Category Archives: Solar Flux

Sunspot Number History Change Is Underway

For those readers of this blog that follow the monthly update of Solar Cycle 24, things are about to change. For the better I think, but until the final report is 400yrsofsunspotcyclesUnknownreleased, we wont know for sure. Sunspot Index and Long-term Solar Observations (SILSO) a part of the World Data Center has issued a Sunspot Bulletin that says:”

                                           Warning of Major Data Change

Over the past 4 years a community effort has been carried out to revise entirely the historical sunspot number series. A good overview of the analyses and identified corrections is provided in the recent review paper: Clette, F., Svalgaard, L., Vaquero, J.M., Cliver, E. W.,”Revisiting the Sunspot Number. A 400-Year Perspective on the Solar Cycle”, Space Science Reviews, Volume 186, Issue 1-4, pp. 35-103.

Now that the new data series has been finalized, we are about to replace the original version of our sunspot data by an entirely new data set on July 1st. On this occasion, we decided to simultaneously introduce changes in several conventions in the data themselves and also in the distributed data files.

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Solar Cycle 24 May 15 Update–Belated

Updating Solar Cycle 24 May 2015 status indicates that despite an uptick in Sunspots, the trend is still moving away from the maximum to quieter times.


The May International Sunspot number was 58.8 versus April’s number of 54.4. (Click on charts to enlarge.)


The F10.7cm solar flux number, perhaps the best indicator of solar activity, can be seen on this chart:

solar-cycle-10-cm-radio-fluxMAY15NOAAThe F10.7cm is comparable to the Sunspots chart in magnitude and direction.

The following chart shows data through the 14th of June.  Cycle 24 is still a long way from minimum (estimated to be in 2019 by NASA, although my guess is it will be at least a year more) and that can be seen by the NOAA Sunspot number that shot up about one week into the month of June.


Skeptic Reference Sources–Part 1

There are several excellent sources for Skeptics. This posting provides a the sunsource for Solar Research Papers.   The amount of Sun based research may surprise you, because the Warmers continue to tell us that the Sun is not important.

Some of the research is readily available and some is behind paywalls. But I suspect that just looking at the available research will occupy you for some long time.   The source is Club du Soleil  Click here to see  this source.

There are several additional resources that I will post soon.


Solar Cycle 24 Activity Continues To Decline

The April 2015 Solar Cycle 24 Sunspot number rose somewhat in April, but the forecast is for a continued decline in activity.   The 2015 monthly Sunspot counts were: January = 67.0, February=44.8, March=38.4 and April=54.4.   The daily Sunspot counts seesawed, but definitely with a downward trend, Ri(black).  This can be seen be examining Rsouth (green). While Rnorth has been reasonably quiet for a year or so, Rsouth has been the major contributor to the total number since late 2013.

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Predicting Solar Cycle 25. Are We Heading For Another Maunder Minimum?

A study was published in 2012, Sudden transitions and grand variations in the solar dynamo, past and future” by Cornelis DeJager and Silvia Duhan . The authors attempt to predict whether Solar Cycle 25 will transition to a “Grand Minimum” or “Regular “ Episode. They believe the Sun is transitioning from a “Grand Maximum” to one or the other aforementioned Episodes. This study is being used because their prediction was based upon knowing the Solar Cycle 24’s maximum Sunspot number which we now have.

First a look at the “Episodes” that the authors have placed the Solar Cycles from 1620 to the present.

grandcyclesswsc120009-fig4The diagram shows the sunspot numbers plotted against time. The three Grand Episodes are marked by their different colors. They are separated by vertical black lines.

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Cycle 24-November ’14—Sunspot Number Trend

Cycle 24 solar activity looked liked it had peaked somewhere around March of 2011 at about 68. But it hadn’t.   The smoothed International Sunspot (SS) number is currently around 82 around as shown by the dashed blue line on this chart:

cycle24-2More detail can be seen on the following chart where the activity in November is up from October. Both SS and solar flux (F10.7 cm) peaked at about 170 in November.


Solar Cycle 24 is still much less active than Solar Cycle 23 as can be seen in the chart below:

sunspotscycles23_24 nov14

The green line is the predicted path of the smoothed International SS number.  This time the turn down in solar activity  may actually be the “maximum” for Solar Cycle 24.

An El Nino is happening now. It should continue into next year. Early indications were that it would be very weak, but it has picked up some strength. This event is likely to have an effect and may even break the run of more than 18-year pause in global temperatures. Solar Cycle 24’s low solar activity might offset the El Nino with the “pause’ continuing. Nobody knows.

Probably the most comprehensive discussions of the what and where-fore of an El Nino are by Bob Tisdale postings. Clicking here will direct you to his postings.












Early look at Solar Cycle 24 July Activity

Since late last year, Solar Cycle 24 has picked up activity as it goes through a double peak maximum.   I doubt that is an official term but it does describe what has been going on. It was generally though that the peak International Smoothed Sunspot number for Cycle 24 was going to be about 66.   But the recent activity will result in a smoothed peak number of 81 or there about.  (Click on charts for clarity.)


This chart of approximately the last 12 months, shows that F-10.7cm solar flux and Sunspot numbers are closely aligned, both being good proxies for solar activity.

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