Investigation of the consistency of atmospheric CO2 retrievals from different space-based sensors: Intercomparison and spatiotemporal analysis

In recent years, global warming caused by emission of CO2 has attracted considerable attention from the public. Although the measurements from AIRS, GOSAT, SCIAMACHY and IASI have been frequently used to derive atmospheric CO2 concentration, comprehensive quantification of the differences among these CO2 products is still not fully investigated yet. In this paper, a series of strategies have been proposed to allow the CO2 products from different instruments to be physically inter-comparable. Based on this, these CO2 products are inter-compared in terms of magnitude and their spatiotemporal distributions. The results reveal that the correlations among these CO2 products are relatively weak, and some discrepancies are detected in terms of the CO2 spatiotemporal characteristics, demonstrating more efforts should be made in the future to improve the retrievals of CO2. Their spatial coverage differences reflected in this study imply the great necessity to generate consistent products with improved spatial and temporal continuities by combining these CO2 measurements.