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.