AEROSOL BLACK CARBON MEASUREMENTS OVER THE WESTERN ATLANTIC OCEAN

During the aircraft operations phase of the Western Atlantic Ocean Experiment (WATOX) program conducted in January 1986 off the eastern seaboard of the United States, we performed measurements of the optically absorbing carbonaceous component of the ambient aerosol. We collected the aerosol on filters that were exposed for several hours; we also operated the aethalometer to measure the concentration of aerosol black carbon in real time. The filter analyses represent averages over the altitude range and time span during which the filter was collecting. The real-time results were sorted by altitude to calculate vertical profiles of black carbon concentration. Values typically ranged from 200 to 500 ng/m(3) in the boundary layer, decreasing to 50 to 100ng/m(3) at higher altitudes. By multiplying the mean concentration profile by the offshore air flux, we may estimate the export of aerosol black carbon from the coast to be of the order of 5 x 10(10) g/yr.