Title: What eddy-covariance measurements tell us about prior land flux errors in CO2-flux inversion schemes
Authors: CHEVALLIER FREDERICTAO WANGCIAIS PHILIPPEMAIGNAN F.BOCQUET MARCALTAF ARAIN M.CESCATTI ALESSANDROCHEN JIQUANDOLMAN A. JOHANNESLAW BEVERLY E.MARGOLIS HANKMONTAGNANI LEONARDOMOORS EDDY
Citation: GLOBAL BIOGEOCHEMICAL CYCLES vol. 26 no. 1 p. GB1021
Publisher: AMER GEOPHYSICAL UNION
Publication Year: 2012
JRC N°: JRC68617
ISSN: 0886-6236 (online)
URI: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010GB003974
http://publications.jrc.ec.europa.eu/repository/handle/JRC68617
DOI: 10.1029/2010GB003974
Type: Articles in periodicals and books
Abstract: To guide the future development of CO2-atmospheric inversion modeling systems, we analyzed the errors arising from prior information about terrestrial ecosystem fluxes. We compared the surface fluxes calculated by a process-based terrestrial ecosystem model with daily averages of CO2 flux measurements at 156 sites across the world in the FLUXNET network. At the daily scale, the standard deviation of the model-data fit was 2.5 gC•m-2•d-1; temporal autocorrelations were significant at the weekly scale (> 0.3 for lags less than four weeks), while spatial correlations were confined to within the first few hundred kilometers (< 0.2 after 200 km). Separating out the plant functional types did not increase the spatial correlations, except for deciduous broad-leaved forests. Using the statistics of the flux measurements as a proxy for the statistics of the prior flux errors was shown not to be a viable approach. A statistical model allowed us to upscale the site-level flux error statistics to the coarser spatial and temporal resolutions used in regional or global models. This approach allowed us to quantify how aggregation reduces error variances, while increasing correlations. As an example, for a typical inversion of grid-point (300 km x 300 km) monthly fluxes, we found that the prior flux error follows an approximate e-folding correlation length of 500 km only, with correlations from one month to the next as large as 0.6.
JRC Directorate:Space, Security and Migration

Files in This Item:
There are no files associated with this item.


Items in repository are protected by copyright, with all rights reserved, unless otherwise indicated.