Aerosol characteristics and aerosol radiative forcing over Maitri, Antarctica
During the 20th Indian Antarctic expedition conducted in January-February 2001, a detailed study on the aerosol spectral optical depth, mass concentration and size-distribution along with columnar ozone and watervapour concentrations was made from the Indian station, Maitri (70.77° S, 11.73° E). A l...
| Main Authors: | , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
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Current Science Association
2004
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| Online Access: | http://repository.ias.ac.in/13416/ http://repository.ias.ac.in/13416/1/327.pdf http://www.ias.ac.in/currsci/jan252004/296.pdf |
| Summary: | During the 20th Indian Antarctic expedition conducted in January-February 2001, a detailed study on the aerosol spectral optical depth, mass concentration and size-distribution along with columnar ozone and watervapour concentrations was made from the Indian station, Maitri (70.77° S, 11.73° E). A low aerosol optical depth of about 0.03 at 400 nm wavelength and a dry aerosol mass concentration of about 7 µg/m 3 for the PM 10 particles are found for this anthropogenically least-affected continent on the earth. The aerosol sizedistribution reveals that about 63% of the total aerosol mass comes from particles of size greater than 1 µm, which are of mainly natural origin. Average columnar ozone and total precipitable water-vapour content during the observation period were found to be 271.6 DU and 0.147 cm respectively, and the observed day-to-day variations are explained using air back-trajectory analysis. Estimation of aerosol radiative forcing over Maitri reveals a positive forcing of 0.95 W/m 2 at the top of the atmosphere and -0.83 W/m 2 at the surface. Using model calculations, it is shown that these forcing values can have large annual variation both in magnitude and sign due to variation in the sun-earth geometry, typical of a polar region, even if we assume a constant aerosol amount throughout the year. |
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