The impact of a shadows scheme on a Mars mesoscale climate model

Abstract

Latitude and topography affect the amount of shadow cast on a landscape, which in turn can influence where water, ice or snow are stable. For martian climate models, whose output sometimes disagrees with observational data, we show that adding the ability to represent shadows generated by topography and understanding how they interact with relevant modelled variables can be important. We included a shadows scheme in a Mars mesoscale climate model and report on the impact that shadows had on surface temperature, and the resultant impact on one variable – surface water ice, and its accumulation or ablation in the study area of Lyot crater. Incorporating a scheme simulating shadows cast by topographical features had a measurable effect, increasing by up to 83% the amount of surface ice that the model predicted would be found in shadowed areas. The largest differences in ice content between simulations with and without shadows were found in those areas with the greatest amount of shadow.