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Revised ocean backscatter models at C and Ku-band under high wind conditions

William Joseph Donnelly, University of Massachusetts Amherst


This dissertation will analyze airborne C and Ku-band ocean backscatter measurements collected with the University of Massachusetts' C and Ku-band scatterometers (CSCAT and KUSCAT) during the numerous field experiments of the past eighteen months. The emphasis will be on demonstrating the limitations of the current empirical models that relate ocean backscatter to the near surface wind at high wind speeds. The discussion focuses on winds in excess of 15 $\rm m{\cdot}s\sp{-1}.$ The scatterometer data is collocated with ocean data buoys and GPS dropsondes, and a Fourier analysis is performed as a function of wind regime. A three-term Fourier cosine series is fit to the backscatter data and a revised set of coefficients is tabulated. This revised model is the basis for a discussion of the NRCS at high winds. The data show a clear over-prediction of the derived NRCS response to high winds based on the current empirical models CMOD4, SASSII and NSCAT1. Furthermore, saturation of the NRCS response is evident. Sensitivity of the upwind and crosswind response is discussed. The effects of precipitation on C and Ku-band NRCS estimates are explored.

Subject Area

Electrical engineering

Recommended Citation

Donnelly, William Joseph, "Revised ocean backscatter models at C and Ku-band under high wind conditions" (1998). Doctoral Dissertations Available from Proquest. AAI9841864.