TNA Project Overview

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

Within the Trans-National Access programme of the PITHIA-NRF framework dr. Doornbos and dr. Van Dam from KNMI have visited INGV between 21–25 March 2022 to work with dr. Cesaroni and dr. Spogli on ionosphere measurements. This report describes the outcomes of this visit. The goal of the project is to compare KNMI’s GNSS receiver data in the Caribbean with INGV and DLR data, and to learn about INGV data calibration techniques. Both objectives have been met. Using INGV calibration software the receiver output has been validated and some first scientific results have been obtained. These include observing ionospheric disturbance due to the Tonga volcanic eruption and observing the ionospheric response to a solar flare. As of 5 May 2022 KNMI’s scintillation data is shared with INGV as the receivers increase the global coverage of the INGV network which is used in the PECASUS collaboration (in which KNMI also participates). Plans for future collaboration have been discussed.

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.

In the recent years, we discovered that many nightglow emissions are polarised. This opens a new window on our space environment. In particular, it allows to follow the evolution of the electron density in the upper atmosphere, and maybe more important, the electric currents that flow either parallel or perpendicularly to the magnetic field.

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.

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

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

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.

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.

IAP

Tamás Bozóki

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

Finished

 NOA

Sivakandan Mani

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

 Finished

OE

Attila Buzás

SOlar Flare-induced Absorption in the ionosphere Research– SOFAR

Finished

INGV

Ola Ahmed Mustafa Abu Elezz

Validating the Swarm S4 index over Africa using Eswua database

In progress

CBK-PAS

Oyuki Chang

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

In progress

EISCAT

Anna-Marie Bals

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

 In progress