Tao Lian, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China, Jie Wang, Shanghai Jiao Tong University, Hangzhou, China, Chunzai Wang, State Key Laboratory of Tropical Oceanography, SCSIO, Chinese Academy of Sciences, Guangzhou, China and Dake Chen, Second Institute of Oceanography, Ministry of Natural Resources, State Key Laboratory of Satellite Ocean Environment Dynamics, Hangzhou, China