Department of Oceanography, University of Hawaii at Manoa, Honolulu, Hawaii
ABSTRACT Intense diurnal warming of the ocean surface was observed in April 1982 off California, using a combination of mooring, hydrographic and satellite infrared and satellite pigment measurements. The event corresponded to a spatial and temporal minimum of the wind stress. The diurnal surface temperature amplitude exceeded 6.6 C locally despite a 490-nm optical depth of 20 m, suggesting that phytoplankton was not responsible for the shallow heat trapping. Coherent horizontal temperature streaks at least 50 km long and 4 to 8-km wide formed during the subsequent erosion of the shallow warm layers. It is hypothesized that their scale was set by planetary boundary layer circulations.