scholarly journals Analysis of Geomagnetically Induced Currents (GIC) at Equatorial Region over Solar Cycle 24

2021 ◽  
Vol 19 (OCT2021) ◽  
pp. 38-42
Author(s):  
Zatul Iffah Abd Latiff ◽  
Mohamad Huzaimy Jusoh
Keyword(s):  
Solar Cycle ◽  
Equatorial Region ◽  
Geomagnetically Induced Currents ◽  
Solar Cycle 24 ◽  
Induced Currents ◽  
Cycle 24

MAG-GIC: Geomagnetically Induced Currents risk hazard in the Portuguese power network

2020 ◽  
Author(s):  
Joana Alves Ribeiro ◽  
Maria Alexandra Pais ◽  
Fernando J. G. Pinheiro ◽  
Fernando A. Monteiro Santos ◽  
Pedro Soares
Keyword(s):  
Solar Cycle ◽  
Geomagnetic Storms ◽  
Power Network ◽  
The South ◽  
Geomagnetically Induced Currents ◽  
Crust And Upper Mantle ◽  
Solar Cycle 24 ◽  
Induced Currents ◽  
Cycle 24 ◽  
Shunt Reactors

<p>The MAG-GIC project has as a main goal to produce the chart of Geomagnetically Induced Currents (GIC) risk hazard in the distribution power network of Portugal mainland.</p><p>The study of GICs is important as they represent a threat for infrastructures such as power grids, pipelines, telecommunication cables, and railway systems. A deeper insight into GICs hazard may help in planning and designing more resilient transmission systems and help with criteria for equipment selection.</p><p>GICs are a result of variations in the ionospheric and magnetospheric electric currents, that cause changes in the Earth's magnetic field. The Coimbra magnetic observatory (COI) is one of the oldest observatories in operation in the world and the only one in Portugal mainland. It has been (almost) continuously monitoring the geomagnetic field variations since 1866, and in particular, it has registered the imprint of geomagnetic storms during solar cycle 24. Besides the geomagnetic storm signal, which represents the GICs driver, the crust and upper mantle electrical conductivities determine the amplitude and geometry of the induced electric fields.</p><p>To present a better approximation of the Earth's conductivity structure below the Portuguese power network, we initiated a campaign to acquire magnetotelluric (MT) data in a grid of 50x50 km all over the territory. Nonetheless, there already exist enough MT data to create a realistic 3D conductivity model in the south of Portugal.</p><p>The other important input is the electric circuit for the network grid. We benefit from the collaboration of the Portuguese high voltage power network (REN) company, in providing the grid parameters as resistances and transformer locations, thus allowing us to construct a more precise model. In particular, we implement in our model the effect of shield wires and shunt reactors resistances.</p><p>In this study, we present the results of GIC calculations for the south of Portugal for some of the strongest geomagnetic storms in the 20015-17 period recorded at COI during solar cycle 24. We will focus on the sensitivity of results concerning two different conductivity models and different values of the shielding circuit parameters and shunt reactors devices.</p>

Investigation of the possibility of GIC development in Greece during the strongest magnetic storms of solar cycle 24 

2021 ◽  
Author(s):  
Adamantia Zoe Boutsi ◽  
Georgios Balasis ◽  
Ioannis A. Daglis ◽  
Kanaris Tsinganos ◽  
Omiros Giannakis
Keyword(s):  
Solar Cycle ◽  
Magnetic Storms ◽  
Geoelectric Field ◽  
Storm Events ◽  
Power Networks ◽  
Geomagnetically Induced Currents ◽  
Middle Latitudes ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Index Value

<p>Geomagnetically Induced Currents (GIC) constitute an integral part of the space weather research and a subject of ever-growing attention for countries located in the low and middle latitudes. A series of recent studies highlights the importance of considering GIC risks for the Mediterranean region. Here, we exploit data from the HellENIc GeoMagnetic Array (ENIGMA), which is located in Greece, complemented by magnetic observatories in Italy, to calculate corresponding values of the GIC index, i.e., a proxy of the geoelectric field calculated entirely from geomagnetic field variations. We perform our analysis for the most intense magnetic storms (Dst<-150 nT) of solar cycle 24. Our results show a good correlation between the storm sudden commencement (SSC) and an increase of the GIC index value. These investigations indicate that despite the elevated amplitude of the GIC index the associated risk remains at low level for the power networks in Greece and Italy during the considered storm events.</p>

scholarly journals Occurrence of blanketing E<sub>s</sub> layer (E<sub>sb</sub>) over the equatorial region during the peculiar minimum of solar cycle 24

2014 ◽  
Vol 32 (5) ◽  
pp. 553-562 ◽  
Author(s):  
V. Yadav ◽  
B. Kakad ◽  
C. K. Nayak ◽  
G. Surve ◽  
K. Emperumel
Keyword(s):  
Solar Cycle ◽  
Close Association ◽  
Equatorial Electrojet ◽  
Equatorial Region ◽  
Ambient Conditions ◽  
Equatorial Station ◽  
Vernal Equinox ◽  
Solar Cycle 24 ◽  
Sporadic E ◽  
Cycle 24

Abstract. A thin and highly dense sporadic E layer, which can occasionally block the upper ionospheric layers, is called blanketing sporadic E (Esb). We present the statistical seasonal local time occurrence pattern of Esb at equatorial station Tirunelveli (8.7° N, 77.8° E, dip latitude 0.7° N) during the extended minimum of solar cycle 24 (2007–2009). In spite of nearly the same average solar activity during both 2007 and 2009, considerable differences are noticed in the seasonal occurrence of Esb during this period. The percentage of Esb occurrence is found to be the highest during the summer solstice (&amp;geq; 50%) for both 2007 and 2009, which is in general accordance with the earlier studies. The occurrences of Esb during the vernal equinox (~ 33%) and January–February (~ 28%) are substantial in 2009 as compared to those during the same seasons in 2007. We find that, during winter (January–February), ~ 75% of Esb occurred during or just after the period of sudden stratospheric warming (SSW). We suggest that enhanced Esb occurrence during winter (January–February) and the vernal equinox of 2009 could be associated with SSW-driven changes in the E region ambient conditions. Furthermore, the close association of Esb with counter equatorial electrojet (CEEJ) suggested by earlier studies is re-examined carefully using the scenario of Esb occurrence on non-CEEJ days. Such an exercise is crucial as we are unaware whether the physical mechanisms driving Esb and CEEJ are linked or not. We find that, of all the seasons, the association of Esb and CEEJ is strongest during winter (November–December).

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.

Empirical Relationship Between CME Parameters and Geo-effectiveness of Halo CMEs in the Rising Phase of Solar Cycle 24 (2011 – 2013)

Solar Physics ◽  
2015 ◽  
Vol 290 (5) ◽  
pp. 1417-1427 ◽  
Author(s):  
A. Shanmugaraju ◽  
M. Syed Ibrahim ◽  
Y.-J. Moon ◽  
A. Mujiber Rahman ◽  
S. Umapathy
Keyword(s):  
Solar Cycle ◽  
Empirical Relationship ◽  
Solar Cycle 24 ◽  
Halo Cmes ◽  
Cycle 24
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