Progress on a Fabry-Perot Instrument for Column Measurements of CO2, O2, H2O, and CH4

We report progress on the development of a Fabry-Perot (FP) interferometer instrument that has been developed to measure the total column absorption of a number of significant atmospheric species that are important in understanding many open areas in the field of climate change and global air quality. We have demonstrated high precision measurements of total column CO2, O2, and H2O vapor using the absorption of incident sunlight and present progress on a new channel for measuring column CH4. The principle features of the FP are robustness enabling deployment in harsh field environments, low cost (less than 1/5 that of Michelson based FTIRs) and fast response reducing susceptibility to solar motion or atmospheric fluctuations that can affect the FTIR during its approximately 2 minute scan. Issues still facing the Fabry-Perot before it is ready for widespread deployment are long term stability and precise calibration. It may be necessary to include a long path absorption cell along with a deployed instrument in order to maintain stable long term calibration for the instrument. The characteristics of the instrument calibration and calibration changes with respect to time must be determined before wide spread field deployment is practical.