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| Titel |
Investigation of negative cloud radiative forcing over the Indian subcontinent and adjacent oceans during the summer monsoon season |
| VerfasserIn |
B. V. Thampi, R. Roca |
| 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 ; 14, no. 13 ; Nr. 14, no. 13 (2014-07-03), S.6739-6758 |
| Datensatznummer |
250118860
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| Publikation (Nr.) |
 copernicus.org/acp-14-6739-2014.pdf |
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| Zusammenfassung |
| Radiative properties of clouds over the Indian subcontinent and nearby
oceanic regions (0–25° N, 60–100° E) during the Asian
summer monsoon season (June–September) are investigated using the Clouds and
Earth's Radiant Energy System (CERES) top-of-the-atmosphere (TOA) flux data.
Using multiyear satellite data, the net cloud radiative forcing (NETCRF) at
the TOA over the Indian region during the Asian monsoon season is examined.
The seasonal mean NETCRF is found to be negative (with its magnitude
exceeding ~30 Wm−2) over (1) the northern Bay of Bengal
(close to the Myanmar–Thailand coast), (2) the Western Ghats and (3) the
coastal regions of Myanmar. Such strong negative NETCRF values observed over
the Indian monsoon region contradict the assumption that near cancellation
between LWCRF and SWCRF is a generic property of all tropical convective
regions. The seasonal mean cloud amount (high and upper middle) and
corresponding cloud optical depth observed over the three regions show
relatively large values compared to the rest of the Indian monsoon region. Using
satellite-derived cloud data, a statistical cloud vertical model delineating
the cloud cover and single-scattering albedo was developed for the three
negative NETCRF regions. The shortwave (SW), longwave (LW) and net cloud
radiative forcing over the three negative NETCRF regions are calculated
using the rapid radiative transfer model (RRTM) with the cloud vertical model as
input. The NETCRF estimated from CERES observations show good comparison
with that computed using RRTM (within the uncertainty limit of CERES
observations). Sensitivity tests are conducted using RRTM to identify the
parameters that control the negative NETCRF observed over these regions
during the summer monsoon season. Increase in atmospheric water vapor
content during the summer monsoon season is found to influence the negative
NETCRF values observed over the region. |
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