GENERATION OF CALIBRATED WIND WAVE SLOPES IMAGES FROM THE ENVISAT POLARIMETRIC DATA

• Main Authors: Sergey Pereslegin, Igor Elizavetin, Andrey Ivanov
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Asar; Newfoundland; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.396.7737

A new method for the direct measurements of an anisotropic wind induced sea waves is proposed. It exploits the polarimetric spaceborne SAR data to derive the main wave parameters. It was shown that the ratio of like-polarized and cross-polarized components of sea backscattered signal contains the direct information on slopes of wind induced waves. It is especially applicable to the high resolution SAR images because it allows to evaluate the level of waves spatial anisotropy. Also, it was shown that the radar intensities correspond to waves structure in area of atmospheric vortexes. The result had been confirmed via processing of experimental data acquired over Newfoundland, North Atlantic region from ASAR ENVISAT polarimetric data set. 1. ANALYTICAL APPROACH 1.1. Retrieving of RCS polarimetric components In this paper the simplified analysis of the polarimetric components of radar cross section (RCS) is proposed. It takes into account a spatial anisotropy of large sea waves. The analysis is based on preceding works [1,2] and regards two problems. At first, it’s an evaluation of the intensities of like-polarized and cross-polarized components (LPC and CPC), on second, it’s a possibility for measurements of anisotropic waves parameters without anyway internal or external RCS calibration, i.e. on the relation of intensities of the polarimetric components of backscattered signal. defined by accepted model of spectrum of the developed wind-induced waves. For simplification, an equation (1) was approximated by exponent, concerning to middle viewing angle θ