A1137
Title: Scale interactions in the ocean: Designing and analyzing stochastic turbulence closures in complex ocean models
Authors: Stephan Juricke - GEOMAR Helmholtz Centre for Ocean Research Kiel and Constructor University Bremen (Germany) [presenting]
Abstract: Ocean turbulence encompasses complex dynamics, ranging from micro- to planetary scales. Kinetic and potential energy are continuously converted and transferred in time and space. Explicitly modelling these chaotic interactions in global numerical ocean simulations is not feasible due to limited computational resources. One has to resort to limited grid resolution for numerical discretizations, ultimately neglecting small-scale processes that are crucial for correctly capturing the climate system's energy cycle. To still mimic underlying physical interactions, one applies so-called turbulence parameterizations that try to capture some of the statistical properties of unresolved small-scale processes relevant to the resolved, large-scale flow. Several deterministic and stochastic parameterization schemes are presented for so-called oceanic mesoscale turbulence, which is driven by physical instabilities on scales between 1-100km. The schemes are designed to inject energy that has been excessively dissipated in the simulation due to a misrepresentation of relevant energy transfers. Statistical scale analysis is used better to understand energy transfers with and without the parameterizations. Higher resolution simulations where mesoscale instabilities are largely resolved are used to constrain better and improve turbulence closures and their statistical properties. These new developments improve representations of oceanic flow, reducing systematic model biases.
