Pre-storm electron density enhancements at middle latitudes

Burešová, Dalia; Laštovička, Jan

doi:10.1016/j.jastp.2008.01.014

Cited by 30 publications

(18 citation statements)

References 26 publications

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“…A large positive foF2 enhancement took place during daytime hours. That was a disturbed day and the analysis of his period, see later, in connection with the Buresova andLaštovička (2007, 2008) results.…”

Section: Analysis Of the Publicationsmentioning

confidence: 95%

“…Many ex- amples of isolated magnetic storms can be found which are not preceded by any pronounced auroral activity. More careful analysis has been performed by Buresova andLaštovička (2007, 2008), who analyzed 65 strong geomagnetic storms over the 1995-2005 period using midlatitude worldwide ionosonde observations. They have found the foF2 pre-storm enhancements for 15 events in Europe.…”

Section: Analysis Of the Publicationsmentioning

confidence: 99%

“…We have analyzed such successions for the periods listed in the paper by Buresova and Laštovička (2008) as well as for the extended list of dates. In accordance to our method, only daytime (11:00-14:00) LT hours were analyzed.…”

Section: Analysis Of the Publicationsmentioning

confidence: 99%

“…The problem of NmF2 pre-storm enhancements comes up from time to time in literature (Danilov et al, 1985;Danilov and Belik, 1992;Danilov, 2001;Kane, 2005;Buresova and Correspondence to: A. V. Mikhailov (avm71@orc.ru) Laštovička, 2007Liu et al, 2008;Blagoveschensky et al, 2006;Blagoveschensky and Kalishin, 2009). Both the morphology and plausible mechanisms are considered.…”

Section: Introductionmentioning

confidence: 99%

“…First of all, the very fact of such enhancements' existence should be established in relation to the following geomagnetic disturbances, i.e., are the two phenomena related or is this a coincidence and are the researchers wanting to see this relationship? According to Buresova andLaštovička (2007, 2008), only 20-25% of magnetic storms are accompanied by prestorm NmF2 enhancements. What kind of NmF2 increase may be considered as a pre-storm enhancement (its magnitude, duration and lead time) should be established.…”

Section: Introductionmentioning

confidence: 99%

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Pre-storm <I>Nm</I>F2 enhancements at middle latitudes: delusion or reality?

Mikhailov

Perrone

2009

Ann. Geophys.

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Abstract.A critical analysis of recent publications devoted to the NmF2 pre-storm enhancements is performed. There are no convincing arguments that the observed cases of NmF2 enhancements at middle and sub-auroral latitudes bear a relation to the following magnetic storms. In all cases considered the NmF2 pre-storm enhancements were due to previous geomagnetic storms, moderate auroral activity or they presented the class of positive quiet time events (Qdisturbances). Therefore, it is possible to conclude that there is no such an effect as the pre-storm NmF2 enhancement as a phenomenon inalienably related to the following magnetic storm. The observed nighttime NmF2 enhancements at subauroral latitudes may result from plasma transfer from the plasma ring area by meridional thermospheric wind. Enhanced plasmaspheric fluxes into the nighttime F2-region resulted from westward substorm-associated electric fields is another possible source of nighttime NmF2 enhancements. Daytime positive Q-disturbances occurring under very low geomagnetic activity level may be related to the dayside cusp activity.

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Section: Analysis Of the Publicationsmentioning

confidence: 95%

Section: Analysis Of the Publicationsmentioning

confidence: 99%

Section: Analysis Of the Publicationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Pre-storm <I>Nm</I>F2 enhancements at middle latitudes: delusion or reality?

Mikhailov

Perrone

2009

Ann. Geophys.

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A global scale picture of ionospheric peak electron density changes during geomagnetic storms

Kumar

Parkinson

2017

Space Weather

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Changes in ionospheric plasma densities can affect society more than ever because of our increasing reliance on communication, surveillance, navigation, and timing technology. Models struggle to predict changes in ionospheric densities at nearly all temporal and spatial scales, especially during geomagnetic storms. Here we combine a 50 year (1965–2015) geomagnetic disturbance storm time (Dst) index with plasma density measurements from a worldwide network of ~132 vertical incidence ionosondes to develop a picture of global scale changes in peak plasma density due to geomagnetic storms. Vertical incidence ionosondes provide measurements of the critical frequency of the ionospheric F2 layer (foF2), a direct measure of the peak electron density (NmF2) of the ionosphere. By dissecting the NmF2 perturbations with respect to the local time at storm onset, season, and storm intensity, it is found that (i) the storm‐associated depletions (negative storm effects) and enhancements (positive storm effects) are driven by different but related physical mechanisms, and (ii) the depletion mechanism tends to dominate over the enhancement mechanism. The negative storm effects, which are detrimental to HF radio links, are found to start immediately after geomagnetic storm onset in the nightside high‐latitude ionosphere. The depletions in the dayside high‐latitude ionosphere are delayed by a few hours. The equatorward expansion of negative storm effects is found to be regulated by storm intensity (farthest equatorward and deepest during intense storms), season (largest in summer), and time of day (generally deeper on the nightside). In contrast, positive storm effects typically occur on the dayside midlatitude and low‐latitude ionospheric regions when the storms are in the main phase, regardless of the season. Closer to the magnetic equator, moderate density enhancements last up to 40 h during the recovery phase of equinox storms, regardless of the local time. Strikingly, high‐latitude plasma densities are moderately enhanced for up to 60 h prior to the actual onset of storms during the equinoxes and summer; a potential precursor of a geomagnetic storm.

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Preliminary investigation of real‐time mapping of f_oF₂ in northern China based on oblique ionosonde data

et al. 2013

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[1] A real-time mapping model of f o F 2 in northern China was established using neural networks (NNs). To avoid the local minimum problem associated with traditional NNs, a newly improved genetic algorithm-based NN (GA-NN) was developed using the input parameters of solar activities, geomagnetic activities, neutral winds, seasonal information, and geographical coordinates. The f o F 2 data were extracted by inversing the oblique ionograms obtained from the oblique ionosondes of the China Ground-based Seismo-ionospheric Monitoring Network every 30 min for the period from August 2009 to December 2011. The data associated with five transmitter stations (Beijing, Changchun, Qingdao, Xinxiang, and Suzhou) and one receiver station in Binzhou were considered the input parameters for the real-time f o F 2 mapping model, and the data from the Dalian and Jinyang transmitter stations were used to verify the results. The Jining transmitter station data were used to test the capability of the model. The root-mean-square error and percent deviation were calculated to estimate the performance of the model. The correlation coefficient was used to evaluate the correlation of observed and predicted values. In addition, observations of f o F 2 from the vertical ionosondes at Beijing, Changchun, Qingdao, and Suzhou stations are compared with the model prediction of f o F 2 . The results indicate that the developed real-time f o F 2 mapping model based upon genetic algorithm-based NN is very promising for ionospheric studies.

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Pre-storm electron density enhancements at middle latitudes

Cited by 30 publications

References 26 publications

Pre-storm <I>Nm</I>F2 enhancements at middle latitudes: delusion or reality?

Pre-storm <I>Nm</I>F2 enhancements at middle latitudes: delusion or reality?

A global scale picture of ionospheric peak electron density changes during geomagnetic storms

Preliminary investigation of real‐time mapping of f_oF₂ in northern China based on oblique ionosonde data

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Pre-storm electron density enhancements at middle latitudes

Cited by 30 publications

References 26 publications

Pre-storm &lt;I&gt;Nm&lt;/I&gt;F2 enhancements at middle latitudes: delusion or reality?

Pre-storm &lt;I&gt;Nm&lt;/I&gt;F2 enhancements at middle latitudes: delusion or reality?

A global scale picture of ionospheric peak electron density changes during geomagnetic storms

Preliminary investigation of real‐time mapping of foF2 in northern China based on oblique ionosonde data

Contact Info

Product

Resources

About

Pre-storm <I>Nm</I>F2 enhancements at middle latitudes: delusion or reality?

Pre-storm <I>Nm</I>F2 enhancements at middle latitudes: delusion or reality?

Preliminary investigation of real‐time mapping of f_oF₂ in northern China based on oblique ionosonde data