Trends in Dobson total ozone: An update through 1983

We estimate the trends in Dobson total ozone records from 1970 through 1983, using ozone data from 1964 through 1983. These estimates range from −0.31%/decade ± 0.49%/decade (1σ) for unadjusted data to −1.10%/decade ± 0.47%/decade for data adjusted for instrument interventions and the solar cycle. The negative trends are primarily the result of abnormally low total ozone values in the northern hemisphere during early 1983.