Search

The spatial variability of seasonal mean temperature departures at 26 stations around Antarctica, southern South America, and nearby islands is shown using factor analysis. An opposition in temperature anomalies between mainland stations and those on or near the An opposition in temperature anomalies between mainland stations and those on or near the Antarctic Peninsula is a recurring pattern of spatial variability in all seasons but spring. Other factors indicate that temperature anomalies alternate in sign around the continent and especially near the peninsula. The association between the spatial patterns of temperature variability and features of the atmospheric circulation at middle and higher latitudes of the Southern Hemisphere is also examined. In each season the time series of one factor is significantly associated with temporal variations in the strength of the 500 mb westerlies, measured using height differences across six pairs of middle-latitude and Antarctic stations. In winter and summer the westerlies are linked to the mainland/Peninsula temperature opposition pattern such that when zonal flow is anomalously strong, mainland stations are anomalously cold. In autumn and spring, temperature variability is highly related to meridional flow strength over New Zealand and in the lee of the Andes, and is associated with interannual longitudinal shifts in the positions of the climatological lows near the Antarctic coast. A deep Andes trough is associated with longer-than-usual ice duration at the South Orkneys. Historically, strong troughing and heavy sea-ice conditions in the South Atlantic occurred between 1920 and 1935. [ABSTRACT FROM AUTHOR]