Global average ozone change from November 1978 to May 1990

Abstract

A recent recalibration and reprocessing of the total ozone mapping spectrometer (TOMS) data have made possible a new determination of the global average (69°S to 69°N) total ozone decrease of 3.5% over the 11‐year period, January 1, 1979, to December 31, 1989, with a 2σ error of 1.4%. The revised TOMS ozone trend data are in agreement, within error limits, with the average of 39 ground‐based Dobson stations and with the world standard Dobson spectrometer 83 at Mauna Loa, Hawaii. Superimposed on the 11‐year ozone trend is a possible solar cycle effect, quasi‐biennial oscillation (QBO), annual, and semiannual cycles. Using solar 10.7‐cm flux data and 30‐mbar Singapore wind data (QBO), a time series has been constructed that reproduces the long‐term behavior of the globally averaged ozone. Removal of the apparent solar cycle effect from the global average reduces the net ozone loss to 2.66±1.4% per decade. The precise value of the global average ozone trend depends on the latitude range selected, with ranges greater than ±69° emphasizing the larger variations at high latitudes.