Cycle 24 Here, Experts Say
Solar physicist David Hathaway of NASA's Marshall Space Flight Center in Huntsville, Alabama concurred, saying that new solar cycles begin with a "modest knot" of magnetism, like the one that appeared on December 11 on the east limb of the Sun: "That patch of magnetism could be a sign of the next solar cycle. New solar cycles always begin with a high-latitude, reversed polarity sunspot." The region of magnetism that appeared back in December achieved high latitude (24 degrees North) and was magnetically reversed, but no supporting sunspot appeared until 25 days later.
Reversed polarity means a sunspot with opposite magnetic polarity compared to sunspots from the previous solar cycle. High-latitude refers to the Sun's grid of latitude and longitude. Old-cycle spots congregate near the Sun's equator; new-cycle spots appear higher, around 25 or 30 degrees latitude. Sunspot 981's high-latitude location at 27 degrees North and its negative polarity leading to the right in the Northern Hemisphere are clear-cut signs of a new solar cycle, according to NOAA experts. The first active regions and sunspots of a new solar cycle can emerge at high latitudes while those from the previous cycle continue to form closer to the equator.
Solar Cycle 24 Predictions
While experts vary in their predictions on when the solar cycle will peak and how strong it will be, NOAA, in April 2007, in coordination with an international panel of solar experts, predicted that the next 11-year cycle of solar storms "would start in March 2008, plus or minus six months, and peak in late 2011 or mid-2012." In the cycle forecast issued in April 2007, half of the panel predicted a "moderately strong cycle of 140 sunspots, plus or minus 20, expected to peak in October 2011. The other half predicted a moderately weak cycle of 90 sunspots, plus or minus 10, peaking in August 2012. An average solar cycle ranges from 75 to 155 sunspots. The late decline of Cycle 23 has helped shift the panel away from its earlier leaning toward a strong Cycle 24. The group is evenly split between a strong and a weak cycle."
NASA's Hathaway, along with colleague Robert Wilson at a meeting of the American Geophysical Union in San Francisco last month, said that Solar Cycle 24 "looks like it's going to be one of the most intense cycles since record-keeping began almost 400 years ago." They believe the next solar maximum should peak around 2010 with a sunspot number of 160, plus or minus 25. "This would make it one of the strongest solar cycles of the past fifty years -- which is to say, one of the strongest in recorded history." Four of the five biggest cycles on record have come in the past 50 years. "Cycle 24 should fit right into that pattern," Hathaway said.
Amateur Radio and Solar Cycle 24
According to Carl Luetzelschwab, K9LA, "As for improvement in propagation on the higher bands, we still have a way to go before that happens, and it depends on the magnitude of Cycle 24. The Solar Cycle 24 Prediction Panel has published predictions for Cycle 24, but unfortunately the panel did not reach one consensus prediction. If the larger of the two predictions comes true, we should expect consistent F2 propagation on 10 and 12 meters to start toward the end of 2009. If the smaller prediction comes true, this will be delayed about one year."
Luetzelschwab, who writes the column "Propagation" for the National Contest Journal (NCJ), continued: "While we wait for improved high band conditions, don't forget the low bands. Around solar minimum and for the next year or so, the Earth's geomagnetic field is at its quietest. This is good for low band propagation. Thus, right now is the time to start (or add to) your 80 and 160 meter DXCC efforts."
Active Solar Cycles Bring Sunspots, Solar Storms
A sunspot is an area of highly organized magnetic activity on the surface of the sun, and is marked by a lower temperature than its surroundings. The new 11-year cycle, called Solar Cycle 24, is expected to build gradually, with the number of sunspots and solar storms reaching a maximum by 2011 or 2012, though devastating solar storms can occur at any time
While sunspots are good news to Amateur Radio operators, an active solar cycle can disrupt other aspects of life that we take for granted, since violent eruptions occur more often on the Sun during an active period. According to NASA, solar flares and vast explosions, known as coronal mass ejections, shoot energetic photons and highly charged matter toward Earth, jolting the planet's ionosphere and geomagnetic field, potentially affecting power grids, critical military and airline communications, satellites, Global Positioning System (GPS) signals and even threatening astronauts with harmful radiation. These same storms illuminate night skies with brilliant sheets of red and green known as auroras, or the northern or southern lights.
NOAA Administrator and Under Secretary of Commerce for Oceans and Atmosphere Vice Admiral (Ret) Conrad C. Lautenbacher, Jr said, "Our growing dependence on highly sophisticated, space-based technologies means we are far more vulnerable to space weather today than in the past. NOAA's space weather monitoring and forecasts are critical for the nation's ability to function smoothly during solar disturbances."
According to NASA's Tony Phillips, many forecasters believe Solar Cycle 24 will be big and intense. Solar cycles usually take a few years to build to a frenzy and Cycle 24 will be no exception. "We still have some quiet times ahead," says Hathaway.