Resolution and domain‐size sensitivity in implicit large‐eddy simulation of the stratocumulus‐topped boundary layer
Resolution and domain‐size sensitivity in implicit large‐eddy simulation of the stratocumulus‐topped boundary layer
复制标题
层积云顶边界层隐式大涡模拟中的分辨率和域尺寸敏感性
DOI：
10.1002/2015ms000572
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发表时间：
2016
影响因子：
6.8
通讯作者：
W. Grabowski
中科院分区：
文献类型：
--
作者：
J. Pedersen;S. Malinowski;W. Grabowski
作为测量的补充，数值模拟有助于更好地理解层积云顶边界层（STBL）中复杂的湍流过程。由于有限的计算资源，模拟通常以太粗糙的分辨率运行，以解决云顶湍流的细节，并且可能在计算域太小，无法考虑边界层环流的最大尺度。这些缺陷的影响尚未完全了解。在这里，分辨率/各向异性的计算网格和区域大小的影响，在欠分辨隐式大涡模拟的STBL的研究。所进行的模拟是基于DYCOMS-II活动首次研究飞行的数据。关于云量和域平均液态水路径，发现水平/垂直网格间距为35/5 m、70/10 m和105/15 m的模拟与测量结果的一致性优于计算成本更高的各向同性网格箱模拟，例如，网格间距为10/10 m或15/15 m。虽然减小垂直网格间距可以更有代表性地模拟STBL和自由对流层之间的薄湍流稳定分层界面层，但粗化水平分辨率可以抑制该区域的垂直速度波动，并模拟云顶附近稳定分层小尺度湍流的各向异性。计算域的大小被发现几乎没有影响平均云的属性。然而，将其从3.5×3.5 km 2增加到14×14 km 2确实导致出现更大的相干上升气流结构。将其进一步增加到21×21 km 2表明上升气流的大小几乎没有增加。
As a complement to measurements, numerical modeling facilitates improved understanding of the complex turbulent processes in the stratocumulus‐topped boundary layer (STBL). Due to limited computational resources simulations are often run at too coarse resolutions to resolve details of cloud‐top turbulence and potentially in computational domains too small to account for the largest scales of boundary layer circulations. The effects of such deficiencies are not fully understood. Here the influence of resolution/anisotropy of the computational grid and domain size in under‐resolved implicit large‐eddy simulation of the STBL is investigated. The performed simulations are based on data from the first research flight of the DYCOMS‐II campaign. Regarding cloud cover and domain‐averaged liquid water path, simulations with horizontal/vertical grid spacing of 35/5 m, 70/10 m, and 105/15 m are found to agree better with measurements than more computationally expensive simulations with isotropic grid boxes, e.g., with 10/10 m or 15/15 m grid spacing. While decreasing the vertical grid spacing allows more representative simulation of the thin, turbulent, stably stratified interfacial layer between the STBL and the free troposphere, coarsening the horizontal resolution dampens vertical velocity fluctuations in this region and mimics the observed anisotropy of stably stratified small‐scale turbulence near the cloud top. The size of the computational domain is found to have almost no impact on mean cloud properties. However, increasing it from 3.5×3.5 km2 to 14×14 km2 does lead to the occurrence of larger coherent updraft structures. Increasing it further to 21×21 km2 shows little or no increase in the updraft size.
模拟重力波对 VOCALS-UK 期间观察到的层积云的影响
影响因子：
6.3
作者：
Connolly P
通讯作者：
Connolly P