Vertical sensitivity of satellite remote sensing of atmospheric carbon monoxide

The vertical sensitivity of the new MOPITT version 5 (V5) data is examined in terms of the averaging kernels and the Degree of Freedom of Signals (DFS). The MOPITT´s vertical sensitivity is enhanced in V5 NIR/TIR data, noticeably with elevated averaging kernels in the free troposphere, in addition to in the lower troposphere emphasized previously. DFS is most enhanced over land in the Northern Hemispheric middle to high latitudes (up to 1.5). DFS is higher in winter and spring than in summer and autumn, higher over land than over the oceans, higher in the tropics than in the high latitudes. Globally, the mean maximum DFS can reach 2.5, while individual profiles can contain over 2.5 pieces of independent information vertically. Although with limited vertical sensitivity, MOPIIT CO data can generally distinguish CO in the lower, middle, and upper troposphere, thus are useful in addressing scientific questions related to air quality and climate change.