The climatology of 850 hPa wind and rainfall in observations and CMIP5 models is shown in Fig. 11.1. In observations (Fig. 11.1A), the strong southwesterly winds flow from the Indian Ocean to the Bay of Bengal (BOB), all the way to the northern SCS, and then turn to eastern China, the Korean peninsula, and Japan. The southwesterly winds affect the climate in East Asia with the southerly winds originating from the northwestern flank of the western Pacific subtropical high (WPSH; the anticyclone circulation over the western Pacific). The monsoon rainfall band is dominated by the WPSH.