Tosiyuki Nakaegawa and Masahiro Hosaka
Release Date: April 16, 2008

Effects of calibrated current speeds and groundwater scheme in a global river-flow model on river discharge and terrestrial water storage
Tosiyuki Nakaegawa1) and Masahiro Hosaka1)

1) Climate Research Department, Meteorological Research Institute

(Received: November 7, 2007)
(Accepted for publication: February 26, 2008)

Abstract:
This study modifies a Global River-flow model (GRiveT) to more realistically represent groundwater and river-flow processes and examines the effects of these modifications on the reproducibility of the hydrological processes. These modifications include assigning calibrated spatially distributed current speeds and implementing a groundwater scheme. A current speed calibration method is proposed to eliminate river discharge phase differences (RPDs) between the observation and the simulation. We performed nine-year integrations of the modified version of GRiveT. The experimental results were then compared with the observed data for 70 of the world’s major rivers. The proposed calibration method provides reasonable calibrated speeds that eliminate RPD for most of the 70 rivers considered. The calibration significantly improves the river discharge correlation coefficient and phase difference and improves the terrestrial water storage (TWS) correlation coefficient and phase difference to a lesser extent. However, there was little improvement to river discharge and TWS amplitudes. The implementation of the groundwater scheme improves river discharge and TWS correlation coefficients and phase differences for experiments without calibration. The calibration can compensate for the disadvantages of not implementing the groundwater scheme.

[Full Text]

To cite this article:
Tosiyuki Nakaegawa and Masahiro Hosaka: “Effects of calibrated current speeds and groundwater scheme in a global river-flow model on river discharge and terrestrial water storage”, Hydrological Research Letters, Vol. 2, pp.18-21, (2008) .

doi:10.3178/hrl.2.18
JOI JST.JSTAGE/hrl/2.18
Copyright (c) 2008 Japan Society of Hydrology and Water Resources