Surface Kinetic Energy Distributions in the Global Oceans From a High-Resolution Numerical Model and Surface Drifter Observations

Abstract : The surface kinetic energy of a 1/48° global ocean simulation and its distribution as a function of frequency and location are compared with the one estimated from 15,329 globally distributed surface drifter observations at hourly resolution. These distributions follow similar patterns with a dominant low-frequency component and well-defined tidal and near-inertial peaks globally. Quantitative differences are identified with deficits of low-frequency energy near the equator (factor 2) and at near-inertial frequencies (factor 3) and an excess of energy at semidiurnal frequencies (factor 4) for the model. Owing to its hourly resolution and its near-global spatial coverage, the array of surface drifters is an invaluable tool to evaluate the realism of tide-resolving high-resolution ocean simulations used in observing system simulation experiments. Sources of bias between model and drifter data are discussed, and associated leads for future work highlighted.