Sea surface temerature anomalies near South Georgia: relationships with the South Atlantic and the Pacific El Niño regions

The sea surface temperature dataset of Reynolds and Smith (1994) was used to describe variability around South Georgia. High levels of autocorrelation were evident in the sea surface temperature anomalies, with periodicity evident at a lag period of 4 years. To the north of the island significant autocorrelation was also evident at a lag period of 1 year; though this was restricted to an area that approximately encompassed the Georgia Basin. Crosscorrelation analyses with indices describing the El Niñio areas of the Pacific indicated that temperature fluctuations at South Georgia reflected temperature fluctuations in the Pacific. This link was separated temporally with the Pacific leading South Georgia by almost 3 years, and with the West Pacific showing the strongest correlations. These global teleconnections however, did not completely explain the variability around South Georgia as temperature anomalies also reflected the variability in the Georgia Basin. The high levels of intra annual variability at South Georgia were examined by means of Principal Component Analysis which indicated that seasonal differences between winter and summer were important. These arguments are developed to suggest that temporal variability in the onset of summer warming is potentially of great importance to the functioning of the ecosystem.