Abstract:
We present an analysis of the carbon, potassium and sulfate content of the extensive aerosol haze layer observed over the tropical Indian Ocean during the Indian Ocean Experiment (INDOEX). The black carbon (BC) content of the haze is as high as 17% of the total fine particle mass (the sum of carbonaceous and soluble ionic aerosol components) which results in significant solar absorption. The ratio of black carbon to organic carbon (OC) lover the Arabian Sea and equatorial Indian Ocean) was a factor of 5 to 10 times larger than expected for biomass burning. This ratio was closer to values measured downwind of industrialized regions in Japan and Western Europe. These results indicate that fossil fuel combustion is the major source of carbonaceous aerosols, including black carbon during the events considered. If the data set analyzed here is representative of the entire INDOEX study then fossil fuel emissions from South Asia must have similarly contributed to aerosols over the whole study region. The INDOEX ratios are substantially different from those reported for some source regions of South Asia, thus raising the possibility that changes in composition of carbonaceous aerosol may occur during transport.

KeyWords Plus:
PRE-INDOEX CRUISE, ATMOSPHERIC AEROSOL, URBAN, PARTICLES, HYDROCARBONS, EMISSIONS, SAPPORO, JAPAN, SIZE, ASIA

Addresses:
Novakov T, Lawrence Berkeley Lab, Environm Energy Technol Div, MS-73,1 Cyclotron Rd, Berkeley, CA 94720 USA
Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA
Max Planck Inst Chem, Biogeochem Dept, D-55020 Mainz, Germany
Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA

Publisher:
AMER GEOPHYSICAL UNION, 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA

IDS Number:
390TB

ISSN:
0094-8276