Spectral analysis of monsoonal global energy and enstrophy and their nonlinear exchanges in the zonal wavenumber domain

Desai, S. S. ; Mishra, S. K. (1994) Spectral analysis of monsoonal global energy and enstrophy and their nonlinear exchanges in the zonal wavenumber domain Proceedings of the Indian Academy of Sciences - Earth and Planetary Sciences, 103 (4). pp. 469-488. ISSN 0253-4126

PDF - Publisher Version

Official URL: http://www.ias.ac.in/j_archive/epsci/103/4/469-488...

Related URL: http://dx.doi.org/10.1007/BF02839291


Vertical distributions of various components of the tropospheric global rotational kinetic energy, enstrophy and available potential energy during July 1979, and the contributions to these from different zonal wave categories were studied. Representative levels in the lower and upper troposphere for the stationary and transient energetics were identified on the basis of different components of energy and enstrophy. The eddy energy and enstrophy contained in different zonal scale components in the lower and upper troposphere were studied to find out the preferred scales for stationary and transient monsoonal motion in the two atmospheric layers. The role of different zonal wave categories in the nonlinear exchanges of energy and enstrophy arising due to stationary-stationary, transient-transient, stationary-transient and observed flow interactions was examined. Stationary and transient global spectra of the aforesaid dynamical variables in terms of the zonal wavenumber(m) with triangular truncation at m = 42 were utilized for this purpose. It was found from the global average kinetic energy in lower and upper troposphere that the global stationary and transient motions were comparable in the lower troposphere while in the upper troposphere stationary motion dominated over the transient motion. The computed zonal and eddy energy confirmed that the stationary motion was predominantly zonal while the transient motion was dominated by eddies. From the time mean nonlinear interaction of kinetic energy (enstrophy) of observed flow it was seen that the long and short waves as well as the zonal flow gained kinetic energy (enstrophy) from medium waves due to nonlinear interactions. The transfer of available potential energy due to nonlinear interaction was down the scale except for short waves in the upper troposphere. The stationary-transient interaction was found to be an important element of the spatial-temporal varying atmospheric flow.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Global Energy and Enstrophy Spectra; Nonlinear Interactions; Wave Categories; Representative Levels
ID Code:20128
Deposited On:20 Nov 2010 14:58
Last Modified:17 May 2016 04:31

Repository Staff Only: item control page