Sea Surface Temperature and Heat Budget Variability in ECCO2

Oceanic mixed layer heat budgets are crucial for climate modeling efforts because they govern the evolution of sea surface temperatures (SST), the most important oceanic parameter driving atmospheric circulation. Mixed layer heat budget variability is controlled by surface heat fluxes, entrainment, advection, and diffusion. The respective role of these processes varies as a function of region, spatial scale, and frequency. We present results from an analysis of mixed layer heat budgets in a 1992-2007 ECCO2 ocean state estimate. We quantify the various contributions to changes in mixed layer temperature and their associated errors for three oceanic regions in the North Pacific Ocean: the subtropical gyre, an upwelling region off the US West Coast, and a dynamically active area in the Kuroshio region. This regionalization allows for a simplification of the heat budget and the identification of various regimes and frequency/wavenumber bands that are dominated by one or two of the heat budget terms. An integral part of this investigation is the mixed layer heat budget error analysis that allows us to work towards improving the representation of mixed layer processes in ocean models.