资源环境科技发展态势分析平台

The credibility of 38 global climate models (GCMs) participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) is assessed to simulate the spatiotemporal variability of the summer monsoon season (SMS) precipitation over the central Himalayas in and around Nepal in the present climate (1971-2000). The evolution of precipitation during 3 tridecadal periods of the 21st century (2011-2040, 2041-2070 and 2070-2099) under 2 warming scenarios: representative concentration pathways (RCP) 4.5 and RCP8.5, are analyzed based on the systematically selected best models and their multi-model mean. Most of the models capture the annual cycle. However, most are deficient in their simulation of spatial distribution of SMS mean climatology and interannual variability (IAV). Models consistently project a considerable increase in seasonal mean precipitation in the middle and late 21st century under both warming scenarios. However, there is inconsistency in projections of the change in IAV of seasonal mean precipitation in all future periods. The increase in the seasonal mean is contributed to mainly by intensification of moderate to heavy precipitation events and the enhanced frequency and length of active spells. Increased precipitation could be attributed to the increase in moisture flux convergence and enhanced low level circulation. Inconsistency in the spatial distribution of the future projections of SMS precipitation change by the best models indicates the uncertainty of the projections and suggests careful interpretation of projections is required in the study of regional climate change and its consequences.