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The interaction of solar wind with earth's magnetic field leads to a number of modifications of the F region global structure. Furthermore, the absorption of solar wind energy has the same phase all over the globe throughout the year. All these imply that there could be simultaneity in UT in global response of some F2 parameters to geomagnetic storms. Presently, F2 region global structure response to geomagnetic storm was studied using foF2 data obtained during the very intense geomagnetic storm (Ap?196) of 13-15 March 1989 from a global network of stations. The ionosonde stations located are at Ouagadougou (12.4), Manila (14.7ºN), Chung-Li (25.0ºN), Kokubunji (35.7ºN), Akita (39.7ºN), Boulder (40.0ºN), Rome (41.8ºN), Ottawa (45.4ºN), Wakkanai (45.4ºN), and Slough (54.5ºN) and Churchill (58.8ºN). The present result obtained using derived ratios R(foF2) show that all the stations showed some high degree of simultaneity in the depletion of foF2 between 0000 and 1200 UT on 14 March.

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The effects of three geomagnetic storms on the ionospheric F region and the influence of the G condition on TEC estimates have been analysed by using ionospheric data from INTA El Arenosillo Atmospheric Sounding Station (37.1N, 353.3E) and GPS TEC measurements obtained at the IGS station of San Fernando (36.5N, 353.8E). The results stress the importance of these perturbations and the need of using edited ionograms.

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The behavior of the horizontal component of the magnetic field obtained by ground magnetometers for three intense magnetic storms that happened during the occurrence of continual auroral activity (HILDCAAs) was studied through a UT-LT analysis. The considered storm periods were August 26–28, 1998, October 21–23, 1999 and April 6–8, 2000. Five minute resolution data were taken from six magnetic observatories, with approximately uniform longitudinal distribution. The results were compared with some interplanetary parameters such as velocity of solar wind, south component of interplanetary magnetic field.

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Exceptional geomagnetic storms were observed in late August and early September 1859. Auroras were observed around the world, and telegraph wires were damaged. Until now, there has been no evidence published of auroral observations in Spain during this famous space weather event. This paper presents Spanish observations that show the aspect of this great aurora from Spain, and the concurrent effects on European telegraph wires. We also computed the variation of the geomagnetic declination in Spain during recent centuries to put these records into context.

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Intense magnetic storms are dominantly caused by the interplanetary manifestations of fast coronal mass ejections (CMEs); and are in two forms: the sheath region and the CME ejecta itself; both involving an intense and long duration southward interplanetary magnetic field component B z . A study of the storm events which were divided into two parts of ‘intense’ −250 nT ≤ peak D st < −100 nT) and ‘very intense’ (peak D st < −250 nT) magnetic activities, each having four storm days spanning between 1976 and 2002 shows that an appreciable southward turning of B z for a value >10 nT and long duration (>3 hour) would always cause a depression in the D st magnitude, signifying an intense storm. The study reveals that ‘very intense’ storms are more likely to experience shock in the interplanetary magnetic field region faster than ‘intense’ storms with a plasma flow speed >400 km/s. This is because D st plots shows that activity of storm sudden commencement (SSC) is not noticeable until about 7 hours to storm day under ‘intense’ storms, whereas, it is as much as 12 hours to storm day for ‘very intense’ activities.The B z plots also shows that B z southward orientation magnitude on the average for ‘very intense’ storms is not beyond −10 nT before the beginning of geomagnetic activity; with a northward orientation occurring less often with a magnitude less than 10 nT. However, a northward directed B z appears more often before storm event in the case of ‘very intense’ storms with a magnitude that could be as high as 15 nT on the average and a southward orientation value not exceeding −10 nT. It was further observed from the D st plot that ‘intense’ storms recover faster than the ‘very intense’ ones.

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Earlier investigations of the inuence of geomagnetic activity on radio wave absorption were based on storm selection criterion: SKp ³ 30. This criterion lumped together weak, moderate, and strong storms, and favouring weak and moderate storms made it impossible for the investigations to detect any change in equatorial radio wave absorption following geomagnetic storms. Presently, the effect of geomagnetic storms on equatorial radio wave absorption has been investigated using severe storms (Ap ? 54) and HF absorption data obtained at 4.87 MHz at 1000 hours LT at Lagos (3. 40oE, 6. 55oN). The absorption data were measured using radio waves reected from the F region, and the transmitter (Radio Cotonou) is located at Cotonou (2.43oE, 6.35oN). The present results obtained using the superposed epoch method show that HF absorption in the equatorial ionosphere increases after severe geomagnetic activity.

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HF absorption enhancements following major geomagnetic storms are analysed, using the superposed epoch method, to examine the geomagnetic latitude limit of the after-effect phenomenon. The absorption data were obtained from one double hop and two single hop A3 transmission paths with ionospheric points at Fgeomag = 3:54oN and ~6. 40oN (15. 40 MHz), Fgeomag ~ 9N (4. 87 MHz), and Fgeomag ~ 11oN (6. 09 MHz) respectively. Presently, the results have shown that enhancement in absorption following major storms could be traced to the low latitude of 3. 54oN.

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This research uses Principal Component Analysis (PCA) to investigate global ionospheric integrated electron content map (GIM) anomalies corresponding to Japan’s Iwate-Miyagi Nairiku earthquake on 13 June 2008 (UT) (M j = 7.2, JMA scale). The PCA transform is applied to GIMs for 20:00 to 22:00 on June 08, 11 and 12, 2008 (UT). To perform the transform, image processing is used to subdivide the GIMs into 100 (36° long. and 18° lat.) smaller maps to form transform matrices of dimensions 2 × 1. The transform allows for principal eigenvalues to be assigned to ionospheric integrated electron content anomalies. Anomalies are represented by large principal eigenvalues (i.e., >0.5 in a normalized set). The possibility of geomagnetic storms and solar flare activity affecting the results is done through examining the D st index for corresponding days. The study shows that for the Iwate-Miyagi Nairiku earthquake, PCA possibly determined earthquake related ionospheric disturbances for the whole region, including the epicenter.

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Nap, Hold, csillagok. A holdciklusok, napkitörések és mágneses viharok hatása az öngyilkosságokra

The impact of moon phases, sun eruptions and geomagnetic storms to suicide

Mentálhigiéné és Pszichoszomatika
Authors:
Zoltán Kmetty
,
Károly Bozsonyi
, and
Álmos Tomasovszky

Elméleti háttér

Az öngyilkosság-kutatások nagyon széles bázison vizsgálják a lehetséges rizikófaktorokat. Már az 1960-as években megjelentek olyan kutatások, amelyek a holdciklus öngyilkosságra gyakorolt lehetséges hatását próbálták meg feltárni. Az ezzel foglalkozó eddigi munkák felemás eredményt hoztak, de inkább arra mutattak, hogy a vizsgálatok középpontjába állított teliholdnak nincsen összefüggése a vizsgált kérdéssel. A különböző naptevékenységek (napkitörés) és ezek földi hatása (mágneses vihar) már kevésbé kutatott téma az öngyilkosság szempontjából. Az eddig eredmények viszont arra mutattak, hogy lehet összefüggés a jelenségek között, bár a csatolási mechanizmust már nem érintették ezek a munkák.

Cél

A tanulmány célja megvizsgálni a holdciklus a napkitörések és a mágneses viharok együtt járását az öngyilkossági gyakoriságokkal. A tanulmányunkban felhasznált több mint 30 évnyi napi magyar öngyilkossági idősor lehetőséget teremt számunkra, hogy más munkákhoz képest sokkal részletesebben tudjuk körbejárni a kérdéskört.

Módszer

Tanulmányunkban az 1976 és 2010 közötti magyarországi öngyilkosságok számának napi normált számát (12784 nap) vizsgáljuk meg a holdciklusok, a napkitörések és a mágneses viharok aspektusából. Az öngyilkossági idősor esetében az évi lakosságszámra normált számok mellett a szezonálisan dekomponált idősorokat is vizsgáljuk (amelyekből a trend- és szezonhatásokat már eltávolítottuk). A holdciklus esetében elsősorban a teliholdra koncentrálunk, a napkitörés esetében külön vizsgáljuk az összes mérhető napkitörést és az erősebb (M/X) napkitöréseket, míg a mágneses viharok esetében a közepes (Ap > 39) és erős (Ap > 100) mágneses viharokat különítjük el. Az egyes jelenségek által érintett és nem érintett napok átlagainak különbségét, Student-féle t-próbával, Welch-féle d-próbával, és ezek rang változataival vizsgáljuk.

Eredmények

A telihold esetében az eredményeink arra mutatnak, hogy a jelenség nem függ össze az öngyilkossággal (csak a nők esetében mutatkozik egy gyenge kapcsolat, és az is csak a normált modellekben). A napkitörések és mágneses viharok vizsgálata már több szignifikáns ösz- szefüggést mutatott, mind a teljes, mind a női és férfi idősorban. Ezt azonban okozhatta a szezon komponens együttmozgása is, mivel a detrendelt és deszezonalizált öngyilkossági idősor esetében ezek az összefüggések már nem voltak azonosíthatók.

Következtetés

A napkitörések és mágneses viharok esetében érdemes tovább folytatni a vizsgálatokat komplexebb statisztikai modellekkel is.

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The goal of this study is to determine whether principal component analysis (PCA) can be used to process latitude-time ionospheric TEC data on a monthly basis to identify earthquake associated TEC anomalies earlier than 5 days before a large (M ≥ 6) earthquake. PCA is applied to latitude-time (mean-of-a-month) ionospheric total electron content (TEC) records collected from the Japan GEONET system to detect TEC anomalies associated with 26 earthquakes in Japan (M ≥ 6.0) from 2004 to 2005. According to the results, PCA was able to discriminate clear TEC anomalies in the months when all 26 earthquakes occurred. After reviewing months when no M ≥ 6.0 earthquakes occurred but geomagnetic storm activity was present, it is possible that the maximal principal eigenvalues PCA returned for these 26 earthquakes indicate earthquake associated TEC anomalies. Previously, PCA has been used to discriminate earthquake-associated TEC anomalies recognized by other researchers who found that statistical association between large earthquakes and TEC anomalies could be established in the 5 days before earthquake nucleation; however, since PCA uses the characteristics of principal eigenvalues to determine earthquake related TEC anomalies, it is possible to show that such anomalies existed earlier than this 5-day statistical window. In this paper, this is shown through the application of PCA to one-dimensional TEC data relating to the Kyushu earthquake of 20 March 2005 (M = 6.6). The analysis is applied to daily TEC and reveals a large principal eigenvalue (representative of an earthquake associated anomaly) for March 9, 11 days before the March 20 earthquake.

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