A Community Hydrology - Land Surface Model

MESH is the hydrology land-surface (HLSS) configuration of Environment Canada's community environmental modelling system, MEC (Modélisation Environmentale Communautaire). The MEC system (as shown in Figure 1) allows different surface models to coexist within the same modelling framework so that they can easily be compared for the same experiment using exactly the same forcings, interpolation procedures, grid, time period, time step and output specifications. Furthermore, MEC is designed to facilitate coupling between models which focus on different components of the earth system with the objective of using the coupled models to produce operational weather and hydrological forecasts (Pietroniro et al. (2007)). An important feature of MESH is its ability to read atmospheric forcings from files ("off - line" mode) instead of obtaining them from an atmospheric model through the coupler. This makes it possible to test changes to the land surface schemes offline and to drive the HLSS with forcing data from other sources such as either from observations or from reanalysis products.

Figure 1. The MEC-MESH modelling system (CaPA - Canadian Precipitation Analysis; CaLDAS - Canadian Land Data Assimilation System)

Early stages in the evolution of Environment Canada's atmospheric-hydrologic-land-surface modelling system are described in Pietroniro et al. (2004). A conceptual framework for model development was initiated using different degrees of model coupling that range from a linked model which requires separate calibration of the atmospheric model and the hydrological model to a complete two way coupled model. MESH evolved from the WATCLASS model  which links WATFLOOD routing model to the Canadian Land Surface Scheme (CLASS), was used as a basis for coupling with both weather and climate atmospheric models. Please refer to the MESH wiki site for further details about the MESH modelling system and for a complete guide on how to setup, run and calibrate a MESH model.

MESH model users interested in compiling the MESH model source code or any other open source code may find this document useful.