1. The year 1990 (upper image), which was
a period of high solar activity with many (150) sunspots.
2. The year 1996 (lower image), which was
a period of low solar activity with few (10) sunspots.
The plots show electron density contours, which are an indication of the amount of ionization in the atmosphere. Yellows and reds indicate larger ionization and blues and greens indicate smaller ionization. Notice the substantial differences in these two animations, with much stronger atmospheric ionization in the upper image (the active Sun of 1990) than the lower image (the quiet Sun of 1996).
The adjacent images are based on these electron density contour maps of the ionosphere for months in the year 1957 to the present. Additional animations may be found in this NOAA directory.
Usage: Click the "Play" button to run the animation as a movie, or click the buttons for the individual months to go to the images for a particular month.