Going local: evaluating and regionalizing a global hydrological model’s simulation of river flows in a medium-sized East African basin

Siderius, Christian, Biemans, Hester, Kashaigilic, Japhet J. and Conway, Declan ORCID: 0000-0002-4590-6733 (2018) Going local: evaluating and regionalizing a global hydrological model’s simulation of river flows in a medium-sized East African basin. Journal of Hydrology: Regional Studies, 19. ISSN 2214-5818

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Abstract

Study region: The Rufiji basin, East Africa. Study focus: Rapid advances in global hydrological model (GHM) resolution, model features, and in situ and remotely sensed datasets are driving progress towards local relevance and application. Despite their increasing use, however, evaluation of local hydrological performance of GHMs is rare. In this paper, we examine the performance of a well-known GHM (LPJmL, recently modified to ∼9 km resolution) with and without modest steps to regionalise the model. We consider the Rufiji river basin, an economically important medium-size basin in eastern Africa. New hydrological insights for the region: Our results indicate that the unmodified GHM does provide a reasonable first approximation of spatial variability in mean flow conditions, but scores rather poorly on seasonal and inter-annual variability. For the model to achieve levels of performance indicators comparable with bespoke modelling, modifications to model inputs, additional runoff delay and wetland parameterization were required. The largest improvements are associated with adjustments in precipitation and enhanced runoff delay. With the modified version, as a proof of concept, we show that a well-known drying trend in a major tributary of the Rufiji can be explained by implementing irrigation abstractions in the model. Overall, the results suggest that with limited and fairly simple modification GHMs can be regionalised to allow their use for scenario testing and further exploration of key local processes in basins with limited observational data.

Item Type:	Article
Official URL:	https://www.sciencedirect.com/journal/journal-of-h...
Additional Information:	© 2018 The Authors
Divisions:	Grantham Research Institute
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences
Date Deposited:	04 Dec 2018 17:25
Last Modified:	11 Dec 2024 21:46
Projects:	NE/M020398/1
Funders:	Natural Environment Research Council, Department for International Development, Dutch Ministry of Agriculture, Nature and Food Quality
URI:	http://eprints.lse.ac.uk/id/eprint/90979

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