Vernal Atmospheric Mixing in the Antarctic

Abstract

Aerosol concentration, ozone concentration, and meteorological parameters were measured at McMurdo and South Pole stations during a spring storm that reached the Antarctic interior. Nacreous clouds were sighted preceding the storm indicative of stratospheric flow from lower latitudes. These measurements and observations, along with upper-air and surface analyses indicate that vigorous tropospheric/stratospheric exchange of air occurs near 75°S during the spring. The elemental composition of collected aerosol changed coincidently with different stages of the storm. During the storm event in September 1983, surface ozone concentration varied from 20 to more than 100 ppbv at McMurdo, but remained less than 20 ppbv at the South Pole indicating that deep mixing, which occurred at the periphery of Antarctica during the spring storm, did not continue over the interior of the continent. The warm marine air associated with the spring coastal storm infiltrated the interior of Antarctica including the Polar Plateau, producing a record surface temperature and an aerosol concentration twice the September mean. This system was unusual as the warm front apparently reached the surface of South Pole. Crustal material was transported to the periphery of Antarctica through the upper troposphere or lower stratosphere. Enhanced aerosol concentration was transported to the South Pole through the lower troposphere. Vigorous exchange occurred at latitudes of greater than 78°S, which probably exchanged both marine aerosol and water vapor into the lower stratosphere.