INTERANNUAL VARIATIONS IN ANTARCTIC PRECIPITATION RELATED TO EL-NINO SOUTHERN OSCILLATION

The accurate estimation of Antarctic precipitation variability is an e ssential component in understanding global sea level fluctuations; dir ect measurement techniques, however, are replete with practical diffic ulties. In this study, net precipitation (precipitation minus sublimat ion) for the Antarctic continent is computed for 1980-1994 using opera tional numerical analyses obtained from the ECMWF (European Centre for Medium-Range Weather Forecasts). The resulting estimations reveal a s trong interannual variability for the Antarctic continent, implying a +/-1.2 - 1.5 mm yr(-1) maximum range in the Antarctic eustatic change contribution. In particular, variability for the South Pacific sector (120 degrees W-180 degrees W) is shown to be correlated with the El Ni no-Southern Oscillation (ENSO) phenomenon for 1980-1990. The relation becomes anticorrelated after 1990, associated with a strong East Antar ctic ridging pattern that coincides with the start of the prolonged se ries of warm events of the early 1990s. This result is relevant to oth er studies relating ENSO variability to high southern latitudes, and a more elaborate picture of this teleconnection pattern is presented. C omparisons of sea level pressure values using available ship observati ons show good agreement and offer a confirmation of the analyses in th is data-sparse region. Additionally, a comparison of results with valu es obtained from the precipitation fields of the NCEP/NCAR (NCEP: Nati onal Centers for Environmental Prediction; NCAR: National Center for A tmospheric Research) reanalysis project are discussed.