模式网格均匀性对涡旋系统数值模拟的影响研究

Impact of the Grid Uniformity on Numerical Simulation of Vortices

关键词:  网格均匀性  分辨率  涡旋系统  数值模拟

Key words:  grid uniformity  resolution  vortex system  numerical simulation

摘要:

基于阴阳网格全球-区域通用大气数值模式（YUNMA），评估了不同网格配置和分辨率对涡旋系统模拟结果的影响。通过网格坐标系旋转，获得涡旋运动路径上具有不同均匀性的网格，并结合理想试验与实际台风个例模拟，分析了不同网格均匀性和分辨率对涡旋或台风路径、强度、结构及降水模拟表现的影响。结果表明：（1）网格均匀性对理想涡旋系统的纯动力数值模拟结果影响明显，非均匀网格造成涡旋路径偏移，并加速涡旋强度和移动速度衰减。（2）低分辨率模式较高分辨率模式对网格均匀性更加敏感。相同网格变率情况下，高分辨率动力模式模拟的涡旋强度和涡旋路径更加稳定，涡旋运动速度也能够得到更好地维持。（3）实际台风模拟也受到网格均匀性的显著影响，均匀网格协同高分辨率模式能够更准确地捕捉台风路径，台风强度得以更好保持，而低分辨率且非均匀网格配置导致台风中心位置偏移，模拟路径偏差增大。同时，均匀网格模式能更准确模拟台风降水，提高降水TS评分。网格均匀性不仅制约模式次网格物理过程参数化效果，还影响模式动力计算精度的空间分布一致性，从而影响包含天气系统移动、强度和降水在内的数值模拟效果。

Abstract:

Using the Yin-Yang-grid Unified Model for the Atmosphere (YUNMA), we evaluated the impact of varying grid uniformity and horizontal resolutions on the simulation of vortices. Grids with different uniformity were obtained along the vortex paths through coordinated rotation. Combined with idealized vortex experiments and real typhoon case simulations, we analyzed the effects of grid uniformity and horizontal resolution on the simulated performances of the path, intensity, structure and precipitation of the vortex or typhoon. The key findings are as follows. (1) The grid uniformity clearly influences the purely dynamical numerical simulation results of the idealized vortex. Non-uniform grid tended to disturb the path of vortex and accelerate the decay of vortex intensity and moving speed. (2) Low-resolution simulation is more sensitive to the grid uniformity than the high-resolution simulation. The high-resolution dynamical model simulated more stable vortex intensity and paths than low-resolution models with the same grid- spacing variability, and the moving speed of the vortex was more easily maintained in numerical simulations. (3) Real typhoon simulations are also significantly affected by the grid uniformity. Uniform grid combined with high-resolution models can more accurately capture the path and intensity of typhoon. The low-resolution and non-uniform grid configurations model, however, simulated offset path of the typhoon, leading to significantly increased path simulation errors. Meanwhile, uniform-grid model demonstrated superior capability in reproducing precipitation with high Threat Score (TS). The non-uniform grids not only restrict the effectiveness of subgrid-scale physics parameterizations but also influence the spatial consistency of dynamical computational accuracy in numerical models, thereby affecting the overall simulation performance, including the movement, intensity, and precipitation of weather systems.