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| Titel |
Classifying ice water content profiles of high-level clouds from AIRS/CALIPSO/CloudSat observations to better assess cloud radiative effects |
| VerfasserIn |
Artem Feofilov, Claudia Stubenrauch, Raymond Armante |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077672
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| Zusammenfassung |
| About 40% of all clouds on Earth are high-level clouds (< 440 hPa), which have a noticeable
effect on the energetic budget of the atmosphere: optically thick clouds reflect the incoming
solar radiation while thinner clouds act as “greenhouse films” preventing escape of the
Earth’s infrared radiation to space. Accurate modelling of the radiative properties of
high-level clouds is essential both for estimating their energetic effects and for the retrieval of
bulk microphysical properties from infrared observations. It requires knowing the
scattering and absorbing characteristics of cloud particles, amount of ice in the
cloud, and variation of these parameters if the cloud is extended. In this work, we
concentrate on vertical distribution of ice water content (IWC) in the high-level ice
clouds.
For the analysis, we used a synergy of the active and passive sounders of the A-Train satellite
constellation. Relatively high spectral resolution of the Atmospheric InfraRed Sounder
(AIRS) allows the identification of cirrus clouds and the retrieval of their physical and bulk
microphysical properties as well as their horizontal extent. Active sounders, the CALIPSO
lidar and the CloudSat radar, provide the vertical structure of the clouds: the radar-lidar
GEOPROF dataset (Mace et al., 2007) contains the vertical extent and position of each cloud
layer while the liDARraDAR dataset (Delanoë and Hogan, 2010) gives the IWC profiles and
effective ice crystal sizes. In addition, we use environmental parameters from ERA Interim
reanalyses.
We have classified IWC vertical distributions according to their profile shape and found that
a) they can be sub-divided into four major types; b) profile shape mainly depends on the
integrated IWC of the cloud; c) there is a weak correlation between vertical wind and
dominating profile type. We discuss an impact of different IWC profile types on
the energetics of the atmosphere and on bulk microphysical properties retrieval,
using the calculations performed with the 4A/OP+DISORT radiative transfer code
(http://4aop.noveltis.com/). Obtained statistics on IWC profile types can be used for
validation of the models.
References
Delanoë, J., and R. J. Hogan, J. Geophys. Res., 115(D00H29), doi:10.1029/2009JD012346,
2010
Mace, G. G., et al., Geophys. Res. Lett., 34, L09808, doi:10.1029/2006GL029017,
2007 |
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