The polarimetric features of an oyster farm in a coastal area are analyzed to verify the applicability of radar polarimetry and interferometry. L-band Airborne Synthetic Aperture Radar (AIRSAR) data and Japan Earth Resources Satellite (JERS-1) data are used to examine the unique structure of an oyster farm located in South Korea. A specific feature of the oyster farm is the presence of numerous arrays of structures of various orientations that consist of exercise-bar-shaped poles protruding above sea level. This paper demonstrates that tide level is strongly correlated with the double-bounce scattering power from the vertical pole structures. This phenomenon is also verified by laboratory measurements using a network analyzer. In the laboratory experiment, double-bounce scattering and total power showed increasing trends with increased height of the vertical poles. Single-bounce scattering is sensitive to the orientation of horizontal poles relative to antenna orientation. HH-polarization is the most effective technique for imaging oyster farms from L-band polarimetric AIRSAR data. The authors were able to use a three-component decomposition of the AIRSAR data to distinguish an exposed tidal flat from a submerged tidal flat. The characteristics of the exposed tidal flat are similar to those of the carbon sponge in the laboratory test, except that the double-bounce scattering power is slightly greater in the real-world example. The single-bounce scattering component in AIRSAR data is generally greater than that in laboratory measurements because of sea-surface conditions and oyster growth. When the horizontal pole was aligned normal to the radar look direction, single-bounce scattering was greater than the double-bounce scattering, even under water-covered conditions. While a difference in tide height of 10 cm contributed approximately 3.0 dB in the laboratory experiment, a difference in tide height of 20 cm contributed to only approximately 1.7 dB in the JERS-1 SAR image intensity. JERS-1 SAR image intensity for areas dominated by double- and single-bounce scattering was 0.78 and 0.56, respectively. Results confirm that polarimetric SAR data are useful in selecting areas dominated by double-bounce scattering in oyster farms.
|Number of pages
|IEEE Transactions on Geoscience and Remote Sensing
|Published - 2006
Bibliographical noteFunding Information:
Manuscript received October 14, 2005; revised May 7, 2006. This work was supported by the Yonsei University Research Fund of 2004. S.-K. Lee, S.-H. Hong, and J.-S. Won are with the Department of Earth System Sciences, Yonsei University, Seoul 120-749, Korea (e-mail: jswon@ yonsei.ac.kr). S.-W. Kim is with the Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149 USA. Y. Yamaguchi is with the Department of Information Engineering, Niigata University, Niigata 950-2181, Japan. Digital Object Identifier 10.1109/TGRS.2006.879107 Fig. 1. Scattering in an oyster farm structure (S1: single-bounce scattering from a horizontal pole; S2: single-bounce scattering from a vertical pole; D1: double-bounce scattering from a horizontal pole; D2: double-bounce scattering from a vertical pole).
All Science Journal Classification (ASJC) codes
- Electrical and Electronic Engineering
- General Earth and Planetary Sciences