| Ozone: Stratospheric Ozone
Ozone vs. UV Index
UV and Ozone Databases
The data that we are going
to use this week comes from two different sources. The
stratospheric ozone data comes from the NASA Total Ozone Mapping
Spectrometer (TOMS) satellite. This satellite has recorded
the ozone thickness over the entire almost every day for the
last 7 years. Luckily, the friendly people at NASA have built a nice
search engine that allows one to extract ozone thickness data from any location
at any time. This search engine is found at the address
http://toms.gsfc.nasa.gov/teacher/ozone_overhead.html
The UV data comes from
an NSF-sponsored monitoring unit at the Scott-Amundson
station at the South Pole. Biospherical Instrument, Inc. in
San Diego has developed an interactive database for the NSF that
allows one to retrieve UV Index data for this site. This
database can be found at
http://www.biospherical.com/nsf/student/CSVRequest.asp
Clicking on either of
these links will bring up a window that has the interface
required to retrieve the data from each site. From these interfaces,
we are going to want to retrieve ozone thickness and UV Index
data for dates that you have decided upon. To do this,
follow the directions below.
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Retrieving UV Index Data
(http://www.biosperical.com/nsf/student/CSVRequest.asp):
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1.
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Select
your Start Date.
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2.
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Select
your End Date .
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3.
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Select the South Pole as
your site from the pull-down menu. |
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4.
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Select the Irradiance Data
that you want. Choose the UV Index data only
(ozone does not absorb UVA). |
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5.
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Select "Retrieve Only Noontime
Scans". This will ensure that the data was taken
at the same time every day. |
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6.
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Click on Submit. |
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Retrieving
Ozone Thickness Data (http://toms.gsfc.nasa.gov/teacher/ozone_overhead.html):
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1.
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Enter
-90 for the Latitude and 0 for the Longitude.
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2.
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Select
a set of Year, Month, and Day that corresponds to your first UV Index data
point.
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3.
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Click on Submit, and write down the value
for the Ozone Thickness in Dobson Units. |
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4.
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Click on the Back button at the top of the
browser to take you back to the first page. |
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5.
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Repeat with the same Latitutde and Longitude,
but a different Year, Month, and Day. |
Activity Sheet Directions
Before
entering you data onto the activity sheet, be sure to multiply both the UV
Index data and the Ozone Thickness data by the appropriate factor for that
day (see factor table). Enter the UV
data (from the NSF site) and the Ozone thickness data (from
the NASA TOMS satellite) in the appropriate cells in the
table. Once all the data has been entered, make a plot
of UV Index vs. Stratsopheric Ozone Thickness. As plotting
requires both measurements for a given day, you cannot plot
days where you only have one measurement (either the UV Index
or Stratsopheric Ozone Thickness)
for that day. If ozone
does absorb ultraviolet radiation, then this data should
show that the UV Index decreases as the ozone thickness increases.
This will be seen from a plot of your data.
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