NORTHERN-HEMISPHERE TOTAL OZONE VALUES FROM 1989-1993 DETERMINED WITHTHE NOAA-11 SOLAR BACKSCATTER ULTRAVIOLET (SBUV 2) INSTRUMENT/

Determinations of global total ozone amounts have been made from recen tly reprocessed measurements with the SBUV/2 on the NOAA-11 environmen tal satellite since January 1989. This data set employs a new algorith m and an updated calibration. Comparisons with total ozone amounts der ived from a significant subset of the global network of Dobson spectro photometers shows a 0.3% bias between the satellite and ground measure ments for the period January 1989-May 1993. Comparisons with the data from individual stations exhibit differing degrees of agreement which could be due to the matchup procedures and also to the uncertainties i n the Dobson data. The SBUV/2 data set discussed here traces the North ern Hemisphere total ozone from 1989 to the present, showing a marked decrease from the average of those years starting in the summer of 199 2 and continuing into 1993, with an apparent returning to more normal levels in late 1993.