Dynamic parallelization of hydrological model simulations

1 This paper introduces the development of a dynamic parallel algorithm for conducting 2 hydrological model simulations. This new algorithm consists of a river network 3 decomposition method and an enhanced master-slave paradigm. The decomposition 4 method is used to divide a basin river network into a large number of subbasins, and the 5 enhanced master-slave paradigm is adopted to realize the function of this new dynamic 6 basin decomposition method through using the Message-Passing Interface (MPI) and 7 C++ language. This new algorithm aims to balance computation load and then to 8 achieve a higher speedup and efficiency of parallel computing in hydrological 9 simulation for the river basins which are delineated by high-resolution drainage 10 networks. This paper uses a modified binary tree codification method developed by Li 11 et al. (2010) to code drainage networks, and the basin width function to estimate the 12 possible maximum parallel speedup and the associated efficiency. As a case study, with 13 a hydrological model, the Digital Yellow River Model, this new dynamic parallel 14 algorithm is applied to the Chabagou basin in northern China. The application results 15 reveal that the new algorithm is efficient in the dynamic dispatching of simulation tasks 16 to computing processes, and that the parallel speedup and efficiency are comparable 17 with the estimations made by using the basin width function. Software availability 1 Program title: MPI control 2 Description: A graphic user interface for the MPI-based parallel hydrological model, 3 including the setup of parameters, the start/stop control of simulation, and 4 the performance and progress displays of the simulation 5 Developer: Description: The platform for parallel hydrological simulation, which dynamically 13 decomposes a basin river network into a number of subbasins and 14 dispatches them to slave computing processes 15 Developer: Dr.