Ozonesonde measurements at Syowa Station (69¿00'S, 39¿35'E) from 1971 to 1984 show that ozone depletion is most striking in the region 10km to 25km in the last five years. Active ozone loss region in the spring shows good correspondence to the region where noticeable drop in stratospheric temperature is observed from 1981 to 1985, but only in the spring.

Montly averaged lower-stratospheric temperature decreased smoothly during the period from about 1975 to the present in the spring. The temperatures in October and November of 1985 are comparable to the frost point temperature of water vapor with 10 ppmv mixing ratio at about 100mb. The temperature drops observed in interannual trends could activate formation of ice particles, and cause noticeable ozone loss in spring through heterogeneous ozone reduction reactions. ¿ American Geophysical Union 1987