An<i>F</i>region eclipse

Evans, J. V.

doi:10.1029/jz070i001p00131

Cited by 108 publications

(72 citation statements)

References 16 publications

(15 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In addition, calculations show that ion temperature (not shown) also has a slight decrease of 100-200 K at heights above 600 km, whereas there is a slight decrease of less than 100 K at heights below 600 km. There are many similar reports about a large decrease in electron temperature and a smaller decrease in ion temperature derived from measurements and simulations as a consequence of the eclipse in the past (Evans, 1965a;Stubbe, 1970;Salah et al, 1986;Roble et al, 1986;Boitman et al, 1999). The calculated relative change in the ion drift velocity parallel to the magnetic field line is shown in Fig.…”

Section: Ionospheric Response At the Time Of Maximum Eclipsementioning

confidence: 89%

The ionospheric responses to the 11 August 1999 solar eclipse: observations and modeling

Liu

Yue

et al. 2008

Ann. Geophys.

View full text Add to dashboard Cite

Abstract.A total eclipse occurred on 11 August 1999 with its path of totality passing over central Europe in the latitude range 40 • -50 • N. The ionospheric responses to this eclipse were measured by a wide ionosonde network. On the basis of the measurements of foE, foF1, and foF2 at sixteen ionosonde stations in Europe, we statistically analyze the variations of these parameters with a function of eclipse magnitude. To model the eclipse effects more accurately, a revised eclipse factor, F R , is constructed to describe the variations of solar radiation during the solar eclipse. Then we simulate the effect of this eclipse on the ionosphere with a mid-and low-latitude ionosphere theoretical model by using the revised eclipse factor during this eclipse. Simulations are highly consistent with the observations for the response in the E-region and F1-region. Both of them show that the maximum response of the mid-latitude ionosphere to the eclipse is found in the F1-region. Except the obvious ionospheric response at low altitudes below 500 km, calculations show that there is also a small response at high altitudes up to about 2000 km. In addition, calculations show that when the eclipse takes place in the Northern Hemisphere, a small ionospheric disturbance also appeared in the conjugate hemisphere.

show abstract

Section: Ionospheric Response At the Time Of Maximum Eclipsementioning

confidence: 89%

The ionospheric responses to the 11 August 1999 solar eclipse: observations and modeling

Liu

Yue

et al. 2008

Ann. Geophys.

View full text Add to dashboard Cite

show abstract

“…A still relevant publication is the collection of papers by Beynon and Brown [ 1956]. More recent observations have been reported, for example, by Evans [ 1965], $alah et al [ 1986], or Cheng et al [ 1992]. They all find a reduction of electron density in the ionospheric E and F1 regions.…”

Section: Introductionmentioning

confidence: 87%

Did the solar eclipse of August 11, 1999, show a geomagnetic effect?

Korte¹,

Lühr²,

Förster³

et al. 2001

J. Geophys. Res.

View full text Add to dashboard Cite

Abstract. The solar eclipse of August 11, 1999, presented good conditions for the study of associated geophysical effects. Ionospheric measurements clearly show a decrease of electron density due to the reduced solar irradiation during the eclipse. However, contrary to claims elsewhere, the decreased conductivity did not cause an obvious effect in the geomagnetic recordings at the Earth's surface. Recordings of several European geomagnetic observatories and of a temporary variometer network, set up specially to observe an eclipse effect in detail, have been studied directly and in terms of equivalent currents in the ionosphere. We present the results of these studies and discuss possible current configurations that might explain the lack of an eclipse effect in geomagnetic recordings.

show abstract

“…However, electron temperature drops more quickly than ions (Evans, 1965), leading to decreased ratio of electron-ion temperature and acceleration of downward diffusion of electrons from the topside ionosphere (Yeh et al, 1997). The electrons reaching the lower altitudes are lost through the recombination process.…”

Section: Annmentioning

confidence: 99%

“…Usually a large amount of decrease in the electron density at lower altitudes (below F1 layer) is observed (Salah et al, 1986;Le et al, 2008), whereas in the F2 region altitude, an increase (Evans, 1965;Salah et al, 1986;Le et al, 2010) and decrease Jakowski et al, 2008) in the electron density are reported. The different behavior of F2 layer arises due to the fact that the electron density is more controlled by the transport process than by the production rate.…”

Section: Introductionmentioning

confidence: 99%

Ionospheric response to total solar eclipse of 22 July 2009 in different Indian regions

Kumar

Singh

2013

Ann. Geophys.

View full text Add to dashboard Cite

The variability of ionospheric response to the total solar eclipse of 22 July 2009 has been studied analyzing the GPS data recorded at the four Indian low-latitude stations Varanasi (100% obscuration), Kanpur (95% obscuration), Hyderabad (84% obscuration) and Bangalore (72% obscuration). The retrieved ionospheric vertical total electron content (VTEC) shows a significant reduction (reflected by all PRNs (satellites) at all stations) with a maximum of 48% at Varanasi (PRN 14), which decreases to 30% at Bangalore (PRN 14). Data from PRN 31 show a maximum of 54% at Kanpur and 26% at Hyderabad. The maximum decrement in VTEC occurs some time (2–15 min) after the maximum obscuration. The reduction in VTEC compared to the quiet mean VTEC depends on latitude as well as longitude, which also depends on the location of the satellite with respect to the solar eclipse path. The amount of reduction in VTEC decreases as the present obscuration decreases, which is directly related to the electron production by the photoionization process. The analysis of electron density height profile derived from the COSMIC (Constellation Observing System for Meteorology, Ionosphere & Climate) satellite over the Indian region shows significant reduction from 100 km altitude up to 800 km altitude with a maximum of 48% at 360 km altitude. The oscillatory nature in total electron content data at all stations is observed with different wave periods lying between 40 and 120 min, which are attributed to gravity wave effects generated in the lower atmosphere during the total solar eclipse

show abstract

AnFregion eclipse

Cited by 108 publications

References 16 publications

The ionospheric responses to the 11 August 1999 solar eclipse: observations and modeling

The ionospheric responses to the 11 August 1999 solar eclipse: observations and modeling

Did the solar eclipse of August 11, 1999, show a geomagnetic effect?

Ionospheric response to total solar eclipse of 22 July 2009 in different Indian regions

Contact Info

Product

Resources

About