Articles | Volume 11, issue 5
Atmos. Meas. Tech., 11, 3111–3130, 2018
Atmos. Meas. Tech., 11, 3111–3130, 2018

Research article 30 May 2018

Research article | 30 May 2018

Carbon dioxide retrieval from OCO-2 satellite observations using the RemoTeC algorithm and validation with TCCON measurements

Lianghai Wu1, Otto Hasekamp1, Haili Hu1, Jochen Landgraf1, Andre Butz2,3, Joost aan de Brugh1, Ilse Aben1, Dave F. Pollard4, David W. T. Griffith5, Dietrich G. Feist6, Dmitry Koshelev7, Frank Hase8, Geoffrey C. Toon9, Hirofumi Ohyama10, Isamu Morino10, Justus Notholt11, Kei Shiomi12, Laura Iraci13, Matthias Schneider15, Martine de Mazière14, Ralf Sussmann15, Rigel Kivi16, Thorsten Warneke11, Tae-Young Goo17, and Yao Té7 Lianghai Wu et al.
  • 1SRON Netherlands Institute for Space Research, Utrecht, the Netherlands
  • 2Institute of Atmospheric Physics, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Wessling-Oberpfaffenhofen, Germany
  • 3Meteorologisches Institut, Ludwig-Maximilians-Universität (LMU), Munich, Germany
  • 4National Institute of Water and Atmospheric Research (NIWA), Lauder, New Zealand
  • 5University of Wollongong, Wollongong, Australia
  • 6Max Planck Institute for Biogeochemistry, Jena, Germany
  • 7LERMA-IPSL, Sorbonne Universités, UPMC Univ Paris 06, CNRS, Observatoire de Paris, PSL Research University, 75005, Paris, France
  • 8Karlsruhe Institute of Technology (KIT), IMK-ASF, Karlsruhe, Germany
  • 9Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA
  • 10National Institute for Environmental Studies (NIES), Tsukuba, Japan
  • 11University of Bremen, Bremen, Germany
  • 12Japan Aerospace Exploration Agency, Tsukuba, Japan
  • 13NASA Ames Research Center, Moffett Field, USA
  • 14Royal Belgian Institute for Space Aeronomy, Brussels, Belgium
  • 15Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK-IFU), Garmisch Partenkirchen, Germany
  • 16Finnish Meteorological Institute, Sodankylä, Finland
  • 17National Institute of Meteorological Research, Seoul, Republic of Korea

Abstract. In this study we present the retrieval of the column-averaged dry air mole fraction of carbon dioxide (XCO2) from the Orbiting Carbon Observatory-2 (OCO-2) satellite observations using the RemoTeC algorithm, previously successfully applied to retrieval of greenhouse gas concentration from the Greenhouse Gases Observing Satellite (GOSAT). The XCO2 product has been validated with collocated ground-based measurements from the Total Carbon Column Observing Network (TCCON) for almost 2 years of OCO-2 data from September 2014 to July 2016. We found that fitting an additive radiometric offset in all three spectral bands of OCO-2 significantly improved the retrieval. Based on a small correlation of the XCO2 error over land with goodness of fit, we applied an a posteriori bias correction to our OCO-2 retrievals. In overpass averaged results, XCO2 retrievals have an SD of  ∼ 1.30 ppm and a station-to-station variability of  ∼ 0.40 ppm among collocated TCCON sites. The seasonal relative accuracy (SRA) has a value of 0.52 ppm. The validation shows relatively larger difference with TCCON over high-latitude areas and some specific regions like Japan.