Oceanography of the South Georgia and South Orkney Islands regions using high-resolution models

The shelf regions around South Georgia and the South Orkney Islands are highly productive, supporting large colonies of higher predators, and with a history of commercial exploitation. Many of the key oceanographic and ecological processes determining the operation of these marine ecosystems operate over small spatial scales of <10 km. Understanding the drivers of variability in such processes requires the development of high-resolution ocean models. Here we describe the development of regional models for the South Georgia and South Orkney Islands shelves and surrounding regions, and present the results of preliminary analyses. The models are regional applications of NEMO with a ~3 km horizontal resolution, and include key physical processes of relevance to the local ecosystems including tides, atmospheric forcing from reanalysis, glacial melt, and with sea ice processes incorporated using LIM3. The models have been used to generate 20-year hindcast time series of oceanographic flows and water mass properties. This valuable resource is providing the underlying physical environment for detailed examinations of the controls on the distribution of krill and fish around the islands, their interactions with predators and availability to fisheries. Insight from such studies will help inform WG-EMM activities aimed at developing spatial and feedback management procedures.