CHANGES IN COMBINED EFFECT OF EXTREMES BASED ON MODIFIED CLIMATE EXTREMES INDEX (mCEI) OVER THE EUROPE-MEDITERRANEAN REGION

Abstract

<p>Multiple climate extremes have diverse impacts on the human environment and the natural ecosystem. The use of a compact set of climate change indices enhances our understanding of the combined impacts of extreme climatic conditions. In this study, we calculated percentile based extreme temperature and precipitation indices, and self-calibrating Palmer Drought Severity Index over the Europe-Mediterranean (EURO-MED) region for 1979-2016 period. Moreover, we extended the Climate Extremes Index (CEI) as the modified Climate Extremes Index (mCEI) to obtain combined information regarding the extremes on the grid basis. As a holistic approach mCEI provides detailed spatiotemporal information on annual timescale, and high-resolution grid-based data allows us to do detailed country-based and city-based analyses. For temperature, we use the last generation ERA5 reanalysis dataset, and for precipitation, we use MSWEP gridded observational dataset. The results indicate that warm temperature extremes are significantly on the rise over the EURO-MED region whereas the cold temperature extremes decrease. The extreme drought has a significant increasing trend. Although there are heterogeneous regional distributions, extreme precipitation indices have a significant increasing tendency. Additionally, we found that the Mediterranean coasts, the Balkan countries, the Eastern Europe, Iceland, the parts of western Russia, the parts of Turkey, and the parts of Syria and Iraq are the major hot-spots for the combined extremes based on mCEI. Among the major urban agglomerations of the EURO-MED region, 28 cities exhibit a significant increasing trend of the mCEI greater than 1.5% decade<sup>-1</sup>. These results agree with the previous findings related to the climatic extremes of the EURO-MED climate hotspot, and strengthen the findings on human-induced climate change.</p>