High‐latitude ionospheric equivalent currents during strong space storms: Regional perspective

Juusola, Liisa; Viljanen, A.; Kamp, Max van de; Tanskanen, Eija; Vanhamäki, Heikki; Partamies, Noora; Kauristie, Kirsti

doi:10.1002/2014sw001139

Cited by 36 publications

(64 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The statistical maps were constructed from the 10 s maps. Only grid points of the 10 s maps within 200 km horizontal distance [ Juusola et al , ] from the closest operational magnetometer were included when calculating the statistical maps. The temporal mean (denoted by “<>”) was calculated from the x and y components of the equivalent current density and its time derivative for each grid cell separately as

< normald {boldJ}_{eq} / normald t > = < normald J_{eq, x} / normald t > boldx + < normald J_{eq, y} / normald t > boldy

< | d {boldJ}_{eq} / normald t | > = < \sqrt{{(normald J_{eq, x} / normald t)}^{2} + {(normald J_{eq, y} / normald t)}^{2}} >

< normald | {boldJ}_{eq} | / normald t > = < normald \sqrt{J_{eq, x}^{2} + J_{eq, y}^{2}} / normald t >

< {boldJ}_{eq} > = < J_{eq, x} > boldx + < J_{eq, y} > boldy

< | {boldJ}_{eq} | > = < \sqrt{J_{eq, x}^{2} + J_{eq, y}^{2}} >

…”

Section: Methodsmentioning

confidence: 99%

Solar wind control of ionospheric equivalent currents and their time derivatives

et al. 2015

Self Cite

View full text Add to dashboard Cite

A solid understanding of the solar wind control of ground magnetic field disturbances is essential for utilizing the existing long time series of ground data to obtain information on solar wind‐magnetosphere‐ionosphere coupling. We have used 20 years of International Monitor for Auroral Geomagnetic Effects magnetometer data (54°–76° magnetic latitude) to study the solar wind control of the ionospheric equivalent current density and its time derivative (<|dJeq/dt|>). We found that <|dJeq/dt|> peaks at the premidnight and prenoon ends of the westward electrojet. The prenoon <|dJeq/dt|> peak was most intense during fast solar wind and radial interplanetary magnetic field (IMF). The location of the peak was not affected by the IMF orientation but persisted at 8–10 magnetic local time and 70°–75° latitude, near the boundary between the westward and eastward electrojets. Sensitivity of this boundary to disturbances was suggested as a possible explanation for the persistent prenoon location of the peak. The premidnight peak was most intense during southward IMF orientation. While faster solar wind mainly resulted in more intense <|dJeq/dt|> in the premidnight sector, stronger IMF caused the region of intense <|dJeq/dt|> to spread to the postmidnight, dawn, and dusk sectors. A good correspondence was found between development of the nightside <|dJeq/dt|> intensification and average substorm bulge and oval aurora as determined by Gjerloev et al. (2007). The bulge aurora covered the western end of the westward electrojet where the equivalent current also had a significant poleward component. The substorm oval aurora, on the other hand, extended eastward along the westward electrojet.

show abstract

< normald {boldJ}_{eq} / normald t > = < normald J_{eq, x} / normald t > boldx + < normald J_{eq, y} / normald t > boldy

< | d {boldJ}_{eq} / normald t | > = < \sqrt{{(normald J_{eq, x} / normald t)}^{2} + {(normald J_{eq, y} / normald t)}^{2}} >

< normald | {boldJ}_{eq} | / normald t > = < normald \sqrt{J_{eq, x}^{2} + J_{eq, y}^{2}} / normald t >

< {boldJ}_{eq} > = < J_{eq, x} > boldx + < J_{eq, y} > boldy

< | {boldJ}_{eq} | > = < \sqrt{J_{eq, x}^{2} + J_{eq, y}^{2}} >

…”

Section: Methodsmentioning

confidence: 99%

Solar wind control of ionospheric equivalent currents and their time derivatives

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is known to be a year of particularly strong space weather activity (see e.g. Juusola et al, 2015). Geomagnetic activity is strong particularly during 2-3 years after the solar maxima (Nevanlinna and Pulkkinen, 1998).…”

Section: Resultsmentioning

confidence: 99%

Sodankylä ionospheric tomography data set 2003–2014

Norberg

Roininen

Kero

et al. 2016

Geosci. Instrum. Method. Data Syst.

View full text Add to dashboard Cite

Abstract. Sodankylä Geophysical Observatory has been operating a receiver network for ionospheric tomography and collecting the produced data since 2003. The collected data set consists of phase difference curves measured from COS-MOS navigation satellites from the Russian Parus network (Wood and Perry, 1980) and tomographic electron density reconstructions obtained from these measurements. In this study vertical total electron content (VTEC) values are integrated from the reconstructed electron densities to make a qualitative and quantitative analysis to validate the long-term performance of the tomographic system. During the observation period, 2003-2014, there were three to five operational stations at the Fennoscandia sector. Altogether the analysis consists of around 66 000 overflights, but to ensure the quality of the reconstructions, the examination is limited to cases with descending (north to south) overflights and maximum elevation over 60 • . These constraints limit the number of overflights to around 10 000. Based on this data set, one solar cycle of ionospheric VTEC estimates is constructed. The measurements are compared against the International Reference Ionosphere (IRI)-2012 model, F10.7 solar flux index and sunspot number data. Qualitatively the tomographic VTEC estimate corresponds to reference data very well, but the IRI-2012 model results are on average 40 % higher than that of the tomographic results.

show abstract

“…(17,35,(95)(96)(97) It is important to note that the ionospheric current systems that couple to GICs are very structured, and are most intense at relatively high latitudes in the vicinity of the auroral ovals. The aurora and associated current systems descend in latitude during strong geomagnetic storms.…”

Section: Power Gridsmentioning

confidence: 99%

“…The aurora and associated current systems descend in latitude during strong geomagnetic storms. Consequently, impacts are not restricted to high latitudes (48,(98)(99)(100)(101) and have been documented in the United Kingdom, (17,43,102) Finland, (95,103) Sweden, (50) Spain, (104) the United States and Canada, (42) South Africa, (100,105,106) Japan, (107) China, (108) and Brazil. (109) The impact of geomagnetic storms on the North American power grid has been the subject of multiple reviews.…”

Section: Power Gridsmentioning

confidence: 99%

The Economic Impact of Space Weather: Where Do We Stand?

et al. 2017

View full text Add to dashboard Cite

Space weather describes the way in which the Sun, and conditions in space more generally, impact human activity and technology both in space and on the ground. It is now well understood that space weather represents a significant threat to infrastructure resilience, and is a source of risk that is wide-ranging in its impact and the pathways by which this impact may occur. Although space weather is growing rapidly as a field, work rigorously assessing the overall economic cost of space weather appears to be in its infancy. Here, we provide an initial literature review to gather and assess the quality of any published assessments of space weather impacts and socioeconomic studies. Generally speaking, there is a good volume of scientific peer-reviewed literature detailing the likelihood and statistics of different types of space weather phenomena. These phenomena all typically exhibit "power-law" behavior in their severity. The literature on documented impacts is not as extensive, with many case studies, but few statistical studies. The literature on the economic impacts of space weather is rather sparse and not as well developed when compared to the other sections, most probably due to the somewhat limited data that are available from end-users. The major risk is attached to power distribution systems and there is disagreement as to the severity of the technological footprint. This strongly controls the economic impact. Consequently, urgent work is required to better quantify the risk of future space weather events.

show abstract

High‐latitude ionospheric equivalent currents during strong space storms: Regional perspective

Cited by 36 publications

References 47 publications

Solar wind control of ionospheric equivalent currents and their time derivatives

Solar wind control of ionospheric equivalent currents and their time derivatives

Sodankylä ionospheric tomography data set 2003–2014

The Economic Impact of Space Weather: Where Do We Stand?

Contact Info

Product

Resources

About