Assessing Adaptive Mesh Refinement (AMR) in a Forced Shallow-Water Model with Moisture

Ferguson, J. O.; Jablonowski, Christiane; Johansen, Hans

doi:10.1175/mwr-d-18-0392.1

Cited by 5 publications

(5 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The second test case is similar to the barotropic unstable jet test case (Galewsky et al, 2004). This test case was analyzed in Ferguson et al (2019), however, in their work, the rain formed is considered as precipitated and is removed from the model. In our analysis, we consider the rain to be advected as a tracer following Zerroukat and Allen (2015).…”

Section: Moist Shallow-water Modelmentioning

confidence: 99%

Topography based local spherical Voronoi grid refinement on classical and moist shallow-water finite volume models

Santos¹,

Peixoto²

2021

Preprint

View full text Add to dashboard Cite

Abstract. Locally refined grids for global atmospheric models are attractive since they are expected to provide an alternative to solve local phenomena without the requirement of a global high-resolution uniform grid, whose computational cost may be prohibitive. The Spherical Centroidal Voronoi Tesselations (SCVT), as used in the atmospheric Model for Prediction Across Scales (MPAS), allows a flexible way to build and work with local refinement. Alongside, the Andes Range plays a key role in the South American weather, but it is hard to capture its fine structure dynamics in global models. This paper describes how to generate SCVT grids that are locally refined in South America and that also capture the sharp topography of the Andes Range by defining a density function based on topography and smoothing techniques. We investigate the use of the mimetic finite volume scheme employed in the MPAS dynamical core on this grid considering the non-linear classic and moist shallow-water equations on the sphere. We show that the local refinement, even with very smooth transitions from different resolutions, generates spurious numerical inertia-gravity waves that may even numerically de-stabilize the model. In the moist shallow-water model, where physical processes such as precipitation and cloud formation are included, our results show that the local refinement may generate spurious rain that is not observed in uniform resolution SCVT grids. Fortunately, the spurious waves originate from small-scale grid-related numerical errors and therefore can be mitigated using small amounts of numerical diffusion. We show that, in some cases, the clouds are better represented in a variable resolution grid when compared to a respective uniform resolution grid with the same number of cells, while in other cases, grid effects can deteriorate the cloud and rain representation.

show abstract

Section: Moist Shallow-water Modelmentioning

confidence: 99%

Topography based local spherical Voronoi grid refinement on classical and moist shallow-water finite volume models

Santos¹,

Peixoto²

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The second test case is similar to the barotropic unstable jet test case (Galewsky et al, 2004). This test case was analyzed in Ferguson et al (2019); however, in their work, the rain formed is considered precipitated and is removed from the model. In our analysis, we consider the rain to be advected as a tracer following Zerroukat and Allen (2015).…”

Section: Moist Shallow-water Modelmentioning

confidence: 99%

Topography-based local spherical Voronoi grid refinement on classical and moist shallow-water finite-volume models

Santos

Peixoto

2021

Geosci. Model Dev.

View full text Add to dashboard Cite

Abstract. Locally refined grids for global atmospheric models are attractive since they are expected to provide an alternative to solve local phenomena without the requirement of a global high-resolution uniform grid, whose computational cost may be prohibitive. Spherical centroidal Voronoi tessellation (SCVT), as used in the atmospheric Model for Prediction Across Scales (MPAS), allows a flexible way to build and work with local refinement. In addition, the Andes Range plays a key role in the South American weather, but it is hard to capture its fine-structure dynamics in global models. This paper describes how to generate SCVT grids that are locally refined in South America and that also capture the sharp topography of the Andes Range by defining a density function based on topography and smoothing techniques. We investigate the use of the mimetic finite-volume scheme employed in the MPAS dynamical core on this grid considering the nonlinear classic and moist shallow-water equations on the sphere. We show that the local refinement, even with very smooth transitions from different resolutions, generates spurious numerical inertia–gravity waves that may even numerically destabilize the model. In the moist shallow-water model, wherein physical processes such as precipitation and cloud formation are included, our results show that the local refinement may generate spurious rain that is not observed in uniform-resolution SCVT grids. Fortunately, the spurious waves originate from small-scale grid-related numerical errors and can therefore be mitigated using fourth-order hyperdiffusion. We exploit a grid geometry-based hyperdiffusion that is able to stabilize spurious waves and has very little impact on the total energy conservation. We show that, in some cases, the clouds are better represented in a variable-resolution grid when compared to a respective uniform-resolution grid with the same number of cells, while in other cases, grid effects can affect the cloud and rain representation.

show abstract

“…Participants included developers for the MOM6 (Adcroft et al., 2019), CROCO (Hilt et al., 2020) and NEMO (Madec et al., 2019) ocean models, the Community Atmosphere Model (CAM, Neale et al., 2010) which is part of the Community Earth System Model (CESM, Danabasoglu et al., 2020) from the National Center for Atmospheric Research (NCAR), the Energy Exascale Earth System Model (E3SM) (Golaz et al., 2019), the DYNAMICO (Dynamical Core on Icosahedral Grid, Dubos et al., 2015), the Unified Model (Walters et al., 2017), LFRic (S. Adams et al., 2019; Melvin et al., 2019) and ICON‐IAP (Icosahedral Nonhydrostatic model at the Institute for Atmospheric Physics, Gassmann, 2013) atmosphere models, and the CLUBB (Cloud Layers Unified By Binormals) parameterization of turbulence and clouds in the atmosphere (Larson, 2017). Participants also included developers of Adaptive Mesh Refinement (AMR) methods for geophysical flows via the CHOMBO library (M. Adams et al., 2019; Ferguson et al., 2016, 2019) as well as WAVETRISK (Dubos & Kevlahan, 2013; Kevlahan & Dubos, 2019). Since the group was deliberately heterogeneous, the workshop began with a series of overview talks on each component (atmosphere, ocean, physics, couplers).…”

Section: Introductionmentioning

confidence: 99%

Reconciling and Improving Formulations for Thermodynamics and Conservation Principles in Earth System Models (ESMs)

Lauritzen

Kevlahan

Toniazzo

et al. 2022

J Adv Model Earth Syst

View full text Add to dashboard Cite

This paper provides a comprehensive derivation of the total energy equations for the atmospheric components of Earth System Models (ESMs). The assumptions and approximations made in this derivation are motivated and discussed. In particular, it is emphasized that closing the energy budget is conceptually challenging and hard to achieve in practice without resorting to ad hoc fixers. As a concrete example, the energy budget terms are diagnosed in a realistic climate simulation using a global atmosphere model. The largest total energy errors in this example are spurious dynamical core energy dissipation, thermodynamic inconsistencies (e.g., coupling parameterizations with the host model) and missing processes/terms associated with falling precipitation and evaporation (e.g., enthalpy flux between components). The latter two errors are not, in general, reduced by increasing horizontal resolution. They are due to incomplete thermodynamic and dynamic formulations. Future research directions are proposed to reconcile and improve thermodynamics formulations and conservation principles.

show abstract

Assessing Adaptive Mesh Refinement (AMR) in a Forced Shallow-Water Model with Moisture

Cited by 5 publications

References 31 publications

Topography based local spherical Voronoi grid refinement on classical and moist shallow-water finite volume models

Topography based local spherical Voronoi grid refinement on classical and moist shallow-water finite volume models

Topography-based local spherical Voronoi grid refinement on classical and moist shallow-water finite-volume models

Reconciling and Improving Formulations for Thermodynamics and Conservation Principles in Earth System Models (ESMs)

Contact Info

Product

Resources

About