Studies on sudden commencements of geomagnetic storms using IGY data from United States stations

Solar Energy ◽  
1960 ◽  
Vol 4 (4) ◽  
pp. 42
Keyword(s):  
United States ◽  
Geomagnetic Storms ◽  
Sudden Commencements

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 Sporadic aurorae observed in East Asia

2007 ◽  
Vol 25 (2) ◽  
pp. 417-436 ◽  
Author(s):  
D. M. Willis ◽  
F. R. Stephenson ◽  
Keyword(s):  
United States ◽  
East Asia ◽  
Geomagnetic Storms ◽  
East Asian ◽  
Scientific Information ◽  
The United States ◽  
Royal Greenwich Observatory ◽  
Historical Sources ◽  
Approximate Location ◽  
Auroral Luminosity

Abstract. All the accessible auroral observations recorded in Chinese and Japanese histories during the interval AD 1840–1911 are investigated in detail. Most of these auroral records have never been translated into a Western language before. The East Asian auroral reports provide information on the date and approximate location of each auroral observation, together with limited scientific information on the characteristics of the auroral luminosity such as colour, duration, extent, position in the sky and approximate time of occurrence. The full translations of the original Chinese and Japanese auroral records are presented in an appendix, which contains bibliographic details of the various historical sources. (There are no known reliable Korean observations during this interval.) A second appendix discusses a few implausible "auroral" records, which have been rejected. The salient scientific properties of all exactly dated and reliable East Asian auroral observations in the interval AD 1840–1911 are summarised succinctly. By comparing the relevant scientific information on exactly dated auroral observations with the lists of great geomagnetic storms compiled by the Royal Greenwich Observatory, and also the tabulated values of the Ak (Helsinki) and aa (Greenwich and Melbourne) magnetic indices, it is found that 5 of the great geomagnetic storms (aa>150 or Ak>50) during either the second half of the nineteenth century or the first decade of the twentieth century are clearly identified by extensive auroral displays observed in China or Japan. Indeed, two of these great storms produced auroral displays observed in both countries on the same night. Conversely, at least 29 (69%) of the 42 Chinese and Japanese auroral observations occurred at times of weak-to-moderate geomagnetic activity (aa or Ak≤50). It is shown that these latter auroral displays are very similar to the more numerous (about 50) examples of sporadic aurorae observed in the United States during the interval AD 1880–1940. The localised nature and spatial structure of some sporadic aurorae observed in East Asia is indicated by the use of descriptive terms such as "lightning", "rainbow", "streak" and "grid".

scholarly journals A Method for Recognition of Sudden Commencements of Geomagnetic Storms Using Digital Differentiating Filters

2022 ◽  
Vol 12 (1) ◽  
pp. 413
Author(s):  
Victor Getmanov ◽  
Roman Sidorov ◽  
Alexei Gvishiani
Keyword(s):  
Decision Making ◽  
False Recognition ◽  
Geomagnetic Field ◽  
Geomagnetic Storms ◽  
Maximum Amplitude ◽  
Sudden Commencement ◽  
Magnetic Components ◽  
Observatory Data ◽  
Sudden Commencements ◽  
Decision Making Rule

This article describes a method for recognizing sudden commencement events using digital differentiating filters. This method is applied to INTERMAGNET observatory data. Maximum amplitude derivatives for the magnetic components (X, Y, Z) and the total intensity (F) of the geomagnetic field are introduced, and the decision-making rule is formulated. The authors developed a procedure for selecting optimal digital differentiating filters. Estimates of probabilities of correct and false recognition of sudden commencements were obtained. The calculations of the probabilistic characteristics have confirmed the effectiveness of the method.

scholarly journals Seasonal variations in the occurrence of geomagnetic storms

1996 ◽  
Vol 14 (3) ◽  
pp. 286-289 ◽  
Author(s):  
John R. Taylor ◽  
Mark Lester ◽  
Timothy K. Yeoman
Keyword(s):  
Solar Wind ◽  
Seasonal Variations ◽  
Annual Variation ◽  
Geomagnetic Storms ◽  
Magnetic Activity ◽  
Magnetic Storms ◽  
Sudden Commencement ◽  
Sudden Commencements ◽  
Solar Wind Origin

Abstract. Seasonal variations in the onset of magnetic storms are investigated. For the purposes of this study storms have been defined as events in which Dst falls below –50 nT for at least four consecutive hours. The storms have been classified as either storm sudden commencements (SSCs; storms initiated by a sudden commencement) or as storm gradual commencements (SGCs; all other storms). It is found that the semi-annual variation of magnetic activity is reflected in the occurrence statistics of SGC events only, indicative that the solar wind origin is different for SSCs and SGCs. It is suggested that the heliospheric latitude model of seasonal magnetic activity is relatively ineffective in modulating the previously observed seasonal variations in the occurrence of magnetic storms.

scholarly journals Sudden Commencements of Geomagnetic Storms and Their Local Irregularities

1965 ◽  
Vol 17 (1) ◽  
pp. 69-93 ◽  
Author(s):  
Rikio MAEDA ◽  
Tsuneji RIKITAKE ◽  
Takesi NAGATA
Keyword(s):  
Geomagnetic Storms ◽  
Sudden Commencements
Sign in / Sign up

Export Citation Format

Share Document