Spatial Heterogeneity in the Occurrence Probability of Rainstorms over China

Yan-Fang Sang

doi:10.3390/e20120958

Abstract

Detecting the spatial heterogeneity in the potential occurrence probability of water disasters is a foremost and critical issue for the prevention and mitigation of water disasters. However, it is also a challenging task due to the lack of effective approaches. In the article, the entropy index was employed and those daily rainfall data at 520 stations were used to investigate the occurrences of rainstorms in China. Results indicated that the entropy results were mainly determined by statistical characters (mean value and standard deviation) of rainfall data, and can categorically describe the spatial heterogeneity in the occurrence of rainstorms by considering both their occurrence frequencies and magnitudes. Smaller entropy values mean that rainstorm events with bigger magnitudes were more likely to occur. Moreover, the spatial distribution of entropy values kept a good relationship with the hydroclimate conditions, described by the aridity index. In China, rainstorms are more to likely occur in the Pearl River basin, Southeast River basin, lower-reach of the Yangtze River basin, Huai River basin, and southwest corner of China. In summary, the entropy index can be an effective alternative for quantifying the potential occurrence probability of rainstorms. Four thresholds of entropy value were given to distinguish the occurrence frequency of rainstorms as five levels: very high, high, mid, low and very low, which can be a helpful reference for the study of daily rainstorms in other basins and regions.

Highlights

Water disasters, triggered by rainstorms, have been becoming a major type of natural hazard worldwide [1,2], and have received extensive attention in recent times
The results are determined by statistical characters of rainfall data and closely related to the hydroclimate entropy results are determined by statistical characters of rainfall data and closely related to the hydroclimate conditions, and can intuitively reflect the spatial heterogeneity in the occurrence probability of rainstorms over China
It is concluded that the entropy index can be an effective alternative for indicating the potential occurrence probability of rainstorms

Summary

Introduction

Water disasters, triggered by rainstorms, have been becoming a major type of natural hazard worldwide [1,2], and have received extensive attention in recent times. Due to obvious spatial heterogeneity in the geographic and hydroclimate conditions, the occurrence frequencies of rainstorms and water disasters and their magnitudes vary with regions in. Many indices have been proposed and used to quantify the potential occurrence probability of water disasters, whose intensity, frequency and duration are usually considered together [7,8]. Each index can only describe certain characteristics of water disasters, and the values of various indices usually have different spatial distributions [10], causing confusion of the spatial heterogeneity in the occurrence probability of water disasters. The main objective is to explore whether the index of entropy can be an effective measure for quantifying the spatial heterogeneity in the occurrence probability of rainstorms, as an important indicator of water disasters

Data and Methods

Results and Discussion

Relationship

4.4.Conclusions

Conclusions