Analyses on the climate change responses over China under SRES B2 scenario using PRECIS

The PRECIS, a regional climate model system developed at the UK Met Office Hadley Centre for Climate Prediction and Research, which is nested in one-way mode within the HadAM3P, a higher-resolution version of the atmospheric component of the Hadley Centre climate model HadCM3, is employed to simulate the baseline (1961-1990) climate for evaluation of model's capacity of simulating present climate and analyze the future climate change responses in the time-slice of 2071-2100 (2080s) under SRES B2 scenario over China relative to baseline average. It is indicated from the comparison of the simulated baseline climate with in situ observation that PRECIS can simulate the local distribution characteristics of surface air temperature over China quite well; generally speaking, the simulation for precipitation in the north of China and in winter is better than in the south of China and in summer, respectively; the simulation of precipitation in summer is sensitive to topography, and the simulated precipitation values are lower than observations over southeast coastal areas. It is shown from the analyses on the simulated climate change responses in 2080s under SRES B2 scenario relative to baseline that there would be an obvious surface air temperature increase in the north of China relative to that in the south of China, and especially in Northwest China and Northeast China, the amplitude of summer mean surface air temperature increments could reach 5 degrees C; there would be an overall increase of the simulated precipitation in 2080s under SRES B2 scenario over most areas of China, while there would be significant precipitation decreases in South China in winter; there would be obvious precipitation decreases in Northeast China and North China in summer with high surface air temperature increase. However, it presents an obvious precipitation increase over the middle and lower reaches of the Yangtze River in summer.