Sodium lidar studies of the horizontal variability of gravity waves in the mesosphere

• Main Author: Kwon, Kang Hyon
• Other Authors: Gardner, Chester S.
• Format: Text
• Language: English
• Published: 1989
• Subjects: Engineering; Electronics and Electrical; Norway; Pacific; Svalbard
• Online Access: http://hdl.handle.net/2142/22844

A data analysis technique for determining gravity wave intrinsic parameters is presented. The intrinsic parameters include the horizontal and vertical wavelengths, period, and wave propagation direction. The technique involves measuring the altitude variations of the wave induced density perturbations in the mesosopheric Na layer. The intrinsic horizontal wavelength of a wave observed with an airborne lidar in November 1986 was estimated to be about 85 km, and the vertical wavelength was 4.1 km. The intrinsic period was about 1.7 hours, and the propagation direction was almost due south. Kinetic energy horizontal and vertical wavenumber spectra of horizontal winds are inferred from Na density profiles collected with the airborne lidar during two flights in November 1986. The two flights include one roundtrip from Denver, Colorado to Springfield, Illinois and another roundtrip from Denver to the Pacific Coast. The horizontal wavenumber spectra exhibited an approximately k$\sb{\rm x}\sp{-1.2}$ dependence at horizontal scales from 70 to 700 km, while the vertical wavenumber spectra exhibited an approximately k$\sb{\rm z}\sp{-2.7}$ dependence at vertical scales from 2 to 10 km. In November 1986, joint lidar/radar observations were conducted. The lidar observations include the airborne observations and ground-based observations at Broomfield and Denver, Colorado. The radar observations were obtained at Platteville, Colorado with an ST radar. These joint observations revealed that waves with periods of approximately 6 hours and 2 hours were dominant at the altitudes that correspond to the bottomside of the Na layer. The characteristics of sporadic Na layers observed at Mauna Kea Observatory, Hawaii (20$\sp\circ$N, 155$\sp\circ$W) and at Nordlysstasjonen, Svalbard, Norway (78$\sp\circ$N, 16$\sp\circ$E) are also described. The mechanisms responsible for creating the sporadic Na layers observed at Mauna Kea Observatory appear to be related to diurnal tides and sporadic E layers. Made available in DSpace on ...