陕西关中西部短时强降水时空特征及其与地形的关系OA

Investigating the spatiotemporal characteristics of short-time heavy rainfall and its relationship with to-pography is crucial for developing regionally refined nowcasting models and enhancing risk assessment and pre-vention capabilities for extreme precipitation disasters.The spatiotemporal distribution of short-time heavy rain-fall in western Guanzhong was analyzed using hourly precipitation data from 327 meteorological stations during the warm season(April-September)from 2018 to 2024,ERA5 reanalysis data from the European Centre for Me-dium-Range Weather Forecasts,and 30 m digital elevation model data.The controlling roles of topography were investigated using inverse distance weighting,principal component analysis,and linear regression.The results in-dicate the following:(1)The frequency of short-time heavy rainfall events during the warm season increased be-tween 2018 and 2024.The rainfall intensity predominantly ranged from 20 to 40 mm·h-1.The majority of events occurred between mid-July and early August,and the maximum recorded rainfall intensity exceeded 50 mm·h-1.The diurnal variation was bimodal,with the most active period between 18:00 and 23:00.(2)The spatial distribu-tion was uneven:high-frequency rainfall areas were located in the northern high-altitude loess tableland and the northern foothills of the western Qinling Mountains,and low-frequency rainfall areas were located in the eastern low-altitude plains.Significant diurnal variation was observed.During the daytime,high-frequency areas were scattered primarily north of the Weihe River,whereas during the night they were concentrated on the northern loess tableland.(3)The frequency of the short-time heavy rainfall was significantly correlated with elevation,lati-tude,and longitude,with elevation the most dominant factor.Topographic thermal uplift played a secondary role,and dynamic lifting had the least influence.The short-time heavy rainfall showed a single-peak pattern with alti-tude,with most events occurring at altitudes between 400 and 1300 m.The frequency of short-time heavy rainfall above 1300 m decreased with increasing altitude.These findings provide a theoretical foundation for improving forecasting and the early warning of short-time heavy rainfall in the region.