An unstructured-mesh atmospheric model for nonhydrostatic dynamics

An unstructured-mesh atmospheric model for nonhydrostatic dynamics: Towards optimal mesh resolution

“…Examples include weather in long winding valleys and mountainous areas, onset and evolution of radiation fog or stratiform clouds, precipitation or extreme events forecasting. This paper advances the three-dimensional, nonhydrostatic, limited-area model designed for flexible fully unstructured meshes [45] by introducing its implementation on tetrahedral based median-dual meshes that enable a wide range of mesh refinement strategies.…”

“…The applicability of NFT methods to gas dynamics was demonstrated through verifications against benchmarks for all-speed aerodynamic flows with favourable comparisons to established solutions (theoretical and numerical) and convergence studies. Subsequent developments of the unstructured meshes based NFT integrators focused on meteorological applications producing models for simulating idealised hydrostatic dynamics of the planetary atmosphere [52], reduced 2D soundproof models for simulation of nonhydrostatic gravity-wave dynamics [53,44] and their consequent generalisation to 3D mesoscale modelling of nonhydrostatic dynamics [45] -all supported with extensive verification studies.…”

“…The underlying concept of the numerical model used in the current study is presented in detail in [45]. In the model, all dependent variables are colocated, benefiting memory and communication requirements compared to staggered arrangements.…”

“…The implicit large eddy simulation (ILES) properties of MPDATA-based high-Reynolds-number solvers were widely documented in the context of structured grids [24,25,7,26,55]. More recently, they were also demonstrated for unstructured meshes [53,44,45] and verified against published data and LES/ILES results generated with established codes in [45]. For unstructured meshes with large variation in spatial resolution, the ILES capability is especially practical, as it circumvents evaluation of explicit subgrid-scale models and construction of commutative filters for LES [27], in particular, and does not impede the stability of calculations.…”

“…The preceding works on the nonhydrostatic unstructured-mesh NFT models [53,44,45] verified the excellent accuracy of the finite-volume approach, using benchmarks from both analytic and laboratory results, and comparing unstructured-mesh results to the corresponding results obtained with the structured-grid EULAG model [32]. The previously studied physical problems representative of mesoscale dynamics included nonhydrostatic mountain waves at weak and strong background stratification (with linear and nonlinear flow responses, respectively), amplification and breaking of deep stratospheric gravity waves, low Froude number flows past steep isolated 3D mountain, and evolution of convective planetary boundary layer.…”