How Large Precipitation Changes over Global Monsoon Regions by CMIP5 Models?

Future changes in precipitation over global monsoon domains and their adjacent dry regions are investigated using present-day climate simulations (1986-2005) and future climate simulations under the Representative Concentration Pathways (RCP4.5) scenario by the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. In the present-day climate simulations, high reproducibility of the extents of global monsoon domains and dry regions is observed from the multi-model ensemble (MME) result; the associated local summer precipitation variation and its interannual variability are also successfully reproduced. In the future, the global monsoon domains are projected to be expanded, while the dry regions are expected to initially increase and then decrease. The summer precipitation and its variability show significant increases over most global monsoon domains and obvious decreases over their adjacent dry regions. These results indicate that currently wet regions will become wetter and dry areas will be dryer under global warming conditions. Further analysis indicates that changes in summer precipitation over global monsoon and dry regions can be interpreted as moisture convergence changes associated with changes in horizontal moisture transport.