Abstract

۱٫ Introduction

۲٫ Data and methods

۳٫ Results and discussion

۴٫ Conclusions

CRediT authorship contribution statement

Declaration of Competing Interest

Acknowledgments

References

Abstract

     Droughts affect the environment, the economy, and society causing socioeconomic problems derived from water scarcity, and actions are therefore required to mitigate them. To efficiently manage water resources, and prevent and mitigate the consequences of water scarcity, it is important to identify and characterize drought events. A study of the evolution of drought episodes over Galicia (NW Iberian Peninsula) from 1960 to 2020 was conducted based on data from several rain gauges in the region. The standardized precipitation index (SPI) at different time scales was used to characterize drought conditions. The results revealed an increase in the number of periods under drought conditions and the intensity of drought events towards the end of the period analyzed. The events tended to become longer over time, with a clear increase in the worst drought conditions.

Introduction

     Droughts are natural weather events that can potentially have a devastating effect on millions of people worldwide. Drought events can cause damage to agriculture, forestry, and land use by increasing the water consumption of crops and reducing their production. An increase in the occurrence of these episodes could modify the soil conditions producing changes in the geographical distribution of crops or a decrease in agricultural production in the affected areas. This will have important impacts on economic activities, ecosystems, and human health (Alary et al., 2014, Lesk et al., 2016, Stanke et al., 2013).

     Despite their recurrence, droughts are among the most complex and poorly-understood extreme hydrological events (Wilhite, 2000). Drought is rarely predicted accurately and, unlike other natural weather disasters, it begins imperceptibly and goes unnoticed by the population until the damage becomes visible, at which point it is too late to mitigate the negative effects (Wilhite et al., 2007, Below et al., 2007, Bond et al., 2008, Funk, 2011, Wilhite and Pulwarty, 2018). In recent decades, there has been an increase in drought episodes in many regions of the world that has affected various aspects of society (e.g., economic output and demography…), and caused significant losses in agricultural production and health (Barnett, 2011, Briffa et al., 2009, Masih et al., 2014, McGree et al., 2016, Sobral et al., 2018, Xu et al., 2015). Therefore, it is important to understand the dynamics of this type of natural hazard, and to characterize and study these events. This will improve the human capacity to adapt to the problem and mitigate its effects.

Conclusions

     Several studies have shown that the IP experiences recurrent droughts with a predominant trend towards drier conditions in recent decades. Nevertheless, different behaviors have been found among several sub-regions, indicating that the spatial distribution of drought episodes can be very diverse. Opposing signals have been identified in many regions indicating that local studies can contribute to a better characterization of drought events throughout the IP.

     This study investigated drought evolution in Galicia over a 60 year period (1960–۲۰۲۰) using data from a dense network of 23 stations located throughout the area in an attempt to improve the understanding of regional drought. Galicia is located in a transition zone between different types of air masses, and therefore the conclusions of studies of climatic variations, such as drought events, carried out for other areas of the IP, such as the Mediterranean, cannot be directly extrapolated to this area. An individualized study is required for this region.