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Ann. Geophys., 24, 3257-3265, 2006
www.ann-geophys.net/24/3257/2006/
© European Geosciences Union 2006
Radiosonde observations of vertical wave number spectra for gravity waves in the lower atmosphere over Central China
Shao Dong Zhang1,2, Chunming Huang1,2, and Fan Yi1,2
1School of Electronic Information, Wuhan University, Wuhan, People's Republic of China
2Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan, People's Republic of China
Abstract. Vertical wave number spectra of inertial gravity waves in
the troposphere and lower stratosphere over six stations at latitudes from
20° N to 40° N were statistically studied by using the data from
Radiosonde observation on a twice daily basis at 08:00 and 20:00 LT.
Statistically, the spectral characteristics seem to be independent of the
local observation time, and show considerable conformity between the
spectral of zonal and meridional kinetic energy densities. Compared with the
spectra of the kinetic energy density, the spectra of the potential energy
density are steeper. in addition the characteristic wave numbers of the spectra also
show considerable consistency among the observations at different stations.
As for the spectral slopes, they are systematically smaller (in magnitude)
than the canon value of –3, and exhibit slight height, seasonal and
latitudinal variability. In addition to these universal characteristics, the
spectral structures also exhibit departures and variations, and most of the
departures and variations are related to the strong tropospheric jets.
Generally, in the case of strong shear due to the tropospheric jet, there
usually occur larger characteristic wave numbers and smaller spectral slopes.
These departures seem to be persistent and climatological rather than
transitory, indicating the significant impacts of the sheared background
winds on the spectral structures of gravity waves.
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