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| Titel |
Systematic variations of cloud top temperature and precipitation rate with aerosols over the global tropics |
| VerfasserIn |
Feng Niu, Zhanqing Li |
| 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 ; 12, no. 18 ; Nr. 12, no. 18 (2012-09-21), S.8491-8498 |
| Datensatznummer |
250011459
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| Publikation (Nr.) |
 copernicus.org/acp-12-8491-2012.pdf |
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| Zusammenfassung |
| Aerosols may modify cloud properties and precipitation via a variety of
mechanisms with varying and contradicting consequences. Using a large
ensemble of satellite data acquired by the Moderate Resolution Imaging
Spectroradiometer onboard the Earth Observing System's Aqua platform, the
CloudSat cloud profiling radar and the Cloud-Aerosol Lidar and Infrared
Pathfinder Satellite Observations (CALIPSO) satellite over the tropical
oceans, we identified two distinct correlations of clouds and precipitation
with aerosol loading. Cloud-top temperatures are significantly negatively
correlated with increasing aerosol index (AI) over oceans and aerosol
optical depth (AOT) over land for deep mixed-phase clouds with liquid
droplets near the warm bases and ice crystals near the cold tops; no
significant changes were found for uniformly liquid clouds. Precipitation
rates are positively correlated with the AI for mixed-phase clouds, but
negatively correlated for liquid clouds. These distinct correlations might
be a manifestation of two potential mechanisms: the invigoration effect
(which enhances convection and precipitation) and the microphysical effect
(which suppresses precipitation). We note that the highly limited
information garnered from satellite products cannot unequivocally support
the causal relationships between cloud-top temperature/precipitation rate
and aerosol loading. But if aerosols are indeed the causes for the observed
relationships, they may change the overall distribution of precipitation,
leading to a more extreme and unfavorable rainfall pattern of suppressing
light rains and fostering heavy rains. |
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