Project Funding: 2015 - 2018

NRA: 2014 NASA: OCO-2 Science Team for the OCO-2 Mission   

Funded by NASA

Abstract:
There is a wide range of variability across the suite of CMIP terrestrial ecology models, which remains due to a dearth of precise observations with global coverage . With the launch of OCO-2, there is great potential for constraining global net carbon flux with measurements of XCO2 and gross primary productivity (GPP) using solar induced fluorescence (SIF). In this proposal, we will provide optimized estimates of net carbon flux and GPP, and in turn use these estimates to correct parameterizations of carbon cycle processes in the Community Land Model (CLM). This cross-disciplinary project is possible through collaboration between team members with expertise in flux estimation with XCO2 (Crowell, Schuh, Chatterjee and Rayner), as well as calibration of carbon cycle process models (Rayner and Luo). The potential for estimates of GPP from retrievals of SIF is at the cutting edge of carbon cycle science, and the ability of the team to perform this task is made possible through our team's expertise in the retrieval of SIF and data assimilation techniques for using it (Frankenberg and Rayner). Specifically, optimal estimates of global net carbon flux will be computed by Crowell using a 4DVAR algorithm that are consistent with retrievals of XCO2 from O'Dell and the OCO-2 retrieval team. Independent estimates of GPP will be provided by Rayner utilizing functional models that relate GPP and SIF, incorporating retrievals of SIF provided by Frankenberg. Micro-scale estimates will be provided using Lagrangian techniques by Schuh. Each of these products will be assimilated into CLM using a Monte Carlo Markov Chain algorithm, with the end result being a calibrated parameterization set, whose output of total biospheric flux will drive a transport model to generate concentrations that can be compared with independent measurements from TCCON. This proposal is significant in the context of the solicitation, specifically 'Performing flux inversion analysis using OCO-2 data, including the assessment of retrieval errors on flux inversions' and 'New research and innovative analyses using data from OCO-2', whereby not only flux estimates themselves are improved, but the underlying process understanding is also brought into better agreement with observations.

Publications:

Crowell, S., Baker, D., Schuh, A., Basu, S., Jacobson, A. R., Chevallier, F., Liu, J., Deng, F., Feng, L., McKain, K., Chatterjee, A., Miller, J. B., Stephens, B. B., Eldering, A., Crisp, D., Schimel, D., Nassar, R., O'Dell, C. W., Oda, T., Sweeney, C., Palmer, P. I., Jones, D. B. A. 2019. The 2015-2016 carbon cycle as seen from OCO-2 and the global in situ network. Atmospheric Chemistry and Physics. 19(15), 9797-9831. DOI: 10.5194/acp-19-9797-2019