A spatiotemporal analysis of precipitation anomalies using rainfall Gini index between 1980 and 2022

Abstract

As a reaction to the expanding challenges associated with social susceptibility and their interconnection to diverse environmental threats, parametric insurance plays a key role as an innovation tool in the insurance sector to enhance social resilience to natural disasters and extreme climatic conditions, which can tremendously impact several economic sectors, including agriculture and as a result food security. In this context, this research investigates the association between rainfall Gini index and drought events in Western Europe. For this purpose, we acquired ERA5 data for daily precipitation for five locations from 1980 to 2022. Gini index (GI) values were calculated and analyzed for each location with the Mann–Kendall test at a 5% significance level. As expected, a minimal decreasing trend has been observed for daily precipitation, while an increasing trend was recorded for Gini index. In addition, data on the soil moisture index (SMI) and top drought events were extracted from the European Drought Observatory (EDO) to explore their potential connection with the Gini index over time and space. Although a moderately low to negligible correlation, ranging between −0.27 and 0.02, was found between SMI and GI, a qualitative comparison between major drought episodes and Gini index anomaly showed that similar spatiotemporal patterns are present across the region, particularly for extreme drought events in 1996–1997 and 2003. The current study elucidates the rainfall Gini index's efficiency as a drought indicator for qualitative analysis, yet more work must be conducted to quantitatively evaluate its association with drought magnitude.