Yoshimitsu Chikamoto, Utah State University, Department of Plants, Soils & Climate, Logan, UT, United States, Axel Timmermann, Pusan National University, IBS Center for Climate Physics, Busan, South Korea, Matthew J Widlansky, University of Hawaii at Manoa, JIMAR, Honolulu, HI, United States, Shaoqing Zhang, Ocean University of China, Qingdao, China and Balmaseda Magdalena, European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom