摘要
统计降尺度方法广泛应用于弥补大气环流模式(GCM)模拟区域气候变化能力较弱的不足。利用1960～2009年的NCEP/NCAR再分析资料和江淮流域52个站点降水观测资料,通过敏感性分析,针对4个季节分别选择10个大尺度预测因子,采用主成分分析(PCA)和支持向量机(SVM)相结合的方法,建立了江淮流域降水统计降尺度模型。检验结果表明,该模型获取的江淮流域降水的偏差显著减小,能够描述降水在月、年尺度的变化,适用于HadCM3输出的大尺度气候场,具有预测未来降水变化的能力。将统计降尺度模型应用于HadCM3在A2情景下输出的2020～2099年大尺度预测因子,分3个时段:2020～2039年,2050～2069年和2080～2099年,从年和季节两个时间尺度分析江淮流域未来降水变化。结果表明,相对1960～1999年,未来3个时段的降水有小幅增加,其中2080～2099年增幅最大,为3.6 mm;在未来3个时段的不同季节,降水变化呈现出不同特征。
Statistical downscaling is widely used to make up the shortcomings of General Circulation Model（GCM） in simulating regional climate change.A statistical downscaling model with GCM precipitation is developed for the Yangtze-Huaihe region.Using the NCEP/NCAR re-analysis data and the observed precipitation of 1960-2009 at 52 meteorological stations in the region,a model linking 10 large-scale atmospheric variables（predictors） to the local precipitation amount is proposed.A combined approach of Principal Component Analysis（PCA） and Support Vector Machine（SVM） is used for training the model to establish a statistical relationship between the 10 predictors and the local precipitation amount for the Yangtze-Huaihe region.The results show that the model can significantly reduce the precipitation error compared to that of using GCM simulations directly,and the monthly and annual variations in precipitation can be better described.The model is then applied to the HadCM3 simulation of the SRES A2 scenario for three time periods 2020-2039,2050-2069 and 2080-2099.Both seasonal and annual variations in the projected future precipitation for the Yangtze-Huaihe region are analyzed.Compared to the baseline（1960-1999） period,a relatively small increase in precipitation could be expected to the climate change during the period 2020-2099.Among which,the highest increase in the precipitation rate of 3.6 mm/a could be in the period 2080-2099.The seasonal precipitation changes are different from each other during the three time periods.
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2012年第1期29-37,共9页
Advances in Water Science
基金
国家重点基础研究发展计划(973)资助项目(2011CB403202)
中国科学院寒区旱区陆面过程与气候变化重点实验室开放基金(LPCC201102)~~
关键词
统计降尺度
降水
支持向量机
江淮流域
statistical downscaling
precipitation
support vector machine
Yangtze-Huaihe region
