Evaluation on the tracer simulation under different advection schemes in the ocean model

Advection scheme is one of the core challenges in the computational fluid dynamics, which restricts the capacity of model performance in many research areas including the oceanographic modelling studies. Here in this study, we compared the newly developed algorithm HSIMT (advection scheme with High-order Spatial Interpolation at the Middle Temporal level) with the well-known scheme MPDATA (Multidimensional Positive-Definite Advective Transport Algorithm), in the 1-dimensional idealized simulation and the 3-dimensional realistic river plume simulations. The river plume simulation was done with a mainstream ocean model ROMS (Regional Ocean Modeling System). The results showed that in the 1-dimensional test both HSIMT and MPDATA can converge to the analytical results, but HSIMT converges much faster and does not produce overshooting around the sharp front. Accuracy of HSIMT is also free from the choice of timestep, unlike MPDATA. In the ROMS simulation of a surface-trapped river plume, HSIMT also showed great advantages. Results simulated by MPDATA is highly relied on the model resolution, but when the resolution is high enough the results approached to that simulated by HSIMT. The results of this study could assist the further understanding on capacity of advection schemes and further promote the developments of ocean models.