• JAGDISH PRAJAPATI

      Articles written in Journal of Earth System Science

    • Orientation of marine atmospheric rolls in a SAR imagery using wavelet transform: A case study over Bay of Bengal

      JAGDISH PRAJAPATI BIPASHA PAUL SHUKLA RAJ KUMAR

      More Details Abstract Fulltext PDF

      An objective wavelet based algorithm has been developed to find the orientation of rolls in Synthetic Aperture Radar (SAR) imagery using Radar Imaging Satellite (RISAT-1) data. The orientation of rolls plays a very crucial role for the estimation of ocean surface wind direction. It also affects the shape and size of a tropical cyclone. In this manuscript, SAR image was decomposed using Haar Wavelet Transform (HWT) and optimal thresholding was done to delineate the direction of propagating rolls. The roll features were found oriented in the range 26$^{\circ}$–31$^{\circ}$ from the along track direction. These features are very useful to retrieve wind direction and hence the vector wind observation over the ocean surface.

      $\bf{Highlights}$

      $\bullet$ Development of a new algorithm to find the orientation of MABL rolls in the SAR imagery.

      $\bullet$ Use of Haar Wavelet Transform due to its high computational efficiency and ease of potential operational application.

      $\bullet$ The study is first of its kind over the Indian Ocean.

      $\bullet$ Rolls are oriented between 26$^{\circ}$ to 31$^{\circ}$ from the along track direction.

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