Variation characteristics of summer short duration precipitation in Tianjin during the period of 2004-2023

This study conducts a detailed analysis of short-duration (1-6 h) summer precipitation in Tianjin City based on hourly precipitation data from 13 national-level meteorological observation stations from 2004 to 2023.The results show that short-duration summer precipitation in Tianjin City exhibits apparent spatial variations,generally showing a distribution of more in the northeast and less in the southwest.The cumulative precipitation,precipitation frequency and precipitation intensity in summer of Tianjin City fluctuated greatly within one day,showing obvious V-shaped characteristics from 00:00 to 23:00,with the least precipitation at 10:00.From 2004 to 2023,the summer short-duration precipitation (3.93 mm·a^-1,P<0.01) and process precipitation intensity (0.05 mm·h^-1·a^-1,P<0.001) in Tianjin showed significant increasing trends,while the cumulative precipitation time showed a weak but not significant increasing trend (0.24 h·a^-1,P>0.05).The increase of summer short duration precipitation in Tianjin from 2004 to 2023 is tightly related to the increase of precipitation intensity.