A length-modulated radiometer for remote sounding of carbon monoxide.

摘要

This thesis describes the development of a new correlation radiometry technique for remote sounding of the atmosphere known as length modulation. It is comprised of two main parts: the characterisation of the correlation system and its deployment in a ground-based instrument to measure CO in the lower atmosphere.;The Length Modulated Cell (LMC) performs gas density modulation inside of a correlation cell by modulating the gas path length through the cell. The design and implementation of the LMC in a Length Modulated Radiometer (LMR) is described. The characterisation of the LMR is described, identifying the significant factors affecting its performance. Methods of improving performance are studied and some are implemented. The radiometric calibration of the LMR with CO is presented, including an analysis of the sources of error in the calibration.;The design of the ground-based instrument for measuring atmospheric CO is described. An analysis of the theoretical performance of the instrument is presented. This analysis includes the instrument sensitivity of CO, the signal function of the instrument, and the effects of other interfering atmospheric species. The initial results of a series of atmospheric CO measurements made in Toronto and north of Toronto are presented.