Risk zoning of hail disaster in Anhui Province based on terrain correction technology

Terrain correction is a key step to ensure the accuracy of risk zoning for hail disasters. This study utilizes the hail observations from 81 national meteorological stations in Anhui Province spanning from 1978 to 2020, along with geographic information data, gross domestic product (GDP), and historical disaster data, to identify causative factors for hail disasters and calculate the hazard-inducing intensity indices by employing statistical methods of correlation analysis and regression analysis. Then, a terrain-involved correction method for hail frequency is established, with the combination of hazard-inducing intensity and frequency, to conduct disaster risk evaluation. According to the theory of natural disaster risk assessment, the Geographic Information System-based economic risk zonation of hail disaster is performed by integrating the hazard-inducing factors and vulnerability factors. The feasibility of zoning results is further verified through the direct economic losses caused by hail disasters. The results show that: (1) the maximum hail diameter and duration of hailfall can be used as hail hazard-inducing factors, as both are significantly correlated with the damage index of hail disaster. The terrain-corrected spatial distributions of hail frequency are well consistent with the actual observations, which better represent spatial distribution variations in high-altitude mountainous areas. (2) the hail-prone areas, as well as the high-risk areas, are located in several regions along the main paths of hail disaster, such as to the north of the Huaihe River, in the eastern regions between the Yangtze River and Huai River, as well as in the mountainous areas of Dabie Mountains and the south part in Anhui Province. (3) The overall economic risk of hail disasters gradually decreases from north to south. The validation by direct economic losses suggests that the correlation coefficient between the economic risk index of hail disaster and the average of direct economic losses over multiple years in Anhui province has passed the significance test with a confidence level of 99%, and the zoning results agree well with the true situations.