Spatial Heterodyne Observations of Water (SHOW) Instrument Characterization

Water vapour plays a dominant role in the dynamics and thermal balance of the middle atmosphere. The Spatial Heterodyne Observation of Water (SHOW) instrument is a Spatial Heterodyne Spectrometer (SHS) built to provide high-resolution measurements of water in the middle atmosphere up to ∼ 85 km (the mesosphere). For the purpose, a monolithic SHS, with a Littrow wavelength of 1363.07 nm, was designed and built at the CRESS Space Instrumentation Laboratory. .;The SHOW instrument was tested within the water cell while altering the different user-defined parameters of the simulated H2O environment (H2O pressure, lamp current, and temperature). The variation of H2O pressure provided water absorption measurements for varying column densities of water within the one-meter water cell. The variation of the water cell temperature alters the column density to test SHOW's ability to measure H2O absorption over small alterations. In each case, the SHOW instrument effectively measures H2O absorption at the targeted spectral lines.;The focus of this thesis is the characterization and calibration of the SHOW instrument by performing wavelength registration, radiometric calibration, and instrument calibration. The wavelength registration was completed by using a calibrated krypton and argon source and imaging it with SHOW, while the radiometric calibration was completed using an approach based on Englert and Harlander's flat-fielding technique. SHOW viewed a calibrated lamp source with a 300 nm - 2400 nm calibration range reflecting from a Barium Sulfate screen. The minimum measurement conducted was at 0.1 Ton H2O pressure within the one-meter water cell, of 6.4% absorption with 1.3% absorption (20.3% error)).