Multi-annual drought episodes in the Mediterranean (Valencia region) from 1950-1996. A spatio-temporal analysis

Abstract

ABSTRACTIn the early 1990s, the Valencia region suffered a severe drought episode that led the scientific community to suspectthat the Iberian Peninsula was heading towards generalized desertification. However, an analysis of the last 40 yearsshows that the Valencia region has experienced several drought episodes of different intensities, but always withimportant economic and social consequences. This paper studies the episodes occurring since 1950, with regard totheir intensity, duration and spatial distribution. By using recurrence analysis, four such episodes have been identified:1952–1955, 1963–1964, 1978–1985, 1993–1995. Despite Valencia being a relatively small region, intra-regionalvariations in the intensity and spatial and temporal distribution of drought episodes can be observed. Copyright© 2000 Royal Meteorological Society. KEY WORDS :drought; probability of recurrence; rainfall temporal analysis; Valencia region; western Mediterranean basin 1. INTRODUCTIONIn the early 1990s, the southern half of the Iberian Peninsula was affected by a drought episode. Thoughits intensity was not uniform throughout the area, its pronounced negative impact on local agriculture,together with a growing preoccupation in the scientific community and the media with the concept ofGlobal Change, led many to believe that this drought was one more step in a generalized process ofdesertification in the Iberian Peninsula. However, no detailed studies exist that prove or disprove thisassertion.In fact, in the context of a Mediterranean climate, one must be very cautious about advancingconclusions on climatic change, especially on a global scale. It is well known that one of the most notablecharacteristics of this type of climate is the great variability in annual and multi-annual rainfalls. It shouldbe recalled that most of the regions in the Mediterranean basin have suffered extreme climaticphenomena, which have partly conditioned human activities. Torrential rainfalls and periods of droughthave had the most important impacts, either because of their persistence or because of their catastrophiccharacter. There are few studies on the historical climatology of the Valencia region. Most of them arerelated to the analysis of flood events (Barriendos, 1994), but there are no systematic studies related todrought episodes during recent centuries at a regional level. Nevertheless, there are some studies onintense drought periods in Catalun˜a, a region north of Valencia (i.e. the period 1812–1824) (Marti´n Videand Barriendos, 1995; Barriendos and Dannecker, 1999).In the last 40 years, the Iberian Peninsula (and especially the southeastern part) has experiencedextended periods of below normal rainfall. Garci´a Merayo