by Wm. Robert Johnston
last updated 26 December 2002
Description: The red line shows monthly average ozone over the equatorial region from 5°S to 5°N. The blue line shows a twelve-month moving average for the same data. The measurements are from various satellite-based instruments.
Comments: The equatorial region shows less cyclical variation in ozone levels than other regions, but several cycles are evident here. The annual cycle is most obvious. A cycle with a period of 10 years (maxima in 1980, 1990, and 1999) is also visible and is tied to the solar activity cycle with an 11-year period. There is also a two-year cycle that is not obvious.
Source: NASA TOMS, on line.
© 2001, 2002 by Wm. Robert Johnston.
Last modified 26 December 2002.
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