A 15-year West Antarctic climatology from six automatic weather station temperature and pressure records

Apart from a small number of mostly coastal stations with human observers, automatic weather stations (AWS) are the dominant source of direct measurements of near-surface climate parameters on the West Antarctic ice sheet. To help alleviate the shortage of surface meteorological data in Antarctica and to better exploit this invaluable data resource, we have used artificial neural network (ANN)-based techniques to extend and fill data gaps in selected AWS records. Climatological analyses of the complete 15-year temperature and pressure records (1979-1993) are reported here for six West Antarctic AWS sites (Siple Station, Byrd, Lettau, Marilyn, Elaine, and Ferrell) spanning ∼90° of longitude. Three sites (Siple, Lettau, and Marilyn) show significant warming trends during the austral summer season (December-February). Warm anomalies of 2°-5°C appeared at all sites during 1980 (winter) and 1989 (winter-spring) with a cold anomaly of up to 3°C during fall 1982. Average intersite seasonal correlation comparisons are highest during fall and winter and lowest in summer; Byrd correlates with no other sites in summer. All sites have short, sharp temperature transitions during the fall and spring seasons and a relatively stable winter season with occasional early to midwinter warmings. Typical winter season conditions are present for up to 5-6 months of the year. An exception occurs at Byrd during 1988 and 1989, when climatologically normal winter conditions did not appear to become fully established. Mean monthly temperatures during this unusual period were 5°-10°C above normal.