Studies were performed to carry out semi-empirical validation of a new measurement approach we propose for molecular mixing ratios determination. The approach is based on relative measurements in bands of O₂ and other molecules and as such may be best described as cross band relative absorption (CoBRA). The current validation studies rely upon well verified and established theoretical and experimental databases, satellite data assimilations and modeling codes such as HITRAN, line-by-line radiative transfer model (LBLRTM), and the modern-era retrospective analysis for research and applications (MERRA). The approach holds promise for atmospheric mixing ratio measurements of CO₂ and a variety of other molecules currently under investigation for several future satellite lidar missions. One of the advantages of the method is a significant reduction of the temperature sensitivity uncertainties which is illustrated with application to the ASCENDS mission for the measurement of CO₂ mixing ratios (XCO₂). Additional advantages of the method include the possibility to closely match cross-band weighting function combinations which is harder to achieve using conventional differential absorption techniques and the potential for additional corrections for water vapor and other interferences without using the data from numerical weather prediction (NWP) models.

Date Published: 20 May 2013
PDF: 12 pages
Proc. SPIE 8731, Laser Radar Technology and Applications XVIII, 87310L (20 May 2013); doi: 10.1117/12.2016661

Published in SPIE Proceedings Vol. 8731:
Laser Radar Technology and Applications XVIII
Monte D. Turner; Gary W. Kamerman, Editor(s)