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Arid Land Geography ›› 2023, Vol. 46 ›› Issue (9): 1443-1452.doi: 10.12118/j.issn.1000-6060.2022.659

• Climatology and Hydrology • Previous Articles     Next Articles

Fine meteorological risk early warning forecast of main geological disasters in Gansu Province

ZHANG Junxia1(),HUANG Wubin1(),LI Antai2,YANG Xiumei1,LI Qian1,BIAN Hongwei2   

  1. 1. Lanzhou Central Meteorological Observatory, Lanzhou 730000, Gansu, China
    2. Lanzhou Dafang Electronics Co. Ltd., Lanzhou 730000, Gansu, China
  • Received:2022-12-13 Revised:2023-03-31 Online:2023-09-25 Published:2023-09-28

Abstract:

Geological disasters frequently occur in Gansu Province, China, and the proportion of precipitation-type geological disasters is significant in this region. Based on the geological disaster data, encrypted precipitation observations and the CMA multi-source merged precipitation analysis system pertinent to April to October of each year from 2013 to 2021 in Gansu Province, the effective rainfall data were selected as the precipitation factor; and further the geological disaster probability fitting equations of effective rainfall for the two regions were established. A refined grid geological disaster meteorological risk early warning model is constructed using the disaster probability of the precipitation factor, potential risk of geological disaster, and vulnerability. Using real precipitation data and the fine gridded prediction forecasts (QPF) of the Lanzhou Central Meteorological Observatory, a mesh refinement forecast test of the risk model was established to test the geological disaster events that occurred in October 2021 in Gansu Province. The study results show the following: (1) Based on the disaster probability caused by effective rainfall, the critical effective rainfall thresholds of blue, yellow, orange, and red warning levels of geological disasters in the Loess Plateau and Longnan Mountains, respectively. Among them, the critical effective rainfall thresholds for blue and red warning levels in Longnan Mountains are 40.6 mm and 113.5 mm, respectively, which were significantly higher than the blue and red warning levels of 18.0 mm and 73.6 mm, respectively, in the Loess Plateau. (2) The risk discrimination indices of blue, yellow, orange, and red early warning levels of geological disaster meteorological risk in Gansu Province were determined. The index values ranged from 0.004 to 1.000, with values ranging from 0.336 to 1.000, indicating an early red warning level. (3) The refined grid geological disaster meteorological risk early warning model in Gansu Province can effectively provide a warning of geological disaster events, the proportion of each level of early warning is reasonable, and it can effectively reduce the high-level early warning rate and false alarm rate. Thus, the model shows a strong ability to provide geological disaster meteorological risk early warnings.

Key words: geological disaster, meteorological risk, effective rainfall, disaster probability caused by effective rainfall, Gansu Province