The Formation of Marine Fog and the Development of Fog-Stratus Systems along the California Coast

Abstract

This paper summarizes the results of seven field expeditions aboard the Naval Postgraduate School's R/V Acania, designed specifically to study the formation of marine fog along the California coast. On the basis of observations and analyses, physical models have been formulated for the formation and persistence of at least four different types of marine fog which occur off the West Coast: 1) fog triggered by instability and mixing over warm water patches; 2) fog developed as a result of lowering (thickening) stratus clouds; 3) fog associated with low-level mesoscale convergence; and 4) coastal radiation fog advected to sea via nocturnal land breezes. In addition, it has been found that the triggering of embryonic fogs and further downwind development produces a synoptic-scale fog-stratus system and is responsible for redevelopment of the unstable marine boundary layer after Santa Ana events.