HR: 1340h
AN: B23A-0922    [Abstracts]
TI: Ultra-Precise Ground-based Column CO2 Measurements Using a Fabry-Perot Interferometer
AU: * Wilson, E L
EM: ewilson@pop500.gsfc.nasa.gov
AF: National Research Council, NASA/GSFC Laser & Electro-Optics Branch, Code 554, Bldg. 19, Greenbelt, MD 20771 United States
AU: Georgieva, E
EM: egeorgie@pop500.gsfc.nasa.gov
AF: Science Systems and Applications, Inc., NASA/GSFC Laser & Electro-Optics Branch, Code 554, Bldg. 19, Greenbelt, MD 20771 United States
AU: Miodek, M
EM: mmiodek@pop500.gsfc.nasa.gov
AF: Science Systems and Applications, Inc., NASA/GSFC Laser & Electro-Optics Branch, Code 554, Bldg. 19, Greenbelt, MD 20771 United States
AU: Kawa, S R
EM: srkawa@hotmail.com
AF: NASA Goddard Space Flight Center, NASA/GSFC Laser & Electro-Optics Branch, Code 554, Bldg. 19, Greenbelt, MD 20771 United States
AU: Heaps, W S
EM: wheaps@pop500.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, NASA/GSFC Laser & Electro-Optics Branch, Code 554, Bldg. 19, Greenbelt, MD 20771 United States
AB: High precision measurements of CO2 on a worldwide scale are needed to reduce uncertainties in the global carbon budget. It has been calculated that total column measurements with a precision better than 0.3% are required for this purpose. No measurement from space has ever achieved this level of precision. We present an application of a Fabry-Perot interferometer that detects spectral absorption of sunlight by atmospheric CO2 at 1571 nm. This instrument could be used to provide ground truth information for the OCO instrument, once it is implemented. A space borne version of this instrument could potentially provide more comprehensive long-term validation. Simultaneous measurements of O2 at 762 nm provide surface pressure to permit corrections for atmospheric pressure (or terrain from an airborne or space borne instrument). For measurements of each species in this differential absorption technique, transmittance fringes from a Fabry-Perot interferometer are aligned with absorption lines to maximize sensitivity to changes in absorption. These Fabry-Perot channels are subsequently compared with reference channels monitoring changes in solar flux in the wavelength region of interest. Ground based measurements presented here meet the target precision of \<0.3% with a current detection limit of better than 1 ppm in less than ten seconds averaging.
DE: 1694 Instruments and techniques
DE: 1610 Atmosphere (0315, 0325)
DE: 1640 Remote sensing
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting