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Partial Solar Eclipse on 4th January 2011


The first of four partial solar eclipses in 2011 occured on 4 January over the northern part of Africa, most of Europe and norhwestern Asia. The eclipse started at 8:16 UT and ended at 10:52 UT. The moon shadowed up to about 80%  of the solar disc. For more detailed information see NASA Web page: http://eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2011Jan04P.GIF


Due to lower solar illumination of the Earth’s atmosphere the photoionization is reduced, i.e. the ionsation level does not reach its average values or is even more reduced if loss processes dominate. We are able to show the behavior of the total ionospheric ionisation over Europe and on a global scale by near real time monitoring of the total electron content (TEC) of the ionosphere based on numerous GNSS measurements. SWACI uses GPS measurements from various GNSS networks such as International GNSS Service (IGS), EUREF and ascos distributed by BKG Frankfurt. The global TEC maps are mainly generated by data provided by the Real-Time Pilot Project of IGS (IGS-RTPP).


Here we present are animations of differential TEC maps obtained by subtracting 27 days medians from the actual TEC map values on 4 January 2011. This presentation enables the viewer to see clearly the ionisation loss due to the solar eclipse.

Furthermore, a solar eclipse can be considered as an active experiment with varying solar illumination. Therefore, such effects in the ionosphere have also been discussed earlier in DLR Neustrelitz, as can be found in:


Jakowski, N., Schlueter, S., Heise, S., Feltens, J., 1999. Satellite Technology Glimpses Ionospheric Response to Solar Eclipse, EOS, Transactions. American Geophysical Union, 80, 51, 21 December 1999.

Jakowski, N., Heise, S., Wehrenpfennig, A., Schlueter, S., 2001. Total electron content studies of the solar eclipse on 11 August 1999, CD-ROM, Proc. IBSS, Boston, 4-6 June, 2001, 279-283

Jakowski, N., S. M. Stankov, V. Wilken, C. Borries, D. Altadill, J. Chum, D. Buresova , J. Boska, P. Sauli,  H. Hruska, L. Cander, Ionospheric behaviour over Europe during the solar eclipse of 3 October 2005

Global20110104.zip    4.7 M
Global10h.avi    2.3 M

Europa20110104.zip    7.5 M
Europa24h.avi    2.8 M

Comparison of TEC and F2 layer critical frequency above the ionosonde station Juliusruh


Ionosonde parameters such as F2 layer critical frequency foF2 and peak density height hmF2 as measured at the ionosonde station Juliusruh of the Leibniz-Institut für Atmosphärenphysik e.V. (http://www.ionosonde.iap-kborn.de/ ) are combined with TEC data over Juliusruh in near real time. The derived equivalent slab thickness is a measure of the shape of the vertical electron density profile over Juliusruh.

The key parameters mentioned above and shown in the figures below indicate strong variations after sunrise, probably induced by the partial solar eclipse.