Estimating carbon fluxes for North America from a joint inversion for CO2 and COS sing STILT

Author: Thomas Nehrkorn, and H. Chen
December 7, 2011
Poster presentation
AGU Fall Meeting 2011

H. Chen, G. Petron, M.E. Trudeau, A. Karion, F.T. Koch, R. Kretschmer, C. Gerbig, J.E. Campbell, J.A. Berry, I.T. Baker, Thomas Nehrkorn, Janusz Eluszkiewicz, B.R. Miller, S.A. Montzka, A.R. Jacobson, C. Sweeney, A.E. Andrews, P.P. Tans (2011) Estimating carbon fluxes for North America from a joint inversion for CO2 and COS sing STILT. AGU Fall Meeting 2011.

Understanding biospheric CO2 fluxes is paramount if climate studies are to be able to analyze the response of terrestrial ecosystems to climate change and monitor fossil fuel emissions reductions. Carbonyl sulfide (COS) may be a useful tracer to provide a constraint on photosynthesis [gross primary production (GPP)]. Here we simulate both COS and CO2 using the Stochastic Time-Inverted Lagrangian Transport (STILT) model coupled with various biospheric fluxes, such as fluxes estimated from the Vegetation Photosynthesis and Respiration Model (VPRM), CarbonTracker, and from the Carnegie-Ames-Stanford Approach (CASA) model.

The STILT model is driven by Weather Research and Forecast (WRF) meteorological fields. The WRF-STILT system is compared with the STILT driven by the ECMWF (European Center for Medium range Weather Forecasting) meteorology for the North American domain. This study uses measurements of COS and CO2 in 2008 from the NOAA/ESRL tall tower and aircraft air sampling networks, with ~ 6,000 observations in total. Biospheric COS fluxes will be estimated from a GPP-based model coupled with the GPP estimates from above mentioned biosphere models. Soil uptakes of COS are derived from a biosphere model (SiB) that assimilates the soil moisture and temperature. Estimation of other COS fluxes, such as anthropogenic, biomass burning are based on existing analyses of temporal and spatial variations. Empirical boundary curtains are built based on observations at the NOAA/ESRL marine boundary layer stations and from aircraft vertical profiles, and are utilized as the lateral boundary conditions for COS and CO2 for North America.

Comparison of the simulations for both COS and CO2 using different biospheric fluxes provides an opportunity to assess the performance of both the biospheric models and the representation of atmospheric transport. In addition, we will estimate the carbon fluxes for North America from a joint inversion for COS and CO2 in a Bayesian synthesis framework, in which the GPP and Respiration are separately optimized for each vegetation type.