CR prepress abstract  -  DOI:

Projection of future monsoon precipitation over the central Himalayas by CMIP5 models under warming scenarios

Indira Kadel*, Takeshi Yamazaki, Toshiki Iwasaki, Muhammad Rais Abdillah


ABSTRACT: 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 Himalaya in and around Nepal in the present climate (1971–2000). The evolution of precipitation during three tri-decadal periods of the twenty-first century (2011–2040, 2041–2070 and 2070–2099) under two 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 credible simulation of spatial distribution of SMS mean climatology and interannual variability (IAV). Seasonal mean precipitation is projected to increase considerably in all future periods under both warming scenarios, with a consistent increase in the middle and late twenty-first century. However, the change in IAV of seasonal mean precipitation is uncertain 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 to study regional climate change and its consequences.