High-resolution ocean modelling of the South Georgia and South Orkney Islands regions

The marine ecosystem associated with the ocean shelves around South Georgia and the South Orkney Islands is highly productive, with a history of commercial exploitation. Many of the key oceanographic and ecological processes that determine the structure and functioning of this ecosystem operate over small scales of <10 km. Historically, these fine spatial scales have been poorly represented in numerical models. Here we describe the development of two regional ocean models that will be used to examine the detailed oceanography of the South Georgia and South Orkney Islands shelves and surrounding regions. 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, a seasonal glacial melt cycle, and with sea ice processes incorporated using LIM3.  The models will be used to generate a ~20 year time series of oceanographic flows and water mass properties, which will provide a numerical basis for detailed examination of the controls on the distribution of krill and fish around the islands, their interactions with predators and availability to fisheries. Such detailed analyses will help inform WG-EMM activities aimed at developing spatial and feedback management procedures.