Simulating Arctic sea ice variability with a coupled regional atmosphere-ocean-sea ice model

Abstract

A regionally coupled model consisting of the regional atmosphere model REMO and the global ocean model MPI-OM is forced with reanalysis data for the period 1958 to 2001. The coupled domain includes the Arctic Ocean, the Nordic Seas, the northern North Atlantic and Europe. The model simulates marked interannual variability in Arctic sea ice export through Fram Strait and reproduces the large event that lead to the Great Salinity Anomaly in the late 60s/early 70s. Ensemble simulations show large variability between different realisations indicating that a single realisation is not sufficient to analyse the climate response of the model to variations in the boundary conditions. With our experiments it is possible to show that both the large-scale atmospheric circulation and the variability generated inside the model domain contribute to sea ice export events. In one of the ensemble members the sea ice export event in the mid 60s has led to permanent suppression of deep convection in the Labrador Sea up to the end of the experiment in 2001.