From the Atmospheric Infrared Sounder (AIRS) we are able to derive a mid-tropospheric CO2 research data product that is global in coverage (day/night, polar/land/ocean, clear and cloudy) at a nominal resolution 1x1 degree. The distribution of middle tropospheric CO2 is observed to be strongly influenced by surface sources and large scale circulations such as the mid latitude jet streams and by synoptic weather systems, most notably in the summer hemisphere. The results provide the means to understand the sources and sinks and the lifting of CO2 from surface layers into the free troposphere. These processes are not adequately represented in three chemistry transport models that are been used to study carbon budgets.

We apply the method of Vanishing Partial Derivative (VPD) [Chahine et al., 2005] to retrieve daily the mid-tropospheric CO2 over several years of measurements by AIRS and observe substantial spatiotemporal variability. We assess the accuracy of our retrievals by comparison with available collocated in situ observations from aircraft and with published data from an upward viewing Fourier Transform Spectrometer (FTIR) at Park Falls, WI; Bremen, Germany and Spitsbergen, Norway. There is good agreement between AIRS retrievals and aircraft observations; the standard deviation is less than 2 ppmv in all cases.