73 shared publications
Estación Experimental de Aula Dei; Consejo Superior de Investigaciones Científicas (EEAD-CSIC); Zaragoza Spain
57 shared publications
Laboratory of Hydrology and Water Management—Ghent University; Coupure links 653, 9000 Gent, Belgium
32 shared publications
Northern Rivers Institute; University of Aberdeen; Aberdeen AB24 3UF UK
24 shared publications
Instituto Pirenaico de Ecología, Spanish National Research Council (IPE-CSIC), Campus de Aula Dei, P.O. Box 13034, E-50059 Zaragoza, Spain
24 shared publications
University of California
(2011 - 2018)
Here we propose a new methodology for calculating the Standardized Evapotranspiration Deficit Index (SEDI) at the global scale using the difference between the actual evapotranspiration (ET) and the atmospheric evaporative demand (AED). ET was estimated by the Global Land Evaporation Amsterdam Model (GLEAM) v3a. The SEDI has been proposed recently to quantify drought severity based on the difference between actual evapotranspiration (ET) and the atmospheric evaporative demand (AED). Our findings demonstrate that, regardless of the AED dataset used for calculations, a log-logistic distribution is needed in order to fit the ED time series. As such, in many regions worldwide, the SEDI is insensitive to the AED method used for calculation. The SEDI showed significant correlations with the Standardized Precipitation Evapotranspiration Index (SPEI) across a wide range of regions, particularly for short SPEI time-scales. Overall, while this work provides a robust approach for calculating spatially and temporally comparable SEDI estimates, regardless of the climate region and land surface conditions, further studies remain needed to assess the performance and the applicability of the SEDI to quantify drought severity across varying crop and natural vegetation areas.
We have analysed the response of hydrological droughts to climatic droughts in different natural basins of United States of America. For this purpose we selected 289 complete series from an initial data set of 702 gauging stations, covering the period between 1940 and 2013. Drainage basins were obtained for each gauging station using a digital terrain model, and climate series (precipitation and the atmospheric evaporative demand) were obtained for each drainage series. A number of topographic, edaphic and remote sensing variables were quantified for each basin. A hydrological drought index (The Standardized Stream Flow Index-SSI) was obtained for each basin and the Standardized Precipitation Evapotranspiration Index (SPEI) was used as a metric of climatic drought severity. Relationship between different SPEI time scales and the SSI was quantified using Pearson’s correlations and the general patterns of response of hydrological droughts to climatic droughts were identified using a principal component analysis. In general there is a response of SSI to short SPEI time-scales but strong seasonality in this response is also found. Coherent geographic patterns were obtained from the analysis and the factors that control the different responses were analysed by means of a predictive discriminant analysis. Independent analysis for three periods (1940-1964, 1965-1989 and 1989-2013) were also performed and showed not important changes in the response of the SSI to the SPEI in the past 65 years.