Fan Zhang, Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China, Jian Lin, Woods Hole Oceanographic Inst, G & G, Woods Hole, MA, United States, Jiangyang Zhang, Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China and Hongfeng Yang, Earth System Science Programme, Faculty of Science, Chinese University of Hong Kong, Hong Kong, Hong Kong