I'm looking forward to the coming decade of colder winters... :-)
Dalton Minimum Returns
21 Apr 09 - Paul Stanko of NOAA writes meteorologist Anthony Watts to tell him of an interesting development in his tracking of the International Sunspot Number (ISN).
Paul writes:
My running mean of the International Sunspot Number for 2009 just dipped below 1.00. For anything comparable you now need to go back before 1913 (which scored a 1.43) which could mean we're now competing directly with the Dalton Minimum. Just in case you'd like another tidbit, here is something that puts our 20 to 30 day spotless runs in perspective… the mother of all spotless runs (in the heart of the Maunder Minimum, of course!) was from October 15, 1661 to August 2, 1671. It totaled 3579 consecutive spotless days, all of which had obs. To say that that we in interesting times is a huge understatement. We are about to enter a Grand Minimum, which in the past have produced a cooler planet, while our government is preparing for run-away global warming. Who could have predicted this stupidity?
Is a new Dalton Minimum approaching?
Russ Steele
Well 2008 arrived last night and Sunspot Cycle 24 was absent. While we had a flurry of excitement a few week ago when a patch of reverse polarity showed on the Suns surface it soon faded. The Sun reverses polarity with each cycle change. As we have discussed in the past the length of the roughly 11-year sunspot cycle is correlated with temperature and a late arriving cycle can have some long term climate implications for us folks here on Earth. The Cycle 23 solar minimum was at 1996.5, so with an average 11 year cycle we should have seen the new minimum in mid-2007. Here we are in 2008 and the next cycle is already six months late, and the defining minimum generally occurs 12-20 months after the first spot of the new cycle. This would indicate the ending minimum of Cycle 23 and the start of Cycle 24 will come in mid 2009, resulting in a 13 year cycle, the longest since 1784-1797. Interesting to note that this cycle started a long series - 13.6, 12.3, 12.7 years, which coincided with the cold period known as the Dalton Minimum. Stay tuned, these are going to be interesting times. Sun cycles indicate cooling and the politicians are trying stop global warming. We may need a little extra warming over the next thirty years.
Thanks to David Archibald for this graphic showing the relationship of cycle length to temperature in New Hampshire.
Dalton Minimum
The Dalton minimum in the 400 year history of sunspot numbers The Dalton Minimum was a period of low solar activity, named for the English meteorologist John Dalton, lasting from about 1790 to 1830. Like the Maunder Minimum and Spörer Minimum, the Dalton Minimum coincided with a period of lower-than-average global temperatures. The Oberlach Station in Germany, for example, experienced a 2.0° C decline over 20 years. The Year Without a Summer, in 1816, also occurred during the Dalton Minimum.
By Robert Roy Britt
Senior Science Writer
posted: 27 October 2004
12:58 pm ET
Sunspots have been more common in the past seven decades than at any time in the last 8,000 years, according to a new historic reconstruction of solar activity.
Many researchers have tried to link sunspot activity to climate change, but the new results cannot be used to explain global warming, according to the scientists who did the study.
Sunspots are areas of intense magnetic energy. They act like temporary caps on upwelling matter, and they are the sites of occasional ferocious eruptions of light and electrified gas. More sunspots generally means increased solar activity.
Sunspots have been studied directly for about four centuries, and these direct observations provide the most reliable historic record of solar activity. Previous studies have suggested cooler periods on Earth were related to long stretches with low sunspot counts. From the 1400s to the 1700s, for example, Europe and North America experienced a "Little Ice Age." For a period of about 50 years during that time, there were almost no sunspots.
But a firm connection between sunspot numbers and climate remains elusive, many scientists say.
Better record
The new study, led by Sami Solanki of the Max Planck Institute in Germany, employed a novel approach to pinning down sunspot activity going back 11,400 years:
Cosmic rays constantly bombard Earth's atmosphere. Chemical interactions create a fairly constant source of stuff called carbon-14, which falls to Earth and is absorbed and retained by trees. But charged particles hurled at Earth by active sunspots deflect cosmic rays. So when the Sun gets wild, trees record less carbon-14.
While trees don't typically live more than a few hundred years or perhaps a couple thousand, dead and buried trees, if preserved, carry a longer record, "as long as tree rings can be identified," said Manfred Schuessler, another Max Planck Institute researcher who worked on the study.
The study's finding: Sunspot activity has been more intense and lasted longer during the past 60 to 70 years than at anytime in more than eight millennia.
Sunspot activity is known to ebb and flow in two cycles lasting 11 and 88 years (activity is currently headed toward a short-term minimum). Astronomers think that longer cycles -- or at least long-term variations -- also occur. Scientists in other fields have shown that during the past 11,000 years, Earth's climate has had many dramatic shifts.
"Whether solar activity is a dominant influence in these [climate] changes is a subject of intense debate," says Paula Reimer, a researcher at Queen's University Belfast who wrote an analysis of the new study for Nature. Why? Because "the exact relationship of solar irradiance to sunspot number is still uncertain."
In general, studies indicate changes in solar output affect climate during periods lasting decades or centuries, "but this interpretation is controversial because it is not based on any understanding of the relevant physical processes," study member Schuessler told SPACE.com. Translation: Scientists have a lot to learn about the Sun-Earth connection.
Better understanding
The study's methods appear solid: "The models reproduce the observed record of sunspots extremely well, from almost no sunspots during the seventeenth century to the current high levels," Reimer said.
The research could eventually help scientists understand why the climate has changed in the past and allow for better predictions of future change.
"The reconstructed sunspot number will nonetheless provide a much-needed record of solar activity," Reimer said. "This can then be compared with palaeoclimate data sets to test theories of possible solar-climate connections, as well as enabling physicists to model long-term solar variability."
Whatever the result, change is likely to continue.
Solanki's team calculates that, based on history, the chances of sunspot activity remaining at the currently high levels for another 50 years is 8 percent. Odds are just 1 percent the solar exuberance will last through the end of this century.