Modeling infrared thermal emissions on Mars during dust storm of MY28: PFS/MEX observation

Syed A. Haider, Masoom P. Jethwa, Takeshi Kuroda, Yasumasa Kasaba, Marco Giuranna.
January, 2016

We have analysed thermal emission spectra obtained from Planetary Fourier Spectrometer (PFS) onboard Mars Express (MEX) for Martian Year (MY) 28 in presence and absence of dust storm at low latitude. A radiative transfer model for dusty atmosphere of Mars is developed to estimate the thermal emission spectra at latitude range 0-10oS, 10-20oS and 20-30oS. These calculations are made at Ls=240o, 280o, 300o, and 320o between wave numbers 250-1400 cm-1. We have also retrieved brightness temperatures from thermal emission spectra by inverting the Planck function. The model reproduces the observed features at wave numbers 600-750 cm-1 and 900-1200 cm-1 due to absorptions by CO2 and dust respectively. In presence of dust storm thermal emission spectra and brightness temperature are reduced by a factor of 2 between wave numbers 900-1200 cm-1. The altitude pro les of dust concentration are also estimated for di erent aerosol particles of sizes 0.2 to 3 m. The best t to the PFS measurements is obtained in presence of aerosol particle of size 0.2 m.

41st COSPAR Scienti c Assembly 2016