ABSTRACT
The effects of CO2 ppm in troposphere on both spectral and total emissivity are
reviewed using several methods. The compared models are by Hottel [2], Bliss [3],
Atwater and Ball [4, 6], wide Band Model by Edwards [5], Yamamoto and Sasamori
[6,7], and using HITRAN data base [8]. For spectral emissivity, the results by
Yamamoto and Sasamori match well with predictions using HITRAN data base. For
total emissivity, the deviations between models are rather large and sometimes more
than about 0.05. In general, for a given condition, the upper bound of total emissivity
is given by Hottel, and lower bound is given by HITRAN. The predictions by Edwards
are in between but near to those of Hottel. The CO2 ppm varied from 300 ppm to
600 ppm, temperature varied from 220K to 300K, and pressure from 0.3 to 1.0atm.
As CO2 ppm increases, the total emissivity increases. For a given CO2 ppm, the total
emissivity increases as the air thickness increases which are also true for both
temperature and pressure increase. Around 260K, the total emissivity is less
sensitive to increasing temperature than to decreasing temperature. For a given
pressure change, the total emissivity values by wide band model changes more than
the values by HITRAN. The reverse is true for temperature change.