For the detection of Travelling Ionospheric disturbances, eight complementary methodologies are applied in the TechTIDE project with real-time and historical data from Digisonde DPS4D ionospheric sounders, from the Continuous Doppler Sounding System and from GNSS receivers.
- HF-TID method
- CDSS-MSTID detection method
- GNSS TEC gradient algorithms
- Spatial and Temporal GNSS analysis
- The AATR indicator
- HF Interferometry method
- HTI technique to monitor wave activity
- TaD 3D mapping of the electron density
3. GNSS TEC gradient algorithms
(Borries et al. 2017)
Large scale Travelling Ionospheric Disturbances (TIDs) occurring during geomagnetic storms produce strong temporal and spatial TEC gradients which are observed closest to the source region of LSTIDs. These gradients are attributed to heating and convection processes which are related to the excitation of LSTIDs [Borries et al. 2017]. Temporal and spatial gradients are calculated based on maps of TEC. Figure 5 presents the results of this method applied on the 20 November 2003 storm. The spatial TEC gradients (top panel) are derived from DLR TEC maps at 15°E. The TEC rate (bottom panel) is derived from DLR TEC maps at 15°E. The white line approximates the trough location. Large-scale TEC gradients are routinely produced by the DLR and the results will be used on TechTIDE for the real-time identification of LSTIDs and the identification of the source region.
Borries C., N. Jakowski, K. Kauristie, et al. (2017), On the dynamics of Large-Scale Travelling Ionospheric Disturbances over Europe on 20th November 2003, J. Geophys. Res., 122, doi:10.1002/2016JA023050.