Asymmetries in the Martian Polar Seasonal Caps

• Main Author: Gary Bicas, Carlos E
• Format: Text
• Language: unknown
• Published: CU Scholar 2019
• Subjects: Mars; CO2 snow; albedo; emissivity; dust; seasonal asymmetry; Atmospheric Sciences; Climate; Geomorphology; Other Astrophysics and Astronomy; Physical Processes; The Sun and the Solar System; South Pole; South pole
• Online Access: https://scholar.colorado.edu/honr_theses/1961; https://scholar.colorado.edu/cgi/viewcontent.cgi?article=3062&context=honr_theses

The existence of the residual Carbon Dioxide (CO2) cap near the south pole of Mars may be enabled at least in part by its higher albedo than seasonal CO2 deposits in northern polar region. Snowfall may increase summertime albedo, at the same time it lowers the infrared emissivity of the surface. Direct observations of the emissivities and albedos of the poles can help to understand the possible effects of seasonal snowfall on the polar caps and would describe the possible nature of the polar and atmospheric energy balance. We used Mars Climate Sounder (MCS) data from NASA’s Mars Reconnaissance Orbiter (MRO) to constrain the albedo and emissivity of the seasonal CO2 deposits in both hemispheres at latitudes greater than 60° to investigate whether snowfall may be responsible for the higher albedo of the south polar cap. We produced polar maps for Mars Years 29-33 for emissivity and albedo and contrasted them. We found that snowfall amount is strongly correlated with springtime albedo within the south polar region, and moderately correlated in the north polar region. The highest albedo location on the planet is the south polar residual cap. The northern seasonal cap shows significantly greater snowfall amounts than the south, yet lower albedo. Therefore, the amount of snowfall is not likely to be the primary factor controlling the hemispheric dichotomy of seasonal cap albedo on Mars. Our results suggest that the incorporation of dust is responsible for the lower albedo and reduced stability of Mars’ north polar seasonal CO2 deposits.