HYPROM hydrology surface‐runoff prognostic model

The major objective of this study was to develop a hydrology model (HYPROM) to simulate overland watershed processes based on advanced numerical and parameterization methods. The resulting model, HYPROM, was designed for real‐time watershed prediction. The model solves grid point‐based shallow water equations with numerical approaches that include an efficient explicit time‐differencing scheme for the gravity wave components and a physically based and numerically stable implicit scheme for the friction slope terms. The model dynamics (advection, diffusion, and height gradient force) are explicitly represented, whereas the model physics (e.g., friction slope) are parameterized, i.e., subgrid effects are expressed in terms of the model grid point variables. The fact that the modeling governing equations for momentum and mass are all prognostic makes HYPROM distinct to most other prognostic hydrology systems. The model uses real topography, river routing, and land cover data to represent surface influences. The HYPROM calculations can be executed offline (i.e., independent of a driving atmospheric model) or online as a callable routine of a driving atmospheric model. The model is applicable across a broad range of spatial scales ranging from local to regional and global scales. The model can be set up over different geographic domains and can run efficiently on conventional computer platforms. Finally, the model can be used either for hydrologic forecasts or climate studies if embedded as a component of an atmospheric climate model.