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| DOI：10.13522/j.cnki.ggps.2026050 |
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| Spatiotemporal variation of regional rainstorms and their driving factors in Shandong Province |
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Ren Yinuo, Lu Xiaoning, Ren Jiancheng, He Min
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1. College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, China;
2. Binzhou Meteorological Bureau, Binzhou 256612, China
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| Abstract: |
| 【Objective】Rainstorms are prominent meteorological risks. Understanding their spatiotemporal variation and driving factors in a region is critical to developing mitigation strategies. This study analyses the spatiotemporal variation of regional rainstorms in Shandong Province and their determinants.【Method】The study was based on daily precipitation data measured from 109 meteorological stations from 1978 to 2020 across the province. The province was divided into five meteorological-geographical subregions. Empirical orthogonal function (EOF) decomposition, North significance test and climatic statistical analysis, combined with the self-established comprehensive rainstorm intensity index and percentile classification method, were used to analyse the spatiotemporal variation of its key driving factors.【Result】①EOF decomposition identified three significant spatial patterns of annual rainstorm days in the province, with a cumulative variance contribution rate of 39.34%. These three patterns are: provincially consistent pattern, southeast-northwest reverse pattern, and central-sides reverse pattern. The five subregions showed distinct spatiotemporal variation in each pattern. The south and centre of the province were highly rainstorm-sensitive areas, while rainstorms in the northwest and north showed dramatic fluctuations, jointly controlled by monsoon circulation and regional topography. ②A total of 386 regional rainstorm events were recorded from 1978 to 2020 across the province, with an average of 8.9 events per year. The overall rainstorm frequency showed a slight decreasing trend from 1978 to 2020, though not at significant level, accompanied by noticeable interannual and interdecadal fluctuations. In total, 65.8% of rainstorm events occurred in July and August. ③Most regional rainstorms were short event, with an average duration of 1.5 days; 94% of rainstorm events lasted 1-2 days. On average, each rainstorm event affected 23 meteorological stations. ④Analysis using the comprehensive intensity index constructed from the rainstorm duration, their affected area, and rainfall intensity showed that regional rainstorm events can be divided into four grades.【Conclusion】Three dominant spatial patterns of rainstorms were identified in Shandong Province, which were affected by atmospheric circulation and topography. The findings unveil the spatiotemporal heterogeneity of regional rainstorms and can help develop strategies to mitigate the adverse impacts of regional rainstorms in Shandong Province. |
| Key words: Shandong Province; regional rainstorm; EOF decomposition; spatiotemporal distribution characteristics; quantitative assessment |
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