A5015613468- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- GNSS positioning and interference
- Astrophysics and Star Formation Studies
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Atmospheric Ozone and Climate
- Planetary Science and Exploration
- Radioactivity and Radon Measurements
- Nuclear Physics and Applications
- Space Exploration and Technology
- Geomagnetism and Paleomagnetism Studies
- Radiation Detection and Scintillator Technologies
- Astronomical Observations and Instrumentation
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2022-2025
University of Cologne
2016
The sensitivity of Global Navigation Satellite System (GNSS) receivers to ionospheric disturbances and their constant growth are nowadays resulting in an increased concern GNSS users about the impacts at mid-latitudes. geomagnetic storm June 2015 is example a rare phenomenon spill-over equatorial plasma bubbles well north from habitual. We study occurrence small- medium-scale irregularities North Atlantic Eastern Mediterranean mid- low-latitudinal zone by analysing amplitude scintillation...
Abstract Ionospheric indices give information about ionospheric perturbations, which may cause absorption, diffraction, refraction, and scattering of radio signals, including those from global navigation satellite systems (GNSS). Therefore, there be a relationship between index values GNSS positioning results. A thorough understanding their to results can help monitor forecast the reliability accuracy support precision safety life applications. In this study, we present three indices:...
Models of magnetically-driven accretion and outflows reproduce many observational properties T Tauri stars. This concept is not well established for the more massive Herbig Ae/Be We intend to examine magnetospheric in stars search rotational modulation using spectroscopic signatures, this first paper concentrating on well-studied Ae star HD101412. used near-infrared observations magnetic HD101412 test character its disk/star interaction. reduced analyzed 30 spectra HD101412, acquired with...
Since its launch in 2013, ESA’s Swarm satellite constellation has pushed the frontiers of space weather research and monitoring by means broad spectrum high-quality experiments on-board. Particularly, observations are being used to globally characterize small- mid-scale perturbations topside ionosphere that may cause severe amplitude phase scintillations trans-ionospheric radio signals. Ionospheric scintillation can signal outage, as well disruption modern technological systems for...
Abstract To aid single-frequency GNSS users, the Neustrelitz Total Electron Content Model (NTCM) has been proposed as an adequate solution to mitigate propagation errors besides GPS Klobuchar and Galileo NeQuick models. Using three effective ionization coefficients broadcast in navigation message driver parameters, version NTCM-GlAzpar, general, performs equal or better than NeQuickG when compared total electron content domain. In this work, we performed a global statistical validation of...
Multiple studies of scintillation phenomena have shown that, in certain situations, the intense phase fluctuations trans-ionospheric radio signals are associated with scattering on strong electron density gradients. The present study provides a theoretical framework for modeling such type fluctuation events. Using geometrical-optics approximation and retaining second-order smallness correction expansion eikonal function, we relate transmitted wave not only to total content (TEC) ionosphere...
The sensitivity of Global Navigation Satellite Systems (GNSS) receivers to ionospheric disturbances and their constant growth are nowadays resulting in an increased concern GNSS-users about the impacts at mid-latitudes. geomagnetic storm June 2015 is example a rare phenomenon spill-over equatorial plasma bubbles well North from habitual. We study occurrence small- medium-scale irregularities Atlantic Eastern-Mediterranean mid- low-latitudinal zone by analysing behaviour amplitude...
The Swarm data products are well-suited to address a number of crucial topics for space weather science and monitoring, such as investigating spatial temporal characteristics ionospheric irregularities or improving topside approaches in models monitoring forecasting the dynamics geo-plasma environment. Precision safety life applications using trans-ionospheric signals require key information on conditions particular perturbation degree ionosphere. Such particularly vulnerable against severe...
We present the results of a study temporal behaviour several diagnostic lines formed in region accretion-disk/star interaction three magnetic Herbig Ae stars HD101412, HD104237, and HD190073. More than 100 spectra acquired with ISAAC, X-shooter, CRIRES spectrographs installed at VLT-8m telescope (ESO, Chile), as well other observatories (OHP, Crimean AO) were analyzed. The spectroscopic data obtained He I lambda10830, Pa gamma lambda5876 lines. found that all program can be widely explained...
Context. Models of magnetically-driven accretion and outflows reproduce many observational properties T Tauri stars. This concept is not well established for the more massive Herbig Ae/Be Aims. We intend to examine magnetospheric in stars search rotational modulation using spectroscopic signatures, this first paper concentrating on well-studied Ae star HD 101412. Methods. used near-infrared observations magnetic 101412 test character its disk/star interaction. reduced analyzed 30 spectra...
The total electron content (TEC) measured along different satellite-receiver links is strongly sensitive to severe spatial gradients and rapid changes in the ionosphere. Therefore, key information on space weather conditions and, particular, perturbation degree of ionosphere crucial assure stable reliable services using Global Navigation Satellite Systems (GNSS) signals. By dual-frequency GNSS measurements, German Aerospace Center has developed Gradient Ionospheric indeX (GIX) Sudden...
Ionospheric disturbances can negatively impact the accuracy, continuity, availability, and integrity of Global Navigation Satellite Systems (GNSS) based services. Therefore, reliable description characterization these are essential to guarantee an adequate level safety for GNSS-based systems, susceptible strong spatial gradients rapid changes in electron density along receiver-satellite path (slant total content, STEC).This study aims compare various indices that describe current condition...
Models of magnetically driven accretion and outflows reproduce many observational properties T Tauri stars. For the more massive Herbig Ae/Be stars, corresponding picture is not well established. Nonetheless, it expected that flows in pre-main-sequence stars are guided from circumstellar disk to stellar regions high latitude along magnetic field lines inside a magnetosphere. Using near-infrared multi-epoch spectroscopic data obtained with ISAAC, CRIRES, X-shooter on VLT, we examined...
<p>GNSS single-frequency applications are affected by the interaction of radio signals with free electrons ionosphere, introducing range errors up to 100 m in L-band. Besides GPS Klobuchar and Galileo NeQuick ionospheric models, also Neustrelitz Total Electron Content Model (NTCM) has been proposed as a practicable solution mitigate such propagation errors.</p><p>In this investigation we present global statistical validation NTCM version driven...