Relationships between fast ice and local meteorological conditions at Davis Station, East Antarctica: A case study

Davis Station (77° 58'E, 68° 35'S) is situated along the eastern rim of Prydz Bay on the edge of the Vestfold Hills. Due to its remoteness from the glaciated plateau or nearby glaciers, katabatic winds are generally absent at Davis. Instead wind and air temperature at Davis are largely determined by the cyclonic activity associated with the low-pressure trough, a signature of the marine circulation regime. Meteorological surface and radiosonde data have been collected since the inauguration of the station in 1957, except for January 1965 to February 1969 when the station was closed. Direct measurements of the fast ice near Davis have been carried out intermittently since 1957. Satellite-derived information on the position of the fast-ice extent is available from 1974 onwards. In this study the dominant meteorological regime and long-term variability are investigated. The analysis of time series of various sea-ice and meteorological parameters reveals significant interannual variability, e.g., in maximum annual ice thickness or length of the annual fast-ice season. In recent years a trends towards breakout of fast ice during mid-season has been observed. While this is decreasing the annual maximum ice thickness, the net volume of fast ice produced increases. By combining the meteorological records, with the in situ and remotely sensed sea-ice observations the interactions between fast-ice and meteorological conditions are studied. Dependencies, such as the seasonal movement of the fast-ice edge due to atmospheric forcing, are investigated in the context of climatic interactions (e.g., the zonal shift of the polar trough or changes in the local cyclogenis).