Concurrent effects of Martian topography on the thermosphere and ionosphere at high northern latitudes

Earth, Planets and Space

Yiding Chen¹  Libo Liu²  Huijun Le²  Ruilong Zhang²  Hui Zhang² 

[1]Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China

[2]Innovation Academy for Earth Science, CAS, 100029, Beijing, China

[3]Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China

[4]College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China

[5]Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China

[6]Innovation Academy for Earth Science, CAS, 100029, Beijing, China

[7]Heilongjiang Mohe Observatory of Geophysics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China

[8]College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China

关键词: Martian ionosphere;    Neutral scale height;    Longitude variation;   

DOI  :  10.1186/s40623-022-01582-w

来源: Springer

【 摘 要 】

Martian topography modulated non-migrating tides play important roles in the upper atmosphere and thus in the ionosphere through their coupling, especially in their longitude variations. In this study, the neutral scale height (Hn) and ionospheric peak electron density (NmM2) and height (hmM2) retrieved from the MGS radio occultation measurements were used to investigate the coupling between the Martian thermosphere and ionosphere under the forcing of topography modulated tides by investigating their concurrent longitude variations. A segment of the measurements with fixed local time was selected to analyze the relationships between the longitude variations of the parameters in detail. Longitude variations of the thermosphere and ionosphere are significant though topographic fluctuations are not very prominent at high northern latitudes. Longitude fluctuations of Hn and NmM2 are nearly in anti-phase and percentage fluctuation amplitudes of Hn are nearly twice as large as those of NmM2, which indicate the non-migrating tide forced coupling between the ionosphere and thermosphere conforms to the Chapman theory, and suggests longitude variation of NmM2 can be used as a quantitative indicator for that of the thermal structure in the lower thermosphere. Longitude variation phases of Hn and hmM2 are also discrepant. That is due to tide vertical propagation since Hn and hmM2 depend on the atmospheric thermal structures at different height levels. The thermosphere and ionosphere show longitude variations due to the topography; however, they are dominated by inconsistent longitude components. This implies discrepant exciting and propagating efficiencies of various topography modulated tides.Graphical Abstract

【 授权许可】

CC BY