Rainfall regime trends at annual and monthly scales in Catalonia (NE Spain) and indications of CO2 emissions effects

Abstract

The pluviometric regime in the Western Mediterranean and concretely in Catalonia (NE Spain) is characterised by irregular amounts at monthly and annual scales, sometimes with copious short episodes causing foods and, conversely, sometimes with long dry spells exceeding 1 month length, depending on the chosen threshold level to defne the dry episode. Taking advantage of a dense network of rain gauges, most of them with records length of 50–60 years and some others exceeding 85 years, the evolution of these monthly and annual amounts is quantifed by means of their time trends, statistical signif- cance and several irregularity parameters. In agreement with the evolution of the CO2 emissions into the atmosphere and the increasing concentration, in parts per million (ppm), of this greenhouse gas, diferent time trends at annual scale have been detected up to approximately years 1960–1970 in comparison with the interval 1960–1970 to nowadays. Consequently, besides the greenhouse efects on the temperature regime, the infuence on the pluviometric regime could not be negligible. ; Rainfall data have been supplied by Servei Mete‑ orològic de Catalunya (Generalitat de Catalunya), Fabra Observatory (RACA, Barcelona) and Ebro Observatory (Ramón Llull University and CSIC, Spanish Government). This research was supported by the Spanish Ministry of Science, Innovation and Universities: grant 460 number PID2019-105976RB-I00] and grant number AGL201787658-R. The authors also thank the editor and the anonymous reviewers for their valuable comments and suggestions to improve the manuscript ; Peer Reviewed ; Postprint (published version)