Large latitudinal gradients and temporal heterogeneity in aerosol black carbon and its mass mixing ratio over southern and northern oceans observed during a trans-continental cruise experiment

• Main Authors: Krishna Moorthy, K., Satheesh, S. K., Babu, S. Suresh, Saha, Auromeet
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union 2005
• Subjects: Indian; Southern Ocean
• Online Access: http://repository.ias.ac.in/17147/; http://repository.ias.ac.in/17147/1/340.pdf; http://www.agu.org/pubs/crossref/2005./2005GL023267.shtml

Extensive, and collocated measurements of the mass concentrations (M B ) of aerosol black carbon (BC) and (M T ) of composite aerosols were made over the Arabian Sea, tropical Indian Ocean and the Southern Ocean during a trans-continental cruise experiment. Our investigations show that M B remains extremely low (<50 ng m -3 ) and remarkably steady (in space and time) in the Southern Ocean (20°S to 56°S). In contrast, large latitudinal gradients exist north of ~20°S; M B increasing exponentially to reach as high as 2000 ng m -3 in the Arabian Sea (~8°N). Interestingly, the share of BC showed a distinctly different latitudinal variation, with a peak close to the equator and decreasing on either side. Large fluctuations were seen in M T over Southern Ocean associated with enhanced production of sea-salt aerosols in response to sea-surface wind speed. These spatio-temporal changes in M B and its mixing ratio have important implications to regional and global climate.