TNA Project Overview

Postponed (due to technical reasons)

Abstract: A new technique for investigating dust charging in the PMSE (polar mesospheric summer echoes) source region is proposed and discussed in our recent work at EISCAT (European Incoherent Scatter Scientific Association) through collaboration with Dr. Kosch at the University of Lancaster (Mahmoudian et al., 2020). We employed the first high-frequency (HF) modulation of the PMSE with varying pump power during 2019 campaign at EISCAT. Two experiment setups including HF pump power stepping as well as quasi-continuous power sweeping were used. The experiment was designed based on a computational mode capable of simulation of PMSE evolution during HF pump modulation in order to develop a new approach for studying the dust charging process in the PMSE source region. The charge state of dust particles along with background dusty plasma parameters is estimated using the experimental and computational results. We have designed a detailed future experiment based on background dusty-plasma parameters. We propose to conduct this experiment that can be a breakthrough for investigating exact dust charge state in space for the first time. Mahmoudian, A., Kosch, M. J., Vierinen, J., & Rietveld, M. T. (2020). A new technique for investigating dust charging in the PMSE source region. Geophysical Research Letters, 47, e2020GL089639. https://doi.org/10.1029/2020GL089639

Abstract: Instituto de Astrofísica e Ciências do Espaço at the University of Coimbra (IA-UC) has a small group (and only one working permanently on this subject in Portugal) of researchers working in the area of ionospheric studies. To the moment no systematic studied of ionospheric response to space weather disturbances (i.e., disturbance of the solar and magnetospheric origin) were performed for Portuguese regions, neither Continental nor Insular (Azores and Madeira). One of the reasons is the lack of good quality data. Thus, the compilation of a database of ionospheric parameters including the total electron content (TEC) for the whole Portuguese region will be a necessary step for any study: data analysis, development of regional models to predict ionospheric response to different space weather events, development of regional ionospheric maps or other products that can be used by national service providers and end users.

Significant amount of the GNSS data from the Portuguese geodetic GNSS networks (as RAEGE-Az and RENEP) cannot be added to a such database because these data are available only as GNSS raw or pre-processed data formats (e.g., RINEX) and have to be converted to TEC data. Unfortunately, IA-UC team members did not have sufficient experience in such data processing. The PITHIA-TNA call was a perfect opportunity for the IA-UC team members to obtain new knowledge working in collaboration with the UPC-IonSAT team that has extensive experience in collecting and processing GNSS data from different GNSS systems.As a result of the collaboration with UPC-IonSAT team, the IA-UC team obtained necessary knowledge and software to process the files and significantly enlarged the Portuguese ionospheric parameters database using high quality data from the Azores Archipelago. The new data allowed to perform comparative studies of ionospheric disturbances observed during geomagnetic storms at different longitudinal sectors.Also, the UPC-IonSAT team agreed to support the IA-UC team in a planned development of RIMs for Portugal using data from RENEP and RAEGE-Az GNSS networks. The IA-UC will submit a project to a Portuguese national call for research projects in summer 2023 with UPC-IonSAT team members as advisors/consultants of the project.

Kasper van Dam, Eelco Doornbos

Abstract: This project aims at identifying longitudinal differences in traveling ionospheric disturbance (TID) characteristics for two midlatitude ionospheric stations located near Pruhonice, Czech Republic (50.0 N, 14.5 E) and Kharkiv, Ukraine (49.6 N, 36.3 E) and having very close latitudes. In most cases, daytime TIDs are associated with acoustic gravity waves (AGWs). Since most of the AGWs in the ionosphere originate from the lower atmosphere, this project mainly focuses on regional features of TID propagation due to the different meteorological or ground conditions immediately beneath the local ionosphere. Using the combination of the different techniques (ionosondes, incoherent scatter and Doppler radars), the following TID parameters will be determined or estimated: diurnal occurrence at each location; predominant period, vertical and horizontal phase velocity and wavelength, relative amplitude of electron density fluctuations. This project will enable enhancing our knowledge of regional behavior of TID characteristics and improving prediction capabilities of ionosphere models.

The auroral latitudes constitute a major location to progress in this new approach. Up to now, the previous results could be proved only in the E-region (around 110 km height), and only with the atomic oxygen green line. Thanks to this experiment campaign, we could prove that it also works at lower altitudes (85 km) and in the F region (220 km) by observing the purple nitrogen band and the red atomic oxygen line and comparing to the EISCAT data.

Abstract: Space Hurricane is a large-scale magnetic vortex structure spanning the polar ionosphere and magnetosphere, which was first discovered and dubbed by the research team from Shandong University, using optical observation onboard the Defense Meteorological Satellite Program F16 satellite. This project attempts to answer the question: Can ionospheric response to Space Hurricane events be observed from GNSS and Ionosonde data? Through the detrended Vertical Total Electron Content (VTEC) keogram derived from GNSS measurements and the key parameters from Ionosonde data, the answer is yes. The Observatori de l'Ebre (OE) node of PITHIA-NRF gives strong support on Ionosonde data processing and analysis, as well as valuable discussion.

Abstract: Understanding the complex dynamics in the upper atmosphere is very challenging. The study of the ionosphere irregularities during disturbed geomagnetic conditions can shed light on some of its characteristics. In last years, it was observed that several irregularities effects during geomagnetic storms were placed in southern Europe at 35º-40º geomagnetic latitudes. In this project, ionosphere effects of two moderate geomagnetic storms, 26–27 February 2014 and 17–18 September 2021, were studied over the Iberian Peninsula using different data sources. Data came from digital ionosondes in Spain, Italy and Greece; Global Navigation Satellite System (GNSS) derived Total Electron Content (TEC) and Rate Of TEC Index (ROTI) from several receiver stations in Spain, Portugal and Morocco; and UPC Quarter-of-an-hour time resolution Rapid GIM (UQRG), vertical TEC global ionosphere maps (GIMs) produced at 15 minutes intervals by the Universitat Politecnica de Catalunya (UPC, Spain). The main outcomes of this analysis showed that, during the two moderate storms, spread-F and high values of ROTI, indicating the presence of irregularities, were found in a very localized area (Southern Iberian Peninsula and northwest Africa) and local times (nighttime). Irregularities eastwards and northwards of that location were not found. Some possible explanations for these observations were proposed. The effects observed during the 26-27 February 2014 storm were related to the position of the Equatorial Ionosphere Anomaly (EIA). For the other one (17-18 September 2021 storm), they were attributed to the Perkins’ instabilities. Thanks to PITHIA-NRF project and the TNA program, skills to analyze ionograms with presence of irregularities such as spread-F were acquired, and it was provided access and training to use electronic Space Weather upper atmosphere (eSWua) web portal from Istituto Nazionale di Geofisica e Vulcanologia (INGV) to download the ionograms to detect the spread-F.

Abstract: The variable space weather conditions can harvest detrimental impacts on satellite communications, Global Navigation Satellite Systems (GNSS), and countless other applications. These negative impacts emphasize the necessity to better understand and predict the upper atmosphere effects in the near-Earth environment, specifically, the propagation delay, bending, and interferences of radio signals in the ionosphere. This project aims to address this scientific problem through a better understanding of space weather phenomena and analyses to characterize ionospheric plasma depletions. In this work, local features of the ionosphere are identified, monitored, and characterized from ionosonde measurements at Ebro Observatory, satellite ultraviolet images from Special Sensor Ultraviolet Spectrographic Imager (SSUSI), total electron content (TEC) index (ROTI) from GNSS, and all-sky 630 nm images at Oukaïmeden Observatory. Several conclusions, questions, and conclusions are discussed, especially the dynamics and coupling processes of these depletions in relation to upper atmosphere and space weather conditions during the geomagnetic storm of 28 February 2014.

Abstract: We have developed recently an imaging polarimeter called PLIP (Polar Lights Imaging Polarimeter) which is able to measure polarisation of the three main auroral emissions (green, red and blue) on a large FOV (~44° × 30°) on the sky. An observation campaign will be organized at the Skibotn Observatory in November 2022 on a 10 day period centred on the New Moon (23 November) to avoid strong contamination by Rayleigh-scattered moonlight. The goal is to search for a possible link between the AoLP of the auroral emission lines and the directions of field-aligned and/or ionospheric currents. To achieve this objective, we plan complementary blue line observations with the ALIS_4D optical network which will provide us a 2-D reconstruction of field-aligned electron fluxes. With this TNA proposal, we would like to obtain additional measurements with the UHF/VHF antenna of EISCAT in Tromso. The UHF antenna should be operated field-aligned to provide a reference point to validate the results obtained with inversion of ALIS_4D optical observations. The VHF antenna should be operated in tri-static mode in order to obtain an estimate of the direction of the ionospheric currents, which will then be compared to AoLP (Angle of Linear Polarisation) observations obtained with PLIP. If possible, we request also a secondary node to be able to use the VHF receiving mode of KAIRA from the SGO node.

Abstract: The ionosphere is the most important atmospheric layer that affects the radio signal between space-based missions and ground-based stations. All the disturbances that occur in the ionosphere (sudden changes in ion and electron densities) affect the signal as they can rapidly modify the amplitude and phase of the radio waves. Such modifications are called ionospheric scintillations. They represent a high-risk effect for the signal from GNSS (Global Navigation Satellite System) which is used for high-precision calculation of position and time synchronization. The ASPIS (Autonomous Service for Prediction of Ionospheric Scintillations) activity is dedicated to wider study if it is feasible to develop a data-driven service that will use available solar, space weather, geomagnetic, ionospheric, thermospheric data for a particular location as an input and autonomously provide an assessment of ionospheric scintillation in a specific time ahead as an output. Thanks to the PITHIA-NRF TNA program and during the stay at DLR-SO Node in Neustrelitz (DE), important progress in this activity was obtained. In what follows, the project process and outcomes are discussed and the follow-up activities are proposed.

Abstract: The project describes the analysis of sensitivity of electron density (ED) measurements collected by Swarm satellites, and selected ionospheric parameters determined by Athens ionosonde to the seismicity in the Aegean region. The period selected for the analyses extends for two years: 2020-2021. The magnitudes of the earthquakes (EQs) in 2020-2021 reached 7.0, and this was the strongest seismic activity in this region in time of Swarm mission. Swarm ED and ionosonde time series are analyzed with the use of short-term Fourier transform (STFT) in order to selectively chose those signal parts, which are the most sensitive to external, seismically-driven disturbances. The correlation between the seismically-driven ionospheric disturbances detected by Swarm and the EQs in the Aegean region revealed as higher than the correlation of Swarm with geomagnetic index and solar radio flux. The selected signal parts of ionosonde-derived parameters are also much more correlated with the seismic activity than with F10.7 or Kp index. NOA has provided ionosonde data, and hosted the investigators in Athens for extensive discussion on the project.

Abstract: Until recently, it was widely accepted that scintillation events do not pose any significant danger to GNSS-based technologies at middle latitudes. However, the sensitivity of GNSS instruments and their abundance constantly grow resulting in a concern of GNSS-users about impacts of ionospheric scintillations on the quality of the GNSS signal in the middle latitudes. Some studies were performed to assess the recurrence and the amplitude of ionospheric irregularities at middle latitudes (Mrak et al., 2020, https://doi.org/10.1029/2020RS007131), still, no such studies were ever performed for Portugal. The occurrence of potential ionospheric scintillation affecting low elevation southward GNSS measurements from receivers in Southern Europe can be studied using the S4 and ROTI scintillation indices computed from permanent GNSS receivers located in Southern Europe, during geomagnetically quiet and active periods.

Unfortunately, there are not many data sets of scintillation indices (SI), such as S4 and ROTI, that cover the SW part of the Europe (Iberian Peninsula). The IA-UC team already has access to a significant amount of GNSS SI observations made between November 2014 and February 2019 at Lisbon airport in the frame of one of our previous projects SWAIR (ESA Small Artes, 2014-2022, see Barlyaeva et al., 2020). This data set generated by a GNSS receiver with the SCINDA software consists of the total electron content (TEC) and SI data, available both in the SCINDA and ASCII format (Morozova et al., 2022b). The TEC data were already analysed, verified, and used for several studies (Morozova et al., 2020, 2022a), but the SI data still need to be verified.

Preliminary tests of the SCINDA SI (S4 and ROTI) series (Oliveira and Morozova, 2022) suggest that there are no significant flaws in the observational series, however the full data set still needs a detailed verification.

We contacted the INGV scintillation group that runs the eSWua database which includes scintillation data as well. We would like to validate our scintillation data and put them in the context of supporting the European capabilities of scintillation monitoring by providing access to this data set through eSWua. An open access to this data will be beneficial for the ionospheric community: the ionospheric scintillations in the SW part of the Europe are poorly studied because of the limited amount of the observational data.

We expect that work done during both the PITHIA-TNA project we propose and further collaboration projects with the INGV group will help to fill this knowledge gap and will be beneficial both for the Portuguese and Italian ionosphere communities and would increase the monitoring capabilities in the Mediterranean area.

Abstract: HAVES has three main objectives, nighttime spread F characterization over Roquetes, comparison of two large scale Traveling Ionospheric Disturbances (LSTIDs) detection methods and a long-term study of intermediate descending layers (IDLs). The first objective, the characterization of nighttime spread F, was based on an extended ionogram dataset recorded by the DPS-4D Digisonde during the interval 2012–2022 over Roquetes, Spain (40.8°N; 0.5°E). These ionograms were analyzed to identify nighttime spread F events and evaluate any seasonal and solar activity trends. Clear seasonal characteristics and yearly inverse solar activity spread F dependence was identified. Travelling ionospheric disturbances (TIDs) (excited by gravity waves) are neutral atmospheric waves that propagate horizontally and vertically to interact with the ionospheric plasma, through some mechanism, causing wave-like plasma structuring at a wide range of velocities, wavelengths and periods playing an important role in the exchange of momentum and energy between different latitudinal and altitudinal regions of the upper atmosphere (Hunsucker, 1982). LSTIDs are characterised by Periods: 30min‒3hr; Wavelengths≥1000km) (Hunsucker, 1982). LSTID activity over Roquetes has been studied in terms of the HF-INT and HTI techniques (exploiting ionograms at a 5-min resolution recorded from 2016 to 2022). Similarities and differences in the diurnal LSTID occurrene were noted over Roquetes as extracted by these two different techniques. The third aspect of HAVES was a long-term study of intermediate descending layers (IDLs) over Roquetes by applying the HTI methodology. 

TNA3

NOA

Rukundo Wellen

Characterization of ionospheric irregularities in the midlatitude region; Case study: unusual plasma density depletion and enhancement at around noontime

Finished

Affiliation: Egypt Japan University of Science and Technology

TNA3

INGV

Jorge Habib Namour

Total Electron Content global and regional forecasting maps using artificial intelligence techniques

Finished

Affiliation: Laboratorio de Computación Científica (LabCC) - Facultad de Ciencias Exactas y Tecnología (FACET) - Universidad Nacional de Tucumán (UNT), Tucumán, Argentina

Abstract: This research plan is proposed in the frame of long-existing collaborations between INGV and Universidad Nacional de Tucumán to study, monitor and analyse the variability and morphology of the ionosphere by means of space and ground-based instruments. Moreover, under the mentioned collaboration, in Argentina, there are 2 AIS-INGV ionosondes and 2 GNSS receivers installed and operative that provide real-time data for ionosphere monitoring and space weather applications. The understanding of the ionosphere plays a central role in space weather (SWx) operations. Extreme SWx events can disturb the ionospheric conditions and in consequence, unwanted effects can be observed in space-based technologies. During geomagnetic storms, HF radio propagation may be severely affected and in consequence, telecommunications; satellite navigation may be degraded for days; geomagnetically induced currents may damage extended energy pipelines; etc.

GNSS (Global Navigation Satellite System) systems signals are especially affected by Space Weather. GNSS signals are trans-ionospheric communications and in consequence, they are subject to instabilities present within the ionospheric plasma. GNSS-derived parameters such as Total Electron Content (TEC) or ionospheric scintillation parameters (e.g. S4 index) can be used to understand and forecast the ionospheric conditions. This is particularly true at high and low latitudes where the ionosphere is highly dynamic and responsive to the changes in the geomagnetic field induced by the SWx events.

In particular, modern analysis techniques such as machine learning (ML) have been proven to be suitable to forecast different ionospheric events at different scales using data provided by GNSS receivers and ionosonde, among other instruments. These ML models are based on heuristics over a big volume of data and have been obtaining great results in many fields including Swx.

TNA3

LOFAR

Kacper Kotulak

Use of LOFAR data for ionospheric studies

Finished

Affiliation: Space Radio-Diagnostics Research Centre

Abstract: The fluctuations of phase and intensity received by the LOFAR radiotelescope are caused by the ionoshpere irregulaties, that phenomena is radio-wave scintillation. The combination of the different measuring techniques, such as all-sky and beamformed observations of selected sources, could advance the understanding of the ionosphere mechanisms. That knowledge can be then utalised to forcast the space weather and improve the observational capabilities of LOFAR radiotelescope, including the dynamic scheduling of the observation programs.

TNA4

IAP

Tamás Bozóki

Upward Propagating Gravity Waves in the lower and middle ionosphere (UPGW)

Finished

TNA5

 NOA

Sivakandan Mani

Climatology of Medium Scale Traveling Ionospheric Disturbances anddevelopment of probabilistic forecasting model

 Finished

TNA5

OE

Attila Buzás

SOlar Flare-induced Absorption in the ionosphere Research– SOFAR

Finished

TNA5

INGV

Ola Ahmed Mustafa Abu Elezz

Validating the Swarm S4 index over Africa using Eswua database

Finished

TNA5

CBK-PAS

Oyuki Chang

Radio scintillation studies for prospects of space weather forecasting and analyses.

Finished

TNA5

EISCAT

Anna-Marie Bals

Estimating ionospheric irregularity layer height and drift velocity with GNSS and incoherent scatter radar

Finished

TNA6

UPC-IonSAT

Haixia Lyu

Assessment of ionospheric mapping function models using dSTEC measurements in latitudinal bands under different ionospheric conditions

Finished

Affiliation: GNSS Research Center, Wuhan University, China

Abstract: The ionospheric mapping function defines the conversion between Vertical Total Electron Content (VTEC) and Slant Total Electron Content (STEC). Even under quiet ionospheric conditions, the slant ionospheric delay estimation error caused by the typically adopted thin-layer mapping function can reach as high as several meters, severely affecting the availability and integrity of high-precision GNSS services. The increasing number of single- and multifrequency GNSS users, e.g., low-cost geodetic-grade receivers in applications like precise agriculture, and smart device users in mass markets, drives greater demands for high-precision location services. However, mitigating the ionospheric mapping function error remains a perennial challenge of GNSS positioning. To address this challenge, a new study group “Ionospheric Mapping Function” has been established in the frame of the IGS Ionosphere Working Group [Lyu et al. 2024]. Attempts to improve the ionospheric mapping function by considering the realistic vertical structure of the ionosphere, and meanwhile the horizontal gradient to a certain extent, have demonstrated the benefit of applying the tomographic solutions derived from GNSS measurements to the ionospheric mapping function [Hernández-Pajares et al. 2005, Lyu et al. 2018]. In the same line, a more direct way of estimating STEC using accurate tomographic solutions is proposed, which depends neither on VTEC models nor on the ionospheric mapping function. Initial validation results show smaller dSTEC RMSE by the direct STEC estimation with interpolated electron densities from tomographic solutions, compared to the traditional way, i.e. UQRG VTEC with the single-layer ionospheric mapping function.

TNA6

OE

Kitti Alexandra Berenyi

Validation AND Assessment of near-real time detection and forecasting of LS-TIDs in Europe (VANDALS-TIDE)

Finished

Affiliation: HUN-REN-ELTE Space Research Group, Budapest, Hungary Doctoral School of Environmental Sciences, ELTE Eötvös Loránd University, Budapest, Hungary | HUN-REN Institute of Earth Physics and Space Science, Sopron, Hungary

Abstract: The main scientific purpose of the VANDALS-TIDE TNA project was to study specific ionospheric phenomena called Large Scale Travelling Ionospheric Disturbances (LSTID) events, to validate and assess the methods of the detection and forecasting them and define the potential early indicators of LSTID activity. LSTID detection and forecasting products were cross-validated with analysis of independent data providing clear TIDs signatures. The other aim of the current VANDALS-TIDE TNA project was to get to know better the different methods used for LSTID detection and forecast at the PITHIA-TNA nodes. As part of the validation process, the forecasted events needed to be compared with measured data from the High Frequency Interferometry (HF-INT) method, detrended Total Electron Content (dTEC), detrended isodensity contours (dNe(h)), and D2D products (from Digisonde measurements) over Europe.

TNA6

OE

Sivakanda Mani

Comparisons and validation of the TIDs occurrence in the ionospheric tilt measurements with the GNSS observation (CVTIDs)

Finished

Affiliation: Leibniz Institute of Atmospheric Physics (IAP) at the University of Rostock, Germany

Abstract: Medium-scale traveling ionospheric disturbances (MSTIDs) are wave-like disruptions in the ionospheric plasma density, with horizontal scales ranging from 100 to 500 kilometres. These disturbances are caused by various sources, including gravity waves, solar terminators, and electrodynamic instability processes. MSTIDs can be observed both during the day and at night; however, the mechanisms behind daytime and nighttime MSTIDs differ. Research indicates that daytime MSTIDs are primarily generated by primary and secondary gravity waves that originate in the lower and middle atmosphere, respectively. In contrast, nighttime MSTIDs are attributed to electrodynamic processes, specifically Perkins instability, which is associated with coupling between the E- and F-regions of the ionosphere. Despite their significance, the climatology of MSTIDs over the European sector has not been thoroughly explored. Various methods and datasets have been employed to study the occurrence of MSTIDs. In this analysis, we compare the occurrence of traveling ionospheric disturbances estimated from ionosonde tilt measurements with those derived from differential total electron content (dTEC) and ionogram feature-based methods. We found a generally good correlation among these three approaches, with some exceptions.

TNA6

SGO

Claudia Martinez-Calderon

Study of natural VLF emissions: propagation and characteristics from multi-point observations (VLF-CHAMP)

Finished

Affiliation: Institute for Space-Earth Environmental Research, Nagoya University, Japan

Abstract: The interaction between the Earth’s magnetic field and the solar wind creates the magnetosphere, a region of space where particles are trapped in what we call the radiation belts. These energetic particles can be harmful to humans and their activity in space. Satellites that spend most of their lifetime in these regions are particularly susceptible, since sudden changes of plasma conditions can result in catastrophic failures. Very Low Frequency (VLF, f=3–30 kHz) electromagnetic waves naturally occur in the magnetosphere, and can interact with certain electron populations. This results in electron acceleration to higher energies (energization) or loss into the atmosphere (particle precipitation resulting in aurora). VLF waves play a crucial role in regulating the dynamics in the radiation belts, meaning that understanding their spatial distribution and temporal variations is fundamental for space weather prediction. Understanding how these waves are generated and propagated, gives crucial information on wave-particle interactions that in turn are closely related to radiation belt dynamics.

The project uses data from the Kannuslehto (KAN) VLF receiver in Northern Finland combined with the Oulujarvi (OUJ) PWING station 360 km southwards to investigate the latitudinal propagation of VLF waves (particularly high-frequency emissions called bursty-patches). We focus on data analysis from both stations and the selection of specific events. These events will be used for ray tracing simulation (following the path of the waves) and triangulation of the ionospheric exit point (location where the waves exit the ionized upper atmosphere). This will give us a greater understanding on how the waves propagate in the magnetosphere, go across the ionosphere and finally manage to reach the receivers (KAN, OUJ). This study is complemented by the installation of an additional Japanese VLF receiver ~150 km north of KAN, near Angeli in Lapland.

TNA6

SGO

Kolos Nemeth 

Ionospheric influence on the propagation of ELF radio waves (PROPER)

Finished

Affiliation: Eötvös Loránd University, Hungary

Abstract: The scope of this project was to create a dataset of lightning-generated ELF-transients (Extremely Low Frequency) using the induction coil measurements from the Finnish Pulsation Magnetometer chain, operated by the Sodankylä Geophysical Observatory (SGO). The dataset includes measurements with two different sampling rates (40 Hz and 250 Hz) over a long period of time, allowing for validation as well as optimization of the method used for the ELF-transient identification. During the access, ELF-transients were successfully identified on the 250 Hz measurements from 2020 to 2021, with reliable results proved by comparison to the Hornsund station’s data. The identification method for the 40 Hz data required further refinement, achieving a success rate of 75.79% after adjustments. The developed identification algorithm was implemented on SGO’s computers, creating a great foundation for long-term continuous detection of ELF-transients in future data as well as extending back to 2013. This project contributes to a global database of lightning-related activity through the monitoring of ELF-transients. The findings support the continued development of detection methods for ELF-transients and lay the foundation for a long-term collaboration aimed at enhancing the quality and scope of this dataset.

TNA6

NOA

Wojciech Jarmołowski 

Spectral analysis of local ground-based GNSS-derived TEC time series in view of its’ Sensitivity to Earthquakes in Aegean region (TECSEA)

Finished

Affiliation: University of Warmia and Mazury in Olsztyn, Poland

Abstract: The time series of total electron content (TEC) calculated from dual-frequency electromagnetic phase observations at ground-based GNSS stations provide wide frequency band of TEC signal, which can be spectrally analyzed in time-frequency domain. The variation of TEC at different frequencies related here with the time of TEC collection can be triggered by different drivers from below and from above, and also by different channels of lithospheric-atmospheric-ionospheric coupling (LAIC). This study provides the first time frequency spectral analysis of station-based vertical TEC (VTEC) at two frequency bands, which constitutes a basis for the correlation analyzes of ionospheric VTEC disturbances with seismic, solar and geomagnetic activity. Aside from the seasonal variations, the diurnal and semi-diurnal VTEC variations are very strong and dominate in the analyzed signal. Therefore, the signals from time series at these wave periods are skipped in the analysis, which is useful in the analysis of intra-diurnal (several-hour) and inter-diurnal (several-day) effects separately. The PTHIA node at NOA provides RINEX data from local NOA GNSS stations, which together with publicly available IGS station data used as a reference, and also with ancillary geophysical parameters, are processed by spectral analysis. The spectrograms produce a basis for the correlation analysis of VTEC with sum of seismic energy and the earthquake records from the region of Aegean tectonic plate boundaries, but also with geomagnetic/solar activity. The proposed study involves data from almost entire year 2020, from local Aegean stations and more distant stations applied as a reference. The performed spectral analyses of VTEC, solar and geomagnetic parameters reveal new insights into different temporal scales of VTEC variations, and their correlation with geomagnetic index, solar wind and seismicity. The work gives a wide view on the complexity of VTEC signals, finds preliminary correlations and significantly facilitates planning future tasks of this research.

TNA6

OE

Iurii Cherniak 

High Rate Ionosonde Sounding Measurements And COSMIC-2 Radio Occultation Collocation Analysis (HRISMA-CROCA)

Finished

Affiliation: COSMIC Program Office, University Corporation for Atmospheric Research, USA

Abstract: There are challenges of practical interest in the study of the Earth’s ionosphere that require a detailed knowledge of the ionospheric plasma density distribution in space and time. The ionospheric F region around the peak electron density height of about 250–450 km causes the most significant impact on sub- and trans-ionospheric radio wave propagations, satellite communication, and global navigation systems. The vertical soundings of ionosphere by ionosondes and GNSS radio occultation (RO) retrieving are the most important techniques for the remote sensing of the ionosphere. Within the framework of this project, we plan to analyse together high sampling rate observations from Ebro ionosonde station with collocated COSMIC-2 RO measurements. Ionosondes provide the “benchmark” unbiased measurement of electron density in the ionosphere, while GNSS RO gives precise information on the altitudinal shape of EDPs and information about plasma distribution above the F2 layer peak. Having precise in time collocations between Ebro ionosonde and COSMIC-2 RO EDPs will allow us to improve our knowledge on how correctly combine these two different techniques of the ionosphere probing, obtain set of the reference EDPs that cover altitudinal range 100-500 km with the high accuracy which is necessary for the ionospheric models validation and improvement as well as detect and analyse similarities and differences in performances of ionospheric plasma irregularities detection over the Mediterranean region.

TNA6

SGO

Ivana Kolmasova

High latitude lightning atmospherics belonging to transient luminous phenomena (HILALI-TLE)

Finished

Affiliation: Institute of Atmospheric Physics of the Czech Academy of Sciences, Czechia

Abstract: Parameters of lightning discharges that generate Transient Luminous Events (TLE) are reflected in the properties of atmospherics—very low frequency (VLF) electromagnetic signals that propagate over long distances within the waveguide formed by the Earth's surface and the bottom of the ionosphere. During the PITHIA project, VLF waveforms recorded at the SGO station in Kannuslehto were analysed. These waveforms correspond to energetic winter lightning strokes over the Adriatic region that produced numerous elves. Additionally, I examined waveforms associated with Narrow Bipolar Events (NBEs) identified by the ENTLN lightning location network. NBEs are believed to generate blue jets. SGO provided the raw VLF data on which this analysis was based.

TNA6

SGO

Ondrej Santolik

Spectral properties of high latitude lightning atmospherics (HILALI-SPC)

Finished

Affiliation: Institute of Atmospheric Physics of the Czech Academy of Sciences, Czechia

Abstract: Parameters of lightning discharges that generate Transient Luminous Events (TLE) are reflected in the properties of atmospherics—very low frequency (VLF) electromagnetic signals that propagate over long distances within the waveguide formed by the Earth's surface and the bottom of the ionosphere. In the frame of the PITHIA project, I inspected the VLF spectra calculated from the data measured at the SGO station Kannuslehto. The spectra correspond to energetic winter lightning strokes over the Adriatic region that produced numerous elves. Additionally, I examined spectrograms associated with Narrow Bipolar Events (NBEs) identified by the ENTLN lightning location network. NBEs are believed to generate blue jets. SGO provided the raw VLF data on which this analysis was based. 

TNA6

INGV

Simon Mackovjak

Development follow-up of autonomous service for prediction of ionospheric scintillations (Scintillations)

Finished

Affiliation: Department of Space Physics, Institute of Experimental Physics, Slovak Academy of Sciences, Slovakia

Abstract: Ionospheric scintillations are among the most challenging space weather phenomena. The combination of their nondeterministic occurrence and their significant effect on modern technology makes them important risks that need to be mitigated. For this purpose, we have developed a proof-of-concept of Autonomous Service for Prediction of Ionospheric Scintillations (ASPIS). It is a machine learning-based service that uses data from GNSS receivers as input and provides nowcasts and forecasts of phase scintillations as output. The critical next step is to increase the technology readiness level of the system. For that, a reliable provider of real-time scintillation data is needed. Thanks to the PITHIA-NRF TNA program and during the stay at the INGV Node in Rome (IT), important progress was made in this activity.

TNA6

LOFAR

Maria Rioja 

Rapid wide-field precise measurement of Ionospheric Screens over LOFAR (LEAP-LOFAR)

Finished

Affiliation: Observatorio Astronomico Nacional, Spai

Abstract: We applied the SKA direction dependent calibration tool leap-accelerate on LOFAR data, with the goals of a) identifying suitable data b) demonstrating that the SKA tool could work with LOFAR data, c) measuring the ionospheric atmospheric distortions in multiple directions simply, rapidly and robustly and quantified the requirements for success and d) comparing these results to those from the LOFAR direction dependent calibration.

TNA6

EISCAT

Ashik Paul 

Coordinated study of ionospheric irregularities from the low and high latitudes using EISCAT and University of Calcutta VHF Radar (CIIR)

Finished

Affiliation: Institute of Radio Physics and Electronics University of Calcutta, India

Abstract: Coordinated study of ionospheric irregularities from the low latitudes and polar regions using EISCAT and the University of Calcutta VHF Radar under varying geomagnetic conditions will be conducted within the framework of this proposal. The main objective of this proposal is to understand the ionospheric response to intense geomagnetic storms from these two widely varying latitude zones. Using other collocated ionospheric probing instruments like a dual-frequency GPS receiver operational at University of Calcutta, efforts have been made to assess the different ionospheric irregularity scale sizes involved in the process. Since the low latitude ionospheric irregularities are found to occur predominantly during the local post-sunset hours of the equinoctial months of high solar activity periods, hence the experiment is planned in the second half of September, during local post-sunset hours of 13:00-17:00 UT, which corresponds to 19:00-23:00 LT at Haringhata in the Indian longitudes and 15:0019:00 CET at Tromso, the site of the EISCAT UHF Radar. While the low latitude ionosphere experiences radio signal outages as a result of the deleterious effects of irregularities even under geomagnetic quiet conditions, the polar latitudes usually respond to intense Space Weather events. It is important to note that historically there have been intense geomagnetic storms in the month of September, notably in 1999, 2011 and 2017. The present experiments utilized the space environment conditions that existed following a G3 class geomagnetic storm which occurred during September 12-17, 2024. Collocated GPS observations from Kolkata have also been considered. Fluctuations in electron density were found around 16:30-17:00 UT associated with positive ion drift velocities on September 18, 2024 when using the EISCAT Tromso VHF radar with the radar transmitted beam nearly parallel to the geomagnetic field lines. On September 19, 2024, the radar was operated in the wide latitude scan mode which showed presence of the auroral oval. On the other hand, observations from the low-latitude VHF radar at University of Calcutta exhibited prominent irregularity signatures around 14:00-15:00 UT at altitudes of 300-400 m. collocated GPS observations at L-band exhibited significant amplitude scintillations on a number of satellite links on both September 18 and 19, 2024. The report presented herewith attempts to draw a comparative study of the ionospheric responses on the days following a intense geomagnetic storm from the low and polar latitudes. Further studies on satellite-based measurements around the EISCAT Tromso VHF radar site will help understand the ionospheric dynamics that existed following the adverse Space Weather conditions at high latitudes.

TNA6

ROB-GNSS

Haris Haralambous 

Evaluation of a low-cost receiver for ionospheric monitoring (ELRIOM)

Finished

Affiliation: Frederick University, Cyprus

Abstract: High-grade GNSS receivers are the basis for ionospheric monitoring for more than two decades. Researchers at Frederick University are in the process of installing a network of GNSS receivers for ionospheric monitoring and would like to explore a low-cost solution that would facilitate a dense network for such a purpose. The housing and operation firmware of the low-cost receiver were developed by Cloudwater Ltd (a start-up established in Cyprus in 2019) with Ublox chip Zed F9-P. In this TNA project, the low-cost GNSS receiver UBXZ was tested at the ROB-GNSS node by comparing its ionospheric outputs with geodetic receiver results. For that we installed UBXZ close to the reference station BRUX (Brussels, Belgium) for 73 days (February to April 2025) and compared the vertical Total Electron Content (vTEC) outputs of the two receivers for GPS, GLONASS and Galileo constellations using the ROBIONO software. Results show infinitesimal differences between the two receivers, for the three constellations (0.08±0.58 TECu for Galileo, 0.02±0.42 TECu for GPS and 0.02±0.73 TECu for GLONASS). Consequently, the low-cost receiver developed by Cloudwater Ltd constitutes a relevant option for dense networks dedicated to Space Weather applications. 

TNA6

SGO

Liliana Macotela 

Estimate upgrades for the Kannuslehto VLF receiver (SPAKLE)

Finished

Affiliation: Earth Observation Unit, Norwegian Research Centre, Norway

Abstract: The propagation of Very Low Frequency (VLF: 3–30 kHz) radio waves is one of the few techniques capable of probing both the lower boundary of the ionosphere, known as the Dregion, and the magnetosphere. Since the inception of the Kannuslehto VLF receiver, no hardware upgrades have been implemented, and many electrical components have become outdated. Additionally, there are no backup components available for the receiver system, leaving it vulnerable in case of antenna failure or the need for repairs. Observations indicate that even simple component replacements can significantly influence the measurements, potentially reducing the sensitivity of the VLF receiver and compromising its current capabilities. Preserving the Kannuslehto VLF receiver's ability to detect new and diverse reported structures is therefore essential. Furthermore, members of the SPARKLE initiative have agreed to submit a proposal aimed at fostering cooperation and mobility projects between Finnish and Latin American universities. The primary objective is to unite researchers from both regions to test a modular-based VLF receiver, enhancing the system's resilience and adaptability.

TNA7

DLR-SO

Ozuem Victor Edward 

Improving Ionospheric Modeling in Near-Equatorial Regions Using the IRI Model, Swarm Data, and Machine Learning (IRI-EIA)

Closed (Finished, but due to changes in the life situation the user could not provide an end report)

Affiliation: Centre for Space Research, Anchor University Lagos, Nigeria

Abstract: Fluctuating space weather conditions can profoundly impact satellite communications, Global Navigation Satellite Systems (GNSS), and various other technologies. These challenges underscore the importance of enhancing our knowledge and forecasting capabilities regarding the upper atmosphere, especially in terms of how radio signals in the ionosphere are delayed, bent, and affected by interference. Additionally, predicting ionospheric conditions in near-equatorial and equatorial anomaly regions presents significant challenges. In these areas, ionization patterns can be particularly complex and variable due to factors such as the strong influence of the Earth's magnetic field, the presence of the Equatorial Ionospheric Anomaly (EIA), and the interplay of different atmospheric and space weather phenomena. This complexity necessitates advanced models and predictions to accurately assess and manage the effects on satellite and communication systems. This research aims to enhance ionospheric modeling for the near-equatorial regions of Africa by integrating Swarm satellite data, ground-based GPS RINEX observations, and the IRI model with machine learning techniques. The goal is to refine the IRI model’s accuracy for this region and develop predictive models that leverage satellite and ground-based data.

TNA7

CBK-PAS

Sergii Panasenko 

Characteristics of CIR-driven Storm indUced traveling ioNospheric Disturbances over mid-latitude Europe from Ionosonde And LOFAR data (SUNDIAL)

Finished

Affiliation: Institute for Near-Earth Space Research, National Technical University "Kharkiv Polytechnic Institute", Ukraine

Abstract: Magnetic storms are known to effectively generate atmospheric waves, result in negative effects on the space-based assets and require further thorough investigations. The goal of the proposed project was to search a relationship between auroral activity enhancement, initiated by corotating interaction region / high speed stream (CIR / HSS)-driven events and characteristics of traveling ionospheric disturbances (TIDs) observed over mid-latitude Europe. We thoroughly analysed both large-scale and medium-scale TID activity during CIR/HSS-driven magnetic storm on March 30 – April 6, 2023. 

Thanks to the PITHIA-NRF project and the valuable support provided by the TNA program, we successfully combined the efforts of scientists from the Institute of Atmospheric Physics CAS (Czech Republic) and the Space Research Centre PAS (Poland) to jointly detect and characterize TIDs using ionosonde, GNSS, and LOFAR scintillation techniques. A unified methodology was applied and further improved for data analysis, incorporating cross-correlation, spectral analysis, and bandpass filtering to ensure consistency across the obtained results. 

We detected the several time intervals with TIDs propagated from the high latitudes towards the equator associated with an enhancement in auroral activity. Ionosonde and GNSS based results show the consistency in estimation of TID characteristics. The detected large scale TIDs have the dominant periods of 50 – 80 min, horizontal phase velocities of 400 – 600 m/s and horizontal wavelengths of 1300 – 3500 km. In addition, an analysis of the LOFAR scintillation data revealed the intensification of irregularities which is likely to be caused by medium and small scale TIDs. The southward propagated TIDs in the broad range were detected and characterized during the selected magnetic storm interval. Based on this case study, we spotted that the TIDs at mid-latitudes were usually observed several (1 – 4) hours after the enhancement in the auroral activity characterized by IMAGE IE indices. We continue to analyse other CIR / HSS driven events to establish the validity of such relationship.

TNA7

SGO

Shin-ichiro Oyama 

Investigation of Magnetospheric Particle forcing to CNA taken by SGO riometers (IMPACTS)

Finished

Affiliation: Institute for Space-Earth Environmental Research, Nagoya University, Japan

Abstract: During magnetic storms, high-energy electrons and protons precipitate intensively into the polar ionosphere from the magnetosphere, leading to anomalous ionization in the lower ionosphere. The Sodankylä Geophysical Observatory (SGO) has been monitoring the latitudinal and longitudinal distribution of cosmic noise absorption (CNA) at auroral latitudes for several decades by operating a chain of riometers in Finland. More recently, SGO has deployed spectral riometers, which facilitate simultaneous measurements of CNA at multiple radio-wave frequencies from 20 to 55 MHz. This study will conduct a statistical analysis focusing on the variations in CNA during different phases of geomagnetic storms (initial, main, and recovery phase) in relation to the solar cycle. By combining datasets from a spectral riometer in Kilpisjärvi and an imaging riometer at the Syowa Antarctic station, this study performed a statistical analysis of the CNA evolution over magnetic local time (MLT), relative to the storm onset, and conducted a correlation analysis between the two collocated riometers. Hemispheric asymmetry was observed in the CNA evolution, and a statistical factor to convert the spectral riometer CNA to the KAIRA CNA was derived. 

TNA7

DLR-SO

 George Tasios

Identification of sporadic E layers using ROTI (IDESER)

Finished

Affiliation: National Observatory of Athens, Greece

Abstract: In this project we investigate the possibility to identify the occurrence of sporadic E layers over Europe based on the Rate of change of the Total Electron Content Index (ROTI). Considering the ROTI is routinely estimated as an index of ionospheric irregularities, with the assumption that most of the ionization is concentrated at 400 km, the challenge in this project is to re-estimate the ROTI using a low altitude IPP (for example 100 - 120 km), to recalculate the rate of TEC index (ROTI) and trace the Es. The ROTI of the European region is compared with Es parameters for the same region. The Es characteristics are estimated from Digisonde ionograms and from model estimated values obtained from the Es model of the Ionospheric Group of NOA.

TNA7

LOFAR

Aramesh Seif 

Ionospheric Scintillation Response to the April 2023 Major Geomagnetic Storm: A European Perspective

Finished

Affiliation: Department of Physics, Shahid Beheshti University, Evin, Tehran, Iran

Abstract: The ionosphere plays a critical role in the propagation of Global Navigation Satellite System (GNSS) signals. However, ionospheric irregularities, such as scintillation and electron density fluctuations, can significantly impact the performance of GNSS applications. Scintillation in trans-ionospheric signals, such as those used by the Global Positioning System (GPS), is caused by electron-density irregularities in the ionosphere. As these signals pass through the irregularities, they experience rapid and unpredictable changes in signal strength, resulting in amplitude and phase fluctuations. These fluctuations can lead to degraded receiver performance in several ways, from accuracy issues, such as range errors, to the loss of signal tracking [Paula et al. 2003]. Thus, obtaining reliable information about key parameters that describe the ionosphere's perturbation level is crucial for ensuring the required safety standards. The occurrence and intensity of ionospheric scintillation depend on factors like location, time, and the Earth's magnetic field. Despite decades of study, research gaps persist, primarily due to the need for specialized high-rate GNSS receivers.

This study examines ionospheric scintillation, total electron content (TEC), and Rate of TEC Index (ROTI) variability during the 23 April 2023 geomagnetic storm over Europe. We use the LOFAR (Low-Frequency Array) dataset to calculate scintillation in the megahertz range and gain insights into small-scale ionospheric irregularities. ROTI, calculated and provided from real-time GNSS measurements of a global network of receivers by the Universitat Politècnica de Catalunya (UPC-IonST), is used to assess large-scale ionospheric disturbances by measuring rapid TEC fluctuations. Additionally, we analyze ROTI and VTEC datasets from DLR for 29 LOFAR stations and evaluate the Gradient Ionosphere Index (GIX) to estimate ionospheric perturbations.

By combining data from LOFAR, UPC, and DLR, we explore the relationship between scintillation indices and ROTI values, providing a comprehensive analysis of ionospheric irregularities during storm conditions. This research enhances our understanding of space weather impacts on GNSS systems and communication infrastructure across Europe. The findings will improve predictive capabilities for geomagnetic events and define strategies to mitigate the risks associated with ionospheric disturbances.

TNA7

DLR-SO

Georgios Stamatakis 

Explosive Events Ionospheric Disturbances (EEID)

Finished

Affiliation: National Observatory of Athens, Greece

Abstract: Even though the space weather is the main driver of ionospheric disturbances, phenomena originating in the lower atmosphere may cause regional ionospheric disturbances as well. This study will be investigating possible ionospheric disturbances related with Beirut explosion, during 2020/08/04 (Hassel et al., 2020). For the process and analysis, Digisonde and GNSS stations data will be used for an holistic research approach. Of course, this effort is challenging, since there are many factors affecting the ionosphere and the investigation tools are restricted as for their resolution and their efficiency as well.

In the specific study, we investigate possible effects of the Beirut explosion in the ionosphere over the European region, based on the analysis of the DLR ROTI (Rate Of TEC Index) maps (DLR, 2025) and Digisonde stations data (GIRO, 2025) in areas near Beirut. This investigation is expected to reveal ionospheric disturbances related with ROTI increase in respect to the daily ROTI median near Cyprus and a possible Medium Scale Traveling Ionospheric Disturbance (MSTID) activity recorded by the Cyprus Digisonde ionograms shortly after the explosion event time. A general assessment of the state of the ionosphere during the specific time interval is also attempted to exclude other influences.

TNA7

IAP

Agata Chuchra

Ionospheric Responses to Geomagnetic Storms: Integrating Observations of the Main Ionospheric Trough, Field-Aligned Currents, and Travelling Ionospheric Disturbances (IREG)

Finished

Affiliation: Space Research Centre of Polish Academy of Sciences, Polan

Abstract: The Ionospheric Responses to Geomagnetic Storms (IREG) research project examined the effects of two geomagnetic storms (7–8 October 2015 driven by Corotating Interaction Region (CIR) and 7–8 September 2017 driven by Coronal Mass Ejection (CME)) on the ionosphere, focusing on the potential relationships between the main ionospheric trough (MIT), field-aligned currents (FACs), and travelling ionospheric disturbances (TIDs). FACs are electric currents that flow along geomagnetic field lines, facilitating energy transfer between the magnetosphere and ionosphere, MIT is a region of significantly reduced electron density occurring at mid-latitudes (45º-67º), while TIDs are wave-like ionospheric disturbances that propagate through the ionosphere and can be triggered by lower atmospheric weather conditions, auroral precipitation, and thermal effects from ionospheric currents. Large-scale TIDs are considered as ionospheric signatures of the magnetosphere-ionosphere-thermosphere coupling processes during space weather events. FAC variability can drive plasma instabilities and ionospheric irregularities, and cause energy dissipation by Joule heating leading to localized plasma density perturbations that may develop into TIDs and, through these processes, influence MIT's characteristics. Ionograms from Pruhonice and Juliusruh digisonde stations were analysed using SAO Explorer, revealing cases of TIDs, including multi-cusp and forked F2 layer structures, during both storms. The findings suggest that, during geomagnetic disturbances, intensified FACs enhance auroral heating, which can launch TIDs propagating toward mid-latitudes and potentially affect the MIT. This study benefited from access to expert guidance, specialized software tools, and ionospheric monitoring infrastructure provided by the PITHIA-NRF TNA program at the Institute of Atmospheric Physics (IAP). The project strengthened expertise in digisonde data interpretation and advanced methodologies for detecting TIDs, contributing to the broader study of space weather impacts on the ionosphere.

TNA8

OE

Sivakandan Mani 

Exploration on the Impact of Solar Variabilities on TID Occurrence Characteristics using Ionospheric Tilt Measurements (ExSoTIDs)

Finished

Affiliation: Leibniz Institute of Atmospheric Physics at the University of Rostock, Germany

Abstract: Traveling ionospheric disturbances (TIDs) are wave-like perturbations in plasma density that can be broadly classified into two categories: 1) Large-Scale TIDs (LSTIDs) and 2) Medium-Scale TIDs (MSTIDs). LSTIDs are frequently observed during disturbed geomagnetic conditions, while MSTIDs arise from various sources, including severe tropospheric convection, jet streams, earthquakes, tsunamis, E-F region coupling, and geomagnetic disturbances. This variety of sources makes forecasting MSTIDs a complex task. Additionally, the occurrence and propagation characteristics of MSTIDs vary depending on the time of day, location, season, and levels of solar activity. However, the relationship between solar activity and MSTIDs in the European sector has not been thoroughly explored.

MSTIDs can lead to significant ionospheric plasma density gradients, which are particularly important for High Frequency (HF) geolocation applications. In these applications, angles of arrival (AoAs) are utilized to determine target positions, making it crucial to understand the presence of these gradients for accurate target localization. To develop a more effective forecasting model, it is essential to quantify the characteristics of MSTIDs. Simultaneous multi-instrument observations, spanning from the troposphere to the ionosphere, will greatly aid in this effort. Recent studies have shown that measuring ionospheric tilt using the DSP-4 ionosonde is an effective method for investigating TIDs. Consequently, this project aims to explore the impact of solar variability on the occurrence and propagation characteristics of TIDs through ionospheric tilt measurements and model simulations.

TNA8

NOA

Ola Ahmed Mustafa Abu Elezz 

Comparative Analysis of Topside Ne-Profiles: NeQuick2 and 3D EDD Models Against Radio Occultation Measurements Over Europe (CATNPRO)

Finished

Affiliation: Space Weather Monitoring Center, Physics Department, Helwan University, Egypt

Abstract: Constructing the ionospheric electron density profile accurately is still a significant challenge for radio wave propagation research and space weather monitoring. In this work, we assess the performance of the 3D electron density reconstruction models provided in PITHIA-NRF eSC. The first model is NeQuick2, and the second model is the 3D version of the TaD model. Both models use the bottomside maps updated with the Digisonde vertical electron density profiles and therefore their performance up to the hmF2 is identical. Models’ discrepancies in the topside region are due to insufficient constraints above the F2-layer peak. To assess the performance of the models we compare the resulted reconstructed profiles with independent datasets obtained from Radio Occultation profiles (e.g., COSMIC/FORMOSAT-3 radio occultation). The study is focusing on defining the comparison methodology and applying to a case study under quiet ionospheric conditions. The comparison leads to some conclusions regarding the capacity of the reconstruction models to reproduce the various ionospheric layers, and mainly the F2 layer, with a realistic estimation of the density gradients and thickness, in both its bottomside and topside parts.

TNA8

SGO

Liliana Macotela 

Field Work Towards an Updated Kannuslehto VLF Receiver (LOUVRE)

Finished

Affiliation: Norwegian Research Centre, Norway

Abstract: ELF-VLF (3 Hz – 30 kHz) radio waves can propagate through a magnetized plasma in what is known as the whistler mode. These waves can originate from various sources, including lightning discharges in the troposphere, natural wave-particle interactions in the magnetosphere, or interactions triggered by artificial, man-made signals. Since the deployment of the Kannuslehto VLF receiver, no hardware upgrades have been made, and many of its electrical components are now outdated. Furthermore, the lack of backup components makes the system vulnerable in the event of antenna failure or required maintenance. Maintaining the Kannuslehto receiver’s capability to detect newly reported and diverse wave structures is crucial. Namely, a continuous broadband recording in the 0.2–39 kHz frequency range, a measurement sampling of at least 78.125 kHz, almost flat spectral response, signal-to-noise ratio, and a threshold of sensitivity of about 0.1 fT in each 1 Hz bandwidth within that range, i.e., a receiver noise level of ∼10−14 nT2/Hz. To address these challenges, members of the LOUVRE project suggest to test using a Multifunction I/O Device named USB-6421 in a modular VLF receiver system. A modular system enhances both the resilience and adaptability of a receiving antenna.