考虑不同背景场低频降水的延伸期预测  

Extended range forecasting of low-frequency precipitation under different background circulations

作　　者：曲金华[1,2] 王一舒 谭桂容[3] QU Jin-hua;WANG Yi-shu;TAN Gui-rong(Department of Science and Technology and Forecast of Jilin Meteorological Service,Changchun 130062,China;Jilin Provincial Key Laboratory of Changbai Mountain Meteorology ＆ Climate Change,Changchun 130062,China;Key Laboratory of Meteorological Disaster,Ministry of Education（KLME）,Joint International Research Laboratory of Climate and Environment Change（ILCEC）,Nanjing 210044,China)

机构地区：[1]吉林省气象局科技与预报处,吉林长春130062 [2]长白山气象与气候变化吉林省重点实验室,吉林长春130062 [3]南京信息工程大学气象灾害教育部重点实验室,江苏南京210044

出　　处：《气象与环境学报》2018年第5期57-65,共9页Journal of Meteorology and Environment

基　　金：国家自然科学基金(41630424);国家科技支撑计划子项目(2015BAC03B02)共同资助

摘　　要：基于中国国家气象观测站的逐日降水资料、NCEP逐日全球再分析资料和NOAA逐日向外长波辐射资料,选取与10—30 d低频降水相关显著的热带、中高纬环流作为影响因子,针对1979—2013年江南4—6月延伸期低频降水,依照不同背景场下低频降水与影响因子之间的相关性,进行了预测试验。结果表明:江南4—6月降水以10—30 d的低频周期最为显著。印度洋、印尼附近的热带对流和欧亚高纬度地区的大气环流共同影响着我国江南4—6月低频降水,可作为延伸期降水的预测因子。当欧洲及西西伯利亚地区位势高度出现负距平、北美及贝湖以西附近位势高度正距平,且热带对流异常偏弱时,对应江南低频降水异常偏少,异常中心主要位于长江中下游地区; 30 d以上的大尺度500 h Pa低频位势高度场主要表现为3种空间分布型,根据这3种分布型可将逐日降水个例的大尺度背景场划分为3类,每种背景场下低频降水与热带、中高纬度环流因子在前期30 d内的相关特征均不同; 30 d以上时间尺度的500 h Pa低频环流可为10—30 d延伸期变化提供相对稳定的大尺度背景场,不同背景场下区域低频降水与相应低频环流之间的关系演变不同。考虑不同背景,其相关性增强,且显著相关超前的时间更长。Based on daily precipitation observations from the national meteorological observatories,daily outgoing longwave radiation data from NOAA,and reanalysis data from the NCEP （National Centers for Environmental Prediction）,an extended range forecasting for the low-frequency precipitation over south of the Yangtze River during April,May,and June （AMJ） from 1979 to 2013 was carried out under different background circulations.The atmospheric circulations over tropic or mid-high latitude,which are significantly correlated with the 10-30 d low-frequency precipitation,were selected as the influencing factors.The results show that the 10-30 d component of the AMJ precipitation over south of the Yangtze River is the most significant.The precipitation anomalies are significantly related to the tropical convection locates over the eastern Indian Ocean and Indonesia,as well as the atmospheric circulation anomalies over the high latitude of Europe and Siberia.They can be selected as the predictors for the extended range precipitation.When the geopotential height anomalies over the high latitude of Europe and Siberia areas appear to be suppressive,while over North America and west to the Lake Baikal appears to be active,moreover,the tropical convective appears to be suppressive,the rainfall over south of the Yangtze River turns scarce.The center of the rainfall anomaly locates in the middle and lower reaches of the Yangtze River.Based on the spatial distributions of geopotential height anomalies at the period longer than 30 days at 500 hPa,the low-frequency background of daily precipitation is divided into three categories.The correlation in -30 lag days between low-frequency precipitation and predictors exhibits their individual features in each background.The 500 hPa low-frequency circulation at the period longer than 30 days provides the stable background state for the 10-30 d extended range variations.The correlation between low-frequency precipitation and predictors turns out to

关 键 词：非滤波法 热带-中高纬度共同作用 低频背景场 降水分型预测 

分 类 号：P456[天文地球—大气科学及气象学]