The river routing model TRIP (Total Runoff Integrating Pathways) is a model developed by the University of Tokyo for applications to a global scale.

It is a simplified model where the water system is defined on a grid of 1 ° by 1 ° or ½ ° by ½ ° resolution.

The river flows are calculated in each grid point according to a flow velocity constant of 0.5m / s across the globe [Oki and Sud, 1998].


Schematic representation of the ISBA-TRIP hydrologic modelling system used in the late 2000s for climate and hydrological applications at the global scale (following Decharme and Douville 2007).

ISBA-TRIP is the old continental surface modeling system (Decharme and Douville 2007, Alkama et al., 2010) used in the late 2000s in the CNRM-CM5 coupled model who participated to CMIP5 and in global hydrological applications.

TRIP was coupled every days with the 3-layers ISBA "force-restore" land surface scheme (Boone et al. 1999) to simulate river discharges for climate and hydrological applications at the global scale. Infiltration in ISBA was calculated as the difference between surface runoff and throughfall rate (precipitation not intercepted by the canopy + dripping from interception reservoir+ snowmelt). The snowpack is computed via a simple one-layer snow scheme (Douville et al., 1995). Surface runoff was calculated via a set of subgrid parameterization to account for heterogeneities of precipitation, soil infiltration capacity, topography, and vegetation within each grid cell (Decharme and Douville 2006).

Today, ISBA-TRIP has been replaced by ISBA-CTRIP with a more ambitious representation of continental surfaces.

  Publications :



  • Alkama, R., Decharme, B., Douville, H., Becker, M., Cazenave, A., Sheffield, J., et al. (2010). Global evaluation of the ISBA-TRIP continental hydrological system. Part I: Comparison to GRACE terrestrial water storage estimates and in situ river discharges. Journal of Hydrometeorology, 11(3).
  • Decharme B., 2007 : Influence of the runoff representation on continental hydrology using the NOAH and the ISBA land surface models. J. Geophys. Res., 112, D19108,
  • Douville, H., Royer, J.-F., & Mahfouf, J.-F. (1995). A new snow parameterization for the Météo-France climate model: Part I: validation in stand-alone experiments. Climate Dynamics.