Simultaneous radiometric and radar altimetric measurements of sea microwave signatures

We discuss the advantages provided by the combined use of a polarization microwave radiometer and a short-pulse radar altimeter for sea roughness monitoring. A brief analysis of the potential of each device taken separately is carried out, which shows the advisability of their combination. The method and the results of the experiment performed with an airborneK-band radiometer and an altimeter are described. It is shown that, in regions of fully developed roughness, a correlation exists between the polarization characteristics of the microwave radiation by the sea surface and the rms sea waveheight as measured by the altimeter. Correlation is not found in regions where the roughness is not developed. Therefore, the combination of the two instruments makes it possible to sense the regions of fully developed sea roughness.     

Selection of Pulse Repetition Frequency in High-Precision Oceanographic Radar Altimeters

A readily computable formula to perform versatile analysis of the nonstationary pulse-to-pulse correlation properties of ocean altimeter returns is presented. Using this formula, the correlation coefficient and correlation interval depending on the reference time, sea state, and system parameters have been analyzed. The results have suggested that the pulse repetition frequency should adaptively be adjusted to the sea state to ensure precise altitude measurements.