Download Meteorology of the stratosphere - University of Reading, Meteorology

1st SPARC / Stratospheric Network for the Assessment of Predictability (SNAP) Workshop,
24-26 April 2013, Reading, England, UK
Meteorology of the stratosphere
Younis AL-Fenadi
Libyan National Meteorological Centre (LNMC)
Tripoli – Libya
[email protected]
I. Objective
The stratosphere is one of the five Earth’s atmosphere layers. It has received
little attention till the early eighties when the chlorofluorocarbons (CFCs),
along with bromine compounds, and supersonic jet airliners have been
uncertainly identified as being responsible for most of the anthropogenic
destruction of stratospheric ozone (O3) depletion issue occurred as a global
environmental threat.
This work will show some of the stratosphere characteristics and trace its
development, its role in atmospheric thermodynamics and impact on climate
change. Furthermore, it may propose some actions to build a scientific group
or network for further research on the stratosphere.
II. Characteristics of the stratosphere
The stratosphere is the second layer, above the troposphere and below the
mesosphere as one moves upward from the surface of the Earth. Its altitude
varies with latitude and climatic seasons with an approximately width of 35 km
in average, ranges between its bottom around 16 km (10 miles) above Earth's
surface near the equator, around 10 km (6 miles) at mid-latitudes, and around
8 km (5 miles) near the poles. The stratosphere is slightly lower in winter at
mid- and high-latitudes, and slightly higher in summer. The boundary between
the stratosphere and the troposphere is called the tropopause (dT/dz = 0),
while the boundary between the stratosphere and the mesosphere above is
called the stratopause. The top of the stratosphere occurs at 50 km (31 miles)
altitude.
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IV. The Ozone layer
The stratosphere contains a thin layer of ozone molecules (with three oxygen
atoms) which forms a protective layer shielding life on Earth from the Sun’s
harmful ultraviolet radiation. But this ozone layer which forms 90% of ozone is
being depleted, and is getting thinner over Europe, Asia, North American and
Antarctica. The IPCC assessment reports attribute this depletion to CFCs and
other GHGs.
V. Meteorology of the stratosphere
The dynamics and interactions between the stratosphere and troposphere
represented in the mean zonal flow may called Troposphere –StratosphereTroposphere (TST) circulation. The causes of TST events that observed to
propagate downward from the stratosphere into the troposphere are planetary
waves dissipate, and mix potential vorticity in the stratosphere which result a
mean flow. Many studies recommend further work to understand the
stratosphere troposphere coupling and strongly believe it needs to be given
much more attention considering its importance due to:
1 - the IPCC scenarios of precipitation and temperature patterns changes in
many regions of the world and its impact on the global weather and
climate,
2 - the climate change studies on the role of stratosphere circulations in
determining the distribution variability of ozone. And the effect of human
pollutions on the ozone layer,
3 - the fact that stratospheric circulation could play a significant role in future
climate change in the extra tropics and
4 - the stratosphere and troposphere dynamical interactions.
VI. Stratosphere and climate change
The variations of ozone concentration in the stratosphere have certain
chemical and environmental effects on global warming; climate variability
appears in wind and rainfall fluctuations, and climate change scenarios
projected by global and regional prediction models. The reduction and
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decrease of ozone in the stratosphere causes an increase of UV-B radiation
to the troposphere which may lead to harm health disease and its severe
circumstances.
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