Development Of Resonance Fluorescence Lidar For Studies Of The Aurora

Abstract

In this thesis I present resonance fluorescence lidar studies of the middle and upper atmosphere. I focus on two specific applications; lidar measurements of heat fluxes in the mesosphere, and lidar measurements of auroral nitrogen ions in the thermosphere. In the heat flux study, I determine the limitations in state-of-the-art sodium Doppler wind-temperature lidar measurements. I conduct statistical analysis of current lidar measurements using analytical and Monte Carlo techniques and extend them to consider future measurements. I find that the expected biases for summertime flux measurements in polar regions will be larger than the geophysical values of the fluxes. In the nitrogen resonance lidar study, I conduct a simulation of the measurements under realistic auroral conditions and found that current lidar systems should be able to make statistically significant measurements of the nitrogen profile at a resolution of 6 km and 300 s. I develop a prototype nitrogen resonance lidar system operating at 390 nm. This lidar system is based on an existing dye laser-based iron resonance lidar system that operates at 372 nm. I designed and implemented a tuning control system that allows 1 pm resolution in the laser tuning. I made a set of field measurements and found that the performance of the prototype lidar was less than expected. I conduct an engineering analysis of the measurements and conclude that the lower than expected performance is due to the lasing characteristics of the dye laser.