NCEP CFSv2对北半球夏季中高纬阻塞高压的预测检验  

Check Analysis of the Prediction of Northern Hemisphere Blocking in Summer by NCEP CFSv2

作　　者：周宁芳 贾小龙[2,3] ZHOU Ningfang;JIA Xiaolong(National Meteorological Center, Beijing 100081, China;Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science ＆Technology, Nanjing 210044, Jiangsu, China;National Climate center, Beijing 100081, China)

机构地区：[1]国家气象中心,北京100081 [2]南京信息工程大学气象灾害预报预警与评估协同创新中心,江苏南京210044 [3]国家气候中心/中国气象局气候研究开放实验室,北京100081

出　　处：《高原气象》2018年第2期469-480,共12页Plateau Meteorology

基　　金：国家自然科学基金项目(41575090;41520104008;91637208);国家科技支撑计划项目(2015BAC03B04)

摘　　要：利用1999 2010年共12年NCEP CFSv2(NCEP Climate Forecast System version 2)每天4个时次对未来45天预测的回报数据,检验了CFSv2模式对北半球夏季(6 8月)中高纬乌拉尔山区域(10°E70°E)和贝加尔湖-鄂霍次克海区域(110°E 180°E)阻塞高压及其与之相联系的东亚气候的预测能力。分析结果显示,CFSv2可以较好的模拟夏季北半球阻塞高压发生频率的纬向分布特征,但随着预测时效的增加阻塞发生的频率不断降低。CFSv2对两个区域阻塞预测的命中率在7天时效内为50%左右,接近2周之后基本上没有技巧。CFSv2对区域阻塞事件的预测技巧要低于区域阻塞的技巧,贝加尔湖-鄂霍次克海区域阻塞事件的技巧略低于乌拉尔山区域。CFSv2对阻塞爆发和结束的预测超过7天左右,基本没有预测技巧,对乌拉尔山区域阻塞结束日的预测技巧要低于阻塞爆发日的预测技巧。CFSv2在可用的预测时效内可以较好再现与区域阻塞相联系的环流形势以及东亚地区气温、降水异常的分布特征,尤其是夏季乌拉尔山和鄂霍茨克海地区发生阻塞时我国长江流域及其以南地区降水容易偏多的特征。Daily output data from 12-year retrospective forecasts by the National Centers for Environmental Pre- diction （NCEP） Climate Forecast System version 2 （CFSv2） was analyzed to understand the skill of forecasting summertime atmospheric blocking in the Northern Hemisphere and associated climate anomalies in East Asia. Pre- diction skills of sector blocking, sector-blocking episodes, and blocking onset/decay were assessed with a focus on the Ural mountains sector （10°E- 70°E） and the Baikal-Okhotsk sector （110°E- 180°） based on the hit rate, the false alarm rate, the bias score, and the HSS skill scores. Circulation and climate patterns in East Asia associated with blocking in the CFSv2 predictions were also examined. The CFSv2 captures the observed features of longitudinal distribution of blocking activity well, but underestimates blocking frequency and shows a decrea- sing trend in blocking frequency with increasing forecast lead time. Skillful forecast （ if taking the hit rate of 50% as a criterion） can be obtained up to 7 days in both the Ural mountains （10°E--70°E） and the Baikal-Okhotsk （ 110°E -- 180°） sectors. When beyond two weeks, there are nearly little skills. The forecast skill of sector-bloc- king episodes is slightly lower than that of sector blocking in mountains sector than that in the Baikal-Okhotsk sector sector. both sectors, and it is slightly higher in the Ural Compared to block onset, the skill for block decay is slightly lower in the Ural mountains sector, and for both sectors, forecast skills of the block onset and the block decay tend to near zero when forecast lead time beyond 7 days. In both two sectors, a local dipole pattern at 500 hPa geopotential height associated with blocking and associated wave-train like patterns which are far away from the blocking sector can also well represented in CFSv2. The CFSv2 well reproduces the observed character- istics of local temperature and precipitation anomalies associated with the blocking over both sectors. Add

关 键 词：阻塞 北半球 夏季 CFSv2 预测技巧 

分 类 号：P456.7[天文地球—大气科学及气象学]