Using CO2 spatial variability to quantify representation errors of satellite CO2 retrievals

[i] Satellite measurements of column-averaged CO 2 dry-air mole fraction (X CO2 ) will be used in inversion and data assimilation studies to improve the precision and resolution of current estimates of global fluxes of CO 2 . Representation errors due to the mismatch in spatial scale between satellite retrievals and atmospheric transport models contribute to the uncertainty associated with flux estimates. This study presents a statistical method for quantifying representation errors as a function of the underlying spatial variability of X CO2 and the spatial distribution of retrieved soundings, without knowledge of the true X CO2 distribution within model gridcells. Representation errors are quantified globally using regional X CO2 spatial variability inferred using the PCTM/GEOS-4 model and a hypothetical atmospheric transport model with 1° x 1° resolution, 3 km 2 retrieval footprints, and two different sounding densities.

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