Seasonal variation of the aerosol light scattering coefficient in marine air of the northeast atlantic
Vaishya, Aditya Jennings, S. G. O'Dowd, Colin
Vaishya, Aditya
Jennings, S. G.
O'Dowd, Colin
Publication Date
2011-01-01
Type
Article
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Citation
Vaishya, Aditya; Jennings, S. G. O'Dowd, Colin (2011). Seasonal variation of the aerosol light scattering coefficient in marine air of the northeast atlantic. Advances in Meteorology ,
Abstract
Aerosol light scattering measurements were carried out using a TSI 3563 Nephelometer at the Mace Head Atmospheric Research Station, on the west coast of Ireland from year 2001-2010. A strong seasonal trend in the aerosol light scattering coefficient at 550nm (sigma(cat)), for clean marine air masses, is observed with a high sigma(cat) value, [average (geometric mean)] of 35.3Mm(-1) (29.5Mm(-1)), in January and a low sigma(cat) value of 13.7Mm(-1) (10.2Mm(-1)), in July. This near threefold increase in the sigma(cat) value during the winter season is because of the large contribution of wind-speed generated sea-salt particles in the marine boundary layer. A high positive correlation coefficient of 0.82 was found between the percentage occurrence of relatively large angstrom ngstrom exponent (angstrom) values (> 1.2) and the percentage occurrence of lower sigma(cat) values (5-15Mm(-1)) in the summer season. sigma(cat) and wind-speed have a high positive correlation coefficient of 0.88 whereas angstrom and wind-speed have a negative correlation coefficient of -0.89. angstrom values during the summer months indicate the dominance of sub-mu m particles thus indicating the contribution of non-sea-salt sulphate and organics towards the sigma(cat) as these species show an enhanced concentration during the summer months.
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Publisher
Hindawi Limited
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Attribution-NonCommercial-NoDerivs 3.0 Ireland