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

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.