Mountain uplift and surface temperature changes

Abstract

Mountain uplift significantly affects both sea surface temperature (SST) and land surface temperature. This was studied using a coupled atmosphere/mixed layer ocean model with and without mountains. The global mean SST dropped 1.4°C with mountain uplift, mainly due to increased lower tropospheric clouds in the subtropical eastern Pacific. Increased clouds hinder solar radiation into the ocean and lower SST. The increased frequency of stratus incidence is related to subtropical anticyclones intensified by a strong temperature contrast between the continent and ocean in mountainous regions. Land surface temperature drops due to the lapse-rate effect. When this effect is eliminated, the continental interior does not become as cool with mountain uplift because clouds become fewer and the surface drier due to decreased moisture transport. Southern Asia becomes cooler because monsoon-induced precipitation wets the ground and increases clouds. Our result showed greater northern high latitude temperature changes than the previous study, indicating the importance of cloud-related feedback in paleoclimate modeling.