Upwelling usually occurs in the spring. The coastal ocean off western North America has received considerable oceanographic study because of its fisheries and proximity to large human populations. The oceanography of this region is strongly influenced by the process of coastal upwelling. In general, coastal upwelling occurs along eastern ocean margins when equatorward winds act in combination with the Coriolis force to move surface waters offshore, drawing deeper water to the surface.
Upwelled water is nutrient-rich, and supports high levels of phytoplankton and higher trophic level.
In the northeast Pacific, coastal upwelling occurs seasonally. From 1989 to 1998 a total of 206 cruises have been completed, collecting samples from over 600 stations. Several other stations were sampled including minor coastal station 'H1', outer bay station 'C7', and sections of CalCOFI Line 67. Plus CTD mounted in a General Oceanics 12 bottle rosette with 5 liter Niskin bottles fitted with silicon O-rings. Profiling data was collected on the downcast where conductivity, temperature and depth data were collected at 24 Hz and processed with modified Sea-Bird software that bins the data to 1 meter intervals.