Effects of sea ice change on the Arctic climate: insights from experiments with a polar atmospheric regional climate model

Abstract

To get insights into the effects of sea ice change on the Arctic climate, a polar atmospheric regional climate model was used to perform two groups of numerical experiments with prescribed sea ice cover of typical mild and severe sea ice. In experiments within the same group, the lateral boundary conditions and initial values were kept the same. The prescribed sea ice concentration (SIC) and other fields for the lower boundary conditions were changed every six hours. 10-year integration was completed, and monthly mean results were saved for analysis in each experiment. It is shown that the changes in annual mean surface air temperature have close connections with that in SIC, and the maximum change of temperature surpasses 15 K. The effects of SIC changes on 850 hPa air temperature is also evident, with more significant changes in the group with reduced sea ice. The higher the height, the weaker the response in air temperature to SIC change. The annual mean SIC change creates the pattern of differences in annual mean sea level pressure. The degree of significance in pressure change is modulated by atmospheric stratification stability. In response to reduction/increase of sea ice, the intensity of polar vortex weakens/strengthens. HIGHLIGHTS The magnitude and extent of the Arctic climate change attributed to sea ice have been studied with a regional Arctic atmospheric model.; Different from previous studies, the numerical experiments were conducted in pair scenarios. In this way, the robustness of response signals can be censored.; Our results show that the consistent signals of atmospheric response to sea ice change can reach up to 500 hPa at least.;

Keywords

• arctic climate
• numerical experiment
• regional climate model
• sea ice