An Idealized Test of the Response of the Community Atmosphere Model to Near‐Grid‐Scale Forcing Across Hydrostatic Resolutions
An Idealized Test of the Response of the Community Atmosphere Model to Near‐Grid‐Scale Forcing Across Hydrostatic Resolutions
复制标题
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
DOI：
10.1002/2017ms001078
复制
发表时间：
2018
影响因子：
6.8
通讯作者：
Kevin A. Reed
中科院分区：
文献类型：
--
作者：
A. Herrington;Kevin A. Reed
一组理想化的实验开发使用社区大气模式（CAM），以了解垂直速度响应减少强迫尺度，这是已知的发生时，模型的水平分辨率增加。试验由一组上升气泡实验组成，其中气泡的水平半径和模型网格间距同时减小。该测试是与水分，通过纳入不同复杂性的潮湿物理例程，虽然对流计划没有考虑。结果证实，CAM中的垂直速度是一阶的，与水平强迫尺度的倒数成比例，这与干运动方程的尺度分析一致。相比之下，实验中，湿物理例程和动态核心之间的耦合时间步长（即，“物理”时间步长）被松弛回到更常规的值，导致在高分辨率下严重衰减的垂直运动，降低了缩放。一组使用不同物理时间步长的水行星模拟被发现与理想化实验的结果一致。
A set of idealized experiments are developed using the Community Atmosphere Model (CAM) to understand the vertical velocity response to reductions in forcing scale that is known to occur when the horizontal resolution of the model is increased. The test consists of a set of rising bubble experiments, in which the horizontal radius of the bubble and the model grid spacing are simultaneously reduced. The test is performed with moisture, through incorporating moist physics routines of varying complexity, although convection schemes are not considered. Results confirm that the vertical velocity in CAM is to first‐order, proportional to the inverse of the horizontal forcing scale, which is consistent with a scale analysis of the dry equations of motion. In contrast, experiments in which the coupling time step between the moist physics routines and the dynamical core (i.e., the “physics” time step) are relaxed back to more conventional values results in severely damped vertical motion at high resolution, degrading the scaling. A set of aqua‐planet simulations using different physics time steps are found to be consistent with the results of the idealized experiments.