A global streamflow reanalysis for 1980–2018

Alfieri, Lorenzo; Lorini, Valerio; Hirpa, Feyera A.; Harrigan, Shaun; Zsoter, Ervin; Prudhomme, Christel; Salamon, Peter. 2020 A global streamflow reanalysis for 1980–2018. Journal of Hydrology X, 6, 100049. 12, pp. 10.1016/j.hydroa.2019.100049

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Official URL: http://dx.doi.org/10.1016/j.hydroa.2019.100049

Abstract/Summary

Global and continental scale hydrological reanalysis datasets receive growing attention due to their increasing number of applications, ranging from water resources management, climate change studies, water related hazards and policy support. Until recently, their use was mostly limited to qualitative assessments, due to their coarse spatial and temporal resolution, large uncertainty and bias in the model output, and limited extent of the dataset in space and time. This research reports on the setup of a gridded hydrological model with quasi-global coverage, able to reproduce a seamless 39-year streamflow simulation in all world’s medium to large river basins. The model was calibrated at 1226 river sections with a total drainage area of 51 million km2 within 66 countries, using ECMWF’s latest atmospheric reanalysis ERA5. A performance assessment revealed large improvements in reproducing past discharge observations, in comparison to the calibration used in the current operational setup of the hydrological model as part of the Copernicus – Global Flood Awareness System (GloFAS, www.globalfloods.eu), with median scores of Kling-Gupta Efficiency KGE = 0.67 and correlation r = 0.8. The simulation bias was also dramatically reduced and narrowed around zero, with more than 60% of stations showing percent bias within ±20%. Pronounced regional differences in the simulation results remain, pointing out the need for detailed investigation of the hydrological processes in specific regions, including parts of Africa and South Asia. In addition, observed discharges with high data quality is key to achieving skillful model output. The new calibrated model will become part of the operational runs of GloFAS in the next system release foreseen for Spring 2020, together with a near real time extension of the streamflow reanalysis.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.hydroa.2019.100049
UKCEH and CEH Sections/Science Areas:	UKCEH Fellows
ISSN:	2589-9155
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	hydrological reanalysis, global hydrology, model calibration, Global Flood Awareness System (GloFAS), distributed modelling
NORA Subject Terms:	Hydrology
Date made live:	06 Jan 2020 12:04 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/526355

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.hydroa.2019.100049

UKCEH and CEH Sections/Science Areas:

UKCEH Fellows

ISSN:

2589-9155

Additional Information. Not used in RCUK Gateway to Research.:

Open Access paper - full text available via Official URL link.

Additional Keywords:

hydrological reanalysis, global hydrology, model calibration, Global Flood Awareness System (GloFAS), distributed modelling