ISPOL weather conditions in the context of long-term climate variability in the north-western Weddell Sea

At the transition from austral spring to summer of 2004/2005, the field experiment Ice Station Polarstern (ISPOL) took place in the north-western Weddell Sea to observe physical and biological atmosphere–sea ice–ocean processes. The objective of this paper is to discuss the meteorological conditions during ISPOL in the context of long-term climate variability mainly in the north-western Weddell Sea region. This is done with a comprehensive climatology focusing on the seasonal and interannual variability of atmospheric and cryospheric data from 1979 to 2005. Key meteorological elements and weather patterns derived from NCEP/DOE Reanalysis 2 results and sea-ice data from passive microwave radiometer satellite observations are analyzed in combination with ISPOL in situ measurements. The monthly mean air temperature and the mean sea-level pressure were above the long-term average. The latter showed a very much extended variability and range associated with more frequent northerly to south-easterly winds.