Guojian Wang, Centre for Southern Hemisphere Oceans Research (CSHOR), CSIRO Oceans and Atmosphere, Hobart, Australia, Wenju Cai, CSIRO Oceans and Atmosphere, Aspendale, Australia, Lixin Wu, Ocean University of China, Qingdao, China, Boris Dewitte, LEGOS, Toulouse, France and Ken Takahashi, Servicio Nacional de Meteorología e Hidrología, Lima, Peru