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Here is an update on recent solar cycle activity and predictions.
Background
At The Old Farmer's Almanac, solar science is one of the disciplines we use to make our long-range weather predictions. In other words, we believe that weather on Earth can be influenced by solar activity. When the Sun is less active, it gives off less energy, and our planet is sometimes affected, often cooling down.
Sunspots, which are magnetic storms on the surface of the Sun, provide clues to the amount of solar activity.
What is a Solar Cycle?
The solar cycle is approximately 11 years long. The cycle is the interval between periods of low sunspot activity (successive minima). During a cycle, solar flares, sunspots, and other magnetic phenomena generally rise and then drop again.
Solar Minimum
According to many experts, sunspot activity may have reached its low or solar minimum in December 2008.
There was a deep lull in solar activity that began around 2007. In 2008 and 2009, the Sun set records for low sunspot counts. For 2009, 260 of the year's 365 days (71 percent) were sunspotless.
In September, 2009, Dean Pesnell of the Goddard Space Flight Center said, "We're experiencing the deepest solar minimum in nearly a century." Due to the weak solar activity, galactic cosmic rays were at record levels.
Solar Maximum
A panel of experts led by NOAA and sponsored by NASA has released a prediction for the next solar cycle. Solar Cycle 24 will peak in May 2013. It will be below average in intensity, with a maximum sunspot number of 90.
Of course, even a below-average sunspot count does not preclude a large solar flare—which could cause billions of dollars in damage to the world's high-tech infrastructure.
What's Up With the Sun Now?
In late 2009, we started to see some sunspot activity and signs of the awakening Solar Cycle 24, after an unusually long quiet phase.
Here are the latest reports:
- In October, 2009, the Sun showed a rare burst of activity. Sunspot 1029 unleashed multiple solar flares.
- December, 2009, ended with a "flurry" of sunspots. All of the month's sunspot groups have been members of new Solar Cycle 24.
- As of January 12, 2010, only one sunspotless day was reported on the Sun (8% of the year). Solar activity is definitely increasing. This may end quiet space weather conditions.
- On February 6 and 7, 2010, giant sunspot 1045 emerges, producing three M-class and almost a dozen C-class solar flares.
How Does Solar Activity Affect Earth?
- A quiet Sun usually means weak solar winds, which may allow more galactic cosmic rays into the inner solar system. This poses health risks for astronauts. Another effect is fewer aurorae, or northern lights, on Earth.
- An active Sun can generate geomagnetic storms that damage satellites and electrical grid infrastructure.
In terms of weather, there is also evidence that long-term periods of global cold, rainfall, drought, and other weather shifts relate to solar cycle activity:
- Times of depressed solar activity seem to correspond with times of global cold. For example, during the 70-year period from 1645 to 1715, few if any sunspots were seen even during expected sunspot maximums, and Western Europe entered a virtual deep-freeze known as the Little Ice Age.
- Conversely, times of increased solar activity have corresponded with global warning. During the 12th and 13th centuries, the Sun was active, and the European climate was quite mild.
Of course, many many other factors influence the Earth's weather.
We all have much to learn about our Sun! Stay tuned for solar activity updates.
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