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Improving NASA GEOS Atmospheric CO2 Simulations by Calibrating CASA Surface Fluxes with an Empirical SinkWith the adoption of the Paris climate accord, efforts to monitor and understand both anthropogenic and natural carbon sources and sinks are increasing across the world. Given their low latency and global coverage, satellite observations of atmospheric carbon dioxide (CO2) are poised to make important contributions to this field. The combination of satellite data and high resolution global models can be used to monitor changes in carbon fluxes and to evaluate the consistency of nationally reported emissions estimates in support of multiple stakeholder communities. However, a consistent challenge to such work has been the high latency of surface carbon flux estimates, which are often not available for a year or more. This presentation describes the construction of surface carbon flux estimates meant to improve the near real time simulation of atmospheric CO2 with NASA's Goddard Earth Observing System (GEOS) general circulation model. The surface flux estimates begin with a collection of bottom-up fluxes which incorporate satellite measurements in their construction, e.g. vegetation indices in the Carnegie-Ames-Stanford Approach (CASA) and nighttime lights in the Open-source Data Inventory for Anthropogenic CO2 (ODIAC). From there, we take the additional step of using an empirical sink to calibrate terrestrial net biospheric exchange (NBE) to estimated values from atmospheric inversion systems. This approach removes a known, systematic bias in predicted atmospheric mixing ratios. Using these fluxes in a free running simulation, the model is able to reproduce in situ measurements with the same skill as when it uses gridded fluxes from a flux inversion system. Using these fluxes as a prior in an assimilation system, e.g. one incorporating retrievals of column CO2 from the Orbiting Carbon Observatory 2 (OCO-2), allows the analysis to capture variability in CO2 on scales that would be missed otherwise. This approach supports NASA's capability to forecast atmospheric CO2 up to two weeks in advance by leveraging a GEOS system used to produce quasi-operational weather analyses and forecasts, providing a valuable new tool to the carbon monitoring research and applications communities.
Document ID
20180008662
Acquisition Source
Goddard Space Flight Center
Document Type
Presentation
Authors
Weir, B. (Universities Space Research Association (USRA) Greenbelt, MD, United States)
Ott, L. E. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Collatz, G. J. (Emeritus)
Poulter, B. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kawa, S. R. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Chatterjee, A. (Universities Space Research Association (USRA) Greenbelt, MD, United States)
Oda, T. (Universities Space Research Association (USRA) Greenbelt, MD, United States)
Pawson, S. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
December 19, 2018
Publication Date
December 10, 2018
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN64185
Meeting Information
Meeting: AGU 2018 Fall Meeting
Location: Washington, D.C.
Country: United States
Start Date: December 10, 2018
End Date: December 14, 2018
Sponsors: American Geophysical Union (AGU)
Funding Number(s)
CONTRACT_GRANT: NNG11HP16A
Distribution Limits
Public
Copyright
Public Use Permitted.

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