摘要
利用1960-2012年川渝逐日降水资料、NCEP/NCAR再分析资料和Hadley海温资料,借助小波变换、合成分析和相关分析等方法,讨论了四川盆地夏季暴雨的时空变化特征,分析了盆地西部和东部暴雨异常时的水汽输送、大气环流和海温异常情况。结果表明,四川盆地暴雨频数和暴雨量在东、西部呈相反变化,盆地西部暴雨呈减少变化,东部呈增加变化,暴雨量和暴雨频数存在十分显著的正相关。盆地西部暴雨量在20世纪60年代和80年代偏多,90年代出现显著减少的变化,21世纪初也明显偏少,20世纪60年代、80年代中期至90年代末主要为显著的6~7年年际周期振荡;盆地东部暴雨量在60年代和70年代明显偏少,80年代、90年代以及21世纪初明显偏多,20世纪70年代初至90年代初主要存在显著的8~9年年际周期振荡和14~15年的年代际周期振荡。副热带高压(简称副高)偏北偏强,有利于西太平洋水汽输送至盆地西部地区,中高纬度槽线发展引导冷空气南下与副高西南侧的暖湿气流在盆地西部汇合,导致盆地西部暴雨偏多;副高偏南,西太平洋水汽向盆地东部输送较多,贝加尔湖西部多阻塞形势,冷空气南下有所偏东,使得冷空气和暖湿空气在盆地东部汇合,导致盆地东部暴雨偏多。西太平洋暖池偏强(弱),ENSO冷(暖)事件时,四川盆地西部暴雨偏多(少);盆地东部暴雨与海温的关系明显弱于西部,主要表现为负相关。
Based on the observed daily precipitation data and NCEP/NCAR reanalysis data from 1960 to 2012, the temporal and spatial variation of rainstorm in Sichuan Basin were discussed, and the water vapor transport, atmospheric circulation and sea surface temperature anomaly in the west and east of the Basin were analyzed by using the composite anomaly, correlation analysis, wavelet analysis and so on. The main conclusions are as fol- lows： The rainstorm frequency and rainstorm amount showed the opposite changes in the east and the west of Sichuan Basin, the rainstorm increased in the west and decreased in the east, there was a significant positive cor- relation between rainstorm precipitation and frequency. The rainstorm in the west of Sichuan Basin was extremely more in 1960s and 1980s, while abnormally less in 1990s and early 21st Century, which mainly existed a 6 - 7 years inter-annual oscillation period in 1960s and from the mid-1980s to the end of the 1990s. The rainstorm in the east of Sichuan Basin was obviously less in 1960s and 1970s, while abnormally more in 1980s, 1990s and early 21st Century, which significantly existed 8-9 years inter-annual oscillation period and 14-15 years inter- decadal oscillation period from the beginning of 1970s to the beginning of 1990s. When the West Pacific Subtrop- ical High shifts northward and become stronger, the Western Pacific water vapor will be more easily transported to the west of Sichuan Basin. These lead to rainstorm in the west of Sichuan Basin. By contrast, when the West Pacific Subtropical High shifts southward, the Western Pacific water vapor will be transported to the east of Sichuan Basin; under the situation of blocking pattern in the west of Lake Baikal, the southward moving path of the cold air tend to the east, so the cold air and warm wet air converge in the east of Sichuan Basin, cause more rainstorm in the east of the Basin. The rainstorm in west Sichuan Basin shows significant negative correlation with the West Pacific Warm Pool and ENSO events the east of Sichuan Basin is much weaker than The relationship between rainstorm and sea surface temperature in in the West.
出处
《高原气象》
CSCD
北大核心
2018年第1期197-206,共10页
Plateau Meteorology
基金
国家自然科学基金项目(41775084)
高原大气与环境四川省重点实验室开放课题(PAEKL-2018-C4)
中国气象局成都高原气象研究所基本科研费业务费(BROP201713)
关键词
四川盆地
暴雨
副热带高压
水汽输送
西太平洋暖池
Sichuan Basin
rainstorm
West Pacific Subtropical High
water vapor transport
Western PacificWarm Pool
