scholarly journals South Atlantic Anomalyduring ascending and maximum phase of solar cycle 24

2020 ◽  
Author(s):  
Khairul Afifi Nasuddin ◽  
Mardina Abdullah ◽  
Nurul Shazana Abdul Hamid

Abstract. For this research, four regions have been studied which are the South Atlantic Anomaly (SAA) region, low latitude region, middle latitude region and high latitude region. The active period which is the period when the geomagnetic storm occur chosen to be analyzed is on 6 August 2011 and 12 April 2014 and the normal period, a period when no geomagnetic storm happen is on 24 July 2011 and 14 May 2014. Year 2011 is chosen to be analyze in order to study the SAA region during the ascending phase of the solar cycle 24 and in year 2014, where the occurrence of the maximum phase of solar cycle 24 occur. The research is carried since there is no clear characterization of the SAA during ascending as well as maximum phase based on power spectrum analysis method. The Earth's magnetic field component chosen to be analyzed is the horizontal intensity (H) due to its sensitiveness regarding geomagnetic activeness. From the research conducted, the result reveal SAA region has a tendency to be persistent during both period compare to other region during both phases. Other regions in the research experience a tendency to be persistent and antipersistent.

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.


2018 ◽  
Author(s):  
Khairul Afifi Nasuddin ◽  
Mardina Abdullah ◽  
Nurul Shazana Abdul Hamid

Abstract. This research intends to characterize the South Atlantic Anomaly (SAA) by applying power spectrum analysis approach. From the approach, the Hurst exponent can be determined. The motivation to study the SAA region is due to its nature. A comparison was made between the stations in the SAA region and outside the SAA region during the geomagnetic storm occurrence (active period) and normal period where no geomagnetic storm occurred. The data for the occurrence of the active period was taken on 11 March 2011 while for normal period on 3 February 2011. The outcomes of the research revealed that the SAA region had a tendency to be persistent during active period and normal periods. It can be said, it experiences this characteristic because of the Earth’s magnetic field strength. Through the research, it is found that as the Earth magnetic field increases, it is likely to show an antipersistent value. This is found in the high latitude region. The lower the Earth magnetic field, the more it shows the persistent value as in the middle latitude region. In the region where the Earth magnetic field is very low like the SAA region it shows a tendency to be persistent.


2019 ◽  
Vol 26 (1) ◽  
pp. 25-35
Author(s):  
Khairul Afifi Nasuddin ◽  
Mardina Abdullah ◽  
Nurul Shazana Abdul Hamid

Abstract. This research intends to characterize the South Atlantic Anomaly (SAA) by applying the power spectrum analysis approach. The motivation to study the SAA region is due to its nature. A comparison was made between the stations in the SAA region and outside the SAA region during the geomagnetic storm occurrence (active period) and the normal period where no geomagnetic storm occurred. The horizontal component of the data of the Earth's magnetic field for the occurrence of the active period was taken on 11 March 2011 while for the normal period it was taken on 3 February 2011. The data sample rate used is 1 min. The outcome of the research revealed that the SAA region had a tendency to be persistent during both periods. It can be said that the region experiences these characteristics because of the Earth's magnetic field strength. Through the research, it is found that as the Earth's magnetic field increases, it is likely to show an antipersistent value. This is found in the high-latitude region. The lower the Earth's magnetic field, the more it shows the persistent value as in the middle latitude region. In the region where the Earth's magnetic field is very low like the SAA region it shows a tendency to be persistent.


2021 ◽  
Author(s):  
Prithvi Raj Singh ◽  
A. I. Saad Farid ◽  
Y. P. Singh ◽  
A. K. Singh ◽  
Ayman A. Aly

Abstract To study the solar rotational oscillation on daily averaged time series of solar activity proxies: sunspot number (SSN), modified coronal index (MCI), solar flare index (FI), and cosmic ray intensity (CRI) are subjected to Lomb/Scargle periodogram, and continuous wavelet transform. For this purpose, we have used data of all the considered parameters from 2012 to 2015, which covers the maximum phase including the polarity reversal period of the solar cycle 24. Both spectral analysis techniques are carried out to study the behavior of 27-days on the time scale of the synodic period and to follow their evolution throughout the epoch. Further, we have used R package RobPer (least square regression) techniques and obtained a significant true period ~27 days is present in this study. It is noted that the ~27-day period of solar activity parameters and cosmic rays is much prominent during the examined period.


Solar Physics ◽  
2020 ◽  
Vol 295 (10) ◽  
Author(s):  
Agnieszka Gil ◽  
Renata Modzelewska ◽  
Szczepan Moskwa ◽  
Agnieszka Siluszyk ◽  
Marek Siluszyk ◽  
...  

Abstract During Solar Cycle 24, which started at the end of 2008, the Sun was calm, and there were not many spectacular geoeffective events. In this article, we analyze the geomagnetic storm that happened on 15 July 2012 during the 602nd anniversary of the Polish Battle of Grunwald, thus we propose this event to be called the “Battle of Grunwald Day Storm”. According to NOAA scale, it was a G3 geomagnetic storm with a southward component of the heliospheric magnetic field, $Bz$ B z , falling to −20 nT, minimum Dst index of −139 nT, AE index of 1368 nT, and Ap index of 132 nT. It was preceded by a solar flare class X1.4 on 12 July. This geomagnetic storm was associated with the fast halo coronal mass ejection at 16:48:05 UT on 12 July, first appearance in the Large Angle and Spectroscopic Coronagraph C2, with a plane-of-sky speed of 885 km s−1 and maximum of 1415 km s−1. This geomagnetic storm was classified as the fourth strongest geomagnetic storm of Solar Cycle 24. At that time, a significant growth in the failures of the Polish electric transmission lines was observed, which could have a solar origin.


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