Long‐term variability and trends in meteorological droughts in Western Europe (1851–2018)

• Published in: International journal of climatology 2021-01, Vol.41 (S1), p.E690-E717
• Main Authors: Vicente‐Serrano, Sergio M., Domínguez‐Castro, Fernando, Murphy, Conor, Hannaford, Jamie, Reig, Fergus, Peña‐Angulo, Dhais, Tramblay, Yves, Trigo, Ricardo M., Mac Donald, Neil, Luna, M. Yolanda, Mc Carthy, Mark, Van der Schrier, Gerard, Turco, Marco, Camuffo, Dario, Noguera, Ivan, García‐Herrera, Ricardo, Becherini, Francesca, Della Valle, Antonio, Tomas‐Burguera, Miquel, El Kenawy, Ahmed
• Format: Article
• Language: English
• Subjects: Climate change; Drought; Drought conditions; Drought index; Drought trends; Earth Sciences; Hydrologic data; instrumental period; Mediterranean; Meteorology; Precipitation; Precipitation data; Records; Regional analysis; Regional climates; Sciences of the Universe; Standardized Precipitation Index; Stations; Statistical analysis; Temporal variability; Temporal variations; Trends; Variability; Western Europe
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.6719

We analysed long‐term variability and trends in meteorological droughts across Western Europe using the Standardized Precipitation Index (SPI). Precipitation data from 199 stations spanning the period 1851–2018 were employed, following homogenisation, to derive SPI‐3 and SPI‐12 series for each station, together with indices on drought duration and severity. Results reveal a general absence of statistically significant long‐term trends in the study domain, with the exception of significant trends at some stations, generally covering short periods. The largest decreasing trends in SPI‐3 (i.e., increasing drought conditions) were found for summer in the British and Irish Isles. In general, drought episodes experienced in the last two or three decades have precedents during the last 170·years, emphasizing the importance of long records for assessing change. The main characteristic of drought variability in Western Europe is its strong spatial diversity, with regions exhibiting a homogeneous temporal evolution. Notably, the temporal variability of drought in Western Europe is more dominant than long‐term trends. This suggests that long‐term drought trends cannot be confirmed in Western Europe using precipitation records alone. This study provides a long‐term regional assessment of drought variability in Western Europe, which can contribute to better understanding of regional climate change during the past two centuries. Spatial distribution of (a) the magnitude of change in annual SPI series (December SPI‐12) and (b) their statistical significance. The magnitude of change is expressed in z units/decade.