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Summary: A new river flooding scheme for global climate applications: Off-line
evaluation over South America
B. Decharme,1
H. Douville,1
C. Prigent,2
F. Papa,3
and F. Aires4
Received 11 September 2007; revised 15 January 2008; accepted 14 March 2008; published 6 June 2008.
[1] Given their strong interaction with both climate and the carbon cycle, wetlands and
surface waters need to be parameterized in global general circulation models. For this
purpose, a new simple flooding river scheme is proposed and evaluated over South
America. The flood dynamics is described through the coupling between the ISBA land
surface model and the TRIP river routing model including a prognostic flood reservoir.
This reservoir fills when the river height exceeds a critical value and vice versa. The
reservoir interacts with the soil hydrology through infiltration and with the overlying
atmosphere through precipitation interception and free water surface evaporation. The
model is tested in off-line mode using the 10-year ISLSCP-2 atmospheric forcing. The
evaluation is made against satellite-derived inundation estimates as well as in situ river
discharge observations. Besides a basin-scale increase in annual surface evaporation, the
results show improved monthly discharges over the Amazon and Parana rivers, as well as
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