Servicenavigation

Detailseite

Zurück

Projekt Druckansicht

Analyse von ionosphärischen-plasmasphärischen Variationen und Mechanismen über satellitenbasierende GNSS Messungen

Fachliche Zuordnung Physik und Chemie der Atmosphäre
Förderung Förderung von 2018 bis 2022
Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 392206641
 
Erstellungsjahr 2023

Zusammenfassung der Projektergebnisse

We developed a new three-dimensional electron density model called NEDM2020 to support space weather services and mitigate propagation errors for trans-ionospheric signals. A dedicated plasmasphere model (NPSM, Jakowski and Hoque 2018) is used for describing the correct representation of the topside ionosphere and plasmasphere in NEDM2020. Our investigation shows that the NEDM2020 performs better than the NeQuick2 when compared with the in-situ data from Van Allen Probes and ICON satellites and TEC data from COSMIC and TOPEX/Poseidon missions. For the first time, we developed a global model of the equivalent slab thickness (Neustrelitz equivalent Slab Thickness Model – NSTM). The equivalent slab thickness is defined by the ratio of the vertical total electron content over the peak electron density. It characterizes the width of vertical electron density profiles and is an important parameter for a better understanding of ionospheric processes under regular as well as under perturbed conditions. NSTM provides consistent results with the mid-latitude bulge (MLB) of the equivalent slab thickness, described for the first time in this paper. Furthermore, the model recreates quite well ionospheric anomalies such as the Night-time Winter Anomaly (NWA) which is closely related to the Mid-latitude Summer Night-time Anomaly (MSNA) like the Weddell Sea Anomaly (WSA) and Okhotsk Sea Anomaly (OSA). It is expected that the performance of the global empirical ionosphere models (e.g., IRI, NeQuick2, NEDM2020) can be improved by integrating NSTM into them. At certain geographic locations, especially in the polar regions, the ionization of the ionospheric E layer can dominate over that of the F2 layer. The associated electron density profiles show their ionization maximum at E layer heights between 80 and 150 km above the Earth’s surface. This phenomenon is called the “E layer dominated ionosphere” (ELDI). For the first time, we developed an empirical, climatological model that describes ELDI characteristics and occurrence probability. The developed Neustrelitz ELDI Event Model (NEEM) paves the way for future prediction of the ELDI and of its characteristics in technical applications, especially from the fields of telecommunications and navigation. Precision and safety of life applications of GNSS require key information on space weather conditions in particular on the perturbation degree of the ionosphere. Such systems are particularly vulnerable against severe spatial gradients and rapid changes of the TEC measured along different satellite-receiver links. To estimate the perturbation degree of the ionosphere instantaneously we developed the Gradient Ionosphere indeX (GIX) and the Sudden Ionospheric Disturbance indeX (SIDX). Real data tests confirm the applicability of GIX and SIDX to monitor spatial gradients and rapid temporal variations of TEC during solar flare events. Taking advantage of the availability of fast computing machines, as well as the advancement of machine learning techniques and Big Data algorithms, Adolfs and Hoque developed a more sophisticated TEC model featuring the NWA and other effects. Investigation shows that the NN model can successfully reproduce the evolution of the NWA effect during low solar activity conditions. However, predicting TEC during geomagnetic storms is still a challenging task for ionospheric models. A NN-based model is developed which predicts relative TEC with respect to the preceding 27-day median TEC, during storm time over the European region. The correct representation of global-scale electron density is crucial for monitoring and exploring the space weather. Considering this, several tomographic reconstruction techniques have been developed using ground-based GNSS data as well as space-based GNSS data. In comparison to previous techniques, advances are made in spatial and temporal resolution, and in the assessment of results. Also, the results show that the tomographic technique is capable of reproducing plasma variabilities during geomagnetically disturbed periods including features such as equatorial ionization anomaly enhancements and depletion.

Projektbezogene Publikationen (Auswahl)

 
 

Zusatzinformationen

© 2025 DFG Kontakt / Impressum / Datenschutz

Textvergrößerung und Kontrastanpassung