Future Changes in the Baiu Rain Band Projected by a 20-km Mesh Global Atmospheric Model: Sea Surface Temperature Dependence

Global warming projection experiments were conducted using a 20-km mesh global atmospheric model (the 20-km model), focusing on the change in the rain band of the East Asian summer monsoon (the Baiu rain band in Japan). To quantify the dependence of the projected change on the sea surface temperature (SST) prescribed to the 20-km model, we have taken different SSTs given by the two Atmospheric-Ocean General Circulation Model (AOGCM)s of MRI-CGCM2.3.2 and MIROC(hires). In the future climate simulations, the Intergovermental Panel on Climate Change (IPCC) A1B emission scenario was assumed. The future climate simulations show that precipitation and its intensity increase over the Yangtze River valley of China and Western Japan. The termination of the Baiu season tends to be delayed until August. These changes were consistently found in the simulations regardless of different SSTs.