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Arid Land Geography ›› 2023, Vol. 46 ›› Issue (9): 1407-1417.doi: 10.12118/j.issn.1000-6060.2022.567

• Climatology and Hydrology • Previous Articles     Next Articles

Probability distribution and comprehensive risk assessment of extreme precipitation in flood season in Shaanxi Province

SHI Weiliang(),CHE Luyang(),LI Tao   

  1. School of Statistics, Xi’an University of Finance and Economics, Xi’an 710100, Shaanxi, China
  • Received:2022-11-02 Revised:2023-01-06 Online:2023-09-25 Published:2023-09-28

Abstract:

Rainstorms and the resulted floods represent the second most important type of natural disaster in the Shaanxi Province of China. To clearly describe the risk arising from extreme precipitation events, extreme precipitation amount, frequency, and intensity series were constructed using 1969—2020 flood season (May-October) daily precipitation data for Shaanxi Province. Six extreme-value probability distribution models were selected to fit the constructed series to obtain the optimal probability distribution model for flood season extreme precipitation and to evaluate the future trend of extreme precipitation events in Shaanxi Province. The comprehensive risk of extreme precipitation was evaluated based on spatial risk distributions of different scenarios in Shaanxi Province. The results showed that: (1) Through error analysis and comparison, the Wakeby probability distribution was found to be the optimal model for fitting the sequence of extreme precipitation indicators during the flood season in Shaanxi Province, accounting for the largest proportion of extreme values in the three constructed series. (2) Extreme precipitation values with different return periods were calculated and compared with existing maximum precipitation values. An increased probability of low-probability and high-risk extreme precipitation events was found for most areas of Shaanxi Province. (3) The comprehensive risk of extreme precipitation during the flood season was found to be generally high in the south and low in the north of Shaanxi Province. Risk areas differed between scenarios of 2-, 5-, 10-, 20-, 50-, and 100-year return periods. With increasing return periods, the low-risk area gradually reduced and the high-risk area gradually increased. In the 100-year return period scenario, the high-risk area increased from 0 to 22.0%. The study provides a reference for the investigation of extreme precipitation probability distributions in Shaanxi Province and provides a theoretical basis for extreme precipitation risk management and assessment during flood seasons.

Key words: extreme precipitation, probability distribution, hazard analysis, risk assessment, Shaanxi Province