Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published June 2017 | Published
Journal Article Open

Comparisons of the Orbiting Carbon Observatory-2 (OCO-2) X_(CO_2) measurements with TCCON

Abstract

NASA's Orbiting Carbon Observatory-2 (OCO-2) has been measuring carbon dioxide column-averaged dry-air mole fraction, X_(CO_2), in the Earth's atmosphere for over 2 years. In this paper, we describe the comparisons between the first major release of the OCO-2 retrieval algorithm (B7r) and X_(CO2) from OCO-2's primary ground-based validation network: the Total Carbon Column Observing Network (TCCON). The OCO-2 X_(CO_2) retrievals, after filtering and bias correction, agree well when aggregated around and coincident with TCCON data in nadir, glint, and target observation modes, with absolute median differences less than 0.4 ppm and RMS differences less than 1.5 ppm. After bias correction, residual biases remain. These biases appear to depend on latitude, surface properties, and scattering by aerosols. It is thus crucial to continue measurement comparisons with TCCON to monitor and evaluate the OCO-2 X_(CO_2) data quality throughout its mission.

Additional Information

© 2017 Author(s). This work is distributed under the Creative Commons Attribution 3.0 License. Received: 06 Jul 2016 – Discussion started: 29 Aug 2016. Revised: 12 Apr 2017 – Accepted: 30 Apr 2017 – Published: 13 Jun 2017. Part of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. The operation of the Ascension Island site was funded by the Max Planck Society. The Bremen, Białystok, and Orléans TCCON sites are funded by the EU projects InGOS and ICOS-INWIRE as well as by the Senate of Bremen. The Darwin and Wollongong TCCON sites are funded by NASA grants NAG512247 and NNG05GD07G and by Australian Research Council grants DP140101552, DP110103118, DP0879468, LE0668470, and LP0562346. We are grateful to the DOE ARM program for technical support at the Darwin TCCON site. Nicholas M. Deutscher was supported by an Australian Research Council fellowship, DE140100178. The TCCON site at Réunion Island is operated by the Royal Belgian Institute for Space Aeronomy with financial support in 2014, 2015, and 2016 under the EU project ICOS-Inwire and the ministerial decree for ICOS (FR/35/IC2) and local activities supported by LACy/UMR8105 – Université de La Réunion. TCCON is funded by NASA grants NNX14AI60G, NNX11AG01G, NAG5-12247, NNG05-GD07G, and NASA's Orbiting Carbon Observatory Program. We are grateful to the DOE ARM program for technical support in Lamont and Jeff Ayers for technical support in Park Falls. From 2004 to 2011 the Lauder TCCON program was funded by the New Zealand Foundation of Research Science and Technology contracts CO1X0204, CO1X0703, and CO1X0406. Since 2011 the program has been funded by NIWA's Atmosphere Research Programme 3 (2011/13 Statement of Corporate Intent). The TCCON measurements at Eureka are made by the Canadian Network for the Detection of Atmospheric Change (CANDAC), led by James R. Drummond, and in part by the Canadian Arctic ACE Validation Campaigns, led by Kaley A. Walker. They are supported by the Atlantic Innovation Fund/Nova Scotia Research Innovation Trust, Canada Foundation for Innovation, Canadian Foundation for Climate and Atmospheric Sciences, Canadian Space Agency, Environment Canada, Government of Canada International Polar Year funding, Natural Sciences and Engineering Research Council, Northern Scientific Training Program, Ontario Innovation Trust, and Ontario Research Fund and Polar Continental Shelf Program. We thank PEARL site manager Pierre Fogal, the staff at the Eureka weather station, and the CANDAC operators for the logistical and on-site support provided at Eureka. Manvendra K. Dubey thanks DOE OBER's TES and NGEE-Tropics program for funding and ARM for logistical support of the TCCON deployment during the GoAmazon campaign. Author contributions. Debra Wunch wrote the manuscript and produced the main analysis and results with significant input from Gregory Osterman, Camille Viatte, and Paul O. Wennberg. Debra Wunch, Gregory Osterman, Brendan Fisher, Matthäus Kiel, Bret Naylor, Coleen M. Roehl, Christopher O'Dell, Annmarie Eldering, Lukas Mandrake, Camille Viatte, Michael R. Gunson, David Crisp, and Paul O. Wennberg contributed to the experiment design and analysis of data. David W. T. Griffith, Nicholas M. Deutscher, Voltaire A. Velazco, Justus Notholt, Thorsten Warneke, Christof Petri, Martine De Maziere, Mahesh K. Sha, Ralf Sussmann, Markus Rettinger, David Pollard, John Robinson, Isamu Morino, Osamu Uchino, Frank Hase, Thomas Blumenstock, Matthäus Kiel, Dietrich G. Feist, Sabrina G. Arnold, Kimberly Strong, Joseph Mendonca, Rigel Kivi, Pauli Heikkinen, Laura Iraci, James Podolske, Patrick W. Hillyard, Shuji Kawakami, Manvendra K. Dubey, Harrison A. Parker, Eliezer Sepulveda, Omaira E. García, Yao Te, and Pascal Jeseck provided TCCON data. All authors read and provided comments on the manuscript. The authors declare that they have no conflict of interest.

Attached Files

Published - amt-10-2209-2017.pdf

Files

amt-10-2209-2017.pdf
Files (7.5 MB)
Name Size Download all
md5:46a432b99d6d93bc2e1a7cfbe1a12a75
7.5 MB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 18, 2023