Dependence of ozone and other minor species response to annual and interannual variability of atmospheric parameters over Antarctica

Abstract A role of specific atmospheric condition (low air pressure) over South Pole for stratospheric gas-phase photochemistry has been investigated on the basis of data analysis and photochemical numerical modeling. There were no heterogeneous reactions which were used in calculations to estimate a pure effect of gas phase chemistry and photolysis rates on ozone in presence of air depression. The results of model runs have shown a strong correlation between air pressure deficit over South polar region and column ozone. The behavior of ozone content after sunrise in Antarctica, in accordance with calculations, has a visible cavity with time and looks like “ozone hole”. The maximum of calculated ozone depletion was placed above 20 km level (in contrast to the observations) in presence of negligible vertical transport caused by eddy diffusion, but when diffusion was took into account the results were more similar to observations. Correspondent rapid ozone depletion after sunrise may equal about 100 DU in presence of vertical eddy diffusion. So, some rather rapid solutions are possible to find inside gas-phase stratospheric photochemical system if real annual cycle and interannual variability in pressure are taken into account. Strong enhancement of ClO content after sunrise has been found also in calculations around 20 km level. This effect was initiated by increased photolysis rates. A physical explanation of the described effects is based on strong dependence of ozone destruction on the air density and its non-linear character which leads to a very short time of ozone relaxation after sunrise over South Pole. However, it is necessary to mention that the model does not include heterogeneous chemistry and that it is 1-D model, i.e. the model cannot include transport, which plays an important role in the South Pole region.