Project Funding: 2011 - 2015

NRA: 2010 NASA: Carbon Cycle Science   

Funded by NASA

Abstract:
Terrestrial ecosystems are buffering human-induced climate change by absorbing about one fourth of the carbon dioxide (CO2) emitted into the atmosphere by fossil fuel burning. This terrestrial storage of CO2, however, is difficult to measure. Quantification of these fluxes is essential to guide land management and climate change mitigation efforts. Atmospheric budgets, known as 'inversions,' provide one important means of quantifying forest carbon storage. At present, however, regional atmospheric budgets have limited accuracy and precision due to incomplete knowledge of atmospheric transport, and a limited number of high-quality measurements of the atmospheric concentration of CO2. The first component of this study will use data from the North American Carbon Program Midcontinent Intensive (MCI) regional experiment, which took place in the upper Midwest of the US from 2007-2009. We will use data from this experiment to evaluate, quantify, and reduce the impact of uncertainty in atmospheric transport on our ability to make inverse flux estimates. To do this we will run many different versions of a widely tested atmospheric transport model to simulate atmospheric winds and CO2 concentrations in the MCI region. Each model version will represent a plausible realization of atmospheric conditions. We will then compare the multiple model results to a suite of regional measurements of atmospheric properties and CO2 concentrations to identify more and less realistic versions of the model, and to quantify the range of uncertainty that remains among the plausible model versions. We will then use this knowledge to improve our estimates of the CO2 balance of the upper Midwest. The uncertainty in these flux estimates will be more realistic and smaller than past estimates. Further, we will use our model results to evaluate how much space-based measurements of the column density of CO2, as will be obtained from the Orbiting Carbon Observatory-2 (OCO-2), would improve our regional CO2 flux estimates. The second stage of this study will apply these methods to derive greatly improved estimates of CO2 and methane (CH4) fluxes from the Gulf Coast region of the southeastern (SE) US. The forests of the southeastern United States are highly productive, heavily managed, and susceptible to climate change. These forests represent a dynamic element of the carbon budget of the United States. Atmospheric inverse studies and terrestrial carbon cycle models, however, do not yield consistent findings regarding land-atmosphere fluxes of carbon in this region. We will deploy the 'ring of towers' technology that we demonstrated in the NACP MCI regional study to these SE US forests. Five towers in the SE US will be instrumented to measure CO2 and CH4 concentrations, and will complement 6 tower-based measurements that already exist in the region. These measurements will be deployed to coincide with the launch of OCO-2. Data from both tower and satellite will be combined to estimate the forest-atmosphere fluxes of CO2 and CH4 from the southeastern, Gulf coast states. Our improved understanding of atmospheric transport will be utilized to improve these estimates. We will then compare our results to independent estimates obtained from biomass inventories and biogeochemical models to see if these estimates converge. Discussions with regional forest and greenhouse gas managers and policy makers will be held throughout the project to determine their needs and the ability of our developing methodology to meet their needs.

Publications:

Lauvaux, T., Davis, K. J. 2014. Planetary boundary layer errors in mesoscale inversions of column-integrated CO2measurements. Journal of Geophysical Research: Atmospheres. 119(2), 490-508. DOI: 10.1002/2013JD020175

Miles, N. L., Richardson, S. J., Davis, K. J., Lauvaux, T., Andrews, A. E., West, T. O., Bandaru, V., Crosson, E. R. 2012. Large amplitude spatial and temporal gradients in atmospheric boundary layer CO2mole fractions detected with a tower-based network in the U.S. upper Midwest. Journal of Geophysical Research: Biogeosciences. 117(G1). DOI: 10.1029/2011JG001781

Wu, L., Bocquet, M., Chevallier, F., Lauvaux, T., Davis, K. 2013. Hyperparameter estimation for uncertainty quantification in mesoscale carbon dioxide inversions. Tellus B: Chemical and Physical Meteorology. 65(1), 20894. DOI: 10.3402/tellusb.v65i0.20894

2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• The Gulf Coast Intensive: Progress towards high-fidelity, regional-scale inverse estimates of the North American terrestrial carbon budget.   --   (Kenneth James Davis, Martha Butler, George James Collatz, Aijun Deng, Liza Ivelisse Diaz-Isaac, Thomas Lauvaux, Natasha Miles, Caroline Normile, Stephen M Ogle, Scott Richardson, Andrew Schuh, Tristram O. West, Christopher A Williams)   [abstract]

2013 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• The impact of atmospheric transport uncertainty on inverse studies of CO2 sources and sinks in regional atmospheric intensives   --   (Kenneth James Davis, Liza Ivelisse Diaz-Isaac, Thomas Lauvaux, Natasha L Miles, Scott J Richardson)   [abstract]

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Model-Data Comparison of Mid-Continental Intensive Field Campaign Atmospheric CO2 Mixing Ratios   --   (Liza Ivelisse Diaz, Kenneth James Davis, Thomas Lauvaux, Natasha Miles, Scott Richardson, Andy Jacobson, Arlyn Andrews)   [abstract]

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

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