Abstract

Average summer temperatures over South Georgia have risen by around 1 C since the 1920s, while glaciers have retreated at variable rates. In parallel with these changes, surface westerlies have increased by about 3 m/s. As South Georgia is a mountainous island, with 19 peaks over 2 km, strong downslope winds can develop on the lee side of the island causing dramatic temperature increases as the descending air warms adiabatically — this is known as the föhn effect.

In this talk, I will investigate the extent by which these observed changes are due to the föhn effect by showing preliminary results from a 10-year climatology based on AWS data, and high-resolution simulations using the Weather Research and Forecasting (WRF) model.

A better understanding of these atmospheric processes will provide greater confidence in modelling regional climates in mountainous terrain, as well as producing better predictions concerning South Georgia’s terrestrial and marine environments which support rich yet delicate ecosystems.