The equatorial ionospheric response over Tirunelveli to the 15 January 2010 annular solar eclipse: observations

Abstract. In this paper we present a case study of the annular solar eclipse effects on the ionization of E and F regions of equatorial ionosphere over Tirunelveli [77.8° E, 8.7° N, dip 0.4° N] by means of digital ionosonde on 15 January 2010. The maximum obscuration of the eclipse at this station was 84% and it occurred in the afternoon. The E and F1 layers of the ionosphere showed very clear decrease in their electron concentrations, whereas the F2 layer did not show appreciable changes. A reduction of 30% was observed in the foF1 during the maximum phase of the eclipse. During the beginning phase of the eclipse, an enhancement of 0.97 MHz was observed in the foF2 as compared to that of the control days. But the foF2 decreased gradually as the eclipse progressed and a decrease of 0.59 MHz was observed towards the end phase of the eclipse. Observed variations in the h'F2 and hmF2 showed lower values than the control days, although hmF2 was found to increase a bit during the eclipse. Observed variability in the E, F1 and F2 layer ionospheric parameters on the eclipse day and their departure from the control days are discussed as the combined effect of annular eclipse and presence of counter equatorial electrojet (CEEJ).

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Ionospheric Response to the 21 May 2012 Annular Solar Eclipse Over Taiwan

Journal of Geophysical Research Space Physics ◽

10.1029/2018ja025928 ◽

2019 ◽

Vol 124 (5) ◽

pp. 3623-3636 ◽

Cited By ~ 4

Author(s):

J. Y. Liu ◽

S. S. Yang ◽

P. K. Rajesh ◽

Y. Y. Sun ◽

J. Chum ◽

...

Keyword(s):

Solar Eclipse ◽

Ionospheric Response ◽

Annular Solar Eclipse

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Impact of Annular Solar Eclipse of 15 January 2010 on the Atmospheric Boundary Layer Characteristics Over Thumba: A Case Study

Pure and Applied Geophysics ◽

10.1007/s00024-011-0336-9 ◽

2011 ◽

Vol 169 (4) ◽

pp. 741-753 ◽

Cited By ~ 6

Author(s):

D. Bala Subrahamanyam ◽

T. J. Anurose ◽

Mannil Mohan ◽

M. Santosh ◽

N. V. P. Kiran Kumar ◽

...

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Solar Eclipse ◽

Annular Solar Eclipse

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Temperature perturbations in the troposphere-stratosphere over Thumba (8.5° N, 76.9° E) during the solar eclipse 2009/2010

Annales Geophysicae ◽

10.5194/angeo-29-275-2011 ◽

2011 ◽

Vol 29 (2) ◽

pp. 275-282 ◽

Cited By ~ 8

Author(s):

K. V. Subrahmanyam ◽

G. Ramkumar ◽

K. K. Kumar ◽

D. Swain ◽

S. V. Sunil Kumar ◽

...

Keyword(s):

Solar Eclipse ◽

Lower Stratosphere ◽

Atmospheric Temperature ◽

Dynamical Response ◽

Delayed Effect ◽

Maximum Phase ◽

Partial Solar Eclipse ◽

Tropical Tropopause ◽

The Difference ◽

Annular Solar Eclipse

Abstract. Measurements of atmospheric temperature profiles in the troposphere and lower stratosphere were made over Thumba Equatorial Rocket Launching Station (TERLS) (8.5° N, 76.9° E) during a partial solar eclipse (22 July 2009) and an annular solar eclipse (15 January 2010). It was observed that during the partial solar eclipse, the temperature decreased by 2–3 °C in the vicinity of the tropopause and in the lower stratosphere the temperature increased by ~2.6 °C during the maximum phase of the partial solar eclipse. During the annular solar eclipse, a temperature reduction of ~2 °C was observed around the tropopause. This study also revealed a feature of delayed effect in the form of a very intense warming of ~8 °C at 18 km after about 4 h of the annular solar eclipse. The Cold-Point Tropopause (CPT) temperature increased slowly before the beginning of the eclipse (up to 10:00 IST) and during the maximum phase of the eclipse, the difference in CPT temperature and height was −3.5 °C and ~110 m, respectively, as that of the control day. After the four hours of the eclipse, the CPT height had decreased by ~1.7 km and the CPT temperature increased by ~4.6 °C. This is for the first time that the diurnal variation of the tropopause has been reported during a solar eclipse day. The present study, thus, provided an opportunity to investigate the temperature perturbations in the troposphere and lower stratosphere during a partial and annular solar eclipse. The highlight of the present results are (1) cooling of the entire troposphere and lower stratosphere during the maximum phase of annular solar eclipse, (2) an intense heating of the lower stratosphere by 8 °C after nearly four hours from the maximum phase of the annular eclipse, and (3) drastic variations in the diurnal evolution of the tropical tropopause characteristics. The cooling effect is attributed to the radiative response of the atmosphere to the solar eclipse, where as heating is attributed to the dynamical response of the atmosphere to the solar eclipse. These results may have important implications in understanding the response of the atmosphere to the radiative, as well as dynamical, perturbations caused by any celestial or terrestrial disturbances.

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

Annales Geophysicae ◽

10.5194/angeo-26-107-2008 ◽

2008 ◽

Vol 26 (1) ◽

pp. 107-116 ◽

Cited By ~ 61

Author(s):

H. Le ◽

L. Liu ◽

X. Yue ◽

W. Wan

Keyword(s):

Theoretical Model ◽

Solar Radiation ◽

Solar Eclipse ◽

Ionospheric Disturbance ◽

Low Latitude ◽

Ionospheric Response ◽

Latitude Range ◽

Eclipse Observations ◽

E Region ◽

Low Latitude Ionosphere

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, FR, 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.

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