Radiometric calibration accuracy of airborne synthetic aperture radar in ocean surface wind field sounding

Abstract

Sounding accuracy is difficult to study systematically and effectively because of complex airborne synthetic aperture radar system. In this paper, according to the role of radiometric calibration accuracy in ocean surface wind field sounding process of airborne synthetic aperture radar, a method is proposed to investigate the system sounding accuracy by radiometric calibration accuracy. The parameter relationship of CMOD4 geophysical model function is simulated. The radiometric calibration accuracy of airborne synthetic aperture radar ocean surface wind field sounding at different incidence angles and in wind directions is ascertained. The results show that the radiometric calibration accuracy decreases with incidence angle increasing and changes periodically with wind direction changing. The law is accordance with the change of backscattering cross-section, cased by wind speed in CMOD4 geophysical model function. According to this law, we find that the accuracy of ocean surface wind field retrieval can be improved by using active calibration scale, designing carrier aircraft crosswind flight and selecting the large incidence angle sounding imagery as retrieval area.