Persistent impact of winter atmospheric circulation anomalies on Arctic sea ice

Abstract

According to previous studies, the Arctic Oscillation (AO) in winter has an impact on the evolution of sea ice conditions from winter until the following September. This study explores and compares the sea ice responses to two climatic modes of variability in the winter, the positive phase of the AO and the negative phase of the Arctic Dipole (AD) patterns. This study for the first time verifies that the AD-induced sea ice thickness change is comparable in magnitude to the AO-induced change by the end of the melting season. It proves that the negative AD in winter has a persistent impact on sea ice thickness comparable to the AO has. Furthermore, the AO and AD in the winter impact sea ice conditions in different ways. The AO cannot decrease sea ice thickness until the melting season. Most decreases in sea ice thickness are found over the Beaufort and Chukchi Seas starting in May. On the other hand, the negative AD mostly inhibits sea ice growth during the growing season thermodynamically over the Atlantic sector of the Arctic Ocean. The ensemble means of 22 CMIP6 models can reasonably catch the response of sea ice thickness change to the AO and AD in spatial distribution and temporal evolution. The CMIP6 model ensemble is better at reproducing the AD-induced response of sea ice than the AO-induced response, while the spread of results from individual models is extensive.

Keywords

• sea ice
• atmospheric circulation
• Arctic oscillation
• Arctic Dipole