Abstract: In recent years, extreme precipitation events have become increasingly frequent in Shandong Province. To improve the monitoring, forecasting, and early warning of these short-duration events, this study analyzes minute-level precipitation data from 99 national meteorological stations in Shandong Province, covering the period from 1991 to 2020. Using the climate tendency rate, wavelet analysis, and empirical orthogonal function decomposition, we examine the spatiotemporal distribution and variability of annual maximum precipitation across different short durations. The results indicate that both the average and maximum values of annual maximum precipitation for all short durations increase progressively from central and eastern Shandong outward, peaking in southern Shandong. In most parts of southern Shandong, these annual maxima show a decreasing trend over time, whereas most other areas exhibit an increasing trend. For 5-min durations, the spatial variability trends are generally consistent, with intensity centers located in northwestern Shandong. For the 30-min and 60-min durations, eastern and southern Shandong, as well as the eastern Shandong Peninsula, show trends opposite to those in other regions, with negative intensity centers in central-western, northwestern, and southwestern Shandong. For the 90-min, 120-min, and 180-min durations, the eastern central region and the eastern Shandong Peninsula display opposite trends, with positive intensity centers in southwestern Shandong. Each duration shows significant 2–3 year periodicities. An abrupt change was detected in 2004 for the 5-min duration, leading to a marked decrease thereafter, whereas no abrupt changes were observed for other durations. Overall, most annual maximum short-duration precipitation events in Shandong exhibit an increasing trend. These findings underscore the importance of enhancing monitoring efforts and revising storm intensity formulas, particularly in southern and northwestern Shandong.

Key words: Shandong Province, short duration, annual maximum precipitation, spatiotemporal variability