Regional-scale high-latitude extreme geoelectric fields pertaining to geomagnetically induced currents

Pulkkinen, A.; Bernabeu, E.; Eichner, Jan F.; Viljanen, A.; Ngwira, Chigomezyo M.

doi:10.1186/s40623-015-0255-6

Cited by 72 publications

(91 citation statements)

References 21 publications

(19 reference statements)

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“…In Figure 4 with the full conductivity model, the high-resistive area in the north (block 24) leads to an enhanced electric field there. Pulkkinen et al (2015) present sample plots of the modelled electric field close to and within the same region, demonstrating notable spatial variations when a single conductivity model was assumed (different from the one applied here).…”

Section: Resultsmentioning

confidence: 99%

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Influence of spatial variations of the geoelectric field on geomagnetically induced currents

Viljanen

Pirjola

2017

J. Space Weather Space Clim.

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-The geoelectric field driving geomagnetically induced currents (GIC) has complex spatial variations. It follows that different patterns of the field vectors in a given area having the same regional mean can produce very different GIC. In this study, we consider a few power grid models and calculate GIC due to a modelled geoelectric field with a regional mean magnitude of 1 V/km. Altogether 8035 snapshots of the electric field are included. We also assume two different ground conductivity models, of which the simpler one consists of two layers across the whole region, and another model has four different two-layer blocks. As a measure of GIC, we use the sum of currents at all substations of the power grid. We also consider the distribution of GIC at a single site. For a given grid, differences between the two ground conductivity models are small. When comparing different power grid models, the sum of GIC varies relatively more for a grid with a small number of substations and transmission lines. When the area and the number of substations increase, the relative difference between the smallest and largest GIC sum decreases. In all cases, assuming a spatially uniform electric field leads to a reasonable estimation of the GIC magnitudes, but it does not produce the largest GIC sum. For a single substation, there is a large variety of GIC values due to different electric field configurations.

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Section: Resultsmentioning

confidence: 99%

“…This is obviously due to a pronounced local enhancement of the electric field, and this underlines the need to understand localised features in addition to regional scales (cf. Ngwira et al, 2015;Pulkkinen et al, 2015).…”

Section: Block 24mentioning

confidence: 99%

Influence of spatial variations of the geoelectric field on geomagnetically induced currents

Viljanen

Pirjola

2017

J. Space Weather Space Clim.

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“…The relevance of E or dB/dt to GIC has led to several studies related to their extreme behaviour (Wik et al, 2009;Myllys et al, 2014;Pulkkinen et al, 2015). In Thomson et al (2011) extreme event analysis (EVA) was performed on dB/dt from stations covering similar latitudes as in this study, and 100-and 200-year return levels were estimated.…”

Section: P Wintoft Et Al: Extreme Value Analysis Of Magnetic and Elmentioning

confidence: 99%

Extreme value analysis of the time derivative of the horizontal magnetic field and computed electric field

Wintoft¹,

Viljanen²,

Wik³

2016

Ann. Geophys.

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Abstract. High-frequency ( ≈ minutes) variability of ground magnetic fields is caused by ionospheric and magnetospheric processes driven by the changing solar wind. The varying magnetic fields induce electrical fields that cause currents to flow in man-made conductors like power grids and pipelines. Under extreme conditions the geomagnetically induced currents (GIC) may be harmful to the power grids. Increasing our understanding of the extreme events is thus important for solar-terrestrial science and space weather. In this work 1-min resolution of the time derivative of measured local magnetic fields (|dB h /dt|) and computed electrical fields (E h ), for locations in Europe, have been analysed with extreme value analysis (EVA). The EVA results in an estimate of the generalized extreme value probability distribution that is described by three parameters: location, width, and shape. The shape parameter controls the extreme behaviour. The stations cover geomagnetic latitudes from 40 to 70 • N. All stations included in the study have contiguous coverage of 18 years or more with 1-min resolution data. As expected, the EVA shows that the higher latitude stations have higher probability of large |dB h /dt| and |E h | compared to stations further south. However, the EVA also shows that the shape of the distribution changes with magnetic latitude. The high latitudes have distributions that fall off faster to zero than the low latitudes, and upward bounded distributions can not be ruled out. The transition occurs around 59-61 • N magnetic latitudes. Thus, the EVA shows that the observed series north of ≈ 60 • N have already measured values that are close to the expected maxima values, while stations south of ≈ • N will measure larger values in the future.

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“…Alekseev et al (2015) construct the heterogeneous resistivity structure in the Earth, which is important for the evaluation of the GIEs. Pulkkinen et al (2015b) demonstrate that the GIEs also can be locally enhanced when the source structure is highly heterogeneous. Next, realistic reproduction of GIEs and Open Access *Correspondence: sfujita@mc-jma.go.jp 1 Meteorological College, Kashiwa, Japan Full list of author information is available at the end of the article GICs from the magnetic storm data is reported by several papers.…”

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confidence: 84%

Extremely severe space weather and geomagnetically induced currents in regions with locally heterogeneous ground resistivity

Fujita¹,

Kataoka

Fujii³

et al. 2016

Earth Planet Sp

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Regional-scale high-latitude extreme geoelectric fields pertaining to geomagnetically induced currents

Cited by 72 publications

References 21 publications

Influence of spatial variations of the geoelectric field on geomagnetically induced currents

Influence of spatial variations of the geoelectric field on geomagnetically induced currents

Extreme value analysis of the time derivative of the horizontal magnetic field and computed electric field

Extremely severe space weather and geomagnetically induced currents in regions with locally heterogeneous ground resistivity

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