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Updated: Jun 17, 2026
09:05
Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites
Published on: June 24, 2019
Improved latitudinal carbon budgets from global airborne surveys
Britton B Stephens1, Yuming Jin1, Colm Sweeney2
1NSF National Center for Atmospheric Research, Earth Observing Laboratory, Boulder, CO 80301.
Summary
Accurate global carbon flux data is crucial for climate projections. This study refines atmospheric CO2 flux estimates using airborne data, revealing a significant northern extratropical carbon sink and a tropical land source, challenging current models.
Area of Science:
- Atmospheric Science
- Earth System Science
- Climate Science
Background:
- Accurate global carbon flux data is essential for climate change modeling.
- Existing atmospheric CO2 inverse models show significant divergence in flux estimates.
- Methodological limitations and biases in models/observations contribute to uncertainty.
Purpose of the Study:
- To evaluate and refine inverse model estimates of global CO2 exchange using airborne observations.
- To reduce uncertainties in the latitudinal partitioning of carbon fluxes.
- To investigate discrepancies between model-based and observation-based carbon flux estimates.
Main Methods:
- Utilized airborne CO2 observations from NASA's Atmospheric Tomography Mission (ATOMOS).
- Applied emergent concentration-flux relationships as constraints to refine Orbiting Carbon Observatory (OCO) v10 Model Intercomparison Project (MIP) estimates.
- Subtracted independent estimates of fossil-fuel emissions and air-sea gas exchange to derive residual land fluxes.
Main Results:
- Refined flux estimates reduced zonal total flux uncertainties by 46-56% compared to the full OCO v10 MIP ensemble.
- Derived residual land fluxes indicate a large northern extratropical sink, a small southern extratropical sink, and a small tropical source.
- Airborne-derived tropical land source contradicts large tropical sink estimates from terrestrial models.
Conclusions:
- The study highlights significant discrepancies in tropical carbon cycle understanding.
- A large northern extratropical sink suggests potential underestimation of land uptake or process model bias.
- Further research is needed to reconcile differences between atmospheric inverse models and terrestrial process models.
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