Project Funding: 2006 - 2009

NRA: 2005 NASA: North American Carbon Program   

Funded by NASA

Abstract:
This project will address the NACP's stated goals of (i) developing 'quantitative scientific knowledge, robust observations, and models to determine emissions and uptake of CO2 [...] and the factors regulating these processes, in North America' and (ii) developing 'the scientific basis to implement full carbon accounting, including natural and anthropogenic fluxes of CO2 [...] on regional and continental scales' (Denning et al. 2005). The overall goal of the project is to use remotely-sensed and atmospheric data in a geostatistical inverse modeling framework to quantify the North-American surface fluxes of CO2 for two years (2004-2005) with unprecedented spatial and temporal resolution. The seven main steps of the study needed to achieve this goal are: (1) to develop a database of remote-sensing datasets related to carbon cycling, (2) to improve the representation of atmospheric transport for regional-scale inversions by generating mass-conserving wind products, quantifying vertical transport errors, and using this information to run the STILT atmospheric model, originally designed to extract information on the influence of surface processes from atmospheric observations in the midst of strong, highly-varying fluxes, (3) to assess and compile atmospheric data to be used in the inversions, primarily continuous measurements taken at tall-tower sites, (4) to calculate influence functions to quantify the sensitivity of atmospheric data to underlying fluxes, using STILT, (5) to extend geostatistical techniques for application to regional inverse modeling, including methods for incorporating both spatial and temporal flux correlations and error covariances, and statistical techniques for testing the influence of auxiliary data on fluxes as seen by atmospheric data, (6) use geostatistical inverse modeling to estimate fluxes over North America and the influence of auxiliary environmental data on these fluxes on several timescales ranging from the diurnal cycle to monthly averaged estimates, and (7) to disseminate research results to the NACP and broader scientific community. We intend to achieve this goal without relying on prior flux estimates, while rigorously quantifying the magnitude and spatiotemporal covariance of the various components of model, measurement, and flux errors. In addition, we will evaluate the sensitivity of the inferred fluxes to available remotely-sensed environmental datasets, providing the process-based understanding needed to improve bottom-up inventories and biospheric models, thereby enabling more accurate flux accounting.

Publications:

Michalak, A.M. (2008), "A geostatistical fixed-lag Kalman smoother for atmospheric inversions," Atmospheric Chemistry and Physics, 8, 6789-6799.

Gourdji, S. M., Mueller, K. L., Schaefer, K., Michalak, A. M. 2008. Global monthly averaged CO2fluxes recovered using a geostatistical inverse modeling approach: 2. Results including auxiliary environmental data. Journal of Geophysical Research. 113(D21). DOI: 10.1029/2007JD009733

Mueller, K. L., Gourdji, S. M., Michalak, A. M. 2008. Global monthly averaged CO2fluxes recovered using a geostatistical inverse modeling approach: 1. Results using atmospheric measurements. Journal of Geophysical Research. 113(D21). DOI: 10.1029/2007JD009734

Gourdji, S. M., Hirsch, A. I., Mueller, K. L., Yadav, V., Andrews, A. E., Michalak, A. M. 2010. Regional-scale geostatistical inverse modeling of North American CO<sub>2</sub> fluxes: a synthetic data study. Atmospheric Chemistry and Physics. 10(13), 6151-6167. DOI: 10.5194/acp-10-6151-2010

Mueller, K. L., Yadav, V., Curtis, P. S., Vogel, C., Michalak, A. M. 2010. Attributing the variability of eddy-covariance CO2flux measurements across temporal scales using geostatistical regression for a mixed northern hardwood forest. Global Biogeochemical Cycles. 24(3). DOI: 10.1029/2009GB003642

Yadav, V., Mueller, K. L., Dragoni, D., Michalak, A. M. 2010. A geostatistical synthesis study of factors affecting gross primary productivity in various ecosystems of North America. Biogeosciences. 7(9), 2655-2671. DOI: 10.5194/bg-7-2655-2010

Huntzinger, D. N., Gourdji, S. M., Mueller, K. L., Michalak, A. M. 2011. A systematic approach for comparing modeled biospheric carbon fluxes across regional scales. Biogeosciences. 8(6), 1579-1593. DOI: 10.5194/bg-8-1579-2011

Gourdji, S. M., Mueller, K. L., Yadav, V., Huntzinger, D. N., Andrews, A. E., Trudeau, M., Petron, G., Nehrkorn, T., Eluszkiewicz, J., Henderson, J., Wen, D., Lin, J., Fischer, M., Sweeney, C., Michalak, A. M. 2012. North American CO<sub>2</sub> exchange: inter-comparison of modeled estimates with results from a fine-scale atmospheric inversion. Biogeosciences. 9(1), 457-475. DOI: 10.5194/bg-9-457-2012

Huntzinger, D. N., Post, W. M., Wei, Y., Michalak, A. M., West, T. O., Jacobson, A. R., Baker, I. T., Chen, J. M., Davis, K. J., Hayes, D. J., Hoffman, F. M., Jain, A. K., Liu, S., McGuire, A. D., Neilson, R. P., Potter, C., Poulter, B., Price, D., Raczka, B. M., Tian, H. Q., Thornton, P., Tomelleri, E., Viovy, N., Xiao, J., Yuan, W., Zeng, N., Zhao, M., Cook, R. 2012. North American Carbon Program (NACP) regional interim synthesis: Terrestrial biospheric model intercomparison. Ecological Modelling. 232, 144-157. DOI: 10.1016/j.ecolmodel.2012.02.004

2010 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• Results from a Regional Geostatistical Inversion over North America for 2004   --   (Sharon M Gourdji, Kim L Mueller, Vineet Yadav, Deborah Huntzinger, Adam Hirsch, Arlyn Andrews, Michael Trudeau, Marc Fischer, William Munger, Steven Wofsy, Douglas Worthy, Anna Michalak)   [abstract]
• Attributing the Variability of Gross Ecosystem Exchange (GEE) Using Environmental Data   --   (Vineet Yadav, Kim L. Mueller, Anna M. Michalak, Deborah Huntzinger)   [abstract]
• The Influence of North American Carbon Flux Spatial Distribution on the Temporal Variability of Atmospheric Carbon Dioxide   --   (Deborah N Huntzinger, Sharon M Gourdjii, Anna M Michalak)   [abstract]   [poster]

2008 NASA Carbon Cycle & Ecosystems Joint Science Workshop Posters

• Quantification of Spatial and Temporal Variability of North American Biospheric Carbon Flux Estimates   --   (Deborah N. Huntzinger, Kim L. Mueller, Anna M. Michalak)   [abstract]   [poster]
• Estimating North American CO₂ Fluxes within a Geostatistical Inverse Modeling Framework: Preliminary Pseudo-data Results   --   (Sharon Gourdji, Adam Hirsch, Kim Mueller, Deborah Huntzinger, Arlyn Andrews, Anna M Michalak)   [abstract]   [poster]

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile
• North American Carbon Program (NACP) Project Profile