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Observed Wind and SST Variability off the California Coast During Summertime High Wind Events
  • Weiguang Wu,
  • Ana Beatriz Villas Boas,
  • Sarah T. Gille
Weiguang Wu
Massachusetts Institute of Technology

Corresponding Author:[email protected]

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Ana Beatriz Villas Boas
Scripps Institution of Oceanography
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Sarah T. Gille
University of California, San Diego
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Abstract

Sea surface winds off the California coast are characterized by high wind events that occur in spring and summer. In June, a well-defined wind event region is formed off the five major capes, extending ~300km offshore. In the present work, a satellite wind product is used to study the spatial variability of these wind events. High-speed and long-duration events primarily occur off Cape Mendocino, whereas low-speed and short-duration events are more uniformly distributed over the wind event region. Coastal buoy observations show an anti-correlation between wind speed and sea surface temperature (SST) during wind events: a decrease in wind speed accompanies an increase in SST before the start of events, and an increase in wind speed accompanies a decrease in SST after the start of events. Different SST cooling patterns are observed within different categories of wind events: (1) High-speed events lead to more SST cooling compared to low-speed events. (2) Long-duration events lead to longer SST cooling times compared to short-duration events. SST cooling is observed both at nearshore buoy locations and at locations far from the coast. The magnitude of cooling is about 1°C nearshore and 0.3°C offshore. A case study of upper-ocean responses from mooring observations suggests that a combination of enhanced wind-driven mixing and Ekman pumping processes may explain SST cooling nearshore during wind events.