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| Titel |
Effect of the summer monsoon on aerosols at two measurement stations in Northern India – Part 2: Physical and optical properties |
| VerfasserIn |
A.-P. Hyvärinen, T. Raatikainen, M. Komppula, T. Mielonen, A.-M. Sundström, D. Brus, T. S. Panwar, R. K. Hooda, V. P. Sharma, G. Leeuw, H. Lihavainen |
| 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. 16 ; Nr. 11, no. 16 (2011-08-15), S.8283-8294 |
| Datensatznummer |
250010004
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| Publikation (Nr.) |
 copernicus.org/acp-11-8283-2011.pdf |
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| Zusammenfassung |
| Aerosol physical and optical properties were measured at two locations in
northern India. The first measurement station was a background site in
Mukteshwar, about 350 km northeast of New Delhi, in the foothills of the
Indian Himalayas, with data from 2006 to 2009. The second measurement site
was located in Gual Pahari, about 25 km south of New Delhi, with data from
2008 to 2009. At both stations, the average aerosol concentrations during
the monsoon were decreased by 40–75 % compared to the pre-monsoon average
concentrations. The decrease varied with the total local rainfall. In
Mukteshwar, the monsoon season removed particles from all size classes, due
to a combination of rain scavenging and activation to cloud and mountain
fog droplets. The scavenging by rain is least effective for the size range
of the accumulation mode particles. In Gual Pahari, this was the only major
wet removal mechanism and, as a result, the accumulation mode particles were
less effectively removed. Aerosol concentrations during the early monsoon
were found to be affected by mineral dust which in Gual Pahari was observed
as an increased particle volume at a diameter around 3–4 μm. The single
scattering albedo varied from 0.73 to 0.93 during the monsoon season, being
slightly lower in Gual Pahari than in Mukteshwar. This is due to the fact
that Gual Pahari resided closer to high anthropogenic black carbon
emissions. As the absorbing particles are typically in the accumulation
mode, they were not effectively removed by rain scavenging. The aerosol
columnar properties, which were measured in Gual Pahari, showed a somewhat
different seasonal behaviour compared to the surface measurements, with the
aerosol optical depth increasing to an annual maximum in the early monsoon
season. |
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