Solar Activity

Last Updated: 09/02/2022
Sunspot Number: 67
Solar Wind: speed 443.3 km/sec, density: 8.1 protons/cm³,
Solar Wind current density: 3.591×10⁸ proton/cm²/sec
Current Stretch of days without sunspots: 0

Number of Spotless Days by Year:

2022: 1 day so far
2021: 64 days
2020: 208 days
2019: 281 days
2018: 221 days
2017: 104 days
2016: 32 days
2015: 0 days

This page is devoted to keeping track of how active the Sun is, particularly how strong the solar wind might be. In the model of global warming we described in the Global Warming post theme, particularly in the post Clouds and Global Warming, whether or not the Earth is warming depends primarily on the fraction of the Earth’s surface that is covered with clouds. The primary effect of the clouds is to shade and cool the Earth by reflecting back to space incident solar thermal radiation before it can appreciably warm the atmosphere. The fraction of cloud coverage is determined by the amount of ionizing high-energy cosmic ray-charged particles that penetrate the atmosphere. There it ionizes particulates that will act as cloud nucleation centers around which water droplets can condense.

This describes a 70-year cycle of solar activity, with approximately 35 years of warming followed by 35 years of cooling. We have just entered the warming phase of the 70-year cycle. This cycle is superimposed on a much longer cycle of around 50 thousand years. We are currently in the warming phase of that cycle. Others have detected a 1500-year cycle of warming and cooling.

Some time ago (news released August 25, 2016), physicists at the National Space Institute, Technical University of Denmark, and at the Racah Institute of Physics at the Hebrew University of Jerusalem published an analysis of 25 years of satellite observations strengthening the idea that there is a strong link between solar activity, cosmic ray intensity in the atmosphere, and cloud cover. I took that as an excuse to write a post summarizing the model for global warming (Not Anthropogenic Global Warming or AGW!), in which I also embedded two videos of the CERN physicist Jasper Kirkby explaining his CLOUD experiment. That experiment proved that cosmic rays at typical intensities and energies in the atmosphere would ionize typical aerosol particulates with sizes and densities sufficient to serve as cloud nucleation centers. The post is Solar Wind, Cosmic Rays and Clouds: The Determinants of Global Warming.

Additional essays concerning global warming you might find interesting are  The Great Global Warming Scam, a list of prominent scientists opposing AGW together with links to their curriculum vitae; the essay What Consensus on Anthropogenic Global Warming? containing links to videos of interviews, scholarly talks, and congressional testimony of eminent scientists opposing AGW; and the post Anti-AGW Global Warming Scholarly References, a list of a sample of their refereed, scholarly papers that are anti-AGW. A discussion of how measured total solar output power density (Total Solar Irradiance or TSI) fits into the picture can be found in the post More Measurements To Deflate AGW Enthusiasts.

Earth to Sky Calculus is a student group affiliated with Spaceweather.com, which periodically launches weather balloons with instruments for measuring cosmic ray intensity in the stratosphere. It has just published a new graph of stratospheric cosmic ray intensity.  Cosmic ray intensity is plotted in units of microsieverts per hour (uSv/hr), where a microsievert is one-millionth of a Sievert, and a Sievert is a derived unit of ionizing radiation dose. The plot shows the correlation between solar activity and cosmic ray intensities in the stratosphere. Notice the data is consistent with global cooling caused by increasing cloud cover.

The amount of high-energy cosmic rays that penetrate the atmosphere is determined by the strength of the solar wind. It is well known that an intense solar wind can blow cosmic rays away and keep them from penetrating the inner solar system. See Clouds and Global Warming and Solar Power Output and Global Warming. For this reason it would be good to keep track of how active the Sun is to determine if we should expect the current period of global cooling to continue.

The information on this page comes primarily from the Solar Physics page of NASA’s Marshall Space Flight Center. Additional daily data is taken from spaceweather.com. As we determined in Solar Power Output and Global Warming, periods of greater solar activity with higher power output and more intense solar wind are correlated with greater numbers of sunspots on the Sun’s surface. One of the first things you will see on NASA’s Solar Physics page is the graph below.As you can see from it, we have just passed the solar maximum of the 11-year sunspot cycle and the peak sunspot number was roughly half the number in the previous solar maximum, If you were to click on this plot on the NASA page, you would get the series of plots just below our first plot.

Carefully perusing these plots, you will note in the last global warming period between 1975 and 2000, sunspot numbers at the solar maxima increased until about 1990 and then began to become smaller again. This observation would appear to agree with our model. Currently, the sunspot number is predicted to decline at least through 2020.

To determine the sun spot number, use is made of the fact that the average number of sunspots in a closely associated group of them is roughly 10. The sunspot number is then taken to be approximately 10 times the number of sunspot groups plus the number of individual sunspots.

Note in the sunspot scatter plots above that from roughly 1917 to 1947(sunspot cycles 15-18) and between 1970 and 1990 (sunspot cycles 20-22), two periods of global warming in the 20th century, the peaks of the sunspot cycles were generally increasing. Also note between 1947 and 1970 (sunspot cycles18-20) and between 1990 to the present (sunspot cycles 22-24), two periods of warming hiatus or gentle cooling, the peaks of the sunspot were generally decreasing. This observation is consistent with the global warming model in the Global Warming Theme, and summarized in the post Global Warming: A Summation.

There are two “official” series of sunspot numbers: one is the International Sunspot Number maintained by the Solar Influences Data Analysis Center in Belgium; and the NOAA sunspot number compiled by the U.S. National Oceanic and Atmospheric Administration. We will report and record the NOAA data. In the plots below, the sun spot number and the solar wind current density are shown versus time. The sun spot number is an approximate indicator of phase of the solar cycle (high at solar maximum and low at solar minimum). Because of the noisy nature of the data (the sun after all is a turbulent system), I also plot the 30-day moving averages of the sunspot number and the solar wind current density superimposed as heavy orange curves on the plots.

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