Ozone enhanced layers in the 2003 Antarctic ozone hole

Abstract

Ozone enhanced layers observed inside the Antarctic ozone hole were investigated using ozonesonde data at Syowa and Neumayer Stations during the dissipation period of the ozone hole in 2003. In 22 ozonesonde observations performed at Syowa and Neumayer Stations during one month after the maximum of ozone hole area, 17 ozone enhanced layers (i.e., up to three layers per one observation) were detected between 14 and 21 km in the lower stratosphere. They always had a thickness thinner than 2.1 km. Maximum ozone mixing ratios in the ozone enhanced layers suggested that most of the layers had their origin in the vortex boundary region. A reverse domain filling analysis indicated that air parcels originating in the vortex boundary region reached Syowa and Neumayer Stations in a form of horizontally-thin filaments. These filamentary structures were generated through chaotic advection due to transient planetary-scale Rossby waves, and became thin also in the vertical because of the vertical shear of horizontal wind. This study suggests that the ozone enhanced layers inside the ozone hole could be a useful measure to identify the poleward Rossby wave breaking and the origin of transported air parcels. A contribution of the ozone enhanced layers to an increase of total ozone was estimated at about 2.1 DU for the analysis period of one month, which is less than one tenth of the increase of vortex average total ozone during the same period. On the other hand, it is corresponding to about a half of the background ozone column in the height region of 14-21 km at the time of the ozone hole area maximum. © 2010, Meteorological Society of Japan.