Fast changes between the solar seasons resolved by new sun clock

Posted: August 18, 2021 by oldbrew in Analysis, Cycles, predictions, research, solar system dynamics
Tags: ,

Sun_NS

Our magnetic Sun [image credit: space.com]

The declining phase of the current solar cycle 25 is predicted to be short. Whether that would follow a low peak remains to be seen, but not much has happened so far in the cycle.
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Violent activity on our Sun leads to some of the most extreme space weather events on Earth, impacting systems such as satellites, communications systems, power distribution and aviation, says Phys.org.

The roughly 11-year cycle of solar activity has three ‘seasons’, each of which affects the space weather felt at Earth differently: (i) solar maximum, the sun is active and disordered, when space weather is stormy and events are irregular (ii) the declining phase, when the sun and solar wind becomes ordered, and space weather is more moderate and (iii) solar minimum, when activity is quiet.

In a new study led by the University of Warwick and published in The Astrophysical Journal, scientists found that the change from solar maximum to the declining phase is fast, happening within a few (27 day) solar rotations.

They also showed that the declining phase is twice as long in even-numbered solar cycles as it is in odd-numbered cycles.

No two solar cycles are the same in amplitude or duration. To study the solar seasons, the scientists built a sun clock from the daily sunspot number record available since 1818. This maps the irregular solar cycles onto a regular clock.

The magnetic polarity of the sun reverses after each roughly 11 year solar cycle giving a roughly 22 year magnetic cycle (named after George Ellery Hale) and to explore this, a 22 year clock was constructed.

The effect on space weather at earth can be tracked back using the longest continuous records of geomagnetic activity over the past 150 years, and once the clock is constructed, it can be used to study multiple observations of seasonal solar activity which affect the earth.

With the greater detail afforded by the sun clock, the scientists could see that the switch from solar maximum to the declining phase is fast, occurring within a few (27 day) solar rotations.

There was also a clear difference in the duration of the declining phase when the sun’s magnetic polarity is ‘up’ compared to ‘down’: in even-numbered cycles it is around twice as long as odd-numbered cycles.

As we are about to enter cycle 25, the scientists anticipate that the next declining phase will be short.

Full article here.

Comments
  1. oldbrew says:

    As we are about to enter cycle 25

    We entered it well over a year ago (Dec. 2019).
    https://en.wikipedia.org/wiki/Solar_cycle_25

    Source: https://www.spaceweather.com/archive.php?view=1&day=03&month=08&year=2021

  2. oldbrew says:

    Solar radio flux is under-performing even the 5% prediction. Today’s reading is 73.
    https://spaceweather.com/archive.php?view=1&day=18&month=08&year=2021

    NASA: ‘best estimate value stated as a 50 percentile value’ [green].
    https://www.nasa.gov/msfcsolar

  3. ichor0 says:

    re “The roughly 11-year cycle of solar activity … There was also a clear difference in the duration of the declining phase … in even-numbered cycles it is around twice as long as odd-numbered cycles.”

    I can’t help but drift to planetary explanations. Jupiter’s orbital period is 11.86 ; Saturn is 29.44. one has to go full Miles Mathis I guess to explain how if it is not the sun all by its lonesome, it could possibly not matter which side of the Sun Saturn it on [for the suns magnetic field to flip]. yet at the same time which side determines the duration of the declining phase.

    no opinion here,. except that conventional ‘double dynamo’ solar model I would guess is totally heuristic (aka ad hoc).

  4. […] Fast changes between the solar seasons resolved by new sun clock […]

  5. oldbrew says:

    The sunspot number forecast.

  6. oldbrew says:

    Sea ice loss during the first half of August stalled, though ice in the Beaufort Sea is finally starting to weaken. The Northern Sea Route appears closed off in 2021, despite being open each summer since 2008.

    As of August 17, sea ice extent stood at 5.77 million square kilometers (2.23 million square miles), tracking above the last six years, as well as 2011, 2012, and 2007 (Figure 1a).

    http://nsidc.org/arcticseaicenews/2021/08/on-the-home-stretch/
    – – –
    No net downward trend in summer sea ice since 2007?

    tracking above the last six years — El Niño effects from 2015-16 wearing off as La Niña takes over?

  7. oldbrew says:

    Nothing going on with the latest solar flux forecast.

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