Speaker: John Largier (UC-Davis)
Title: Coastal Circulation Patterns in Upwelling Regions Revealed by HF-Radar
High-frequency radar systems have been deployed for over 20 years in Monterey Bay, and for over a decade across much of California. These data on surface currents have provided new insights to patterns and processes in wind-driven coastal upwelling regions and HF Radar (HFR) has become a key component of coastal ocean monitoring globally. As with the advent of satellite SST data a few decades ago, the advent of spatially dense HFR data on surface currents has revealed the complex patterns of flow, including mesoscale and sub-mesoscale eddies, flow-topography interactions, and plume patterns. Specifically in bays, these data have allowed resolution of circulation patterns and also pseudo-lagrangian estimates of residence times. At the same time, the high sample rate can resolve tidal and diurnal variability in addition to synoptic variability. We have learned that poleward flows in eastern-boundary upwelling are more common than generally appreciated. Distinct spatial patterns in alongshore flows are found in the upwelling and relaxation cycles observed off California, with important implications for the fate of both biogenic and toxigenic material. Specifically, with over a decade of data, typical transport patterns are emerging with important implications for plankton in general and larval dispersal in particular. HFR data are shedding new light on interannual variability in these coastal wind-driven upwelling environments.