California Sea Grant College Program

In cloudy areas, such as Central California, polar-orbiting satellites obtain relatively few clear glimpses of the ocean surface while geostationary ones have the chance to obtain many. In the case of the GOES-10 satellite, the ocean surface in the Eastern Pacific is scanned 24 times daily by instruments that gather measurements of infrared radiation emitted from the Earth’s surface on a 4-kilometer grid. Infrared radiation levels provide an estimate of ocean surface temperature when the ocean is not obscured by cloud cover.

To construct maps of fronts, the core of the project, the scientists converted estimates of ocean temperature into estimates of temperature gradient—the change in ocean temperature over a certain distance.