Image of TOMS ozone hole data and a graph of changes in ozone hole area, 1996-2005, produced in a spreadsheet application. Click image for larger view.
In this chapter, students download and analyze ten images showing the area of the ozone hole from 1996 through 2005. They then use image analysis software to highlight, outline, and measure pixels that show ozone measurements of 225 Dobson Units or fewer.
Measurement results are imported into a spreadsheet application to produce a graph showing how the size of each October's ozone hole changed over ten years. (Click the thumbnail, right, for a larger view.)
After completing this chapter, students will be able to:
- interpret satellite images to understand the global distribution of ozone;
- identify the Antarctic ozone hole in satellite images;
- analyze images to quantify the area of the ozone hole over time; and
- produce a graph showing the area of the ozone hole over time.
This chapter gives students practice gathering data from satellite images. By examining images and the associated color scale, students learn to interpret color-coded satellite imagery. Identifying areas on images where ozone levels are below a threshold value gives students a way of visualizing what has been termed a "hole" in the ozone layer. This type of analysis can be extended to other data so users can interpret images depicting a wide variety of measurements.
Information about Ozone:
- Good Up High, Bad Nearby from the U.S. Environmental Protection Agency
- Ozone Fact Sheet from NASA's Earth Observatory
Information about Ozone Depletion and the Ozone Hole:
- World of Change: Antarctic Ozone Hole
- NASA's Ozone Hole Watch site
- The Ozone Hole Tour
- Tango in the Atmosphere
- EPA's Ozone Depletion Resources
- NASA: Antarctic Ozone Hole
Information about UV Radiation's Health Effects on Humans
- For more information about how UV affects humans, you can download the Practical Guide to the Global UV Index (429 KB pdf).
The following National Science Education Standards are supported by this chapter:
- 8ASI1.3 Use appropriate tools and techniques to gather, analyze, and interpret data.
- 8ASI1.8Use mathematics in all aspects of scientific inquiry.
- 8BPS1.2 Substances react chemically in characteristic ways with other substances to form new substances (compounds) with different characteristic properties.
- 8DESS1.8 The atmosphere is a mixture of nitrogen, oxygen, and trace gases that include water vapor. The atmosphere has different properties at different elevations.
- 12D1 Organize information in simple tables and graphs and identify relationships they reveal.
The following U.S. National Geography Standards are supported by this chapter:
- How to use maps and other geographic representations, tools, and technologies to acquire, process, and report information from a spatial perspective
- The physical and human characteristics of places
- How physical systems affect human systems
- Case Study: 10 minutes
- Part 1: 30 minutes
- Part 2: 10 minutes
- Part 3: 30 minutes
- Part 4: 30 minutes
These Microsoft Excel files can be used as in-class examples or as an assessment of student work.
- Results for Ozone Analysis (Excel 88bytes Aug5 11)
- Completed Graph for Ozone Analysis (Excel 18kB Aug5 11)
Current Ozone Data: 2004-2022
Earth Probe, the satellite carrying the TOMS instrument, was deactivated in December 2006. Current ozone data is available for analysis from the Ozone Monitoring Instrument (OMI) on the Aura satellite. The data can be accessed and downloaded from OMI Ozone website. Select the imagery tab and click the radio button associated with South Pole Images. Recall that the most likely date for the Ozone hole formation is late September or early October. Download the images and use the techniques described in Parts 3 and 4 to analyze the images.
Compressed File of Ozone Data
If you are unable to locate the files for this activity, or would rather start with a complete set of images, follow the instructions below.
- Download a compressed file that contains the TIFF images:
Right-click (ctrl-click on Macs) this link to download a zipped file of the TIFF images ( 369kB Jan30 07). Choose the "Download Link to Disk" or "Save Link As..." option. Once the file downloads, you may need to double-click it to decompress it. The decompressed file will be a folder named Ozone TIFFs. Open the images from within the ImageJ application as directed in Step 1 of Part 2.
- Alternately, if you're not successful with the link above, try this compressed file ( 538kB Apr4 06) instead.