P087-05
Thermospheric Temperature Responses during the 2018 PEDE Event as Observed by the MAVEN IUVS Instrument: Implications for Changing Dynamics using Mars GITM Simulations
Wednesday, 16 December 2020: 19:27
Virtual
Stephen W Bougher1, Sonal Jain2, Kali Roeten3, James Richard Murphy4, David J Pawlowski5, Erdal Yiğit6, Justin Deighan2 and Nicholas McCord Schneider7, (1)University of Michigan Ann Arbor, Climate and Space Sciences and Engineering Department, Ann Arbor, MI, United States, (2)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (3)Climate and Space Sciences and Engineering Department, Ann Arbor, MI, United States, (4)New Mexico State University Main Campus, Astronomy, Las Cruces, NM, United States, (5)Eastern Michigan University, Ypsilanti, MI, United States, (6)George Mason University Fairfax, Department of Physics and Astronomy, Fairfax, VA, United States, (7)Univ Colorado, Boulder, CO, United States
Abstract:
The Planet Encircling Dust Event (PEDE-2018) started around 1 June 2018 as viewed in context imaging from MRO/MARCI (Mars Reconnaissance Orbiter/Mars Context Imager), peaked around 7-10 July, and persisted through mid-October 2018. The growth of the dust storm witnessed the horizontal redistribution of dust around the planet (lofting dust up to ~60-70 km), resulting in substantial warming of middle atmosphere temperatures (~25-80 km) as observed by the MRO/MCS (Mars Climate Sounder) instrument. Corresponding upper atmosphere (~150-220 km) responses by neutral densities, temperatures, and winds were measured by the MAVEN NGIMS (Neutral Gas and Ion Mass Spectrometer) and IUVS (Imaging Ultraviolet Spectrograph) instruments during this PEDE storm. For the latter, thermospheric temperatures were extracted from limb profiles of dayglow (CO
2+ UVD) emissions obtained near the dawn (LT ~ 8) and evening (LT ~ 17) terminators (Jain et al., 2019). The time evolution of temperatures at 170 km was monitored through the pre-storm, onset and peak phases of the PEDE event (Ls ~ 180 to 208) at mostly Southern hemisphere latitudes (10N-70S). The underlying thermospheric circulation must have changed substantially during this PEDE event to yield these measured temperatures.
To test this hypothesis, corresponding Mars Global Ionosphere-Thermosphere Model (M-GITM) (Bougher et al., 2015) simulations are conducted and outputs compared to these IUVS temperatures. M-GITM model simulations are driven by time-evolving (daily) solar EUV-UV fluxes (measured by the MAVEN/EUVM instrument) plus time-evolving (daily) dust opacities (measured by the MRO/MCS instrument) during the onset and peak phases of the PEDE storm. In addition, a spectral nonlinear whole atmosphere gravity wave parameterization scheme (Yiğit et al., 2008) has been newly incorporated into M-GITM, and its impact on thermospheric temperatures during this PEDE is investigated. These upgraded M-GITM simulations now demonstrate the changing role of the circulation in impacting thermospheric temperatures during the early to peak phases of this PEDE-2018 event.
