Above: This image, courtesy of Dr. Judith Lean at the
US Naval Research Laboratory, shows three extreme ultraviolet
(EUV) pictures of the Sun captured by the ESA/NASA Solar and
Heliospheric Observatory at different times during the current
solar cycle. In 1996, near solar minimum, the EUV Sun was nearly
featureless. Now, near the peak of the cycle, the Sun is dotted
by fiery regions of hot gas trapped in magnetic fields above
sunspots and plages. These active regions produce copious numbers
of EUV and X-ray photons that are absorbed in outer layers of
our atmosphere before they reach Earth's surface. The red curve
in the image is a computer model of the solar EUV flux at 304
Angstroms derived from ground-based Ca K images made at the Big
Bear Solar Observatory.
Above: By combining data about geomagnetic
activity during the previous solar cycle with sunspot counts
for the current cycle, David Hathaway and collaborators are able
to predict when the next
sunspot maximum will occur. [Click
here for details]. According to their results, the sunspot
number will peak beginning in mid-2000. The dotted lines above
and below the solid curve line indicate the prediction curve's
range of error. The vertical bars indicate the full range of
daily sunspot numbers that were averaged to obtain monthly data
points. Large excursions, like the one on April 2 when the daily
Boulder sunspot number reached 301, are not uncommon.
- Sunspot
Cycle Prediction
- Solar Radio Monitoring Programme
- 10.7cm Radio Flux Prediction
