[CW] MAJOR info on NEW solar info and what it means to (long, term) RF propagation and Climate.

[D.J.J. Ring, Jr.]

MAJOR info on NEW solar info and what it means to (long
term) RF propagation and Climate.
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Scientists predict rare 'hibernation' of sunspots

by Kerry Sheridan - Tue Jun 14, 5:38 pm ET

WASHINGTON (AFP) - For years, scientists have been predicting the
Sun would by around 2012 move into solar maximum, a period of
intense flares and sunspot activity, but lately a curious calm has

suggested quite the opposite.

According to three studies released in the United States on
Tuesday, experts believe the familiar sunspot cycle may be shutting
down and heading toward a pattern of inactivity unseen since the

17th century.

The signs include a missing jet stream, fading spots, and slower
activity near the poles, said experts from the National Solar
Observatory and Air Force Research Laboratory.

"This is highly unusual and unexpected," said Frank Hill, associate

director of the NSO's Solar Synoptic Network, as the findings of
the three studies were presented at the annual meeting of the
American Astronomical Society's Solar Physics Division in Las
Cruces, New Mexico.

"But the fact that three completely different views of the Sun
point in the same direction is a powerful indicator that the
sunspot cycle may be going into hibernation."

Solar activity tends to rise and fall every 11 years or so. The

solar maximum and solar minimum each mark about half the interval
of the magnetic pole reversal on the Sun, which happens every 22
years.

Hill said the current cycle, number 24, "may be the last normal one

for some time and the next one, cycle 25, may not happen for some
time.

"This is important because the solar cycle causes space weather
which affects modern technology and may contribute to climate
change," he told reporters.

Experts are now probing whether this period of inactivity could be
a second Maunder Minimum, which was a 70-year period when hardly
any sunspots were observed between 1645-1715, a period known as the
"Little Ice Age."

"If we are right, this could be the last solar maximum we'll see
for a few decades. That would affect everything from space
exploration to Earth's climate," said Hill.

Solar flares and eruptions can send highly charged particles

hurtling toward Earth and interfere with satellite communications,
GPS systems and even airline controls.

Geomagnetic forces have been known to occasionally garble the
world's modern gadgetry, and warnings were issued as recently as

last week when a moderate solar flare sent a coronal mass ejection
in the Earth's direction.

The temperature change associated with any reduction in sunspot
activity would likely be minimal and may not be enough to offset

the impact of greenhouse gases on global warming, according to
scientists who have published recent papers on the topic.

"Recent solar 11-year cycles are associated empirically with
changes in global surface temperature of 0.1 Celsius," said Judith

Lean, a solar physicist with the US Naval Research Laboratory.

If the cycle were to stop or slow down, the small fluctuation in
temperature would do the same, eliminating the slightly cooler
effect of a solar minimum compared to the warmer solar maximum. The

phenomenon was witnessed during the descending phase of the last
solar cycle.

This "cancelled part of the greenhouse gas warming of the period
2000-2008, causing the net global surface temperature to remain

approximately flat -- and leading to the big debate of why the
earth hadn't (been) warming in the past decade," Lean, who was not
involved in the three studies presented, said in an email to AFP.

A study in the March 2010 issue of Geophysical Research Letters

explored what effect an extended solar minimum might have, and
found no more than a 0.3 Celsius dip by 2100 compared to normal
solar fluctuations.

"A new Maunder-type solar activity minimum cannot offset the global

warming caused by human greenhouse gas emissions," wrote authors
Georg Feulner and Stefan Rahmstorf, noting that forecasts by the
Intergovernmental Panel on Climate Change have found a range of 3.7
Celsius to 4.5 Celsius rise by this century's end compared to the

latter half of the 20th century.

"Moreover, any offset of global warming due to a grand minimum of
solar activity would be merely a temporary effect, since the
distinct solar minima during the last millennium typically lasted

for only several decades or a century at most."
_______________________________________________

David J. Ring, Jr., N1EA <http://www.qsl.net/n1ea/>
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