Evolution of coupled tropopause polar vortices and arctic cyclones prior to very rapid sea ice loss events

Abstract:

The observed, amplified trend in Arctic warming is both well understood theoretically and reproduced in global climate models. However, those same climate models consistently underestimate the observed trend in Arctic sea ice extent (SIE) decline and fail to reproduce observed characteristics in Arctic cyclones. These disparities suggest that a deeper understanding the coupled interactions between the atmosphere, ocean, and sea ice could improve both climate modeling and weather scale forecasting. Very rapid sea ice loss events (VRILEs) have been observed in conjunction with strong cyclones, such as the sea ice loss associated withe the “Great Arctic Cyclone” in August 2012. Additionally, composite means of the atmospheric conditions during a VRILE indicate the presence of a tropopause polar vortex (TPV) coupled with a surface cyclone. Those same composite means suggest there may be seasonal differences between how those systems evolve in the five days prior to the VRILE. Here, we investigate the evolution of the coupled TPV and surface cyclone through case studies of winter and summer VRILEs. We hypothesize that for summer the (JJA) VRILE, the surface cyclone will be strongest the day the VRILE occurs and strongest one to two days before the VRILE for winter VRILEs.