Implications of Martian polar insolation levels on the climatic cycling of volatiles

Abstract

Solar insolation at the poles is the driving force in Mars' seasonal climatic cycle. Mars' obliquity has varied greatly in the geologically recent past and this would have had a profound effect on the past climate. Previous studies have always assumed a spherical planet when calculating insolation. This study uses a geodetic elevation model (GEM) of the elevation data from the Mars Orbiter Laser Altimeter, to provide accurate insolation calculations. This method takes into account the long and shortwavelength topography, the planetary curvature, and the planetary flattening. This paper outlines the design and implementation of a GEM, and presents insolation calculations for Mar's north polar cap for obliquities of 150, 250 and 450. This study found that the elevation of the northern ice cap above the surroundings results in the ice cap having more days of sunlight than previously thought.