TCCON and NDACC XCO measurements: difference, discussion and application

• Published in: Atmospheric Measurement Techniques
• Main Authors: Zhou, Minqiang, Langerock, Bavo, Vigouroux, Corinne, Sha, Mahesh Kumar, Hermans, Christian, Metzger, Jean-Marc, Chen, Huilin, Ramonet, Michel, Kivi, Rigel, Heikkinen, Pauli, Smale, Dan, W, Pollard, David, Jones, Nicholas, Velazco, Voltaire, Garcìa, Omaira, Schneider, Matthias, Palm, Mathias, Warneke, Thorsten, de Mazière, Martine
• Other Authors: Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Centre de Recherche Saint-Antoine (UMRS893), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire de Physiologie et de Génétique Moléculaire des Plantes, Université libre de Bruxelles (ULB), Observatoire des Sciences de l'Univers de La Réunion (OSU-Réunion), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Météo-France, Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ICOS-RAMCES (ICOS-RAMCES), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Finnish Meteorological Institute (FMI), National Institute of Water and Atmospheric Research Lauder (NIWA), Centre for Atmospheric Chemistry Wollongong (CAC), University of Wollongong Australia, Izaña Atmospheric Research Center (IARC), Agencia Estatal de Meteorología (AEMet), Institute for Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Department of Physics Bremen, University of Bremen, Institut für Umweltphysik Bremen (IUP), Universität Bremen
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDU]Sciences of the Universe [physics]; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Ny-Ålesund; Sodankylä; Ny Ålesund
• Online Access: https://hal.science/hal-02414324; https://hal.science/hal-02414324/document; https://hal.science/hal-02414324/file/amt-12-5979-2019.pdf; https://doi.org/10.5194/amt-12-5979-2019

International audience Column-averaged dry-air mole fraction of CO (X CO) measurements are obtained from two ground-based Fourier transform infrared (FTIR) spectrometer networks: the Total Carbon Column Observing Network (TCCON) and the Network for the Detection of Atmospheric Composition Change (NDACC). In this study, the differences between the TCCON and NDACC X CO measurements are investigated and discussed based on six NDACC-TCCON sites using data over the period 2007-2017. A direct comparison shows that the NDACC X CO measurements are about 5.5 % larger than the TCCON data at Ny-Ålesund, Bremen, and Izaña (North-ern Hemisphere), and the absolute bias between the NDACC and TCCON data is within 2 % at Saint-Denis, Wollongong and Lauder (Southern Hemisphere). The hemispheric dependence of the bias is mainly attributed to their smoothing errors. The systematic smoothing error of the TCCON X CO data varies in the range between 0.2 % (Bremen) and 7.9 % (Lauder), and the random smoothing error varies in the range between 2.0 % and 3.6 %. The systematic smoothing error of NDACC data is between 0.1 % and 0.8 %, and the random smoothing error of NDACC data is about 0.3 %. For TCCON data, the smoothing error is significant because it is higher than the reported uncertainty, particularly at Southern Hemisphere sites. To reduce the influence from the a priori profiles and different vertical sensitivities, the scaled NDACC a priori profiles are used as the common a priori profiles for comparing TCCON and NDACC retrievals. As a result, the biases between TCCON and NDACC X CO measurements become more consistent (5.6 %-8.5 %) with a mean value of 6.8 % at these sites. To determine the sources of the remaining bias, regular AirCore measurements at Orléans and Sodankylä are compared to co-located TCCON measurements. It is found that TCCON X CO measurements are 6.1 ± 1.6 % and 8.0 ± 3.2 % smaller than the AirCore measurements at Orléans and Sodankylä, respectively, indicating that the scaling factor of TCCON X CO data should ...