Twentieth‐century hydrometeorological reconstructions to study the multidecadal variations of the water cycle over France
Date
2017
Authors
Bonnet, Rémy.
Boé, Julien
Dayon, Gildas
Martin, Éric
Journal Title
Journal ISSN
Volume Title
Publisher
Water Resources Research
Abstract
Characterizing and understanding the multidecadal variations of the continental hydrological cycle is a challenging issue given the limitation of observed data sets. In this paper, a new approach to derive twentieth century hydrological reconstructions over France with an hydrological model is presented. The method combines the results of long‐term atmospheric reanalyses downscaled with a stochastic statistical method and homogenized station observations to derive the meteorological forcing needed for hydrological modeling. Different methodological choices are tested and evaluated. We show that using homogenized observations to constrain the results of statistical downscaling help to improve the reproduction of precipitation, temperature, and river flows variability. In particular, it corrects some unrealistic long‐term trends associated with the atmospheric reanalyses. Observationally constrained reconstructions therefore constitute a valuable data set to study the multidecadal hydrological variations over France. Thanks to these reconstructions, we confirm that the multidecadal variations previously noted in French river flows have mainly a climatic origin. Moreover, we show that multidecadal variations exist in other hydrological variables (evapotranspiration, snow cover, and soil moisture). Depending on the region, the persistence from spring to summer of soil moisture or snow anomalies generated during spring by temperature and precipitation variations may explain river flows variations in summer, when no concomitant climate variations exist.
Description
Keywords
UN SDG 13: Climate Action, #journal article, Pacific Climate Impacts Consortium (PCIC)
Citation
Bonnet, Rémy., Boé, J., Dayon, G., & Martin, E. (2017). Twentieth‐century hydrometeorological reconstructions to study the multidecadal variations of the water cycle over France. Water Resources Research, 53(10), 8366–8382. https://doi.org/10.1002/2017WR020596