Atmospheric Carbone monoxide (CO) volume mixing ratios (VMR) retrieved by the Measurement of Pollution in the Troposphere (MOPITT) and Atmospheric Infrared Sounder (AIRS) instruments were used to monitor local emissions and compared over Iraq during the winter and spring of 2012. A comparison and cross reference are necessary to understand the impacts of these two data sets to the scientific conclusions developed from them, due to their simultaneous measurements of CO. The monthly CO VMR from MOPITT surface and AIRS 800 hpa are compared between the two instruments over Iraq for both direct comparison and the comparison using the same a priori profile for the period from 1 January to 31 December 2012. The CO VMR examination of the fluctuated, related to the mean CO background measured by each instrument, shows large-scale serendipitous spatial properties develop along the year. The regional CO VMR differences between two instruments were 5-35 ppbv and it’s large for higher CO plumes and smaller for clean pristine desert environment. Both instruments observed enhancements of CO over the mountains and agreed with low CO over the southern region. Also, the time series of the monthly CO anomalies reveal a seasonal cycle signal, with high in winter and low in summer, due to meteorological condition, geographic nature of the regions and characteristic of the lower and upper troposphere to which MOPITT and AIRS are respectively sensitive to. This comparison demonstrates that there is a general consistency when considering the different vertical sensitivities of the instruments. The satellites observation efficiently shows the spatial and temporal variations of CO for the considered study area.
