Articles | Volume 11, issue 21
Atmos. Chem. Phys., 11, 10765–10777, 2011

Special issue: An integrated approach to study atmospheric greenhouse and...

Atmos. Chem. Phys., 11, 10765–10777, 2011

Research article 02 Nov 2011

Research article | 02 Nov 2011

Calibration of TCCON column-averaged CO2: the first aircraft campaign over European TCCON sites

J. Messerschmidt1,**, M. C. Geibel2, T. Blumenstock3, H. Chen2,*, N. M. Deutscher1, A. Engel7, D. G. Feist2, C. Gerbig2, M. Gisi3, F. Hase3, K. Katrynski6, O. Kolle2, J. V. Lavrič2, J. Notholt1, M. Palm1, M. Ramonet5, M. Rettinger4, M. Schmidt5, R. Sussmann4, G. C. Toon9, F. Truong5, T. Warneke1, P. O. Wennberg8, D. Wunch8, and I. Xueref-Remy5 J. Messerschmidt et al.
  • 1Institute of Environmental Physics, University of Bremen, Bremen, Germany
  • 2Max Planck Institute for Biogeochemistry, Jena, Germany
  • 3IMK-ASF, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
  • 4IMK-IFU, Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany
  • 5Laboratoire des Sciences du Climat et l'Environnement (LSCE), Gif-sur-Yvette, France
  • 6AeroMeteo Service, Bialystok, Poland
  • 7Institute for Atmospheric and Environmental Sciences, University of Frankfurt, Frankfurt, Germany
  • 8California Institute of Technology, Pasadena, CA, USA
  • 9Jet Propulsion Laboratory, Pasadena, CA, USA
  • *now at: NOAA-ESRL, Boulder, CO 80305, USA
  • **now at: California Institute of Technology, Pasadena, CA, USA

Abstract. The Total Carbon Column Observing Network (TCCON) is a ground-based network of Fourier Transform Spectrometer (FTS) sites around the globe, where the column abundances of CO2, CH4, N2O, CO and O2 are measured. CO2 is constrained with a precision better than 0.25% (1-σ). To achieve a similarly high accuracy, calibration to World Meteorological Organization (WMO) standards is required. This paper introduces the first aircraft calibration campaign of five European TCCON sites and a mobile FTS instrument. A series of WMO standards in-situ profiles were obtained over European TCCON sites via aircraft and compared with retrievals of CO2 column amounts from the TCCON instruments. The results of the campaign show that the FTS measurements are consistently biased 1.1% ± 0.2% low with respect to WMO standards, in agreement with previous TCCON calibration campaigns. The standard a priori profile for the TCCON FTS retrievals is shown to not add a bias. The same calibration factor is generated using aircraft profiles as a priori and with the TCCON standard a priori. With a calibration to WMO standards, the highly precise TCCON CO2 measurements of total column concentrations provide a suitable database for the calibration and validation of nadir-viewing satellites.

Final-revised paper