Simulations of Stratus Clouds over Eastern China in CAM5: Sources of Errors

Zhang, Yi; Chen, Haoming; Yu, Rucong

doi:10.1175/jcli-d-14-00350.1

Cited by 10 publications

(7 citation statements)

References 60 publications

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“…5.2). A Two-step Shape-Preserving Advec-6328 Y. Zhou et al: GRIST-A20.9 tion Scheme (TSPAS; Zhang et al, 2017;Yu, 1994) is also a major option for tracer transport (as in Sect. 5.1).…”

Section: Model Framework and Dynamicsmentioning

confidence: 99%

Configuration and evaluation of a global unstructured mesh atmospheric model (GRIST-A20.9) based on the variable-resolution approach

Zhou

Zhang

et al. 2020

Geosci. Model Dev.

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Abstract. Targeting a long-term effort towards a variable-resolution (VR) global weather and climate model, this study systematically configures and evaluates an unstructured mesh atmospheric model based on the multiresolution approach. The model performance is examined from dry dynamics to simple physics and full physics scenarios. In the dry baroclinic wave test, the VR model reproduces comparable fine-scale structures in the refined regions as a fine-resolution quasi-uniform (QU) mesh model. The mesh transition zone does not adversely affect the wave pattern. Regional kinetic energy spectra show that the fine-scale resolving ability improves as the fine resolution increases. Compared to a QU counterpart that has equivalent degrees of freedom, the VR model tends to increase the global errors, but the errors can be reduced when the resolution of the coarse region is increased. The performance over the coarse region is generally close to that of a low-resolution QU counterpart. Two multi-region refinement approaches, the hierarchical and polycentric refinement modes, further validate the model performance under the multiresolution refinement. Activating hyperdiffusion for horizontal velocity is helpful with respect to VR modeling. An idealized tropical cyclone test is further used to examine its ability to resolve fine-scale structures. In the simple physics environment, the VR model can have the tropical cyclone stably pass the transition zone in various configurations. A series of sensitivity tests examines the model performance in a hierarchical refinement mode. The simulations exhibit consistency even when the VR mesh is slightly perturbed by one of the three parameters that control the density function. The tropical cyclone, starting from the second refinement region and passing through the inner transition zone, gets intensified and covers a smaller area in the refined regions. Such variations are consistent with the behavior that one may observe when uniformly refining the QU mesh. In the full physics environment with a highly variable mesh that reaches sub-10 km resolution, the VR model also produces a reasonable evolution for the tropical cyclone. The explicit diffusion shows its usefulness in terms of suppressing some unrealistic isolated-scale structures that are far away from the initial vortex and does not adversely affect the physically important object. The fine-scale structure is determined mainly by the fine-resolution area, although the systems may have larger differences before they move into the fine-resolution area. Altogether, this work demonstrates that the multiresolution configuration is a reliable and economic alternative to high-resolution global modeling. The adverse impact due to mesh transition and the coarse region can be controlled well.

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“…5.2). A Two-step Shape-Preserving Advec-6328 Y. Zhou et al: GRIST-A20.9 tion Scheme (TSPAS; Zhang et al, 2017;Yu, 1994) is also a major option for tracer transport (as in Sect. 5.1).…”

Section: Model Framework and Dynamicsmentioning

confidence: 99%

Configuration and evaluation of a global unstructured mesh atmospheric model (GRIST-A20.9) based on the variable-resolution approach

Zhou

Zhang

et al. 2020

Geosci. Model Dev.

Self Cite

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show abstract

“…In addition, this model uses a shape-preserving, but not mass-conserving, semi-lagrangian transport (SLT) method Rasch 1989, 1994) to solve the advection (transport) equation. Zhang et al (2015) compared the simulated local climate over eastern China between the spectral and FV CAM5 in several aspects (e.g., clouds and circulations). The two models generally produce similar climate except for some minor regional differences.…”

Section: Modelsmentioning

confidence: 99%

Impact of moisture divergence on systematic errors in precipitation around the Tibetan Plateau in a general circulation model

Zhang

2016

Clim Dyn

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“…For each year between 2008-2012, we initialized the model using the ERA-interim reanalysis data [32] at 00:00 UTC on 31 May. The initialization method is to use the atmospheric state (zonal and meridional winds, temperature, moisture, and surface pressure) in the reanalysis data to replace the state in the initial data (see details in [33]). The model is then continuously integrated over the entire June-July-August (JJA) months.…”

Section: Of 14mentioning

confidence: 99%

“…In this manner, we may construct a five-year JJA climate, while avoiding a five-year continuous integration. Previous studies [33][34][35] have suggested that utilizing the ensemble of discontinuous runs is an efficient approach for comparing the modeling differences, especially for the fast moist processes in the model climate. Note that all of the results shown in this paper come from the 1 • -resolution simulations.…”

Section: Of 14mentioning

confidence: 99%

Robust Nocturnal and Early Morning Summer Rainfall Peaks over Continental East Asia in a Global Multiscale Modeling Framework

2019

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The diurnal cycle of convection and precipitation is an important atmospheric feature. It also poses a great challenge to global numerical atmospheric modeling. Over continental East Asia, most global models cannot well capture the nocturnal and early morning peaks of summer rainfall. This problem may lead to dry biases and limit the modeling skills. This study investigates this problem using a global multiscale modeling framework (Super-Parameterized CAM5; SPCAM5). The nocturnal and early morning peaks, which are almost absent in CAM5 and a coarser-resolution SPCAM5, can be successfully captured by SPCAM5 with a moderate increase in the horizontal resolution. On the lee side of the Tibetan Plateau, SPCAM5 generates robust eastward propagating rainfall signals, which correspond to the moving convective systems, as revealed by the heating and drying profiles. Over the eastern plain of China, the early morning peaks become more evident, corresponding to a stratiform-type heating structure in the midlevel. A sensitivity experiment with altered grid-scale forcing also suggests the important preconditioning role of the vertical moisture advection in regulating the early morning peaks. These results highlight the added value of representing multiscale processes to the successful simulation of the diurnal cycle over continental East Asia.

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Simulations of Stratus Clouds over Eastern China in CAM5: Sources of Errors

Cited by 10 publications

References 60 publications

Configuration and evaluation of a global unstructured mesh atmospheric model (GRIST-A20.9) based on the variable-resolution approach

Configuration and evaluation of a global unstructured mesh atmospheric model (GRIST-A20.9) based on the variable-resolution approach

Impact of moisture divergence on systematic errors in precipitation around the Tibetan Plateau in a general circulation model

Robust Nocturnal and Early Morning Summer Rainfall Peaks over Continental East Asia in a Global Multiscale Modeling Framework

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