water Article Computationally Efficient Multivariate Calibration and Validation of a Grid-Based Hydrologic Model in Sparsely Gauged West African River Basins Thomas Poméon 1,*, Bernd Diekkrüger 1 and Rohini Kumar 2 1 Department of Geography, University of Bonn, Meckenheimer Allee 166, 53115 Bonn, Germany;
[email protected] 2 UFZ—Helmholtz Centre for Environmental Research, 04318 Leipzig, Germany;
[email protected] * Correspondence:
[email protected]; Tel.: +49-228-73-2401 Received: 6 September 2018; Accepted: 8 October 2018; Published: 10 October 2018 Abstract: The prediction of freshwater resources remains a challenging task in West Africa, where the decline of in situ measurements has a detrimental effect on the quality of estimates. In this study, we establish a series of modeling routines for the grid-based mesoscale Hydrologic Model (mHM) using Multiscale Parameter Regionalization (MPR). We provide a computationally efficient application of mHM-MPR across a diverse range of data-scarce basins using in situ observations, remote sensing, and reanalysis inputs. Model performance was first screened for four precipitation datasets and three evapotranspiration calculation methods. Subsequently, we developed a modeling framework in which the pre-screened model is first calibrated using discharge as the observed variable (mHM Q), and next calibrated using a combination of discharge and actual evapotranspiration data (mHM Q/ET). Both model setups were validated in a multi-variable evaluation framework using discharge, actual evapotranspiration, soil moisture and total water storage data. The model performed reasonably well, with mean discharge KGE values of 0.53 (mHM Q) and 0.49 (mHM Q/ET) for the calibration; and 0.23 (mHM Q) and 0.13 (mHM Q/ET) for the validation.