Intercomparability of XCO2 and XCH4 from the United States TCCON sites
Jacob K. Hedelius1, Harrison Parker2, Debra Wunch3,a, Coleen M. Roehl3, Camille Viatte3, Sally Newman3, Geoffrey C. Toon4,3, James R. Podolske5, Patrick W. Hillyard5,6, Laura T. Iraci5, Manvendra K. Dubey2, and Paul O. Wennberg3,71Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA 2Earth and Environmental Science, Los Alamos National Laboratory, Los Alamos, NM, USA 3Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA 4Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA 5NASA Ames Research Center, Mountain View, CA, USA 6Bay Area Environmental Research Institute, Petaluma, CA 7Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA anow at: Department of Physics, University of Toronto, Toronto, Ontario, Canada
Received: 25 Aug 2016 – Accepted for review: 14 Sep 2016 – Discussion started: 15 Sep 2016
Abstract. The Total Carbon Column Observing Network (TCCON) has become the standard for long-term column-averaged measurements of CO2 and CH4. Here, we use a pair of portable spectrometers to test for intra-network bias among the four currently operating TCCON sites in the United States (U.S.). A previous analytical error analysis has suggested that the maximum 2σ site-to-site relative (absolute) bias of TCCON should be less than 0.2 % (0.8 ppm) in XCO2 and 0.4 % (7 ppb) in XCH4. We find here experimentally that the 95 % confidence intervals for maximum pairwise site-to-site bias among the four U.S. TCCON sites are 0.05–0.14 % for XCO2 and 0.08–0.24 % for XCH4. This is close to the limit of the bias we can detect using this methodology.
Hedelius, J. K., Parker, H., Wunch, D., Roehl, C. M., Viatte, C., Newman, S., Toon, G. C., Podolske, J. R., Hillyard, P. W., Iraci, L. T., Dubey, M. K., and Wennberg, P. O.: Intercomparability of XCO2 and XCH4 from the United States TCCON sites, Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-279, in review, 2016.