副热带高压影响下龙岩夏季对流降水特征研究OA

To better understand the summer convective precipitation characteristics in the Longyan region under the influence of the subtropical high,this study selected the period from July to September each year between 2017 and 2021 when the subtropical high had an impact.Using radar base data,ECthin forecast data,and 6-hourly ERA5 reanalysis data with a resolution of 0.25°×0.25°,the study analyzed the spatiotemporal distribution characteristics of convective precipitation,convective initiation and convective movement tracks under different steering winds in Longyan,as well as the forecast performance of the ECthin model.The results indicate show that:(1)the convective frequency and convective initiation frequency are higher in the eastern part of Longyan than in the western part from July to September,and the peaks for each month are concentrated between the afternoon and before midnight.(2)The main convective influence systems in each month vary under the control of different subtropical high positions.(3)The direction of convective propagation mostly aligns with the direction of the steering winds at 850 hPa.(4)The reliability of various physical quantities predicted by ECthin is high,while the spatial distribution of individual physical quantities corresponds poorly to that of the actual conditions.