Performance of the HOMME dynamical core in the aqua-planet configuration of NCAR CAM4: equatorial waves

Mishra, Saroj K.; Taylor, Mark A.; Nair, Ramachandran D.; Tufo, Henry M.; Tribbia, Joseph

doi:10.5194/angeo-29-221-2011

Cited by 9 publications

(5 citation statements)

References 12 publications

(15 reference statements)

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“…This result is in agreement with previous CAM aquaplanet simulations (Mishra et al 2011b;Rauscher et al 2013). 12g-i.…”

Section: A Equatorial Wave Activitysupporting

confidence: 93%

“…Both Williamson (2008a) and Li et al (2011) showed that precipitation extremes in aquaplanet simulations using the CAM Eulerian spectral transform dynamical core and CAM3 physics parameterization did not converge with increasing resolution and fixed physics time step. Mishra et al (2011a) used CAM4 physics and an aquaplanet to test the rainfall characteristics in an earlier version of the SE dynamical core. Mishra et al (2011a) used CAM4 physics and an aquaplanet to test the rainfall characteristics in an earlier version of the SE dynamical core.…”

Section: B Aquaplanet Experimentsmentioning

confidence: 99%

“…These values are in good agreement with the results of Mishra et al (2011a), who produced a timeaveraged, global precipitation rate of 2.95 mm day 21 in a 18 simulation using an earlier version of CAM-SE with CAM4 physics. These values are in good agreement with the results of Mishra et al (2011a), who produced a timeaveraged, global precipitation rate of 2.95 mm day 21 in a 18 simulation using an earlier version of CAM-SE with CAM4 physics.…”

Section: Cam4 Climatologymentioning

confidence: 99%

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Aquaplanet Experiments Using CAM’s Variable-Resolution Dynamical Core

et al. 2014

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A variable-resolution option has been added within the spectral element (SE) dynamical core of the U.S. Department of Energy (DOE)-NCAR Community Atmosphere Model (CAM). CAM-SE allows for static refinement via conforming quadrilateral meshes on the cubed sphere. This paper investigates the effect of mesh refinement in a climate model by running variable-resolution (var-res) simulations on an aquaplanet. The variable-resolution grid is a 28 (;222 km) grid with a refined patch of 0.258 (;28 km) resolution centered at the equator. Climatology statistics from these simulations are compared to globally uniform runs of 28 and 0.258. A significant resolution dependence exists when using the CAM version 4 (CAM4) subgrid physical parameterization package across scales. Global cloud fraction decreases and equatorial precipitation increases with finer horizontal resolution, resulting in drastically different climates between the uniform grid runs and a physics-induced grid imprinting in the var-res simulation. Using CAM version 5 (CAM5) physics significantly improves cloud scaling at different grid resolutions. Additional precipitation at the equator in the highresolution mesh results in collocated zonally anomalous divergence in both var-res simulations, although this feature is much weaker in CAM5 than CAM4. The equilibrium solution at each grid spacing within the var-res simulations captures the majority of the resolution signal of the corresponding globally uniform grids. The var-res simulation exhibits good performance with respect to wave propagation, including equatorial regions where waves pass through grid transitions. In addition, the increased frequency of high-precipitation events in the refined 0.258 area within the var-res simulations matches that observed in the global 0.258 simulations.

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“…This result is in agreement with previous CAM aquaplanet simulations (Mishra et al 2011b;Rauscher et al 2013). 12g-i.…”

Section: A Equatorial Wave Activitysupporting

confidence: 93%

Section: B Aquaplanet Experimentsmentioning

confidence: 99%

Section: Cam4 Climatologymentioning

confidence: 99%

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Aquaplanet Experiments Using CAM’s Variable-Resolution Dynamical Core

et al. 2014

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“…The SEM was chosen based on its demonstrated scalability when run as a standalone dry dynamical core (Dennis et al 2005; Bhanot et al 2008). In addition to scalability, the SEM is known to produce accurate solutions for atmospheric problems, as demonstrated first with shallow water test cases (Taylor et al 1997; Thomas and Loft 2002), three-dimensional dry dynamical test cases (Taylor et al 1998; Thomas and Loft 2005; Dennis et al 2005; Taylor et al 2007; Lauritzen et al 2010), idealized multicloud simulations (Khouider et al 2010), idealized aqua planet experiments which include full physics (Taylor et al 2008; Mishra et al 2011b,a) and realistic simulations with CAM2 physics (Wang et al 2007). A tuned version of CAM-SE simulating the Earth’s climate is evaluated by Evans et al (2011).…”

Section: Introductionmentioning

confidence: 99%

CAM-SE: A scalable spectral element dynamical core for the Community Atmosphere Model

Dennis

Edwards

Evans

et al. 2011

The International Journal of High Performance Computing Applica

334

345

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The Community Atmosphere Model (CAM) version 5 includes a spectral element dynamical core option from NCAR's High-Order Method Modeling Environment. It is a continuous Galerkin spectral finite element method designed for fully unstructured quadrilateral meshes. The current configurations in CAM are based on the cubedsphere grid. The main motivation for including a spectral element dynamical core is to improve the scalability of CAM by allowing quasi-uniform grids for the sphere that do not require polar filters. In addition, the approach provides other state-of-the-art capabilities such as improved conservation properties. Spectral elements are used for the horizontal discretization, while most other aspects of the dynamical core are a hybrid of well tested techniques from CAM's finite volume and global spectral dynamical core options. Here we first give a overview of the spectral element dynamical core as used in CAM. We then give scalability and performance results from CAM running with three different dynamical core options within the Community Earth System Model, using a pre-industrial time-slice configuration. We focus on high resolution simulations, using 1/4 degree, 1/8 degree, and T341 spectral truncation horizontal grids.

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“…Since land-atmosphere interactions and mountain effects are removed, it makes it easier to discern causes and effects in idealized process studies. As a consequence, aquaplanet simulations have become a valuable tool for evaluating and comparing different combinations of dynamical cores, model designs, parameter settings, and physical parameterizations (e.g., Williamson and Olson, 2003;Medeiros et al, 2008;Williamson, 2008b;Mishra et al, 2011b;Rauscher et al, 2013). We envision similar broad application areas for our suggested moist variant of the HS test, which is accompanied by the Fortran source code (see the Supplement).…”

Section: Introductionmentioning

confidence: 99%

A moist aquaplanet variant of the Held–Suarez test for atmospheric model dynamical cores

Thatcher

Jablonowski

2016

Geosci. Model Dev.

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Abstract. A moist idealized test case (MITC) for atmospheric model dynamical cores is presented. The MITC is based on the Held–Suarez (HS) test that was developed for dry simulations on “a flat Earth” and replaces the full physical parameterization package with a Newtonian temperature relaxation and Rayleigh damping of the low-level winds. This new variant of the HS test includes moisture and thereby sheds light on the nonlinear dynamics–physics moisture feedbacks without the complexity of full-physics parameterization packages. In particular, it adds simplified moist processes to the HS forcing to model large-scale condensation, boundary-layer mixing, and the exchange of latent and sensible heat between the atmospheric surface and an ocean-covered planet. Using a variety of dynamical cores of the National Center for Atmospheric Research (NCAR)'s Community Atmosphere Model (CAM), this paper demonstrates that the inclusion of the moist idealized physics package leads to climatic states that closely resemble aquaplanet simulations with complex physical parameterizations. This establishes that the MITC approach generates reasonable atmospheric circulations and can be used for a broad range of scientific investigations. This paper provides examples of two application areas. First, the test case reveals the characteristics of the physics–dynamics coupling technique and reproduces coupling issues seen in full-physics simulations. In particular, it is shown that sudden adjustments of the prognostic fields due to moist physics tendencies can trigger undesirable large-scale gravity waves, which can be remedied by a more gradual application of the physical forcing. Second, the moist idealized test case can be used to intercompare dynamical cores. These examples demonstrate the versatility of the MITC approach and suggestions are made for further application areas. The new moist variant of the HS test can be considered a test case of intermediate complexity.

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Performance of the HOMME dynamical core in the aqua-planet configuration of NCAR CAM4: equatorial waves

Cited by 9 publications

References 12 publications

Aquaplanet Experiments Using CAM’s Variable-Resolution Dynamical Core

Aquaplanet Experiments Using CAM’s Variable-Resolution Dynamical Core

CAM-SE: A scalable spectral element dynamical core for the Community Atmosphere Model

A moist aquaplanet variant of the Held–Suarez test for atmospheric model dynamical cores

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