Atmospheric Response to Anomalous Arctic Sea Ice Loss in CMIP5 Models

Arctic sea ice loss has been implicated by numerous studies as a potential driver of remote (i.e. outside the Arctic) atmospheric changes. The atmospheric response to sea ice changes have been extensively studied in atmospheric model simulations with prescribed sea ice loss. However, such an approach fails to capture feedbacks with the ocean. Here we examine output from coupled climate simulations in the CMIP5 archive. We compare months where anomalous sea ice loss and gain are simulated in pre-industrial control and climate change projections of the CMIP5 models, and analyze the dynamical and thermodynamic properties in the months surrounding these events. These preliminary findings show a fairly robust atmospheric response when comparing months following anomalous sea ice loss to those following anomalous sea ice gain. Significant polar cap potential vorticity (PV) differences are found in the troposphere and stratosphere during the months surrounding anomalous sea ice loss when compared with to those surrounding anomalous sea ice gain. The near-surface atmospheric difference (loss minus gain) is mainly characterized by warm, cyclonic PV anomalies before and concurrent with anomalous sea ice loss. The mid-tropospheric difference shows anticyclonic PV anomalies between one and two months following anomalous sea ice loss compared to sea ice gain. In the upper troposphere and lower stratosphere, the signal only appears in winter and is anomalously cyclonic and warm, following the event by one to two months.