The Combined Influence of ENSO and SAM on the Antarctic Peninsula Climate

The influence of the tropics on the climate of West Antarctica and the Antarctic Peninsula has recently gained considerable attention. In particular, variability in the tropics associated with the El Niño – Southern Oscillation (ENSO) may be related to the regional warming trends across West Antarctica and the Antarctic Peninsula. Previous work has detailed the importance of the combined role of ENSO and the Southern Annular Mode (SAM) on pressure variability over the South Pacific and the Amundsen/Bellingshausen Seas. This research examines the combined role of ENSO and SAM on the Antarctic Peninsula climate, and the large-scale atmospheric response in the Amundsen and Bellingshausen Seas to different ENSO/SAM phase combinations.

Using data from the ERA-Interim atmospheric reanalysis, we find strong relationships between ENSO, SAM, atmospheric pressure, wind, and temperature across West Antarctica and the Antarctic Peninsula. Interestingly, the relationship varies considerably with varying combined phases of ENSO and SAM. Furthermore, the ENSO-SAM relationship and its temporal variability govern how ENSO and SAM separately influence the Antarctic Peninsula climate. For example, a relationship exists between the ENSO-SAM correlation and the ENSO influence on mean sea level pressure, temperature, wind speed, and wind direction across the Antarctic Peninsula. The results suggest that the relationship between ENSO and SAM govern much of the climate variability across the Antarctic Peninsula.