Zhang, Tingjun: University of Colorado, Boulder (Project Lead)
Denning, Scott: Colorado State University (Co-Investigator)
Lu, Lixin: Colorado State University (Co-Investigator)
Schaefer, Kevin: National Snow and Ice Data Center (Co-Investigator)
Project Funding:
2006 - 2009
NRA: 2005 NASA: North American Carbon Program
Funded by NASA
Abstract:
We will integrate remote sensing data sets, ground-based measurements, and numerical modeling to quantify the effects of soil temperature, soil freeze-thaw dynamics, and snow cover on seasonal to inter-annual variability in the North American terrestrial carbon cycle. Our overall goal is to understand the role of freeze-thaw processes in determining seasonal and inter-annual variability in terrestrial biomass, photosynthesis, respiration, and net CO2 fluxes over continental North America. Using remote sensing products, in situ observations, and a soil thermodynamic model, we will estimate soil temperatures and snow cover over North America at 25-km resolution for North America from 1981-2003 (23 years). We will feed these estimated soil temperatures and snow cover, along with additional remote sensing data, into an ecosystem model to estimate biomass and net carbon fluxes. Both models will use the North American Regional Reanalysis, so the resulting estimates of soil thermodynamic properties, biomass, and carbon fluxes will be optimally consistent with each other and with actual weather conditions in North America. We will statistically analyze these optimal carbon fluxes to understand the environmental drivers and biophysical responses regulating the spatial patterns and temporal variability in the North American terrestrial carbon cycle. Using standard Monte Carlo techniques, we will quantify uncertainty in our estimated carbon fluxes. Lastly, we will perturb our input data to assess the sensitivity of our estimated fluxes to long-term climate change. Our research addresses the North American Carbon Program (NACP) goals of reducing uncertainty about the buildup of greenhouse gases in the atmosphere and the dynamics of the carbon cycle. Specifically, we address the NACP goals of 1) quantifying the magnitudes and distributions of terrestrial carbon sources and sinks within North America; 2) understanding the processes controlling carbon source and sink dynamics; and 3) producing consistent analyses of the carbon budget of North America, explaining regional contributions and year-to-year variability. We will archive data products generated by this investigation at the National Snow and Ice Data Center¿s Frozen Ground Data Center for access by other NACP investigators and for general use by the scientific community.
Publications:
Schuster, P. F., Schaefer, K. M., Aiken, G. R., Antweiler, R. C., Dewild, J. F., Gryziec, J. D., Gusmeroli, A., Hugelius, G., Jafarov, E., Krabbenhoft, D. P., Liu, L., Herman-Mercer, N., Mu, C., Roth, D. A., Schaefer, T., Striegl, R. G., Wickland, K. P., Zhang, T. 2018. Permafrost Stores a Globally Significant Amount of Mercury. Geophysical Research Letters. 45(3), 1463-1471. DOI: 10.1002/2017GL075571
Chu, D., Lu, L., Zhang, T. 2007. Sensitivity of Normalized Difference Vegetation Index (NDVI) to Seasonal and Interannual Climate Conditions in the Lhasa Area, Tibetan Plateau, China. Arctic, Antarctic, and Alpine Research. 39(4), 635-641. DOI: 10.1657/1523-0430(07-501)[CHU]2.0.CO;2
Fan, G., Zhang, T., Ji, J., Li, K., Liu, J. 2007. Numerical Simulation of the Carbon Cycle Over The Tibetan Plateau, China. Arctic, Antarctic, and Alpine Research. 39(4), 723-731. DOI: 10.1657/1523-0430(07-502)[FAN]2.0.CO;2
Oelke, C., Zhang, T. 2007. Modeling the Active-Layer Depth over the Tibetan Plateau. Arctic, Antarctic, and Alpine Research. 39(4), 714-722. DOI: 10.1657/1523-0430(06-200)[OELKE]2.0.CO;2
Schaefer, K. M., Zhang, T., Tans, P. P., Stockli, R. 2007. Temperature anomaly reemergence in seasonally frozen soils. Journal of Geophysical Research. 112(D20). DOI: 10.1029/2007JD008630
Schaefer, K., Collatz, G. J., Tans, P., Denning, A. S., Baker, I., Berry, J., Prihodko, L., Suits, N., Philpott, A. 2008. Combined Simple Biosphere/Carnegie-Ames-Stanford Approach terrestrial carbon cycle model. Journal of Geophysical Research. 113(G3). DOI: 10.1029/2007JG000603
Zhang, T. 2007. Perspectives on Environmental Study of Response to Climatic and Land Cover/Land Use Change over the Qinghai-Tibetan Plateau: an Introduction. Arctic, Antarctic, and Alpine Research. 39(4), 631-634. DOI: 10.1657/1523-0430(07-513)[ZHANG]2.0.CO;2
Zhang, T., Nelson, F. E., Gruber, S. 2007. Introduction to special section: Permafrost and Seasonally Frozen Ground Under a Changing Climate. Journal of Geophysical Research. 112(F2). DOI: 10.1029/2007JF000821
2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)
- Can we avoid the permafrost carbon tipping point?
-- (Kevin M. Schaefer, Tingjun Zhang, Lori Bruhwiler, Andrew Barrett, Zhuxiao Li)
[abstract]
2008 NASA Carbon Cycle & Ecosystems Joint Science Workshop Posters
- Snow, soil freeze/thaw, and the carbon cycle
-- (Kevin M Schaefer, Tingjun Zhang, Lixin Lu, Ian Baker)
[abstract]
[poster]
- Spatial and Temporal Variability of Seasonal Snow Cover in North America
-- (Tingjun Zhang, James McCreight, Kevin Schaefer, Lixin Lu, Andrew Etringer)
[abstract]
- The Interactions Between SiBCASA-simulated Surface Fluxes, Carbon Pools, Biomass, and North American Climate Variability
-- (Lixin Lu, Kevin Schaefer, Tingjun Zhang, Ian Baker, Scott Denning)
[abstract]
More details may be found in the following project profile(s):