In this work, the impact of topography on the geostrophic adjustment processis discussed with a simple two-layer shallow water model, in which the lower-layer fluid isinitially stationary while the upper-layer is pert...In this work, the impact of topography on the geostrophic adjustment processis discussed with a simple two-layer shallow water model, in which the lower-layer fluid isinitially stationary while the upper-layer is perturbed by the impulsive injection of momentum.During the geostrophic adjustment process of this ideal model, the initial kinetic energy isreleased and a fraction of it is converted into potential energy of the final geostrophicallyadjusted state. Thus, after the geostrophic adjustment, the kinetic energy of the system is reducedwhile the potential energy is enhanced. As the topographic effect is considered, it is found thatthe decrease of the kinetic energy (ΔKE) and the increase of the potential energy (ΔPE) of thesystem are weakened as compared to the case that the lower boundary is flat. Furthermore, thetopographic effect on APE is less pronounced than that on ΔKE, which implicates that the topographytends to inhibit the energy dispersion of the inertio-gravity wave. The numerical simulation of thegeostrophic adjustment process shows that, due to the impact of topography, the convergence anddivergence in the low layer are reduced and the undulation of the interface between the lower-layerand upper-layer is weakened. This means that the amplitude of the inertio-gravity wave is decreased,and thus, the energy radiated by the inertio-gravity wave is lessened.展开更多
基金This work is supported by the National Natural Science Foundation of China under Grant Nos. 40175005, 40333025 and bythe Natural Science Foundation of Jiangsu Province under Grant No. BK2001042.
文摘In this work, the impact of topography on the geostrophic adjustment processis discussed with a simple two-layer shallow water model, in which the lower-layer fluid isinitially stationary while the upper-layer is perturbed by the impulsive injection of momentum.During the geostrophic adjustment process of this ideal model, the initial kinetic energy isreleased and a fraction of it is converted into potential energy of the final geostrophicallyadjusted state. Thus, after the geostrophic adjustment, the kinetic energy of the system is reducedwhile the potential energy is enhanced. As the topographic effect is considered, it is found thatthe decrease of the kinetic energy (ΔKE) and the increase of the potential energy (ΔPE) of thesystem are weakened as compared to the case that the lower boundary is flat. Furthermore, thetopographic effect on APE is less pronounced than that on ΔKE, which implicates that the topographytends to inhibit the energy dispersion of the inertio-gravity wave. The numerical simulation of thegeostrophic adjustment process shows that, due to the impact of topography, the convergence anddivergence in the low layer are reduced and the undulation of the interface between the lower-layerand upper-layer is weakened. This means that the amplitude of the inertio-gravity wave is decreased,and thus, the energy radiated by the inertio-gravity wave is lessened.
