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OCO-3 early mission operations and initial (vEarly) XCO₂ and SIF retrievals

Taylor, Thomas E. and Eldering, Annmarie and Merrelli, Aronne and Kiel, Matthäus and Somkuti, Peter and Cheng, Cecilia and Rosenberg, Robert and Fisher, Brendan and Crisp, David and Basilio, Ralph and Bennett, Matthew and Cervantes, Daniel and Chang, Albert and Dang, Lan and Frankenberg, Christian and Haemmerle, Vance R. and Keller, Graziela R. and Kurosu, Thomas and Laughner, Joshua L. and Lee, Richard and Marchetti, Yuliya and Nelson, Robert R. and O'Dell, Christopher W. and Osterman, Gregory and Pavlick, Ryan and Roehl, Coleen and Schneider, Robert and Spiers, Gary and To, Cathy and Wells, Christopher and Wennberg, Paul O. and Yelamanchili, Amruta and Yu, Shanshan (2020) OCO-3 early mission operations and initial (vEarly) XCO₂ and SIF retrievals. Remote Sensing of Environment, 251 . Art. No. 112032. ISSN 0034-4257. doi:10.1016/j.rse.2020.112032.

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NASA's Orbiting Carbon Observatory-3 (OCO-3) was installed on the International Space Station (ISS) on 10 May 2019. OCO-3 combines the flight spare spectrometer from the Orbiting Carbon Observatory-2 (OCO-2) mission, which has been in operation since 2014, with a new Pointing Mirror Assembly (PMA) that facilitates observations of non-nadir targets from the nadir-oriented ISS platform. The PMA is a new feature of OCO-3, which is being used to collect data in all science modes, including nadir (ND), sun-glint (GL), target (TG), and the new snapshot area mapping (SAM) mode. This work provides an initial assessment of the OCO-3 instrument and algorithm performance, highlighting results from the first 8 months of operations spanning August 2019 through March 2020. During the In-Orbit Checkout (IOC) phase, critical systems such as power and cooling were verified, after which the OCO-3 spectrometer and PMA were subjected to a series of rigorous tests. First light of the OCO-3 spectrometer was on 26 June 2019, with full science operations beginning on 6 August 2019. The OCO-3 spectrometer on-orbit performance is consistent with that seen during preflight testing. Signal to noise ratios are in the expected range needed for high quality retrievals of the column-averaged carbon dioxide (CO₂) dry-air mole fraction (XCO₂) and solar-induced chlorophyll fluorescence (SIF), which will be used to help quantify and constrain the global carbon cycle. The first public release of OCO-3 Level 2 (L2) data products, called “vEarly”, is being distributed by NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC). The intent of the vEarly product is to evaluate early mission performance, facilitate comparisons with OCO-2 products, and identify key areas to improve for the next data release. The vEarly XCO2 exhibits a root-mean-squared-error (RMSE) of ≃ 1, 1, 2 ppm versus a truth proxy for nadir-land, TG&SAM, and glint-water observations, respectively. The vEarly SIF shows a correlation with OCO-2 measurements of >0.9 for highly coincident soundings. Overall, the Level 2 SIF and XCO₂ products look very promising, with performance comparable to OCO-2. A follow-on version of the OCO-3 L2 product containing a number of refinements, e.g., instrument calibration, pointing accuracy, and retrieval algorithm tuning, is anticipated by early in 2021.

Item Type:Article
Related URLs:
URLURL TypeDescription
Taylor, Thomas E.0000-0002-1650-4882
Eldering, Annmarie0000-0003-1080-9922
Kiel, Matthäus0000-0002-9784-962X
Somkuti, Peter0000-0002-5858-8471
Rosenberg, Robert0000-0002-0459-4630
Crisp, David0000-0002-4573-9998
Frankenberg, Christian0000-0002-0546-5857
Laughner, Joshua L.0000-0002-8599-4555
Lee, Richard0000-0001-6509-697X
Nelson, Robert R.0000-0002-3471-5683
Roehl, Coleen0000-0001-5383-8462
Wennberg, Paul O.0000-0002-6126-3854
Alternate Title:OCO-3 early mission operations and initial (vEarly) XCO2 and SIF retrievals
Additional Information:© 2020 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license ( Received 6 June 2020, Revised 22 July 2020, Accepted 4 August 2020, Available online 1 September 2020. Part of the research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration [prime contract number 80NM0018D0004]. The CSU contribution to this work was supported by JPL subcontract 1439002. The University of Wisconsin/SSEC contribution to this work was supported by JPL subcontract 1577173. We declare no conflicts of interest with this research.
Funding AgencyGrant Number
Subject Keywords:OCO-3; OCO-2; ISS; Greenhouse gases; Carbon dioxide; Solar-induced chlorophyll fluorescence; Calibration
Record Number:CaltechAUTHORS:20201215-120535761
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Official Citation:Thomas E. Taylor, Annmarie Eldering, Aronne Merrelli, Matthäus Kiel, Peter Somkuti, Cecilia Cheng, Robert Rosenberg, Brendan Fisher, David Crisp, Ralph Basilio, Matthew Bennett, Daniel Cervantes, Albert Chang, Lan Dang, Christian Frankenberg, Vance R. Haemmerle, Graziela R. Keller, Thomas Kurosu, Joshua L. Laughner, Richard Lee, Yuliya Marchetti, Robert R. Nelson, Christopher W. O'Dell, Gregory Osterman, Ryan Pavlick, Coleen Roehl, Robert Schneider, Gary Spiers, Cathy To, Christopher Wells, Paul O. Wennberg, Amruta Yelamanchili, Shanshan Yu, OCO-3 early mission operations and initial (vEarly) XCO2 and SIF retrievals, Remote Sensing of Environment, Volume 251, 2020, 112032, ISSN 0034-4257, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107086
Deposited By: Tony Diaz
Deposited On:15 Dec 2020 21:42
Last Modified:16 Nov 2021 18:59

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