基于IPCC情景下新疆地区未来气候变化的预估

新疆地区地形复杂且地面观测站点分布稀疏,降低了以往基于中国地区的气候变化预估效果。在降尺度方法中,偏差校正方法相对于区域气候模式和统计降尺度方法,对于区域气候变化预估更加实用和经济。本文采用Delta方法对24个GCMs模型月数据降尺度至0.5°水平分辨率,分析A1B、A2和B1三个情景下新疆未来气候变化格局。结果表明到2099年三个情景下年平均气温分别为10.0℃、11.1℃和8.5℃,年降水量有显著的增加趋势。在中天山地区、伊犁河流域、天山南坡和塔里木河下游地区的带状区域增温幅度小于北疆准噶尔盆地、帕米尔高原和昆仑山北坡。对于年降水量,在南疆西部相对于参考时期呈现微弱的减少趋势,在昌吉地区、吐鲁番地区、哈密地区和昆仑山北坡-阿尔金山一带呈现显著性的增长趋势。

Projection of Climate Change in Xinjiang under IPCC SRES

With global climate change,the annual temperature shows a significantly increasing trend in China,especially in Xinjiang.However,despite the rising temperature,snow cover on both Tianshan Mountains and Qinghai-Tibet Plateau has been showing slightly ascending trend.It means that climate change has great uncertainty in spacial distribution.The Global Climate Model(GCM)is an efficient and direct method to assess the process of global climate change under variable forces,especially the human activity.To improve the resolution of GCM,there are three main downscaling methods,i.e.Dynamic Downscaling Method,Offset Correction Method and Statistical Downscaling Method.Dynamic Downscaling Method is to calculate the output of GCMs again by using the Regional Climate Model or Numerical Weather Prediction Model.Statistical Downscaling Method is a bit difficult to directly gain the raster outputs in terms of coping with each station’s data.Offset Correction Method is in the lead on accuracy and efficiency,especially on regional scale research.As one of the Offset Correction methods,Delta method was applied to downscale the horizontal resolution of 24 GCMs’monthly outputs to 0.5 degree in this study and to analyze Xinjiang’s future climate change pattern under three scenarios ie.A1B,A2 and B1.The results show that:1)By the end of the 21st century,the annual mean temperature under the above three scenarios would be 10.0℃,11.1℃and 8.5℃respectively and the annual precipitation will have prominent increase tendency;2)Temperatures in the middle Tianshan Mountains,the Ili River watershed,the southern slope of Tinahsan Mountains and the stripe region in the lower reaches of Tarim river increase slower than those in Junggar Basin,Pamirs and northern slope of Kunlun Mountains;3)The annual precipitation shows slightly decreasing trend in the west of southern Xinjiang,but shows significantly increasing trend in Changji,Turpan,Hami and northern Kunlun-Altun Mountains.