Characterization of OCO-2 and ACOS-GOSAT biases and errors for CO<sub>2</sub> flux estimates - Observatoire de Paris Access content directly
Preprints, Working Papers, ... Year : 2019

Characterization of OCO-2 and ACOS-GOSAT biases and errors for CO<sub>2</sub> flux estimates

Susan Kulawik
  • Function : Author
Sean Crowell
David Baker
  • Function : Author
Junjie Liu
  • Function : Author
Kathryn Mckain
Colm Sweeney
Sebastien Biraud
Steve Wofsy
  • Function : Author
Christopher O'Dell
  • Function : Author
Paul Wennberg
Debra Wunch
Coleen Roehl
Nicholas Deutscher
Matthäus Kiel
David Griffith
Voltaire Velazco
Justus Notholt
  • Function : Author
Thorsten Warneke
  • Function : Author
Christof Petri
Martine de Mazière
  • Function : Author
Mahesh Sha
Ralf Sussmann
  • Function : Author
Markus Rettinger
  • Function : Author
Dave Pollard
Isamu Morino
Osamu Uchino
  • Function : Author
Frank Hase
  • Function : Author
Dietrich Feist
Sébastien Roche
Kimberly Strong
Rigel Kivi
Laura Iraci
Kei Shiomi
  • Function : Author
Manvendra Dubey
Eliezer Sepulveda
  • Function : Author
Omaira Elena Garcia Rodriguez
  • Function : Author
Pauli Heikkinen
  • Function : Author
Edward Dlugokencky
  • Function : Author
Michael Gunson
  • Function : Author
Annmarie Eldering
David Crisp
Brendan Fisher
  • Function : Author
Gregory Osterman
  • Function : Author


Abstract. We characterize the magnitude of seasonally and spatially varying biases in the National Aeronautics and Space Administration (NASA) Orbiting Carbon Observatory-2 (OCO-2) Version 8 (v8) and the Atmospheric CO2 Observations from Space (ACOS) Greenhouse Gas Observing SATellite (GOSAT) version 7.3 (v7.3) satellite CO2 retrievals by comparisons to measurements collected by the Total Carbon Column Observing Network (TCCON), Atmospheric Tomography (ATom) experiment, and National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL) and U. S. Department of Energy (DOE) aircraft, and surface stations. Although the ACOS-GOSAT estimates of the column averaged carbon dioxide (CO2) dry air mole fraction (XCO2) have larger random errors than the OCO-2 XCO2 estimates, and the space-based estimates over land have larger random errors than those over ocean, the systematic errors are similar across both satellites and surface types, 0.6 ± 0.1 ppm. We find similar estimates of systematic error whether dynamic versus geometric coincidences or ESRL/DOE aircraft versus TCCON are used for validation (over land), once validation and co-location errors are accounted for. We also find that areas with sparse throughput of good quality data (due to quality flags and preprocessor selection) over land have ~double the error of regions of high-throughput of good quality data. We characterize both raw and bias-corrected results, finding that bias correction improves systematic errors by a factor of 2 for land observations and improves errors by ~ 0.2 ppm for ocean. We validate the lowermost tropospheric (LMT) product for OCO-2 and ACOS-GOSAT by comparison to aircraft and surface sites, finding systematic errors of ~ 1.1 ppm, while having 2–3 times the variability of XCO2. We characterize the time and distance scales of correlations for OCO-2 XCO2 errors, and find error correlations on scales of 0.3 degrees, 5–10 degrees, and 60 days. We find comparable scale lengths for the bias correction term. Assimilation of the OCO-2 bias correction term is used to estimate flux errors resulting from OCO-2 seasonal biases, finding annual flux errors on the order of 0.3 and 0.4 PgC/yr for Transcom-3 ocean and land regions, respectively.

Dates and versions

obspm-03991894 , version 1 (16-02-2023)



Susan Kulawik, Sean Crowell, David Baker, Junjie Liu, Kathryn Mckain, et al.. Characterization of OCO-2 and ACOS-GOSAT biases and errors for CO<sub>2</sub> flux estimates. 2023. ⟨obspm-03991894⟩
6 View
0 Download



Gmail Facebook X LinkedIn More