Ozone and c2-c5 hydrocarbon observations in the marine boundary layer between 45°S and 77°S

During the austral summer of 1993, measurements of surface ozone (O3), nonmethane hydrocarbons (NMHC), lead-212 and radon-222 activity were performed on board the vessel ANTARCTICA between 43°S and 77°S. The latitudinal variations of light C2–C5 alkanes reflect the relatively short photochemical lifetime of these compounds and their intensive photochemical destruction during summer. Average mixing ratios of ethane, propane and acetylene were 291 ± 76 pptv, 61 ± 53 pptv and 48 ± 35 pptv, respectively, in good agreement with published measurements previously undertaken in the Antarctic region. O3 mixing ratios ranged from 8.5 ppbv to 22.2 ppbv. The few relatively high values of ozone that have been observed during EREBUS94 campaign occurred simultaneously with high Rn-222 activities and possibly indicated continental influence through transport of air masses in the free troposphere. With the exception of these high O3events, the O3 and NMHC observations, in conjunction with air mass back trajectory analysis, radon-222 observations and a global 3-D model calculations, suggest that the troposphere/stratosphere exchanges play an important role on ozone budget at the high latitudes of the southern hemisphere.DOI: 10.1034/j.1600-0889.1998.t01-4-00003.x