ABSTRACT
This chapter describes altimeter wind speed observations, their quality, and their importance for monitoring the quality of modeled surface wind the altimeter significant wave height (SWH), which is four times the square root of the total wave energy. It summarizes the applications of altimeter wind and wave observations and presents a few developments in satellite sea state measurements. The necessary calibration and validation of a satellite sensor requires large amounts of ground truth that should cover the full range of possible events. In particular, the number of reliable wave in situ measurements is very limited and, because of financial restrictions, dedicated field campaigns are possible only at a few sites. For the purpose of altimeter wind speed verification, an in situ wind speed measurement is only trusted if it is associated with an acceptable SWH value. One plausible reason for the seasonal cycle in the altimeter bias may be related to the presence of slicks.
