ANALYSES OF GEOMAGNETIC DATA SETS FROM OBSERVATORIES AND CORRELATION BETWEEN THEM

2020 ◽  
Author(s):  
Laurențiu Asimopolos ◽  
◽  
Natalia-Silvia Asimopoli ◽  
drian-Aristide Asimopolos
Keyword(s):  
Wavelet Analysis ◽  
Geomagnetic Storm ◽  
Geomagnetic Field ◽  
Graphical Representation ◽  
Geomagnetic Storms ◽  
Correlation Coefficients ◽  
Finite Energy ◽  
Solar Cycles ◽  
Time Intervals ◽  
Geomagnetic Data

The purpose of this study was to analyze the associated spectrum of geomagnetic field, frequencies intensity and the time of occurrence. We calculated the variation of the correlation coefficients, with mobile windows of various sizes, for the recorded magnetic components at different latitudes and latitudes. We included in our study the observatories: Surlari (USA), Honolulu (HON), Scott Base (SBA), Kakioka (KAK), Tihany (THY), Uppsala (UPS), Wingst (WNG) and Yellowknife (YKC). We used the data of these observatories from INTERMAGNET for the bigest geomagnetic storm from the last two Solar Cycles. We have used for this purpose a series of filtering algorithms, spectral analysis and wavelet with different mother functions at different levels. In the paper, we show the Fourier and wavelet analysis of geomagnetic data recorded at different observatories regarding geomagnetic storms. Fourier analysis highlight predominant frequencies of magnetic field components. Wavelet analysis provides information about the frequency ranges of magnetic fields, which contain long time intervals for medium frequency information and short time intervals for highlight frequencies, details of the analyzed signals. Also, the wavelet analysis allows us to decompose geomagnetic signals in different waves. The analyzes presented are significant for the studied of the geomagnetic storm. The data for the next days after the storm showed a mitigation of the perturbations and a transition to a quiet day of the geomagnetic field. In both, the Fourier Transformation and the Wavelet Transformation, transformation evaluation involves the calculation of a scalar product between the analyzed signal and a set of signals that form a particular base in the vector space of the finite energy signals. Fourier representation use and orthogonal vectors base, whereas in the case of wavelet there is the possibility to use also bases consisting of independent linear non-orthogonal vectors. Unlike the Fourier transform, which depends only on a single parameter, wavelet transform type depends on two parameters, a and b. As a result, the graphical representation of the spectrum is different, wavelet analysis bringing more information about geomagnetic pattern of each observatory with that own specific conditions

scholarly journals Statistics of the largest geomagnetic storms per solar cycle (1844-1993)

1997 ◽  
Vol 15 (6) ◽  
pp. 719-728 ◽  
Author(s):  
D. M. Willis ◽  
P. R. Stevens ◽  
S. R. Crothers
Keyword(s):  
Statistical Analysis ◽  
Solar Cycle ◽  
Geomagnetic Storm ◽  
Extreme Values ◽  
Geomagnetic Storms ◽  
Extreme Value ◽  
Extreme Value Statistics ◽  
Relative Dispersion ◽  
Solar Cycles ◽  
Aa Index

Abstract. A previous application of extreme-value statistics to the first, second and third largest geomagnetic storms per solar cycle for nine solar cycles is extended to fourteen solar cycles (1844–1993). The intensity of a geomagnetic storm is measured by the magnitude of the daily aa index, rather than the half-daily aa index used previously. Values of the conventional aa index (1868–1993), supplemented by the Helsinki Ak index (1844–1880), provide an almost continuous, and largely homogeneous, daily measure of geomagnetic activity over an interval of 150 years. As in the earlier investigation, analytic expressions giving the probabilities of the three greatest storms (extreme values) per solar cycle, as continuous functions of storm magnitude (aa), are obtained by least-squares fitting of the observations to the appropriate theoretical extreme-value probability functions. These expressions are used to obtain the statistical characteristics of the extreme values; namely, the mode, median, mean, standard deviation and relative dispersion. Since the Ak index may not provide an entirely homogeneous extension of the aa index, the statistical analysis is performed separately for twelve solar cycles (1868–1993), as well as nine solar cycles (1868–1967). The results are utilized to determine the expected ranges of the extreme values as a function of the number of solar cycles. For fourteen solar cycles, the expected ranges of the daily aa index for the first, second and third largest geomagnetic storms per solar cycle decrease monotonically in magnitude, contrary to the situation for the half-daily aa index over nine solar cycles. The observed range of the first extreme daily aa index for fourteen solar cycles is 159–352 nT and for twelve solar cycles is 215–352 nT. In a group of 100 solar cycles the expected ranges are expanded to 137–539 and 177–511 nT, which represent increases of 108% and 144% in the respective ranges. Thus there is at least a 99% probability that the daily aa index will satisfy the condition aa < 550 for the largest geomagnetic storm in the next 100 solar cycles. The statistical analysis is used to infer that remarkable conjugate auroral observations on the night of 16 September 1770, which were recorded during the first voyage of Captain Cook to Australia, occurred during an intense geomagnetic storm.

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 Fractals and magnetic storm

1996 ◽  
Vol 14 (9) ◽  
pp. 888-892 ◽  
Author(s):  
Tan-Wen Wang
Keyword(s):  
Quantitative Analysis ◽  
Magnetic Storm ◽  
Geomagnetic Storm ◽  
Geomagnetic Storms ◽  
Fractal Theory ◽  
Fractal Dimensions ◽  
Time Intervals ◽  
Maximum Value ◽  
Magnetic Index ◽  
Better Than

Abstract. Fractal theory is applied in a quantitative analysis of geomagnetic storms. Fractal dimensions (D) of the attractor for storm data from the Beijing observatory (40.0°N, 116.2°E) using several time intervals are calculated. A maximum value of 1.4 has been obtained for a geomagnetic storm; on quite days the dimension is only slightly larger than 0.5. Data from two storms are analyzed here. Results show that a combination of both D and the magnetic index, k, can perhaps describe the degree of solar disturbance better than the single parameter k.

A prospective randomized study to assess the efficacy of post-operative nasal medication after endonasal surgery

1995 ◽  
Vol 109 (7) ◽  
pp. 618-621 ◽  
Author(s):  
Paul D. R. Spraggs ◽  
Marcelle Macnamara ◽  
Theo Joseph
Keyword(s):  
Randomized Study ◽  
Correlation Coefficients ◽  
Control Group ◽  
Time Intervals ◽  
Treatment Groups ◽  
Ephedrine Hydrochloride ◽  
Patent Airway ◽  
Significant Difference ◽  
Blood Clots ◽  
Betamethasone Sodium Phosphate

AbstractPost-operative nasal medications are commonly used following routine septal or turbinate surgery but their efficacy in removing blood clots, improving the sensation of a patent airway and promoting healing are unknown. This prospective randomized trial of patients undergoing septal and/or turbinate surgery assessed the efficacy of three commonly used nasal medicines, 0.5 per cent ephedrine hydrochloride nasal drops, betamethasone sodium phosphate (Betnosol®) nose drops and alkaline nasal douches, in producing the sensation of a patent airway in the 14 days following surgery. Ninety-seven patients were randomized into the three treatment groups and a control group who received no nasal medication. Patients assessed their nasal patency by means of a visual analogue scale (VAS) and any complications of treatment were recorded. Statistical analysis of the 76 complete sets of results using the Mann-Whitney U-test showed that there was a significant difference in the distribution of all of the treatments for each of the time intervals (p<0.05). Glass rank biserial correlation coefficients were all small (rg<0.085) but the most significant differences were between ephedrine and the control group at two hours, two, seven and 10 days (0.02, 0.054, 0.057, 0.085 respectively), alkaline nasal douches being most significant at four and 14 days (0.06 and 0.0722 respectively).

scholarly journals Development and application of problem-oriented digital twins for magnetic observatories and variation stations

2021 ◽  
pp. 60-71
Author(s):  
Andrei Vorobev ◽  
Vyacheslav Pilipenko ◽  
Gulnara Vorobeva ◽  
Olga Khristodulo
Keyword(s):  
Time Series ◽  
Geomagnetic Field ◽  
Missing Values ◽  
Information Environment ◽  
Small Scale ◽  
Geomagnetic Variation ◽  
Digital Twin ◽  
Digital Twins ◽  
Geomagnetic Data ◽  
Magnetic Station

Introduction: Magnetic stations are one of the main tools for observing the geomagnetic field. However, gaps and anomalies in time series of geomagnetic data, which often exceed 30% of the number of recorded values, negatively affect the effectiveness of the implemented approach and complicate the application of mathematical tools which require that the information signal is continuous. Besides, the missing values ​​add extra uncertainty in computer simulation of dynamic spatial distribution of geomagnetic variations and related parameters. Purpose: To develop a methodology for improving the efficiency of technical means for observing the geomagnetic field. Method: Creation of problem-oriented digital twins of magnetic stations, and their integration into the collection and preprocessing of geomagnetic data, in order to simulate the functioning of their physical prototypes with a certain accuracy. Results: Using Kilpisjärvi magnetic station (Finland) as an example, it is shown that the use of digital twins, whose information environment is made up of geomagnetic data from adjacent stations, can provide the opportunity for reconstruction (retrospective forecast) of geomagnetic variation parameters with a mean square error in the auroral zone of up to 11.5 nT. The integration of problem-oriented digital twins of magnetic stations into the processes of collecting and registering geomagnetic data can provide automatic identification and replacement of missing and abnormal values, increasing, due to the redundancy effect, the fault tolerance of the magnetic station as a data source object. For example, the digital twin of Kilpisjärvi station recovers 99.55% of annual information, and 86.73% of it has an error not exceeding 12 nT. Discussion: Due to the spatial anisotropy of geomagnetic field parameters, the error at the digital twin output will be different in each specific case, depending on the geographic location of the magnetic station, as well as on the number of the surrounding magnetic stations and the distance to them. However, this problem can be minimized by integrating geomagnetic data from satellites into the information environment of the digital twin. Practical relevance: The proposed methodology provides the opportunity for automated diagnostics of time series of geomagnetic data for outliers and anomalies, as well as restoration of missing values and identification of small-scale disturbances.

scholarly journals Evaluation of possible corrosion enhancement due to telluric currents: case study of the Bolivia–Brazil pipeline

2020 ◽  
Vol 38 (4) ◽  
pp. 881-888
Author(s):  
Joyrles Fernandes de Moraes ◽  
Igo Paulino ◽  
Lívia R. Alves ◽  
Clezio Marcos Denardini
Keyword(s):  
Corrosion Rate ◽  
Space Weather ◽  
Geomagnetic Storms ◽  
Corrosion Process ◽  
Fluxgate Magnetometer ◽  
Weather Events ◽  
Source Line ◽  
Geomagnetic Data ◽  
Telluric Currents

Abstract. The electric field induced in the Bolivia–Brazil gas pipeline (GASBOL) was calculated by using the distributed source line transmission (DSLT) theory during several space weather events. We used geomagnetic data collected by a fluxgate magnetometer located at São José dos Campos (23.2∘ S, 45.9∘ W). The total corrosion rate was calculated by using the Gummow (2002) methodology and was based on the assumption of a 1 cm hole in the coating of the pipeline. The calculations were performed at the ends of pipeline where the largest “out-of-phase” pipe-to-soil potential (PSP) variations were obtained. The variations in PSP during the 17 March 2015 geomagnetic storm have led to the greatest corrosion rate of the analyzed events. All the space weather events evaluated with high terminating impedance may have contributed to increases in the corrosion process. The applied technique can be used to evaluate the corrosion rate due to the high telluric activity associated with the geomagnetic storms at specific locations.

scholarly journals From solar eruption to transformer saturation: the space weather chain

2013 ◽  
Vol 8 (S300) ◽  
pp. 500-501
Author(s):  
Larisa Trichtchenko
Keyword(s):  
Space Weather ◽  
Geomagnetic Field ◽  
Geomagnetic Storms ◽  
Interplanetary Medium ◽  
Practical Importance ◽  
Power Grids ◽  
Geomagnetically Induced Currents ◽  
Large Space ◽  
Weather Events ◽  
Induced Currents

AbstractCoronal mass ejections (CME) and associated interplanetary-propagated solar wind disturbances are the established causes of the geomagnetic storms which, in turn, create the most hazardous impacts on power grids. These impacts are due to the large geomagnetically induced currents (GIC) associated with variations of geomagnetic field during storms, which, flowing through the transformer windings, cause extra magnetisation. That can lead to transformer saturation and, in extreme cases, can result in power blackouts. Thus, it is of practical importance to study the solar causes of the large space weather events. This paper presents the example of the space weather chain for the event of 5-6 November 2001 and a table providing complete overview of the largest solar events during solar cycle 23 with their subsequent effects on interplanetary medium and on the ground. This compact overview can be used as guidance for investigations of the solar causes and their predictions, which has a practical importance in everyday life.

Analysis of Secular Variations of Geomagnetic Field in Lithuania Based on the Survey in 2016

2017 ◽  
Author(s):  
Arunas Buga ◽  
Simona Einorytė ◽  
Romuald Obuchovski ◽  
Vytautas Puškorius ◽  
Petras Petroškevicius
Keyword(s):  
Geomagnetic Field ◽  
Field Research ◽  
Field Measurements ◽  
Geomagnetic Observatory ◽  
Research Activities ◽  
Secular Variations ◽  
Geomagnetic Data ◽  
The Mean ◽  
Using Data ◽  
Magnetic Field Variations

Lithuania is successfully integrated in the European geomagnetic field research activities. Six secular variation research stations were established in 1999 and precise geomagnetic field measurements were performed there in 1999, 2001, 2004, 2007 and 2016. Obtained diurnal magnetic field variations at measuring station and neighbouring observatories were analysed. All measurements are reduced to the mean of the year using data from geomagnetic observatory of Belsk. Based on the measured data the analysis of geomagnetic field parameter secular changes was performed. Results of the presented research are useful for updating the old geomagnetic data as well as for estimation of accuracy of declination model.

scholarly journals On the radiation belt location during the 23rd and 24th solar cycles

2019 ◽  
Vol 37 (4) ◽  
pp. 719-732
Author(s):  
Alexei V. Dmitriev
Keyword(s):  
North American ◽  
Geomagnetic Field ◽  
Radiation Belt ◽  
Occurrence Rate ◽  
Solar Cycles ◽  
Geomagnetic Jerk ◽  
Outer Radiation Belt ◽  
Energetic Electrons ◽  
Eastern Hemisphere

Abstract. Within the last two solar cycles (from 2001 to 2018), the location of the outer radiation belt (ORB) was determined using NOAA/Polar-orbiting Operational Environmental Satellite (POES) observations of energetic electrons with energies above 30 keV. It was found that the ORB was shifted a little (∼1∘) in the European and North American sectors, while in the Siberian sector the ORB was displaced equatorward by more than 3∘. The displacements corresponded qualitatively to the change in the geomagnetic field predicted by the IGRF-12 model. However, in the Siberian sector, the model has a tendency to underestimate the equatorward shift of the ORB. The shift became prominent after 2012, which might have been related to a geomagnetic “jerk” that occurred in 2012–2013. The displacement of the ORB to lower latitudes in the Siberian sector can contribute to an increase in the occurrence rate of midlatitude auroras observed in the Eastern Hemisphere.

Sign in / Sign up

Export Citation Format

Share Document