[W8MWA] ARRL website article indicates some encouraging news on Solar Cycle 24-25

[Spence Graham]

12/30/2019

New Solar Cycle 25 is on the way, but just when the transition from Cycle
24 to Cycle 25 will take place is not entirely clear. On December 24, two
new sunspots — one in each hemisphere — emerged on the face of the sun that
exhibit the reversed magnetic polarity marking them as belonging to Solar
Cycle 25. According to *Hale’s Law*
<https://www2.hao.ucar.edu/Education/Sun/hales-sunspot-polarity-law>,
sunspot polarities flip-flop from one solar cycle to the next, the National
Center for Atmospheric Research explains.

“The sun is currently in solar minimum — the nadir of the 11-year sunspot
cycle,” Tony Phillips said in his article, “*Reversed Polarity Sunspots
Appear on the Sun*
<https://spaceweatherarchive.com/2019/12/25/reversed-polarity-sunspots-appear-on-the-sun/>”
on the Spaceweather.com website. “It’s a deep minimum, century-class
according to sunspot counts.” The remarkable sunspot scarcity has prompted
discussion of a possible “extended minimum” akin to the Maunder Minimum in
the 17th century, when no sunspots appeared for decades, Phillips said.
“Such an event could have implications for terrestrial climate.”

“Today’s new-cycle sunspots (along with isolated new-cycle spots earlier
this year) suggest that the solar cycle is, in fact, unfolding normally,”
Phillips wrote, adding that a new Maunder Minimum does *not* appear to be
in the offing.

Earlier this month, the NOAA/NASA-co-chaired international Solar Cycle
Prediction Panel released its *latest forecast*
<http://www.swpc.noaa.gov/news/solar-cycle-25-forecast-update> for Solar
Cycle 25. The panel’s consensus calls for a peak in July 2025 (±8 months),
with a smoothed sunspot number of 115 and the solar minimum between Cycles
24 and 25 occurring in April 2020 (±6 months). If this solar minimum
prediction is correct, it would make Solar Cycle 24 the seventh longest on
record at 11.4 years.

Climate scientist David Archibald speculates that the Solar Cycle 24/25
minimum could occur as late as March 2021, and that Cycle 25 maximum might
not happen until 2027.

“We are well into the Solar Cycle 24/25 minimum but [Cycle] 24 may not have
ended yet,” Archibald said in a December 22 *update*
<https://wattsupwiththat.com/2019/12/22/solar-update-december-2019/> on the
Watts Up With That? website. “A solar cycle isn’t over until the
heliospheric current sheet has flattened. And that could be as late as
March 2021. Solar cycle amplitude does matter with respect to climate and
the amplitude of Solar Cycle 25, from projecting trends from the last three
cycles, looks like being about 80 in 2027.”

The Solar Cycle Prediction Panel agreed that Cycle 25 will be of average
intensity and similar to Cycle 24.

In an *article*
<https://www.swpc.noaa.gov/sites/default/files/images/u4/0620McIntosh.pdf>
posted
on NOAA’s Space Weather Prediction Center site, Scott McIntosh, the
Director of the High Altitude Observatory at National Center for
Atmospheric Research (*NCAR* <https://ncar.ucar.edu/>), stresses that Solar
Cycle 25 will happen, “but a sunspot cycle could be small.”

Predictability comes with some physical understanding of the underlying
process, McIntosh asserts. “The sunspot cycle is erratic,” he said in his
presentation, “provocative of a chaotic, turbulent solar interior where
sunspot progressions with time and latitude are the only tracers…”

-- 
73,

Spence

*Spencer W. Graham, II*
*WT8WV*
*73 Crosby Road*
*Morgantown, WV 26508*

*2017-2019 VP of Monongalia Wireless Association http://www.w8mwa.org/
<http://www.w8mwa.org/> *
*ARRL Volunteer Examiner *
*W5YI Volunteer Examiner*
*Laurel ARC Volunteer Examiner*
*ARRL WV Section Affiliate Club Coordinator *

*Check Out My Ham Radio Blog Site...  http://kb8fir.wordpress.com
<http://kb8fir.wordpress.com>*

*(ex-KB8FIR and ex-KA8LJO)*
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