Comparison of horizontal velocity spectra derived from chaff rockets with saturation models
文献类型：期刊论文
| 作者 | Wu, Y. F. ; Xu, J. Y. |
| 刊名 | Journal of Geophysical Research-Atmospheres
 |
| 出版日期 | 2006 |
| 卷号 | 111期号:D13页码:D13109 |
| ISSN号 | 0148-0227 |
| 关键词 | gravity-wave spectrum starfire optical-range lower thermosphere middle atmosphere mesopause region testing theories number spectra lower stratosphere mac epsilon foil chaff |
| 通讯作者 | 北京8701信箱 |
| 英文摘要 | We present vertical wave number spectra of wind fluctuations using data with a height resolution of 25 m observed near the mesopause by 64 chaff rockets. Direct measurement of Brunt-Vaisala frequency allows accurate calculations of spectral amplitude and local Richardson number. Individual vertical wave number spectra reveal considerable variability in both slope and amplitude, which is not consistent with the predictions of various saturation models. Mean vertical wave number spectra observed at different locations and seasons show great similarities. While the spectral amplitude predicted by the linear saturation model or saturated-cascade model is comparable to the spectral amplitude of the observed mean spectrum, those spectral amplitudes predicted by other saturation models are larger than the observed mean amplitude within a factor of 3. However, mean vertical wave number spectra observed at 69 degrees N exhibit significant seasonal variation with a shallower slope of - 2.40 and a larger spectral amplitude of 2.6 x 10(5) (m(2)/s(2))/(cyc/m) at m = 1/(4 km) in winter compared to that spectrum observed in summer. Very large mean wind shears, as high as 42 - 77 m/s/km, are observed to be present at several heights near the mesopause. Such strong mean shear profiles, together with the Brunt-Vaisala frequency squared N-2 profiles, act collectively to produce dynamical instability regions of local Richardson number Ri smaller than 0.25. These regions are found to correlate well with the saturated gravity wave spectra. In contrast, the stable region of local Richardson number Ri larger than 0.4 observed at high latitude in winter is found to associate with an unsaturated gravity wave spectrum. |
| 学科主题 | 空间物理 |
| 收录类别 | SCI |
| 原文出处 | http://www.agu.org/pubs/crossref/2006/2005JD006065.shtml |
| 语种 | 英语 |
| 源URL | [http://ir.cssar.ac.cn/handle/122/1056]  |
| 专题 | 国家空间科学中心_空间科学部 |
| 推荐引用方式 GB/T 7714 | Wu, Y. F.,Xu, J. Y.. Comparison of horizontal velocity spectra derived from chaff rockets with saturation models[J]. Journal of Geophysical Research-Atmospheres,2006,111(D13):D13109. |
| APA | Wu, Y. F.,&Xu, J. Y..(2006).Comparison of horizontal velocity spectra derived from chaff rockets with saturation models.Journal of Geophysical Research-Atmospheres,111(D13),D13109. |
| MLA | Wu, Y. F.,et al."Comparison of horizontal velocity spectra derived from chaff rockets with saturation models".Journal of Geophysical Research-Atmospheres 111.D13(2006):D13109. |
入库方式： OAI收割
来源：国家空间科学中心
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