A GLOBAL BLACK CARBON AEROSOL MODEL

A global inventory has been constructed for emissions of black carbon from fossil fuel combustion and biomass burning. This inventory has be en implemented in a three-dimensional global transport model and run f or 31 model months. Results for January and July have been compared wi th measurements taken from the literature, The modeled values of black carbon mass concentration compare within a factor of 2 in continental regions and some remote regions but are higher than measured values i n other remote marine regions and in the upper troposphere, The disagr eement in remote regions can be explained by the coarse grid scale of the model (10 degrees x 10 degrees), the simplicity of the current dep osition scheme, and possibly too much black carbon being available for transport, which would also account for the disagreement in the upper troposphere. The disagreement may also be due to problems associated with the measurement of black carbon. Emissions from this database app ear to provide a reasonable estimate of the annual emissions of black carbon to the atmosphere. Biomass burning emissions amount to 5.98 Tg and that from fossil fuel amounts to 7.96 Tg. A local sensitivity anal ysis has been carried out and shows that black carbon has a lifetime b etween 6 and 10 days, depending on the transformation rate between hyd rophobic and hydrophilic black carbon.