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Main Title: On the climatic impact of CO2 ice particles in atmospheres of terrestrial exoplanets
Author(s): Kitzmann, Daniel
Patzer, A. B. C.
Rauer, Heike
Type: Article
Language Code: en
Abstract: Clouds play a significant role for the energy budget in planetary atmospheres. They can scatter incident stellar radiation back to space, effectively cooling the surface of terrestrial planets. On the other hand, they may contribute to the atmospheric greenhouse effect by trapping outgoing thermal radiation. For exoplanets near the outer boundary of the habitable zone, condensation of CO2 can occur due to the low atmospheric temperatures. These CO2 ice clouds may play an important role for the surface temperature and, therefore, for the question of habitability of those planets. However, the optical properties of CO2 ice crystals differ significantly from those of water droplets or water ice particles. Except for a small number of strong absorption bands, they are almost transparent with respect to absorption. Instead, they are highly effective scatterers at long and short wavelengths. Therefore, the climatic effect of a CO2 ice cloud will depend on how much incident stellar radiation is scattered to space in comparison to the amount of thermal radiation scattered back towards the planetary surface. This contribution aims at the potential greenhouse effect of CO2 ice particles. Their scattering and absorption properties are calculated for assumed particle size distributions with different effective radii and particle densities. An accurate radiative transfer model is used to determine the atmospheric radiation field affected by such CO2 particles. These results are compared to less detailed radiative transfer schemes employed in previous studies.
Issue Date: 2012
Date Available: 27-Nov-2017
DDC Class: 520 Astronomie und zugeordnete Wissenschaften
526 Mathematische Geografie
Subject(s): planets and satellites
radiative transfer
Journal Title: Proceedings of the International Astronomical Union
Publisher: Cambridge University Press
Publisher Place: Cambridge
Volume: 8
Issue: S293
Publisher DOI: 10.1017/s1743921313013045
Page Start: 303
Page End: 308
EISSN: 1743-9221
ISSN: 1743-9213
Notes: Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
Appears in Collections:Zentrum für Astronomie und Astrophysik » Publications

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