Abstract
The region of the optical spectrum known as the Ultraviolet (UV) has long been a waveband of interest for atmospheric studies. Space-based observations of the backscattered radiation in this region can provide a significant amount of information regarding the atmospheric dynamics and composition. Important atmospheric constituents such as: Ozone, Sulphur Dioxide and Aerosols are normally studied using instrumentation observing specific wavelengths in the UV. In this region, the radiance levels are at least two orders of magnitude lower than in the visible range. Therefore, the instrumentation requirements are severe and the remote sensing efforts have traditionally relied almost exclusively on a few large-scale satellite platforms that provide a limited number of observations. This thesis contributes to the state-of-the-art in instrument design by developing a novel miniaturised UV imaging spectrometer. This low-cost instrument concept is suitable for a constellation of low-cost micro-satellites and with an adequate performance to provide additional atmospheric observations of scientific value. Applications such as: climate studies on ozone depletion, aerosol dynamics and volcanic monitoring of emissions normally containing sulphur dioxide can greatly benefit if additional daily observations from this instrument are provided. Furthermore, an efficient monitoring of hazardous volcanic clouds for aviation activities could be implemented taking advantage of the rapid response and current operational capabilities of micro-satellites. A suitable instrument is proposed for the above mentioned applications with ground sample distance of 7 x 30 km and daily revisits are possible if used in a constellation. The use of key components such as visible-blind Silicon Carbide (SiC) detectors and high-efficiency transmission gratings is proposed to allow the sensitivity required for the applications. A comprehensive model was developed to account for atmospheric conditions and instrument specifications for an appropriate set of wavelengths (305-315 nm, 331 nm and 360 nm ~1 nm resolution). A prototype was built to confirm the sensitivity and low-noise performance; the results obtained indicate its suitability for use in retrieval algorithms which are also given. The instrument concept developed can enable micro-satellites with UV capabilities for new atmospheric missions.