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: Moorthy, Krishna K, Satheesh, SK, Babu, Suresh S, Saha, Auromee
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union 2005
• Subjects: Centre for Atmospheric & Oceanic Sciences; Indian; Southern Ocean
• Online Access: http://eprints.iisc.ac.in/27565/; 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 MB remains extremely low(<50 ng m(-3)) and remarkably steady (in space and time) in the Southern Ocean (20 degrees S to 56 degrees S). In contrast, large latitudinal gradients exist north of similar to 20 degrees S; M-B increasing exponentially to reach as high as 2000 ng m(-3) in the Arabian Sea (similar to 8 degrees 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.