Inversion of Column-CO2 Observations from Space Using a High Resolution Inverse Model

An inverse modelling approach is developed for surface source estimation of CO₂ fluxes at higher spatial resolution for large number of smaller source regions. The annual mean fluxes are retrieved for 432 source regions, each region's size of 10 x 15 degrees latitude-longitude, assuming availability of the CO₂ observations on the ground network and column abundance observed by satellite sensor. This inverse model is used to evaluate the utilities of columnar measurements of CO₂ in surface source estimations at regional scale. No prior flux pattern and correlation between regions is assumed. It can be concuded that the inverse model should utilize source regions that are small enough, approximately of the size of source footprints at surface measurement station, for a fair comparison of the satellite data utility against the ground-based observations. The columnar satellite CO₂ concentration measurements are effective in flux estimate uncertainty reductions if global coverage and total columns can be obtained with sufficient accuracy. The partial column measurements (above the PBL) and observations only over the ocean produce only minor contribution to constraining the inverse model estimates of terrestrial CO2 fluxes.