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Ozone variation during a case of cyclogenesis

H. Abdel Basset, A. Badawi, M. Eid

Abstract

The relationship between total column ozone (TCO) and the development of a cyclonic system that occurred in the period from January 18 to January 25, 1981 has been studied using the ERA-Interim reanalysis database. It was found that TCO increases and decreases with the development and weakening of the cyclonic system. Also, a good correlation between TCO and the thickness of the layer was found between 1000-100 hPa and tropopause pressure. The study of daily variations in TCO based on the vertical distribution of the ozone mass mixing ratio (OMR) illustrate that with the beginning of the growth period there is a high decrease of the tropopause height, which was associated to high deepening of the cyclone and was accompanied by a significant vertical increase of OMR in the troposphere and stratosphere. The obvious significant increase of OMR starts at the stratospheric layer and is then transported to the tropospheric layer. The analysis of the time-height variation of the differences of OMR between the average of the domain containing the center of the cyclone at each level and the corresponding monthly average, illustrates that during the days of maximum deepening the positive values of OMR extend downwards to reach the 850 hPa level. The increase in positive values continues to be higher in the upper levels and reaches maximum values between 300-100 hPa and also between the 60-10 hPa layer. The characteristics of these changes of OMR concentrations from layer to layer are predominantly due to dynamical processes. Also, this was attributed to the effect of horizontal advection of ozone from a different neighboring region into the column, and by a vertical exchange of air between the high ozone at the stratosphere and low ozone at troposphere.

Keywords

total column ozone; cyclone; cyclogenesis; tropopause pressure; atmospheric thickness; stratosphere; troposphere; ozone mixing ratio

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