Application of Tomographic Inversion in Studying Airglow in the Mesopause Region

Authors

T. Nygren
Michael J. Taylor, Utah State UniversityFollow
M. S. Lehtinen
M. Markkanen

Document Type

Article

Journal/Book Title/Conference

Annales Geophysicae

Volume

16

Issue

10

Publisher

European Geosciences Union

Publication Date

4-1998

First Page

1180

Last Page

1189

Abstract

It is pointed out that observations of periodic nightglow structures give excellent information on atmospheric gravity waves in the mesosphere and lower thermosphere. The periods, the horizontal wavelengths and the phase speeds of the waves can be determined from airglow images and, using several cameras, the approximate altitude of the luminous layer can also be determined by triangulation. In this paper the possibility of applying tomographic methods for reconstructing the airglow structures is investigated using numerical simulations. A ground-based chain of cameras is assumed, two-dimensional airglow models in the vertical plane above the chain are constructed, and simulated data are calculated by integrating the models along a great number of rays with different elevation angles for each camera. After addition of random noise, these data are then inverted to obtain reconstructions of the models. A tomographic analysis package originally designed for satellite radiotomography is used in the inversion. The package is based on a formulation of stochastic inversion which allows the input of a priori information to the solver in terms of regularization variances. The reconstruction is carried out in two stages. In the first inversion, constant regularization variances are used within a wide altitude range. The results are used in determining the approximate altitude range of the airglow structures. Then, in the second inversion, constant non-zero regularization variances are used inside this region and zero variances outside it. With this method reliable reconstructions of the models are obtained. The number of cameras as well as their separations are varied in order to find out the limitations of the method.

Comments

Published by European Geosciences Union in Annales Geophysicae.

http://www.ann-geophys.net/16/1180/1998/angeo-16-1180-1998.html

Publisher PDF is available for download through the link above.

Recommended Citation

Nygren, T., M.J. Taylor, M.S. Lehtinen, and M. Markkanen, Application of tomographic inversion in studying airglow in the mesopause region, Ann. Geophysicae,16, 1180, 1998.