Bifurcated flow from an upwelling center: a cold water source for Monterey Bay

AVHRR and CTD data from the Monterey Bay region during spring-summer 1989 show two basic hydrographic states, upwelling and relaxation. These occur in response to local wind forcing and are modified by interaction with a California Current meander. Upwelling at Pt An˜o Nuevo, north of Monterey Bay, is identified as the source of cold, salty near-surface water frequently seen in the Bay. No evidence is found in any available data to support the commonly held belief that the Monterey Submarine Canyon is responsible for the introduction of upwelled water to the Bay's euphotic zone. During wind relaxations, upwelling ceases and a persistent California Current meander translates shoreward. Data support the idea that upwelling centers are associated with coastal headlands. The flow of upwelled water from these centers is bifurcated, with one tongue trending offshore and one equatorward. We propose a conceptual model to explain this pattern of flow and its impact on the California Current.