OZONE CHANGE FROM 1992 TO 1993 AS OBSERVED FROM SSBUV ON THE ATLAS-1 AND ATLAS-2 MISSIONS

The Shuttle SBUV (SSBUV) conducted its fourth and fifth flights in lat e March 1992 and early April 1993 along with the ATLAS-1 and ATLAS-2 S huttle missions, respectively. The two successive SSBUV flights yielde d ozone data nearly one year apart. An analysis of the meteorological conditions, namely temperature and winds, during the two flight period s indicate that the conditions in the stratosphere were very similar. The temperatures had significantly warmed from winter throughout most of the stratosphere and the circulation was approaching normal summert ime conditions for both periods. SSBUV-4, flown in 1992, measured ozon e from approximately 30S to 60N while SSBUV-5, flown in 1993, measured ozone from approximately 55S to 60N. Zonal average column ozone amoun ts were derived from the two flights and compared to determine if a sy stematic change in ozone could be detected despite the fact that only a few days from each year were sampled. The comparison indicates that in the latitude range 30N to 60N total ozone was lower in 1993 than in 1992 by about 12%. This change is larger than the observational error s and the expected interannual variations. This result verifies simila r data taken from ground and satellites.