Ozone column at five U.S. sites, 1964-1998
by Wm. Robert Johnston
Ozone column measurements, annual averages, US sites
last updated 26 December 2002
Description: This is data from five U.S. sites (including the average of the five sites) as follows:
- Caribou, Maine, 46.9° N (dark green)
- Bismark, North Dakota, 46.8° N (brown)
- Nashville, Tennessee, 36.2° N (magenta)
- average of listing US sites (red)
- Boulder, Colorado, 40.0° N (light green)
- Mauna Loa, Hawaii, 19.5° N (blue)
Comments: The graph indicates the following:
- Significant differences in average ozone column between locations, exceeding 15% for these sites (trend is for greater values further from the equator);
- Significant year-to-year variation, up to 5%;
- An overall decrease of about 5%, with most of this decrease after 1980;
- Three sites recording the lowest annual average in 1993, with all sites showing an increase from 1993 to 1998.
© 2001, 2002 by Wm. Robert Johnston.
Last modified 26 December 2002.
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