General properties of the 24th sunspot cycle and comparison with some other sunspot cycles
Kizilov K.R.
Physics instructors
The study of solar activity has several purposes. The first is to recognize the Sun as a star from an astrophysical point of view, the second is to try to understand the effects of these active events on the world, and the third is to predict what kind of damage solar activity may cause in the near space environment, especially on satellite technologies, in the space age. In this respect, it is very important to follow the Sun closely [1,2]. In this study, the 24th sunspot cycle was compared with the previous 5 cycles in terms of both relative number and spot areas. The cycle started with a value of R=2.2 in December-2008 according to the ISN (13-month adjusted averages). The cycle showed two maximums in both the monthly averages and the adjusted monthly averages. The second maximum is slightly higher than the first. This is the first time such a situation has been encountered. The monthly average relative number reached the first maximum with a value of R=141 in the 33rd month of the cycle. In other words, it took 2.75 years for the cycle to reach the first maximum. The first maximum in SILSO adjusted data was ISN=98 in March-2012. There is a 6-month difference between the monthly averages and the adjusted averages. Monthly averages reached the first maximum earlier. The cycle reached its second maximum 25 months after the first, at the 58th month (4.8 years), in October-2013 with a value of R=147. The second maximum in SILSO data is ISN=116 in April-2014. A double maximum is also seen in the monthly averages of the total areas. Areas reached the first maximum with 1903 µsh at 35 months (2.92 years) and a second maximum at 2252 µsh at 62 months. The second maximum is 18% more severe than the first. The number of spotless days was 265 in 2008 and 262 in 2009. In 2018, 208 days passed without a spot. It is also the most spotless cycle of the last hundred years, with 844 spotless days from December-2008, when the cycle started, to August 5, 2019. The 24th cycle also has the feature of having the lowest maximum relative number value of the last 10 cycles since the 14th cycle (started in January-1902 ). Considering the sunspot area data, he concluded that the 24th cycle was ~20% weaker than the 23rd cycle [3,4].
Figure 1. Monthly average data of “SILSO” and “Observe the sun” for the 24th cycle and between them correlation coefficient. (blue - “SILSO”, red - “Observe the sun”)
In the study, it was concluded that the last six cycles were the cycles with the lowest activity in the cycles we compared, based on our findings of relative number and stain area comparisons. In order to see the compatibility of SILSO and “Observe the sun” data, the sunspot numbers of the cycle we examined were compared. In Figure 1, “SILSO” and “Observe the sun” data from the beginning of the cycle from December-2008 to August-2019 were plotted on the same graph and a very high correlation of 0.98 was found between the two data. This shows us that “Observe the sun” data can be trusted.
References
Bray, R.J., Loughhead, R.E. Sunspots, Dover, New York. 1964
Hanslmeirer, A. The Earth’s Atmosphere and Climate, The Sun and Space Weather, In: Burton, W. B. (ed), Chapter 5, Springer, The Netherland. 2007
http://solarscience.msfc.nasa.gov/predict.shtml
http://www.sidc.be/silso/yearlyssnplot
