Atmospheric inverse modeling to constrain regional‐scale CO₂ budgets at high spatial and temporal resolution

Abstract

[1] We present an inverse modeling framework designed to constrain CO 2 budgets at regional scales. The approach captures atmospheric transport processes in high spatiotemporal resolution by coupling a mesoscale model with Lagrangian Stochastic backward trajectories. Terrestrial biosphere CO 2 emissions are generated through a simple diagnostic flux model that splits the net ecosystem exchange into its major components of gross primary productivity and autotrophic and heterotrophic respirations. The modeling framework assimilates state-of-the-art data sets for advected background CO 2 and anthropogenic fossil fuel emissions as well as highly resolved remote sensing products. We introduce a Bayesian inversion setup, optimizing a posteriori flux base rates for surface types that are defined through remote sensing information. This strategy significantly reduces the number of parameters to be optimized compared with solving fluxes for each individual grid cell, thus permitting description of the surface in a very high resolution. The model is tested using CO 2 concentrations measured in the fall and winter of 2006 at two AmeriFlux sites in Oregon. Because this database does not cover a full seasonal cycle, we focus on conducting model sensitivity tests rather than producing quantitative CO 2 flux estimates. Sensitivity tests on the influence of spatial and temporal resolution indicate that optimum results can be obtained using 4 h time steps and grid sizes of 6 km or less. Further tests demonstrate the importance of dividing biome types by ecoregions to capture their different biogeochemical responses to external forcings across climatic gradients. Detailed stand age information was shown to have a positive effect on model performance.Citation: Göckede, M., A. M. Michalak, D. Vickers, D. P. Turner, and B. E. Law (2010), Atmospheric inverse modeling to constrain regional-scale CO 2 budgets at high spatial and temporal resolution,

Network design for mesoscale inversions of CO₂ sources and sinks

“…Mesoscale atmospheric inversions were used in several studies as a promising tool to monitor and estimate regional flux balances at high resolution (Lauvaux et al, 2009;Schuh et al, 2010;Go¨ckede et al, 2010a). Though errors in the atmospheric transport model and at the boundaries limit the potential of the method (Go¨ckede et al, 2010b;Lauvaux et al, 2012), mesoscale inverse systems have shown consistent improvements from prior fluxes over short periods of time (Lauvaux et al, 2009), and at the annual time scale over the region (Schuh et al, 2010).…”

Analysis of the potential of near-ground measurements of CO<sub>2</sub> and CH<sub>4</sub> in London, UK, for the monitoring of city-scale emissions using an atmospheric transport model

“…This may explain the different sign of the modeldata discrepancies during night-time between the urban sites and the other sites. We thus restrict the remaining analyses in this paper to the period between 12:00 and 17:00 UTC, wherein we can expect the boundary layer to be well developed, to have a stable height and to exert minimum influence on the variations in gas mole fractions (Geels et al, 2007;Göckede et al, 2010).…”

Atmospheric CO<sub>2</sub> monitoring with single-cell NDIR-based analyzers

“…In the United States, versions of these systems are currently operated by PSU at Ameriflux sites located in Canaan Valley (WV), Chestnut Ridge (TN), Missouri Ozarks (MO), and Mead (NE), and operated by NCAR as part of the Regional Atmospheric Continuous CO 2 Network in the Rocky Mountains (Rocky RACCOON, raccoon.ucar.edu) at Fraser Experimental Forest (CO), Niwot Ridge T-Van Site (CO), Storm Peak Laboratory (CO), Hidden Peak (UT), and Roof Butte (AZ). Instruments based on the designs described in this paper are also deployed in Oregon (Göeckede et al, 2010) and at Morgan-Monroe State Forest (IN) (Schmid et al, 2000).…”