Development of oceanic wind vector model function for AMSR radiometer on ADEOS-II satellite

Since the advent of the first spaceborne wind scatterometers on NASA's SeaSat mission in 1978, the Advanced Earth Observing Satellite (ADEOS)-II was the first satellite mission that carried both microwave scatterometer and radiometer imagers. This provided a unique opportunity to explore the possibility of combined technology for oceanic surface wind vector measurements. In contrast to conventional scatterometry that require both forward and aft multi-azimuth look measurements, our technique use only forward look radar backscatter measurement combine with collocated brightness temperature measurements to retrieve wind direction. This single-look configuration would be highly beneficial for future satellite mission to obtain improved observation of both oceanic and atmospheric information. Microwave radiometers are well-known instrument for atmospheric and oceanic physical parameters retrieval. Although, the vertical and horizontal brightness temperatures are weakly dependent on wind direction, it has been shown that certain linear combinations of vertical and horizontal brightness temperatures are almost indepentdent of the atmosphere and are predominantly a function of wind speed, direction and sea surface temperature (SST). The empirical relationship for these brightness temperatures was developed for the Advaced Microwave Scanning Radiometer (AMSR) on ADEOS-II. In addition to passive measurement, coincident radar backscatter from foreward look SeaWinds scatterometer was combined to retrieve the wind directions. The wind direction retrieval algorithm and statistical results are presented.