Mesoscale oceanic response to wind events off central California in spring 1989: CTD surveys and AVHRR imagery. [Conductivity/temperature/depth surveys; Selected Advanced Very High Resolution Radiometer satellite imaging]

Author
Schwing, F.B.
Husby, D.M.
Garfield, N.
Tracy, D.E.
Date
1991-11-01Metadata
Show full item recordAbstract
Analysis of hydrographic data obtained during juvenile groundfish surveys, in relation to local wind forcing and AVHRR sea-surface temperature imagery, reveals that the oceanic region off central California between Point Reyes and Point Sur in spring 1989 was characterized by complex circulation patterns and considerable temporal and mesoscale variability. The 'spring transition' to upwelling-favorable winds is most clearly evidenced by rapid, large decreases in SST (up to 4-5C) measured at four meteorological buoys. Daily-averaged winds are spatially coherent and oscillate between upwelling-favorable and relaxation conditions at 3-10-day intervals. Persistent upwelling centers near Point Reyes and Point Ano Nuevo were characterized by relatively cool, salty (8-10C, 33.6-34.0 psu) water in the upper 50 m, which is derived from offshore water at depths of 50-100 m. Water-mass analysis reveals that upwelled water is advected equatorward from its source. Some upwelled water is transported into shallow coastal areas and warmed. Alongshelf fronts between relatively warm, low-salinity ([gt]13C, [lt]33.5 psu) offshore water and cool, higher-salinity upwelled water are advected onshore in response to wind relaxation or reversal events: frontal gradients intensify at these times. AVHRR imagery verifies the spatial patterns and complex mesoscale variability of the near-surface patterns observed in the CTD survey data. Eddylike hydrographic features are noted with horizontal scales on the order of the station spacing (10 km). How the complex circulation patterns and intense mesoscale spatial and temporal variability affect the survival and subsequent recruitment of juvenile groundfish is discussed.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.Collections
Related items
Showing items related by title, author, creator and subject.
-
The space-time scales of variability in oceanic thermal structure off the Central California coast
Breaker, Laurence Coates (Monterey, California. Naval Postgraduate School, 1983-12);The space-time scales of variability in ocean thermal structure are examined off the Central California coast. In the active coastal upwelling regime off Pr. Sur, there was an equatorward surface jet 15 to 40 km offshore, ... -
Variations in coastal circulation off Central California, spring-summer, 1993, 1994, 1995
Parker, Heather A. (Monterey, California. Naval Postgraduate School, 1996-12);In situ measurements of hydrographic, wind and Acoustic Doppler Current Profiler (ADCP) data, along with satellite imagery, were collected off central California during the upwelling season of three successive years, 1993, ... -
Subtidal circulation over the upper slope to the west of Monterey Bay, California
Morales, Juan Aguilar. (Monterey, California. Naval Postgraduate School, 2003-09);Moored current meters were used to describe currents over the continental slope off Monterey Bay, California, from March 1998 to March 2003. The water depth at this location was 1800 m and current observations included of ...