scholarly journals Defining scale thresholds for geomagnetic storms through statistics

2017 ◽  
Author(s):  
Judith Palacios ◽  
Antonio Guerrero ◽  
Consuelo Cid ◽  
Elena Saiz ◽  
Yolanda Cerrato
Keyword(s):  
Geomagnetic Storms ◽  
Cumulative Distribution ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Disturbances ◽  
Distribution Fitting ◽  
Negative Part ◽  
Absolute Value ◽  
The Absolute ◽  
Best Fit ◽  
High Cadence

Abstract. Geomagnetic storms, as part of the Sun-Earth relations, are continuously monitored with different indices and scales. These indices have some scale thresholds to quantify the severity or risk of geomagnetic disturbances. However, the most usual scale thresholds are arbitrarily chosen. In this work we aim to quantify the range of the thresholds through a new method. These new thresholds are based on statistical distribution fitting. The data used are from a regional real-time high-cadence geomagnetic index, named LDiñ, and its derivative, LCiñ. We considered the negative part of LDiñ, as significant for geomagnetic disturbances; and the absolute value of LCiñ, significant for geomagnetically induced currents. Then we look for the best fit for different statistical continuous distributions applied to these indices. The method yields that the beta prime is the most suitable functions for negative values of LDiñ, whereas power-law and Johnson-SU are the best fits for LCiñ and the whole distribution, respectively. We define new thresholds for intense, very intense and extreme geomagnetic disturbances as the intersects between these best fit distributions and the index complementary cumulative distribution function. Then, thresholds for the negative part of LDiñ, are −100 nT, −205 and −475 nT. The thresholds for the absolute value of LCiñ, are 6, 18 and 32 nT min−1. The thresholds defined here provide criteria to assess the vulnerability to geomagnetic activity on design or mitigation purposes. These threshold definitions will be applied for different products in the Spanish Space Weather Service (SeNMEs) website http://www.senmes.es/index-en.php.

scholarly journals Defining scale thresholds for geomagnetic storms through statistics

2018 ◽  
Author(s):  
Judith Palacios ◽  
Antonio Guerrero ◽  
Consuelo Cid ◽  
Elena Saiz ◽  
Yolanda Cerrato
Keyword(s):  
Geomagnetic Storms ◽  
Distribution Functions ◽  
Quiet Time ◽  
Geomagnetic Disturbances ◽  
Distribution Fitting ◽  
F Distribution ◽  
Student’S T ◽  
Best Fit ◽  
Usual Scale

Abstract. Geomagnetic storms, as part of the Sun-Earth relations, are continuously monitored with different indices and scales. These indices usually have some associated scale thresholds to quantify the severity or risk of geomagnetic disturbances. However, the most usual scale thresholds are arbitrarily chosen. In this work we aim to quantify the range of the thresholds through a new method. These new thresholds are based on statistical distribution fitting. We used different geomagnetic indices, as Dst, SYM-H, and Kp, since they are relevant for space weather purposes. The first two indices have been discriminated between their negative values and the whole dataset. We considered two periods: a short-term one, comprising data from 1997 to 2012; and long-term ones, which are from 1957–2012 for Dst and 1932–2012 for Kp. We look for the best fit for different statistical continuous distributions applied to these indices. The best fits and the data distribution functions yield to intersects that can be used to define thresholds. The best fit distribution functions are more coincidental between them when considering determined similar datasets, as non-central f-distribution for negative values, meaningful for geomagnetic disturbances; or non-central Student's-t, when the whole dataset is taken. The method yields different values for thresholds depending on the index. Thresholds for geomagnetic storms can be chosen by common values of SYM-H and Dst, as −75 nT for moderate storms; −150 nT for intense storms, and −330 nT for extreme storms. For the case of Kp, the value equal to 5 may mark the departure from quiet time to stormy time. The obtained values are close to those usually considered as thresholds for, typically, Dst and Kp; therefore the thresholds defined here may provide criteria to assess the vulnerability to geomagnetic activity on design or mitigation purposes.

The quantification and possible sources of spatially structured and large amplitude geomagnetic depressions during strong geomagnetic storms measured by IMAGE

2021 ◽  
Author(s):  
Andrew Dimmock ◽  
Lisa Rosenqvist ◽  
Ari Viljanen ◽  
Colin Forsyth ◽  
Mervyn Freeman ◽  
...  
Keyword(s):  
Space Weather ◽  
Geomagnetic Storms ◽  
Dynamical Behaviour ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Disturbances ◽  
Modeling Framework ◽  
Coupling Dynamics ◽  
Weather Modeling ◽  
Induced Currents ◽  
Coupling Processes

<p>Geomagnetically Induced Currents (GICs) are a space weather hazard that can negatively impact large ground-based infrastructures such as power lines, pipelines, and railways. They are driven by the dynamic spatiotemporal behaviour of currents flowing in geospace, which drive rapid geomagnetic disturbances on the ground. In some cases, geomagnetic disturbances are highly localised and spatially structured due to the dynamical behaviour of geospace currents and magnetosphere-ionosphere (M-I) coupling dynamics, which are complex and often unclear.</p><p>In this work, we investigate and quantify the spatial structure of large geomagnetic depressions exceeding several hundred nT according to the 10 strongest events measured over Fennoscandia by IMAGE. Using ground magnetometer measurements we connect these spatially structured geomagnetic disturbances to possible M-I coupling processes and identify their likely magnetospheric origin. In addition, the ability for these disturbances to drive large GICs is assessed by calculating their respective geoelectric fields in Sweden using the SMAP ground conductivity model. To compliment the observations, we also utilise high resolution runs (>7 million cells) of the Space Weather Modeling Framework (SWMF) to determine to what extent global MHD models can capture this behaviour.</p>

scholarly journals Incentive Function of Audit Opinion for the Increase of Regional Operational Expenditure and Own-Source Revenues Through Sensitivity Analysis in Indonesia

2020 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Muhammad Ikbal Abdullah ◽  
Andi Chairil Furqan ◽  
Nina Yusnita Yamin ◽  
Fahri Eka Oktora
Keyword(s):  
Sensitivity Analysis ◽  
Significant Influence ◽  
Provincial Government ◽  
Sensitivity Testing ◽  
Audit Opinion ◽  
Absolute Value ◽  
Operating Expenditure ◽  
The Absolute ◽  
Operational Expenditure

This study aims to analyze the sensitivity testing using measurements of realization of regional own-source revenues and operating expenditure and to analyze the extent of the effect of sample differences between Java and non-Java provinces by using samples outside of Java. By using sensitivity analysis, the results found the influence of audit opinion on the performance of the provincial government mediated by the realization of regional operating expenditure. More specifically, when using the measurement of the absolute value of the realization of regional operating expenditure it was found that there was a direct positive and significant influence of audit opinion on the performance of the Provincial Government. However, no significant effect of audit opinion was found on the realization value of regional operating expenditure and the effect of the realization value of regional operating expenditure on the performance of the Provincial Government. This result implies that an increase in audit opinion will be more likely to be used as an incentive for the Provincial Government to increase the realization of regional operating expenditure.

Die Bedeutung der Homogenisationsart und -intensität für die Größe und Konstanz der Sauerstoffaufnahme von Meerschweinchen-Leberhomogenat / The Influence of Mode and Intensity of Homogenization on the Absolute Value and Stability of Oxygen Consumption of Guinea Pig Liver Homogenates

1977 ◽  
Vol 32 (11-12) ◽  
pp. 908-912 ◽  
Author(s):  
H. J. Schmidt ◽  
U. Schaum ◽  
J. P. Pichotka
Keyword(s):  
Oxygen Uptake ◽  
Guinea Pig ◽  
Measuring Time ◽  
Pig Liver ◽  
Absolute Value ◽  
Modified Method ◽  
Simultaneous Measurements ◽  
Liver Homogenates ◽  
The Absolute ◽  
Guinea Pig Liver

Abstract The influence of five different methods of homogenisation (1. The method according to Potter and Elvehjem, 2. A modification of this method called Potter S, 3. The method of Dounce, 4. Homogenisation by hypersonic waves and 5. Coarce-grained homogenisation with the “Mikro-fleischwolf”) on the absolute value and stability of oxygen uptake of guinea pig liver homogenates has been investigated in simultaneous measurements. All homogenates showed a characteristic fall of oxygen uptake during measuring time (3 hours). The modified method according to Potter and Elvehjem called Potter S showed reproducible results without any influence by homogenisation intensity.

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.

Thue equations that simultaneously fail the Hasse principle

2021 ◽  
pp. 1-10
Author(s):  
PALOMA BENGOECHEA
Keyword(s):  
Positive Integer ◽  
Hasse Principle ◽  
Fixed Degree ◽  
Binary Forms ◽  
Absolute Value ◽  
Positive Proportion ◽  
The Absolute

Abstract We refine a previous construction by Akhtari and Bhargava so that, for every positive integer m, we obtain a positive proportion of Thue equations F(x, y) = h that fail the integral Hasse principle simultaneously for every positive integer h less than m. The binary forms F have fixed degree ≥ 3 and are ordered by the absolute value of the maximum of the coefficients.

Comparison of the acceleration due to gravity at the National Physical Laboratory, Teddington, the Bureau International des Poids et Mesures, Sèvres, the Physikalisch-Technische Bundesanstalt, Brunswick, and the Geodetic Institute, Potsdam

1952 ◽  
Vol 213 (1114) ◽  
pp. 408-424 ◽  
Keyword(s):  
National Physical Laboratory ◽  
Absolute Value ◽  
Geodetic Institute ◽  
Physical Laboratory ◽  
The Absolute

The values of gravity at these stations have been compared by means of pendulum observations with Invar invariable pendulums. The observed differences of gravity from the National Physical Laboratory are: B. I. P. M. -256·73 ± 0·49 mgal P. T. B. + 68·68 ± 0·49 mgal Bad Harzburg - 15·68 ± 0·49 mgal The accuracy of the measurements is not so great as has been achieved once or twice previously with the same apparatus, mainly because the changes in the lengths of the pendulums were greater than usual. These differences have been combined with German pendulum observations and with gravimeter comparisons with the following results: Value of gravity at N. P. L. on the Potsdam system: 981196·29 ± 0·3 mgal. Differences between sites of absolute determinations of gravity: N. P. L. - B. I. P. M. +256·45 ± 0·3 mgal N. P. L. - P. T. B. - 68·98 ± 0·3 mgal P. T. B. - Potsdam - 8·95 ± 0·4 mgal ( g at Potsdam = 981274 mgal.) The effects of these results on gravity surveys based on Cambridge and on the absolute value of gravity are indicated.

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