scholarly journals Looking for Changes in Photospheric Temperature Gradients over Solar Cycle 24 Using Hinode/SP

Author(s):  
James Crowley
2014 ◽  
Vol 4 (2) ◽  
pp. 477-483
Author(s):  
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 ◽  
Author(s):  
A. Shanmugaraju ◽  
M. Syed Ibrahim ◽  
Y.-J. Moon ◽  
A. Mujiber Rahman ◽  
S. Umapathy

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

2017 ◽  
Vol 44 (21) ◽  
Author(s):  
Robin Ramstad ◽  
Stas Barabash ◽  
Yoshifumi Futaana ◽  
Masatoshi Yamauchi ◽  
Hans Nilsson ◽  
...  

2021 ◽  
pp. 3759-3771
Author(s):  
Ja'far M. Ja’far ◽  
Khalid A. Hadi

        In this research, an investigation for the compatibility of the IRI-2016 and ASAPS international models was conducted to evaluate their accuracy in predicting the ionospheric critical frequency parameter (foF2) for the years 2009 and 2014 that represent the minimum and maximum years of solar cycle 24. The calculations of the monthly average foF2 values were performed for three different selected stations distributed over the mid-latitude region. These stations are Athens - Greece (23.7o E, 37.9 o N), El Arenosillo - Spain (-6.78 o E, 37.09 o N), and Je Ju - South Korea (124.53 o E, 33.6 o N). The calculated values using the two tested models were compared with the observed foF2 datasets for each of the three selected locations. The results showed that the two tested models gave good and close results for all selected stations compared to the observed data for the studied period of time. At the minimum solar cycle 24, the ASAPS model showed in general better values than the IRI-2016 model at Athens, El Arenosillo and Je Ju stations for all tested methods. At maximum solar cycle 24, the IRI-2016 model showed higher and closer values to the observed data at Athens and El Arenosillo stations, while the ASAPS model showed better values at Je Ju station.


Sign in / Sign up

Export Citation Format

Share Document