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

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.

Automated summary

Latitude and topography influence shadow casting, affecting the stability of water, ice, or snow on the landscape. In a Mars climate model, incorporating a shadow scheme and understanding its interaction with relevant variables is crucial. This study added a shadow scheme to a Mars model and investigated its impact on surface temperature and the presence of surface water ice in the Lyot crater area. The results showed that simulating shadows increased the predicted surface ice amount by up to 83%, with the greatest differences observed in shadowed regions.