Sunspots, where have they gone?
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Credit: SOHO/MDI Spotless Sun 4/19/09
Currently, we are experiencing a deep solar minimum in the sunspot cycle. In fact, not one sunspot has been observed this month with the spotless day streak growing to 24 days straight. The current solar minimum is part of the pattern, and for the most part on time. I say for the most part because it seems many forecasts and scientific analogs pointed towards 2008 being the solar minimum with an increase in sunspot activity arising in 2009. The problem is the sunspot number continues to decrease in April of 2009.
What is a sunspot? Has this ever happened before? What implications are possible if sunspot numbers don’t increase anytime soon? These are questions I have researched and would like to share with you.
A sunspot is a planet-sized region on the Sun’s surface that is marked by intense magnetic activity, which inhibits convection and forms areas of reduced surface temperature (therefore making them “dark spots” on the sun). Sunspots are sources of solar flares, coronal mass ejections and intense UV radiation. Sunspot minimums come along every 11 years or so, and when plotting sunspot counts, we see peaks of solar activity are always followed by valleys of minimum solar activity.
Therefore, it is expected for the Sun to undergo minimum solar activity on a regular basis. 2008 was considered a very deep solar minimum where no sunspots were observed on 266 days out of the year (73%). Only one year during the last 100 years observed a lower sunspot activity, 1913 (85%). As of April 19th, there have been no sunspots observed on 96 out of the 109 days (88%) so far this year. However, sunspot activity has been lower on several occasions during the last 400 years.
So what implications would an extended solar minimum period mean for Earth? First I would start by saying there is a better chance than not that sunspot activity increases in the next few months and follows the cycle. For any reason it doesn’t, we should examine past examples of similar cases to see what this would mean for Earth.
According to NASA research, there is a cause-and-effect relationship between sunspot activity and measured changes in global temperatures on Earth. I strongly agree, as evidence shows us that the “Maunder Minimum” and “Dalton Minimum” were times where Earth experienced anomalously cold temperatures. The years surrounding the “Maunder Minimum” are now commonly called the “Little Ice Age”. “Dalton’s Minimum” combined with the eruption of Mount Tambora in 1815 set the stage for the “Year Without a Summer” in 1816, as it is commonly referred.
Earth’s surface temperature saw a drop in 2008, which I think is no coincidence given the deep solar minimum. IF, we were to see a “Maunder Minimum” type of sunspot activity occur over the next few decades, the world’s economy and agriculture would suffer tremendously. Many scientists who believe in global warming speculate that this deep solar minimum we are currently experiencing will keep global temperatures from rising over the next few years until sunspot activity increases towards the next predicted maximum in 2012 or 2013. Climate change is a much heated debate in the scientific community; however the one mechanism that both sides agree upon which influences earth’s surface temperature is sunspot activity.
Data was collected from the National Geophysical Data Center . Matlab was used for plotting.
As mentioned previously, it should be a matter of time before the solar cycle corrects itself and solar activity increases towards the next maximum. Nonetheless, extended solar minimums have been observed in recent history and if it were to occur, would have tremendous impacts on the world’s economy and agriculture.
If you would like to keep up to date on sunspot numbers, visit this site daily for the latest on solar activity.
