1. International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii, 2525 Correa Road, Honolulu, HI 96822, USA.
2. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
3. Physical Oceanography Laboratory, Ocean University of Qingdao, Qingdao 266003, China.