Modeling drought impact occurrence based on meteorological drought indices in Europe

• Published in: Journal of hydrology (Amsterdam) 2015-11, Vol.530, p.37-50
• Main Authors: Stagge, James H., Kohn, Irene, Tallaksen, Lena M., Stahl, Kerstin
• Format: Article
• Language: English
• Subjects: Anomalies; Drought impacts; Droughts; Ecosystems; Europe; Freshwater; Freshwaters; Links; Logistic regression; Mathematical models; Meteorological drought; Regression; SPEI; SPI; Water supplies
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2015.09.039

•Empirical models directly link impacts with meteorological drought indicators.•User-reported impacts cover four categories and five European countries.•The most relevant drought index and periods differ among regions and impacts.•Differences in predictors are related to hydrologic differences and management.•Models have good predictive skill, with high pseudo-R2 and selective ROC curves. There is a vital need for research that links meteorological drought indices with drought impacts felt on the ground. Previously, this link has been estimated based on experience or defined based on very narrow impact measures. This study expands on earlier work by showing the feasibility of relating user-provided impact reports with meteorological drought indices, the Standardized Precipitation Index and the Standardized Precipitation-Evapotranspiration Index, through logistic regression, while controlling for seasonal and interannual effects. Analysis includes four impact types, spanning agriculture, energy and industry, public water supply, and freshwater ecosystem across five European countries. Statistically significant climate indices are retained as predictors using step-wise regression and used to compare the most relevant drought indices and accumulation periods across different impact types and regions. Agricultural impacts are explained by 2–12month anomalies, though anomalies greater than 3months are likely related to agricultural management practices. Energy and industrial impacts, typically related to hydropower and energy cooling water, respond slower (6–12months). Public water supply and freshwater ecosystem impacts are explained by a more complex combination of short (1–3month) and seasonal (6–12month) anomalies. The resulting drought impact models have both good model fit (pseudo-R2=0.225–0.716) and predictive ability, highlighting the feasibility of using such models to predict drought impact likelihood based on meteorological drought indices.