Santiago Beguería

A New Global 0.5° Gridded Dataset (1901–2006) of a Multiscalar Drought Index: Comparison with Current Drought Index Datasets Based on the Palmer Drought Severity Index

Abstract A monthly global dataset of a multiscalar drought index is presented and compared in terms of spatial and temporal variability with the existing continental and global drought datasets based on the Palmer drought severity index (PDSI). The presented dataset is based on the standardized precipitation evapotranspiration index (SPEI). The index was obtained using the Climatic Research Unit (CRU) TS3.0 dataset at a spatial resolution of 0.5°. The advantages of the new dataset are that (i) it improves the spatial resolution of the unique global drought dataset at a global scale; (ii) it is spatially and temporally comparable to other datasets, given the probabilistic nature of the SPEI; and, in particular, (iii) it enables the identification of various drought types, given the multiscalar character of the SPEI. The dataset is freely available on the Web page of the Spanish National Research Council (CSIC) in three different formats [network Common Data Form (netCDF), binary raster, and plain text].

The complex influence of ENSO on droughts in Ecuador

In this study, we analyzed the influence of El Niño–Southern Oscillation (ENSO) on the spatio-temporal variability of droughts in Ecuador for a 48-year period (1965–2012). Droughts were quantified from 22 high-quality and homogenized time series of precipitation and air temperature by means of the Standardized Precipitation Evapotranspiration Index. In addition, the propagation of two different ENSO indices (El Niño 3.4 and El Niño 1xa0+xa02 indices) and other atmospheric circulation processes (e.g., vertical velocity) on different time-scales of drought severity were investigated. The results showed a very complex influence of ENSO on drought behavior across Ecuador, with two regional patterns in the evolution of droughts: (1) the Andean chain with no changes in drought severity, and (2) the Western plains with less severe and frequent droughts. We also detected that drought variability in the Andes mountains is explained by the El Niño 3.4 index [sea surface temperature (SST) anomalies in the central Pacific], whereas the Western plains are much more driven by El Niño 1xa0+xa02 index (SST anomalies in the eastern Pacific). Moreover, it was also observed that El Niño and La Niña phases enhance droughts in the Andes and Western plains regions, respectively. The results of this work could be crucial for predicting and monitoring drought variability and intensity in Ecuador.

The Ordesa and Monte Perdido National Park, Central Pyrenees

The Ordesa and Monte Perdido National Park was created in 1918 and enlarged in 1982 to highlight and protect spectacular high mountain relief dominated by limestone. Alpine tectonics resulted in the piling-up of south-verging thrust sheets leading to the thick sedimentary successions exposed in impressive vertical cliffs. The presence of massive limestones has favoured the development of deep canyons and karst landforms, including karren, dolines, and caves with large shafts. Quaternary glaciations contributed to increase the geomorphic diversity, forming cirques and stunning U-shaped valleys. Small glaciers from the Little Ice Age still remain on the north-facing slopes of the Monte Perdido. Periglacial processes in the most elevated areas of the National Park, as well as erosion in thick soils developed on marly limestone have produced unique geomorphological features.

SPEIbase: a global 0.5º gridded SPEI data base (I. NetCDF)

The dataset is freely available on the web repository of the Spanish National Research Council (CSIC) in three different formats (NetCDF, binary raster, and plain text).