Impact of Clouds on Surface Radiative Fluxes and Snowmelt in the Arctic and Subarctic

Abstract

A comprehensive atmospheric radiative transfer model combined with the surface energy balance equation is applied to investigate the impact of clouds on surface radiative fluxes and snowmelt in the Arctic and subarctic. Results show that at the surface, the shortwave cloud-radiative forcing is negative, while the longwave forcing is positive and generally much larger than the shortwave forcing. Thus. the all-wave surface cloud-radiative forcing is positive, with clouds warming the lower atmosphere and enhancing snowmelt during the melting period in the Arctic and subarctic. These results agree with and explain observations and measurements over the past three decades showing that the onset of snowmelt stubs earlier under cloudy sky conditions than under clear sky conditions in the Arctic. Clouds could change the date of onset of snowmelt by as much as a month, which is of the order of the observed interannual variations in the timing of snowmelt in the Arctic and subarctic. The all-wave cloud rad... Abstract A comprehensive atmospheric radiative transfer model combined with the surface energy balance equation is applied to investigate the impact of clouds on surface radiative fluxes and snowmelt in the Arctic and subarctic. Results show that at the surface, the shortwave cloud-radiative forcing is negative, while the longwave forcing is positive and generally much larger than the shortwave forcing. Thus. the all-wave surface cloud-radiative forcing is positive, with clouds warming the lower atmosphere and enhancing snowmelt during the melting period in the Arctic and subarctic. These results agree with and explain observations and measurements over the past three decades showing that the onset of snowmelt stubs earlier under cloudy sky conditions than under clear sky conditions in the Arctic. Clouds could change the date of onset of snowmelt by as much as a month, which is of the order of the observed interannual variations in the timing of snowmelt in the Arctic and subarctic. The all-wave cloud rad...