Changes of Atmospheric Water Balance over China under the IPCC SRES A1B Scenario Based on RegCM3 Simulations

Abstract

Simulations of the Regional Climate Model Version 3 (RegCM3) under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario were employed to inves- tigate possible decadal changes and long-term trends of annual mean atmospheric water balance components over China in the 21st century with reference to the period of 1981-2000. An evaluation showed that RegCM3 can rea- sonably reproduce annual evapotranspiration, precipita- tion, and water vapor transport over China, with a better performance for March-June. It was found that the water vapor exchange between the land surface and atmosphere would be significantly intensified in Northwest China by the mid- to late-21st century and that the region would possibly shift to a wetter or drought-mitigated state under global warming. Conversely, the water vapor exchange evidently weakened over the Tibetan Plateau and South- west China by the mid- to late-21st century. In addition, there appears to be a drier state for Northeast China and the middle and lower reaches of the Yangtze River valley by the mid- to late-21st century, with slight mitigation by the end compared with the mid-21st century. The westerly and southwesterly water vapor transport over China gen- erally presents an increasing trend, with increasing diver- gence over the Tibetan Plateau and Northeast China, cor- responding to a loss of atmospheric water vapor by water vapor transport. Keywords: RegCM3, A1B scenario, atmospheric water balance Citation: Sun, B., and D.-B. Jiang, 2012: Changes of atmospheric water balance over China under the IPCC SRES A1B scenario based on RegCM3 simulations, At- mos. Oceanic Sci. Lett., 5, 461-467.