2016-02-24. Sun's Magnetic Fields Best at Forecasting Solar Cycle Peaks.

posted Feb 26, 2016, 10:39 PM by Alan Gould
By Aleida K. Higginson, EoS-Earth & Space Science News, AGU. For GSS Energy Flow chapter 4. Excerpt: Solar activity level rises and falls every 11 years. The most recent maximum in solar activity level, the 24th since recording began in 1755, was the weakest in almost 100 years and peaked in early 2014.  Solar activity refers to dark regions on the surface of the Sun called sunspots, where the Sun’s magnetic field has become tangled. They can produce sudden explosions of energy in the form of intense radiation and energetic particles. Sometimes, these regions will even kick out a portion of the tangled magnetic field and send it hurdling into space in an event called a coronal mass ejection. When these bursts of radiation, particles, and magnetic field reach Earth, they cause geomagnetic storms, which can interfere with communication satellites and power grids on the ground. These events could also be harmful to astronauts traveling to Mars, exposing them to possibly deadly amounts of radiation. ...a new study by Pesnell compares all of the predictions to determine which forecasts were the most accurate. ... For past solar cycles, models using geomagnetic activity level made more accurate predictions, but this accuracy may be due to the fact that solar polar magnetic field data were scarce or unreliable. This time, for solar cycle 24, the models using polar magnetic fields made the best predictions by far.  ...solar cycle 25, slated to begin as early as 2020.... (Space Weather, doi:10.1002/2015SW001304, 2016)...  https://eos.org/research-spotlights/suns-magnetic-fields-best-at-forecasting-solar-cycle-peaks