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| Titel |
Aerosol and rainfall variability over the Indian monsoon region: distributions, trends and coupling |
| VerfasserIn |
R. Gautam, N. C. Hsu, K.-M. Lau, M. Kafatos |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 27, no. 9 ; Nr. 27, no. 9 (2009-09-30), S.3691-3703 |
| Datensatznummer |
250016661
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| Publikation (Nr.) |
 copernicus.org/angeo-27-3691-2009.pdf |
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| Zusammenfassung |
| Aerosol solar absorption over the Indian monsoon region has a potential role
of modulating the monsoon circulation and rainfall distribution as suggested
by recent studies based on model simulations. Prior to the onset of the
monsoon, northern India is influenced by significant dust transport that
constitutes the bulk of the regional aerosol loading over the
Gangetic-Himalayan region. In this paper, a multi-sensor characterization of
the increasing pre-monsoon aerosol loading over northern India, in terms of
their spatial, temporal and vertical distribution is presented. Aerosol
transport from the northwestern arid regions into the Indo-Gangetic Plains
and over the foothills of the Himalayas is found to be vertically extended
to elevated altitudes (up to 5 km) as observed from the space-borne lidar
measurements (CALIPSO). In relation with the enhanced pre-monsoon aerosol
loading and the associated solar absorption effects on tropospheric
temperature anomalies, this paper investigates the monsoon rainfall
variability over India in recent past decades from an observational
viewpoint. It is found that the early summer monsoon rainfall over India is
on the rise since 1950s, as indicated by historical rainfall data, with over
20% increase for the period 1950–2004. This large sustained increase in
the early summer rainfall is led by the observed strengthening of the
pre-monsoon tropospheric land-sea thermal gradient over the Indian monsoon
region as indicated by microwave satellite measurements (MSU) of
tropospheric temperatures from 1979–2007. Combined analysis of changes in
tropospheric temperatures and summer monsoon rainfall in the past three
decades, suggest a future possibility of an emerging rainfall pattern of a
wetter monsoon over South Asia in early summer followed by a drier period. |
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