Struggle Seen As Sun Switches Magnetic Field Polarity [ 2001 ]

During solar maximum, when the Sun's activity is at a peak in its 11 year cycle, the polarity of its magnetic field changes: the north pole takes on the polarity of the south pole and vice versa. Now, for the first time ever, a spacecraft has witnessed this process from a front-row seat high above the Sun's south pole... Andre Balogh, from Imperial College, London, who is Principal Investigator for the Ulysses magnetometer, says: ..."Clearly, a struggle is going on in the Sun's magnetic field, with freshly emerging new polarity regions racing towards the polar regions, encountering the slowly decaying older polarity regions. We know that the new polarity will win through, but the battle is still on for another few months." ... "We know that the magnetic field configuration is completely different from how it was at solar minimum -- and these particle observations will help us to understand these differences in detail," says Richard Marsden, Ulysses Project Scientist from ESTEC, the Netherlands, who has been examining data from the COSPIN experiment on board Ulysses.

http://en.wikipedia.org/wiki/Sunspot

Sunspot activity cycles about every eleven years. The point of highest sunspot activity during this cycle is known as Solar Maximum, and the point of lowest activity is Solar Minimum... Today it is known that there are various periods in the Wolf number sunspot index, the most prominent of which is at about 11 years in the mean... A modern understanding of sunspots starts with George Ellery Hale, in which magnetic fields and sunspots are linked. Hale suggested that the sunspot cycle period is 22 years, covering two polar reversals of the solar magnetic dipole field. Horace W. Babcock later proposed a qualitative model for the dynamics of the solar outer layers. The Babcock Model explains the behavior described by SpÃ¶rer’s law, as well as other effects, as being due to magnetic fields which are twisted by the Sun’s rotation.

http://en.wikipedia.org/wiki/Solar_cycle

The Schwabe solar cycle, Schwabe-Wolf cycle, or sunspot cycle is the eleven-year cycle of activity of the sun, discovered in 1843 by the German astronomer Heinrich Schwabe. Since 1849 it has been measured using the Wolf number, based on the number of sunspots observed on the Sun. The cycle is also associated with the reversal of the solar magnetic polarity. The solar cycle is not strictly 11 years long; it has been as short as 9 years and as long as 14 years in recent years. Other possible cycles have been suggested, and are discussed in the article on solar variation.

http://zebu.uoregon.edu/~soper/Sun/cycle.html

“The number of sunspots reaches a maximum about every 11 years, but successive maxima have spots with reversed magnetic polarity. Thus the whole cycle is 22 years long. The record of observations indicates that this cycle has been going on back to the early 1700’s, although the strength of the cycle varies. For the period 1645 to 1715 the record is rather spotty, but suggests that there were hardly any sunspots. The luminosity of the Sun increases a little when there are sunspots. During the period 1645 to 1715 the Earth was unusually cold.”

http://solarscience.msfc.nasa.gov/SunspotCycle.shtml

The Maunder Minimum

Early records of sunspots indicate that the Sun went through a period of inactivity in the late 17th century. Very few sunspots were seen on the Sun from about 1645 to 1715 (38 kb JPEG image). Although the observations were not as extensive as in later years, the Sun was in fact well observed during this time and this lack of sunspots is well documented. This period of solar inactivity also corresponds to a climatic period called the “Little Ice Age” when rivers that are normally ice-free froze and snow fields remained year-round at lower altitudes. There is evidence that the Sun has had similar periods of inactivity in the more distant past. The connection between solar activity and terrestrial climate is an area of on-going research.

The Maunder Minimum isn't a regular cycle, but proxy data shows that the markedly cooler climate periods (going back at least eight thousand years) correspond to solar activity. Climate is 100 per cent natural, 100 per cent of the time.

Small Organisms, Great Proxies
University of Arkansas
Monday, October 23, 2006
The present and past compositions of communities of single-celled algae in several Canadian lakes and their relationship to the known climate record suggest that these organisms and the lakes they reside in are highly influenced by sun spot cycles, says a University of Arkansas researcher. In addition, the paleorecord of the fossilized organisms from one of the lakes reflects a climate-changing event at the end of the last Ice Age more than 8,000 years ago. Together, these findings indicate that fossil diatoms in lake sediments provide a strong proxy for paleoclimatic and paleoenvironmental change... The fossil record at lac du Sommet also recorded changes in the diatom community concentrations that indicate a response to local climate warming about 8,400 years ago, caused by the collapse of the ice dome in the Hudson Strait region and the rerouting of the melt-off stream from the Laurentian Ice Sheet. This event is related to a climate cooling observed in Europe around 200 years later, known as the 8.2 K event. The date of the ice dome collapse remains to be determined; Hausmann and colleagues St. Onge and Patrick Lajeunesse of UniversitÃ© Laval in Quebec, Canada, are working on a project involving sediment cores in the Hudson Bay, where Hausmann is studying the shift from freshwater to marine diatoms.
Is polar meltdown just hot air?
by Nicola Jones
March 17 2001
New Scientist
The North Pole isn't melting after all, says a researcher in Sweden.

Recent reports that ice in the Arctic is rapidly disappearing have been taken as graphic proof of global warming. But a more extensive study now shows the ice hasn't thinned at all since the late 1980s.

Peter Winsor from the University of Gothenburg in Sweden looked at data from 1986 to 1997 showing sea ice thickness throughout the Arctic. The data had been collected by submarines cruising under the ice and firing sonar pulses upwards to determine its thickness. After adjusting the data to account for seasonal differences, he found the volume of ice in the Arctic had stayed nearly constant.

This contradicts a major study in 1999, which found that the thickness of Arctic sea ice had decreased by a startling 1.3 metres since 1958 -- more than a third of its current thickness -- and continues to drop by .1 metres per year. Winsor says his results differ simply because they're based on more data.

"Recent reports of the demise of the Arctic ice cover have likely been greatly exaggerated," says Bill Hibler from the International Arctic Research Center in Fairbanks, Alaska. "It's probably a lot tougher than many recent reports suggest." Winsor says his study doesn't mean the planet isn't heating up. But it does point to flaws in climate models which predict that Arctic ice will be drastically affected by global warming.

More at: Geophysical Research Letters (vol 28, p 1039)

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