Schimel, David (Dave): JPL (Project Lead)
Chatterjee, Abhishek: NASA JPL (Institution Lead)
Stephens, Britton (Britt): NCAR (Institution Lead)
Project Funding:
2015 - 2018
NRA: 2014 NASA: OCO-2 Science Team for the OCO-2 Mission
Funded by NASA
Abstract:
Terrestrial and marine carbon-climate feedbacks will significantly affect future climate, and contribute uncertainty to projected temperature trends. Carbon uptake is affected by increasing CO2 and changing climate, resulting in feedbacks between the carbon and climate systems. The objective of this project is to evaluate the impact of satellite CO2 measurements on our understanding of carbon-climate feedbacks. Ecosystem models predict that increasing CO2 causes a significant tropical sink helping to balance emissions from land use/land cover change. This prediction is inconsistent with atmospheric inverse models that suggest the tropics are a source. This disagreement leads to very different carbon-climate futures, each supported by some evidence. If the land sink is dominated by mid-latitudes, then it is likely due to recovery from land use and should saturate, or slow significantly, as forests mature. Conversely, if the land sink is dominated by the tropics, it is likely due to a CO2 effect leading to continuing carbon uptake as CO2 concentrations increase. We will use OCO-2 data to test these very different spatial patterns, although sampling biases due to cloud cover and aerosol distributions will require the use of weighting and averaging techniques. Inverse model disagreements about meridional partitioning of fluxes are correlated with modeled vertical and meridional gradients. Vertical profiles and column-average gradients of CO2 can be used to filter to posterior 4-D fields from alternative inversions, and reject results with spurious fluxes. We will evaluate uncertainty in tropical interannual flux variability, and evaluate the use of glint mode for reducing confusion between tropical land and ocean fluxes. This project addresses key NASA carbon cycle goals to quantify and document how the carbon cycle is changing, and to reduce uncertainty about carbon processes for useful predictions of future changes. This project is co-sponsored by the National Center for Atmospheric Research and the NSF.
Publications:
Chatterjee, A., Gierach, M. M., Sutton, A. J., Feely, R. A., Crisp, D., Eldering, A., Gunson, M. R., O'Dell, C. W., Stephens, B. B., Schimel, D. S. 2017. Influence of El Nino on atmospheric CO
2
over the tropical Pacific Ocean: Findings from NASA's OCO-2 mission. Science. 358(6360). DOI: 10.1126/science.aam5776
More details may be found in the following project profile(s):