中国南方冬季持续性温湿异常事件的分类和特征分析  

Classification of persistent winter temperature-precipitation anomalies in southern China and their large-scale atmospheric conditions

作　　者：田青 温敏[1,2] 张人禾[1,3] 高辉 

机构地区：[1]中国气象科学研究院,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,南京210044 [3]复旦大学大气科学研究院,上海200433 [4]国家气候中心,北京100081

出　　处：《气象学报》2017年第5期729-743,共15页Acta Meteorologica Sinica

基　　金：国家重点研发计划"全球变化及应对"重点专项项目(2016YFA0600602);国家重点基础研究发展规划"973"项目(2012CB417205);中国气象科学研究员基本科研业务费项目(2015Z001)

摘　　要：利用1981—2010年中国测站逐日气温和降水异常序列,将中国南方冬季持续性异常事件分为冷湿、冷干、暖湿和暖干4类持续性异常事件,并用NCEP-DOE逐日再分析资料对各类持续性异常事件的环流特征进行了分析。结果表明,欧亚大陆中高纬度上空"北高南低"的异常环流形势使得温带急流减弱、副热带急流增强,有利于冷空气向南爆发;而中纬度地区"东高西低"的异常环流则对应西太平洋副热带高压增强北移和南支西风槽的活跃,有利于偏南风水汽输送达到中国南方地区,中国南方降水偏多。受南北异常环流的共同影响,中国南方冬季经常出现持续性异常天气,冷湿(低温雨雪冰冻)事件正是在上述两种异常环流型影响下发生的。因此,考虑与冷湿事件相联系的关键环流系统可能有助于提高中国南方冬季低温雨雪冰冻事件的预报能力。Based on daily temperature and precipitation observations collected at weather stations in China during 1981-2010,persistent anomalous events in southern China are identified and classified into four types,i.e.cold-wet-event,cold-dry-event,warm-wet-event,and warm-dry-event.Features of large-scale atmospheric circulations associated with the four types of events are examined using the National Centers for Environmental Prediction-Department of Energy（NCEP-DOE）reanalysis data.The anomalous ＂north high-south low＂ pattern in geopotential height over Eurasia in the middle and high latitudes results in a weaker than normal temperate jet and a stronger than normal subtropical jet,which are favorable for the southward invasion of cold air.On the other hand,the anomalous ＂west low-east high＂ pattern over the subtropics indicates that the subtropical western Pacific High is stronger and shifts farther north than normal,while the southern branch trough deepens.The southerlies in front of the trough transport abundant water vapor into southern China and increase precipitation there.Jointly affected by anomalous circulations both in middle and higher latitudes and in the subtropics,southern China often experiences various persistent abnormal events during winter.Among them,the wet-cold event occurs when the above two anomalous patterns appear simultaneously.Therefore,our results suggest that the prediction skill of severe freezing disaster weather over southern China would be improved if taking into account the variations of key circulations associated with cold-wet events.

关 键 词：冷湿事件 持续性异常 环流特征 冬季气候 中国南方 

分 类 号：P462.41[天文地球—大气科学及气象学]