Open AccessAtmospheric and surface retrievals in the Mars polar regions from the Thermal Emission Spectrometer measurements
Author(s) -
Eluszkiewicz Janusz,
Moncet JeanLuc,
Shephard Mark W.,
CadyPereira Karen,
Connor Thomas,
Uymin Gennady
Publication year - 2008
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2008je003120
Subject(s) - radiance , emissivity , mars exploration program , spectral line , atmospheric sciences , polar , atmosphere of mars , environmental science , opacity , spectrometer , remote sensing , physics , martian , geology , optics , astronomy
Retrievals of atmospheric temperatures, surface emissivities, and dust opacities in the Mars polar regions from the Thermal Emission Spectrometer (TES) spectra are presented. The retrievals correspond to two types of spectra, characterized by small and large band depths BD 25 in the 25‐ μ m band of solid CO 2 . These two types of spectra have previously been identified with locations covered by slab ice and fluffy CO 2 frost, respectively. Above the first atmospheric scale height, there is a correlation between the degree of saturation in the retrieved atmospheric temperatures and the two types of surface, with the high BD 25 spectra (“cold spots”) showing larger supersaturations around 1 mbar. This supports the hypothesis that cold spots correspond to locations with potential or actual atmospheric precipitation. Furthermore, the retrieved temperature profiles exhitbit a warming above 1 mbar (15 km), which appears real even when the limited number of independent pieces of information from the measurement (∼3) and coarse vertical resolution of the TES instrument above 15 km are considered. The spectral shape of the retrieved surface emissivities in the cold spot locations is consistent with modeling results attributing high BD 25 to porosity. For the low BD 25 spectra, the retrieved emissivities are spectrally flat but significantly less than unity (0.8–0.9). The cause of these spectrally uniform deviations from blackbody behavior (which are not supported by modeling) remains to be investigated, with a noticeable reduction in the deviation from the blackbody behavior achieved through a zero‐radiance‐level correction to the TES spectra available from the Planetary Data System.