Modeling the effects of gravity wave momentum deposition on the general circulation above the turbopause
Modeling the effects of gravity wave momentum deposition on the general circulation above the turbopause
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DOI：
10.1029/2008jd011132
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发表时间：
2009-04
影响因子：
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通讯作者：
Erdal Yiğit;A. Medvedev;A. Aylward;P. Hartogh;M. Harris
中科院分区：
文献类型：
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作者：
Erdal Yiğit;A. Medvedev;A. Aylward;P. Hartogh;M. Harris
[1] Yigit 等人开发的非线性谱重力波 (GW) 阻力参数化系统地解释了热层中的破裂和耗散。 (2008) 已被应用到伦敦大学学院耦合中层大气-热层-2 (CMAT2) 大气环流模型 (GCM) 中。六月至日条件下的一系列 GCM 测试研究了从低层大气向上传播的引力波的动力学作用。结果表明，引力波阻力不仅在涡轮顶以上不可忽略，而且会强烈传播到热层上部，并且在消散后，沉积的动量与离子阻力相当，至少可达 180-200 公里。热层重力波阻力的影响在冬季（南半球）尤其明显，其中较弱的西风和较强的高纬度东风得到了很好的模拟，与经验水平风模型（HWM93）一致。 F 区域的动态响应对源光谱的变化敏感。然而，中层大气 GCM 中常用的光谱相当好地再现了热层下部和上部的环流。
[1] A nonlinear spectral gravity wave (GW) drag parameterization systematically accounting for breaking and dissipation in the thermosphere developed by Yigit et al. (2008) has been implemented into the University College London Coupled Middle Atmosphere-Thermosphere-2 (CMAT2) general circulation model (GCM). The dynamical role of GWs propagating upward from the lower atmosphere has been studied in a series of GCM tests for June solstice conditions. The results suggest that GW drag is not only nonnegligible above the turbopause, but that GWs propagate strongly into the upper thermosphere, and, upon their dissipation, deposit momentum comparable to that of ion drag, at least up to 180–200 km. The effects of thermospheric GW drag are particularly noticeable in the winter (southern) hemisphere, where weaker westerlies and stronger high-latitude easterlies are simulated well, in agreement with the empirical Horizontal Wind Model (HWM93). The dynamic response in the F region is sensitive to the variations of the source spectrum. However, the spectra commonly employed in middle atmosphere GCMs reproduce the circulation both in the lower and upper thermosphere reasonably well.