Our group has developed a 20 μm passive atmospheric water vapour monitor. The Infrared Radiometer for Millimetre Astronomy (IRMA) has been commissioned and deployed for site testing for the Thirty Meter Telescope (TMT) and the Giant Magellan Telescope (GMT). Measuring precipitable water vapour (PWV) requires both a sophisticated atmospheric model (BTRAM) and an instrument (IRMA). Atmospheric models depend on atmospheric profiles. Most profiles are generic in nature, representing only a latitude in some cases. Site-specific atmospheric profiles are required to accurately simulate the atmosphere above any location on Earth. These profiles can be created from publicly available archives of radiosonde data, that offer nearly global coverage. Having created a site-specific profile and model, it is necessary to determine the PWV sensitivity to the input parameter uncertainties used in the model. The instrument must also be properly calibrated. In this thesis, I describe the radiometric calibration of the IRMA instrument, and the creation and analysis of site-specific atmospheric models for use with the IRMA instrument in its capacity as an atmospheric water vapour monitor for site testing. / xii, 135 leaves : ill. ; 28 cm. --

The Infrared Radiometer for Millimetre Astronomy (IRMA) is a passive atmospheric water vapour monitor developed at the University of Lethbridge. It is a compact, robust, and autonomous instrument, which is capable of being operated remotely. The latest model is based on a PC/104 running an AMD 133 MHz SC520 processor, which allows for more flexible control of the unit. The modifications and upgrades to the software required for the transition to this new platform are discussed in this thesis. In addition to software optimisation, a new calibration method has been developed as the unit has become better understood. This method has been verified through test campaigns carried out in Lethbridge and Chile. The results of these tests are included in this thesis. / xii, 141 leaves : ill. (some col.) ; 28 cm. --