A growing fraction of the World's population lives in coastal regions where activities require information about surface current. On global scales surface current is also an essential variable for weather and climate forecasting, shipping, environmental pollution, and other blue-ocean activities. The Blended Ocean Surface Current (BOSC) is a new daily NOAA Coastwatch-Oceanwatch data-driven surface current product that augments the traditional geostrophic/Ekman momentum equation approach with information from ocean thermodynamics as well as the observations of the motions of surface drifters and sea ice.
Synoptic-scale nearsurface motion is well represented by a linear three-term momentum balance (Coriolis, pressure-gradient, and vertical shear stress) which can be solved for velocity given observations of pressure (from satellite altimetry), surface stress (from atmospheric reanalyses), and a parameterization for vertical momentum diffusion. Where this three-term balance breaks down is on shorter space- and time-scales, and in regions such as the deep tropics or near strong fronts where advection is important. Unfortunately these are the scales and regions that tend to have high human and environmental/climate impact. The BOSC project will provide global daily surface currents at fine 1/6°x1/6° resolution, paying particular attention to high these impact regions. Emphasis is also placed developing reasonable error estimates. Finally, BOSC is designed to complement future satellite swath altimeter and doppler scatterometer data streams. A BOSC β-release is expected in late 2022.
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Credit: James Carton 10/05/2022 |  |