四川巴中地区引发滑坡地质灾害的强降水类型及典型案例分析

Different Types of Heavy Rainfall Which Triggered the Landslide in Sichuan Bazhong Area and Typical Case Analysis

运用巴中地区区域自动站逐日、逐小时降水资料和NCEP 1? ×1?间隔为6 h的再分析资料分析了巴中地区降水气候特征,并具体对比分析巴中地区引发滑坡的三种不同类型强降水特征,得出结论如下:1) 巴中地区年降水量整体表现为“南北多、东西少”的分布特征。强降水事件集中发生在6~9月,可分为持续性强降水、突发性暴雨和连续性暴雨三种类型。2) 窑厂坪的滑坡由持续性强降水引发,特点是降雨持续时间长,小时降水强度变化不大,累积降水量大。黑马山滑坡由突发性暴雨引发,其特点是降水持续时间短,累积降水量大。老河沟后山滑坡由连续性暴雨引发,特点为降水过程中出现多次强降水,强降水间有数小时的时间间歇。3) 三次降水过程前期中高纬经向环流强盛,且均出现高空急流,但其主要影响系统略有不同。4) 三次强降水过程前期在低层均有明显的偏北气流存在,冷空气由北向南侵入,存在较强的对流性不稳定能量,垂直上升运动较强,但上升运动出现的高度存在差异。

By using the weather station precipitation and NCEP 1? ×1? reanalysis data, this paper analyzed the climate characteristics of precipitation and the characteristics among three different types of heavy rain events which triggered the landslides in Sichuan Bazhong area, and the results show that: 1) The annual precipitation in southern and northern is more than eastern and western of Bazhong area. 2) Yaochangping landslide triggered by persistent heavy rainfall, which characterized by long duration, little change of hourly precipitation and large accumulation precipitation. Heimashan landslide is triggered by sudden rainstorm, which is characterized by short duration and large accumulation precipitation. Laohegou landslide triggered by continuous rainstorm, characterized by two or more times of precipitation events with several hours of intermittent during the entire precipitation process, the landslide occurred in the mid-late period of the precipitation process. 3) Strong meridional circulation occurs early in three rainfall events in high latitudes, but its main impact system is slightly different. 4) There was significantly northern airflow existing in the low level during the prophase of the three heavy precipitations and the cold airflow irrupted from north to south direction, with strong convective instability energy and with strong vertical upward movement. However, the height differences emerged during the upward motion.