Simulation of Lidar Measurements of Gravity Waves in the Mesosphere
D. E. Gibson-Wilde, I. M. Reid, S. D. Eckermann and R. A. Vincent
Abstract
Lidar measurements of mesospheric gravity wave characteristics
are simulated using a simple numerical model. Simple theory
is used to superimpose gravity wave fluctuations upon typical
background densities and sodium abundances in the height range
80-100 km, which we then assume are perfectly observed by a
Rayleigh and Na lidar, respectively. These lidar ``data''
are then analyzed for their gravity wave content using the standard
reduction and analysis methods which are routinely applied to
these data sets. Our goal is to assess whether this
analysis of lidar data faithfully recovers the underlying
wave field. In both quasi-monochromatic and spectral wave studies, the height range over
which Na number density can be measured and the shape of the background
Na profile impose a limit on the gravity wave information which can be extracted from
Na lidar data. The limitations due to background layer shape do not exist for
Rayleigh lidar measurements. The simulations reveal that
quasi-monochromatic gravity waves with vertical
wavelengths larger than approximately
10 km may not be reliably retrieved from Na lidar data.
It is also shown that there are limitations on the accurate extraction of
spectral parameters from Na lidar data
due to the limited vertical extent of the mesospheric Na layer.
Status
This paper has appeared in Journal of Geophysical Research -
Atmospheres, Vol. 101, D5, pp. 9509-9522, 1996.
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