1. Melissa Montoya [†], Dr. Ken Minschwaner [††], Dr. Gloria Manney [‡]
Introduction
In the winter, Antarctica
experiences three to four
months of darkness; it is
during this time that the
ingredients for ozone
depletion start gathering. But
it isn’t until Spring, when the
sun reappears, that ozone
depletion occurs.
Where did the chlorine
compounds come from?
Antarctic Winter: May-August
Key initial conditions:
 Low temperatures: -85°C
 Strong Antarctic polar vortex
 Formation of polar stratospheric clouds
(PSCs) composed mainly of nitric acid
trihydrate and water ice.
Antarctic Spring: September-October
 Sunlight triggers chemical reactions that produce ClO.
 This leads to chemical ozone loss
Why should I care?
Stratospheric ozone is
important to the global
environment because it is
responsible for controlling
the temperature of Earth’s
stratosphere and absorbing
ultraviolet UV-B radiation
from the Sun. UV-B radiation
increases the risk of skin
cancer and cataracts,
damages DNA, and leads to
a suppressed immune
system.
Acknowledgements:
Let’s take a closer look at the
chemical reactions that destroy
ozone in the polar stratosphere
http://cartina.photo/kuvapankki/imagebank/image/37/37721/polar+stratospheric+cloud.jpg
Temperatures measured by
the Microwave Limb Sounder
(MLS) on the NASA Aura
Satellite for July 1, 2014 at
~18 km altitude.
• Chemical reactions on PSC
particles convert gas phase
hydrochloric acid (HCl) to
ozone destroying Cl.
http://mls.jpl.nasa.gov/plots/mls/maps/MLSDailyThetaMap-SH_v03-43-c01_2014d182.png
ClO, HCl, and O3 measured by MLS on September 16, 2014 at ~18 km altitude.
Chlorine comes from Chlorofluorocarbons
(CFCs) that were initially released into the
atmosphere starting in the 1960’s. The
are still being released but they are no
longer produced commercially.
One reason that we are concerned about
CFCs is because their atmospheric
lifetimes range between 50-150 years.
Past measurements of CFC mixing
ratios and modeled future mixing
ratios based on a range of
assumptions from future emissions.
WMO- 2002 Ozone Assessment
†-CNM and AMP/SCCORE ††-NMT Physics ††- NMT Physics and Northwest Research Associates
I want to thank the AMP/SCCORE program for allowing me to have this amazing opportunity; Michael Voegerl for patiently guiding me
through this process; Zachary Lawrence for providing critical technical support; and the NMT Physics department for their assistance
and kindness.