scholarly journals The Effect of Sunspots Number on Critical frequencies foF2 For the Ionospheric Layer-F2 Over Kirkuk City During the Ascending Phase of Solar Cycle 24

2021 ◽  
Vol 16 (3) ◽  
pp. 19-27
Elaf Bakr ◽  
Wafaa Zaki ◽  
jawdet Mohammed
2021 ◽  
Vol 19 (8) ◽  
pp. 157-168
Wafaa H.A. Zaki

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.

2014 ◽  
Vol 4 (2) ◽  
pp. 477-483
Debojyoti Halder

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.

Solar Physics ◽  
2015 ◽  
Vol 290 (5) ◽  
pp. 1417-1427 ◽  
A. Shanmugaraju ◽  
M. Syed Ibrahim ◽  
Y.-J. Moon ◽  
A. Mujiber Rahman ◽  
S. Umapathy

Space Weather ◽  
2017 ◽  
Vol 15 (12) ◽  
pp. 1649-1660 ◽  
E. M. B. Thiemann ◽  
M. Dominique ◽  
M. D. Pilinski ◽  
F. G. Eparvier

Sign in / Sign up

Export Citation Format

Share Document