气候变化是当今世界受到普遍关注的问题之一。气候变化可部分归因于自然循环以及地球气候系统的扰动，而且必然会引起水循环的变化，引起水资源在时空上的重新分布和水资源数量的改变，进而影响生态环境和社会经济的发展。而现有的预估未来的手段之一 - 全球气候模式对区域和流域尺度上的模拟分辨率较粗，很难详细地分析未来气候变化背景下水循环与水资源的时空变化特征，计算量较小的统计降尺度方法逐步得到了较为广泛的推广与应用。本报告第一部分主要介绍了统计降尺度方法的基本原理与分类、基本假设条件以及在国内外的研究应用进展。第二部分系统评价了IPCC AR4中全球气候模式在我国淮河流域地区的模拟性能。第三部分选取模拟能力较好的模式MIROC3.2_hires开展在淮河流域的统计降尺度和动力降尺度研究，并预估了未来2046-2065年淮河流域的气候变化情景。第四部分选取降尺度效果较好的统计降尺度方法ASD开展在整个东部季风区八个流域的适用性研究，并且预估了八个流域未来2046-2065年气候变化情景。研究结果表明，大部分模式在淮河流域具有较好的模拟能力，模式CNRM_CM3、BCCR_BCM2_0等有一定的优势。气候模式预估21世纪淮河流域气温升高，降水增加。从空间分布上看，整个流域21世纪气温将持续增加，由西北向东南递减，各个季节对升温的贡献大小顺序是：秋季>夏季>冬季>春季；而降水的变化却不完全一致。动力降尺度与统计降尺度的适用性比较表明，两种降尺度结果对降水的模拟比较相近。动力降尺度模拟的平均气温优于统计降尺度。相比较，统计降尺度给出的当代气候情景优于动力降尺度。ASD在东部季风区八个流域的运用表明，未来21世纪中期A1B情景下，ASD模拟的降水变化存在一定的不确定性，而温度存在明显的上升趋势，且年平均和冬季时北方升温高于南方，而夏季时正好相反，但ASD的升温幅度低于GCM。未来年平均的平均温度、最高温度、最低温度分别升高1.68°C、1.75°C、1.65°C。未来八个流域升温趋势显著，但是各个流域不同季节对升温趋势的贡献却有一定的差异。松花江流域、东南诸河和珠江流域的年平均降水是增加的，而黄河流域、海河流域、淮河流域和长江流域的年平均降水却是减少的，辽河流域降水变化不明显。GCM与ASD对降水的预估存在很大的不一致性。八大流域在未来21世纪中期的持续增温趋势是不可避免的，而降水量变化存在一定的不确定性。

Climate change is one of key issues concerned in the world. Climate change can be partially attributed to the natural cycle, as well as disturbance of the Earth's climate system, and will inevitably lead to changes in the water cycle, and will cause the temporal-spatial redistribution of water resources and changes of the amount of water resources. Nowadays One of the existed methods to evaluate the future change - global climate models is too coarse for the regional and watershed-scale research, and is difficult to detailed analysis of spatial and temporal variations of the water cycle and water resources in the context of future climate change, so the statistical downscaling method, less calculation, has gradually been more widely promoted. Performance of 14 GCMs from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) in simulating air temperature and precipitation over the Huaihe River basin has been assessed, and the changes in the 21st century are projected in the first part. The results suggest that all GCMs show good simulation ability for air temperature and precipitation over the Huaihe River basin, but most of them underestimate air temperature and overestimate precipitation. The model CNRM_CM3, BCCR_BCM2_0 etc. display better simulated ability. Although the scenarios projected by 14 GCMs vary greatly, all models project consistent increasing trends in air temperature and precipitation in most regions of the Huaihe River basin in the 21st century. Performance of the statistical downscaling method (ASD) and dynamical downscaling method (RegCM3) is compared in the Huaihe River basin, and large scale information from the same coarse resolution general circulation model MIROC3.2_hires is used. The results show that both of methods display smilar ability for air temperature, but the ASD method exhibits better simulation ability than the RCM method in precipitation.Finally, the statistical downscaling method-ASD is used to evaluate the climate scenario over the Eastern monsoon region. The high resolution daily precipitation, daily air temperature, daily maximum temperature and daily minimum temperature are generated for the present and the future (2046-2065). In the future the change of precipitation is uncertain and the air temperature is obvious increasing. But the increasing range of temperature from ASD is lower than that of GCM. There is an obvious increasing trend in air temperature among each river basin, but the contribution of every season is different among each river basin. The increasing trend in precipitation is existed over the Songhuajinag, Dongnan, Zhujiang River basin, and the decreasing over Huanghe, Haihe, Huaihe and Changjiang River basin, and no obvious change over Liaohe River basin. There are lots of inconsistencies of precipitation change between GCM and ASD.