Swell parameters retrieval using ALOS/PALSAR data and its application

Y. L. Wei, H. Kawamura, Z. Y. Tang

Research output: Contribution to journalConference articlepeer-review


We have developed retrieval methods for swell parameters such as wave height, wavelength, and wave propagation direction from images of PALSAR on board ALOS taken over coastal seas around Japan. The retrieval methods for wavelength and wave direction use the PALSAR image spectrum. The SAR image spectrum has an inherent 180° direction ambiguity, which can be solved using the fact that the swells only propagate toward the coast. Using the coupling swell spectra and the PALSAR image spectra, an empirical L-band modulation transfer function was obtained for the wave height retrieval through linear regression analysis. A comparison between SAR-derived and in situ wave parameters showed close agreement. For the wavelength and wave direction, the biases were 10.4 m and 1.3° the root mean-square errors (RMSE) were 18.3 m and 15.5° and the correlation coefficients were 0.93 and 0.94, respectively. These results demonstrate that the L-band SAR imaging mechanism for swells is mostly linear. For the wave height, the bias was 0.08 m, the RMSE was 0.30 m, and the correlation coefficient was 0.80. The coastal water depth was calculated from the retrieved wavelength. The comparison shows that the result is better when the water depth is less than 50 meters.

Original languageEnglish
Article number012120
JournalIOP Conference Series: Earth and Environmental Science
Issue number1
Publication statusPublished - 2014
Event35th International Symposium on Remote Sensing of Environment, ISRSE 2013 - Beijing, China
Duration: 2013 Apr 222013 Apr 26

ASJC Scopus subject areas

  • Environmental Science(all)
  • Earth and Planetary Sciences(all)


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