Development of a Fabry-Perot Etalon spectrometer for high-resolution aerosol observations in the oxygen A-band

Aerosols are an important factor of the Earth climatic system and they play a key role for air quality and public health. Observations of the Oxygen A-Band at 760 nm can provide information on the vertical distribution of aerosols from passive sensors, that can be of great interest for operational monitoring applications with high spatial coverage if the aerosol information is obtained with sufficient precision, accuracy and vertical resolution. To address this issue, retrieval simulations of the aerosol vertical profile retrieval from Oxygen A-Band observations by GOSAT, the upcoming OCO-2 and Sentinel 5-P mission and the proposed CarbonSat mission have been carried out. These simulations suggest that such observations will be useful in the measurement of uplifted aerosols such as volcanic plumes and forest fires. Retrievals from GOSAT were also undertaken that showed promising results in challenging conditions, warranting further study. The Fabry-Perot Etalon spectrometer provides a compact, robust and affordable alternative to grating or Fourier transform spectrometers. Such an instrument was designed and optimised for the measurement of aerosol in the Oxygen A-Band and its performance simulated in comparison to GOSAT, where it competed well despite its low cost. Initial calibrations of the instrument were undertaken and showed promising results in the instrument operation concept. Following on from this simulations were used to study the performance of groundbased observations showing that using and combining a range of viewing angles would contribute significantly to the vertical information content whereas polarisation proved not to be useful except possibly in extreme circumstances.