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

Xavier Lana,Ricard Kirchner,Raül Rodríguez-Solà,Carina Serra,M Dolors Martínez,M Carmen Casas-Castillo

doi:10.1007/s00704-021-03773-z

Xavier Lana, Ricard Kirchner + Show 4 more

Open Access

https://doi.org/10.1007/s00704-021-03773-z

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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 floods and, conversely, sometimes with long dry spells exceeding 1 month length, depending on the chosen threshold level to define 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 quantified by means of their time trends, statistical significance 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, different 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 effects on the temperature regime, the influence on the pluviometric regime could not be negligible.Graphical abstract

Highlights

The rainfall amounts at monthly and annual scale for Cata‐ lonia (NE Spain) are characterised by quite notable spatial and temporal irregularities
Spain annual extreme drought characteristics, and rainfall shortage characterised by the standardised precipitation index, SPI, have been analysed years ago by Serra et al (1998), Lana and Burgueño (1998), Lana et al (2001, 2004), Martínez et al (2007) and Casas et al (2007), among others. Apart from all these characteristics of the rainfall pat‐ tern, negative time trends on rainfall amounts at monthly and annual scale would be another factor of complexity to design a right use of water resources for agriculture, indus‐ try, drinking water supply or generation of hydroelectric power, for instance
An example of the CO2 effects on the Mediter‐ ranean region could be the reduction of the annual amounts, in agreement with the negative time trends detected in this paper, the increasing of extreme episodes and the persever‐ ance of long drought episodes (Pérez and Boscolo 2010; Miranda et al 2011)

Summary

Introduction

The rainfall amounts at monthly and annual scale for Cata‐ lonia (NE Spain) are characterised by quite notable spatial and temporal irregularities. They are usually consequence of copious episodes of short length, sometimes causing flood events and usually associated with eastern advections or convective phenomena, the closeness to the Western Medi‐ terranean playing a relevant role. Dry spells of notable length are another characteristic of this plu‐ viometric regime Some examples of these complexities and irregularities, which include daily, monthly and annual amounts relationships with surface synoptic circulations,.

Database

Climate characteristics

Conclusions