新疆21世纪气候变化的高分辨率模拟

Climate Change over Xinjiang Region in the 21st Century Simulated by a High Resolution Regional Climate Model

使用一个25km高水平分辨率区域气候模式(RegCM3),嵌套MIROC3.2_hires全球气候模式结果,进行了IPCC SRES A1B情景下,东亚区域21世纪气候变化的模拟,针对新疆地区进行了分析.首先对模式模拟的当代(1981—2000年)气候进行检验,结果表明:模式对年平均气温、降水的空间分布和数值均具有较好的模拟能力,但与观测相比,模拟的气温一般在盆地偏高、山区偏低,降水则在盆地偏少、山区偏多.在IPCC SRES A1B温室气体排放情景下,21世纪中期(2041—2060年)及末期(2081—2100年)新疆地区冬、夏季气温均将升高,末期的增温幅度更大,特别是在末期的冬季.降水除个别地区外将普遍增加,同样末期增加更多.在不同地形条件下,气温和降水的变化特点均有所不同,其中盆地增温大、山区增温小,降水量在山区和盆地过渡地带的变化最明显,以增加为主并表现出一定的季节特征.相对于全国平均而言,新疆地区的增温和降水量增加更显著.

Based on a high resolution simulation of the 21st century by a regional climate model（RegCM3） nested within a global climate model（MIROC3.2_hires） over East Asia,climate changes over Xinjiang Region under the IPCC SRES A1B scenario are analyzed.Validation of the model performances in simulating annual mean temperature and precipitation of present time（1981—2000） in the region are firstly carried out.Results show that the spatial distributions and amount of them are well reproduced by the model.Compared to observations,it is found that the model exhibits a warm bias over basins and cold bias over mountainous areas.Moreover,underestimation of precipitation in the basins and overestimation of it over mountain ranges are found in the simulation.Significant warming is simulated in the middle（2041—2060） and the end of the 21st century（2081—2100） over the region,while greater warming in the end of the century,in particular in winter,are found.General increase of precipitation is found both in winter and summer,except in portions of the region.The increase is more profound in the end of the century compared to the middle of it.In addition,the magnitude of the warming and amount of the precipitation increase show strong dependency on topography.In general,the warming is greater over basins,while the increase of precipitation amount is more significant over mountain slopes with seasonal difference.As for the regional mean,greater warming and precipitation increase are found in Xinjiang Region compared to those over the whole China.