We derive regional-scale (∼104 km2) CO2 flux estimates for summer 2004 in the northeast United States and southern Quebec by assimilating extensive data into a receptor-oriented model-data fusion framework. Surface fluxes are specified using the Vegetation Photosynthesis and Respiration Model (VPRM), a simple, readily optimized biosphere model driven by satellite data, AmeriFlux eddy covariance measurements and meteorological fields. The surface flux model is coupled to a Lagrangian atmospheric adjoint model, the Stochastic Time-Inverted Lagrangian Transport Model (STILT) that links point observations to upwind sources with high spatiotemporal resolution. Analysis of CO2 concentration data from the NOAA-ESRL tall tower at Argyle, ME and from extensive aircraft surveys, shows that the STILT– VPRM framework successfully links model flux fields to regionally representative atmospheric CO2 data, providing a bridge between ‘bottom-up’ and ‘top-down’ methods for estimating regional CO2 budgets on timescales from hourly to monthly. The surface flux model, with initial calibration to eddy covariance data, produces an excellent a priori condition for inversion studies constrained by atmospheric concentration data. Exploratory optimization studies show that data from several sites in a region are needed to constrain model parameters for all major vegetation types, because the atmosphere commingles the influence of regional vegetation types, and even high-resolution meteorological analysis cannot disentangle the associated contributions. Airborne data are critical to help define uncertainty within the optimization framework, showing for example, that in summertime CO2 concentration at Argyle (107 m) is ∼0.6 ppm lower than the mean in the planetary boundary layer.
COBRA Publications
Estimating Regional Carbon Exchange in New England and Quebec by Combining Atmospheric, Ground-based and Satellite Data.” Tellus B: Chemical and Physical Meteorology, 58, 5, Pp. 344-358. DOIAbstract
. 1/2017. “
Designing Lagrangian experiments to measure regional-scale trace gas fluxes.” Journal of Geophysical Research: Atmospheres. DOIAbstract
. 7/12/2007. “
What have we learned from intensive atmospheric sampling field programs of CO2? .” Tellus B: Chemical and Physical Meteorology, 58, 5, Pp. 331-343. DOIAbstract
. 6/2/2006. “
Measuring fluxes of trace gases at regional scales by Lagrangian observations: application to the CO2 Budget and Rectification Airborne (COBRA) study.” Journal of Geophysical Research: Atmospheres. DOIAbstract
. 8/5/2004. “
The observed covariance between ecosystem carbon exchange and atmospheric boundary layer dynamics at a site in northern Wisconsin.” Journal of Geophysical Research: Atmospheres, 109, D08302. DOIAbstract
. 4/17/2004. “
Toward constraining regional-scale fluxes of CO2 with atmospheric observations over a continent: 1. Observed spatial variability from airborne platforms .” Journal of Geophysical Research: Atmospheres, 108, D24, Pp. 4756. DOIAbstract
. 12/17/2003. “
Toward constraining regional-scale fluxes of CO2 with atmospheric observations over a continent: 2. Analysis of COBRA data using a receptor-oriented framework.” Journal of Geophysical Research: Atmospheres, 108, D24, Pp. 4757. DOIAbstract
. 12/17/2003. “
Strategies for measurement of atmospheric column means of carbon dioxide from aircraft using discrete sampling.” Journal of Geophysical Research: Atmospheres, 108, D16, Pp. 4514. DOIAbstract
. 8/27/2003. “
A near-field tool for simulating the upstream influence of atmospheric observations: the Stochastic Time-Inverted Lagrangian Transport (STILT) model.” Journal of Geophysical Research: Atmospheres. DOIAbstract
. 8/19/2003. “
The CO2 Budget and Rectification Airborne Study: Strategies for Measuring Rectifiers and Regional Fluxes, in Inverse Methods in Global Biogeochemical Cycles.” . American Geophysical Union, Pp. 311-324. DOIAbstract
. 1/1/2000. “