Solar Cycle 25 may have shown signs of life of late, but all is once again quite on the earth-facing solar disc -- Solar Minimum vs GSM
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SOLAR MINIMUM AIN’T OVER YET
JUNE 18, 2020 CAP ALLON
Solar Cycle 25 may have shown signs of life of late, but all is once again quite on the earth-facing solar disc.
During the past month, Solar Cycle 25 has produced the
strongest solar flare in three years (M1-class), as well as a sunspot that lasted for two whole weeks (AR2765) that then erupted on June 9th:
Dark magnetic filament bisecting sunspot AR2765 erupting on June 9th at 1800 UT
However, the Sun is once again blank and quiet, points out Dr Tony Phillips at
spaceweather.com. This is a sign that, while Solar Minimum may be loosening its grip, it ain’t over yet.
SOLAR MINIMUMS VS GSMS
The difference between
Solar Minimums and
GRAND Solar Minimums is causing some confusion out there.
The
former refers to the weakest part of a standard 11-or-so year solar cycle, or the ‘trough’.
Using the Radio Flux chart below, we can see the minimum of Solar Cycle 24 began in 2018 and is still running today. Also visible is the minimum from the previous Solar Cycle 23 which began in 2008 and ended in 2010:
Just like the sunspot count, the solar radio flux at 10.7 cm (2800 MHz) is an excellent indicator of solar activity. Here it shows the peak and trough of solar activity through one 11 year cycle (cycle 24) — the cycle began in 2010, the peak in 2014, and the trough in 2018.
And if anyone knows why NOAA are discontinuing this useful tool from July 1st, please let me know — my spidey senses are tingling.
Whereas the
latter, a GRAND Solar Minimum, refers to a run of MULTIPLE 11-or-so year solar cycles where the Sun’s output is consistently weak, where our star is often devoid of sunspots for decades at a time:
Yearly Sunspot Numbers.
Grand Solar Minimums can last for 100+ years in some cases, as was true with the
Spörer Minimum (1450-1560):
Historic Grand Solar Minimums.
The most recent and probably most infamous GSM was the
Maunder Minimum which ran from
1645-1715. Our Modern “Eddy” Grand Solar Minimum
that we’re entering now will most-likely run for a similar duration — around 70 years
(though theories are numerous, and it’s really anyone’s guess).
During the
Maunder, “temperatures across much of the Northern Hemisphere plunged,” say
NASA. “Europe and North America went into a deep freeze: alpine glaciers extended over valley farmland; sea ice crept south from the Arctic; and the famous canals in the Netherlands froze regularly—an event that is rare today.”
Along with GRAND Solar Minimums, there are also multidecadal periods of low solar activity that don’t quite cut it as their grander counterparts.
The most recent examples of these include the
Centennial (or Glassberg/Gleissberg) Minimum (1880-1914), and the
Dalton Minimum (1796-1820).
Like the
deeper Maunder and Spörer Minimums preceding it, the
Dalton brought on a period of lower-than-average global temperatures. The Oberlach Station in Germany, for example, experienced a 2C decline over 20 years, which devastated the country’s food production.
‘The Year Without a Summer’ also occurred during the
Dalton Minimum, in 1816. It was caused by a combination of already low temperatures plus the aftereffects of the second largest volcanic eruption of the past 2000 years — Mount Tambora’s VEI 7 on April 10, 1815.
These periods of solar-driven cooling are cyclic.
History repeats.
Unfortunately for us, the Modern Grand Solar MAXIMUM has run its course, and the COLD TIMES are returning in line with
historically low solar activity,
cloud-nucleating Cosmic Rays, and a
meridional jet stream flow.
Even NASA agrees, if you read between the lines, with their forecast for this upcoming solar cycle
(25) seeing it as “
the weakest of the past 200 years,” with the agency correlating previous solar shutdowns to prolonged periods of global cooling
here.
Prepare accordingly —
learn the facts, relocate if need be, and grow your own.