A variable velocity method for global river routing model

Papers published in Hydrology and Earth System Sciences Discussions are under open-access review for the journal Hydrology and Earth System Sciences Abstract This paper presents an attempt of simulating daily fluctuations of river discharge at global scale. Total Runoff Integrating Pathways (TRIP) is a global river routing model which can help to isolate the river basins, inter-basin transport of water through river channels, as well as collect and route runoff to the river mouths for all the major rivers. 5 In the previous version of TRIP (TRIP 1.0), a simple approach of constant river flow velocity is used. In general, that approach is sufficient to model mean long-term discharges. However, to model short-term fluctuations, more sophisticated approach is required. In this study, we implement a variable streamflow velocity method to TRIP (TRIP 2.0) and validate the new approach over the world's 20 major rivers. Two nu-10 merical experiments, one with the TRIP 1.0 and another with TRIP 2.0 are performed. Input runoff is taken from the multi-model product provided by the second Global Soil Wetness Project. For the rivers which have clear daily fluctuations of river discharge, TRIP 2.0 shows advantages over TRIP 1.0, suggesting that TRIP 2.0 can be used to model flood events.