Observation and Analysis of Two Heavy Rainfall Events Using X-Band Phased Array Weather Rada
WANG Xuejing
HUANG Xingyou
MA Shuqing
Abstract：Heavy rainfall prediction is challenging because different trigger mechanisms and atmospheric conditions lead to different evolution processes.Based on X-band phased array antenna weather radar(XPAR)data and S-band dual-polarization Doppler weather radar(SPOL)data,this paper compares two local heavy rainfall events that occurred in Wuhu on June 5,2022,and in Shanghai on June 29,2022 to explore the spatial variations of reflectivity factor and wind field during the development of the two heavy rainfall processes,with an emphasis on the convective evolution of the Shanghai storm.The results show that:(1)The heavy rainfall in Wuhu occurred under a cold-frontal weather background,triggered by the southward-moving cold front and the low-level shear line,which was a weak cold front rainstorm.In contrast,the short-term heavy rainfall in Shanghai was a rainstorm process within the warmsector.It resulted from a weak synoptic-scale disturbance,where shallow cold air intrusion from thesurface interacted with warm-moist air to form a mesoscale convergence belt,thereby triggering theconvection.(2)During Wuhu rainfall,a small-scale meridional vertical circulation in the warm-moist air ahead of the cold front provided updrafts for the heavy rainfall.During the process of convective rainfall in Shanghai,due to the intrusion of shallow cold air near the surface air and the cold outflow of the thunderstorm,new cells were triggered intermittently by the northernly air in front of the thunderstorm.(3)The weak cold front type of rainstorm system in Wuhu was stable,varies slowly,with no obvious cell initiation or merging,so the rainstorm development is easy to predict.As for the local warm sector heavy rainfall in Shanghai,it is difficult to forecast the development because of its small scale,strong convection,rapid evolution with new convective cell initiation,merging and dissipation.
Keywords：cold-front heavy rainwarm sector heavy rainfallXPARmeso-small scale structurethree-di-mensional wind field
Publication Date：2025-08-30
Online Publishing Date：2025-09-23(First online date of this platform, not the publication date of the document)
Pages：13( 553-565 )