Remote sensing applications in satellite oceanography

Satellite remote sensing provides repeated global observations of key ocean surface variables. These observations are complementary to in situ measurements. In fact, remotely sensed information fills some in situ gaps in temporal and spatial coverage, while in situ measurements, being a point-wise source of informa- tion, provide critical ground-truth for satellite retrievals calibration and validation. Advances in satellite ocean technology and algorithm research make satellite remote sensing an indispensable tool for environmental monitoring of the open and coastal ocean. Moreover, remotely sensed products support the interpretation and the pre- diction of oceanic phenomena that occur at regional and mesoscales in a synoptic way. In this chapter, we introduce basics of satellite oceanography, including the most used satellite orbits, the range of frequencies involved, and the processing levels related to the remote sensed products. Then, selected ocean products and their applications, from ocean color to infrared observations of sea surface temperature, passive microwaves, and altimetry, are addressed. Finally, a special attention is devoted to synthetic aperture radars (SARs) and the emerging role of microsatellites in observing ocean variables and, in particular, wind speed.