Latitudinal variations observed in gravity waves with short vertical wavelengths

被引:0
作者
Alexander, MJ
Tsuda, T
Vincent, RA
机构
[1] NW Res Associates Inc, Colorado Res Associates Div, Boulder, CO 80301 USA
[2] Kyoto Univ, Radio Sci Ctr Space & Atmosphere, Kyoto, Japan
[3] Univ Adelaide, Dept Phys & Math Phys, Adelaide, SA 5005, Australia
关键词
D O I
10.1175/1520-0469(2002)059<1394:LVOIGW>2.0.CO;2
中图分类号
P4 [大气科学(气象学)];
学科分类号
0706 ; 070601 ;
摘要
Knowledge of the latitudinal variations in the occurrence of gravity waves is important for their parameterization in global models. Observations of gravity waves with short vertical scales have shown a pronounced peak in wave activity at tropical latitudes. In this paper, it is shown that such a peak may be a natural consequence of the latitudinal variation in the Coriolis parameter, which controls the lower limit for gravity-wave intrinsic frequencies. Two distinct but related effects of this parameter on observations of gravity-wave activity are explained and explored with a simple model. The results are also compared to observed latitudinal variations in gravity-wave activity. The authors formally distinguish between observed gravity-wave spectra and what is called gravity-wave "source spectra,'' the latter being appropriate for input to gravity-wave parameterizations. The results suggest that the (ω) over cap (-5/3) dependence of the gravity-wave energy spectrum commonly assumed as input to parameterizations is likely too steeply sloped. Much more shallowly sloped spectra for gravity-wave parameterization input proportional to(ω) over cap (-0.6) - (ω) over cap (-0.7) show better agreement with observations. The results also underscore the potential importance of intermittency in gravity-wave sources to the interpretation of gravity-wave observations.
引用
收藏
页码:1394 / 1404
页数:11
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