The seminal work of Ekman during the early twentieth century showed that wind blowing parallel to the coast and the effects of the Earth’s rotation can produce offshore transport in the surface boundary layer and upwelling of cold, dense water near the coast. This process stimulates high primary productivity by supplying nutrient-rich water to the euphotic zone. Ekman’s theory and many modern studies predict that the upward transport associated with coastal upwelling occurs over a shallow region near shore known as the inner shelf. However, these theories do not account for sharp gradients in velocity and density near the front that separates cold, dense water near shore from the warmer, lighter water farther offshore. Observations, idealized modeling experiments and a new theory are presented to explain how the cross-shore distribution of upwelling changes in different situations. A simple ecosystem model illustrates the potential effects on plankton distributions and primary productivity.
Tom is a physical oceanographer at Moss Landing Marine Labs who studies the dynamics and ecological impacts of circulation in the coastal zone. Tom received his Ph.D. in Oceanography from the University of Washington in 2012, where he studied shelf and slope circulation off the coasts of Washington and British Columbia. As a postdoctoral scholar at Woods Hole Oceanographic Institution from 2012-2015, he used a wide range of observations to study nearshore currents along the US east coast. At Moss Landing, he has continued his research in the shallow waters near the coast, while also returning to some of his favorite topics in the California Current System: seasonal currents, submarine canyons, and biogeochemical impacts of coastal upwelling.