Mapping the U.S. West Coast surface circulation: A multiyear analysis of high-frequency radar observations

Abstract

signals with phase speeds of O(10) and O(100 to 300) km day −1 and time scales of 2 to 3 weeks. The signals with slow phase speed are only observed in southern California. It is hypothesized that they are scattered and reflected by shoreline curvature and bathymetry change and do not penetrate north of Point Conception. The seasonal transition of alongshore surfacecirculationforcedbyupwelling‐favorablewindsandtheirrelaxationiscapturedinfine detail.Submesoscaleeddies,identifiedusingflowgeometry,haveRossbynumbersof0.1to3, diameters in the range of 10 to 60 km, and persistence for 2 to 12 days. The HFR surface currents resolve coastal surface ocean variability continuously across scales from