Impacts of Sea Ice Mushy Thermodynamics in the Antarctic on the Coupled Earth System

Abstract

AbstractWe analyze two preindustrial experiments from the Community Earth System Model version 2 to characterize the impact of sea ice physics on differences in coastal sea ice production around Antarctica and the resulting impact on the ocean and atmosphere. The experiment in which sea ice is a more realistic “mushy” mixture of solid ice and brine has a substantial increase in coastal sea ice frazil and snow ice production that is accompanied by decreasing bottom ice growth and increasing bottom melt. The more realistic “mushy” physics leads to an increase in water mass formation at denser water classes due primarily to surface ice processes. As a result, the subsurface ocean is denser, saltier, and there is an increase in Antarctic Bottom Water formation of 0.5 Sv. For the atmosphere, “mushy” ice physics leads to decreased turbulent heat flux and low level cloud cover near the Antarctic coast.