典型相关分析方法对21世纪江淮流域极端降水的预估试验

利用1961—1990年江淮流域逐日降水资料、NCEP/NCAR再分析资料和HadCM3 SRES A1B情景下模式预估资料，采用典型相关分析统计降尺度方法，评估降尺度模型对当前极端降水指数的模拟能力，并对21世纪中期和末期的极端降水变化进行预估。结果表明：通过降尺度能够有效改善HadCM3对区域气候特征的模拟能力，极端降水指数气候平均态相对误差降低了30%～100%，但降尺度结果仍然在冬季存在湿偏差、夏季存在干偏差；在SRES A1B排放情景下，该区域大部分站点的极端强降水事件将增多，强度增大，极端强降水指数的变化幅度高于平均降水指数，且夏季增幅高于冬季；冬季极端降水贡献率（R95t）在21世纪中期和末期的平均增幅分别为14%和25%，夏季则分别增加24%和32%。

Projection of Extreme Precipitation Events in the 21st Century in the Changjiang-Huaihe River Valley Based on Canonical Correlation Analysis

Based on the observed daily precipitation data at 26 meteorological stations in the Changjiang-Huaihe River valley, and the NCEP/NCAR reanalysis data from 1961 to 1990 as well as the climate projections in middle and late 21st century by the HadCM3 model under the IPCC SRES A1B, the simulation capabilities of the statistical downscaling approach for extreme precipitation indices of the current climate have been assessed by applying canonical correlation analysis (CCA). In addition, future extreme precipitation indices in middle and late 21st century have been projected. The results show that the modeling capacity of the HadCM3 for regional climate characteristics can be effectively improved by the downscaling approach, with reducing the relative error of the climatological average state of extreme precipitation indices by 30% -100%. However, the downscaling results are still wetter in winter and dryer in summer than observations. Under the SRES A1B, frequency and intensity of extreme precipitation events are projected to increase, and the estimated increasing rate is higher for extreme precipitation index than for average one, and in summer than in winter. Fractions of extreme precipitation in middle/late 21st century are expected to increase by 14% / 25% in winter, and by 24% / 32% in summer, respectively.