GPS Phase Scintillation at High Latitudes during Two Geomagnetic Storms

2015 ◽  
pp. 211-231 ◽  
Author(s):  
Paul Prikryl ◽  
Reza Ghoddousi‐Fard ◽  
John M. Ruohoniemi ◽  
Evan G. Thomas
Keyword(s):  
Geomagnetic Storms ◽  
High Latitudes

scholarly journals The geomagnetic cutoff rigidities at high latitudes for different solar wind and geomagnetic conditions

2016 ◽  
Vol 34 (1) ◽  
pp. 45-53 ◽  
Author(s):  
W. Chu ◽  
G. Qin
Keyword(s):  
Solar Wind ◽  
Cosmic Rays ◽  
Strong Correlation ◽  
Geomagnetic Storms ◽  
Dynamic Pressure ◽  
Threshold Value ◽  
High Latitudes ◽  
Dst Index ◽  
Ae Index ◽  
Geomagnetic Cutoff

Abstract. Studying the access of the cosmic rays (CRs) into the magnetosphere is important to understand the coupling between the magnetosphere and the solar wind. In this paper we numerically studied CRs' magnetospheric access with vertical geomagnetic cutoff rigidities using the method proposed by Smart and Shea (1999). By the study of CRs' vertical geomagnetic cutoff rigidities at high latitudes we obtain the CRs' window (CRW) whose boundary is determined when the vertical geomagnetic cutoff rigidities drop to a value lower than a threshold value. Furthermore, we studied the area of CRWs and found out they are sensitive to different parameters, such as the z component of interplanetary magnetic field (IMF), the solar wind dynamic pressure, AE index, and Dst index. It was found that both the AE index and Dst index have a strong correlation with the area of CRWs during strong geomagnetic storms. However, during the medium storms, only AE index has a strong correlation with the area of CRWs, while Dst index has a much weaker correlation with the area of CRWs. This result on the CRW can be used for forecasting the variation of the cosmic rays during the geomagnetic storms.

A UNIFYING THEORY OF HIGH-LATITUDE GEOPHYSICAL PHENOMENA AND GEOMAGNETIC STORMS

1961 ◽  
Vol 39 (10) ◽  
pp. 1433-1464 ◽  
Author(s):  
W. I. Axford ◽  
C. O. Hines
Keyword(s):  
Solar Wind ◽  
Steady State ◽  
High Latitude ◽  
Geomagnetic Storms ◽  
High Latitudes ◽  
Full Understanding ◽  
Earth’S Magnetosphere ◽  
Trapped Particles ◽  
Outer Portion ◽  
Earth's Magnetosphere

This paper is concerned with the occurrence at high latitudes of a large number of geophysical phenomena, including geomagnetic agitation and bay disturbances, aurorae, and various irregular distributions of ionospheric electrons. It shows that these may all be related in a simple way to a single causal agency, namely, a certain convection system in the outer portion of the earth's magnetosphere. The source of this convection is taken to be a viscous-like interaction between the magnetosphere and an assumed solar wind, though other sources of an equivalent nature may also be available. The model is capable of accounting for many aspects of the phenomena concerned, including the morphology of auroral forms and the occurrence of 'spiral' patterns in the loci of maximum intensities of several features. It also bears directly on the steady state of the magnetosphere, and in particular on the production of trapped particles in the outer Van Allen belt. In short, it provides a new basis on which a full understanding of these several phenomena may in time be built.

Studying the Ionospheric Responses Induced by a Geomagnetic Storm in September 2017 with Multiple Observations in America

2020 ◽  
Author(s):  
Yang Liu ◽  
Zheng Li ◽  
Jinling Wang
Keyword(s):  
Electron Density ◽  
Geomagnetic Storm ◽  
Geomagnetic Storms ◽  
Ionospheric Irregularities ◽  
Electron Content ◽  
High Latitudes ◽  
Total Electron ◽  
Multiple Observations ◽  
The Usa ◽  
Plasma Depletions

<p>A series of studies have suggested that a geomagnetic storm can accelerate the formation of plasma depletions and the generation of ionospheric irregularities. Using observation data from the Continuously Operating Reference Stations (CORS) network in the USA, the responses of the ionospheric total electron content (TEC) to the geomagnetic storm on September 8, 2017 are studied in detail. A mid-latitude trough was discovered from 01:00 UT to 06:00 UT in the USA with a length exceeding 5000 km. The probable causes are the combination of a classic negative storm response with increments in the neutral composition and the expansion of the auroral oval, pushing the mid-latitude trough equatorward.  Super-scale plasma depletion was observed by SWARM data accompanied by the expansion of mid-latitude trough. Both PPEF from high latitudes and pole-ward neutral wind are responsible for the large-scale ionospheric irregularities. Medium-scale travelling ionospheric disturbances (MSTID) with wavelengths of 600–700 km were generated accompanied by a drop and perturbation in the electron density. The intensity of the MSTID fluctuations reached over 2.5 TECU, which were discovered by filtering the differential TEC. The evolution of plasma depletions were associated with the MSTID propagating from high latitudes to low latitudes. SWARM spaceborne observations also showed a drop in the electron density from 10<sup>5</sup> to 10<sup>3</sup> compared to the background values at 28° N, 96° W, and 25° N, 95° W. This research investigates super-scale plasma depletions generated by geomagnetic storms using both CORS GNSS and spaceborne observations. The proposed work is valuable for better understanding the evolution of ionospheric depletions during geomagnetic storms.</p>

Evaluation of E-Layer Dominated Ionosphere Events Using CHAMP, COSMIC/FORMOSAT-3 and FY3C Data

2020 ◽  
Author(s):  
Sumon Kamal ◽  
Norbert Jakowski ◽  
Mohammed M. Hoque ◽  
Jens Wickert
Keyword(s):  
Electron Density ◽  
Space Weather ◽  
Geomagnetic Storms ◽  
Weather Conditions ◽  
Polar Regions ◽  
High Latitudes ◽  
Density Profiles ◽  
Temporal Occurrence ◽  
Electron Density Profiles ◽  
Activity Dependent

<p>Under certain space weather conditions the ionization level of the ionospheric E layer can dominate over that of the F2 layer. This phenomenon is known as “E layer dominated ionosphere” (ELDI) and occurs primarily at high latitudes in the polar regions. The corresponding electron density profiles show their peak ionization at the E layer height between 80 km and 150 km above the Earth’s surface. In this work we have evaluated the influence of space weather and geophysical conditions on the occurrence of ELDI events at high latitudes in the northern and southern hemispheres. For this, we used electron density profiles derived from ionospheric radio occultation measurements aboard CHAMP, COSMIC and FY3C satellites. The used CHAMP data covers the years from 2001 to 2008, the COSMIC data the years from 2006 to 2018 and the FY3C data the years from 2014 to 2018. This provides us continuous data coverage for a long period from 2001 to 2018, containing about 4 million electron density profiles. In addition to the geospatial distribution, we have also investigated the temporal occurrence of ELDI events in the form of the diurnal, the seasonal and the solar activity dependent variation. We have further investigated the influence of geomagnetic storms on the spatial and temporal occurrence of ELDI events.</p>

scholarly journals ANALISIS RESPON MEDAN GEOMAGNET ANTARA STASIUN DI EKUATOR MAGNET DAN STASIUN BIAK SAAT BADAI GEOMAGNET PADA MERIDIAN MAGNET 210⁰ MM

2016 ◽  
Vol 13 (2) ◽  
pp. 63
Author(s):  
Anwar Santoso
Keyword(s):  
Response Time ◽  
Geomagnetic Storm ◽  
Geomagnetic Field ◽  
Field Data ◽  
Geomagnetic Storms ◽  
Geomagnetic Disturbance ◽  
Magnetic Equator ◽  
High Latitudes ◽  
Geomagnetic Equator ◽  
Occurrence Probability

Geomagnetic storm is a geomagnetic disturbance that occurs globally. Until now believed that the greatest impact of geomagnetic storms occurred in the high latitudes and decreases with decreasing latitude to the equator. However, based on the data component of the geomagnetic field H obtained CPMN other phenomena, that is H minimum of Onagawa station (31,15o LU; 212,63o BT magnetic coordinates) is smaller than the H minimum at Biak station (9,73o latitude; 207,39o BT magnetic coordinates) during geomagnetic storms on July 15, 2000. This reality is different from what was believed to be on top. To ensure this, then done the analysis of the geomagnetic field H component response based on the latitude using the geomagnetic field data from Biak station and stations around 210o MM for the whole event a strong geomagnetic storms (Dst <-100 nT) during 1995-2001. Results of the analysis showed that the response time of geomagnetic field geomagnetic storm in Biak is greater than at the magnetic equator (YAP) with an difference average of H is 59,27 nT. EEJ and CEJ pattern in the EEJ region (10o S to 10o N magnetic coordinate) shown could effected to the response of geomagnetic geomagnetic. The most important to note that if the geomagnetic response in Indonesia higher than in the geomagnetic equator (YAP) then the occurrence probability of GIC in Indonesia is higher.  AbstrakBadai geomagnet merupakan gangguan geomagnet yang terjadi secara global. Sampai saat ini dipercaya bahwa dampak terbesar badai geomagnet terjadi di lintang tinggi dan semakin menurun dengan menurunnya lintang sampai di ekuator. Namun, berdasarkan olah data komponen H medan geomagnet dari CPMN diperoleh fenomena lain yaitu H minimum dari stasiun Onagawa (31,15⁰ LU; 212,63⁰ BT koordinat magnet) lebih kecil dari H minimum Balai Penjejakan dan Kendali Wahana Antariksa (BPKWA) Biak (9,73⁰ LS; 207,39⁰ BT koordinat magnet) saat badai geomagnet 15 Juli 2000. Kenyataan ini berbeda dari apa yang telah dipercayai di atas. Untuk memastikan hal ini maka dilakukan analisis respon komponen H medan geomagnet berdasarkan lintang menggunakan data komponen H medan geomagnet dari BPKWA Biak dan stasiun di sekitar 210⁰ MM untuk seluruh kejadian badai geomagnet kuat (Dst < -100 nT) selama 1995-2001. Hasil analisis diperoleh bahwa respon medan geomagnet saat badai geomagnet di Biak lebih besar dari pada di ekuator magnet (YAP) dengan rata-rata selisih ∆H-nya 59,27 nT. EEJ dan CEJ di daerah EEJ (10⁰ LU sampai 10⁰ LS magnet) terbukti mempengaruhi respon geomagnet. Hal terpenting yang perlu diperhatikan dari hasil ini adalah bahwa jika respon geomagnet di Indonesia lebih tinggi dibandingkan di daerah ekuator geomagnet (YAP) maka potensi kemunculan GIC juga lebih besar terjadi di Indonesia. 

scholarly journals Impact of magnetic storms on the global TEC distribution

2018 ◽  
Author(s):  
Donat V. Blagoveshchensky ◽  
Olga A. Maltseva ◽  
Maria A. Sergeeva
Keyword(s):  
Satellite Data ◽  
Average Velocity ◽  
Geomagnetic Storms ◽  
Magnetic Activity ◽  
Simultaneous Occurrence ◽  
Seasonal Effect ◽  
Electron Content ◽  
High Latitudes ◽  
Opposite Hemisphere ◽  
Total Electron

Abstract. The study is focused on the analysis of Total Electron Content (TEC) variations during six geomagnetic storms of different intensity: from Dstmin = −46 nT to Dstmin = −223 nT. The values of TEC deviations from its 27-day median value (δTEC) were calculated during the periods of the storms along three meridians: American, Euro-African and Asian-Australian. The following results were obtained. For the majority of the storms almost simultaneous occurrence of δTEC maximums was observed along the Asian-Australian and Euro-African meridians at the beginning of the storm. The transition from weak storm to superstorm (the increase of magnetic activity) almost does not affect the intensity of δTEC maximum. The effect revealed for the American sector during two storms was the movement of the disturbance front from Northern and Southern high latitudes towards the equator with the average velocity of ~ 400 m/s. The seasonal effect was most pronounced at Asian-Australian meridian, less often at Euro-African meridian and was not revealed at American meridian. Sometimes the seasonal effect can penetrate to the opposite hemisphere. The character of averaged δTEC variations for the intense storms was confirmed by GOES satellite data. The behaviour of correlation coefficient (R) between δTEC at three meridians was analyzed for each storm. In general, R > 0.5 between δTEC averaged along each meridian. This result is new. The possible reasons for the exceptions (when R 

scholarly journals GPS phase scintillation at high latitudes during geomagnetic storms of 7–17 March 2012 – Part 2: Interhemispheric comparison

2015 ◽  
Vol 33 (6) ◽  
pp. 657-670 ◽  
Author(s):  
P. Prikryl ◽  
R. Ghoddousi-Fard ◽  
L. Spogli ◽  
C. N. Mitchell ◽  
G. Li ◽  
...  
Keyword(s):  
Solar Wind ◽  
High Latitude ◽  
Geomagnetic Storms ◽  
Companion Paper ◽  
Auroral Oval ◽  
Ionospheric Scintillation ◽  
High Latitudes ◽  
Polar Cap ◽  
Interplanetary Coronal Mass Ejections ◽  
The North

Abstract. During the ascending phase of solar cycle 24, a series of interplanetary coronal mass ejections (ICMEs) in the period 7–17 March 2012 caused geomagnetic storms that strongly affected high-latitude ionosphere in the Northern and Southern Hemisphere. GPS phase scintillation was observed at northern and southern high latitudes by arrays of GPS ionospheric scintillation and TEC monitors (GISTMs) and geodetic-quality GPS receivers sampling at 1 Hz. Mapped as a function of magnetic latitude and magnetic local time (MLT), the scintillation was observed in the ionospheric cusp, the tongue of ionization fragmented into patches, sun-aligned arcs in the polar cap, and nightside auroral oval and subauroral latitudes. Complementing a companion paper (Prikryl et al., 2015a) that focuses on the high-latitude ionospheric response to variable solar wind in the North American sector, interhemispheric comparison reveals commonalities as well as differences and asymmetries between the northern and southern high latitudes, as a consequence of the coupling between the solar wind and magnetosphere. The interhemispheric asymmetries are caused by the dawn–dusk component of the interplanetary magnetic field controlling the MLT of the cusp entry of the storm-enhanced density plasma into the polar cap and the orientation relative to the noon–midnight meridian of the tongue of ionization.

scholarly journals Ionospheric <i>fo</i>F2 anomalies during some intense geomagnetic storms

2005 ◽  
Vol 23 (7) ◽  
pp. 2487-2499 ◽  
Author(s):  
R. P. Kane
Keyword(s):  
Geomagnetic Storms ◽  
Early Morning ◽  
Equatorial Ionosphere ◽  
Storm Event ◽  
Ionospheric Disturbances ◽  
High Latitudes ◽  
Negative Effects ◽  
Local Effects ◽  
Positive Effects ◽  
Low Latitudes

Abstract. The global evolutions of foF2 anomalies were examined for three very intense geomagnetic storms, namely the Halloween events of October-November 2003 (Event X, 29–30 October 2003, Dst –401 nT; Event Y, 20–21 November 2003, Dst –472 nT), and the largest Dst storm (Event Z, 13–14 March 1989, Dst –589 nT). For Event X, troughs (negative storms) were clearly seen for high northern and southern latitudes. For northern midlatitudes as well as for low latitudes, there were very strong positive effects on 29 October 2003, followed by negative effects the next day. For Event Y, there were no troughs in NH high latitudes for morning and evening hours but there were troughs for night. For midlatitudes and low latitudes, some longitudes showed strong negative effects in the early morning as expected, but some longitudes showed strong positive effects at noon and in the evening hours. Thus, there were many deviations from the model patterns. The deviations were erratic, indicating considerable local effects superposed on general patterns. A disconcerting feature was the presence of strong positive effects during the 24 h before the storm commencement. Such a feature appears only in the 24 h before the geomagnetic storm commencement but not earlier. If genuine, these could imply a prediction potential with a 24-h antecedence. For Event Z (13–14 March 1989, equinox), all stations (all latitudes and longitudes) showed a very strong "negative storm" in the main phase, and no positive storms anywhere. Keywords. Ionosphere (Equatorial ionosphere – Ionospheric disturbances – Mid-latitude Ionosphere – Polar ionosphere)

Motions of neutral hydrogen at high latitudes

1967 ◽  
Vol 31 ◽  
pp. 265-278 ◽  
Author(s):  
A. Blaauw ◽  
I. Fejes ◽  
C. R. Tolbert ◽  
A. N. M. Hulsbosch ◽  
E. Raimond
Keyword(s):  
Surface Density ◽  
Velocity Dispersion ◽  
Neutral Hydrogen ◽  
Hydrogen Gas ◽  
High Latitudes ◽  
Low Velocity

Earlier investigations have shown that there is a preponderance of negative velocities in the hydrogen gas at high latitudes, and that in certain areas very little low-velocity gas occurs. In the region 100° &lt;l&lt; 250°, + 40° &lt;b&lt; + 85°, there appears to be a disturbance, with velocities between - 30 and - 80 km/sec. This ‘streaming’ involves about 3000 (r/100)2solar masses (rin pc). In the same region there is a low surface density at low velocities (|V| &lt; 30 km/sec). About 40% of the gas in the disturbance is in the form of separate concentrations superimposed on a relatively smooth background. The number of these concentrations as a function of velocity remains constant from - 30 to - 60 km/sec but drops rapidly at higher negative velocities. The velocity dispersion in the concentrations varies little about 6·2 km/sec. Concentrations at positive velocities are much less abundant.

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