A Numerical Modeling Study of the Weather in East Antarctica and the Surrounding Southern Ocean

Abstract

The requirement for more detailed and accurate weather forecasts in Antarctica has steadily grown over the past decade, to the point where more sophisticated high-resolution numerical weather prediction (NWP) systems need to be employed to provide the mesoscale prediction services demanded. The following paper discusses the performance of the Antarctic Limited-Area Prediction System (ALAPS) in providing weather forecasting support at high latitudes. Verification results based on traditional statistical techniques, including the S1 skill score and bias and root-mean-square errors, are presented. They suggest that the high-resolution gridpoint model provides no improvement over the global model used for the nesting fields. However, it is argued that the traditional statistical techniques fail to capture the advantages of the high-resolution gridpoint model, and three case studies are presented to highlight the ALAPS model performance characteristics. The first case study is an example of the model performance in forecasting extreme wind events at Casey station (66.279°S, 110.536°E), highlighting the ability of the model to define the flow characteristics of supergeostrophic storm events. The second case study highlights the model performance in oceanic route forecasting over the Southern Ocean, while the third provides an example of the model simulation of the katabatic flow at Mawson (67.601°S, 62.873°E). In each case, the ALAPS model enhanced the forecast guidance available from the global model used to provide the nesting fields and provided high-resolution data with which to explore the dynamics associated with high-latitude weather systems.