We performed comparative studies to establish favorable spectral regions and measurement wavelength combinations in alternative bands of CO2 and O2, for the sensing of CO2 mixing ratios (XCO2) in missions such as ASCENDS. The analysis employed several simulation approaches including separate layers calculations based on pre-analyzed atmospheric data from the modern-era retrospective analysis for research and applications (MERRA), and the line-by-line radiative transfer model (LBLRTM) to obtain achievable accuracy estimates as a function of altitude and for the total path over an annual span of variations in atmospheric parameters. Separate layer error estimates also allowed investigation of the uncertainties in the weighting functions at varying altitudes and atmospheric conditions. The parameters influencing the measurement accuracy were analyzed independently and included temperature sensitivity, water vapor interferences, selection of favorable weighting functions, excitations wavelength stabilities and other factors. The results were used to identify favorable spectral regions and combinations of on / off line wavelengths leading to reductions in interferences and the improved total accuracy.

Date Published: 31 May 2013
PDF: 9 pages
Proc. SPIE 8718, Advanced Environmental, Chemical, and Biological Sensing Technologies X, 87180L (31 May 2013); doi: 10.1117/12.2016337

Published in SPIE Proceedings Vol. 8718:
Advanced Environmental, Chemical, and Biological Sensing Technologies X
Tuan Vo-Dinh; Robert A. Lieberman; Günter G. Gauglitz, Editor(s)