A Preliminary Assessment of Orbiting Carbon Observatory-2 (OCO-2) Measurements Using TCCON Data
Paul O Wennberg1, Brenden Fisher2, Coleen Marie Roehl3, Debra Wunch4, Gregory B Osterman5, Annmarie Eldering2, Bret J Naylor2, Hai Nguyen5, Lukas Mandrake5, Christopher O'Dell6, Christian Frankenberg7, Vijay Natraj2, Thomas Taylor7, Mike Smyth8, Dr. David Crisp9, Harold R Pollock2, Vivienne Payne2, Michael R Gunson2, Ross J Salawitch10 and TCCON Partners, (1)California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, United States, (2)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (3)California Institute of Technology, Pasadena, CA, United States, (4)University of Toronto, Department of Physics, Toronto, ON, Canada, (5)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, United States, (6)Colorado State University, Cooperative Institute for Research in the Atmosphere, Fort Collins, United States, (7)NASA Jet Propulsion Laboratory, Pasadena, United States, (8)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (9)Crisp Spectra LLC, Sedona, United States, (10)University of Maryland College Park, Department of Chemistry and Biochemistry, College Park, MD, United States
Abstract:
The NASA Orbiting Carbon Observatory-2 (OCO-2) successfully launched from Vandenberg Air Force Base in California on July 2, 2014. The mission provides remotely-sensed measurements of the column-averaged dry air mole fraction of carbon dioxide from space. In order to insure the quality of the space-based observations, a detailed validation program was developed for the original OCO mission. During the time period between the original OCO launch failure and the successful launch of OCO-2, that validation methodology was tested and refined using data from the Japanese Greenhouse gases Observing SATellite (GOSAT) as part of the NASA Atmospheric CO
2 Observations from Space (ACOS) project.
At the core of the OCO-2 validation plan are comparisons of the satellite data to observations from Total Carbon Column Observation Network (TCCON), a network of ground based Fourier Transform Spectrometers. The TCCON instruments provide “ground truth”, allowing for determination of bias in the space-based observations. The TCCON observations are, in turn, traceable to the World Meteorological Organization (WMO) standards through aircraft and balloon-borne profile observations at the TCCON locations.
OCO-2 is capable of making measurements in three observation modes: nadir; glint; and target. The initial operational mode for OCO-2 alternates between nadir and glint mode every 16 days with target mode observations initiated by commanding the spacecraft to point to specific surface location. Of the 19 locations that can be observed by OCO-2 in target mode, 18 are TCCON sites. The decision to target a specific TCCON site is based on a variety of criteria, including the local weather forecast, the operational status of the station, and the time since previous observation of that site. In addition, the coincidence criteria to utilize in comparison between the satellite and TCCON measurements have been refined during the ACOS project and will be utilized to compare OCO-2 nadir and glint observations with TCCON data.
In this presentation, we will show preliminary comparisons between OCO-2 and TCCON, using data from all satellite observing modes.
