Computational performance of ultra-high-resolution capability in the Community Earth System Model

Dennis, John M.; Vertenstein, Mariana; Worley, Patrick H; Mirin, A.A.; Craig, Anthony P; Jacob, Robert; Mickelson, Sheri

doi:10.1177/1094342012436965

Cited by 64 publications

(38 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This has important implications for the software design of climate models. Scalability to large number of processors, at least tens of thousands, is necessary to fully utilize the most recent hardware designs (Dennis et al 2012b). Scalability to 100,000 processor cores or more will likely be indispensable in the not too distant future to fully exploit manycore chip based machines (Wehner et al 2011).…”

Section: Computational Performance Issues Analysis and Scalabilitymentioning

confidence: 99%

High-Resolution Multi-decadal Simulation of Tropical Cyclones

Wehner

Reed

Zarzycki

2017

Hurricanes and Climate Change

View full text Add to dashboard Cite

Recent advances in high-performance computing technologies are enabling multiple climate modeling groups to perform global multi-decadal simulations at tropical cyclone-permitting resolutions. This chapter discusses the developing state of the art of such high-resolution modeling. These global atmospheric models, with horizontal resolutions in the 10-50 km range, simulate strong gradients in temperature and moisture far more realistically than contemporary mainstream climate models at coarser resolution. With these models, simulated tropical cyclones exhibit a surprising degree of realism in terms of both the physical characteristics of individual storms and their long-term statistical behavior. Experience with the Community Atmospheric Model version 5 is used as an example to demonstrate the strengths and weaknesses of this new class of climate models.

show abstract

Section: Computational Performance Issues Analysis and Scalabilitymentioning

confidence: 99%

High-Resolution Multi-decadal Simulation of Tropical Cyclones

Wehner

Reed

Zarzycki

2017

Hurricanes and Climate Change

View full text Add to dashboard Cite

show abstract

“…As computing resources increase, climate models have been pushed to ever higher resolutions (Dennis et al, 2012b), but Williamson (2008), Li et al (2011a), and Williamson (2012) provide recent examples of studies showing that some aspects of model climatology do not converge as resolution increases. This lack of convergence is problematic because climate change impact studies often require climatic information at the small scales characteristic of, for example, a single watershed (Kanamitsu and Kanamaru, 2007;Caldwell et al, 2009).…”

Section: Introductionmentioning

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

View full text Add to dashboard Cite

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.

show abstract

“…The global reduction, which is needed by the inner products of vectors, is even more costly (Hu et al, 2013). Worley et al (2011) and Dennis et al (2012) specifically indicated that the global reduction in the POP's barotropic solver is the main scaling bottleneck for the high-resolution ocean simulation. Figure 3 confirms that the percentage of execution time for the barotropic mode in 0.1 • POP indeed increases with an increasing number of processor cores on Yellowstone.…”

Section: Barotropic Solversmentioning

confidence: 99%

“…Using the EVP preconditioner, P-CSI can accelerate the barotropic calculation from 6.2 SYPD (simulated years per wall-clock day) to 10.5 SYPD on 16 875 cores. Dennis et al (2012) indicated that 5 simulated years per wall-clock day is the minimum requirement to run long-term climate simulations. In Sect.…”

Section: Overall Performance Of P-csimentioning

confidence: 99%

P-CSI v1.0, an accelerated barotropic solver for the high-resolution ocean model component in the Community Earth System Model v2.0

Tang

Tseng

et al. 2016

Geosci. Model Dev.

View full text Add to dashboard Cite

Abstract. In the Community Earth System Model (CESM), the ocean model is computationally expensive for highresolution grids and is often the least scalable component for high-resolution production experiments. The major bottleneck is that the barotropic solver scales poorly at high core counts. We design a new barotropic solver to accelerate the high-resolution ocean simulation. The novel solver adopts a Chebyshev-type iterative method to reduce the global communication cost in conjunction with an effective block preconditioner to further reduce the iterations. The algorithm and its computational complexity are theoretically analyzed and compared with other existing methods. We confirm the significant reduction of the global communication time with a competitive convergence rate using a series of idealized tests. Numerical experiments using the CESM 0.1 • global ocean model show that the proposed approach results in a factor of 1.7 speed-up over the original method with no loss of accuracy, achieving 10.5 simulated years per wall-clock day on 16 875 cores.

show abstract

Computational performance of ultra-high-resolution capability in the Community Earth System Model

Cited by 64 publications

References 20 publications

High-Resolution Multi-decadal Simulation of Tropical Cyclones

High-Resolution Multi-decadal Simulation of Tropical Cyclones

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

P-CSI v1.0, an accelerated barotropic solver for the high-resolution ocean model component in the Community Earth System Model v2.0

Contact Info

Product

Resources

About