Assessment of centennial (1918–2019) drought features in the Campania region by historical in situ measurements

Abstract

Abstract. Drought is a sustained period of below‐normal water availability. It is a recurring and worldwide phenomenon, but the Mediterranean basin is seen as a very vulnerable environment in this perspective and understanding historical drought conditions in this area is necessary to plan mitigation strategies to further face future climate change impacts. The reported research was aimed at the description of drought conditions and evolution for the Campania region (Southern Italy), assessed by the analysis of an in-situ measurement database which covers a centennial period from 1918–2019. SPI time series were reconstructed for different accumulation time scales (from 3 to 48 months) and the Modified Man Kendall and Sen s test were applied to identify SPI changes over time. SPI time series were mostly affected by a negative trend, significant for a very large area of the region, particularly evident for the accumulation scales larger than 12 months. Mean drought duration (MDD), severity (MDS) and peak (MDP) were furthermore investigated for both moderate (SPI\u2009≤\u2009−1) and extremely severe conditions (SPI\u2009≤\u2009−2). The accumulation scale affected the drought features, with longer duration and larger severity associated to the larger accumulation scales. Drought characteristics spatial patterns were not congruent for the different SPI time scales: if duration and severity were larger in the southern areas, peaks appeared mostly severe in the northern areas of the region. Extremely severe events were featured by lower durations and larger severity compared to the moderate drought events but were very less frequent (over 75\u2009% less then) and did not appeared to be focused on specific areas of the region.