Projected hydrologic changes over the north of the Iberian Peninsula using a Euro-CORDEX multi-model ensemble

Patricio Yeste; Juan José Rosa-Cánovas; Emilio Romero-Jiménez; Matilde García-Valdecasas Ojeda; Sonia R Gámiz-Fortis; Yolanda Castro-Díez; María Jesús Esteban-Parra

doi:10.1016/j.scitotenv.2021.146126

Projected hydrologic changes over the north of the Iberian Peninsula using a Euro-CORDEX multi-model ensemble

Sci Total Environ. 2021 Jul 10:777:146126. doi: 10.1016/j.scitotenv.2021.146126. Epub 2021 Mar 1.

Authors

Patricio Yeste¹, Juan José Rosa-Cánovas², Emilio Romero-Jiménez³, Matilde García-Valdecasas Ojeda⁴, Sonia R Gámiz-Fortis², Yolanda Castro-Díez², María Jesús Esteban-Parra²

Affiliations

¹ Dept. Applied Physics, University of Granada, Spain; Andalusian Institute for Earth System Research (IISTA-CEAMA), University of Granada, Spain. Electronic address: pyeste@ugr.es.
² Dept. Applied Physics, University of Granada, Spain; Andalusian Institute for Earth System Research (IISTA-CEAMA), University of Granada, Spain.
³ Dept. Applied Physics, University of Granada, Spain.
⁴ Instituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Italy.

PMID: 33684765
DOI: 10.1016/j.scitotenv.2021.146126

Abstract

This study explores the impacts of climate change on the hydrology of the headwater areas of the Duero River Basin, the largest basin of the Iberian Peninsula. To this end, an ensemble of 18 Euro-CORDEX model experiments was gathered for two periods, 1975-2005 and 2021-2100, under two Representative Concentration Pathways (RCP4.5 and RCP8.5), and were used as the meteorological forcings of the Variable Infiltration Capacity (VIC) during the hydrological modelling exercise. The projected hydrologic changes for the future period were analyzed at annual and seasonal scales using several evaluation metrics, such as the delta changes of the atmospheric and land variables, the runoff and evapotranspiration ratios of the overall water balance, the snowmelt contribution to the total streamflow and the centroid position for the daily hydrograph of the average hydrologic year. Annual streamflow reductions of up to 40% were attained in various parts of the basin for the period 2071-2100 under the RCP8.5 scenario, and resulted from the precipitation decreases in the southern subwatersheds and the combined effect of the precipitation decreases and evapotranspiration increases in the north. The runoff and the evapotranspiration ratios evinced a tendency towards an evaporative regime in the north part of the basin and a strengthening of the evaporative response in the south. Seasonal streamflow changes were mostly negative and dependent on the season considered, with greater detriments in spring and summer, and less intense ones in autumn and winter. The snowmelt contribution to the total streamflow was strongly diminished with decreases reaching -80% in autumn and spring, thus pointing to a change in the snow regime for the Duero mountains. Finally, the annual and seasonal changes of the centroid position accounted for the shape changes of the hydrograph, constituting a measure of seasonality and reflecting high correlations degrees with the streamflow delta changes.

Keywords: Duero River Basin; Euro-CORDEX; Evaluation metrics; Projections; VIC model; Water balance.