Lidar studies of sporadic sodium layers, gravity waves and density spectra in the mesopause and stratopause regions at Urbana and Arecibo.

摘要

The high spatial and temporal resolution of the UIUC CEDAR lidar and new processing techniques have significantly improved the study of vertical and temporal structures of the middle atmosphere. This thesis paper first presents what are believed to be the first observations of meteor ablation trails with a lidar. Next, the simultaneous observations of a sporadic E layer by the Arecibo 430 MHz incoherent scatter radar and a sporadic Na layer by the UIUC CEDAR Na lidar are presented. The high correlation between the altitude and abundance variation of the two layers is discussed.; Finally, the results of thirty nights of lidar observations during the months of January, March and April 1989 at the Arecibo Observatory are presented. The CEDAR lidar was operated as a Rayleigh and Na lidar and was one of several optical and radar instruments participating in the AIDA Act '89 campaign. The characteristics of the monochromatic gravity waves, gravity wave spectra and rms density perturbations observed simultaneously in the stratopause (25-55 km) and mesopause (80-105 km) regions above Arecibo are described. Similarities in and differences between the wave characteristics in the two regions are discussed, and the results are compared with previous radar and lidar observations obtained at other sites.