统计降尺度方法和Delta方法建立黄河源区气候情景的比较分析  

COMPARATIVE ANALYSIS ON DOWNSCALED CLIMATE SCENARIOS FOR HEADWATER CATCHMENT OF YELLOW RIVER USING SDS AND DELTA METHODS

作　　者：赵芳芳[1] 徐宗学[1] 

机构地区：[1]北京师范大学水科学研究院水沙科学教育部重点实验室,北京100875

出　　处：《气象学报》2007年第4期653-662,共10页Acta Meteorologica Sinica

基　　金：北京师范大学"京师学者"特聘教授启动经费。

摘　　要：大气环流模型(GCMs)预测的气候变化情景,必须经降尺度处理得出小尺度上未来气候变化的时空分布资料,才能满足气候变化对资源、环境和社会经济等影响进行评估的需要。文中研究同时应用Delta方法和统计降尺度(SDS)方法对黄河源区的日降水量和日最高、最低气温进行降尺度处理,建立起未来3个时期(2006—2035、2036—2065和2066—2095年,简记为2020s、2050s和2080s)的气候变化情景,并比较分析两种方法的优缺点和适用性。结果表明,未来降水量有一定的增加趋势,但是增幅不大,而日最高、最低气温存在明显的上升趋势,且增幅较大。与基准期相比,Delta方法模拟的未来3个时期降水量将分别增加8.75%、19.70%和18.49%;日最高气温将分别升高1.41、2.42和3.44℃,同时,日最低气温将分别升高1.49、2.68和3.76℃,未来极值气温变幅减小。SDS法借助站点实测数据和NCEP再分析资料建立GCM强迫条件下的降尺度模型,模拟结果表明,未来3个时期降水量将分别增加3.47%、6.42%和8.67%,季节变化明显;气温随时间推移增幅明显,未来3个时期的日最高气温将分别升高1.34、2.60和3.90℃,最低气温增幅相对较小,3个时期将分别升高0.87、1.49和2.27℃,由此模拟的未来时期无霜期将延长。在降尺度方法的应用上,SDS方法存在明显的优势,但同时也存在不可避免的缺陷。因此,在实际的气候变化影响评估中,需要多种方法综合比较,以期为决策部门提供参考和依据。General circulation models （GCMs） results suggest that the increasing concentration of greenhouse gases will have significant implications for climate on global and regional scales. Less confidence exists on the extent to which meteorological processes will be affected at individual site. The so-called ＇downscaling＇ techniques are used to bridge the spatial and temporal resolution gaps between that what the climate modelers are currently able to provide and that what the impact assessors require. Strategic-scale assessments of climate change impacts are often undertaken by using the Delta method where the future climate changes projected by GCMs are applied to the baseline climatology. Alternatively, statistical downscaling （SDS） methods apply climate variables from GCMs to statistical transfer functions to estimate the point-scale meteorological series. The relative merits of the SDS and Delta methods are investigated in this paper by using a case study of scenarios in the headwater catchment of the Yellow River basin under baseline （1961 - 1990） and climate change conditions （2020s, 2050s and 2080s）. The climate change scenarios for daily precipitation and daily maximum/minimum temperature are generated by using the SDS and Delta methods, and the results show that there is a small increasing trend for the precipitation and an obvious increasing trend for the maximum/minimum daily temperature in the study periods. These departures are explained in terms of the different treatment for the multi-decadal natural variability, temporal structure of daily climate variables and large-scale forcing of local precipitation and maximum/minimum temperature by two downscaling methods. Compared with the results in the baseline for Delta scenarios, the changes of precipitation in the future are very big, it will increase 8.75 %, 19.70 % and 18.49 %, respectively; the daily maximum temperature will increase 1.41 ℃ , 2.42 ℃ and 3.44 ℃ in the future, and the daily minimum temperature will increase 1.49 �

关 键 词：气候变化 大气环流模型(GCMs) 情景 降尺度 黄河 

分 类 号：P457.6[天文地球—大气科学及气象学]