DOI: 10.1029/2017JD027974
Scopus记录号: 2-s2.0-85053426328
论文题名: Numerical Modeling of the Excitation, Propagation, and Dissipation of Primary and Secondary Gravity Waves during Wintertime at McMurdo Station in the Antarctic
作者: Vadas S.L. ; Becker E.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2018
卷: 123, 期: 17 起始页码: 9326
结束页码: 9369
语种: 英语
英文关键词: Antarctica
; gravity waves
; mountain waves
; secondary gravity waves
; wave dissipation
英文摘要: We analyze the results of the gravity wave (GW)-resolving, high-resolution Kühlungsborn Mechanistic general Circulation Model in July at McMurdo Station (166.69°E and 77.84°S), where strong downslope eastward winds create strong mountain wave (MW) events. These MWs have horizontal wavelengths of λH≃230 km, propagate to z∼ 40–60 km, and can have upward phases in time if the eastward wind accelerates in time. Additionally, inertia-GWs (IGWs) with λH∼ 500–800 km and ground-based periods of τr∼ 5–6 hr are generated in the troposphere from unbalanced, large-scale flow. The density-scaled GW amplitudes are ∼10 times smaller at z∼ 80–100 km than at z < 50 km because of severe wave dissipation. “Fishbone” structures are seen at z∼ 30–60 km with upward (downward) phases in time below (above) the “knee” at zknee. We horizontally filter the perturbations to isolate the GWs in a fishbone structure for a particular MW event. We find that these GWs have strikingly similar parameters below and above zknee=46 km, with ground-based horizontal phase speeds of cH∼ 40–60 m/s, τr∼ 9–10 hr, λH∼ 1,600–2,050 km, vertical wavelengths of λz∼ 18–25 km, and azimuths of Υ= 145° –151° east of north. We show that these are secondary GWs excited by a body force at zknee created by MW dissipation approximately 400 km northwest of McMurdo 2.5 hr earlier and that the secondary GW scales and propagation directions are consistent with this force. Importantly, we show that most of the GWs at z > 70 km are secondary GWs not primary GWs from the troposphere. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113186
Appears in Collections: 气候减缓与适应
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作者单位: Northwest Research Associates, Boulder, CO, United States; Leibniz Institute of Atmospheric Physics, Kühlungsborn, Germany
Recommended Citation:
Vadas S.L.,Becker E.. Numerical Modeling of the Excitation, Propagation, and Dissipation of Primary and Secondary Gravity Waves during Wintertime at McMurdo Station in the Antarctic[J]. Journal of Geophysical Research: Atmospheres,2018-01-01,123(17)