6 16.7 47 10o8 o06 E 13.7 21.6 49 11.2 0.6 ESE 11.8 12.3 16 3.7 0.2 SE 11.9 16.7 32 7~3 0.4 SSE 10.8 1359 32 7.3 0o4 S 11.1 12,4 30 6.9 0.4 SSW 12,8 14.4 42 9.6 0.5 SW 13.3 12.3 27 6.2 0.3 WSW 1359 12.5 32 7.3 0.4 W 12o2 8.0 14 3.2 0,2 WNW 12.4 14,1 28 6o4 0,3 NW 11.1 11.1 9 2,1 0.1 NNW 10.1 16.2 12 2.7 O.1 Calm 0. 0.0 0 0. 0 0.0 Total 437 100.0 5~3 Average 12.5 14 5 99

TABLE LXI THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO EXPRESS AIRPORT 1 December 1956 - 30 November 1957 (Annual Summary) Average Average Wind No of Hours of Precipitation Wind Wind Speed During Observations as Percentage of Direction Speed, Precipitation, During Total Hours of Total mph mph Precipitation Precipitation Hours N 9.6 11.8 35 5o6 0.4 NNE 10.2 10.5 41 6.6 0o5 NE 9~7 10.7 35 5.6 0.4 ENE 110o 11.0 45 7.2 0,5 E 10.9 12.4 72 11.5 o.8 ESE 8,1 6.4 12 1.9 0.1 SE 7.7 8,8 17 2.7 0.2 SSE 9.9 12.0 50 8.0 o06 S 10.3 11.0 84 1354 1.0 SSW 12.0 12.9 55 8.8 O.6 SW 13.3 12,2 55 8o8 o06 WSW 13l1 10,2 40 6.4 0.5 11.8 11.0 18 2.9 0.2 WNW 10o9 8,8 29 4.6 0.3 NW 907 8.5 19 350 0.2 NNW 9.5 11.4 16 2.6 0.2 Calm 0.0 0.0 2 0.3 0.0 Totals 625 99.9 7.1 Average 10o9 11.1 100

TABLE LXII THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO MUNICIPAL AIRPORT 1 January 1950 - 31 December 1954 (Annual Summary) Average No. of Hours of Precipitation Wind Wind Observations as Percentage of Direction Speed, During Total Hours of Total mph Precipitation Precipitation Hours N 12.7 158 5.0 0.4 NNE 14.8 179 5.6 0.4 NE 13o0 213 6.7 0.5 ENE 15.9 389 12.2 0.9 E 12o2 252 7.9 0o6 ESE 12.3 113 3.6 0.3 SE 10.6 129 4.1 0,3 SSE 13.2 161 5.1 0,4 S 13.8 261 8.2 0.6 SSW 14.3 326 10.2 0.7 SW 13.7 322 10.1 0.7 WSW 14.0 179 5.6 0.4 w 12,1 115 3.6 0,3 WNW 14.1 140 4,4 0.3 NW 15. 1133 4.2 0.3 NNW 14.0 91 2.9 0,2 Calm 0.0 20 0.6 0.0 Total 3181 100.0 7.3 Average 13.7 101

N N Ni 15%a mph /N 15%a mph W E W 0" E SWIN SN E S S TOLEDO MUNICIPAL AIRPORT TOLEDO EXPRESS AIRPORT TOLEDO, OHIO TOLEDO, OHIO Annual Summary 1950-1954 Annual Summary 1957 N 15% E mph W E SW..SE S ENRICO FERMI POWER PLANT SITE LAGOONA BEACH, MICHIGAN Annual Summary 1957 Fig. 50. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed with precipitation at Toledo Municipal Airport, Five-Year Summary, 1950-1954, and at Toledo Express Airport and the Enrico Fermi site, Annual Summary, 1956-1957. 102

TABLE LXIII A COMPARISON OF RELATIVE FREQUENCY OF MEASURABLE PRECIPITATION AT THE ENRICO FERMI SITE, TOLEDO EXPRESS AIRPORT, 1 DECEMBER 1956 - 30 NOVEMBER 1957, AND TOLEDO MUNICIPAL AIRPORT, 1 JANUARY 1950 - 51 DECEMBER 1954 (o02 INo MEASURABLE AT PLANT SITE, o01 INo MEASURABLE AT TOLEDO) Enrico Fermi Toledo Express Toledo Municipal Site, %..Airport, % Airport, % Winter 5o3 7o9 10 o Spring 8,7 9~2 808 Summer 2,4 5o0 403 Fall 4o0 6o3 5o8 Annual 5 3 7.1 7 3 30 THE ASSOCIATION OF WIND SPEED WITH PRECIPITATION In general, precipitation is associated with above average wind speeds, This is shown by the overall average wind speed, and the average during precipitation,which appear as the entries at the bottom of columns 1 and 2 of Tables XLVIII - LXIIo However, during the summer and fall, when precipitation is rather infrequent, there is essentially no difference between the overall average wind speed and the average for periods of precipitation only. 4. THE ASSOCIATION OF WIND DIRECTION WITH PRECIPITATION The notion of conditional frequency is helpful in discussing the association of wind direction with precipitation. For example, we may consider the frequency of the event, Heads, in tossing a coin. Let us indicate this by F(H). Let us also consider the conditional frequency of the event, Heads, given that it is raining outsideo The notation is F(H!R)o For an unbiased coin F(H) = F(HIR) = 005 (approximately) because the occurrence of heads when flipping a coin is in no way influenced by raino Now we may consider the analogous situation of conditional frequencies of the event, winds from direction D, given that it is raining [the notation is F(DJR)] and the simple frequency of the event, wind from direction D[notation F(D)]o If the occurrence of winds from direction D is independent of the condition of rain, we should observe that F(DIR) = F(D)o 103

Further, if the occurrence of precipitation and the wind direction are completely independent, then this relationship must hold for all wind directions. The entries of Tables XLVIII-LXII provide us with the values of F(DIR), i.eo, the conditional frequencies, which may be compared to the simple frequencies F(D) from Tables XVIII-XLIIo We conclude that in each season the occurrence of precipitation is in fact dependent upon wind direction since the quantities are generally not approximately equal. Certain other features about the nature of precipitation are also revealedo During the winter, it may be noted that precipitation is associated about equally with northeasterly and southwesterly winds. These may be characterized as pre-warm-frontal and pre-cold-frontal, respectively. The emphasis definitely shifts to the warm-frontal or pre-warm-frontal type of precipitation associated with the easterly winds during the spring. This is seen most easily in the windroses of Fig. 27. During the summer, pre-cold-frontal rain is the dominant type as witnessed by the association of rain with southwesterly winds. Once again this is well illustrated by the windroses in Fig. 28. The picture in the fall does not differ significantly from that in summero 104

Vo CONCLUSIONS Throughout this report, conclusions have been inserted after each parto The following list summarizes the facts presented in the reporto lo Inversion conditions are more frequent at thw WJBK-TV tower than at the Enrico Fermi siteo 2o Three distinct types of inversions occur at the Enrico Fermi site, namely, nocturnal, circulation, and lake-breeze typeso 5. The circulation and lake-breeze type of inversionswhich represent more than half of all the inversions are associated with wind speeds greater than or equal to 10 mph. 4, Inversions associated with moderate winds and a meso-mixing process offer a better diffusion regime than is customary to associate with inversionso 5. Circulation inversions at the plant site may persist for over two days or as long as air which is relatively much warmer than the underlying water crosses Lake Erie from the southo Such inversions are most probable in the late spring and least probable in the fall. 60 The year 1957 appears to be a typical year as concerns wind frequency distributions except for the summer season. 7. The frequency distributions of the wind indicate that Toledo Express Airport gives a closer approximation to the actual distribution at the Enrico Fermi site than does Detroit City Airporto 80 Winds which are off the lake are relatively stronger at the plant site than the same winds at Detroit and Toledoo 9 A lake breeze develops at Lagoona Beach on warm summer days when the pressure gradient is light. Under the same meteorological situation a nocturnal land breeze often develops which is weaker than the lake breeze. 10o Precipitation is generally associated with above average wind speeds at the Enrico Fermi site except during the summer and fall when precipitation is infrequent, and there is no difference between the overall average wind speed and the average wind speed during precipitation. 11. The frequency distribution of precipitation is dependent upon wind direction in all seasons of the yearo 105

APPENDIX A A METHOD FOR ELIMINATING THE BIAS FROM WIND-DIRECTION FREQUENCY STATISTICS lo INTRODUCTION Although it is now standard procedure at first-order weather stations to report wind directions to 16 points of the compass, it is not uncommon to discover evidence of a bias in the records. This bias takes the form of an apparently greater frequency of winds from the eight primary points (N, NE, E, SE, S, SW, W, and NW) than of winds from the eight intermediate points (NNE, ENE, ESE, SSE, SSW, WSW, WNW, and NNW). For example, the record may indicate that N winds are more frequent than NNW or NNE, NE winds are more frequent than NNE or ENE, E winds are more frequent than ENE or ESE, and so on around the compass. Since nature clearly has no preference for the cardinal points unless there is an unusual arrangement of valleys intersecting precisely at the weather station, this improbable result must be attributed to observer bias, specifically a preference for reporting the wind direction as one of the eight primary pointso 2o TESTING FOR PRESENCE OF BIAS In the case of the City A records, there is scarcely any need for a rigorous check for bias since a casual observation shows that a bias existso However, such a check can easily be made by measuring the compatibility of the observed and expected frequencies. This test, known as the Chi-Square Test, is usually designated by X2e k 2 x2 = z (oi-Ei) i=l Ei where 0i = observed frequencies, Ei = expected frequencies, and K = number of pairs of frequencies to be compared. This test should be made when the evidence of bias is not so strikingly evident. Consider the eight cardinal compass directionso The reported frequency of each of these directions may be assigned to one of three categories as follows: 107

Probability Expected Category Identification of Occurrence Occurrences I Reported frequency exceeds that.25 2 of both adjacent intermediate compass points. II Reported frequency exceeds that.50 4 of one adjacent intermediate compass point. III Reported frequency exceeds nei- o25 2 ther adjacent intermediate compass point. The right-hand column indicates the expected frequency of occurrence of this event among eight cardinal compass points. These occurrences are assumed to stem from a population of unbiased recordso The quantity k (Oi-Ei)2 i=l Ei that we are interested in has a X2 distribution with 2 degrees of freedom. This means that a number may be placed in either category I, II, or III but if a value is assigned to any two of these categories, then the value of the third one is fixed since the total of categories I, II, and III must equal 8. The number of degrees of freedom is defined as k-l where k is again the number of pairs of frequencies to be compared. In the case at hand there are three categories so k = 53 Then k-l = 2. Wind-frequency statistics for City A were subjected to a X2 analysis. The results are shown in Table LXIVo TABLE LXIV COMPUTATIONS OF X2 FROM CITY A RECORDS Number of Occurrences Season........ X2 Category I Category II Category III Fall'56 7 0 1 17.00 Winter v56-'57 8 0 0 24.00 Spring'57 6 1 1 10.75 Fall'51-'55 8 0 0 24.00 Winter'51-'55 7 1 0 16.75 Spring'51-'55 7 1 0 16.75 108

From tables of X2 a value greater than 10.60 can be expected to occur with a frequency of less than one in two hundred where there is no bias. The large values of X2 in the above table indicate that it is highly probable that the record has a bias. 3. REMOVING THE BIAS FROM THE RECORD A satisfactory method of removing the bias from the wind record must itself be free of bias, and must involve the minimum amount of smoothing. In the light of these criteria, two tests may be applied to determine the best method of eliminating the bias. First, when a method for removing the bias is applied to a record that is believed to be biased, the resulting table of wind frequencies must indicate no bias when subjected to the X2 test. If two or more methods of removing the bias meet the test of being free of bias, the best method is that which effects the least smoothing to a nonbiased record. Two simple methods of removing the bias will be described, and the best method will be selected on the basis of the two tests stated above. First Method. -The method will be demonstrated with the reported wind occurrences at City A for October and November, 1956. The logic behind the method is as follows. Reported occurrences for each of the cardinal points are considered to be too high (positive bias), whereas for each adjacent intermediate point, occurrences are too low (negative bias). If the average frequency of each compass point and the adjacent clockwise point is computed, an unbiased 16-point wind record is obtained. However, the computed frequencies will refer to 16 points which are rotated 12.25~ clockwise from the desired pointo If frequencies are computed for 16 points which are rotated 12.25~ counterclockwise from the desired directions, by the same procedure, then the average of the two sets of frequencies will be an unbiased record for the desired 16 compass points. As an illustration, consider the case of NE winds (Table LXV)o The reported frequencies of NNE, NE, and ENE winds are 57, 115, and 44, respectively. The average frequency of the NE with the ENE wind is (115+44)/2; the average frequency of the NE with the NNE wind is (115+57)/2. This gives the clockwise and counterclockwise displacement of 12.25~. To get the frequency of the NE winds with the bias removed, we average these two displacements. Therefore the average frequency of NE winds is (115+44)/2 + (115+57)/2 o115 + 44/2 + 57/2 165 82 2 2 2 This then gives us a general equation to compute the frequencies with the bias eliminated: = _ fo + fc/2 + fcc/2 n -2 109

TABLE LXV REPORTED WIND OCCURRENCES AND COMPUTED OCCURRENCES WITH BIAS REMOVED (METHOD 1) City A 1 October 1956 - 30 November 1956 Column Frequency with Wind 1. 2 3 Bias Removed Direction Reported fcc fc 1+2+3 1+2+3 Occurrences 22 2 N 136 16 28 180 90 NNE 57 68 58 183 92 NE 115 28 22 165 82 ENE 44 58 27 129 64 E 54 22 10 86 43 ESE 19 27 96 142 71 SE 191 10 57 258 129 SSE 114 96 66 276 138 S 133 57 33 223 112 SSW 66 66 50 182 91 SW 101 33 34 168 84 WSW 69 50 30 149 74 W 60 34 42 136 68 WNW 83 30 72 185 92 NW 143 42 16 201 100 NNW 32 72 68 172 86 Calm 47.-> — 47 110

where fn = new computed frequency with the bias eliminated, fo = old frequency at the point under consideration, fc= old frequency next to the point under consideration in the clockwise direction, and fcc = old frequency next to the point under consideration in a counterclockwise direction. The computed frequencies with bias eliminated appear as the last column of Table LXV. In Table LXIV it was pointed out that the original record yielded a value of X2 of 17o00. The new record gives X2 = 0.75, indicating the effect of the smoothing processo In this case we assume, therefore, that most of the bias has been eliminated. Second Method -The second method assumes that the positive bias of the cardinal points is constant and that valid comparisons between cardinal points are offered by the reported frequencieso Similarly, it assumes that the negative bias of the intermediate points is constant and that valid comparisons may be made between intermediate points. That is to say, if the reported frequency of NE winds is twice that of E winds, this may be accepted as their true relationship although both are actually less frequent than reported, The computations, which are illustrated in Table LXVI, first effect a transformation into an unbiased 8-point record by apportioning the occurrences of the intermediate points to the adjacent cardinal points on the basis of the comparative frequencies of the two cardinal points. Having done this, half of the computed 8-point occurrences are attributed to the central 22.5~ of the whole 450 sector. The remaining half of the 8-point occurrences are apportioned between the adjacent intermediate points on the basis of their comparative occurrences. The occurrences of the cardinal points with the bias removed are obtained by halving the 8-point occurrenceso As an illustration, consider the reported frequencies of N, NNE, NE, ENE, and E winds which are 136, 57, 115, 44, and 54, respectively (Table LXV) Computing the occurrence of NE winds with the bias removed for an 8-point compass we get 115 + ( 11 7 + (115 = 115 + 26 + 30 = 171 k115+156/ ^115+54 By halving this number, the occurrence of NE winds with bias eliminated is obtained (171/2 = 86). The remaining 85 occurrences (171-86) are assigned to NNE and ENE as follows: to NNE, [57/(57+44)]85 = 48, and to ENE, (85-48 = 37). Thus each of the newly computed frequencies for the intermediate direction will have two components. The right-hand column in Table LXVI gives X2 = 2.00, which falls within our assumed criterion for the elimination of the biaso 111

TABLE LXVI REPORTED WIND OCCURRENCES AND COMPUTED OCCURRENCES WITH BIAS REMOVED (METHOD 2) City A 1 October 1956 - 30 November 1956 Wind. Reported Add to 8-Point Components of 16-Point Direction Occurrences ardinal Bias Intermediate Occurrence s Direct ion Occurrences Points Removed Points Bias Removed N 136 15+31 182 91 NNE 57 58+48 106 NE 115 26+30 171 86 ENE 44 37+25 62 E 54 14+4 72 36 ESE 19 11+20 31 SE 191 15+67 273 136 SSE 114 117+69 186 S 133 47+38 218 109 SSW 66 40+42 82 SW 101 28+43 172 86 WSW 69 44+25 69 W 60 26+25 111 56 WNW 83 30+79 109 NW 143 58+17 218 109 NNW 32 33+30 63 Calm 47.> 47 112

4. COMPARISON OF METHOD 1 AND METHOD 2 The two methods may be compared by applying each of them to the reported occurrences at City B for the period 12 October - 30 November 1956. Table LXVII contains reported occurrences at City B, and computed occurrences with the bias eliminated by use of both methods. Since the reported occurrences gives X2 = 2.75, the record appears to be unbiased. Accordingly, the better method will be that which effects the least smoothing to the frequencies as reported. Figure 31 presents graphically this comparison between reported relative frequencies and relative frequencies computed by the two methods for removal of bias. Method 1 has a standard deviation of 2. 4% from the reported relative frequencies, compared to 1.6% for method 2o Method 2 is therefore selected as the better of the two. 5. CONCLUSION By means of a simple Chi-square test, bias may be detected in records of occurrences of winds by directions. Biased records may have the bias removed with a minimum of smoothing by the second of the two methods described in the foregoing. In the present report, all tables of wind occurrences for City A have had the bias removed in this wayo Records with the bias eliminated are better than biased records, but can never be more than an approach to the true, unbiased recordo Observers should be trained to observe winds without making the observations subject to personal preferences. 113

TABLE LXVII FREQUENCY OF OCCURRENCE OF WINDS FROM VARIOUS DIRECTIONS AS REPORTED AND AS COMPUTED BY TWO METHODS FOR REMOVING THE BIAS City B 12 October 1956 - 30 November 1956 Wind Occurrences Relative Frequencies Direction Reported Method 1 Method 2 Reported Method 1 Method 2 N 103 106 130 8.7 8.9 11.0 NNE 195 132 162 16.5 11 1 13 7 NE 37 70 48 351 5.9 4.1 ENE 9 15 6 0.8 1.3 0.5 E 6 9 4 0.5 0.8 0.3 ESE 17 19 16 1.4 1.6 1.3 SE 35 32 30 3.0 2.7 2.5 SSE 40 55 41 3.4 4.6 3.5 S 105 113 136 8.8 9.5 11.5 SSW 202 139 164 17.0 11.7 13.8 SW 49 92 75 4,1 7.8 6.3 WSW 67 54 48 5.7 4.6 4.1 W 37 54 49 3.1 4.6 4.1 WNW 77 60 68 6.5 5.1 5.7 NW 52 51 52 44 44 4 4.4 NNW 23 50 22 1.9 4.2 1.9 Calm 131 131 131 11.1 11.1 11.1 114

18 ----- 1 _ _ x --- x REPORTED ____ 16 --—. METHOD I 14 o-.-.-.0o METHOD 2 ___ z A 12 ____ 0* cr H X~W LL ^V \ >~~~~~ _I /1' < 4 ___ ____ ______ ___ __ I 2 ___^^_ ____ _ __! N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW WIND DIRECTION Fig. 51. Comparison of relative frequencies of wind at City B, USA, as reported and as computed by the two methods for removing bias, 12 October - 50 November 1956.

APPENDIX B THE FORCE WHICH GENERATES LAND AND LAKE BREEZES It is known that the force which sets the lake breeze in motion is the more rapid heating of the air over land than o- er the adjacent lake surface during the daytime. Conversely, the force which sets the land breeze in motion is the greater cooling of the air over land than over the lake surface at night. Many reasons for the more rapid heating of the land surface than the adjacent water surface have been given. Although the ratio of the specific heats of sand, rock, and typical soil to that of water is about 1 to 5.5, the ratio of their specific gravities is about 307 to 1. The net result is that the ratio of the thermal capacities per unit volume of sand and soil to that of water is about 1 to 1.5. However, the much greater thermal conductivity of the soil and sand compared to the water neutralizes the residual difference from the first two factors and, as pointed out by Defant, "measurements reveal that the surfaces of water and sandy or rocky ground have temperature variations of comparable order." Clearly, then, we must look elsewhere for an explanation of the differential heating that is observed. Wexler6 lists a number of factors that have been suggested at various times as accounting for the phenomenon, showing that each of these must be insignificant. For example it has been suggested that the greater penetration of the sun's rays into the water can account for the differential heating, but it is known that the infrared radiation is absorbed in the uppermost layer of the water. The greater amount of reflected radiation from the water surface has been cited, but Wexler points out that "with the sun at an altitude of 40 degrees the reflection from the water surface is slight (about 4 per cent) as compared to sand" Cooling of the water surface due to evaporation has also been mentioned in this connection, but Wexler reminds us that, with light wind speeds, which is the most favorable situation for sea breeze development, this factor is small. The true explanation for the greater heating of the land surface is found in the turbulent mixing of the water which is set in motion by the waves. This results in a continuous downward flux of the heat which has been introduced at the surface by the sun's rays. Naturally, the temperature variation that takes place at the surface of the water is relatively small. In contrast to this behavior is the complete absorption of the incoming radiant energy on the surface of the sand, rock, or soil. The evidence of this is provided by the extremely high temperatures assumed by such surfaces in the direct summer sun. The manner in which this differential heating generates the lake breeze is s116

described by Brunt.7 Starting with uniform pressure and temperature along the shoreline, the sun warms the air over the land more rapidly than that over the water. Through a layer of a few hundred feet the air becomes less dense over land than over water. Therefore pressure decreases less rapidly with height over land than over water, and at the top of the affected layer, pressure is high over land and low over the water. At this stage in the development of the lake breeze, the orientation of isobaric surfaces and isosteric (equal density) surfaces is as shown in the cross-sectional view of Fig. 32. Brunt shows mathematically that, whenever the isobaric and isosteric surfaces intersect as in Fig. 32, a circulation will be set up tending to bring'the surfaces into phase again. Intuitively, it can be seen from Fig. 32 that air aloft will begin to move out over the water toward the region of lower pressure, inducing pressure changes at the surfaces. As a result of the surface-pressure changes, i.e., decreased over the land and increased over the lake, the surface lake breeze begins to blow. The circulation is closed by broad regions of ascending air over land and descending air over water. The explanation of the land breeze proceeds in quite similar fashion. During the night the cooling of the water surface takes place much less rapidly than the land surface, again because of the turbulent mixing of the water. A local pressure gradient is established, this time in the reverse direction. In fact, the principal difference between the two circulations is introduced by stability factors. In many cases the daytime lake breeze receives an additional acceleration from gravitational forces realized by the establishment of superadiabatic lapse rates over the land. In general, there is no nocturnal counterpart, which accounts to some extent for the greater strength of the lake breeze than the land breeze. H _ L \sossR - rso^ WARM SEA^ C 0 0 L LAND BREEZE /^ 7^ JWATER / /, 7-/ / / /Fig. 32. Schematic diagram of lake-breeze circulation, 117

REFERENCES 1. Baynton, H. W., The Climatology of Low Level Inversion at Mount Clemens, Michigan, and Toledo, Ohio, Internal Report, Can. Sect. Tech. Advis. Bd. on Air Poll., IJC, unpublished paper, 1952. 2. Relations Between Pollution Levels and Meteorological Factors, Chap. 7 in Final Report, IJC, 1958. 3. Hewson, E. W., and Baynton, H. W., Air Pollution Climatology near Monroe, Michigan, Univ. of Mich. Eng. Res. Inst. Report 2442-1-F, 1956. 4. U. S. Atomic Energy Commission, A Meteorological Survey of the Oak Ridge Area, Final Report ORO-99, Technical Information Service, Oak Ridge, Tenn., p. 70. 5. Defant, F., "Local Winds," Compendium of Meteorology, T. F. Malone, Edo (AMS, Boston, 1951), pp. 655-672. 6. Wexler, R., "Theory of Observations of Land and Sea Breezes," Bull. AMS, 27, 272-287 (1946). 7. Brunt, D., Physical and Dynamical Meteorology (Cambridge Univ. Press, New York, 1959), p. 181. 118