Schematic block diagram of generalized circulation. Prevailing winds blow equatorward toward the south with brief periods of relaxation or reversal. Surface waters flow offshore in the Ekman layer, which is weak and a few meters deep nearshore and stronger and about 15 to 30 m deep offshore. Cold, deep waters flow onshore and upwell to the surface often forming a front with warmer surface waters. Nearshore, prevailing currents flow poleward, as indicated by the circle with a dot in middle. Offshore, currents flow equatorward near the surface, as indicated by the circle with a cross in middle, and poleward at depth. Cross-shelf and alongshore transport is regulated by the amount of time larvae spend near the surface and bottom in stratified currents.