Web Content Display Web Content Display
ESA SSA SWE Service Page Mockup: TIO/for

Transionospheric Radiolink - Monitoring and Forecast of Ionospheric Disturbances

Equivalent Slabthickness at Pruhonice
Equivalent Slabthickness at Pruhonice (Czech Republic), provided by Ionosphere Monitoring and Prediction Center (IMPC), DLR.

The service "Transionospheric Radiolink - Monitoring and Forecast of Ionospheric Disturbances" aims to provide an estimate of the occurrence risk of ionospheric disturbances, including monitoring and detection of ionospheric phenomena causing local disturbances of electron density and detection of geomagnetic storms. This service is currently under development. The aim is to consider the following ionospheric phenomena:

  • trough,
  • Travelling Ionospheric Disturbances (TIDs),
  • patches,
  • depletions and
  • D-region absorption.

Currently, this service provides vertical TEC maps, URSI ionospheric parameters and ionospheric perturbation products like the equivalent slab thickness and Rate Of Change of TEC Index (ROTI).

This service is implemented through a combination of products, tools and alerts which can be found through the following tabs along with expert support provided by the teams constituting the SWE Network. Should you require further guidance in the use of this service, or have specific questions about any aspects of the service presented here, don't hesitate to contact the Helpdesk.

The service is implemented through the following set of assets:

  • Ionosphere Monitoring and Prediction Center (IMPC) provided by the German Aerospace Center (DLR);
  • Real-Time Ionosphere Monitor (RTIM) provided by the Norwegian Mapping Authority (NMA);
  • European Ionosonde Service (EIS) provided by National Observatory of Athens (NOA);
  • Service Supporting Resource Exploitation System Operators (RESOSS) provided by he Tromsø Geophysical Observatory (UiT) and the Norwegian Mapping Authority (NMA);
  • Finnish Meteorological Institute (FMI) and Universitat Politècnica de Catalunya (UPC) providing services developed in the ESA activity MONITOR;
  • Ionospheric Scintillation Monitoring (ISM) developed by Collecte Localisation Satellites (CLS) and IEEA;
  • Swarm Utilisation Analysis (SUA) provided by GFZ German Research Centre for Geosciences;
  • ESA/ESOC Ionosphere Monitoring Facility, IONMON.

This service page is curated by the ESC Ionospheric Weather. For further information, please contact SSCC Help-desk


While quiet ionospheric conditions are considered in many applications, disturbed conditions limit the functionality and availability of most systems. Prominent ionospheric perturbations are e.g.

  • The ionospheric trough: an electron density depletion near the auroral region.
  • Ionospheric patches: very localised regions with strong electron density deviations. Patches occur predominantly in the polar regions.
  • Travelling Ionospheric Disturbances (TID): TIDs are signatures of atmospheric gravity waves. The atmospheric waves cause perturbations in the winds and density of the thermosphere, which is impacting the electron density.
  • Depletions: Electron density depletions in mid-latitudes often occur during high geomagnetic activity. They are related to mid-latitude spread-F plumes (or plasma bubbles).
  • D-region absorption: the D-region describes the lower ionosphere at about 80 km altitude. Enhancement of the D-region electron density can cause absorption of high frequency (HF) radio waves used for long-range communication. These D-region electron density enhancements can be primarily attributed to solar flares (X-ray) and radiation storms.


Many radiofrequency applications use models and assumptions of a quiet ionosphere. Sudden or dramatic changes in the electron density impact the functionality of these applications. E.g. ionospheric perturbations can disrupt or modify the radio communication used in aviation, military, emergency applications and by amateur radio operators. The forecasts of ionospheric perturbations can warn many users to take care of a limited functionality of their systems. The monitoring of ionospheric perturbations can be used to provide improved ionospheric corrections for some application.

Key Products

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 the Pruhonice ionosonde stations is used. The corresponding TEC data are extracted from the TEC maps.


ROT (Rate of change of TEC) is derived from the first derivative of TEC with respect to time. It is proposed as useful tool to monitor small-scale variability. The Rate of change of TEC index (ROTI) is defined as standard deviation of ROT. In the service provided here, ROTI is generated from ground based real-time data streams. The calculated values are associated to the ionospheric pierce points. ROTI is a good indicator for scintillations.

ROTI maps are provided by IMPC and RTIM. Within the RESOSS application, ROTI at the ground is provided. This product shows ROTI for a specified ground receiver location, which is easier to apply for users.

Additionally, the SUA activity provides ROT along the flight paths' of the three Swarm satellites.

Current ionospheric conditions

A common measure for the quiet time ionosphere are median values of the ionosphere during one solar rotation period (27 days). The deviation of the ionosphere from the quiet values (median) are considered as ionospheric perturbations.

The service provides a map of Europe presenting the current level of ionospheric activity (perturbations of foF2). It shows the deviation of the observed foF2 parameter in respect to the running 30 days median. The maps are published with a latency of 15 min.

Solar Flare detectors SISTED and GSFLAI developed in the MONITOR project

Solar flares cause plasma density enhancements in the ionosphere. These immediate electron density perturbations are detected by the following two products:

  • The MONITOR product SISTED is monitoring simultaneous sudden enhancements in the ionospheric Total Electron Content (TEC) using the drift rate (second time derivative) of the ionospheric carrier phase product (LI) which can be derived from the GNSS signal. LI is linearly related to the Slant TEC (STEC) along the satellite-receiver ray path under consideration. The drift rate is used to generate a set of three Impact Parameters (IP). An IP tells (in %) how many satellite-receiver pairs are affected by abrupt over ionisation.
  • The MONITOR product GSFLAI based on the impact of ionospheric electron content as response to solar flare activity. The ionospheric response appears as a change in Vertical TEC whose time derivative has a linear dependency on the cosine of Solar Zenith Angle. This relationship can be used to create a proxy for the time derivative of Solar EUV flux (in the spectral band of 21-34 nm). Validation studies with direct Solar EUV measurements by the SOHO SEM instrument (X-class flares during the years 2001-2011) have shown that the GSLAI proxy for EUV flux rate is accurate particularly during moderate and strong activity.


For further information, please contact SSCC Help-desk

The following products are associated with this service:

Ionospheric Disturbances nowcast

Ionospheric Disturbances
  • Equivalent slab thickness, Juliusruh
  • Equivalent slab thickness, Pruhonice
  • GIVE maps (northern Europe)
  • ROTI maps (northern Europe)
  • ROTI@Ground maps (Fennoscandia)
  • Alerts for ionospheric disturbances in the European sector
  • Current ionospheric conditions at each ionosonde location
  • ROTI maps for Europe
  • ROTI at ground time series (selected locations in northern Europe)
  • Swarm Rate Of change of TEC (ROT)
  • Swarm Ionospheric Bubble Index (IBI)

Ionosphere nowcast and forecast

Vertical Total Electron Content Map
  • TEC map (Europe), current
  • TEC map (Europe), 1hr forecast
  • TEC map (Global), current
  • TEC map (Global), 1hr forecast
  • VTEC maps (northern Europe)
  • Near real-time TEC maps for the European region
  • IONMON TEC maps
  • TEC and Err(TEC) nowcast modelled maps
  • TEC and Err(TEC) 6-hour forecast modelled maps
  • TEC and Err(TEC) nowcast modelled values at a given location
  • TEC and Err(TEC) 6h forecast modelled values at a given location
  • Swarm Total Electron Content (TEC)
3D Electron Density Grids
  • Swarm electron density (Ne)
URSI Ionospheric Parameters
  • European maps of foF2 long term predictions
  • Nowcast European maps of foF2
  • Maps of forecasted foF2 over Europe for the next 24 hours
  • Forecasted foF2 values for the next 24 hours over each ionosonde
Riometer Data
    Scintillation Indices and Parameters
    • S4 maps (northern Europe)
    • σφ maps (northern Europe)
    • Local scintillation indices S4 & σφ Kiruna
    • Local scintillation indices S4 & σφ Neustrelitz
    • Local scintillation indices S4 & σφ Svalbard
    • Local scintillation indices S4 & σφ Tenerife
    • Local scintillation indices S4 & σφ Toulouse
    • S4 and Err(S4) nowcast modelled maps
    • SigmaPhi and Err(SigmaPhi) nowcast modelled maps
    • S4 and Err(S4) 6-hour forecast modelled maps
    • SigmaPhi and Err(SigmaPhi) 6-hour forecast modelled maps
    • S4 and Err(S4) nowcast modelled values at a given location
    • SigmaPhi and Err(SigmaPhi) nowcast modelled values at a given location
    • S4 and Err(S4) 6h forecast modelled values at a given location
    • SigmaPhi and Err(SigmaPhi) 6h forecast modelled values at a given location

    Solar indices nowcast and forecast

    Smoothed Sunspot Number (SSN, R12)
      Solar Microwave Index (F10.7)
      • SIDC Latest 10.7cm Solar radio flux (F10.7) forecast
      Solar Flares
      • UGraz/KSO Latest Solar flare detections
      • SIDC Latest daily space weather bulletin
      • SIDC Latest Solar flare forecast
      • A-EFFort Solar flare forecast
      Solar X-ray Flux
      • Proba2/LYRA Rescaled latest data
      Solar EUV Integrated Flux
        Solar UV Flux

          Geomagnetic indices nowcast and forecast

          Local External Magnetic Field on Ground
          • Magnetogrammes from North(west) Europe and Greenland
          • Forecasts of dB/dt
          • Real-time and historic geomagnetic activity plots and data files for geomagnetic surveying (total field)
          • Real-time and historic geomagnetic activity plots and data files for directional drilling (total field, declination and inclination)
          Local Geomagnetic Induced Geoelectric Field
          • Maps for power and pipeline operators
          • Table of modelled GIC
          • Pipe-to-soil voltage (PSV)

          Tools associated with this service:

          The AMDA system provides an archive of planetary, solar wind, Earth magnetosphere and ionosphere mission and ground based products. In addition it supports a range of standard models such as magnetic footprints, magnetic fields, solar wind propagation to planets and probes as well as access to external databases of observations and simulations. A key functionality of the system is its embedded plotting, data mining and cataloguing functionalities which are extremely useful in relation to posteriori analysis.

          SWE Data is a web application that provides access to a wide range of Space Weather related data sources covering the areas of the spacecraft, ionospheric, and ground effects. SWE Data allows the user to access all data contained in the repository providing analysis and visualisation tools from these disparate sources.

          Alerts associated with this service:

          Ionospheric Disturbance Detection

          Alerts for ionospheric disturbances in the European sector


          This section provides links to web pages or resources that are not part of the SSA Space Weather Network or esa.int domain. These sites are not under ESA control and therefore ESA is not responsible for any of the information or links that you may find there.

          Other European Ionosphere Services

          Reference documents