Atmospheric Gravity Waves
Atmospheric gravity waves, often also called internal waves, exist in
layered atmospheres. They either occur as quasi-periodic waves,
solitary waves or undular bores. They are often generated behind
mountain ranges in which case they are called lee waves. In the
steady state lee waves are stationary with respect to the terrain
feature, but they are propagating relative to the mean air flow above
the earth surface. Lee waves are very common in visible remote sensing
imagery where they manifest themselves as wave-like cloud patterns.
However, they also can manifest themselves on the sea surface since
they are associated with varying wind speed at the sea surface and
thus a varying short-scale sea surface roughness.
Fig.: A linear gravity wave propagating from left to right in a
three-layer atmosphere. (left) Assumed height profile of potential
temperature for a stably stratified three-layer atmosphere. (middle)
isolines of potential temperature (dotted lines), streamlines (dashed
lines), and direction of the wind velocity fluctuations at the sea
surface (arrows at the bottom). (right) Amplitudes of the wind speed
fluctuations in the direction of the wave propagation and in the
vertical direction as a function of height.
(Reproduced from Alpers and Stilke, 1996)
Alpers, W. & Stilke, G., Observation of nonlinear wave disturbance in
the marine atmosphere by the synthetic aperture radar aboard the ERS 1
satellite. J. Geophys. Res., 101, No. C3, 6513-6525
Christie, D.R., Long nonlinear waves in the lower atmosphere,
J. Atmos. Sci., 46, 1462-1491 (1989).
Clark, T.L., Hauf, T. & Kuettner, J.P., Convectively forced internal
gravity waves: Results from two-dimensional numerical experiments,
Quarterly Journal of the Royal Meteorology Society, 112,
Crook, N.A., Trapping of low-level internal gravity waves,
J. Atmos. Sci., 45, 1533-1541 (1988).
Drake, V.A., Solitary wave disturbances of the nocturnal boundary
layer revealed by radar observations of migrating insects, Boundary
Layer Meteorol., 31, 269-286 (1985).
Fritz, S., The significance of mountain lee waves as seen from
satellite pictures, J. of Applied Meteorol., 4, 31-37
Gossard, E.E., Richer, J.H. & Atlas, D., Internal waves in the
atmosphere from high-resolution radar measurements,
J. Geophys. Res., 75, 3523-3536 (1970).
Menhofer A., Smith, R.K., Reeder, M.J. & Christie, D.R.,
"Morning-glory" disturbances and the environment in which they
propagate. J. Atm. Sci., 54, N 7, 1712-1725 (1997).
Mitnik, L.M., Hsu, M.-K. & Liu, C.-T., ERS-1 SAR observations of
dynamic features in the southern East-China Sea. La mer,
34, 215-225 (1996).
Rogers, D.P., Johnson, D.W. & Friehe, C.A., The stable internal
boundary layer over a coastal sea. Part II: Gravity waves and momentum
balance, J. Atmos. Sci., 52, 684-696 (1995).
Scherhag, R., The Berlin fog waves of Oct. 1969, Berlin Weather
Map, Supplement, 155/69, Free University of Berlin, Germany
Scorer, R.S., Theory of waves in the lee of mountains, Quarterly
Journal of the Royal Meteorology Society, 75, 41-56 (1949).
Seitter, K.L. & Muench, H.S., Observation of a cold front with rope
cloud, Mon. Weather Rev., 113, 840-848 (1985).
Smith, R.K., Travelling waves and bores in the lower atmosphere: The
"Morning Glory" and related phenomena, Earth Sci. Rev.,
25, 267-290 (1988).
Thomson, R.E., Vachon, P.W. & Borstad, G.A., Airborne synthetic
aperture radar imagery of atmospheric gravity waves,
J. Geophys. Res., 97, 14249-14257 (1992).
Vachon, P.W., Johannessen, J.J. & Browne, D.P., ERS-1 SAR images of
atmospheric gravity waves. IEEE Trans. Geosci. Remote Sensing,
33, 4, 1014-1025 (1995).
Vachon, P.W., Johannessen, O.M. & Johannessen, J.J., An ERS 1
synthetic aperture radar image of atmospheric lee
waves. J. Geophys. Res., 99, No. C11, 22483-22490
Zheng, Q., Yan, X.-H., Klemas, V., Ho, C.R., Kuo, N.-J. & Wang, Z.,
Coastal lee waves on ERS-1 SAR images. J. Geophys. Res.,
103, No. C4, 7979-7993 (1998).
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,