Total ozone variability and change at southern mid-latitudes

FABIO E. MALANCA; GUSTAVO A. ARGÜELLO; PABLO O. CANZIANI

METEOROLOGICA

CENTRO ARGENTINO DE METEORÓLOGOS

Lugar: Buenos Aires; Año: 2003 vol. 28 p. 53 - 61

0325-187X

The variability of atmospheric mid-latitude ozone over the Southern Hemisphere is analyzed. The total ozone column distribution is discussed on the basis of TOMS data, binned at latitudes between 60º and 30º S. A strong longitudinal and latitudinal dependence of the seasonal and interannual variation of the ozone column was observed. The most severe depletions at mid-latitudes are located in the region between 80º W and 60º E, mainly over the South Atlantic. A change in the trends between the 80´s and 90´s is observed, such a change takes place prior to the maximum of stratospheric chlorine, which took place around 1997. The monthly trends show significant changes when data for the period 1979-2000 is compared with a similar analysis for the 80´s only. During the years sampled an eastward displacements of negative trends, between 30º and 60º in longitude can be observed in September and October. The location of this region shifts from west to east in spring, suggesting a seasonal shift of the polar vortex/ozone hole system. Such behavior probably implies a change in the seasonal evolution of the Antarctic dynamic processes.