Work Description

Title: Mars Thermospheric Helium Distributions: M-GITM Simulated Datasets for Comparison to MAVEN/NGIMS Measurements Open Access Deposited

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Methodology
  • Simulated neutral densities (CO2, CO, N2, O, Ar, O2, N, NO, including helium) and corresponding zonal, meridional and vertical neutral winds of the Mars thermosphere are calculated by the 3-D numerical model called M-GITM (Mars Global Ionosphere-Thermosphere Model), developed at the U. of Michigan. This is a climate model whose domain extends from the surface to ~250 km (Bougher et al., 2015). Neutral plus ion densities, neutral temperatures and winds are calculated on a 3-D grid (latitude, longitude, altitude) for NASA MAVEN spacecraft conditions corresponding to specific instrument measurements made. These 3-D model calculations are time-marching, making use of a finite-difference code which solves the Navier-Stokes equations for temperatures, composition, and winds. Large datacubes are created of M-GITM outputs fields for deposit on this archive
Description
  • The NASA MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft, which is currently in orbit around Mars, has been taking systematic measurements of the densities and deriving temperatures in the upper atmosphere of Mars between about 140 to 240 km above the surface since late 2014. Wind measurement campaigns are also conducted once per month for 5-10 orbits. These densities, temperatures and winds change with time (e.g. solar cycle, season, local time) and location, and sometimes fluctuate quickly. Global dust storm events are also known to significantly impact these density, temperature and wind fields in the Mars thermosphere. For the current project, the inert light species helium is used to trace the circulation patterns and constrain wind magnitudes throughout the Mars thermosphere. Presently, more than 6 years of Neutral Gas and Ion Mass Spectrometer (NGIMS) measurements of helium densities have been obtained by the MAVEN team (e.g. Elrod et al., 2017; 2021; Gupta et al., 2021). Measured helium distributions are compared to simulations from a computer model of the Mars atmosphere called M-GITM (Mars Global Ionosphere-Thermosphere Model), developed at U. of Michigan. Since the global circulation plays a role in the structure, variability, and evolution of the atmosphere, understanding the processes that drive the winds in the upper atmosphere of Mars also provides the needed context for understanding helium distributions and how the atmosphere behaves as a whole system. Three dimensional M-GITM simulations for the Mars four cardinal seasons (Ls = 0, 90, 180, 270, for Mars Year 33) were conducted for detailed comparisons with NGIMS helium and CO2 distributions (Gupta et al. 2021). The M-GITM datacubes used to extract these densities (plus winds) along the trajectory of each orbit path between 140 and 240 km, are provided in this Deep Blue Data archive. README files are also provided for each datacube, detailing the contents of each file. In addition, a general README file is provided that summarizes the inputs and outputs of the M-GITM code simulations for this study. Finally, a basic version of the M-GITM code can be found on Github at https:/github.com/dpawlows/MGITM.
Creator
Depositor
  • bougher@umich.edu
Contact information
Discipline
Funding agency
  • National Aeronautics and Space Administration (NASA)
ORSP grant number
  • PGN F031116
Keyword
Citations to related material
  • Gupta, N., N. V. Rao, S. W. Bougher, and M. K. Elrod, Latitudinal and Seasonal Asymmetries of the Helium Bulge in the Martian Upper Atmosphere J. Geophys. Res., 126, XXXX-XXXX. doi:10.1002/2021JEXXXXXX
Resource type
Last modified
  • 11/19/2022
Published
  • 08/05/2021
Language
DOI
  • https://doi.org/10.7302/36zc-y350
License
To Cite this Work:
Bougher, S. W. (. D. O. M. (2021). Mars Thermospheric Helium Distributions: M-GITM Simulated Datasets for Comparison to MAVEN/NGIMS Measurements [Data set], University of Michigan - Deep Blue Data. https://doi.org/10.7302/36zc-y350

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Files (Count: 9; Size: 141 MB)

Thumbnailthumbnail-column Title Original Upload Last Modified File Size Access Actions
README.MGITM.GENERAL.txt 2021-08-05 2021-08-05 6.3 KB Open Access
README.LS000.150619.DATACUBE.txt 2021-08-04 2021-08-04 1.58 KB Open Access
MY33.LS0.MENCA.150619.UT13.userdetic.dat 2021-08-04 2021-08-04 35.3 MB Open Access
README.LS090.160104.DATACUBE.txt 2021-08-04 2021-08-04 1.58 KB Open Access
MY33.LS90.MENCA.160104.UT21.user...c.dat 2021-08-04 2021-08-04 35.3 MB Open Access
README.LS180.160705.DATACUBE.txt 2021-08-04 2021-08-04 1.58 KB Open Access
MY33.LS180.MENCA.160705.UT18.use...c.dat 2021-08-04 2021-08-04 35.3 MB Open Access
README.LS270.161129.DATACUBE.txt 2021-08-04 2021-08-04 1.58 KB Open Access
MY33.LS270.MENCA.161129.UT17.use...c.dat 2021-08-04 2021-08-04 35.3 MB Open Access

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Date: 04-August-2021
Who: S. W. Bougher
General Details of MGITM datasets for MENCA Team Helium Project

*****************************************************************************************

Description: The NASA MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft, which is currently in orbit around Mars, has been taking systematic measurements of the densities and deriving temperatures in the upper atmosphere of Mars between about 140 to 240 km above the surface since late 2014. Wind measurement campaigns are also conducted once per month for 5-10 orbits. These densities, temperatures and winds change with time (e.g. solar cycle, season, local time) and location, and sometimes fluctuate quickly. Global dust storm events are also known to significantly impact these density, temperature and wind fields in the Mars thermosphere. For the current project, the inert light species helium is used to trace the circulation patterns and constrain wind magnitudes throughout the Mars thermosphere. Presently, more than 6 years of Neutral Gas and Ion Mass Spectrometer (NGIMS) measurements of helium densities have been obtained by the MAVEN team (e.g. Elrod et al., 2017; 2021; Gupta et al., 2021). Measured helium distributions are compared to simulations from a computer model of the Mars atmosphere called M-GITM (Mars Global Ionosphere-Thermosphere Model), developed at U. of Michigan. Since the global circulation plays a role in the structure, variability, and evolution of the atmosphere, understanding the processes that drive the winds in the upper atmosphere of Mars also provides the needed context for understanding helium distributions and how the atmosphere behaves as a whole system. Three dimensional M-GITM simulations for the Mars four cardinal seasons (Ls = 0, 90, 180, 270, for Mars Year 33) were conducted for detailed comparisons with NGIMS helium and CO2 distributions (Gupta et al. 2021). The M-GITM datacubes used to extract these densities (plus winds) along the trajectory of each orbit path between 140 and 240 km, are provided in this Deep Blue Data archive. README files are also provided for each datacube, detailing the contents of each file. In addition, a general README file is provided that summarizes the inputs and outputs of the M-GITM code simulations for this study. Finally, a basic version of the M-GITM code can be found on Github at https:/github.com/dpawlows/MGITM.

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MY33 Cardinal Season Production Simulations (see Gupta et al., 2021; Elrod et al., 2017)
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Interval Date (2015-16) Season (Ls) Narrative
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1 June 19,'15 0.0 MY33 Vernal Equinox
2 Jan 4,'16 90.0 MY33 Aphelion
3 July 5, 16 180.0 MY33 Autumnal Equinox
4 Nov 29,'16 270.0 MY33 Perhelion

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MGITM Results are presented on a regular GEO grid (Longitude-Latitude-Altitude):
-------------------------------------------------------------------------
LON (72 elements) = 2.5 to 357.5 by 5.0 degree interval (fastest index)
LAT (36 elements) = -87.5 to +87.5 by 5.0 degree interval
ALT (62 elements) = 98.75 to 293.75 km by 2.5 km interval (slowest index)

where

LON (2.5 to 180 to 357.5E) corresponds to SLT = 12 to 24 to 12
(We have selected the proper UT for each dataset for this match)

Fields (15):
-- Temperatures : Tn
(neutral)
-- Major neutral densites : [CO2], [O], [N2], [CO], [He], [Ar]
-- Major plasma densities : none here
(dayside only, best in PCE region below 200 km)
-- 3-component neutral winds: Un, Vn, Wn
-- Pressure (total) : P
-- Solar Zenith Angle : SZA

Units = All Temperatures (K), All densities (#/m3), 3-component winds (m/s),
Pressure (pascals), SZA (degrees)

File Nomenclature:
------------------------------
MY33.LSXXX.MENCA.YYMMDD.utXX.userdetic.dat

YY = last 2-digits of year
MM = 2-digit month
DD = 2-digit day of month
XX = Universal Time (on Earth): 2-digit integral hours
MonthYear = MY33 Interval

e.g. MY33.LS270.MENCA.161129.ut17.userdetic.dat
YY = 16
MM = 11
DD = 29
XX = 17

9-Files in the respository for downloading:
-----------------------------------------------------------------------------------
README.MGITM.General.txt

MY33.LS0.MENCA.150619.UT13.userdetic.dat
README.LS000.150619.DATACUBE.txt

MY33.LS90.MENCA.160104.UT21.userdetic.dat
README.LS090.160104.DATACUBE.txt

MY33.LS180.MENCA.160705.UT18.userdetic.dat
README.LS180.160705.DATACUBE.txt

MY33.LS270.MENCA.161129.UT17.userdetic.dat
README.LS270.161129.DATACUBE.txt

FISM-Mars daily averaged solar EUV-UV fluxes (1-195 nm) used based upon MAVEN
Extreme Ultraviolet Monitor (EUVM) instrument: Thiemann et al. (2017).
-------------------------------------------------------------------------------------
Level 3 EUVM daily products used: v14_r00 (all MY33 intervals)

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Specific Key References pertaining to MGITM Simulations plus MAVEN NGIMS and EUVM Datasets:
--------------------------------------------------------------------------------------
Bougher et al. (2015), J. Geophys. Res., 120, 311-342. doi:10.1002/2014JE004715.
Thiemann et al. (2017), J. Geophys. Res., 122, 2748-2767. doi:10.1002/2016JA023512.
Elrod et al. (2017), J. Geophys. Res., 122, 2564-2573. doi:10.1002/2016JA023482.

Gupta, N., N. V. Rao, S. W. Bougher, and M. K. Elrod,
Latitudinal and Seasonal Asymmetries of the Helium Bulge in the Martian Upper Atmosphere
J. Geophys. Res., 126, XXXX-XXXX. doi:10.1002/2021JEYYYYYY.

Citation for this dataset:
-------------------------

Bougher, S. W., (2021) M-GITM Simulatd Helium Distributions during MY33 for Comparison to
MAVEN Neutral Gas and Ion Mass Spectrometer (NGIMS) Measurements: Latitudinal and Seasonal Asymmetries. University of Michigan - Deep Blue Data. https://doi.org/10.7302/36zc-y350

*****************************************************************************************

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