Global consistency check of AIRS and IASI total CO₂ column concentrations using WDCGG ground-based measurements

This article describes a global consistency check of CO₂ satellite retrieval products from the Atmospheric Infrared Sounder (AIRS) and Infrared Atmospheric Sounding Interferometer (IASI) using statistical analysis and data from the World Data Centre for Greenhouse Gases (WDCGG). We use the correlation coefficient (r), relative difference (RD), root mean square errors (RMSE), and mean bias error (MBE) as evaluation indicators for this study. Statistical results show that a linear positive correlation between AIRS/IASI and WDCGG data occurs for most regions around the world. Temporal and spatial variations of these statistical quantities reflect obvious differences between satellite-derived and ground-based data based on geographic position, especially for stations near areas of intense human activities in the Northern Hemisphere. It is noteworthy that there appears to be a very weak correlation between AIRS/IASI data and ten groundbased observation stations in Europe, Asia, and North America. These results indicate that retrieval products from the two satellite-based instruments studied should be used with great caution.