scholarly journals A Qualitative Study of the Ionospheric Weak Response to Super Geomagnetic Storms

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 635
Author(s):  
Haimeng Li ◽  
Zhou Chen ◽  
Lianqi Xie ◽  
Fan Li
Keyword(s):  
Geomagnetic Storm ◽  
Geomagnetic Storms ◽  
Processing Method ◽  
Statistical Characteristics ◽  
High Solar Activity ◽  
Storm Event ◽  
Time Interval ◽  
Weak Response ◽  
Ionospheric Response ◽  
Middle Latitudes

The ionospheric response to a geomagnetic storm is a geophysical process. Although strong geomagnetic storms input more energy into the Earth’s upper atmosphere, the ionospheric response often does not reflect the same level of variation as the geomagnetic storm, and the response may be weak during a very strong storm. However, the estimated ionospheric response to geomagnetic activity also varies with extraction method. Here, two different methods—the spectral whitening method (SWM) and the monthly median method (MMM)—are used to verify whether the apparent weak ionospheric response is an artifact of the processing method. The weak ionospheric response is found with both methods, which suggests it is a real ionospheric phenomenon. The statistical characteristics of the regional and global ionospheric weak response to a super geomagnetic storm (SGS) and to an SGS with a preceding storm event (SGS-PRE) are investigated and compared. The results show that the regional ionospheric weak response to an SGS is more prevalent at middle latitudes than those at low and high latitudes. The global ionospheric weak response occurs more frequently under high solar activity and has a strong correlation with SGS-PRE, which suggests that the effect of a storm on the ionosphere can be influenced by its preconditioning, especially when there is an earlier storm and the time interval between the two storms is short. In fact, an ionospheric long-lasting disturbance may be an important reason for the ionospheric weak response caused by the SGS-PRE.

scholarly journals Unexpected Southern Hemisphere ionospheric response to geomagnetic storm of 15 August 2015

2018 ◽  
Vol 36 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Ilya Edemskiy ◽  
Jan Lastovicka ◽  
Dalia Buresova ◽  
John Bosco Habarulema ◽  
Ivan Nepomnyashchikh
Keyword(s):  
South Africa ◽  
Southern Hemisphere ◽  
Geomagnetic Storms ◽  
Geomagnetic Latitude ◽  
Electron Content ◽  
Solar Activity Minimum ◽  
Total Electron ◽  
Ionospheric Response ◽  
Middle Latitudes ◽  
Local Noon

Abstract. Geomagnetic storms are the most pronounced phenomenon of space weather. When studying ionospheric response to a storm of 15 August 2015, an unexpected phenomenon was observed at higher middle latitudes of the Southern Hemisphere. This phenomenon was a localized total electron content (TEC) enhancement (LTE) in the form of two separated plumes, which peaked southward of South Africa. The plumes were first observed at 05:00 UT near the southwestern coast of Australia. The southern plume was associated with local time slightly after noontime (1–2 h after local noon). The plumes moved with the Sun. They peaked near 13:00 UT southward of South Africa. The southern plume kept constant geomagnetic latitude (63–64° S); it persisted for about 10 h, whereas the northern plume persisted for about 2 h more. Both plumes disappeared over the South Atlantic Ocean. No similar LTE event was observed during the prolonged solar activity minimum period of 2006–2009. In 2012–2016 we detected altogether 26 LTEs and all of them were associated with the southward excursion of Bz. The negative Bz excursion is a necessary but not sufficient condition for the LTE occurrence as during some geomagnetic storms associated with negative Bz excursions the LTE events did not appear.

scholarly journals Accuracy of Global Ionosphere Maps in Relation to Their Time Interval

2021 ◽  
Vol 13 (18) ◽  
pp. 3552
Author(s):  
Beata Milanowska ◽  
Paweł Wielgosz ◽  
Anna Krypiak-Gregorczyk ◽  
Wojciech Jarmołowski
Keyword(s):  
Solar Activity ◽  
Geomagnetic Storms ◽  
High Solar Activity ◽  
Time Interval ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Low Latitudes ◽  
Globally Distributed ◽  
Gnss Observations

Global ionosphere maps (GIMs) representing ionospheric total electron content (TEC) are applicable in many scientific and engineering applications. However, the GIMs provided by seven Ionosphere Associated Analysis Centers (IAACs) are generated with different temporal resolutions and using different modeling techniques. In this study, we focused on the influence of map time interval on the empirical accuracy of these ionospheric products. We investigated performance of the high-resolution GIMs during high (2014) and low (2018) solar activity periods as well as under geomagnetic storms (19 February 2014 and 17 March 2015). In each of the analyzed periods, GIMs were also assessed over different geomagnetic latitudes. For the evaluation, we used direct comparison of GIM-derived slant TEC (STEC) with dual-frequency GNSS observations obtained from 18 globally distributed stations. In order to perform a comprehensive study, we also evaluated GIMs with respect to altimetry-derived vertical TEC (VTEC) obtained from the Jason-2 and Jason-3 satellites. The study confirmed the influence of GIMs time interval on the provided TEC accuracy, which was particularly evident during high solar activity, geomagnetic storms, and also at low latitudes. The results show that 120-min interval contributes significantly to the accuracy degradation, whereas 60-min one is sufficient to maintain TEC accuracy.

scholarly journals Role of neutral wind and storm time electric fields inferred from the storm time ionization distribution at low latitudes: in-situ measurements by Indian satellite SROSS-C2

2005 ◽  
Vol 23 (10) ◽  
pp. 3289-3299 ◽  
Author(s):  
P. Subrahmanyam ◽  
A. R. Jain ◽  
L. Singh ◽  
S. C. Garg
Keyword(s):  
Geomagnetic Storm ◽  
Electric Fields ◽  
Geomagnetic Storms ◽  
Activity Period ◽  
High Solar Activity ◽  
Satellite Network ◽  
Neutral Winds ◽  
Weather Events ◽  
Low Latitudes ◽  
Time Changes

Abstract. Recently, there has been a renewal of interest in the study of the effects of solar weather events on the ionization redistribution and irregularity generation. The observed changes at low and equatorial latitudes are rather complex and are noted to be a function of location, the time of the storm onset and its intensity, and various other characteristics of the geomagnetic storms triggered by solar weather events. At these latitudes, the effects of geomagnetic storms are basically due to (a) direct penetration of the magnetospheric electric fields to low latitudes, (b) development of disturbance dynamo, (c) changes in atmospheric neutral winds at ionospheric level and (d) changes in neutral composition triggered by the storm time atmospheric heating. In the present study an attempt is made to further understand some of the observed storm time effects in terms of storm time changes in zonal electric fields and meridional neutral winds. For this purpose, observations made by the Retarding Potential Analyzer (RPA) payload on board the Indian satellite SROSS-C2 are examined for four prominent geomagnetic storm events that occurred during the high solar activity period of 1997-2000. Available simultaneous observations, from the GPS satellite network, are also used. The daytime passes of SROSS-C2 have been selected to examine the redistribution of ionization in the equatorial ionization anomaly (EIA) region. In general, EIA is observed to be weakened 12-24 h after the main phase onset (MPO) of the storm. The storm time behaviour inferred by SROSS-C2 and the GPS satellite network during the geomagnetic storm of 13 November 1998, for which simultaneous observations are available, is found to be consistent. Storm time changes in the delay of received GPS signals are noted to be ~1-3 m, which is a significant component of the total delay observed on a quiet day. An attempt is made to identify and delineate the effects of a) meridional neutral winds, b) the development of the ring currents and c) the disturbance dynamo electric fields on the low latitude ionization distribution. The weakening of the EIA is noted to be primarily due to the decrease in the eastward electric fields driving the equatorial fountain during the daytime. The meridional neutral winds are also noted to play an important role in redistribution of ionization in the EIA region. The present results demonstrate that storm time latitudinal distribution of ionization in this region can be better understood by taking into account the meridional winds in addition to E×B drifts.

scholarly journals Daytime electron density at the F1-region in Europe during geomagnetic storms

2002 ◽  
Vol 20 (7) ◽  
pp. 1007-1021 ◽  
Author(s):  
D. Buresova ◽  
J. Lastovicka ◽  
D. Altadill ◽  
G. Miro
Keyword(s):  
Solar Activity ◽  
Electron Density ◽  
Geomagnetic Storm ◽  
Geomagnetic Storms ◽  
Middle Latitude ◽  
Lower Latitude ◽  
Ionospheric Disturbances ◽  
Activity Levels ◽  
Middle Latitudes

Abstract. This study attempts to demonstrate changes in the ionospheric F1-region daytime ionization during geomagnetic storms. The F1-region is explored using available data from several European middle latitude and lower latitude observatories and a set of geomagnetic storms encompassing a range of seasons and solar activity levels. The results of analysis suggest systematic seasonal and partly latitudinal differences in the F1-region response to geomagnetic storm. The pattern of the response of the F1-region at higher middle latitudes, a decrease in electron density, does not depend on the type of response of the F2-region and on solar activity. A brief interpretation of these findings is presented.Key words. Ionosphere (ionospheric disturbances; mid-latitude ionosphere)

A Fuzzy Logic Approach to Evaluate Transformer Fleet Risk From Geomagnetic Storms

2016 ◽  
Author(s):  
Sujit Purushothaman
Keyword(s):  
Fuzzy Logic ◽  
Geomagnetic Storm ◽  
Geomagnetic Storms ◽  
Geomagnetic Latitude ◽  
Geomagnetic Disturbance ◽  
Specific Factor ◽  
Storm Event ◽  
Geoelectric Field ◽  
Fuzzy Logic Approach ◽  
Specific Factors

This paper presents a simple approach to evaluate risk to transformer units from geomagnetic storms. A simple fuzzy logic based approach was used to develop the model which is capable of categorizing transformers in a fleet into three risk categories, i.e., high, medium and low. This model may be used as a first screening step to evaluate a fleet of transformers without conducting time consuming simulations and studies. Critical factors that affect geomagnetically induced current (GIC) flow are used as input parameters to the model. These factors include location-specific, equipment-specific and geomagnetic storm event-specific factors. Location-specific factors include geomagnetic latitude of the location, earth conductivity structure at location and distance of location from coast. Equipment-specific factors include transformer rating and age. The storm event-specific factor of geoelectric field strength was used which is an indication of the return period of the geomagnetic disturbance event. The paper describes the implementation of this model to evaluate fleet risk for a 1 in 100 year event and the Carrington event (largest recorded geomagnetic storm in history). The fuzzy logic membership functions for the inputs are described in detail and the performance of the fuzzy logic model is evaluated.

scholarly journals MODEL BADAI IONOSFER INDONESIA TERKAIT BADAI GEOMAGNET (INDONESIA IONOSPHERIC STORM MODEL RELATED TO GEOMAGNETIC STORM)

2018 ◽  
Vol 15 (1) ◽  
pp. 25
Author(s):  
Anwar Santoso ◽  
Mira Juangsih ◽  
Sri Ekawati ◽  
Iyus Edi Rusnadi ◽  
Anton Winarko ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Geomagnetic Storms ◽  
Weather Conditions ◽  
Space Science ◽  
Ionospheric Storm ◽  
Science Center ◽  
Ionospheric Response ◽  
Future Space ◽  
Ap Index ◽  
Storm Model

 Knowledge about the ionospheric response to the geomagnetic storms is needed to support SWIFtS activity in Space Science Center-LAPAN. However, it is difficult to predict its behavior. As an approach, it needs a model of the ionospheric response to geomagnetic storms. In this paper, the modeling of the Indonesia ionospheric storms to the geomagnetic storm was done by modifying the global empirical models developed by Araujo-Pradere. By using ap index data, Dst index, and foF2 ionosphere from BPAA Sumedang of 2005-2015, it was obtained the Indonesia ionospheric storms model related to the geomagnetic storm. The analysis result showed that the Sumedang ionospheric storms model had a deviation or error < 40% of the data. Therefore it can be concluded that this models can be used to support the SWIFtS activity in Space Science Center-LAPAN for future space weather conditions.  AbstrakPengetahuan tentang respon ionosfer terhadap badai geomagnet sangat diperlukan untuk mendukung kegiatan SWIFtS di Pusat Sains Antariksa-LAPAN. Namun, sulit diprediksi perilakunya. Sebagai pendekatan, diperlukan sebuah model respon ionosfer terhadap badai geomagnet. Dalam makalah ini, dilakukan pemodelan badai ionosfer Indonesia terkait badai geomagnet dengan memodifikasi model empiris global yang telah dikembangkan oleh Araujo-Pradere. Dengan menggunakan data indeks ap, indeks Dst dan foF2 ionosfer BPAA Sumedang tahun 2005-2015 diperoleh model badai ionosfer regional Indonesia terhadap badai geomagnet. Dari analisis disimpulkan bahwa model badai ionosfer Sumedang tersebut memiliki simpangan atau kesalahan < 40% terhadap data. Hal ini menunjukkan bahwa model badai ionosfer Sumedang tersebut dapat dipergunakan untuk mendukung kegiatan SWIFtS di Pusat Sains Antariksa-LAPAN sebagai bahan pertimbangan dalam memprediksi kondisi cuaca antariksa akan datang.   

scholarly journals Some theoretical of ionospheric storms at middle latitudes

1998 ◽  
Vol 41 (4) ◽  
Author(s):  
G. A. Mansilla ◽  
J. R. Manzano
Keyword(s):  
Numerical Method ◽  
Electron Density ◽  
Geomagnetic Storm ◽  
Continuity Equation ◽  
Geomagnetic Storms ◽  
Neutral Wind ◽  
Wind Effects ◽  
Middle Latitudes ◽  
Maximum Electron Density ◽  
Density Values

Neutral wind effects in the F2-region during geomagnetic storms are theoretically studied solving the continuity equation (with production and loss of electrons) by means of a numerical method. This study was made for storms with sudden commencement at different times of day and at different latitudes. The results show that the equatorward movements of neutral air produce either enhanced or depressed maximum electron density values which depend on the velocity of these winds when the perturbation occurs at diurnal hours. If the geomagnetic storm is present during the night, only enhanced values are observed.

scholarly journals Measurement of geomagnetically induced current (GIC) around Tokyo, Japan

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Shinichi Watari ◽  
Satoko Nakamura ◽  
Yusuke Ebihara
Keyword(s):  
Solar Flare ◽  
Geomagnetic Storms ◽  
Power Grids ◽  
Geomagnetic Variation ◽  
Induced Current ◽  
Interplanetary Shocks ◽  
Geomagnetic Disturbances ◽  
Geomagnetically Induced Current ◽  
Middle Latitudes ◽  
Sudden Commencements

AbstractWe need a typical method of directly measuring geomagnetically induced current (GIC) to compare data for estimating a potential risk of power grids caused by GIC. Here, we overview GIC measurement systems that have appeared in published papers, note necessary requirements, report on our equipment, and show several examples of our measurements in substations around Tokyo, Japan. Although they are located at middle latitudes, GICs associated with various geomagnetic disturbances are observed, such as storm sudden commencements (SSCs) or sudden impulses (SIs) caused by interplanetary shocks, geomagnetic storms including a storm caused by abrupt southward turning of strong interplanetary magnetic field (IMF) associated with a magnetic cloud, bay disturbances caused by high-latitude aurora activities, and geomagnetic variation caused by a solar flare called the solar flare effect (SFE). All these results suggest that GIC at middle latitudes is sensitive to the magnetospheric current (the magnetopause current, the ring current, and the field-aligned current) and also the ionospheric current.

scholarly journals Ionosonde Observations of Spread F and Spread Es at Low and Middle Latitudes during the Recovery Phase of the 7–9 September 2017 Geomagnetic Storm

2021 ◽  
Vol 13 (5) ◽  
pp. 1010
Author(s):  
Lehui Wei ◽  
Chunhua Jiang ◽  
Yaogai Hu ◽  
Ercha Aa ◽  
Wengeng Huang ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Large Scale ◽  
Satellite System ◽  
Recovery Phase ◽  
Ionospheric Irregularities ◽  
Middle Latitudes ◽  
Multiple Observations ◽  
Swarm Satellites ◽  
Spread F ◽  
Global Navigation Satellite

This study presents observations of nighttime spread F/ionospheric irregularities and spread Es at low and middle latitudes in the South East Asia longitude of China sectors during the recovery phase of the 7–9 September 2017 geomagnetic storm. In this study, multiple observations, including a chain of three ionosondes located about the longitude of 100°E, Swarm satellites, and Global Navigation Satellite System (GNSS) ROTI maps, were used to study the development process and evolution characteristics of the nighttime spread F/ionospheric irregularities at low and middle latitudes. Interestingly, spread F and intense spread Es were simultaneously observed by three ionosondes during the recovery phase. Moreover, associated ionospheric irregularities could be observed by Swarm satellites and ground-based GNSS ionospheric TEC. Nighttime spread F and spread Es at low and middle latitudes might be due to multiple off-vertical reflection echoes from the large-scale tilts in the bottom ionosphere. In addition, we found that the periods of the disturbance ionosphere are ~1 h at ZHY station, ~1.5 h at LSH station and ~1 h at PUR station, respectively. It suggested that the large-scale tilts in the bottom ionosphere might be produced by LSTIDs (Large scale Traveling Ionospheric Disturbances), which might be induced by the high-latitude energy inputs during the recovery phase of this storm. Furthermore, the associated ionospheric irregularities observed by satellites and ground-based GNSS receivers might be caused by the local electric field induced by LSTIDs.

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