HYDROGEN AND CARBON-MONOXIDE AT TERRA-NOVA BAY (ANTARCTICA)

During the 1990-91 austral summer atmospheric hydrogen and carbon monoxide were measured on the spot and continuously during one month, near the Terra Nova Italian base in Antarctica. The present work represents the continuation of the previous campaign; the 1990-91 results (H2 = 522 +/- 1 ppbv and CO = 51 +/- 1 ppbv) indicate concentrations similar to the ones found in the 1989-90 summer for both components. The sudden hydrogen peaks found in 1989-90 were not found again in 1990-91, confirming the hypothesis that they were local artifacts. CO shows some slow variations as well as a sharp peak (pollution?); yet the concentration dependence on the wind direction (origin of air masses) is not so evident as in 1989-90. The former component represents an even worldwide distribution, while CO represents the present base level for the whole atmosphere. as can be found only in the most remote areas like the southern oceans and Antarctica; this is a consequence of its short residence time in the atmosphere.