ENGINEERING RESEARCH INSTITUTE THE UNIVERSITY OF MICHIGAN ANN ARBOR Second Progress Report METEOROLOGICAL ANALYSIS Eo We. Hewson Profes;sor of Meteorology G. C, Gill Associate Research Engineer J. J. B. Worth Assistant in Research ERI Project 2515 POWER REACTOR DEVELOPMENT COMPANY DETROIT, MICHIGAN March 1958

ACKNOWLEDGMENTS The authors gratefully acknowledge the original contributions made by Eugene W. Bierly and Harold W. Baynton in analysis of the data for this report. ii

TABLE OF CONTENTS Page LIST OF TABLES iv LIST OF FIGURES vi ABSTRACT vii INTRODUCTION 1 ANALYSIS OF WIND DATA 2 1o Winter Season 2 2o Spring Season 16 ANALYSIS OF TEMPERATURE-LAPSE-RATE DATA 18 1. Classification of Lapse-Rate Data 18 2. Inversion Conditions 18 35 Association of Lapse Rates with Wind Directions 24 ANALYSIS OF PRECIPITATION DATA 24 1i Winter Season 59 2. Spring Season 39 CONCLUSIONS 40 iii

LIST OF TABLES No. Page I Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Enrico Fermi Power Plant Site, 1 December 1956 - 28 February 1957 (Winter). 4 II Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Detroit City Airport, 1 December 1956 - 28 February 1957 (Winter)O 5 III Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Toledo Express Airport, 1 December 1956 - 28 February 1957 (Winter) 6 IV Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Toledo Municipal Airport, 1 January 1950 - 31 December 1954 (Winter Season). 7 V Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Enrico Fermi Power Plant Site, 1 March 1957 - 31 May 1957 (Spring). 8 VI Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Detroit City Airport, I March 195731 May 1957 (Spring)o 9 VII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Toledo Express Airport, 1 March 1957 - 31 May 1957 (Spring)o 10 VIII Percentage Frequency of Occurrence of Winds in Various Directions Grouped According to Wind Speeds, Toledo Municipal Airport, 1 January 1950 ~ 31 December 1954 (Spring Season). 11 IX Summary of Temperature-Lapse-Rate Data at the Enrico Fermi Site, 1 December 1.956 - 28 February 1957, and 1 March 1957 - 31 May 1957. 19 X Summary of Temperature-Lapse-Rate Data (Inversions) at the WJBKTV Tower, Detroit, Michigan, 1 December 1956 - 28 February 1957, and 1 March 1957 - 31 May 1957. 19 XI: Frequency of Continuous Inversions at the En.rico Fermi Power Plant Site, 1 December 1956 - 28 February 1957 (Winter). 20 iv

LIST OF TABLES (concluded) No. Page XII Frequency of Continuous Inversions at the WJBK-TV Tower, Detroit, 1 December 1956 - 28 February 1957 (Winter). 21 XIII Frequency of Continuous Inversions at the Enrico Fermi Power Plant Site, 1 March 1957 - 31 May 1957 (Spring). 22 XIV Frequency of Continuous Inversions at the WJBK-TV Tower, Detroit, 1 March 1957 - 31 May 1957 (Spring)o 23 XV The Association of Temperature Lapse Rates with Wind Direction at the Enrico Fermi Power Plant Site, 1 December 1956 28 February 1957 (Winter). 25 XVI The Association of Temperature Lapse Rates with Wind Direction at the Enrico Fermi Power Plant Site, 1 March 1957 - 31 May 1957 (Spring). 26 XVII Mean Wind Speeds Associated with Inversion and Noninversions at the Enrico Fermi Power Plant Site, 1 December 1956 - 28 February 1957 (Winter).27 XVIII Mean Wind Speeds Associated with Inversion and Noninversions at the Enrico Fermi Power Plant Site, 1 March 1957 1 May 1957 (Spring). 28 XIX The Association of Precipitation with Wind at the Enrico Fermi Power Plant Site, 1 December 1956 - 28 February 1957 (Winter)o 51 XX The Association of Precipitation with Wind at Toledo Express Airport, 1 December 1956 - 28 February 1957 (Winter). 52 XXI The Association of Precipitation with Wind at Toledo Municipal Airport, 1 January 1950 - 51 December 1954 (Winter Season). 55 XXII The Association of Precipitation with Wnd at the Enrico Fermi Power Plant Site, 1 March 1957 51 May 1957 (Spring). 34 XXIII The Association of Precipitation with Wind at Toledo Express Airport, 1 March 1957 - 31 May 1957 (Spring). 35 XXIV The Association of Precipitation with Wind at Toledo Municipal Airport, 1 January 1950 - 51 December 1954 (Spring Season). 36 v

LIST OF FIGURES No Page 1. Topographic map of site and surroundings. 3 2. Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Municipal and Express Airports at Toledo, Ohio, Detroit City Airport and Enrico Fermi Power Plant, Winter. 13 35 Percentage frequency of occurrence of winds from 16 directions and corresponding wind speed in mph at Municipal and Express Airports of Toledo, Ohio, Detroit City Airport and Enrico Fermi Power Plant, Spring. 14 4, Mean wind speed at Enrico Fermi Power Plant site and Detroit-Toledo combined, for various directions, expressed as a percentage of the overall mean winter wind speed. 15 5. Mean wind speed at Enrico Fermi Power Plant site and Detroit-Toledo combined, for various directions, expressed as a percentage of the overall mean spring wind speed. 17 6. Percentage frequency of occurrence of winds associated with inversions and noninversions from 16 directions and corresponding wind speeds in mph at Enrico Fermi Power Plant site, Winter (December 1, 1956 - February 28, 1957). 29 7o Percentage frequency of occurrence of winds associated with inversions and noninversions from 16 directions and corresponding wind speeds in mph at Enrico Fermi Power Plant site, Spring (March 1, 1957 - May 31, 1957)- 50 80 Percentage of total winds associated with precipitation from each direction at Enrico Fermi Power Plant site, Toledo Express Airport, and Toledo Municipal Airport, Winter. 37 9, Percentage of total winds associated with precipitation from each direction at Enrico Fermi Power Plant site, Toledo Express Airport, and Toledo Municipal Airport, Spring. 38 vi

ABSTRACT This report contains an analysis of the data accumulated at the Enrico Ferixn Power Plant site during the past winter (December, 1956 - January, February, 1957) and spring (March, April, May, 1957). The instrumentation providing these data remains the same as that described in detail in the first progress report. It consists of a 100-ft steel tower near the lake shore with the following installations: three Bendix-Friez Aerovanes for windmeasurements, and four differential thermocouples, shielded and artificially ventilated, for temperaturelapse-rate measurement s A recording rain gage is also in operation. In this report comparisons'are made between the winds at the plant site, at Detroit City Airport, and at Toledo Express Airport for the same seasons, and with data for the same months for the period 1950-1954 at the Toledo Municipal Airport. Temperature-lapse-rate measurements for the winter and spring seasons are also availableO These are analyzed to show relative frequency of strong lapse rate, weak lapse rate, and inversions, and the relationship between lapse rate, wind direction, and wind speed. Inversion frequencies are compared with those on the WJBK-TV tower in Detroit for part of the same period. The relationship between occurrences of measurable precipitation (o02 ino at Monroe,.01 in. at Toledo and Detroit), and wind direction during the past winter and spring is also reported on. The existing program of weather observation and analysis at the Enrico Fermi Power Plant site is continuing, and plans are being made to conduct special diffusion studies over the lake in the summer of 1958. vii

INTRODUCTION The present study is being undertaken to determine the nature and magnitude of special lake influences on the air-pollution climatology of the Monroe plant site. The special influences which may be uncovered will be either mechanical or thermal in origin: mechanical if they owe their existence to the unusual uniformity of the lake surface compared to a land surface or thermal if they owe their existence to the relative warmth of the lake surface during the cold months of the year, and to its relative coolness during the warm months. Preliminary observations of wind directional traces have shown quite clearly that the smoothness of the lake surface leads to an intensity of mechanical turbulence which is very much less than that over ordinary land surfaces at the same wind speed. For example, it has been observed,.as the wind shifts from SE, off the lake, to SSE across a point of land, that the range of variability of wind direction may be doubled or trebledo This aspect of the study has not yet been subjected to a formal analysiso In the present report, the technique of analysis is to compare the observations at the Enrico Fermi Power Plant site with those at Toledo and Detroit, where special lake influences are absent. Observed differences are believed to be mainly due to thermal. influences, which operate the following wayo During the three winter months Lake Erie acts predomina:tly as a heat sourceo That is to say, most air masses will be warmed at the surface'by passage over the lake although the reverse will be true for unusually warm spells such as that of 4, 5, and 6 December 1956. During March, the mean. heat effect of the lake is neutral, varying from day to dayo Through the remaining spring months, April and May, Lake Erie acts predominantly as a cold source, which means that most air masses will be cooled at the surface by passage over the lakeo In, the individual situation, whenever the lake is cold in relation to the air (cold source), a surface inversion will form over the water, whereas, whenever the lake is warm in relation to the air (heat source), a strong lapse rate will develop over the water. Actually either influence is possible at any season of the yearo Strong lapse rates will increase surface wind speed and turbulence and hence promote rapid diffusion. Inversions will decrease surface wind speed and turbulence and hence inhibit diffusion. The ability of rainfall to scavenge particulate matter from the air is also important. This aspect of air pollution was discussed in the earlier evaluation of the air-pollution climatology near Monroe, Michigan~* In the present report Hewson, Eo Wo, and Baynton, Ho W,, Air-Pollution Climatology near Monroe, Michigan, UniVo of Micho Engo ResO Insto Report 2442-1-F, Ann Arbor, March 1956. 1

it is investigated further by examining the relationship obetween precipitation occurrences and wind direction for the past winter and springo Before considering the detailed analysis of the data, worthwhile background is provided by noting to what extent the past winter and spring were normal in the broad climatological senseo The winter season was slightly warmer than normal but January alone averaged about 5~F below normal with relatively large snow accumulations. Winds were quite typical of average winter conditionsO The spring began with temperatures somewhat above normal and reached a peak of warmth. toward the end of April with temperatures over 20~F above normal. Thereafter the seasonal warming trend lagged somewhat, with May temperatures averaging slightly below normal. Precipitation for the spring was about normal with deficits in March and May being made up by a large excess in April. Wind speeds through the spring were about normal -but east winds were somewhat more frequent than usual in. May. ANALYSIS OF WIND DATA The present analysis covers data collected during the winter of 1956-57, i.e., December, January, and February; and the spring of 1957, i.e., March, April, and May. As in the first progress report (Jan., 1957), the comparison is made between wind data obtained at 102 ft at the plant site and corresponding data at Detroit City Airport, 81 ft, at Toledo Express Airport, 72 ft, and at Toledo Municipal Airport, 47 ft, for the same months of 1950 to 1954, inclusive. The locations of these four weather stations are shown in Figo 1. The analyzed data are presented in Tables I through VIII in which there is a grouping by seasons, December, January, and February combining to give the winter picture; and March, April, and May combining to give the spring picture. Discussion of the data will follow identically the pattern set in. the first progress report but each season will be treated separately. 1o WINTER SEASON Wind directions may be grouped on the basis of their implications to population centers. Winds from the sector E, ESE, SE, SSE, and S, and the sector W, WNW, NW, NNW, N, and NE will carry for 20 miles or more before reaching any population centers. These two groups of winds will be discussed first. During the past winter, winds from the sector E through S were observed 15.5% of the time at the Enrico Fermi. Plant site, 20.4% at Detroit, and 18,6% at Toledo Expresso During the 5 successive winters beginning in 1950, these winds were observed 21.4% of the time at Toledo Municipalo In this respect the winter seems to have been fairly typical since the variations evident in thbe above data are about what might be expectedo 2

EXRS2 _'/ DETROIT LE CITY r4 LAKE A'R~i~T~ \SR.CLAIR WILL O RUN NAIR PORT "/:NIPAL"'/;,'d /iYX/ -~ —/k ~~ CA NA Ap eow 0~~~~~~~~ i,~~~~~'Fig.o 1. Topographic map of site and surroundingso 5 >;L E ER vadvti n f7 TOLEDO SW LED EXPRESSIFt / MUNICIPAL AIRPORT ~ AIRPORT Fig. 1. Topographic map of siate and surroundings.

TABLE I PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Enrico Fermi Power Plant Site (Aerovane at height of 102 ft) 1 December 1956 - 28 February 1957 (Winter) Speed mph Total Wind 25 Total Observations Men eed Direction 0-3 4-12 13-24 and 4 and N of Over**.*.......-.. _. O r.No. mph,Over Over all Mean N 0,2 1.7 lol 0o6 354 355 70 14.2 107 NNE Oo2 1.o3 1.o7 0o4 304 3o6 71 14,9 112 NE 0,2 1.1 3.9 0.2 502 504 107 16.0 120 ENE 0 3 1.4 lo4 2,8 350 60 12.2 92 E 0o4 1.1 1.3 204 2o7 54 12.0 91 ESE 0.1 1,9 1ol 3.0 0 0 61 1107 88 SE 03 lo17 1 1 2o8 350 60 11o1 84 SSE 0.2 1.2 1.0 2.2 2.3 45 12.0 90 S Oo2 2.0 2,o3 o0 4.4 4.5 90 1353 100 SSW 0.2 3.1 6.1 0.4 9 6 9.7 192 15.2 115 SW 0.2 3o5 7.1 0ol 10o7 10o9 216 15 0 113 WSW 0o2 6.4 7.4 1358 13o9 276 13o5 101 W 0.4 4o5 4o7 0o2 9o4 9.7 193 13.1 99 WNW 0o5 5o0 4.5 o.2 9.7 10o2 202 12o7 96 NW 0.5 4.9 2o6 0ol 7o6 8,1 161 11.2 84 NEW 0.1 3.7 2.0 5. 7 5~7 113 11o6 87 Calm o06 o 6 11 Totals 4.8 44,5 49,53 2,3 96ol 99.8 1982 1353 100 4

TABLE II 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) Speed9 -.h Total Wind 25 Total Observations Mean Speed Direction 0-3 4-12 13-24 and 4 and No. ph of Over~ - % NOo mph * -. Over Over all Mean N 0,7 6.7 358 I0o5 11.2 243 10.4 94 NNE 0.3 2.5 1.2 3.8 4.1 88 10o2 92 NE o 6 1.53 o4 o17 2.3 49 7.7 69 ENE Oo1 2.7 0.4 3o1 352 69 8.9 80 E 0.7 35-3 0.3 36 4.3 93 7.0 63 ESE 0~3 1.4 0.0 lo4 o17 37 6.9 62 SE.ol 2.4 0,1 2.5 2.7 58 6o6 59 SSE Oo.l 55 0,3 358 3~9 85 8,0 72 S 0 o5 51 2 1 7o3 7.8 168 10o1 91 SSW OoO 0 20 28 4.9 4.9 105 12.6 113 SW 0ol 4.7 6o9 0.2 11o8 11.9 257 1353 120 WSW 0o 0 33 3.7 7.0 700 151 12.5 113 W 0ol 5.8 508 003 11. 6 117 253 12.1 109 WNW 0.2 2.5 5.8 Oo1 8.7 8.8 191 14.0 126 NW o5 4,4 356 8o1 8.6 186 116 104 NNW 0.2 2,2 2,8 5,0 5.2 112 12o6 113 Calm 007 0,7 15 Totals 5.2 5359 40,0 0o6 94o8 OO. 2160 11,1 100 5

TABLE III 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 peed m _h Total. S.. Wind 25 Total Observations Mean Speed Direction 0-3 4-12 13-24 and 4 and No mph of Over-, _..........Over Over. p! all Mean N 0.3 351 2.0 5.2 5.5 118 10.8 104 NNE 0.1 2.1 1.4 3.6 3.7 80 11.0 106 NE 0.2 2.6 1.1 3.7 3.9 85 10.0 96 ENE 0.4 2.0 0.7 2.7 3.1 68 9.0 86 E 004 2.4 0.8 3.2 3.6 77 9.1 87 ESE 0.5 2.1 0.3 2.4 2.8 61 7.5 72 SE 004 1.9 1.9 2.3 50 6.o 58 SSE o.6 2.5 0.2 2.7 3.3 71 7.4 71 S 0.4 4.3 1.9 6.2 6.6 142 10.0 96 SSW 0.3 2.9 535 0,2 6.6 6.9 148 12 6 121 SW 0.2 5.5 6.1 0.1 11.8 11.9 258 12.9 124 WSW 0.2 8.8 7.4 0. 1 16.5 357 11.9 114 W 0.1 50. 2.7 8o0 8.1 175 10o8 104 WNW 4.4 200 6.5 6.5 141 10.4 100 NW 0.3 4.8 1.7 6.5 6.9 148 9.9 95 NNW 0.5 3.8 1.4 5.2 5.7 123 9.5 91 Calm 2.7 2.7 58 Totals 7.6 58.5 3352 0.4 92.5 100.0 2160 10.4 100 6

TALBE IV 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 (Winter Season) Speed9 mph Total Mea Wind 25 Total Observations Direction 0-3 4-12 13-24 and 4 and % Noo mph o of OverOver Over all Mean N 0,3 2,3 10 354 356 395 10o1 78 NNE 0.1 1 o8 1 o6 0.1 354 3.6 385 12.4 96 NE 0.2 1.9 1-8 0ol 358 4,0 432 12.3 95 ENE 002 201 2,8 o.4 503 5.5 591 14.3 111 E 0.3 2,6 1.4 4,0 4.3 467 101o 78 ESE 0.2 2.0 0.6 2.5 2.8 301 9.1 71 SE 0.3 2.3 0.7 350 3.3 352 809 69 SSE 0.2 2.2 1.3 536 3,8 411 ll.l 86 s 0.4 3.2 354 0.2 6.8 7.2 777 12.9 100 SSW 0.2 4.8 6.5 o.8 12.1 12,3 1330 14,5 112 SW 0.3 507 71 1.0 13 8 14, 1524 14.1 109 WSW 03, 504 6.6 10 12, 9 1532 1429 14o0 109 W 0,3 3o6 2.9 0.2 6.8 7.2 774 12,1 94 WNW 0.1 2,6 535 0.5 6,7 6.8 732 143, 111 NW 0,2 2,1 2,7 002 5.0 5.3 570 13.5 105 NNW 0.1 1.2 2,2 0.1 2.6 2.7 295 12.5 97 Calm 0 05 05 59 0 Totals 359 45.8 45.1 4,7 95o6 100,0 10824 12.9 100 7

TABLE V PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Enrico Fermi Power Plant Site (Aerovane at height of 102 ft) 1 March 1957 - 31 May 1957 (Spring) Speed, h Total Wind 25 Total Observations Mean Speed Direction 0-5 4-12 13-24 and 4 and. m of OverOver Over all Mean N 0.0 1 41 142 2.6 53 10.2 72 NNE 0.0 2.4 3.4 0.1 5.9, 6.0 121 14.4 103 NE 0.1 1.8 4.8 0.3 6.9 7.0 142 15.9 114 ENE 0.1 2.2 6.7 lol 10.0 10.1 205 16.5 118 E 0.1 1.6 537 1.7 7.0 7.2 145 13.6 97 ESE 0.0 2.6 354 0.1 6.1 6.2 125 14.2 102 SE 0.0 2.4 2.2 0.2 4.8 4.9 99 1356 97 SSE 0.2 4,0 1.8 0.0 5.8 6.1 124 1.1 79 S 0.3 35 1 1.5 4.6 4.9 100 10.9 78 SSW 0.2 350 2.4 o 0 5.4 5.6 113 12.4 89 SW 0.1 2.7 5.1 7.8 7.9 160 14.7 105 WSW 0.3 2.9 4.4 1.6 8.9 93. 188 16.1 115 W 0.1 3.4, 2.4 0.4 6.2 6.3 128 12.8 91 WNW o.o 3.0 6.0 9.0 9.0 183 15.0 107 NW 0.1 1.8 2.5 0.0 4.3 4.5 91 1539 99 NN'W 0.1 1.6 o.6 2.2 2.3 47 10.6 76 Calm O.1 0.2 3 Totals 1,8 39.6 52.5 5o5 97o4 99o9 2027 14o0 100 8

TABLE VI 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, mh TotalMea 2h, _-. ^ Mean Speed Wind 25 Total Observations pe Direction 0-3 4-12 13-24 and 4 and No mph o of OverOver Over. all Mean N o.6 6.2 355 9.7 10,4 228 10.3 93 NNE 0.2 4.3 1.5 5.8 6.0 132 10.2 92 NE 0.8 3.3 1.9 5.2 6.0 133 9.6 86 ENE 0.2 4.6 2.0 6.6 6.8 151 10.2 92 E 0.5 7.7 1.8 9.6 10.2 224 9.5 86 ESE 0.2 2.9 0.9 3.8 4o0 88 9.9 89 SE o.6 3.8 0.5 4.3 4.9 109 7.4 67 SSE 0.1 2.4 0.9 3.4 3.4 76 9.3 84 S 0.2 7.1 1.5 8o6 8.9 195 9.0 81 SSW 1.7 1.6 3.53 34 74 10.3 93 SW 1.4 3.8 1.0 6.2 6.2 137 15.0 135 WSW 1.3 2.7 0.3 4.3 43. 96 15.6 141 w 0.4 3.8 4.0 0.4 83. 8.6 192 31.0 117 WNW 0.1 2.1 4.7 0.3 7.1 7.2 158 14.8 133 NW 002 352 3.4 6.7 6.9 152 12.2 110 NNW 1.2 1.0 2.1 2.1 47 12.1 109 Calm 0.7 0.7 16 Totals 4.8 57.1 355.7 2.1 95.0 100.0 2208 11.1 100 9

TABLE VII PERCENTAGE FREQUENCY OF OCCURRENCE OF WINDS IN VARIOUS DIRECTIONS GROUPED ACCORDING TO WIND SPEEDS Toledo Express Airport (Wind instrument at height of 72 ft) 1 March 1957 - 31 May 1957 (Spring) Speed mph TotalMean............ Mean Speed Wind 25 Total Observations Direction 0-5 4-12 13-24 and 4 and No mph of Over_..__...Over _Over Overall Mean N 0.1 354 1.5 4.8 4.9 109 9.9 82 NNE 0.2.53 23. 5.6 5.8 129 11.2 92 NE 0.3 4.0 1.7 5.7 5.9 131 10.0 83 ENE 0.1 4.6 4.3 0.1 9.0 9.1 202 12.2 101 E 0.3 5.0 43. 0.4 9.8 10.1 222 12.5 103 ESE 004 3.2 0.6 3.8 4.2 92 8.6 71 SE 0.2 1o6 0.4 1.9 2.1 47 9.0 74 SSE 0.1 2.6 1.6 4.3 4.4 97 11.5 95 S 3.8 2.2 6. 6.00 133 10.9 90 SSW 2.2 2.0 0.1 43. 43. 94 12.9 107 SW 2.5 5.4 o.6 8.5 8.6 189 15.4 127 WSW 0.2 3.8 4.8 1.6 10.1 l0.4 229 163. 135 W 0.1 4.9 2.8 0.2 8.0 8.1 178 11.9 98 WNW 0.2 4.3 3.2 7.6 7.7 171 11.4 94 NW 0.2 2.7 1.9 406 4.8 106 11.0 91 NNW 0.2 1.9 1.0 2.9 3.1 69 9.7 80 Calm 0,5 0.5 10 Totals 35.1 535.8 40,0 35.0 96.9 i00o0 2208 12.1 100 10

TABLE VIII 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 Season) Speed, mph Total Mean Speed Wind 25 Total Observations Direction 0-3 4-12 15-24 and 4 and | No mph of OverOver Over all Mean N 0.3 2,9, O 3.9 4.2 468 9.1 72 NNE 0.1 1.9 1.2 301 3.2 351 11.1 87 NE 0.2 3.0 2.7 5.8 6.0 667 11.8 93 ENE 0.2 4.1 6.5 0.7 11.2 11.4 1258 14.6 115 E 0.4 3.8 3.0 0.1 6.9 73. 811 1i.4 90 ESE 0.2 2.2 0.7 3.0 3.2 350 9.4 74 SE 03. 2.3 0.5 2.7 3.0 332 8.4 66 SSE 0.2 1.8 0.9 0.1 2.7 2.9 323 11.0 87 S 0.3 2.9 1.8 0.2 4.9 53. 582 11.7 92 SSW 0.2 351 3.5 0o4 7.0 7.2 796 13.7 108 SW 0.4 4.8 4.4 0.7 9.8 10.2 1127 1303 105 wsw 0.3 4,2 5.4 o.9 10o4 10.8 1189 14.3 113 W 0.2 3.6 3,7 0.4 7.7 8.0 881 13.4 106 WNW 0.3 2.4 4.7 0.4 7.6 7.8 865 14.9 117 NW 0.1 2.2 3,1 03. 5.6 5.8 636 14. 110 NNW 0.2 1.7 o.8 0.1 2.6 2,8 307 10.6 83 Calm 0 0.9 9 97 0 Totals 359 46,9 435.9 4.5 95.2 100.0 11040 12,7 100 11

.Winds from the sector W through MNE were observed 40.8% of the time at the plant site, 49.6% at Detroit, and 36.4% at Toledo Expresso During the 5 winters 1950-54, these same winds were observed 29.2%o of the time at Toledo Municipal. Winds from this sector appear to have been more frequent than usual during the past wintero Combining the two groups of directions gives a total of 56.53% at the plant site,.70.0% at Detroit, 55.0% at Toledo Express, and 50.6% at Toledo Municipal, For reasons discussed in the first progress report, the data for Detroit do not appear to be representativeo Based on the plant site and Toledo Express figures, which are in good agreement, it follows that, 55. 6 of the time, winds from the plant site would have carried 20 miles or more before reaching population centers The remaining wind directions are discussed in relation to the implicated population centerso ENE Monroe. —During ENE winds Monroe is downwind from the plant site0 ENE winds occurred at 350% of the time at the plant site, 3.2% at Detroit, 3o1% at Toledo Express, in comparison with 5.3% at Toledo Municipal for the earlier 5year period, thus confirming the infrequency of these winds at this season. SSW - Detroit River communities.-SSW winds blow from the plant site towards the Detroit River communities. The corresponding percentages of SSW winds are: plant site, 9.7; Detroit, 4.9; Toledo Express, 6.9; and Toledo Municipal for 5 years, 12.1. Without including the Detroit data which may be unrepresentative, SSW winds appear to have been less frequent than usual. SW and WSW - Ontario shores. —.SW and WSW winds at the plant site cross Lake Erie to Ontario. However, with the lake acting as a heat source, strong lapse rates would tend to develop in crossing the lake, and good diffusion conditions would result. The following percentages of winds from SW and WSW were observed24.8,%at the plant site, 18.9% at Detroit, 28.4% at Toledo Express, and 26.7 at Toledo Municipal in the earlier 5-year periodo Wind speeds at the plant site, Detroit, and Toledo Express have been compared for evidence of special lake influenceso Figure 1 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 tcomparisons between wind speeds for corresponding directions at the three stations are meaningless because of different heights of anemometer exposure and differences in instrumentation. However, if mean wind speeds for each direction are first expressed as a percentage of the overall mean wind speed for all directions, comparisons may then be made. For example, during the spring of 1957 the mean wind speed at the plant site was 14o0 miles/hro The mean wind speed for WNW winds was 15.0 miles/hr or 107% of 14.0 miles/hr. Computations of this sort have been made for all wind directions for the three stations and appear as the last column of Tables I through VIII (see also Figs. 2 and 3). The results of the analysis are presented in Fig. 4. Toledo and Detroit have been combined into a single curve for comparison purposes. At the plant site, 12

N N ~/ /-15 % a mph /15 % a mph Wa XNE W-' NE s I W - E SW SE S S TOLEDO MUNICIPAL AIRPORT DETROIT CITY AIRPORT (Instrument Exposure at 47 feet) (Instrument Exposure at 81 feet) DEC., JAN, FEB., 1950-1954 I DEC. 1956 - 28 FEB. 1957 N N ~N "~' ^15 0/o mph 15 /a mph NW/' /,.~ O NE NWx"'NE W,E X, 0.. E SW E, W E S S TOLEDO EXPRESS AIRPORT ENRICO FERMI POWER PLANT (Instrument Exposure at 72 feet) (Instrument Exposure at 102 feet) I DEC. 1956- 28 FEB. 1957 I DEC. 1956- 28 FEB. 1957 Fig. 2. Percentage frequency of occurrence of winds from 16 directions (rectangles) and corresponding wind speed in mph (heavy lines) at Municipal and Express Airports at Toledo, Ohio, Detroit City Airport and Enrico Fermi Power Plant, Winter. Percent of calms in center. 15

N,"515 % a mph 15 % 8 mph W. 9 E W.7, E S S TOLEDO MUNICIPAL AIRPORT DETROIT CITY AIRPORT (Instrument Exposure at 47 feet) (Instrument Exposure at 81 feet) MAR., APR., MAY, 1950-1954 I MARCH - 31 MAY, 1957 N N 1 5 ^15%% El mp h /< /'15% & mph Mfl >NNW NE r N1 E W L', ^E -W - E W E ~~~~~~SWT YSw E/ S S TOLEDO EXPRESS AIRPORT ENRICO FERMI POWER PLANT (Instrument Exposure at 72 feet) (Instrument Exposure at 102 feet) I MARCH - 31 MAY, 1957 I MARCH - 31 MAY, 1957 Fig. 3. Percentage frequency of occurrence of winds from 16 directions (rectangles)and corresponding wind speed in mph (heavy lines) at Municipal and Express Airports of Toledo, Ohio, Detroit City Airport and Enrico Fermi Power Plant, Spring. Percent of calms in center. 14

140 -- WATER TRAJECTORY z 130 — _ d K30 <AT MONROE t) d 120 -- a. / =n _...-.,,,.,.-.... 10 Id -I Z 80 -1 -_A J //....'TOLEDO combined, for various directions, expressed as a percentage of the overall mean winter wind speed. 70 DETROIT TOLEDO 50. N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Fig. 4. Mean wind speed at Enrico Fermi Power Plant site and Detroit-Toledo combined, for various directions, expressed as a percentage of the overall mean winter wind speed.

those winds which are off the lake are seen to be relatively stronger than the same winds at Detroit and Toledoo Both the tendency for strong lapse rates over the lake in winter and the smoothness of the lake surface contribute to this resulto However, it remains for later analysis to show whether the same result is obtained in the summer when inversions over the lake become the rule. SPRING SEASON During the spring of 1957, the percentages of winds from the sector E through S were as follows: plant site, 29.3; Detroit, 31.o4 Toledo Express, 26.8. These may be compared to 21o7 at Toledo Municipal for the 5 springs 1950-54o The high frequency of E during May has contributed to the high totals obtained in 1957. The percentages of winds from the sector W through MNE were as follows: plant site, 30.7; Detroit, 41.2; Toledo Express, 34.4. These are in fair agreement with the 5-year average of 31.8 at Toledo Municipalo Combining these two groups, the percentages are as follows: plant site, 59.9; Detroit, 72.6; Toledo Express, 61.2; and for the 5-year period at Toledo Municipal, 5355. Thus it is seen that these wind directions were unusually frequent during the spring of 1957. ENE - Monroe.-The frequencies of these winds were as follows: plant site, 0lo1; Detroit, 6.8; Toledo Express, 9.1. This is two to three times as frequent as the same wind direction in the past winter but compares closely to the 11.4 for spring during the 5-year period at Toledo Municipal. SSW - Detroit River communities. -Winds from the SSW were observed 5o6% at the plant site, 354 at Detroit, 4.3 at Toledo Express, or in general rather less than the 5-year average of 7.2% at Toledo Municipal. SW, WSW - Ontario shoreso-The frequencies f'these winds were as follows: plant site, 17.2; Detroit, 10. 5; Toledo Express, 19.0, or somewhat less than the 5-year average of 21oO at Toledo Municipalo However, disregarding the Detroit data which do not appear to be representative, the values are fairly typical of spring. Since the lake surface is relatively cold during the latter part of the spring, poor diffusion conditions would often occur as these winds carried across the lake. Wind speeds were compared, in the manner described earlier for the winter analysis, in an attempt to detect special lake influences. In Figo 5 winds off the lake at the plant site are again seen to be stronger than the corresponding winds at Detroit and Toledo combinedo The effect of the smoothness of the lake surface evidently outweighs the influence of inversions over the relatively cold lake surface. Since the latter effect will be more pronounced in summer, this type of comparison may then yield different resultso

150 - -...'i....... —WATER TRAJECTORY 140 -"... AT MONROE, 130 __.__ z 120 100 / ______._ z - w 90 C, z < 70-___ DETROIT 60 MONROE 50I - -- N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Fig. 5. Mean wind speed at Enrico Fermi Power Plant site and Detroit-Toledo combined, for various directions, expressed as a percentage of the overall mean spring wind speed. mean spring wind speed.

ANALYSIS OF TEMPERATURE-LAPSE-RATE DATA 1o CLASSIFICATION OF LAPSE-RATE DATA The temperature-lapse-rate data were recorded at the 1OO-ft meteorological tower on the Enrico Fermi Plant site. Lapse rates during each hour are classifled as strong, weak, or inversionso Strong lapse rates are those values in excess of the dry adiabatic lapse rate; positive lapse rates that are less than the dry adiabatic rate are classified as weak; and negative lapse rates, ie,,, tenmperature increasing with height, are classified as inversions. Generally speaking, strong lapse rates, weak lapse rates, and inversions are associated with above average, average, and below average diffusion conditions, respectively. Strong lapse rates are indicative of turbulent air motion and hence indicate good diffusion conditions. Inversions tend to suppress turbulent air motion and thus inhibit diffusiono The moderating influence of Lake Erie at the Enrico Fermi Plant site has been previously discussed on a theoretical basis. To evaluate this influence, temperature-lapse-rate data from the WJBK-TV tower, in the northwest section of Detroit, have been compared with the data recorded at the Enrico Fermi Plant site. Tables IX and X summarize the lapse-rate data from the two sites. At both locations inversions were observed more frequently in winter than in spring. The incidence of inversions at the Detroit tower site is greater during both winter and spring than that experienced at the Enrico Fermi Plant site. 2o INVERSION CONDITIONS The duration of inversions is also importanto In the compilation of data for the tables of continuous inversions (Tables XI-XIV) an occurrence of one hour of weak lapse rate within a group of inversions was not considered a break in the continuous inversiono For example, six continuous hours of inversions followed by a one-hour weak lapse rate and then five more hours of inversions would be considered twelve hours of continuous inversions. This interpretation assumes that one hour of weak lapse rate would not materially alter the diffusion-regimeo During winter, inversions lasting more than five hours are more frequent at the Detroit location but the average length of the inversions is considerably longer at the Enrico Fermi Plant site. Spring conditions indicate a slight change from the winter situation in that both the frequency of occurrence and the average length of these Inversions is greater at the Enrico Fermi Plant site. The most important difference between the two sites is the frequency of inversions persisting for over 25 hr in duration at the Enrico Fermi Plant site. Inversions of 50-, 40-, and 60hr duration are important and careful consideration is required to estimate their frequency and extreme valueso 18

TABLE IX SUMMARY OF TEMPERATURE-LAPSE-RATE DATA AT THE ENRICO FERMI POWER PLANT SITE 1 December 1956 - 28 February 1957 and 1 March 1957 - 31 May 1957 Winter Spring Total Total hours 2160 2208 4368 Number missing hours 516 168 684 Number hourly observations 1644 2040 3684 Percent missing data 23o9% 7o6% 15 7% Percent inversions 20o9 18o3 19o4 Percent strong lapse 31o4 72o0 53o9 Percent weak lapse 4 77 9o7 26,7 100ooo lo00o0 100o.0 TAB LE X SUMMARY OF TEMPERATURE-LAPSE-RATE DATA (INVERSIONS) AT THE WJBK-TV TOWER, DETROIT 1 December 1956 - 28 February 1957 and 1 March 1957 - 31 May 1957 Winter Spring Total Total hours 2160 2208 4368 Number missing hours 664 426 1090 Number hourly observations 1496 1782 3278 Percent missing data 30 7% 19. 3 25 0% Number hours inversions 393 388 78l Percent inversions 26o3% 2108% 2358% 19

TABLE XI FREQUENCY OF CONTINUOUS INVERSIONS AT THE ENRICO FERMI POWER PLANT SITE 1 December 1956 - 28 February 1957 (Winter) Duration9 hr_ 6to 12 13 to 24 25 and Over H Mean Speed, H Mean Speed 9 Hr Mean Speed, Hr mph Hrmph Hr h _______ niph ___________ igpn _........ mph..... 8 13 18 9 58 17 6 6 14 9 43 14 12 3 16 12 10 12 16 18 6 7 18 9 10 7 20 6 8 13 17 5 Total number of inversions over 5 hr in duration = 16 Total hours of continuous inversions over 5 hr in duration = 280 Average length of continuous inversions over 5 hr in duration = 17o5 20

TABLE XII FREQUENCY OF CONTINUOUS INVERSIONS AT THE WJBK-TV TOWERS DETROIT 1 December 1956 - 28 February 1957 (Winter) Duration, hr 6 to 12 13 to 24 25 and Over 7 16 8 15 6 17 11 14 7 15 7 15 7 20 7 19 10 19 7 16 9 15 11 10 Total number of inversions over 5 hr in duration = 24 Total hours of continuous inversions over 5 hr in duration = 286 Average length of continuous inversions over 5 hr in duration = 11o9 21

TABLE XIII FREQUENCY OF CONTINUOUS INVERSIONS AT THE ENRICO FERMI POWER PLANT SITE 1 March 1957 - 31 May 1957 (Spring) Duration, hr 6to 12 13 to 2 25 and Over Hr Mean Speed, Hr Mean Speed, Hr Mean Speed, mph h mph 10 9 19 11 34 17 7 8 13 20 26 9 12 14 18 12 8 16 19 16 6 13 17 8 6 14 15 7 6 8 14 11 6 10 6 12 6 13 6 10 6 6 9 7 9 10 7 17 Total number of inversions over 5 hr in duration = 24 Total hours of continuous inversions over 5 hr in duration = 285 Average length of continuous -inversions over 5 hr in duration = 11t9 22

TABLE XIV FREQUENCY OF CONTINUOUS INVERSIONS AT THE WJBK-TV TOWER, DETROIT 1 March 1957 - 31 May 1957 (Spring) Duration, hr 6 to 12 13 to 24 25 and Over 9 14 7 13 6 14 12 14 7 15 11 11 il 7 11 9 9 11 11 11 10 11 12 6 9 8 12 9 7 9 9 Total number of inversions over 5 hr in duration = 30 Total hours of continuous inversions over 5 hr in duration = 304 Average length of continuous inversions over 5 hr in duration = 10.1 23

5. ASSOCIATION OF LAPSE RATES WITH WVIND DIRECTIONS The association of lapse rates with wind directions is summarized in Tables XV and XVI. The first grouping of columns indicates the frequency of observed strong, weak, and inversion lapse rates associated with the winds from the indicated compass directions. The remaining columns provide relative frequency data and are classified in two ways. The first grouping is based on the relative frequency of occurrence within a given category for a specified direction. For example, 0.9% of the observations of strong lapse rates, during the winter period, were associated with winds from a north direction (Table XV)o The second classification indicates the percent of the total observed data that had the characteristics of a north wind and a strong lapse rateo For example, in 0.2% of all the observations a north wind occurred simultaneously with a strong lapse rate (Table XV). Figures 6 and 7 are a graphic representation of the relative frequency of occurrence of winds associated with inversions and noninversions during the winter and spring months at the Enrico Fermi Plant site. The original data for these graphs are summarized in Tables XVII and XVIII. ANALYSIS OF PRECIPITATION DATA Since the cessation of most of the heavy blasting at the Enrico Fermi Plant site, it is now possible to make an analysis of the precipitation data that are being collected. The first progress report outlined the precipitation instrumentation that is being used at the plant site. It might be well to mention at this time that the weighing rain gage at the Enrico Fermi Plant site has a threshold value of 0002 in. These data are being compared with those of Toledo Express whose tipping-bucket rain gage has a threshold value of 0.01 in. As a result, there may be -some differences when comparing the number of observations ofr-tieasurable precipitation. The weighing rain gage at the Enrico Fermi Plant site is being used because it operates successfully without attention during freezing weather whereas other types of rain gages freeze and become inoperative or require constant attention. The Toledo Express data are being used as a basis of comparison since the original evaluation of the air-pollution climatology near Monroe, Michigan, used climatological data from Toledo Municipal. The analysis of the precipitation data will be divided into the winter and spring seasons as has been done with the other weather elements. Tables XIX through XXIV present the precipitation data from the Enrico Fermi Plant site and the Toledo Express for the same period, and five years of data from Toledo Municipal for the same seasons (see also Figs. 8 and 9). These tables show, for 16 wind directions, the number of hours that measurable rain occurred, the hours of precipitation as a percentage of the total number of hours of precipitation, and also the hours of precipitation as a percentage of the total numbers of hours in the seasono 24

TABLE XV THE ASSOCIATION OF TEMPERATURE LAPSE RATES WITH WIND DIRECTION AT THE ENRICO FERMI POWER PLANT SITE 1 December 1956 - 28 February 1957 (Winter) Percent Frequency of Lapse Rates Hourly Lapse Rates Wind oy Lase as Compass Observations Total Direction W I Totals Within Cate ories Observations S W I S W I N 3 42 12 57 0.9 5.4 3.5 002 2.6 0.7 NNE 7 43 12 62 1.4 5.5 3.5 0.4 2.6 0.7 NE 19 65 9 93 3.7 83. 2.6 1.2 4.0 0.5 ENE 19 22 15 56 307 2.8 4.4 1.2 1.3 0.9 E 16 14 18 48 3.1 1.8 5.2 1.0 0.9 1.1 ESE 21 21 19 61 4.1 2.7 5 15 1.3 12 12 SE 7 22 32 61 1.4 2.8 93. 0.4 13. 1.9 SSE 7 13 20 40 1.4 1.6 5.8 0.4 0.8 1.2 S 32 23 19 74 6.2 2.9 5.5 1.9 1.4 1.2 SSW 53 65 52 170 10o3 8.3 15.2 3.2 4.0 3.2 SW 82 49 49 180 15.9 6.2 143. 5.0 3.0 3.0 WSW 120 108 29 257 23.2 13.7 8.4 7-3 6.6 1.8 W 47 69 23 139 9.1 8.8 6.7 2.9 4.2 1.4 WNW 41 86 11 138 7.9 11o0 3.2 2.5 5.2 007 NW 19 80 13 112 3.7 10.2 3.8 1.2 4.9 0.8 NNW 17 59 9 85 3~3 7.5 2.6 1.0 3.6 0.5 Calm 6 4 1 11 1.2 0.5 0.3 0.4 0.2 0.1 Totals 516 785 343 1644 100.5 100.0 99.8 31.5 47.9 20.9 C~de: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. 25

TABLE XVI THE ASSOCIATION OF TEMPERATURE LAPSE RATES WITH WIND DIRECTION AT THE ENRICO FERMI POWER PLANT SITE 1 March 1957 - 31 May 1957 (Spring) Hourl Lapse Re. Percent Frequency of Lapse Rates Win Hourly Lapse Rates To Wind Ho ya R Compass Observations Total Direction Totals Within Categories Observations',w, I, _!S W I S W I N 44 3 7 54 350 1.5 lo9 2.2 0,1 003 NNE 105 4 14 123 7.1 2.0 3,8 5.1 0.2 0.7 NE 126 5 6 137 8.6 2.5 1.6 6.2 0.2 0.3 ENE 194 4 4 202 1352 2.0 1.1 9.5 0.2 0.2 E 129 7 8 144 8.8 305 2,1 6.3 03. 0o4 ESE 99 9 25 133 6.7 4.5 6.7 4.9 0o4 1,2 SE 50 7 43 100 304 305 11.5 24 0.3 2.1 SSE 40 11 63 114 2,7 5.6 16.9 2o0 0.5 3.1 S 24 16 58 98 1.6 8,1 15o5 1.2 0.8 2,8 SSW 51 13 47 111 305 6.6 12.6 2.5 o06 2,3 SW 121 39 22 182 8,2 19,7 5.9 5.9 1.9 11o WSW 132 23 24 179 9o0 11o6 6.4 6.5 1.1 1.2 W 99 21 14 134 6.7 10.6 3.8 4.9 lo0 0.7 WNW 156 15 19 190 10o6 7o6 5o1 7.6 0.7 0.9 NW 74 12 7 93 5.0 6,1 1.9 3.6 o.6 0.3 NNW 25 9 11 45 1o7 4,5 2.9 1.2 0o4 0,5 CalOm 0 0 1 1 0. 0 0.0 053 0.0 0.0 0,0 Totals 1469 198 373 2040 99 8 99o9 100o0 72.0 953 18,l Code' C S = A lapse rate in excess of the dry adiabatic lapse rateo W = A positive lapse rate that is less than the dry adiabatic lapse rate. I = A temperature increase with heighto 26

TABLE XVII MEAN WIND SPEEDS ASSOCIATED WITH INVERSION AND NONINVERSIONS AT THE ENRICO FERMI POWER PLANT SITE 1 December 1956 - 28 February 1957 (Winter) Wind Inversion Noninversion Dirtion OccurreOccurrence, Mean Speed, Ocurrence, Mean Speed, Direction * m I mph N 0.7 5.8 2.7 15.9 NNE 0.7 7.0 350 16,5 NE 0.5 10.9 5.1 16.5 ENE 0.9 12.8 2.5 12.0 E 1.1 11.8 1.8 12.1 ESE 1.2 11.8 2.6 11.6 SE 1.9 10.2 1.8 12.1 SSE 1.2 10.7 1.2 13.0 S 1.2 11.6 303 13.8 SSW 3.2 14.2 7.2 16.6 SW 3.0 15.8 8.0 14.8 WSW 1.8 14.1 13.9 13.5 W 1.4 11.2 7.1 13.4 WNW 0.7 9.1 7.7 13.0 NW 0o8 7.4 60. 11.7 NNW 0.5 6.2 4.6 12.1 Calm 0.1 0.6 Period Total 20.9 79.1 Period Average 11.7 13.6 27

TABLE XVIII MEAN WIND SPEEDS ASSOCIATED WITH INVERSION AND NONINVERSIONS AT THE ENRICO FERMI POWER PLANT SITE 1 March 1957 - 31 May 1957 (Spring) Wi Inversion Noninversion Wind Direction Occurrence, Mean Speed, Occurrence, Mean Speed, mph mph N 0.3 6.9 2.3 10.7 NNE 0.7 7.7 503 15.3 NE 0.3 8.0 6.4 16.3 ENE 0.2 9-0 9.7 16.7 E 0.4 11.5 6.7 13.7 ESE 1.2 16 o 5 3 13.8 SE 2.1 14.7 2.8 12,8 SSE 3.1 12.2 2 5 10.0 S 2.8 11.0 2.0 10.8 SSW 2.3 10.7 3.1 13.6 SW 1.1 12.4 7.8 15.2 WSW 1.2 9o0 7 6 17.1 W 0.7 10.0 5.9 13.1 WNW 0.9 10.9 8.4 15.5 NW 0.3 7.0 4.2 14.4 NNW 0.5 8.5 1.7 11.3 Calm Period Total 18.1 81.7 Period Average 11.4 14.6 28

NONINVERSIONS INVERSIONS t N NW NE NW NE 15 %\ mph 15 % mph W --- EW — 10 — -0 PO w_ EV w w E SW SE SW SE S S Fig. 6. Percentage frequency of occurrence of winds associated with inversions and noninversions from 16 directions (rectangles) and corresponding wind speeds in mph (heavy lines) at Enrico Fermi Power Plant site, Winter (December 1, 1956 - February 28, 1957). Percentage of calms in center.

NONINVERSIONS INVERSIONS N N NWi N E NW NE 15 % a mph 15% ow N. /./E W E SW L SE SW SE S S Fig. 7. Percentage frequency of occurrence of winds associated with inversions and noninversions from 16 directions (rectangles) and corresponding wind speeds in mph (heavy lines) at Enrico Fermi Power Plant site, Spring (March 1, 1957 - May 31, 1957). Percentage of calms in center.

TABLE XIX THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE ENRICO FERMI POWER PLANT 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 mph Precipitation Precipitation Hours N 14.2 20.6 9 7.6 004 NNE 14.9 17.8 14 11.9 o.6 NE 160. 22.4 17 14.4 0.8 ENE 12.2 9.1ol 8 6.8 0.4 E 12.0 7.1 7 5.9 053 ESE 11.7 10.8 4 3.4 0.2 SE 11.1 11.0 5 4.2 0.2 SSE 12.0 14.0 1 0.8 o 1 S 133 14.4 5 4.2 0.2 SSW 15.2 15.9 14 11.9 o.6 sw 15.0 8.0 3 2.5 O.1 WSW 13.5 1.1 15 12.7 0. 7 W 13.1 6.8 6 5.1 0.3 WNW 12.7 7. 3 3 2.5 0.1 NW 11.2 12.7 3 2.5 0.1 NNW 11.6 18.5 4 3.4 0.2 Calm 0.0 0.0 0 00 0.0 Totals 1353 14.5 118 100.0 5.3 31

TABLE XX 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 10.0 13.3 22 12.5 1.0 NNE 11.0 12.2 20 11.4 0.9 NE 10.0 13.1 14 8.0 0,6 ENE 9.0 11.0 9 5.1 0.4 E 9.1 7.6 8 4.5 0.4 ESE 7.5 4.8 3 1.7 0.1 SE 6.0 5.7 3 1.7 0.1 SSE 7.4 6.2 5 2.8 0,2 S 10.0 11.3 11 6.3 0.5 SSW 12.6 12.8 21 11.9 1.0 sw 12.9 12.4 18 10.2 0.8 WSW 11.9 9.7 16 9.1 0.7 W 108 9.2 5 2.8 0.2 WNW 10.4 8.5 8 4.5 0.4 NW 9.9 6.8 6 3.4 0.3 NNW 9.5 10.5 5 2.8 0.2 Calm 0.0 0.0 2 1.1 0.1 Totals 10.4 9.7 176 100.0 7 9 32

TABLE XXI THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO MUNICIPAL AIRPORT 1 January 1950 - 31 December 1954 (Winter Season) 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 15.6 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 13.9 6o 5.5 0o6 S46 16 l0L6 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 14.5 32 2.9 0.3 NW 14.3 47 4.3 0.4 NNW 13.5 29 2.6 0.3 Calm 0.0 2 0.2 0.0 Totals 14.3 1096 100.0 10.1 33

TABLE XXII THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE ENRICO FERMI POWER PLANT 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 m.ph_ Precipitation Precipitation Hours N 10.2 5.3 5 1.6 0.1 NNE 14.4 14.3 9 4.7 0o.4 NE 15.9 15.3 9 4.7 o.4 ENE 16.5 18.9 36 18.7 1.6 E 15.6 25.5 58 19.7 1.7 ESE 14.2 15.7 8 4.1 0o4 SE 13.6 17.1 20 10.4 0.9 SSE 11.1 13.5 12 6.2 0.5 S 10.9 9.7 6 5.1 0.5 SSW 12.4 12.4 8 4.1 0.4 SW 14.7 14.5 10 5.2 0.5 WSW 16.1 14.8 9 4.7 0.4 W 12.8 15.5 2 1.0 0.1 WNW 15.0 17.2 20 10o4 0.9 NW 13.9 12.0 3 1.6 0.1 NNW 10.6 0.0 0 0.0 0.0 Calm 0.0 0.0 0 0.0 0.0 Totals 14,0 1707 195 100o 0 8,7 54

TABLE XXIII 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 0.1 NE 11.2 9.0 1.6 7.9 007 NE 10.0 9.5 16 7.9 0.7 ENE 12.2 11.4 30 14.9 1.4 E 12.5 14.2 54 26.7 2.4 ESE 8.6 8.6 6 3.0 03. SE 9.0 93. 4 2.0 0.2 SSE 11.5 12.4 14 6.9 0.6 S 10.9 10.1 14 6.9 o.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 10o6 10 5.0 0.5 NW 11.0 11.5 8 4.0 0.4 NNW 9.7 Calm Totals 12.1 13.1 202 100.0 9.2 35

TABLE XXIV THE ASSOCIATION OF PRECIPITATION WITH WIND AT THE TOLEDO MUNICIPAL AIRPORT 1 January 1950 - 31 December 1954 (Spring Season) Average No. of Hours of Precipitation Wind Wind Observations as Percentage of Direction Speed, During Total Hours of Total mph PreciptoPrecipitation Pre it on Hours N 1303 26 2.7 0.2 NNE 14,0 34 355 003 NE 13.9 69 7.1 o.6 ENE 16.3 193 19.8 1.7 E 5134 98 10o1 0.9 ESE 14,5 44 4.5 0,4 SE 11.6 40 4.1 004 SSE 14,0 49 5.0 0,4 S 14.6 49 5.0 004 SSW 154 7 75 0.7 SW 14,8 84 8.6 0.8 WSW 16.4 46 4,7 o04 W 14.3 45 4.6 0.4 WNW 15.5 57 5.9 0.5 NW 16.6 40 4.1 0,4 NNW 11.5 23 2,4 0,2 Calm 0.0 4 0.4 0.0 Totals 14o7 974 100.0 8,8 36

wN^ N 1.5% 1.5 % / /-NW- NE NWX -- - N Oft.% w t E Wi DE E swK SE SWV 1/ E S s TOLEDO MUNICIPAL AIRPORT TOLEDO EXPRESS AIRPORT DEC., JAN.,FEB., 1950-1954 I DEC. 1956- 28 FEB. 1957 7.5 NW NEN ENRICO FERMI POWER PLANT I DEC. 1956- 28 FEB. 1957 Fig. 8. Percentage of total winds associated with precipitation from each direction at Enrico Fermi Power Plant site, Toledo Express Airport, and Toledo Municipal Airport, Winter. 37

NW ^ ->I.NE NWIE IN NEWN S S TOLEDO MUNICIPAL AIRPORT TOLEDO EXPRESS AIRPORT MAR.,APR.,MAY, 1950-1954 I MAR. 1957- 31 MAY 1957 N m/ ^ -— ^1 0 EI.O S ENRICO FERMI POWER PLANT I MAR. 1957- 31 MAY 1957 Fig. 9. Percentage of total winds associated with precipitation from each direction at Enrico Fermi Power Plant site, Toledo Express Airport, and Toledo Municipal Airport, Spring. 38

1. WINTER SEASON A grouping of wind direction will be used as in previous sections. The winds from the E, ESE, SE, SSE, and S and from the W, WetNW, NW, NNW, N, and NE travel 15-20 miles from the Enrico Fermi Plant site before reaching any population center. Over a 15- to 20-mile trajectory the scavenging action of precipitation removes a substantial proportion of suspended particulate matter,* These two groups of wind directions and precipitation occurred 2.7% of the time during the winter season at the Enrico Fermi Plant site, 3.1% at Toledo Express and 5o9% at Toledo Municipal for the 5-year period. The Enrico Fermi Plant site and Toledo Express figures are less than those of the Toledo Municipal because this winter was a relatively dry one; rainfall was 0.98 in. less than the normal over the three-month period. This suggests that precipitation combined with these winds would usually be more frequent than this year. ENE - Monroe.-ENE winds blow from the plant site, a distance of 8 miles to Monroe. Rainfall removes a significant amount of suspended particulate matter in an 8-mile trajectory. ENE winds together with rain occurred 0.4% of the time this past winter at the plant site, and 0.6% at Toledo Express in comparison with 1.5% at Toledo Municipal for the 5-year period. SSW - Detroit River communities.-The plant site is SSW of the Detroit River communities from 10-30 miles distance. Precipitation and SSW winds occurred 0.6% of the time at the Enrico Fermi Plant site, 1.0% at Toledo Express, and 1.1% at Toledo Municipal for the 5-year period. Ontario shores.-The near shore of Ontario extends from a point 10 miles NE of the plant site to a point 1.8 miles ENE of the plant site. Winds from the SW to WSW travel from the plant site to this shore. Precipitation and SW or WSW winds occurred 0.8O of the time at the Enrico Fermi Plant site during the winter season, and 105% at Toledo Express in comparison with 1.1% at Toledo Municipal for the 5-year period. 2, SPRING SEASON The spring season of 1957 was also relatively dry; March precipitation was 1.75 in. below normal, April, 0.99 in. above normal, and May, 0O76 in. below normal for a total spring deficit of 1.52 in. The same method of wind groupings will be used as previouslyo The winds from E' through SE to S and W through NW to E together with rain occurred 3.8% of the time at the Enrico Fermi Plant site, and 4.1% at Toledo Express in comparison with 2.5% at Toledo Municipal for the 5-year period. For a more detailed and theoretical account of the scavenging effect of rainfall, see Greenfield, So M,, "Rain Scavenging of Radioactive Particulate Matter from the Atmosphere," J. Meteorology, 14, 115-125 (1957), in particular Fig. 1. 39

ENE- Monroe.-The combination of precipitation and ENE winds occurred 1.6% of the time at the plant site, 1.4% at Toledo Express and 1.7% at Toledo Municipal for the 5-year period. NE - Beaches.-Towards the end of spring, the beaches become a population center. During NE winds they are downwind from the plant site. In the spring of 1957, NE winds together with rain occurred 0.4% of the time at the Enrico Fermi Plant site, and 0o7% at Toledo Express, compared with 0.6% at Toledo Municipal in the 5-year periodo SSW - Detroit River communities o-At the Enrico Fermi Plant site the combination of precipitation and SSW winds occurred 0.4% of the time, 0.5% at Toledo Express, and 007% at Toledo Municipal for the 5-year period. SW and WSW - Ontario shoresoThe combination of these winds and precipitation occurred 0.9% at the Enrico Fermi Plant site, and 0.7% at Toledo Express in comparison with 1.2% at Toledo Municipal for the 5-year periodo CONCLUSIONS Twofold evidence of the special lake influences on the Enrico Fermi Plant site has come to light in the analysis to dateo First it has been shown that winds become relatively stronger over the lake in winter and spring. This is a favorable influence on diffusion. Secondly it has been shown that surface temperature inversions lasting longer than a day are not unusual at the plant site, whereas such lengthy inversions are not observed at all at Detroit. This is an unfavorable influence upon diffusion. The diffusion studies over the lake, planned for the summer of 1958, will help reveal the implications of these prolonged inversions. The special influences noted above must be identified with winter and spring, and since they are for a single year, they are not necessarily typical of these seasonso Similar analyses must be performed on summer and fall data to determine the special influences for these seasons, while data for subsequent years will reveal whether the findings for the first winter and spring are typicalo 40