IONMON Archive
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Description:
The ESA/ESOC Navigation Support Office delivers animations of Total Electron Content (TEC) & TEC Root Mean Square errors (RMS) global maps. Each animation covers 24 hours with a time resolution of 1-hour. TEC and RMS values are displayed in TEC units (1 TECU = 10¹⁶ el/m²) on the colour maps animations. The colour-bars values range is fixed within each animation. For a specific day, the upper limit of the colour-bar for TEC is set to be the maximum value found in all the TEC maps used to build the daily animation. The upper limit of the colour-bar for RMS is the average of the maximum 10% values found in all the RMS maps used to build the daily animation. The subsolar point is displayed in the animations as black dot.

TEC and RMS maps are computed with a single layer approach (IONMON Version 1), taking slant range TEC observables derived from dual-frequency Galileo, GPS, GLONASS, and BeiDou data, whereby ionospheric TEC is modelled by spherical harmonics in combination with a daily Differential Code Biases (DCBs) fitting. In this single layer approach, the ionospheric TEC is assumed to be condensed on a hollow sphere enveloping the Earth at an altitude of 450 km. On that sphere, the global TEC distribution is then described by a degree and order 15 spherical harmonics function. The function coefficients are determined from GNSS dual-frequency data recorded at maximum 300 globally distributed (typically 220 - 240) ground sites. Model-internal, all computations are conducted in a solar-geomagnetic reference system.

These movies are processed once per day, and new daily movies are typically available shortly after 10H UTC. Please note that a new processing scheme was implemented in September 2017, and movies prior to this date may not be fully consistent. For this reason, movies preceding this date are provided for illustrative purposes only, and should not considered definitive.

References:
Feltens, J. (2007), Development of a new three-dimensional mathematical ionosphere model at European Space Agency/European Space Operations Centre, Space Weather, 5, S12002, doi: 10.1029/2006SW000294.

Feltens, J., M. Angling, N. Jackson-Booth, N. Jakowski, M. Hoque, M. Hernández-Pajares, A. Aragón-Àngel, R. Orús, and R. Zandbergen (2011), Comparative testing of four ionospheric models driven with GPS measurements, Radio Sci., 46, RS0D12, doi: 10.1029/2010RS004584.

Acknowledgments:
This web page forms part of the European Space Agency's network of space weather services and service development activities, and is supported under ESA contract number 4000134036/21/D/MRP. For further product related information or enquiries contact the helpdesk. E-mail: helpdesk.swe@esa.int
All publications and presentations using data obtained from this site should acknowledge ESA and The ESA Space Safety Programme
For further information about space weather in the ESA Space Safety Programme see: www.esa.int/spaceweather
Access the ESA SWE Portal here: swe.ssa.esa.int