珠三角一次春季强对流过程的数值模拟研究

Numerical Simulation of a Spring Rainstorm in Pearl River Delta

春季华南地区由于冷空气减弱,西南气流逐渐加强,经常发生强对流和暴雨天气。为进一步研究华南地区春季暴雨的发生机制,并提高预报的准确性,使用中尺度数值模式WRF对2014年3月30—31日发生在珠三角地区的一次春季强对流天气过程进行2 d的积分模拟,将数值模拟输出的高分辨资料结合温度、风廓线雷达资料进行中尺度分析。结果表明:本次过程中低空急流的建立和维持促进了低层辐合,并为强对流区提供了充足的水汽及能量;边界层垂直风切变、强烈的上升运动均有利于冰雹等强对流天气发生。

In spring,due to the weakening of cold air in South China,the southwest airflow gradually strengthens,and strong convection and rainstorm often occur.In order to further study the mechanism of spring rainstorm in South China,and improve the accuracy of the forecast,this paper used the mesoscale numerical model WRF to carry out integral simulation of a spring rainstorm occurred in Pearl River Delta from March 30th,2014 to 31st for 2 d.The highresolution data from numerical simulations was combined with temperature and wind profile radar data to conduct the mesoscale analysis.The results showed that establishment and maintenance of low-level jets promoted low-level convergence,and provided sufficient aqueous vapour and energy for strong convection areas.The vertical wind shear and strong ascending motion of the boundary layer were favorable to the severe convection weather.