重庆市渝东南地区一次大暴雨个例分析
Analysis of a Heavy Rainfall Event in the Southeast of Chongqing

文章利用常规天气观测、卫星、多普勒天气雷达及数值模式资料对2020年6月27日发生在渝东南地区的一次大暴雨天气过程进行了分析。结果表明：1) 渝东南海拔较高的山区，其山地地形对气流有着强迫抬升和辐合作用，较容易触发暴雨或使之加强，因此成为重庆暴雨的高发区。此次降水过程的有利条件是：500 hPa副高南撤，同时伴随高原槽东移发展，700 hPa和850 hPa中低层维持高湿状态且配合持续时间较长的低涡切变、低空急流系统；2) 对流性天气的形成需要三个基本条件：大气不稳定能量、抬升力和水汽。对流有效位能(CAPE)是能用来表示整体大气垂直不稳定度大小的物理含义参数。诊断物理量：K、SI、BLI和整层可降水量对强对流天气的提前预报有较好的指示作用；3) 雷达回波完整地反映了降水趋势，整条回波带由中西部偏南区域延伸到渝东南偏北地区，整体呈长条形，且源源不断自西向东移动，形成列车效应，从而导致渝东南地区持续性降水，整体累积雨量较大，致使渝东南地区北部与回波带重合区域有暴雨到大暴雨的降水，对降水强中心位置有较好的指示作用。
In this paper, using conventional weather observations, satellite data, Doppler weather radar and numerical model data, a heavy rainfall event that occurred in the southeast of Chongqing on June 27, 2020 was analyzed. The results show that: 1) In the high mountain areas of southeast Chongqing, the mountain terrain has a forced lifting and radiation effect on the airflow, which makes it easier to trigger or intensify heavy rain, thus becoming a high-incidence area of heavy rain in Chongqing. The favorable conditions for this precipitation process are: the subtropical high moves southward at 500 hPa, accompanied by the eastward movement of the plateau trough at the same time; the mid-dle and low layers at 700 hPa and 850 hPa maintain a high humidity state and cooperate with a long-lasting low-level shear and low-level jet system; 2) The formation of convective weather re-quires three basic conditions: unstable atmospheric energy, lifting force, and water vapor. Convec-tive Available Potential Energy (CAPE) is a physical parameter that can be used to represent the magnitude of clear overall atmospheric vertical instability. Diagnosis physical quantities: K, SI, BLI, and total precipitable water content have good indications for early forecasting of severe convective weather; 3) Radar echoes fully reflect the precipitation trend. The whole echo band extends from the southwestern to the northeastern part of southeast Chongqing, forming a long strip shape. It continuously moves from west to east, forming a train effect, resulting in persistent precipitation in southeast Chongqing. The overall accumulated rainfall is large, causing heavy rain to heavy rain in the overlapping region between the northern part of southeast Chongqing and the echo band, which has a good indication for the location of the heavy precipitation center.