Sunspot cycle update

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NOAA today released its monthly update of the solar cycle, showing the Sun’s sunspot activity in May. It is annotated and posted below.

Mayl 2016 Solar Cycle graph

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

Though sunspot activity increased in May, the increase was not significant. The ramp down from solar maximum continues to track the 2007 low prediction for this maximum.

Meanwhile, the Sun continues its first multi-day string of blank days since 2011, now up to 3 days with all indications suggesting it will continue at least one more day. This early blank string, combined with the relatively fast decline in sunspots in the past two years, suggests that the solar maximum is ending sooner than predicted by the 2009 prediction (the red curve above), and that the next minimum will possibly be longer as well.


  • LocalFluff

    It takes about a month for the Sun to make a rotation. Even though there are a couple of satellites orbitin the Sun, I think the sun spot number is published once a month, since long tradition for comparability, each time the Sun has turned around as seen from Earth. It might be blanc on its current face towards us, but still have 20 sopts on its current far side.

  • “I think the sun spot number is published once a month.”

    No, this is incorrect. They publish a sunspot number each day. It is also based only on the sunspots on the hemisphere of the Sun that faces us, since this has been the standard since they began counting sunspots in the 1600s. Though we have spacecraft now that can see sunspots on the hemisphere away from us, they do not use them for counting purposes so as to keep their system consistent.

  • Garry

    This is the type of issue that comes up not only in science, but in other fields as well, and has frustrated me in various jobs as a leader trying to maintain and/or establish local systems: finding a balance between keeping consistency with the legacy standard, and adopting a new standard that’s obviously more complete or precise.

    I always aim for a hybrid solution: keep the old standard, while establishing the new one as early as possible. In this case, if I were in charge I’d maintain the old count, while establishing a data record of the count of all sunspots on the entire sun, not just the hemisphere facing us. It would be interesting to see the correlations between the 2 systems.

    i’d hate to wake up in 200 years to find that they’re still using the old standard, because they never established the new one.

    Does anyone know of any effort to incorporate the newly available counts?

  • LocalFluff

    But this plot is monthly. Three days in a row without any visible spots means that about 60% of the Sun is spotless. They might just be gathered together right now, even 20 of them, on the far side. The sunspot number is obviously a legacy convention. It does not make a difference between how many spots there are and where they are.

    Anyway, it is low and going down. Few spots, little Solar activity, less protection against cosmic radiation, which might be cloud forming, which reflects sunlight and cools down Earth. No luck for the greehousgassers ahead either after 20 years of stable temperatures inspite of increased CO2-emission. One can predict big politics with this curve! The Sun is the blind spot of the IPCC.

  • Yes, this plot is monthly, but it is also based on the smoothed daily numbers. See the graph on this page, and look especially at the yellow line, which represents the daily number.

  • Edward

    The problem could be more complex than incorporating a hybrid solution. If we go to a hybrid solution and then find a way to transition into a total solar coverage system (what a calibration challenge that would be), what happens when we find that we have lost the satellite on the far side and no replacement is available for a few years.

    Solar weather is not the only place where this can be a problem. We have experienced this with terrestrial weather satellites, when we did not have replacement satellites ready for launch when active satellites were lost from service. A couple of decades ago, meteorologists went from seven-day forecasts to three-day forecasts for a while, until a couple of replacement satellites could be put in place. The US even got Japan to reposition one of their weather satellites, for a while, to help cover the Pacific for forecasting data, until a NOAA replacement satellite got on orbit.

    Getting reliability from temperature data for climate-change observations has similar problems. Ground based thermometers get relocated or the terrain around them changes, changing their environments and making temperature comparisons between current and historical data unreliable.

    It would be a shame if we accidentally did the same to our solar data.

    The newly available counts may not be as important as they may seem, as we do not have a way to make reliable predictions from the traditionally available number of sunspots. Missing a few each month does not yet seem to adversely affect our understanding and may lose whatever importance we place upon the knowledge that there are currently no sunspots on the near side.

    The major advantage of having a satellite observing the sun’s far side is not so much for counting sunspots as it is to increase the data that we have for the behaviors of the sun’s surface, magnetic fields, and corona.

    From Earth-based observation, we are limited in the number of phenomena that we can watch from birth to death — limited to those whose entire lives exist while they are on the near side. With additional observers on the far side, we get more observation time and more complete data.

    I once worked in the Solar Astrophysics Laboratory of a company, and a new company boss suggested that maybe they didn’t need a lab that just counted sunspots. The scientists had to explain what they really did — and that they made money for the company by doing it. Solar astrophysicists are working on understanding how the sun works so that we can better understand and predict how and why its inner workings affect us.

  • TimArth

    Good points everyone. Each time that Bob posts these, I have wondered if they are counting the sunspots on the entire surface of the sun, or if it is only what is facing us. I felt like it was a stupid question, so I never asked, but it is great to have that answered now. I also assumed that even if they were counting only the sunspots on the face which was facing the earth, that statistically, sun spot quantities from “our” face vs. the “far” face probably were approximately (+/-10%) equal. I think it would be quite useful if they would take these measurements of the far face solely so we could at least know if it is approximately equal or not.

  • wayne

    Yes, very enlightening. No clue myself, if we were “counting them all,” or what exactly.

    Interesting Nasa/ESA website-

    Solar & Heliospheric Observatory
    >All things Sun & space-weather related.

  • Garry

    Thanks for the great info, Edward; it puts things into perspective.

    My idea is not necessarily to replace the legacy standard with the new one, but to track both and see correlations with each other, with space weather, global temperatures, etc. Even if there aren’t resources to analyze in depth, at least catalog the data.

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