• The effect of whitecaps and foam on wind speed extraction with a pulse limited radar altimeter

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      https://www.ias.ac.in/article/fulltext/jess/095/02/0265-0273

    • Keywords

       

      Radar altimeter; Seasat; wind speed; specular point model; two-layer media

    • Abstract

       

      The effect of whitecaps and foam on wind speed extraction with a pulse limited radar altimeter has been studied using a specular point model. By modelling foam and water as a two-layer media, we have investigated the changes in reflectivity as a function of thickness using electro-magnetic field theory. Our analysis indicated a change of reflectivity from a value of 0.617 at 13.9 GHz normal incidence to a value of 0.10 for a foam thickness of less than 1 cm. The values of reflectivity computed from a two-layer model compared fairly well with these derived using an emissivity model.

      The modified specular point model gave an improved relationship between σo and wind speed in comparison to Brown’s model. The Seasat altimeter’s data analysis over the Arabian sea and the Bay of Bengal gave an rms difference of 2.2 m/sec in wind speed retrieval using the present modified model and Brown’s model.

    • Author Affiliations

       

      R M Gairola1 P C Pandey1

      1. Meteorology and Oceanography Division, Space Applications Centre, Ahmedabad - 380 053, India
    • Dates

       
  • Journal of Earth System Science | News

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