Morphology of NmF2 nighttime increases in the Eurasian sector

Михайлов, А. В.; Leschinskaya, T. Yu.; Förster, M.

doi:10.1007/s005850000214

Cited by 6 publications

(6 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[29] Several theories have been proposed in the literature as possible explanations of the maintenance and increases of the nighttime ionosphere [e.g., Mikhailov et al, 2000;Pavlov and Pavlova, 2005]. Arendt and Soicher [1964] stated that the increase is due to ionization drifts from ionospheric regions above 1000 km into regions below it.…”

Section: Discussionmentioning

confidence: 99%

“…[3] Lots of investigations have been conducted extensively to study the nighttime enhancements either in total electron content [e.g., Arendt and Soicher, 1964;Titheridge, 1968;Young et al, 1970;Davies et al, 1979;Rao, 1984, 1987;Balan et al, 1994;Horvath, 2006;Unnikrishnan et al, 2002;Chen et al, 2008;Jain et al, 2011;Trivedi et al, 2013] or in critical frequency (foF2) or peak electron density (NmF2) of the F2 layer [Farelo et al, 2002;Tsagouri and Belehaki, 2002;Mikhailov et al, 2000;Pavlov and Pavlova, 2007;Yakovets et al, 2009;Pezzopane et al, 2011;Pirog et al, 2011] or in both of them [Essex and Klobuchar, 1980;Jakowski et al, 1991;Gordienko et al, 2001]. Moreover, observations from incoherent scatter radars [Pavlov and Pavlova, 2005], tomographic images [Dabas and Kersley, 2003], and radio occultations [Luan et al, 2008;He et al, 2009] have also been analyzed to reveal features and physical processes involved in the enhancement phenomena.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A case study of postmidnight enhancement in F‐layer electron density over Sanya of China

et al. 2013

View full text Add to dashboard Cite

[1] The electron density in the ionospheric F region occasionally stops its decay and rises pronouncedly during night hours, which are termed ionospheric nighttime enhancements. In this case study, we analyzed the manually scaled ionogram records measured by a Lowell DPS-4D ionosonde operated at Sanya (18.3°N, 109.6°E), China, to explore postmidnight enhancement events occurred in 2012, a year of moderate solar activities. Common features in these cases illustrate that, accompanying nighttime rises in peak electron density of F2 layer (NmF2), the height of F2 layer is depressed significantly, and the ionogram-derived electron density height profiles become thinner. There are time shifts in the development of electron density enhancements in the F layer; that is, enhancement develops earlier and reaches peaks earlier at higher altitudes than at lower altitudes. Meanwhile, plasma drift is detected downward under such events, revealing the essential role of the westward electric field in forming the postmidnight enhancements in electron density of ionospheric F layer at such low latitudes.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A case study of postmidnight enhancement in F‐layer electron density over Sanya of China

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The electron temperature in the lunar shadow should drop rapidly to break the diffusive equilibrium of the middle latitude ionosphere. Thus, it may result in the downward ionization diffusion from the protonsphere [Evans, 1965b;Jakowski and Förster, 1995;Mikhailov et al, 2000]. The plasma flux will make up the electron loss, delay the ionospheric response to the solar eclipse, and even cause the electron density enhancement [Evans, 1965a;Jakowski et al, 2008;Chen et al, 2013].…”

Section: 1002/2014ja020849mentioning

confidence: 99%

Plasma flux and gravity waves in the midlatitude ionosphere during the solar eclipse of 20 May 2012

Chen

Huang

et al. 2015

JGR Space Physics

View full text Add to dashboard Cite

The solar eclipse effects on the ionosphere are very complex. Except for the ionization decay due to the decrease of the photochemical process, the couplings of matter and energy between the ionosphere and the regions above and below will introduce much more disturbances. Five ionosondes in the Northeast Asia were used to record the midlatitude ionospheric responses to the solar eclipse of 20 May 2012. The latitude dependence of the eclipse lag was studied first. The f o F 2 response to the eclipse became slower with increased latitude. The response of the ionosphere at the different latitudes with the same eclipse obscuration differed from each other greatly. The plasma flux from the protonsphere was possibly produced by the rapid temperature drop in the lunar shadow to make up the ionization loss. The greater downward plasma flux was generated at higher latitude with larger dip angle and delayed the ionospheric response later. The waves in the f o E s and the plasma frequency at the fixed height in the F layer are studied by the time period analytic method. The gravity waves of 43-51 min center period during and after the solar eclipse were found over Jeju and I-Cheon. The northward group velocity component of the gravity waves was estimated as~108.7 m/s. The vertical group velocities between 100 and 150 km height over the two stations were calculated as~5 and~4.3 m/s upward respectively, indicating that the eclipse-induced gravity waves propagated from below the ionosphere.

show abstract

“…Jakowski et al [1991] and Mikhailov et al [2000a] showed that the occurrence of enhancement is more in winter in solar minimum and summer in solar maximum. Mikhailov et al [2000b] reported that the frequency of occurrence in the postmidnight enhancement is more in winter season, and the pattern is mostly independent of solar activity.…”

Section: Introductionmentioning

confidence: 99%

Morphology of midlatitude electron density enhancement using total electron content measurements

et al. 2016

View full text Add to dashboard Cite

Using the global ionospheric map of total electron content in 2002–2009, this paper investigates anomalous, midlatitude electron density enhancement (MEDE) bounded by a tropical electron density trough and the usual midlatitude electron density trough at all times (24 h) of the day for the first time. The diurnal, seasonal, and longitudinal variations in the occurrence and strength of MEDE are studied at solar maximum (2002) and long deep solar minimum (2009), and latitude‐longitude dependence is examined using the data in 2002–2009. The results show that the MEDE occurs at all times of the day though pronounced at night (2200–0400 LT), and in some cases the daytime occurrence could be more frequent than the corresponding nighttime occurrence. The strength maximizes at around 0400 LT and is weak during daytime. Both the occurrence and strength are, in general, predominant in winter at low solar activity and exhibit significant longitudinal dependence. The E × B drift, strength, and direction of neutral wind and ionosphere‐plasmasphere plasma flow and their day‐to‐day variations are suggested to account for the existence of MEDE at all times of the day.

show abstract

Morphology of NmF2 nighttime increases in the Eurasian sector

Cited by 6 publications

References 8 publications

A case study of postmidnight enhancement in F‐layer electron density over Sanya of China

A case study of postmidnight enhancement in F‐layer electron density over Sanya of China

Plasma flux and gravity waves in the midlatitude ionosphere during the solar eclipse of 20 May 2012

Morphology of midlatitude electron density enhancement using total electron content measurements

Contact Info

Product

Resources

About