Curl-Free Pressure Gradients over Orography in a Solution of the Fully Compressible Euler Equations with Implicit Treatment of Acoustic and Gravity Waves
Curl-Free Pressure Gradients over Orography in a Solution of the Fully Compressible Euler Equations with Implicit Treatment of Acoustic and Gravity Waves
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DOI：
10.1175/mwr-d-14-00054.1
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发表时间：
2014-12
影响因子：
3.2
通讯作者：
H. Weller;A. Shahrokhi
中科院分区：
文献类型：
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作者：
H. Weller;A. Shahrokhi
陡峭的地形会引起大气模式的解的噪声和不稳定性。本文介绍了一种新的地形流模拟技术，它保证了任意网格上的无旋梯度，这意味着压力梯度项不是一个虚假的涡源。这种模仿属性导致更好的流体静力学平衡和更好的能量守恒的测试情况下，使用地形跟随网格。无旋梯度是通过使用协变分量的速度在地形，而不是通常的水平和垂直components.In此外，重力和声波被隐式处理，而不需要的平均值和扰动变量或流体静力学的参考配置文件。这使得一个简单的隐式处理重力wave.Results的描述，提出了一个休息的大气地形和无旋压力梯度制剂是有利的。重力波在地形上的传播结果对地形的位置不敏感。
AbstractSteep orography can cause noisy solutions and instability in models of the atmosphere. A new technique for modeling flow over orography is introduced that guarantees curl-free gradients on arbitrary grids, implying that the pressure gradient term is not a spurious source of vorticity. This mimetic property leads to better hydrostatic balance and better energy conservation on test cases using terrain-following grids. Curl-free gradients are achieved by using the covariant components of velocity over orography rather than the usual horizontal and vertical components.In addition, gravity and acoustic waves are treated implicitly without the need for mean and perturbation variables or a hydrostatic reference profile. This enables a straightforward description of the implicit treatment of gravity waves.Results are presented of a resting atmosphere over orography and the curl-free pressure gradient formulation is advantageous. Results of gravity waves over orography are insensitive to the placement of t...