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Titel |
Deep convective clouds at the tropopause |
VerfasserIn |
H. H. Aumann, S. G. DeSouza-Machado, A. Behrangi |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 3 ; Nr. 11, no. 3 (2011-02-11), S.1167-1176 |
Datensatznummer |
250009299
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Publikation (Nr.) |
copernicus.org/acp-11-1167-2011.pdf |
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Zusammenfassung |
Data from the Atmospheric Infrared Sounder (AIRS) on the EOS Aqua spacecraft
each day show tens of thousands of Cold Clouds (CC) in the tropical oceans
with 10 μm window channel brightness temperatures colder than 225 K.
These clouds represent a mix of cold anvil clouds and Deep Convective Clouds
(DCC). This mix can be separated by computing the difference between two
channels, a window channel and a channel with strong CO2 absorption:
for some cold clouds this difference is negative, i.e. the spectra for some
cold clouds are inverted. We refer to cold clouds with spectra which are
more than 2 K inverted as DCCi2. Associated with DCCi2 is a very high rain
rate and a local upward displacement of the tropopause, a cold "bulge",
which can be seen directly in the brightness temperatures of AIRS and
Advanced Microwave Sounding Unit (AMSU) temperature sounding channels in the
lower stratosphere. The very high rain rate and the local distortion of the
tropopause indicate that DCCi2 objects are associated with severe storms.
Significant long-term trends in the statistical properties of DCCi2 could be
interesting indicators of climate change. While the analysis of the nature
and physical conditions related to DCCi2 requires hyperspectral infrared and
microwave data, the identification of DCCi2 requires only one good window
channel and one strong CO2 sounding channel. This suggests that
improved identification of severe storms with future advanced geostationary
satellites could be accomplished with the addition of one or two narrow band
channels. |
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