Forecast for the Next Solar Cycle
Written by : LAM Hok-yin September 2006
Earlier in 2006, Dr. Mausumi Dikpati and her team of the National Center for Atmospheric Research (NCAR) used a computer model, first of the kind that employs solar dynamics, to forecast the solar activity in the coming solar Cycle 24. Results show that the activity may be about 30-50% higher than normal in the next solar maximum. In brief, the forecast was done by tracking the subsurface movements of the sunspot remnants of the previous two solar cycles.
The computer model, known as the Predictive Flux-transport Dynamo Model, indicates that the evolution of sunspots is caused by a current of plasma that circulates between the Sun's equator and its poles. This current acts like a conveyor belt of sunspots.
When sunspots decay, they leave a trail of magnetic signature on the moving plasma. As the plasma moves near the poles, it sinks and starts returning toward the equator. The increasingly concentrated fields become stretched and twisted by the internal rotation of the Sun as they approach the equator and become unstable. This eventually causes coiled-up magnetic field lines to rise up, press on the Sun's surface, and create new sunspots.
It shouldn't take long to see if the forecast is correct. Scientists predict that the next cycle should begin in late 2007 or early 2008.
Website of High Altitude Observatory, NCAR; Nature, 25 May 2006, p.402-404