北京气候中心次季节-季节预测系统对西南地区夏季降水次季节预报技巧评估及误差订正  

Evaluation and Bias Correction on the Subseasonal Forecast of Summer Precipitation over Southwestern China Forecasted by the Beijing Climate Center Sub-seasonal to Seasonal Predication System

作　　者：郭渠[1] 黄安宁[2] 付志鹏 唐红玉[1] 李永华[1] 何慧根[1] GUO Qu;HUANG Anning;FU Zhipeng;TANG Hongyu;LI Yonghua;HE Huigeng(Chongqing Climate Center,Chongqing 401147,China;School of Atmospheric Science,Nanjing university,Nanjing 210023,Jiangsu,China)

机构地区：[1]重庆市气候中心,重庆401147 [2]南京大学大气科学学院,江苏南京210093

出　　处：《高原气象》2021年第3期644-655,共12页Plateau Meteorology

基　　金：国家重点研发计划项目(2016YFA0602104);国家自然科学基金项目(41875111,41605068);中国气象局预报员专项(CMAYBY2019-096);中国气象局预报预测经费数值模式发展专项[YBSZMSXM(2019)-03]。

摘　　要：利用北京气候中心(BCC)次季节-季节(Sub-seasonal to Seasonal,S2S)预测系统20年(1994-2013年)回报试验数据,在评估BCC S2S预测系统对中国西南地区夏季降水次季节预报性能基础上,进而采用基于奇异值分解(Singular Value Decomposition,SVD)的误差订正方案对预测结果进行订正。结果表明:BCC S2S预测系统对西南地区夏季降水的次季节预报技巧随起报时间的提前不断下降,在起报时间提前10天以内具有一定预报技巧,而在起报时间提前10天以上基本无技巧,同时存在明显的区域性和年际差异。采用SVD误差订正方案能够较好改善BCC S2S系统对西南地区夏季降水的次季节预测水平,起报时间提前0~10、11~20、21~30天原始预测结果与观测间的异常相关系数分别为0.50,0.31和0.25,订正后分别提高至0.70,0.75和0.70,同时订正后的预测结果与观测间的空间相关系数在起报时间提前0~10天提高了0.3左右,尤其对起报时间提前11~30天的预测结果改进更加明显,空间相关系数提高了0.6左右。The capability of the Beijing Climate Center(BCC)sub-seasonal to seasonal(S2S)prediction system in forecasting the summer precipitation in Southwestern China has been evaluated based on the 20-year(1994-2013)hindcast data.Meanwhile,the singular value decomposition(SVD)bias correction scheme was subsequently adopted to improve the forecast skill of the BCC S2S prediction system.The results show that the skill of BCC S2S prediction system in forecasting the summer precipitation over Southwestern China was decreases continuously with the early forecast lead time.It shows certain forecasting skills within 10 days ahead of the starting time,but basically has no skills exceeding 10 days ahead of the starting time.In addition,the forecast skill exhibits obvious regional and inter-annual differences.The sub-seasonal prediction skill of the summer precipitation in Southwestern China could be well improved by adopting the SVD bias correction scheme.The abnormal correlation coefficients between the original prediction results and observations are 0.50,0.31 and 0.25 with the forecast lead time of 0~10,11~20,21~30 days,which are increased to 0.70,0.75 and 0.70 after the correction,respectively.Moreover,in comparison with the spatial correlation coefficient(SCC)between the bias original prediction results and observations,the SCC between the bias corrected prediction results and observations is increased by about 0.3 at the forecast lead time of 0~10 days,especially for the prediction results with the forecast lead time of 11~30 days,the spatial correlation coefficient for the bias corrected results is significantly increased by 0.6 compared to the original results.

关 键 词：夏季降水 中国西南 次季节-季节预测 奇异值分解 误差订正 

分 类 号：P435[天文地球—大气科学及气象学]