摘要
随着计算机和计算理论的发展,数值模式正在向全球化、精细化发展,以适应多尺度、多目的应用的要求,从而模糊了大气环流模式和中尺度数值模式的界限,其主要手段就是改进模式动力框架、离散化手段、计算方法、物理过程的普适性。在实际应用中如何提高模式的多尺度计算性能则是问题关键。该文从模式球面坐标系、网格构造、离散化方法的动力特性、垂直坐标和地形处理以及对物理过程的要求出发,探讨分析多尺度大气数值模式的特点:全球/区域可选、非静力近似、具有良好的频散关系和详细的物理过程,垂直高度坐标和"剪切"地形对多尺度通用模式的改良十分重要。除上述特点外,模式所采用的计算方法也应该最大限度地描述大气动力过程特性,采用高性能计算方案有利于多尺度预报。结合当前多尺度预报的国际研究热点和开发前沿,探讨我国新一代多尺度数值预报系统GRAPES的进一步发展及改进方向。
With the advances of computer and computational technique,multi-scale multi-task numerical model is being developed for fine prediction in a global scope.The difference between a general circulation model and a mesoscale model becomes unclear except for the forcing arrangement,and a global model tends to be used for severe storm prediction and study of mesoscale convective systems.Development of a multi-scale model can be stated in improving the universality of model dynamics,discretion scheme,computational algorithm and physics,and the key issue is improving the multi-scale properties of each parts.It calls for no approximation to the dynamics of the real atmosphere and detailed arrangement of the topography.Numerical schemes and the computational algorithm should be flexible,accurate and stable,so that can be used to various grid-spacing systems.Considering the spherical mesh,grid structure and dynamical feature of discretion,the quasi-uniform mesh with fine numerical dispersion feature is preferred in the recent development of numerical models.Reduced grid,cubed grid,icosahydron grid,Yin-Yang grid and Voronoi grid are discussed. In addition to detailed model physics,non-hydrostatic model with global and regional configuration and unified frame is the fashion of multi-scale model.The vertical coordinate and terrain arrangement are important for proper description of dynamical and thermo-dynamical processes.Vertical z coordinate and＂shaved-cell＂topography have boosted the unified model,especially in high-resolution case.Besides,numerical method should describe the intrinsic nature of dynamical processes,and provides sub-grid information during the temporal integration.Conservation of the main model properties is known as the key factor for long-term integration.High performance numerical scheme favors the multi-scale application of a model and is of great attraction.The pioneer researches over the world are summarized,which provides reference for the development of the multi-scale model system,GRAPES,in China.
出处
《应用气象学报》
CSCD
北大核心
2010年第2期129-138,共10页
Journal of Applied Meteorological Science
基金
国家自然科学基金项目(40875065)
国家青年科学基金项目(40805045)
中国气象科学研究院基本科研业务费(2008R001)
灾害天气国家重点实验室基本科研业务费(2008LASWZI05)共同资助
关键词
多尺度预报
非静力近似
通用模式
计算技术
multi-scale prediction
non-hydrostatic formulation
unified model
computational techniques
