On resolution sensitivity in the Community Atmosphere Model
On resolution sensitivity in the Community Atmosphere Model
复制标题
论社区大气模型中的分辨率敏感性
DOI：
10.1002/qj.3873
复制
发表时间：
2020
影响因子：
8.9
通讯作者：
Reed, Kevin A.
中科院分区：
文献类型：
--
作者：
Herrington, Adam R.;Reed, Kevin A.
高性能计算的进步使得在越来越宽的网格分辨率范围内运行大气环流模式（AGCM）成为可能，无论是使用全球统一网格还是可变分辨率网格。原则上，这是一个令人兴奋的机会，可以在全球模式中以前所未有的细节解决大气过程和尺度，但在实践中，这种网格灵活性与长期以来一直具有AGCM特征的水平分辨率不断提高的非或弱收敛解不兼容。在社区大气模式（CAM）中，自三十多年前首次引入该模式以来，对水平分辨率的敏感性一直很强;随着分辨率的增加，大气逐渐干燥，变得不那么多云，参数化的深对流降水以层状降水为代价减少。本研究记录了一个收敛实验，使用CAM，版本6，并认为，一个统一的原因，解决动态模式的灵敏度，本地网格分辨率，反馈到其他模型组件，并解释这些强大的灵敏度分辨率。解决垂直速度与分辨率的增加幅度示出，以适应在流体静力学尺度的运动方程推导出的分析标度。垂直速度的这种趋势导致云底分解的向上水分通量增加，并通过分层降水率随分辨率的增加而平衡。补偿，更大幅度的沉降运动与分辨率先前已被证明干燥的大气和减少云层覆盖。在这里，它表明，从层状云的形成和更大的沉降干燥的凝结加热的增加有助于增加大气稳定性与分辨率，减少参数化对流的活动。在AGCM中恢复收敛解的任何努力中，都不能忽视用本地网格分辨率改变垂直速度场的影响，特别是尺度感知物理参数化的发展。
Advances in high‐performance computing make it possible to run atmospheric general circulation models (AGCMs) over an increasingly wider range of grid resolutions, using either globally uniform or variable‐resolution grids. In principle, this is an exciting opportunity to resolve atmospheric process and scales in a global model and in unprecedented detail, but in practice this grid flexibility is incompatible with the non‐ or weakly converging solutions with increasing horizontal resolution that have long characterized AGCMs. In the the Community Atmosphere Model (CAM), there are robust sensitivities to horizontal resolution that have persisted since the model was first introduced over thirty years ago; the atmosphere progressively dries and becomes less cloudy with resolution, and parametrized deep convective precipitation decreases at the expense of stratiform precipitation. This study documents a convergence experiment using CAM, version 6, and argues that a unifying cause, the sensitivity of resolved dynamical modes to native grid resolution, feeds back into other model components and explains these robust sensitivities to resolution. The increasing magnitudes of resolved vertical velocities with resolution are shown to fit an analytic scaling derived for the equations of motion at hydrostatic scales. This trend in vertical velocities results in an increase in resolved upward moisture fluxes at cloud base, balanced by an increase in stratiform precipitation rates with resolution. Compensating, greater magnitude subsiding motion with resolution has previously been shown to dry out the atmosphere and reduce cloud cover. Here, it is shown that both the increase in condensational heating from stratiform cloud formation and greater subsidence drying contribute to an increase in atmospheric stability with resolution, reducing the activity of parametrized convection. The impact of changing the vertical velocity field with native grid resolution cannot be ignored in any effort to recover convergent solutions in AGCMs, and, in particular, the development of scale‐aware physical parametrizations.
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影响因子：
8.9
作者：
D. Williamson
通讯作者：
D. Williamson
NCAR 社区气候模型 (CCM2) 对水平分辨率的气候敏感性
DOI：
--
发表时间：
1995
期刊：
影响因子：
--
作者：
D. Williamson;J. Kiehl;J. Hack
通讯作者：
J. Hack
灰色区域的垂直速度
影响因子：
6.8
作者：
N. Jeevanjee
通讯作者：
N. Jeevanjee
社区大气模型对跨静水分辨率的近网格尺度强迫响应的理想化测试
影响因子：
6.8
作者：
A. Herrington;Kevin A. Reed
通讯作者：
Kevin A. Reed
影响因子：
3.1
作者：
R. Plant;G. Craig
通讯作者：
R. Plant;G. Craig