统计降尺度方法及其评价指标比较研究

针对目前气候变化对水资源影响研究中关注的问题,以汉江白河上游为研究对象,比较研究统计降尺度方法及其评价指标。以美国环境预报中心/美国国家大气研究中心全球再分析资料、CGCM3和HadCM3的A2情景为大尺度气候背景资料,应用SSVM和SDSM统计降尺度方法对大尺度气候因子进行尺度降解,得到降水情景序列后作为水文模型的输入,通过模拟径流比较分析统计降尺度方法的优劣。研究结果表明,由不同统计降尺度方法得到的降水作为水文模型输入,模拟径流的结果相差很大;对广泛应用于统计降尺度方法的降水模拟评价指标和径流模拟结果进行比较,发现所采用的降水评价指标侧重于考虑降水的统计分布特征,不能完整地描述降水过程特性。分析认为,径流模拟结果应该作为气候变化对径流影响研究中统计降尺度方法评价的重要参考。

Comparison of different statistical downscaling methods and evaluation indicators in climate change impact on runoff

The application of statistical downscaling techniques and their evaluation indicators in climate change impacts studies on runoff in Hanjiang basin were compared and assessed by focusing on the key issues of climate change impacts studies on water resources currently. The NCEP/NCAR global reanalysis data and CGCM3 and HadCM3 under A2 scenario being the background of large-scale climate, large-scale climate factors were downscaled by using SSVM and SDSM statistical downscaling techniques, which were used as inputs for hydrological models. Then the simulated runoffs corresponding to various scenarios were analyzed comprehensively. The results show that for the same GCM, the simulation results of runoff vary greatly by using precipitation as the input to hydrological models through different statistical downscaling techniques. Evaluation indicators of precipitation simulation and runoff simulation results through statistical downscaling techniques demonstrate that rainfall runoff calculation cannot be fully utilized in evaluation indicator system of precipitation. While the evaluation of runoff simulation should be a key reference in turn to asses the simulation of precipitation by using the downscaling method in the climate changes impact on runoff.