1. Lab of remote sensing & information technology, Guangdong Ocean University, Zhanjiang, China
2. State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
3. Gad Levy, west Research Associates, Inc. 4118 148th Ave NE, Redmond, WA 98052-5164, USA
4. Danling Tang, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West XinGang Road, Guangzhou, China, 510301