JpGU-AGU Joint Meeting 2020

Presentation information

[E] Oral

P (Space and Planetary Sciences ) » P-PS Planetary Sciences

[P-PS08] Mars and Mars system: results from a broad spectrum of Mars studies and aspects for future missions

convener:Hideaki Miyamoto(University of Tokyo), Tomohiro Usui(Japan Aerospace Exploration Agency), Yuki Harada(Kyoto University), Sushil K Atreya(University of Michigan Ann Arbor)

[PPS08-03] A warm layer in the nightside mesosphere of Mars

*Hiromu Nakagawa1, Sonal K Jain2, Nicholas M Schneider2, Franck Montmessin3, Roger V Yelle4, Fayu Jiang4, Loic Verdier3, Takeshi Kuroda1, Nao Yoshida1, Hitoshi Fujiwara5, Takeshi Imamura6, Kaori Terada1, Naoki Terada1, Kanako Seki7, Hannes Groller4, Justin I Deighan2 (1.Planetary Atmosphere Physics Laboratory, Department of Geophysics, Graduate School of Science, Tohoku University, 2.Laboratory for Atmospheric and Space Physics, University of Colorado, 3.Laboratoire Atmosphères, Milieux, Observations Spatiales, 4.Lunar and Planetary Laboratory, University of Arizona, 5.Faculty of Science and Technology, Seikei University, 6.Graduate School of Frontier Sciences, The University of Toky, 7.Graduate School of Science, The University of Tokyo)

We report a new set of stellar occultation measurements for nightside temperature profiles made by the MAVEN/IUVS that provide evidence for a recurring layer of warm air between 70 - 90 km altitudes in the nightside mesosphere of Mars during Ls = 0º - 180º in Martian Year 33-34. The nightside profiles reveal a recurring peak of atmospheric temperature around 80 km over the equator to the middle latitudes in the northern hemisphere. The predictions of the Mars Climate Database have a warm layer with much smaller amplitudes. The observed peak amplitudes are larger than those predicted by the model by up to 90 K. Wavenumber-3 structures are seen in the warm layer that are potentially signatures of thermal tides or stationary planetary waves, with amplitudes two-times larger than predicted.