National Geographic : 1990 Apr
the possibility of landing wheeled transports able to carry bigger payloads on areas of rela tively smooth snow-free ice near the Pole. From there a tractor train would haul sup plies to the station. Test landings using lighter planes have already been made at a site 185 miles away. S MANY AS a hundred scientists and support workers occupy the South Pole station during summer months. During winter only 20 people inhabit the end of the earth. Among them was Betsy Crozer of Boulder, Colorado, who was operating the station's Clean Air Facility for the National Oceanic and Atmo spheric Administration. Its purpose: to moni tor the planet's air quality. "The South Pole has the cleanest air on earth," she told me. "Prevailing winds blow 98 percent of the time from the so-called Clean Air Sector-between 20 degrees west and 110 degrees east-and by the time air reaches us it is well mixed, and we're sure that we're not getting distorted measure ments caused by local sources of pollution." Air-quality monitoring has been going on since 1957 and has found constantly increas ing carbon dioxide levels. Recently, a new sophisticated laser device has been installed by the University of Rome to measure the height and thickness of polar stratospheric clouds, which form during winter darkness over Antarctica. In 1986 scientists discovered that molecules of chlorine compounds adhere to ice crystals in the clouds. This makes possible a catalytic reaction, triggered by the sun's first spring time rays, in which chlorine atoms destroy as much as half the ozone over Antarctica between September and November. Scientists believe most of the destructive chlorine comes from chlorofluorocarbons, or Peering from a catcher boat, Japanese crewmen watch for pods of minke whales, which can be legally taken only for research purposes. After a strike, blood stains the water as a whale is drawn in and secured (above right). While the boat moves amid floes of pancake ice (right), three freshly killed minkes await processing by a factory ship. Although the minke remains rela tively numerous, most whale species have been seriously depleted.