  Carbon Dioxide (CO2) is one of the most important greenhouse gases after
water vapor (H2O) which plays significant role in the climate process. Accurate
space-based measurement of CO2 is of great significance in inferring the
location of CO2 sources and sinks. Uncertainties in greenhouse gases (GHG)
retrieval process must be minimized to accurately infer the actual amount of
the atmospheric species. Clouds pose a large uncertainty in CO2 space-based
retrieval process leading, mostly, to an underestimation in the CO2 absorption
amount above the cloud layer provided that photons do not perform multiple
paths. In this paper, three different cases of data collected over cloudy and
clear skies by Argus 1000 micro-spectrometer were analyzed. Findings show that
the CO2 absorption in the absence of clouds is approximately 4.5% higher than
when clouds are present.
