scholarly journals Lessons learned from predictions of Solar Cycle 24

2020 ◽  
Vol 10 ◽  
pp. 60
Author(s):  
W. Dean Pesnell
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Coronal Mass Ejections ◽  
Sunspot Cycle ◽  
Lessons Learned ◽  
Machine Learning Techniques ◽  
Polar Regions ◽  
The Sun ◽  
Solar Cycle 24 ◽  
Cycle 24

Solar Cycle 24 has almost faded and the activity of Solar Cycle 25 is appearing. We have learned much about predicting solar activity in Solar Cycle 24, especially with the data provided by SDO and STEREO. Many advances have come in the short-term predictions of solar flares and coronal mass ejections, which have benefited from applying machine learning techniques to the new data. The arrival times of coronal mass ejections is a mid-range prediction whose accuracy has been improving, mostly due to a steady flow of data from SoHO, STEREO, and SDO. Longer term (greater than a year) predictions of solar activity have benefited from helioseismic studies of the plasma flows in the Sun. While these studies have complicated the dynamo models by introducing more complex internal flow patterns, the models should become more robust with the added information. But predictions made long before a sunspot cycle begins still rely on precursors. The success of some categories of the predictions of Solar Cycle 24 will be examined. The predictions in successful categories should be emphasized in future work. The SODA polar field precursor method, which has accurately predicted the last three cycles, is shown for Solar Cycle 25. Shape functions for the sunspot number and F10.7 are presented. What type of data is needed to better understand the polar regions of the Sun, the source of the most accurate precursor of long-term solar activity, will be discussed.

Regression Analysis of Sunspot Numbers for the Solar Cycle 24 in Comparison to Previous Three Cycles

2014 ◽  
Vol 4 (2) ◽  
pp. 477-483
Author(s):  
Debojyoti Halder
Keyword(s):  
Regression Analysis ◽  
Solar Cycle ◽  
Sunspot Number ◽  
The Sun ◽  
Sunspot Numbers ◽  
Solar Cycle 24 ◽  
Current Cycle ◽  
Cycle 24

Sunspots are temporary phenomena on the photosphere of the Sun which appear visibly as dark spots compared to surrounding regions. Sunspot populations usually rise fast but fall more slowly when observed for any particular solar cycle. The sunspot numbers for the current cycle 24 and the previous three cycles have been plotted for duration of first four years for each of them. It appears that the value of peak sunspot number for solar cycle 24 is smaller than the three preceding cycles. When regression analysis is made it exhibits a trend of slow rising phase of the cycle 24 compared to previous three cycles. Our analysis further shows that cycle 24 is approaching to a longer-period but with smaller occurrences of sunspot number.

scholarly journals MANIFESTATION OF SOLAR ACTIVITY AND DYNAMICS OF THE ATMOSPHERE IN VARIATIONS OF 577.7 AND 630.0 nm ATMOSPHERIC EMISSIONS IN SOLAR CYCLE 24

2020 ◽  
Vol 6 (3) ◽  
pp. 81-85
Author(s):  
Aleksandr Mikhalev
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Atomic Oxygen ◽  
Correlation Coefficients ◽  
Atmospheric Emissions ◽  
Annual Average ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Activity Indices

In the paper, variations of the night emission intensities in the 557.7 and 630 nm atomic oxygen lines [OI] in 2011–2019 have been analyzed. The analysis is based on data from the ISTP SB RAS Geophysical Observatory. The emission intensities are compared with atmospheric, solar, and geophysical parameters. High correlation coefficients between monthly average and annual average 630.0 nm emission intensities and solar activity indices F10.7 have been obtained. This suggests a key role of solar activity in variations of this emission in the period of interest. Variations of the 557.7 nm emission demonstrate to a greater extent the correlations of the stratospheric zonal wind (QBO.U30 index) with quasi-biennial oscillations. The causes of the weak dependence of the 557.7 nm emission intensity on solar activity in solar cycle 24 are discussed.

Seasonal behavior of H component during solar cycle 24

2021 ◽  
Author(s):  
Yasmina Bouderba ◽  
Ener Aganou ◽  
Abdenaceur Lemgharbi
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Horizontal Component ◽  
Low Latitude ◽  
Seasonal Behavior ◽  
The Earth ◽  
Earth Magnetic Field ◽  
Solar Cycle 24 ◽  
Minimum Solar Activity ◽  
Cycle 24

<p>In this work we will show the behavior of the horizontal component H of the Earth Magnetic Field (EMF) along the seasons during the period of solar cycle 24 lasting from 2009 to 2019. By means of  continuous measurements of geomagnetic components (X, Y) of the EMF, we compute the horizontal component H at the Earth’s surface. The data are recorded with a time resolution of one minute at Tamanrasset observatory in Algeria at the geographical coordinates of 22.79° North and 5.53° East. These data are available from the INTERMAGNET network. We find that the variation in amplitude of the hourly average of H component at low latitude changes from a season to another and it is greater at the maximum solar activity than at the minimum solar activity.</p><p><strong>Keywords:</strong> Solar cycle 24, Season, Horizontal component H. </p>

The Impact of Sunspots Number on Critical Frequencies foF2 for the IONOSPHERIC Layer-F2 Over Erbil Station During the Down Phase of Solar Cycle 24

2021 ◽  
Vol 19 (8) ◽  
pp. 157-168
Author(s):  
Wafaa H.A. Zaki
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Sunspot Number ◽  
Critical Frequency ◽  
Radio Communication ◽  
Ionospheric Layer ◽  
Solar Cycle 24 ◽  
Critical Frequency Fof2 ◽  
Cycle 24 ◽  
The Impact

The ionosphere layer (F2) is known as the most important layer for High frequency (Hf) radio communication because it is a permanent layer and excited during the day and night so it is able to reflect the frequencies at night and day due to its high critical frequency, and this layer is affected by daily and monthly solar activity. In this study the characteristics and behavior of F2 layer during Solar cycle 24 were studied, the effect of Sunspots number (Ri) on the critical frequency (foF2), were investigated for the years (2015, 2016, 2017, 2018, 2019, 2020) which represents the down phase of the solar cycle 24 over Erbil station (36° N, 44° E) by finding the critical frequency (foF2) values, the layer’ s impression times are determined for the days of solstice as well as equinox, where the solar activity was examined for the days of the winter and summer solstice and the days of the spring and autumn equinoxes for a period of 24 hours by applied the International Reference Ionosphere model IRI (2016). The output data for foF2 were verified by using the IRI-Ne- Quick option by specifying the time, date and Sunspot number parameters. Statistical analysis was caried out through the application of the Minitab (version 2018) in order to find the correlation between the critical frequency (foF2) of Ionospheric layer F2 and Sunspot number. It was concluded that the correlation is strong and positive, this indicate that critical frequency (foF2) increase with increasing Sunspots number (Ri) for solar cycle 24.

X-Ray Flares and Activity Complexes on the Sun in Solar Cycle 24

2020 ◽  
Vol 64 (1) ◽  
pp. 58-65 ◽  
Author(s):  
E. S. Isaeva ◽  
V. M. Tomozov ◽  
S. A. Yazev
Keyword(s):  
Solar Cycle ◽  
The Sun ◽  
X Ray ◽  
Solar Cycle 24 ◽  
Cycle 24

Synoptic maps in three wavelengths of the Chromospheric Telescope

2018 ◽  
Vol 14 (A30) ◽  
pp. 339-341
Author(s):  
Andrea Diercke ◽  
Carsten Denker
Keyword(s):  
Time Series ◽  
Solar Cycle ◽  
Solar Disk ◽  
The Sun ◽  
Observational Period ◽  
Quiet Sun ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Spectral Ranges ◽  
Full Disk

Abstracthe Chromospheric Telescope (ChroTel) observes the entire solar disk since 2011 in three different chromospheric wavelengths: Hα, Ca ii K, and He i. The instrument records full-disk images of the Sun every three minutes in these different spectral ranges. The ChroTel observations cover the rising and decaying phase of solar cycle 24. We started analyzing the ChroTel time-series and created synoptic maps of the entire observational period in all three wavelength bands. The maps will be used to analyze the poleward migration of quiet-Sun filaments in solar cycle 24.

scholarly journals Seasonal Variations of the Optimum Reliable Frequencies During Maximum and Minimum Periods of Solar Cycle 24

2020 ◽  
Vol 31 (4) ◽  
pp. 15
Author(s):  
Samar Abdalkaream Thabit ◽  
Loay E. George ◽  
Khalid A. Hadi
Keyword(s):  
Mathematical Model ◽  
Solar Activity ◽  
Solar Cycle ◽  
Seasonal Variations ◽  
Path Length ◽  
Polynomial Equation ◽  
Ionospheric Parameter ◽  
Solar Cycle 24 ◽  
Path Lengths ◽  
Cycle 24

In this research, the seasonal Optimal Reliable Frequency (ORF) variations between different transmitter/receiver stations have been determined. Mosul, Baghdad, and Basra have been chosen as tested transmitting stations that located in the northern, center, and southern of Iraqi zone. In this research, the minimum and maximum years (2009 and 2014) of solar cycle 24 have been chosen to examine the effect of solar activity on the determined seasonal ORF parameter. Mathematical model has been proposed which leads to generate the Optimal Reliable Frequency that can maintain the seasonal connection links for different path lengths and bearings. The suggested ORF parameter represented by a different orders polynomial equation. The polynomial equation has been determined depending on different selected parameters (path length, bearing, time (day), months and BUF values). The suggested seasonal ORF parameter was examined for the three stations of the adopted years. The value of the seasonal ORF ionospheric parameter increased with the increase of path length and varies with the bearing between the transmitting and receiving stations also, the seasonal ORF values were higher at maximum solar cycle (2014) than the minimum solar cycle (2009).

scholarly journals Coronal mass ejections and sunspot number over solar cycle 24

2021 ◽  
Vol 10 (6) ◽  
Author(s):  
Preetam Singh Gour ◽  
Shiva Anon ◽  
Devangana Shyamlan Chaturvedi
Keyword(s):  
Solar Cycle ◽  
Sunspot Number ◽  
Coronal Mass Ejections ◽  
Solar Cycle 24 ◽  
Cycle 24

scholarly journals Predicting amplitude of solar cycle 24 based on a new precursor method

2010 ◽  
Vol 28 (2) ◽  
pp. 417-425 ◽  
Author(s):  
A. Yoshida ◽  
H. Yamagishi
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Solar Minimum ◽  
Physical Phenomenon ◽  
Late Phase ◽  
The Sun ◽  
Precursor Method ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
The Imf

Abstract. It is shown that the monthly smoothed sunspot number (SSN) or its rate of decrease during the final years of a solar cycle is correlated with the amplitude of the succeeding cycle. Based on this relationship, the amplitude of solar cycle 24 is predicted to be 84.5±23.9, assuming that the monthly smoothed SSN reached its minimum in December 2008. It is further shown that the monthly SSN in the three-year period from 2006 through 2008 is well correlated with the monthly average of the intensity of the interplanetary magnetic field (IMF). This correlation indicates that the SSN in the final years of a solar cycle is a good proxy for the IMF, which is understood to reflect the magnetic field in the corona of the sun, and the IMF is expected to be smallest at the solar minimum. We believe that this finding illuminates a physical meaning underlying the well-known precursor method for forecasting the amplitude of the next solar cycle using the aa index at the solar minimum or its average value in the decaying phase of the solar cycle (e.g. Ohl, 1966), since it is known that the geomagnetic disturbance depends strongly on the intensity of the IMF. That is, the old empirical method is considered to be based on the fact that the intensity of the coronal magnetic field decreases in the late phase of a solar cycle in parallel with the SSN. It seems that the precursor method proposed by Schatten et al. (1978) and Svalgaard et al. (2005), which uses the intensity of the polar magnetic field of the sun several years before a solar minimum, is also based on the same physical phenomenon, but seen from a different angle.

Sign in / Sign up

Export Citation Format

Share Document