沿河县近20年低涡切变型暴雨过程研究

Study on Low Vortex Shear Rainstorm Process in Yanhe County in Recent 20 Years

根据2000—2019年的降水资料和MICAPS高空地面资料,选取了12次典型低涡切变型暴雨过程,分析其环流形势和物理量特征。得出结论:过程发生时副高脊线稳定在22°N~27°N之间,高层低槽东移加深、中低层明显的低涡切变、与地面中尺度辐合线的配合是造成低涡切变型暴雨过程发生的主要环流形势;沿河处于西南急流区或左侧、水汽含量大值区,有充足的水汽条件供应;低层气旋性辐合、中高层辐散所造成的抽吸作用进一步加剧了上升运动,上升气流的维持使得降水持续。这些条件对沿河县低涡切变型暴雨的预报有很好的指示作用。

According to the precipitation data from 2000 to 2019 and MICAPS high-altitude ground data, 12 typical low vortex shear rainstorm processes are selected,and their circulation situation and physical quantity characteristics are analyzed. It is concluded that when the process occurs, the subtropical high ridge is stable between 22° N and 27° N, the eastward movement and deepening of the high-rise low trough, the obvious low vortex shear in the middle and low levels, and the coordination with the ground mesoscale convergence line are the main circulation situation causing the low vortex shear rainstorm process;The river is located in the southwest jet area or the left side and the area with high water vapor content, with sufficient water vapor supply;The suction caused by low-level cyclonic convergence and middle and high-level divergence further intensifies the upward movement,and the maintenance of updraft makes the precipitation continue. These conditions have a good indication for the prediction of low vortex shear rainstorm in Yanhe County.