增强副热带高压对西南涡影响的数值试验

本文通过对伴随副热带高压(简称副高)东退而东移的一次典型西南涡天气过程(简称20150721过程)进行数值模拟,采用数值敏感性对比试验探讨了增大副高强度对这次东移西南涡的影响,得到以下结论:(1)副高强度增大以后,可长时间稳定维持,能对西南涡中尺度天气系统整个发展演变过程造成持续影响.西南涡路径和强度的变化直接...

Simulation of Effect of Subtropical High Enhancement on Southwest Vortex

Based on regional model simulations of a typical case of an eastward-moving Southwest vortex with the eastern retreat of a subtropical high (case 20150721), this paper discusses the effect of the strength of the subtropical high on the eastward Southwest vortex based on a numerical sensitivity test of a subtropical high enhancement. The main results are as follows: (1) An enhanced subtropical high can be stably maintained for a long time and can have a lasting impact on the development and evolution of the entire Southwest vortex meso-scale system. The area and intensity of precipitation directly depends on the path and intensity of the Southwest vortex. (2) The circulation field first changes when the strength of the subtropical high increases, the invading north wind becomes weaker, and the southwest guided airflow becomes stronger, which eventually results in a faster and weaker Southwest vortex. (3) The change in the circulation field directly affects the transport, convergence, and divergence of the water vapor, and further affects the whole evolutionary process of the Southwest vortex. (4) After the increase in the subtropical high, the faster Southwest vortex results in the deviation between the center of the Southeast vortex and the thermal center in the lower layer, which causes a mismatch between the dynamic and thermal centers and a weakening of the strength of the Southwest vortex.