夏季长生命史盆地涡活动对川渝季节降水的影响  

Mechanism of Long Lifespan Sichuan Basin Vortex's Activity Influence the Precipitation in Sichuan-Chongqing Region on Summer

作　　者：李超[1,2] 李跃清[3] 蒋兴文[3] 

机构地区：[1]中国气象局武汉暴雨研究所,武汉430205 [2]暴雨监测预警湖北省重点实验室,武汉430205 [3]中国气象局成都高原气象研究所,成都610072

出　　处：《高原气象》2017年第3期685-696,共12页Plateau Meteorology

基　　金：国家自然科学基金项目(91337215;41275051);国家重点基础研究发展计划课题(2012CB417202);四川省应用基础研究计划重点项目(2016JY0046);国家公益性行业(气象)科研专项(GYHY201006053)

摘　　要：利用ERA-interim再分析资料和全国824个国家气象站的日降水资料,分析了1983—2012年夏季发生在四川盆地且生命史大于等于24 h(定义为长生命史)的低涡年际变化特征和成因,以及它对川渝地区季节降水的影响,研究结果表明:夏季长生命史的盆地涡的涡源主要位于盆地西南部附近和东北部附近,根据涡源位置的差异可将盆地低涡分为西南型和东北型。由于夏季长生命史西南型盆地涡出现频数远大于东北型盆地涡,因此长生命史西南型盆地涡对季节累积降水贡献较大,但是进一步分析发现长生命史东北型盆地涡产生的日降水强度较强,降水范围较广。长生命史西南型盆地涡由于较少移动,其主要影响区位于初生源地附近的局地地区,而长生命史东北型盆地涡由于移动性较强,其主要影响区位于副热带高压外围的较大范围地区。从季节尺度来说,影响两类低涡频数变化的关键大气环流因子有显著差异,当中纬度长波槽偏强,副热带高压西伸明显加强,以及高原南支绕流偏强时,有利于更多长生命史西南型盆地涡的生成;而当南亚高压强度偏弱,高纬度西伯利亚高压脊稳定维持,以及西伸的副热带高压边缘正好位于云贵高原东部地区附近时,有利于更多长生命史东北型盆地涡的生成。Based on the ERA-interim reanalysis data and the daily meteorological precipitation data of 824 China stations during 1983 and 2012,we analysed the inter-annual variation of Sichuan Basin Vortex（SBV） whose lifespan is equal to or more than 24 hours（defined as long lifespan） and the corresponding cause,as well as its influence on seasonal precipitation on summer. The main conclusions are as follows：（1） The birthplace of long lifespan SBV was located in southwest and northeast of Sichuan Basin,SBV could be classified into two types（ Southwest Type and Northeast Type） based on the birthplace.（2） The frequency of Southwest Type was much higher than Northwest Type,and Southwest Type contributed much more to seasonal precipitation as a result,however Northeast Type caused much more daily precipitation and influenced broader region in mostly case. Because Southwest Type was stable and less dynamic,its influenced region was limited within its birthplace. However,Northeast type was active,its influenced area was surrounded subtropical high. There was obvious difference on precipitation range between Southwest Type and Northeast Type.（3） As to seasonal scale,the key atmosphere circulation factors which influenced the frequency of the two types were various from each other. When the intensity of long wave trough in middle attitude got stronger,the subtropical high extended westward more,besides the South Branch Trough of the plateau got stronger,it was advantageous to produce more Southwest Type SBV. On the contrary,when the intensity of South Asia high got weaker,Siberia high ridge was stably maintained,as well as the edge of subtropical high was just located near the east of Yun Gui Plateau,it was advantageous to produce more Northeast Type SBV.

关 键 词：西南涡 四川盆地低涡 季节降水 大气环流因子 

分 类 号：P448[天文地球—大气科学及气象学]