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  • Mars Thermospheric Temperature and Density Distributions: M-GITM Simulated Datasets for Comparison to MAVEN/NGIMS Measurements

    work
    Creator:
    Bougher, Stephen W. and Roeten, Kali J.
    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 derived temperatures and O plus CO2 densities are used to characterize the upper atmosphere dayside thermal and density structure. Presently, more than 6 years of Neutral Gas and Ion Mass Spectrometer (NGIMS) measurements of neutral densities have been obtained by the MAVEN team (e.g. Mahaffy et al. 2015; Bougher et al 2015; Elrod et al., 2017; 2021; Stone et al. 2018; Gupta et al., 2021). Measured neutral density 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 density and temperature distributions and how the atmosphere behaves as a whole system. Three dimensional M-GITM simulations for extreme Mars seasonal and solar cycle conditions were conducted for detailed comparisons with NGIMS derived temperatures and O/CO2 ratio distributions (Bougher et al. 2022). Extracted model densities and temperatures along the MAVEN inbound trajectory of each orbit path (between ~300 km and periapsis) are provided in this Deep Blue Data archive. Corresponding M-GITM heat balance terms are also provided in vertical 1-D tabulated formats. README files are included for each suite of 1-D "flythru" tables, 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.
    Keyword:
    Mars, NASA MAVEN Mission, NGIMS instrument , and M-GITM numerical simulations
    Citation to related publication:
    Bougher, S. W., Benna, M., Elrod, M., Roeten, K., & Thiemann, E. (2023). MAVEN/NGIMS dayside exospheric temperatures over solar cycle and seasons: Role of dayside thermal balances in regulating temperatures. Journal of Geophysical Research: Planets, 128, e2022JE007475.  https://doi.org/10.1029/2022JE007475
    Discipline:
    Science