Lidar studies of gravity waves in the mesopause region

Nightly and seasonal variations in gravity wave activity in the mesopause region are examined by analyzing 60 nights of Na lidar observations obtained during a five-year period at Urbana, Illinois. The lidar data were used to calculate atmospheric density perturbations and their spectra. The atmospheric density variances, density vertical shear variances, vertical wind variances, ω-spectra magnitudes, and m-spectra magnitudes all exhibit considerable nightly variability as well as strong annual and semi-annual variations with the largest values in summer. The annual mean value of the rms density perturbations is 5.6%, with a mid-summer value that is 2 to 3 times larger. The Richardson number for the wave field varies between 1/2 and 2 for most of the year, although Ri sometimes falls well below 1/4 during the summer.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Senft, Daniel Charles

Contributors dc:contributor

• Gardner, Chester S.

• Geophysics
• Engineering, Electronics and Electrical
• Physics, Atmospheric Science

Statement dc:rights

• Copyright 1991 Senft, Daniel Charles

Language dc:language

eng

Identifier

AAI9210985
(UMI)AAI9210985

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/22205