M Buchwitz, University of Bremen
Markus Reuter, University of Bremen
O Schneising, University of Bremen
Hartmut Boesch, University of Leicester
Sandrine Guerlet, SRON Netherlands Institute for Space Research
B Dils, Belgian Institute for Space Aeronomy
Ilse Aben, Netherlands Institute for Space Research
R Armante, Karlsruhe Institute of Technology
P Bergamaschi, European Commission Joint Research Centre, Italy
Thomas Blumenstock, Karlsruhe Institute of Technology
H Bovensmann, Universitat Bremen
D Brunner, Swiss Federal Laboratories for Materials Science and Technology
B Buchmann, Swiss Federal Laboratories for Materials Science and Technology
J P. Burrows, University of Bremen
Andre Butz, Karlsruhe Institute of Technology
A Chedin, Laboratoire de Meteorologie Dynamique
Frédéric Chevallier, CNRS Centre National de la Recherche ScientifiqueFollow
C D. Crevoisier, Laboratoire de Meteorologie Dynamique
Nicholas M. Deutscher, University of WollongongFollow
Christian Frankenberg, California Institute of Technology
Frank Hase, Karlsruhe Institute of Technology
Otto Hasekamp, Netherlands Institute for Space Research
J Heymann, University of Bremen
T Kaminski, FastOpt
A Laeng, Karlsruhe Institute of Technology
G Lichtenberg, Deutsches Zentrum Fur Luft- Und Raumfahrt
M De Mazière, (IASB-BIRA), Brussels
S Noel, University of Bremen
Justus Notholt, University of Bremen
J Orphal, Karlsruhe Institute of Technology
C Popp, Swiss Federal Laboratories for Materials Science and Technology
Robert J. Parker, University of Leicester
M Scholze, University of Bristol
Ralf Sussmann, Karlsruhe Institute of Technology
G Stiller, Karlsruhe Institute of Technology
Thorsten Warneke, University of Bremen
C Zehner, European Space Agency
Andrey Bril, National Institute for Environmental Studies
David Crisp, California Institute of Technology
David W. T Griffith, University of WollongongFollow
A Kuze, Japan Aerospace Exploration Agency
Christopher O'Dell, Colorado State University
Sergey Oshchepkov, National Institute for Environmental Studies
Vanessa Sherlock, National Institute of Water and Atmospheric Research, New Zealand
H Suto, Japan Aerospace Exploration Agency
Paul O. Wennberg, California Institute of Technology
Debra Wunch, California Institute of Technology
Tatsuya Yokota, National Institute for Environmental Studies, Japan
Yukio Yoshida, National Insitute for Environmental Studies, Japan



Publication Details

Buchwitz, M., Reuter, M., Schneising, O., Boesch, H., Guerlet, S., Dils, B., Aben, I., Armante, R., Bergamaschi, p., Blumenstock, T., Bovensmann, H., Brunner, D., Buchmann, B., Burrows, J. P., Butz, A., Chedin, A., Chevallier, F., Crevoisier, C. D., Deutscher, N. M., Frankenberg, C., Hase, F., Hasekamp, O. P., Heymann, J., Kaminski, T., Laeng, A., Lichtenberg, G., De Maziere, M., Noel, S., Notholt, J., Orphal, J., Popp, C., Parker, R., Scholze, M., Sussmann, R., Stiller, G. P., Warneke, T., Zehner, C., Bril, A., Crisp, D., Griffith, D. W. T., Kuze, A., O'Dell, C., Oshchepkov, S., Sherlock, V., Suto, H., Wennberg, P., Wunch, D., Yokota, T. & Yoshida, Y. (2015). The Greenhouse Gas Climate Change Initiative (GHG-CCI): comparison and quality assessment of near-surface-sensitive satellite-derived CO2 and CH4 global data sets. Remote Sensing of Environment: an interdisciplinary journal, 162 344-362.


The GHG-CCI project is one of several projects of the European Space Agency's (ESA) Climate Change Initiative (CCI). The goal of the CCI is to generate and deliver data sets of various satellite-derived Essential Climate Variables (ECVs) in line with GCOS (Global Climate Observing System) requirements. The "ECV Greenhouse Gases" (ECV GHG) is the global distribution of important climate relevant gases - atmospheric CO2 and CH4 - with a quality sufficient to obtain information on regional CO2 and CH4 sources and sinks. Two satellite instruments deliver the main input data for GHG-CCI: SCIAMACHY/ENVISAT and TANSO-FTS/GOSAT. The first order priority goal of GHG-CCI is the further development of retrieval algorithms for near-surface-sensitive column-averaged dry air mole fractions of CO2 and CH4, denoted XCO2 and XCH4, to meet the demanding user requirements. GHG-CCI focuses on four core data products: XCO2 from SCIAMACHY and TANSO and XCH4 from the same two sensors. For each of the four core data products at least two candidate retrieval algorithms have been independently further developed and the corresponding data products have been quality-assessed and inter-compared. This activity is referred to as "Round Robin" (RR) activity within the CCI. The main goal of the RR was to identify for each of the four core products which algorithms should be used to generate the Climate Research Data Package (CRDP). The CRDP will essentially be the first version of the ECV GHG. This manuscript gives an overview of the GHG-CCI RR and related activities. This comprises the establishment of the user requirements, the improvement of the candidate retrieval algorithms and comparisons with ground-based observations and models. The manuscript summarizes the final RR algorithm selection decision and its justification. Comparison with ground-based Total Carbon Column Observing Network (TCCON) data indicates that the "breakthrough" single measurement precision requirement has been met for SCIAMACHY and TANSO XCO2 (< 3 ppm) and TANSO XCH4 (< 17 ppb). The achieved relative accuracy for XCH4 is 3-15 ppb for SCIAMACHY and 2-8 ppb for TANSO depending on algorithm and time period. Meeting the 0.5 ppm systematic error requirement for XCO2 remains a challenge: approximately 1 ppm has been achieved at the validation sites but also larger differences have been found in regions remote from TCCON. More research is needed to identify the causes for the observed differences. In this context GHG-CCI suggests taking advantage of the ensemble of existing data products, for example, via the EnseMble Median Algorithm (EMMA).

Grant Number

ARC/DP0879468, ARC/LP0562346