Deceptive Sun

courtesy: http://sdo.gsfc.nasa.gov/data/


A quick glance at Sunday's sun reveals a spotless environment, something we will likely be seeing more often in the years to come as the Solar Minimum arrives around 2020. The last minimum in 2009 saw a total of 260 days of spotless suns and long periods of very little geomagnetic activity.


Incredibly, during the minimum in the 28 year period between 1672 and 1699 there were 50 sunspots total. That's not a week or a month but two 11 year cycles worth. The normal expectation would be 40,000 - 50,000 spots within a 28-year period.

But the present, apparently quiet-looking sun, is not all as it appears as a look at today's satellite data and magnetometer readings indicate we are in the midst of a pretty good disturbance, driving the planetary K-index to level 5.

courtesy: http://www.swpc.noaa.gov/
The source of the disturbance, as is often the case when the sun is not flaring, is a coronal hole stream ... CH738 to be precise, rotating into a geoeffective position once again after causing a similar disturbance to our geomagnetic field one month ago on its previous rotation. The large hole is the dark region approaching the right limb.

courtesy: http://sdo.gsfc.nasa.gov/data/
Back in the early 30's when amateurs and professionals were starting to draw links between radio propagation and sunspot activity, there must have been a lot of head-scratching when propagation disturbances arose from apparently quiet-looking suns, similar to what is happening at present.

With the vast array of solar instrumentation available to us online, much of the mystery involving propagation has been removed, making the tracking and even the predicting of geomagnetic activity, very much easier nowadays.

Kiruna Magnetometer: http://www.irf.se/maggraphs/

From my location on the west coast of North America, my main 6m interest over the past several summer seasons has been focused on the short-lived and exciting sporadic-e openings over the pole to Europe ... but today's sun is not helping. Most of these fleeting openings seem to require undisturbed fields in the polar regions ... geomagnetic quiet. Once CH738 rotates out of view, hopefully the polar activity will subside and maybe, just maybe, the magical 6m polar path to Europe will tease us once again.

The July 8th, 2014 magic - West Coast to Europe on 6m
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

6 Responses to “Deceptive Sun”

  • ac7af:

    It looks like we will need sporadic e and aurora for our propagation on the magic band and 10m , I hope this years e will be better than last year we had a good opening around xmas maybe that will dictate this summers e season.

  • Colin GM4JPZ:

    Steve, thanks for posting the article, which I found interesting and informative. I’m sure you are used to the occasional mental CMEs from disturbed individuals, and I know we should just ignore DQRM, but I just had to make a comment on the comment. My father used to tell me that sarcasm was the lowest form of wit, and I have seldom seen a better example of what he meant.
    73!
    Colin

  • Colin GM4JPZ:

    Sorry, AC7AF, your post just beat my comment on K4AGO’s eruption.

  • Steve VE7SL:

    Thanks guys. No problem. Maybe he’ll tell us what it’s like to perfect….73

  • Kd4gnx Richard:

    To all the negatives, the first 3 paragraphs mention nothing about radio propagation. Steve was giving a little history about sun spot activities for that particular time.
    I guess somewhere I missed the “PERFECT” button.
    Now for perfectionists’ out there, however did you all miss the math part of the article?
    I make it as 27 yrs not 28. (And I’m not here to explicitly point that out.

    Steve, good job!
    As I was reading it didn’t occur to me of radios and the “time”, I knew better, and had better things to do until I read the remarks.
    Steve thanks again for a little bit of history.
    73, Richard

  • Steve VE7SL:

    Gius… from the start of 1672 through to the end of 1699 is 28 years, not 27!

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