Computationally Efficient Ways to form Approximately Neutral Surfaces

Trevor J McDougall1, Geoff Stanley1,2, Casimir de Lavergne3 and Paul M Barker2, (1)University of New South Wales, Sydney, NSW, Australia, (2)University of New South Wales, School of Mathematics and Statistics, Sydney, NSW, Australia, (3)LOCEAN Laboratory, Sorbonne Université-CNRS-IRD-MNHN, Paris, France
Abstract:
Mesoscale eddies mix ocean properties along locally neutral directions, but these neutral tangent planes do not form a well-defined surface. While well-defined surfaces cannot be exactly neutral, the non-neutral errors can be made to be small. Here we describe two different methods for forming these approximately neutral surfaces, emphasising the computational efficiency of the methods. One method uses a relaxation procedure that is local in character. This method is suitable to be used in forward ocean models that have a layered coordinate (such as MOM6).