dlr-logo swaci-logo logo-mv


 License Agreement

printable version

Currently the SWACI services are migrated to the Ionosphere Monitoring and Prediction Center (IMPC). This may cause downtimes of several products or parts of this webpage. To get latest news and product updates please visit impc.dlr.de!

Equivalent Slab Thickness / F2 Layer Critical Frequency

Equivalent slab thickness

The equivalent slab thickness is a measure of the width of the shape of the vertical electron density profile of the ionosphere. The equivalent slab thickness is defined by the ratio of the total electron content (TEC) and the peak electron density of the local ionosphere. To compute the peak electron density, vertical sounding data from different ionosonde stations are used. The corresponding TEC data are extracted from the SWACI TEC maps.


Usage of the equivalent slab thickness for ionosphere monitoring is described in e.g.:


N. Jakowski, S.M. Stankov, V. Wilken, C. Borries, D. Altadill, J. Chum, D. Buresova, J. Boska, P. Sauli, F. Hruska, Lj.R. Cander, Ionospheric behavior over Europe during the solar eclipse of 3 October 2005, Journal of Atmospheric and Solar-Terrestrial Physics, Volume 70, Issue 6, April 2008, Pages 836-853, ISSN 1364-6826, doi: http://dx.doi.org/10.1016/j.jastp.2007.02.016.


Gerzen, T., Jakowski, N., Wilken, V., and Hoque, M. M.: Reconstruction of F2 layer peak electron density based on operational vertical total electron content maps, Ann. Geophys., 31, 1241-1249,

doi: http://dx.doi.org/10.5194/angeo-31-1241-2013.


The plots below show on the left hand side the measurements of peak electron density foF2 and TEC and on the right hand side the derived slab thickness tau and the peak density hight hmF2.

Tromso (69.6°N; 19.2°E)

                                           Vertical Sounding Data supplied by University of Tromso

Juliusruh (54.4°N; 13.4°E)

                                                  Vertical Sounding Data supplied by IAP Kühlungsborn

Pruhonice (49.1°N, 14.1°E)

Vertical Sounding Data supplied by Ionospheric observatory Pruhonice of the Institute of Atmospheric Physics ASCR

< SWACI Products