Mesoscale Spectra of Mars’s Atmosphere Derived from MGS TES Infrared Radiances

Abstract

Wavenumber spectra of the atmospheric potential energy of Mars at mesoscales (wavelengths of 64?957 km) were obtained as a function of latitude, season, and Martian year using infrared radiance data obtained by the Thermal Emission Spectrometer (TES) onboard the Mars Global Surveyor (MGS) spacecraft. Spectral slopes tend to be flatter at smaller scales, and the slopes are usually flatter than ?1 near small-scale ends. Near large-scale ends, the spectra sometimes show prominent steepening with slopes from ?2 to ?3. The power peaks in the high latitudes in winter and equinoxes, suggesting that eddies are generated preferentially in baroclinic zones. The seasonal variation at each latitude band, on the other hand, tends to be obscured by large interannual variability. An enhancement in the power was observed around the storm tracks in the Southern Hemisphere. Spectra of the terrestrial stratosphere were also obtained with a similar method from data taken by the Aura satellite and compared to the results for Mars.