Sea Level across North Pacific’s Wide Warm Surface Current

Abstract

Sea level across the wide warm northeastward current off California is calculated from hydrographic data along 35N using the hydrostatic balance and the assumption that the warm mixed layer water floats on the colder stratified water underneath. It is found that the sea level is higher above the warm water by a maximum of 7 cm in the middle of the flow. However, the mean east/west slope of the sea surface is deduced to be too small to balance the Coriolis force on the northward current. Therefore, geostrophy, as it is usually understood, is not operating strictly within the surface layer itself.