The Wave Origins of Longitudinal Structures in ExoMars Trace Gas Orbiter (TGO) Aerobraking Densities

The nature and origins of longitudinal density structures in Mars’ thermosphere between 100 120 km altitude, −30° −75° latitude around winter solstice (Ls = 70–122°), as measured by the accelerometer on ExoMars Trace Gas Orbiter (TGO) Mission, are investigated. methodology consists deducing responsible waves comparing observed longitude versus local time phase progressions with those probable candidate Mars Climate Database (MCD) climatology. wave-1, wave-2, wave-3 interpreted originating mainly from SPW1; (SPW2, S0, DE1); (SPW3, DE2), respectively, where SPWm denotes a stationary planetary wave zonal wavenumber s m, S0 is zonally symmetric semidiurnal tide, DE1(DE2) eastward-propagating diurnal tides −1(−2). All these exist MCD amplitudes large observed, although not wholly narrow height-latitude regime accessed TGO. This disparity TGO amplitude hypothesized to result extreme intrusion polar-region eastward jet into MCD. polar blocks poleward expansion DE1 DE2 beyond latitude, also impacts SPW2, SPW3 that arise situ nonlinear interaction DE2, migrating tide (DW1).