Characteristics of aerosols over a remote island, Minicoy in the Arabian Sea: Optical properties and retrieved size characteristics
作者:
K. Krishna Moorthy,
S. K. Satheesh,
期刊:
Quarterly Journal of the Royal Meteorological Society
(WILEY Available online 2000)
卷期:
Volume 126,
issue 562
页码: 81-109
ISSN:0035-9009
年代: 2000
DOI:10.1002/qj.49712656205
出版商: John Wiley&Sons, Ltd
关键词: Aerosol characterization;Aerosol optical depth;Aerosol size distribution;Marine aerosols
数据来源: WILEY
摘要:
AbstractChanges in the characteristics of atmospheric aerosol over a marine environment are investigated by making regular spectral extinction measurements in the visible and near‐infrared region from a tiny island location. Minicoy (8.3°N, 73.04°E), situated in the Arabian Sea about 400 km due west of the southern tip of the Indian peninsula. The role of seasonally changing air‐mass type in causing a regular annual variation in the spectral optical depths is delineated. The association between aerosol optical depths, surface wind speed and rainfall is examined. An increase in wind speed causes an increase in optical depths, the effect is predominant when a marine air mass prevails. The impact of changes in wind speed on optical depths (due to sea‐spray production over the sea) is parametrized in the case that the island is influenced by a marine air mass. Columnar size distributions, retrieved from the spectral optical depths, in general, show a bimodal log‐normal distribution in the optically active size range. The accumulation mode is more sensitive to continental air‐mass types, while the coarse mode is influenced by the marine conditions. The coarse mode is sharper but its position is variable. Increase in wind speed leads to a remarkable enhancement in the concentration and relative abundance of coarse particles, particularly during the monsoon season. The mass loading and effective radius are well associated and depend on wind speed histories. The findings ar
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