Spatio-temporal patterns of meteorological droughts in the Balearic Islands (Spain)

Abstract

The Balearic Islands is a region highly prone to suffer meteorological and hydrological droughts, mainly due to the high intra- and inter-annual variability of precipitation, and the high water consumption associated to summer touristic pressure. In this work we aim to characterize the spatial and temporal characteristics of meteorological droughts in the region using a high-density precipitation database for the three main islands. The “Standardized Precipitation Index – SPI” was calculated for each of the 50 precipitation series at the temporal scale of 12 months, which enabled pinpointing in time and space the main drought episodes from 1974 to 2014. Moreover, a Principal Component Analysis performed over the 50 12-month SPI series allowed us to identify two main patterns of drought variability, with a clear spatial distribution. The occurrence of droughts in the northern sector – including the Tramuntana mountain range (Majorca) and Minorca Island – was contrasted and independent to the occurrence of droughts in the southern areas. Similarly, the duration of droughts shows a decreasing trend for the northern region, and a slight increase for the southern stations. Two great drought episodes were identified, with a contrasted spatial propagation: The one in 1988-1991 affected mainly the northern region whereas in the south moist conditions prevailed; and the one occurred in 1999-2001, which affected the whole region but started its propagation from the south, and ended with extreme drought conditions in the eastern part of the territory. Results obtained highlight the need for studies of high spatial resolution in order to accurately assess the spatiotemporal patterns of meteorological droughts.

Keywords

• mediterranean region, meteorological drought, standardized precipitation index (spi), principal components analysis