Net Ecosystem Exchange of Carbon over North America
Funded by NASA to David Turner, Rama Nemani, and Andy Jacobson
Project Summary
This research aims to generate daily and annual estimates of gross ecosystem exchange and net ecosystem exchange (NEE) over North America at the 1 km spatial resolution for the MODIS era using spatially distributed models. We are investigating sources of variation and uncertainty in our estimates associated with inter annual variation in climate, with how disturbance history is characterized, and with the form of the spectral data used in the scaling procedure. The approach uses a combination of prognostic and diagnostic carbon cycle models, with a focus on satellite-driven diagnostic models developed with previous NASA support. We will evaluate our continental NEE estimates by comparisons to continental scale estimates of NEE from an inversion approach based on observations of CO2 concentration (NOAA's Carbon Tracker). Our fluxes will also be input to Carbon Tracker and discrepancies between observed and predicted CO2 concentrations will be used to evaluate alternative model algorithms and inputs (e.g. MODIS vs. SeaWiFS FPAR). Because quantifying the terrestrial carbon sink in North America is of policy significance in relation to addressing the climate change issue, this research contributes to the NASA strategic goal of advancing scientific understanding of Earth and meeting societal needs. It will further the NASA research objective of improving carbon cycle models, and results will inform the next North American Carbon Program assessment of the state of the carbon cycle.
Links:
NASA Earth Exchange Data Center
Documents
- King, D.A., Turner, D.P., Ritts, W.D. 2011. Parameterization of a diagnostic carbon cycle model for continental scale application. Remote Sensing of Environment 115:1653-1664.
- Turner, D.P., Ritts, W.D., Wharton, S., Thomas, C., Monson. R., Black, T.A., Falk, M. 2009. Assessing FPAR source and parameter optimization scheme in application of a diagnostic carbon flux model. Remote Sensing of Environment 113:1529-1539.
- Nightengale, J., Morisette, J., Wolfe, R., Tan, B., Gao, F., Ederer, G., Collatz, J., Turner, D. 2009. Temporally smoothed and gap-filled MODIS land products for carbon modeling: Application of the FPAR product. International Journal of Remote Sensing 30:1083 – 1090.
- Turner, D.P., W.D. Ritts, J.M. Styles, Z. Yang, W.B. Cohen, B.E. Law, and P. Thornton. 2006. A diagnostic carbon flux model to monitor the effects of disturbance and inter annual variation in climate on regional NEP. Tellus 58B:476-490.