Parallel Domain-decomposed Taiwan Multi-scale Community Ocean Model (PD-TIMCOM)

The Parallel Domain-decomposed Taiwan Multi-scale Community Ocean Model (PD-TIMCOM) was developed to provide a flexible and efficient community ocean model for simulating a variety of idealized and real ocean flows over a wide range of scales and boundary conditions. The model is particularly targeted at resolving multi-scale dynamics in the ocean environment, ranging from small scale turbulence to the global circulation gyres. The novel parallel algorithm improves the efficiency of the Error Vector Propagating (EVP) method, a simple direct solver for the typical pressure Poisson equations in the PD-TIMCOM. The new approach is ideal for multiple processes and takes advantage of parallel domain-decomposition, which can significantly reduce the operational counts and computational costs simultaneously. The speed-up is proportional to the number of domains, thus making the PD-TIMCOM a practical eddy-resolving global ocean model for climate projection. We illustrate the parallel performance based on the 1/4° global adaptation of PD-TIMCOM. Our results show accurate meso-scale variability, the reasonable separation of several western boundary currents from the coast, and the appropriate watermass distribution in the global ocean. Consistent with satellite altimetry, the results also show clear mean fronts in the Kuroshio Extension and extensive Kuroshio–Oyashio interaction. This leads to a quasi-equilibrium eddy field associated with three meandering jets in the Kuroshio Extension and Gulf Stream.