Fusion of space-based CO2 products and its comparison with other available CO2 estimates

Currently, ascertaining and quantifying the global distribution of carbon dioxide from space-based measurements are greatly valuable for understanding the causes of global warming and predicting the tendency of climate change. Nevertheless, the number of valid XCO₂ data points from a single space-based sensor is generally limited on the earth. Based on this problem, a fused XCO₂ dataset is used to generate a continuous spatio-temporal distribution of global CO₂ concentration by combining GOSAT with SCIAMACHY in this study. And this dataset is also compared with a data assimilation system Carbon Tracker as well as ground-based TCCON sites. The results reveal that the spatial coverage of the fused data is wider than individual space-based XCO₂ measurements (GOSAT or SCIAMCHY) on the global scale. Meanwhile, compared to that of GOSAT or SCIAMACHY, the correlation between the fused data and Carbon Tracker is relatively better. In addition, the fused data show a good agreement with CO₂ retrieval of ACOS and BESD as well as that of TCCON sites although a little biases exist.