A climatological analysis of high‐precipitation events in Dronning Maud Land, Antarctica, and associated large‐scale atmospheric conditions

Abstract

Abstract The link between high precipitation in Dronning Maud Land (DML), Antarctica, and the large‐scale atmospheric circulation is investigated using ERA‐Interim data for 1979–2009. High‐precipitation events are analyzed at Halvfarryggen situated in the coastal region of DML and at Kohnen Station located in its interior. This study further includes a comprehensive comparison of high precipitation in ERA‐Interim with precipitation data from the Antarctic Mesoscale Prediction System (AMPS) and snow accumulation measurements from automatic weather stations (AWSs), with the limitations of such a comparison being discussed. The ERA‐Interim and AMPS precipitation data agree very well. However, the correspondence between high precipitation in ERA‐Interim and high snow accumulation at the AWSs is relatively weak. High‐precipitation events at both Halvfarryggen and Kohnen are typically associated with amplified upper level waves. This large‐scale atmospheric flow pattern is preceded by the downstream development of a Rossby wave train from the eastern South Pacific several days before the precipitation event. At the surface, a cyclone located over the Weddell Sea is the main synoptic ingredient for high precipitation both at Halvfarryggen and at Kohnen. A blocking anticyclone downstream is not a requirement for high precipitation per se, but a larger share of blocking occurrences during the highest‐precipitation days in DML suggests that these blocks strengthen the vertically integrated water vapor transport (IVT) into DML. A strong link between high precipitation and the IVT perpendicular to the local orography suggests that IVT could be used as a “proxy” for high precipitation, in particular over DML's interior.