Astronomical School’s Report, 2019, Volume 15, Issue 1, Pages 1–6
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UDC 523.98

The forecast of solar activity in the 25th and 26th cycles using Excel 2016

Vidmachenko A.P.1, 2

1The Main astronomical observatory of the NAS of Ukraine, 03143, Academician Zabolotny str., 27, Kyiv, Ukraine
2National University of Life and Environmental Sciences of Ukraine, 03041, Heroyiv Oborony st., 15, Kyiv, Ukraine


Climate variations have a significant impact on the development of life processes on Earth. The Sun is the main source of energy in the climate system of our planet. Therefore, for climate prediction, it is important to predict variations in solar activity. When forecasting, the analysis of time series allows, assuming that the trend does not change, to show what should happen in the absence of external interventions. Using the database on the change in the average annual values of the Wolf numbers W(t) from 1700, we in Excel 2016 determined the general trend of changes, and from spectral analysis using the Fourier transform were determined fluctuations around the trend with periods of about 11, 22, 50–60 and 100–111 years old. From the analysis of data W(t) for the years 1700–2018 we calculated the forecast for the change in the Wolf numbers for 2019–2045; and from the data about the activity index in 1913-2018 the forecast of solar activity (SA) for 2019–2040 was calculated. Considering the differences in historical trends for the previous, respectively, 318 and 105 years, in both cases, the forecast for the 25th and 26th cycles of the SA showed less intensity at maximums than the same indicators even for the low-active cycle 24. We note that the use for the forecast only the data for the 1900s, having the greatest activity in the last 300 years, give predictive values 10–15% more than when to add to the historical data observations from 1700. Such addition of data on SA for the previous 200 years, when carrying out forecast calculations, lowers the general forecast trend of changes in Wolf numbers for 2019–2040 in the maxima of the 25th and 26th cycles by 10–15%. This conclusion confirms need to use for predictive calculations as long as possible set of observational data, when the length of the series significantly exceeds the forecast period. It is possible to substantiate the conclusion that the next few 11-year CA cycles should be even less intense than the 24th which ends now. That is, in the coming decades, we can expect a decrease in SA to the extent that was observed, for example, at the end of the 17th century. Therefore, it is possible that at the absence of anthropogenic factors, we are waiting for the next minor ice age. And in the coming years, the trend of increasing the average annual temperature may change to the trend of its decrease.

Keywords: solar activity; forecast; solar-atmospheric relations


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