Welcome to the Transionospheric Radio Link - Monitoring and Forecast of Ionospheric Disturbances service

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

The service "Transionospheric Radio Link - 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 sections 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);
• GNSS Performance Indicator (GPI) provided by the German Aerospace Center (DLR);
• Warning and Mitigation Technologies for Travelling Ionospheric Disturbances Effects (TechTIDE) provided by National Observatory of Athens (NOA);
• Ionospheric determination and navigation based on Satellite And Terrestrial systems (IonSAT) provided by Universitat Politècnica de Catalunya (UPC);
• Ionospheric Scintillation Monitoring (ISM) developed by Collecte Localisation Satellites (CLS) and IEEA (currently under maintenance);
• Swarm Utilisation Analysis Ionosphere(SUA I) provided by the German Research Centre for Geosciences (GFZ);
• Swarm Utilisation Analysis Geomagnetic conditions (SUA G) provided by the German Research Centre for Geosciences (GFZ);
• ESA/ESOC Ionosphere Monitoring Facility, IONMON;
• Regional volumetric reconstructions of ionospheric electron density product TomoScand provided by the Finnish Meteorological Institute (FMI) and University of Oulu.

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

Introduction

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.

Application

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 and ROTI

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. RTIM also provides ROTI at the ground that 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

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

Auxiliary Information

This section provides links to web pages or resources that are not part of the ESA 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

• Space Weather Application Service - Ionosphere (SWACI), one of the first prototypes for a near-real-time ionosphere data service in Europe, has been established in 2005 by the German Aerospace Center. It is currently transferred into the operational service Ionosphere Monitoring and Prediction Center (IMPC)
• To better classify the ionosphere and forecast its disturbances over Europe, a data collection endeavour called the European Digital Upper Atmosphere Server (DIAS) was initiated in 2004 by a consortium formed around several European ionospheric stations that transmit in real-time ionospheric parameters automatically scaled. The DIAS project is a collaborative venture of eight institutions funded by the European Commission eContent Programme.

Reference documents

• ECSS-E-ST-10-04C Rev.1 Space environment (15 June 2020)

Contact

For further information, please contact SSCC Helpdesk.