عنوان مقاله [English]
نویسنده [English]چکیده [English]
In order to recognize and understand the mechanism governing on variations and
decrease of stratospheric ozone, the dynamical characteristics of Middle atmosphere
specially,atmospheric circulation and mass transport in the stratosphere were
The first, characteristics of stratospheric ozone such as it’s production and
temporal and spatial distribution of it has been noticed. Then, considering the very
important role of stratospheric circulation in distribution, variation and decrease of
stratospheric ozone, with presentation of a division of stratospheric circulation; mean
characteristics of zonal(consist of Polar Vortex, Surf Zone, QBO and summer
hemisphere circulation) and meridional circulation(Brewer-Dobson circulation) has
In following, in order to explanation of stratospheric ozone depletion, trend of
temporal and spatial ozone decreasing were investigated. Finally, links between the
most important dynamical components, i.e. Polar Vortex, Planetary Scale Rossby
Waves, Stratospheric Sudden Warming, QBO and variations and depletion of
stratospheric ozone, illustrated.
The results indicate that since 1980, the global mean of ozone decrease was about
3% and the largest decreases have been observed over the polar regions of two
hemispheres in spring.
Stratospheric Polar Vortex has a key role in interannual variability of Total Ozone
and account a necessary precondition for ozone depletion and formation of
stratospheric ozone hole. Therefore, Shape, Area, intensity and Persistence of Polar
Vortex in two hemisphere is determining ozone decrease rate and the maximum areal
coverage of ozone hole.
Dynamical forcing from troposphere is the major source of stratospheric variations
and upward propagation of planetary waves in addition to the occurance Brewer-
Dobson circulation and Stratospheric Sudden Warming, is controlling the temporal and
spatial distribution of total ozone and decrease and increase of stratospheric ozone.
Hence, the circulation of the winter stratosphere is strongly influenced by vertically
propagating forced planetary waves and rate of planetary waves activity in stratosphere
and their interaction with dynamical components such as QBO and Polar Vortex,
additionally control of Brewer-Dobson circulation and temperature ratio, is
determining transport and interannual variability of stratospheric ozone.