| 摘要: |
| 为探究冬季南支槽活动频次对我国同期南方降水的影响，利用ERA-interim逐日再分析资料，基于低压槽客观识别技术，对1979—2015年冬季的南支槽活动进行了识别，并使用相关性分析、合成分析等方法分析了两者之间的年际关系。结果表明：南支槽活动频次指数（SBTI）与南方冬季降水存在着显著的正相关关系，当南支槽活动偏多（少），易造成西藏中部、重庆地区、湖北西部、贵州东北部等地降水偏多（少）。南支槽的活动影响南方冬季降水的主要原因是：当南支槽偏多年时，700 hPa风场的距平图上华南地区位于一“异常气旋”外围，500 hPa位势高度距平图上自高纬的冷空气和自低纬的暖湿气流在高原以南、西南地区聚集，有利于西南到长江中游一带降水偏多；当南支槽偏少年时，700 hPa风场的距平图上西南、华南受“异常反气旋”外围的偏北风控制，500 hPa位势高度距平图上南方地区处于单一暖湿气流的影响，使得西南、华南及长江中下游以南的地区降水偏少。 |
| 关键词: 南支槽活动；大气环流；冬季南方降水 |
| DOI： |
| 投稿时间：2019-08-03 |
| 基金项目:贵州省气象局科研业务登记项目（黔气科登[2018]09-03号）：冬季南支槽的年际变化及其影响因子研究；中国气象局预报员专项（CMAYBY2019-105）：贵州东南部致灾暴雨短临预报技术总结分析 |
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| Interannual relationship between the Southern Branch Trough activity in winter and the precipitation in southern China |
| WU Shuyan,ZHANG Chao,WANG Weiping,WANG Minmin,CHEN Xiaodan |
| (Liping Count Meteorological Bureau of Guizhou Province,Liping 557300 ,China;Qiandongnan Meteorological Bureau of Guizhou Province,Kaili 556000 ,China;Guizhou Climate Center,Guiyang 550002 ,China) |
| Abstract: |
| With ERA-interim reanalysis data, activities of Southern Branch Trough (SBT) in winter during 1979—2015 a were identified based on objective identification technique to investigate the impact of SBT activity on the winter precipitation in southern China, and interannual relationships between them were analyzed using correlation analysis, composite analysis, etc. Results show that: There is a significant positive correlation between the index of Southern Branch Trough activity (SBTI) and precipitation in southern China in the same period, which indicates the more (less) active SBT is, the more (less) precipitation will be in central Tibet,Chongqing, western Hubei,and northeastern Guizhou. The main reason for SBT activity affecting winter precipitation in the southern China is that southern China is in peripheral region of an “anomalous cyclone” in the years of more SBT. Meanwhile, in geopotential height at 500 hPa,cold air from higher latitude and warm air from lower latitude converge in Southwest and southwestern Tibetan Plateau(TP), benefitting Southwest to the Middle Reaches of the Yangtze River more precipitation.In years of less SBT,Southwest and southern China is controlled by northerly wind cause in peripheral region of an “anomalous anticyclone”at 700 hPa. At the same time,southern China is influenced by single warm and humid air flow in geopotential height at 500 hPa,leading to less precipitation in Southwest, southern China and the South of the Middle and Lower Reaches of the Yangtze River. |
| Key words: southern branch trough activity；atmospheric circulation；precipitation in southern China in winter |
