Orographic disturbances of surface winds over the shelf waters adjacent to South Georgia

Abstract

This study seeks to quantify the influence of South Georgia's orography on regional surface winds. A typical case study characterized by large-scale westerly winds is analysed using a high-resolution setup (3.3km) of the Weather Research and Forecasting (WRF) regional model. The simulation produces significant fine-scale spatial variability which is in agreement with satellite-derived winds. The model simulation indicates that these orography-driven wind disturbances are responsible for strong wind stress curl and enhanced heat flux over the shelf waters surrounding South Georgia. Such surface forcing is entirely absent from the reanalysis, highlighting the need to use high-resolution forcing in regional ocean model simulations.