诱发云南麻栗坡特大山洪泥石流的暴雨成因分析

Analysis on the Cause of the Heavy Rain Which Caused the Mudslide in Malipo, Yunnan Province

  • 摘要: 利用常规气象资料、NCEP FNL 1°×1°再分析资料、FY-2G卫星TBB(相当黑体亮温)资料、雷达资料分析2018年9月2日麻栗坡猛硐特大山洪泥石流的气象成因,结果表明:猛硐位于100 hPa热带东风急流入口区右侧,500 hPa上位于两高压之间的相对低压区,在700 hPa风场上,猛硐附近存在风向辐合切变,高低层系统的配置为此次大暴雨提供了非常有利的环流条件;猛硐上空存在大量水汽辐合流入,上升气流强大且深厚,整层大气层结对流不稳定,因此极易引起暴雨的发生和发展;强降水时段与强雷达回波对应关系较好,ET(回波顶高)和TBB资料都显示猛硐位于两个对流云团的结合处,分析其原因可能是较强的辐合,配合有利地形抬升作用导致局地强降水;山高沟深以及土质疏松的地形地貌特点,也是导致本次特大泥石流的原因之一。

     

    Abstract: Conventional meteorological data, FNL 1°×1° reanalysis data, FY-2G satellite TBB data and radar data were used to analyze the meteorological causes of the devastating mudslides occurred on 2 September 2018 in Mengdong, Malipo. Results showe that: (i) Mengdong was located on the right side of the entrance area of 100 hPa tropical easterly jet, and it was located in the area of relative low pressure between two high pressures on 500 hPa. In the 700 hPa wind field, there was wind convergence shear near the Mengdong, the configuration of the high and low layer system provided very favorable circulation conditions for the heavy rain. (ii) There was a large amount of water vapor convergence and inflow over the Mengdong, and the updraft was strong and deep, and the whole layer of atmosphere was unstable, so it was easy to cause the occurrence and development of heavy rain. (iii) The corresponding relationship between heavy precipitation period and strong radar echo was good. Both ET and TBB data showed that the Mengdong was located at the junction of two convective clouds. The local heavy precipitation might be caused by the strong convergence and favorable terrain uplift. (iv) The characteristics of mountain high and deep gully and loose soil in Mengdong could also be one of the causes of this massive mudslide.

     

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