Comparative Analysis of Rainstorm Triggering Conditions at the Northern and Sorthern Piedmont of the Qinling Mountains
A heavy rainstorm process occurring simultaneously at the northern and southern piedmont of the Qin-ling Mountains from August 21 to 22,2021 is compared and analyzed to explore the influence mechanism of the triggering conditions at the northern and sorthern piedmont of the Qinling Mountains by using the real-time mete-orological observation data,FY-2G satellite cloud images,doppler radar data and ERA5 0.25°x0.25° hourly re-analysis data.The result shows that on the flow field of the northern piedmont of the Qinling Mountains,the westerly system forms a meso-scale cyclonic circulation in the lower troposphere under the special topography of the Qinling Mountains,which triggers heavy rainfall through thermal effects.Convective precipitation is short-lived and its intensity is weak.The enhancement of wet baroclinicity is a signal of the beginning of the rainstorm at the northern Qinling Mountains.The precipitation ends when the wet baroclinicity weakens and the specific hu-midity of the middle layer decreases.For the southern piedmont of the Qinling Mountains,the formation of me-soscale convergence lines in the lower tropospheric flow field under the effect of topography triggers the rain-storm.The condensation latent heat released by precipitation heats the lower atmosphere and establishes a convec-tive instable structure,together with the cold intrusion in the middle and lower layers,which leads to the en-hancement of the upward movement and the precipitation.Under the high temperature and humidity environ-ment,the convective cloud organizes and develops rapidly to form the MCC,which has a high convective inten-sity,deep convective tropospheric junctions,and powerful hourly rainfall.The timing of the invasion and diffu-sion of cold air in the lower and middle layers to the ground represent the beginning and end of heavy rain at the sorthern Piedmont of the Qinling Mountains respectively.
the Qinling Mountains terrainrainstormdynamic effectthermal action
万方数据
维普
