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Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 35, 107-116, 2017
http://www.ann-geophys.net/35/107/2017/
doi:10.5194/angeo-35-107-2017
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Regular paper
13 Jan 2017
Vertical wavenumber spectra of three-dimensional winds revealed by radiosonde observations at midlatitude
Shao Dong Zhang1,2,3, Chun Ming Huang1,2, Kai Ming Huang1,2, Ye Hui Zhang4, Yun Gong1,2, and Quan Gan1,2 1School of Electronic Information, Wuhan University, Wuhan, Hubei, People's Republic of China
2Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan, Hubei, People's Republic of China
3State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, People's Republic of China
4College of Hydrometeorology, Nanjing University of Information Science and Technology, Nanjing, People's Republic of China
Abstract. By applying 12-year (1998–2009) radiosonde data over a midlatitude station, we studied the vertical wavenumber spectra of three-dimensional wind fluctuations. The horizontal wind spectra in the lower stratosphere coincide well with the well-known universal spectra, with mean spectral slopes of −2.91 ± 0.09 and −2.99 ± 0.09 for the zonal and meridional wind spectra, respectively, while the mean slopes in the troposphere are −2.64 ± 0.07 and −2.70  ±  0.06, respectively, which are systematically less negative than the canonical slope of −3. In both the troposphere and lower stratosphere, the spectral amplitudes (slopes) of the horizontal wind spectra are larger (less negative) in winter, and they are larger (less negative) in the troposphere than in the lower stratosphere. Moreover, we present the first statistical results of vertical wind fluctuation spectra, which revealed a very shallow spectral structure, with mean slopes of −0.58 ± 0.06 and −0.23 ± 0.05 in the troposphere and lower stratosphere, respectively. Such a shallow vertical wind fluctuation spectrum is considerably robust. Different from the horizontal wind spectrum, the slopes of the vertical wind spectra in both the troposphere and lower stratosphere are less negative in summer. The height variation of vertical wind spectrum amplitude is also different from that of the horizontal wind spectrum, with a larger amplitude in the lower stratosphere. These evident differences between the horizontal and vertical wind spectra strongly suggest they should obey different spectral laws. Quantitative comparisons with various theoretical models show that no existing spectral theories can comprehensively explain the observed three-dimensional wind spectra, indicating that the spectral features of atmospheric fluctuations are far from fully understood.

Citation: Zhang, S. D., Huang, C. M., Huang, K. M., Zhang, Y. H., Gong, Y., and Gan, Q.: Vertical wavenumber spectra of three-dimensional winds revealed by radiosonde observations at midlatitude, Ann. Geophys., 35, 107-116, doi:10.5194/angeo-35-107-2017, 2017.
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We present the first statistical results of vertical wind fluctuation spectra, which revealed a very shallow spectral structure, with mean slopes of −0.58 and −0.23 in the troposphere and lower stratosphere, respectively. No existing spectral theories can comprehensively explain the observed three-dimensional wind spectra, indicating that the spectral features of atmospheric fluctuations are far from fully understood.
We present the first statistical results of vertical wind fluctuation spectra, which revealed a...
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