OZONE DEPLETION



South Pole January 1, 1996

South Pole March 1, 1996

South Pole May 1, 1996

South Pole July 1, 1996

South Pole September 1, 1996

South Pole October 1, 1996

South Pole November 1, 1996

South Pole December 17, 1996

South Pole - Complete month of September, 1996

South Pole - Complete month of October, 1996

South Pole - Complete month of November, 1996

South Pole - Sequence of Ozone Hole Pictures - Sept. to Nov. 1994

South Pole - Sequence of Ozone Hole Pictures - 1979-1993

South Pole - Ozone Size Graph

South Pole - Ozone Concentration Minima in Dobson Units (DU)

South Pole - Ozone Altitude Profile 1993 &1995

South Pole - Ozone Altitude Profile - Springtime Progression for 1993

Ozone Concentration Measured over Switzerland

North Pole - Ozone Maps for 1979 to 1993


Ozone depletion over North America 79 vs 94

Explanation of the South Pole Wind Vortex

South Pole - Movie of Polar Vortex

HCl profile with altitude

HF profile with altitude
The above two graphics are part of the proof that CFCs cause the ozone problem because the HCl and HF profiles are very similar. HF has no known natural source, therefore HF could not get into the stratosphere except through CFCs. Pamela Zurer, "Satellite Data Confirm CFC Link in Ozone Hole", C and E News, January 2, 1995, p. 9.

 

Ozone layer depletion Links
 A. Caused by synthesis and use of chlorofluorocarbons (CFCs) Ozone Layer
Ozone Depletion - Specific brief Questions and Answers on ozone depletion only.
General information on ozone science - a general review
Ozone Hole Tour - Cambridge University, UK
Simple graphic of Ozone depletion
Ozone Hole - animation of the ozone hole in 1995.
Graph of ozone vs. altitude
Graphs showing comparison of ozone over North America - 1979 and 1994.
Ozone maps - South Pole 1979-1997
Ozone maps - Nouth Pole 1979-1998
Archive of ozone hole maps - Listed by most recent dates first. Click on the icon that says S.H. GIF for southern hemisphere.
EPA Home Page on Ozone - contains many links to other pages. Look here if interested in more information.
Controversy surrounding ozone depletion - This is a brief review of two opposing papers on several questions concerning ozone depletion.
Common Myths about the nonexistence of the ozone problem - a series of links.

Ozone Executive Summaries by Year
 B. Effects Health Effects from overexposure to UV
UV Index - Series of links relating to health issues and the UV Index. Includes a link to a National map of the daily UV Index.
C. Possible control measures - Montreal Protocol Montreal Protocol - Ozone Depletion: 1987


 QUES. 3: OZONE DEPLETION - Answer ONE of the questions 3a-d below.

In 1987, an international agreement known as the Montreal Protocol on Substances that Deplete the Ozone Layer was signed by many nations. The Protocol required the that CFC production would be reduced to one-half of the 1986 levels by 1998. Based upon a growing understanding of the cause of the ozone hole and the potential for global ozone depletion, approximately 100 nations in 1990, agreed to a complete ban on the use of CFCs in 2000.

Visualization of the Ozone Hole:

A site is available to access contour color maps of the ozone concentrations in various locations in the world. The longest archived series is from a satellite carrying TOMS - Total Ozone Mapping Spectrometer. Another satellite provides daily maps called TOVS.
TOMS: EARTH PROBE TOMS HOME Page.

NOTE: These are new directions from those printed in the lab manual because they keep changing this site.

a. Click on Today's Ozone Data and Images to get current real time data. The color contour coding shows low ozone concentrations measured in Dobson units of dark purple, pink, violet colors. White or black colors mean that no data is available. Use the Back button to return to the Earth Probe TOMS Data and Images Page.

USE the following to answer QUES. 3a and 3b.
b. Use Earth Probe TOMS, click on "South Pole Ozone - GIF".Then there is a section that will allow you to choose a year (1996-1999) Then pick the year month and day. This is a direct link to an image for a specific date. If you get tired of doing one at a time then continue to c.
OR
c. It is also possible to get a GIF animation of polar views. This may play slowly or quit.

QUES. 3a: First concentrate on the Antarctica, look at a series of images starting with July 1 and look at one or two date every month until December. You may need to go back an get some of the 1997 dates for November and December. Which months show evidence of the "ozone hole"? Evidence of the ozone hole is when you begin to see contours of blue, purple, pink, or dark purple. See the color bar for the Dobson Units near the bottom of the graphic. In July and August you will see a black spot on the south pole - this is NOT the ozone hole, but only a lack of data due to the fact that the satellite can not work when it is comptely dark at the poles as it is in the winter which is July and August. Try to refine the dates for the optimal duration of the ozone hole. Try some dates that are about 15 days apart. What day(s) does the ozone hole begin(probably sometime in August or early September) and end (probably near end of November or early December) ?

Note: use the above www site to find answers to the above questions and those that follow:

QUES. 3b: For the Antarctica Ozone Hole give the approximate date and lowest concentration of ozone, in Dobson units, observed. Comment about the ozone hole growing in area size and the minimum concentration as the years have incrreased. Series of monthly ozone maps.

Examine the ozone and reactive chlorine versus latitude graph # 1. What is most striking about the relationships shown on the graph? As the latitude increases (getting closer to the South Pole) the ozone concentration _________ while the chlorine concentration __________.

1999 Ozone Hole - graphs of concentration and size compared to earlier years.

Brief explanation for the ozone hole. The inactive forms of chlorine in hydrochloric acid and chlorine nitrate can react with ice crystals and nitric acid trihydrate crystals in very high cold clouds in the stratosphere over Antarctica. This reaction on the surface produces diatomic chlorine molecule and nitric acid, which quickly dissociate into chlorine atoms in the sunlight of the Antarctic spring. The reactive chlorine atoms start a cycle of destruction of ozone. Chlorine atoms react with ozone to make chlorine monoxide molecules and oxygen molecules. Chlorine monoxide reacts with atomic oxygen to make diatomic oxygen and reactive chlorine atoms to cycle over again. Since there are few gaseous water molecules and virtually no nitrogen dioxide molecules to react with and inactivate the chlorine, the reactive chlorine builds up as chlorine monoxide and recyles to chlorine atoms which continue to destroy more ozone.

QUES. 3c: From Earth Probe TOMS, click on "Global Ozone". Pick a date in July, and year. Use the color contours to list the approximate ozone concentrations over three zones: near the equator, in the mid latitudes (North America/Europe/Asia) and polar regions. Is the distribution of ozone uniform over the surface of the globe?

U.V, Map of U.S. showing contours of where the most U.V . of the type that damages DNA. Lower numbers equals less U.V . (Contrast aqua contour with purple or brown contour. AND correlate that with the %per year cancer rate.

Based upon this analysis, where would you NOT want to live on a permanent basis because of increased exposure to UV due to lower ozone concentrations and possible increased risk of skin cancer? Closer to poles or closer to the equator? Northern U.S. or Southern U.S.?


QUES. 3d: Is there any evidence of a similar ozone hole hear the North Pole? Look particularly at dates in March and April. Use Earth Probe TOMS, click on "North Pole Ozone - GIF". Pick some dates in March and April, and year. There is a more definite effect in 1997. You are looking for aqua blue colors right at the north pole as they indicate a lower concentration in Dobson units as indicated by the color bar on the bottom. Again a black hole is just a lack of data and is NOT an ozone hole. Here is a series of North Pole images from 1979 to 1998. Look carefully at the color coding and note that the levels are not as low as those over the South Pole. n the bottom. Again a black hole is just a lack of data and is NOT an ozone hole. The evidence for an ozone hole in the spring at the North pole is not as dramatic and nor as serious as the ozone hole at the South Pole in the southern hemisphere spring (Sept-Nov.) Series of ozone Norh Pole maps - 1979-98.

 

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