Erik Schmölter

Space weather phenomena, which impact navigation and communication systems of our modern technological infrastructure, can influence flight operations affecting safety or efficiency of aviation. This study investigates these impacts with a comprehensive survey of industry professionals including 13 pilots. The results indicate that a significant amount of participants is familiar with space weather, but that specific impacts and potential risks are less understood. The results also show that communication between aviation stakeholders and space weather service providers in particular is perceived as lacking. This in turn has a negative impact on other issues, such as finding and using appropriate space weather services already in operation. The implications are discussed, highlighting a need for better communication between space weather service providers and aviation stakeholders, better space weather risk awareness, more in-depth space weather training and protocols as well as application-oriented space weather services. Thus, actionable instructions are provided to strengthen aviation’s resilience to space weather events and to ensure dependable systems.

The Mother's day storm from 10–13 May 2024 is one of the most extreme space weather events recorded in recent decades and triggered a strong ionospheric response with various impacts on communication and navigation systems. In this study the impact on the aviation sector, and more specifically air traffic management, is investigated with Automatic Dependent Surveillance‐Broadcast (ADS‐B) data from the OpenSky network. For that purpose, the event is presented with solar radiation and wind observations to describe the space weather conditions. Further, the spatial and temporal variations of the ionospheric response over Europe are analyzed with total electron content (TEC) maps and the performance of positioning via Global Navigation Satellite Systems (GNSS) is examined with 100 reference stations. These analyses show well‐known space weather impacts including TEC perturbations, sudden ionospheric disturbances, signal‐loss and degraded GNSS performance. Consequently, these effects are also expected for the GNSS positions transmitted via ADS‐B, and the analysis confirms that a higher frequency of such anomalies occurs along flight tracks during the event (increase of up to 2.55%). These anomalies may manifest as data gaps or as position errors of various types, which in turn could decrease the visibility and awareness of participants in shared air spaces. The correlation between space weather and anomalies in ADS‐B, as also shown in preceding studies, is thus further substantiated and motivates for follow‐up research that combines application‐specific data like ADS‐B with commonly used ionospheric observations.

Total electron content (TEC) maps are essential for understanding the temporal and spatial variability of the ionosphere, which is of particular importance during the current solar cycle with its multitude of extreme space weather events. This study presents an improved method for the global TEC map of the Ionosphere Monitoring and Prediction Center (IMPC) by incorporating an algorithm based on radial basis function interpolation. By refining the generation of the global TEC map, the accuracy and granularity of ionospheric gradients, which occur during these events, are significantly improved. The validation through comprehensive comparisons with the established TEC map and the global TEC map of the Technical University of Catalonia (UPC) confirms that the new algorithm outperforms previous results. Thus, a more robust framework for ionospheric research and application is provided. TEC gradients derived from the improved TEC maps are important for understanding the space weather impact on Global Navigation Satellite System (GNSS) applications. The new results can support these with more reliable and consistent predictions by accurately capturing these gradients.

Previous research has indicated that geomagnetic activity plays an important role in influencing the ionospheric delayed response to solar activity variations at the solar rotation time scale depending on solar activity conditions. In this study, we employed the Thermosphere‐Ionosphere‐Electrodynamic General Circulation Model to investigate the vertically resolved impact of geomagnetic activity on the ionospheric delay over the solar rotation period from 29 April to 25 May 2015. This time period was chosen due to its representative moderate solar and geomagnetic activity conditions. Our analysis revealed that the ionospheric delay increases with altitude due to geomagnetic activity and is more pronounced in the Southern Hemisphere than in the Northern Hemisphere. To further understand the underlying mechanisms responsible for the observed changes in ionospheric delay, we examined neutral species ( and ), their ratio , and neutral temperature. The results show that thermosphere‐ionosphere composition varies both vertically and horizontally in response to geomagnetic activity, and that these composition changes contribute to vertical variations in ionospheric delay.

The role of geomagnetic activity in the delayed response of the ionosphere along with the solar influences was investigated through a series of controlled simulations of the National Center for Atmospheric Research Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model under conditions of moderate geomagnetic storms during varying solar activity. In addition, observed ionospheric total electron content data sets were used to investigate the ionospheric delay and to compare it with the model simulations. The ionospheric delay varies spatially and seasonally depending on the solar and geomagnetic activity conditions. The simulations show a global decrease in ionospheric delay during Northern Hemisphere spring, except at high‐latitudes in the Northern Hemisphere under moderate geomagnetic activity. The delay increases in the Western Hemisphere during the winter season. We found that the ionospheric delay during the 27‐day solar rotation period changes based on whether geomagnetic activity occurs before or after the peak solar rotation day. This study emphasizes the significance of considering the geomagnetic activity when calculating ionospheric delay.

Space weather events can disrupt satellite navigation, potentially compromising also the accuracy of real‐time flight tracking via Automatic Dependent Surveillance‐Broadcast (ADS‐B). This in turn could limit the situational awareness of pilots and reduce the efficiency of the air traffic management. This study shows these impacts of space weather for selected flight tracks during the 9 February 2024 solar flare and compares the ADS‐B reported data with solar flux and total electron content measurements. Gaps and position errors in ADS‐B reported data, which reduce the visibility of the aircraft to other participants in the airspace, correlate well with the flare peaks and corresponding ionospheric disturbances showing a clear impact. These first results are further used to discuss appropriate space weather products for the pilot briefing as well as in‐flight monitoring, since existing approaches can be extended with the ADS‐B information to provide more precise space weather predictions.

A comprehensive understanding of ionospheric irregularities is crucial for satellite communications and navigation systems. These irregularities are significantly shaped by various external factors, including solar activity, geomagnetic disturbances, and impacts from the lower atmosphere. This study aims to underscore the complex irregularities within the thermosphere-ionosphere system while elucidating the substantial role of solar and geomagnetic drivers, as evidenced by observational data and model simulations. We will analyze key parameters of the thermosphere and ionosphere, including the ratio of atomic oxygen (O) to molecular nitrogen (N2), molecular oxygen (O2), total electron content (TEC), and electron density (Ne). For this analysis, we will utilize data from the Global-Scale Observations of the Limb and Disk (GOLD) ultraviolet imaging spectrograph, the International GNSS Service (IGS), and predictions from the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). Furthermore, we investigate the delayed response of TEC to changes in solar flux over a 27-day solar rotation period, taking into account the effects of geomagnetic activity. Our findings reveal that geomagnetic activity plays an important role in influencing the ionospheric delay.

Having a comprehensive understanding of the ionosphere's irregular behavior and its response to solar activity is crucial for satellite communication and navigation applications. The sun's extreme ultraviolet (EUV) and ultraviolet (UV) radiation are the primary sources of energy for the Earth's thermosphere and ionosphere (TI). To understand the global response of TI parameters (e.g., O/N2, and the peak electron density (Nmax)) to changes in solar irradiance, various data have been used. These include the Global-Scale Observations of the Limb and Disk (GOLD) ultraviolet imaging spectrograph, solar radio flux F10.7, predictions from the Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) model, and International Global Navigation Satellite System Service total electron content maps (TEC). The comparison between these measurements shows that the CTIPe model successfully reproduces the behavior of the low- and mid-latitude ionosphere during both low and high solar activity.The study also investigated the delayed ionospheric TEC response against solar flux variations within the 27-day solar modulation. It was observed that the delay is less than one day, which was also confirmed in model simulations. Furthermore, the model simulations showed that the ionospheric time delay is significantly affected by various physical processes such as diffusion, photodissociation, solar and geomagnetic activities, and wave dynamics.

The solar extreme ultraviolet (EUV) radiation drives the major ionization processes in the upper atmosphere. Its variability causes a related response in ionospheric observables. Especially of interest is the delayed response of electron density (Ne), integrated total electron content (TEC), and the density of major neutral and ionized species to the 27-d solar rotation period. But this solar signature is often influenced by underlying trends on shorter and longer time-scales. Therefore, this study examines the ionospheric response to a solar 27-d signature superposed with a long-term increase in solar EUV, showing that complex composition changes in the upper atmosphere influence the expected response significantly. Using high-resolution simulations of the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM), we compare two different 27-d solar rotation periods from the year 2014 with enhanced solar activity. This allows us to compare an almost ideal solar activity input with one that is superposed with an increase in solar activity. The main results show that the accumulation of ionized species O+ and O2+ in the lower ionosphere, especially up to the maximum density of ionized oxygen (O+) at about 230 km, is significantly affected by the long-term increase in solar activity. Nevertheless, the 27-d solar rotation period dominates the ionization in both, ideal and complex model run for altitudes above 230 km. Thus, our results are in good agreement with preceding studies and extend the study of the delayed ionospheric response to more complex cases.

Safe and efficient management of the constantly growing air traffic is an important task. For that reason, the international civil aviation organization (ICAO) approved Automatic Dependent Surveillance (ADS) system is used to share information (e.g. position, altitude and speed) between aircraft and air traffic control units. This improves the situational awareness and visibility of aircraft but also the environmental impact and air space capacity. Both applications of ADS, Broadcast (B) and Contract (C), rely on satellite-based communication and navigation services, which can be significantly disturbed by space weather impacts (e.g. loss of the signal and position errors). Therefore, related impacts are also observed for ADS records especially during extreme space weather events. We will present such impacts for both, ADS-B and ADS-C, with first results from an analysis covering periods with solar flares and geomagnetic storms. We will also discuss the challenge of differentiating space weather impacts from other influences. Finally, we will give an outlook how monitoring these impacts could contribute to space weather services.