Atmospheric flow patterns associated with low sea-ice cover in the Barents-Kara Seas

Speaker: 
Svetlana Sorokina
Seminar Date: 
1. March 2012 - 12:30 - 13:00
Location: 
Lecture room, Ground Floor, NERSC

This study explores links between low sea-ice cover in the Barents-Kara Seas and accompanying atmospheric anomalies by means of re-analysis data and a general circulation model (GCM) control experiment. In both data sets low sea-ice concentrations are associated with enhanced sea-air heat fluxes and a local warm anomalous low pressure in the lower troposphere. In the re-analysis data the local anomaly was deeper and connected with non-local structures reminiscent of a Rossby wave train. We demonstrate that the different background states in the reanalysis and the GCM may explain the different structures of the flow anomalies tied to the low sea-ice cover. More specifically, the observationally based structure of the atmospheric background state in the Barents-Kara Seas region is less stable and thus more favorable for deep convection due to surface heating than that of the GCM. The potential for zonally asymmetric diabatic heating and thus Rossby wave generation is higher in the observationally based dataset than in the GCM.