TERRAPUB Journal of Oceanography

Journal of Oceanography, Vol. 54 (No. 5), pp. 417-430, 1998

Correction of Atmospheric Effect on ADEOS/OCTS Ocean Color Data: Algorithm Description and Evaluation of Its Performance

Hajime Fukushima1, Akiko Higurashi2, Yasushi Mitomi3, Teruyuki Nakajima4, Toshimitsu Noguchi5, Toshio Tanaka6 and Mitsuhiro Toratani1

1School of High-Technology for Human Welfare, Tokai University, Numazu, Japan, 317 Nishino, Numazu, 410-0395 Japan
2National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, Japan
3Remote Sensing Technology Center, Roppongi, Minato-ku, Tokyo 106, Japan
4Center for Climate System Research, University of Tokyo, Komaba, Meguro-ku, Tokyo 153, Japan
5Information &Communication Systems Laboratory, Toshiba Corporation, Suehiro-cho, Oume, Tokyo 198-8710, Japan
6Space Systems Group, LTCB Systems Co., LTD., 1-1-17, Kamiohsaki, Shinagawa, Tokyo 141-0021, Japan

(Received 31 March 1998; in revised form 20 June 1998; accepted 30 June 1998)

Abstract: This paper first describes the atmospheric correction algorithm for OCTS visible band data used at NASDA/EOC. Sharing a basic structure with Gordon and Wang's SeaWiFS algorithm, it uses 10 candidate aerosol models including the "Asian dust model" introduced in consideration of the unique feature of aerosols over the east Asian waters. Based on the observations at 670 and 865 nm bands, the algorithm selects a pair of aerosol models that account best for the observed spectral reflectances, and synthesizes the aerosol reflectance used for the atmospheric correction. Two different schemes for determining the value of the parameter for the aerosol model selection are presented and their anticipated estimation error is analyzed in terms of retrieved water reflectance at 443 nm. The results of our numerical simulation show that the standard deviation of the estimation error of the "weighted average" scheme is mostly within the permissible level of ±0.002, reducing the error by 18% on average compared to the "simple average" scheme. The paper further discusses the expected error under the old CZCS-type atmospheric correction, which assumes constant aerosol optical properties throughout the given image. Although our algorithm has a better performance than the CZCS algorithm, further analysis shows that the error induced by the assumption taken in the algorithm that the water-leaving radiance at 670 nm band is negligibly small may be large in high pigment concentration waters, indicating the necessity for future improvements.


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