Changes in Precipitation-based Extremes Indices Due to Global Warming Projected by a Global 20-km-mesh Atmospheric Model

Future changes in extremes indices on precipitation were projected with a 20-km horizontal grid atmospheric general circulation model. At the end of the 21st Century, heavy precipitation was shown to increase enormously in South Asia, the Amazon, and West Africa, while a dry spell was shown to increase in South Africa, south Australia, and the Amazon, suggesting that the risk of water-related disasters will be higher in these regions. In the Asian monsoon region, heavy precipitation increases notably in Bangladesh and in the Yangtze River basin due to the intensified convergence of water vapor flux in summer. In the Amazon, a dry spell greatly increases due to a reduction in the Walker circulation caused by an El Nino-like change in SST prescribed as boundary condition.