INFLUENCE OF TYPHOON IN THE EAST CHINA SEA ON THE SOUTHWEST VORTEX RAINSTORM IN SICHUAN PROVINCE
-
摘要: 利用NCEP逐6 h的FNL再分析资料、地面气象站逐小时降水资料以及中尺度数值模式WRF对2010年9月5日14时—6日20时发生在四川东部的一次西南涡暴雨天气过程进行诊断分析和数值研究。重点探讨了东海远距离台风对西南涡的移动和维持、水汽输送作用。结果表明:(1)这次川东暴雨是在中纬度30~50 °N的两槽一脊的环流背景下,川西高原的东移低值系统(西南涡)受位于东海的北上台风间接阻挡,及源于南海和孟加拉湾的水汽不断输送等有利条件下形成的;(2)台风“玛瑙”并未向西南涡降雨区直接输送水汽;(3)东海台风“玛瑙”对上游东移的西南涡具有阻挡作用:台风的出现,使西风带上游东移的系统(含西南涡)东移的速度减慢,西南涡因此在四川东部地区滞留时间延长,是造成该地区暴雨天气发生的重要原因。Abstract: Using NCEP 6-hourly reanalysis data、the hourly rain data and the mesoscale numerical model WRF, the southwest vortex rainstorm (SVR) occurred in the eastern part of Sichuan province from 5th September, 2010, 14pm (UTC+8) to 6th, 20pm is diagnostically analyzed and numerically simulated.Intensive discussions are made about the impact of typhoon in the East China Sea on movement and maintenance of the southwest vortex and the transportation of water vapor. The results show as follows. (1) The SVR in eastern Sichuan province was formed under favorable conditions.Such as the circulation background of "two troughs and one ridge" in the mid- latitude 30~50 °N, the eastward moving low system (southwest vortex) of the western plateau of Sichuan province was indirectly blocked by the northward typhoon in the East China Sea, and the water vapor from the South China Sea and the bay of Bengal was continuously transported to the storm area. (2) Typhoon"Malou" did not transport water vapor to the southwest vortex rainstorm area. (3) The typhoon in the East China Sea had a "blocking" effect on the moving eastward southwest vortex: the speed of Eastward system (including southwest vortex) in westerlies upstream slowed down because of the effect of typhoon, and prolonging the "retention" time of southwest vortex in the eastern part of Sichuan province, which played an important role in causing the heavy rainfall in the region.
-
Key words:
- southwest vortex /
- typhoon /
- rainstorm /
- numerical simulation /
- transfer of water vapor
-
表 1 台风“玛瑙”路径误差
时间/h 6 12 18 24 30 36 42 48 误差/km 86.08 96.24 109.83 108.26 103.04 110.31 112.35 113.42 -
[1] 陈忠明, 闵文彬, 崔春光.西南低涡研究的一些新进展[J].高原气象, 2004, 23(S1): 1-5. [2] 钱正安, 顾弘道, 颜宏, 等.四川"81.7"特大暴雨和西南涡的数值模拟[J].气象学报, 1990(4): 415-423. [3] 陈忠明, 徐茂良, 闵文彬, 等. 1998年夏季西南低涡活动与长江上游暴雨[J].高原气象, 2003, 22(2): 162-167. [4] 杨帅, 丁治英, 徐海明.梅雨暴雨中高低空急流与西南涡的活动[J].南京气象学院学报, 2006, 29(1): 122-128. [5] 刘富明, 杜文杰. 触发四川盆地暴雨的高原涡的形成和东移, 下半年青藏高原对我国天气的影响[C]//青藏高原气象研究文集. 北京: 科学出版社, 1987: 123-124. [6] 陈忠明, 闵文彬, 缪强, 等.高原涡与西南涡耦合作用的个例诊断[J].高原气象, 2004, 23(1): 75-80. [7] 陈忠明, 黄福均, 何光碧.热带气旋与西南低涡相互作用的个例研究Ⅰ:诊断分析[J].大气科学, 2002, 26(3): 352-360. [8] 李强, 刘德, 陈贵川, 等.基于WRF模式热带气旋对西南低涡暴雨作用数值试验研究[J].长江流域资源与环境, 2013, 22(3): 359-368. [9] 康岚, 郝丽萍, 罗玲, 等. 1002号台风对四川盆地大暴雨的影响分析[J].热带气象学报, 2013, 29(1): 169-176. [10] 周国兵, 沈桐立, 韩余.台风对西南低涡影响的数值模拟与诊断个例分析[J].气象科学, 2006, 26(6): 620-626. [11] 李云川, 张迎新, 马翠平, 等.热带低压远距离对西南涡稳定加强的作用[J].高原气象, 2012, 31(6): 1551-1561. [12] SKAMAROCK W C, KLEMP J B, DUDHIA J, et al. A description of the advanced research WRF Version 3[J]. NCAR Technical Note, 2008, 88: 7-25. [13] DRAXLER R R, HESS G D. An overview of the HYSPLIT_4 modeling system for trajectories, dispersion and deposition[J]. Australian Meteorolog Mag, 1998, 47(2): 295-308.