Multiple cirrus analysis models are useful for verifying independently derived cirrus characteristics within the same cloud scene. The CO₂ technique retrieves effective emissivity Ne, the product of cloud fraction "N" and emissivity "e," and is capable of detecting thin cirrus at levels where the carbon-dioxide weighting functions peak. For each relatively coarse sounder field of view a cirrus cloud fraction estimate "N" can be made from the imager data using a multispectral cloud mask. The sounder emissivity e can then be decoupled from the effective emissivity Ne by dividing by N. This in turn allows for direct comparison between the imager and sounder emissivity retrievals for those cloudy pixels that lie within the sounder pixel.

Additionally, comparisons will be made between the summary statistics of both retrievals for a time series of data over the northeast US and adjacent Atlantic Ocean. Frequency distributions of cloud-top temperature (height, pressure) and optical thickness will be made for the sounder and TIR retrievals, and plots of emissivity versus cloud-top height will also be made in order to investigate whether there is a dependence between cloud temperature and cloud optical properties. These results will provide a valuable comparison between CO₂ Slicing, for which long-term cloud climatologies exist, and an independent but coterminous TIR imager cloud analysis.