A Multiscale Nonhydrostatic Atmospheric Model Using Centroidal Voronoi Tesselations and C-Grid Staggering

Skamarock, William C.; Klemp, Joseph B.; Duda, Michael; Fowler, Laura D.; Park, Sang Hun; Ringler, Todd D.

doi:10.1175/mwr-d-11-00215.1

Cited by 474 publications

(458 citation statements)

References 31 publications

(74 reference statements)

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“…Currently, the MPAS dycore only works with CAM4 physics, although a new, non-hydrostatic version with CAM5 physics is currently in development (Skamarock et al, 2012b), and the SE dycore has not been extensively tested with the CAM5 physics. The apparent improvements in the scale-aware behavior of the CAM5 physics package, combined with the fact that it is now the core atmospheric model for the Community Earth System Model package, make it the logical alternative to CAM4 for variable-mesh modeling.…”

Section: Discussionmentioning

confidence: 99%

“…This expectation is supported by the fact that the slopes are relatively consistent within dycore groups. For example, all of the MPAS-A simulations, which use high-order transport discretizations on a set of spherical centroidal Voronoi tessellations (Skamarock et al, 2012a), have slopes of relatively low magnitude for cloud areas smaller than the scale-break point. In contrast, the finite-volume simulations, which use second-order transport discretizations on a regular grid (Neale et al, 2010), have much larger slopes for clouds areas below the scalebreak point.…”

Section: Precipitation Scalingmentioning

confidence: 99%

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Observed Scaling in Clouds and Precipitation and Scale Incognizance in Regional to Global Atmospheric Models

O’Brien¹,

Li²,

Collins

et al. 2013

J. Climate

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We use observations of robust scaling behavior in clouds and precipitation to derive constraints on how partitioning of precipitation should change with model resolution. Our analysis indicates that 90-99% of stratiform precipitation should occur in clouds that are resolvable by contemporary climate models (e.g., with 200 km or finer grid spacing). Furthermore, this resolved fraction of stratiform precipitation should increase sharply with resolution, such that effectively all stratiform precipitation should be resolvable above scales of ∼50 km. We show that the Community Atmosphere Model (CAM) and the Weather Research and Forecasting (WRF) model also exhibit the robust cloud and precipitation scaling behavior that is present in observations, yet the resolved fraction of stratiform precipitation actually decreases with increasing model resolution. A suite of experiments with multiple dynamical cores provides strong evidence that this 'scale-incognizant' behavior originates in one of the CAM4 parameterizations. An additional set of sensitivity experiments rules out both convection parameterizations, and by a process of elimination these results implicate the stratiform cloud and precipitation parameterization. Tests with the CAM5 physics package show improvements in the resolution-dependence of resolved cloud fraction and resolved stratiform precipitation fraction.

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Section: Discussionmentioning

confidence: 99%

Section: Precipitation Scalingmentioning

confidence: 99%

Observed Scaling in Clouds and Precipitation and Scale Incognizance in Regional to Global Atmospheric Models

O’Brien¹,

Li²,

Collins

et al. 2013

J. Climate

Self Cite

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show abstract

“…An example of such efforts is the ongoing work to extend CMAQ to hemispheric scales (Mathur et al, 2017) while future 10 work may be directed at implementing treatment for atmospheric chemistry in next-generation global dynamic models with variable grid resolution features such as the Model for Prediction Across Scales (MPAS) (Skamarock et al, 2012) and the Finite-Volume Cubed-Sphere Dynamical Core (FV3) model (Harris and Lin, 2013). Furthermore, the results from the bounding sensitivity simulations suggest that coordinated evaluation and intercomparison activities for ozone dry deposition would be valuable in better constraining simulated ozone budgets.…”

mentioning

confidence: 99%

Impacts of Different Characterizations of Large-Scale Background on Simulated Regional-Scale Ozone Over the Continental United States

Hogrefe¹,

Liu²,

Pouliot³

et al. 2017

Preprint

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Abstract. This study analyzes simulated regional-scale ozone burdens both near the surface and aloft, estimates process contributions to these burdens, and calculates the sensitivity of the simulated regional-scale ozone burden to several key model 15 inputs with a particular emphasis on boundary conditions derived from hemispheric or global scale models. The Community Multiscale Air Quality (CMAQ) model simulations supporting this analysis were performed over the continental U.S. for the Hypothetical bounding scenarios were performed to quantify the effects of emissions, boundary conditions, and ozone dry deposition on the simulated ozone burden. Analysis of these simulations confirms that the characterization of ozone outside the regional-scale modeling domain can have a profound impact on simulated regional-scale ozone. This was further investigated by using data from four hemispheric or global modeling systems (Chemistry -Integrated Forecasting Model (C-25 IFS), CMAQ extended for hemispheric applications (H-CMAQ), GEOS-Chem, and AM3) to derive alternate boundary conditions for the regional-scale CMAQ simulations. The regional-scale CMAQ simulations using these four different boundary conditions showed that the largest ozone abundance in the upper layers was simulated when using boundary conditions from GEOS-Chem, followed by the simulations using C-IFS, AM3, and H-CMAQ boundary conditions, consistent with the analysis of the ozone fields from the global models along the CMAQ boundaries. Using boundary conditions from 30 AM3 yielded higher springtime ozone columns burdens in the mid-and lower troposphere compared to boundary conditions from the other models. For surface ozone, the differences between the AM3-driven CMAQ simulations and the CMAQ simulations driven by other large-scale models are especially pronounced during spring and winter where they can reach more Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-676 Manuscript under review for journal Atmos. Chem. Phys. Discussion started: 8 August 2017 c Author(s) 2017. CC BY 4.0 License. 2 than 10 ppb for seasonal mean ozone mixing ratios and as much as 15 ppb for domain-averaged daily maximum 8-hr average ozone on individual days. In contrast, the differences between the C-IFS, GEOS-Chem, and H-CMAQ driven regional-scale CMAQ simulations are typically smaller. Comparing simulated surface ozone mixing ratios to observations and computing seasonal and regional model performance statistics revealed that boundary conditions can have a substantial impact on model performance. Further analysis showed that boundary conditions can affect model performance across the entire range of the 5 observed distribution, although the impacts tend to be lower during summer and for the very highest observed percentiles. The results are discussed in the context of future model development and analysis opportunities.

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“…With the recent developments of global models with ''very'' high resolution (grid-spacings O 10 ð Þkm), SE methods are now being used also for global NWP: the MPAS model [89] has adopted the SE approach (as described in [56]) based directly on the successful experiences with the 3-stage 3rd-order RK-based SE approach in WRF. The high resolution global non-hydrostatic model, NICAM, also uses a RK-based SE approach (with options for 2nd-or 3rd-order RK schemes) [82,83].…”

Section: Split-explicit Schemesmentioning

confidence: 99%

Current and Emerging Time-Integration Strategies in Global Numerical Weather and Climate Prediction

Mengaldo

Wyszogrodzki

Diamantakis

et al. 2018

Arch Computat Methods Eng

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The continuous partial differential equations governing a given physical phenomenon, such as the Navier-Stokes equations describing the fluid motion, must be numerically discretized in space and time in order to obtain a solution otherwise not readily available in closed (i.e., analytic) form. While the overall numerical discretization plays an essential role in the algorithmic efficiency and physically-faithful representation of the solution, the time-integration strategy commonly is one of the main drivers in terms of cost-to-solution (e.g., time-or energy-to-solution), accuracy and numerical stability, thus constituting one of the key building blocks of the computational model. This is especially true in time-critical applications, including numerical weather prediction (NWP), climate simulations and engineering. This review provides a comprehensive overview of the existing and emerging time-integration (also referred to as time-stepping) practices used in the operational global NWP and climate industry, where global refers to weather and climate simulations performed on the entire globe. While there are many flavors of time-integration strategies, in this review we focus on the most widely adopted in NWP and climate centers and we emphasize the reasons why such numerical solutions were adopted. This allows us to make some considerations on future trends in the field such as the need to balance accuracy in time with substantially enhanced time-to-solution and associated implications on energy consumption and running costs. In addition, the potential for the co-design of time-stepping algorithms and underlying high performance computing hardware, a keystone to accelerate the computational performance of future NWP and climate services, is also discussed in the context of the demanding operational requirements of the weather and climate industry.

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A Multiscale Nonhydrostatic Atmospheric Model Using Centroidal Voronoi Tesselations and C-Grid Staggering

Cited by 474 publications

References 31 publications

Observed Scaling in Clouds and Precipitation and Scale Incognizance in Regional to Global Atmospheric Models

Observed Scaling in Clouds and Precipitation and Scale Incognizance in Regional to Global Atmospheric Models

Impacts of Different Characterizations of Large-Scale Background on Simulated Regional-Scale Ozone Over the Continental United States

Current and Emerging Time-Integration Strategies in Global Numerical Weather and Climate Prediction

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