Assessment of the capabilities and applicability of ionospheric perturbation indices provided in Europe

© 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Perturbations in the ionosphere are of great interest not only for scientific research, but also for applications using transionospheric radiosignals (e.g. GNSS applications and HF communication), because the transmission of radiosignals is sensitive to the electron density in the ionosphere. However, ionospheric perturbations have manifold character. Their spatial range can vary between global and very local effects (a few hundreds of km range) and their temporal range varies between seconds and days. All these perturbations have different physical background and different impact on applications. Many ionosphere perturbation indices that characterize the state of ionospheric perturbations have been introduced in the past (e.g. ROTI, S4, , AATR, Reff, W-index, SISTED, SOLERA, DIXSG, IBI, Dfu/Dfl, etc.). This manuscript is an assessment of a subset of diverse ionospheric indices developed and/or applied in Europe. It describes the objectives of the indices, demonstrates their character in a case study for September 2017, indicates their applicability for different use cases in science and industry and guides users to find the appropriate index for their purposes.Peer ReviewedPostprint (published version

Report on TID algorithms

This deliverable presents the TID detection algorithms as improved in response to design principles stated in T2.1 and their testing in the lab environment, verification against measurements taken during quiet and disturbed periods of time, benchmarking for their transition to operations, and final validation to the user requirements of accuracy, timeliness, and coverage.TechTIDE project, funded by the European Commission Horizon 2020 research and innovation program [AD-1], will establish a pre-operational system to demonstrate reliability of a set of TID (Travelling Ionospheric Disturbances) detection methodologies to issue warnings of the occurrence of TIDs over the region extending from Europe to South Africa. TechTIDE warning system will estimate the parameters that specify the TID characteristics and the inferred perturbation, with all additional geophysical information to the users to help them assess the risks and to develop mitigation techniques, tailored to their application. This document is TechTIDE D2.2 “Report on the TID algorithms” and it is an output of TechTIDE Task 2.2 (Development of the TID identification algorithms and products) of the WP2 (TID identification methodologies) which has the final goal to release the basic algorithms for the TID identification and to test a first version of the value-added products for implementation in the TechTIDE warning system. The document highlights four aspects of the TID algorithm release process, (1) Developmentbased on the concept, techniques, and algorithms as stated in TechTIDE D2.1, (2) Verification, an internal testing process that ensures algorithm correctness, (3) Benchmarkingneeded to prepare algorithms to transition to operations, and (4) Validation, an external process of ensuring that developed algorithms are compliant with the stated end user expectations.Postprint (published version

Nowcasting, forecasting and warning for ionospheric propagation: tools and methods

The paper reviews the work done in the course of the COST 271 Action concerned with the development of tools and methods for forecasting, nowcasting and warning of ionospheric propagation conditions. Three broad categories of work are covered. First, the maintenance and enhancement of existing operational services that provide forecast or nowcast data products to end users; brief descriptions of RWC Warsaw and the STIF service are given. Second, the development of prototype or experimental services; descriptions are given of a multi-datasource system for reconstruction of electron density profiles, and a new technique using real-time IMF data to forecast ionospheric storms. The third category is the most wide-ranging, and deals with work that has presented new or improved tools or methods that future operational forecasting or nowcasting system will rely on. This work covers two areas - methods for updating models with prompt data, and improvements in modelling or our understanding of various ionospheric-magnetospheric features - and ranges over updating models of ionospheric characteristics and electron density, modelling geomagnetic storms, describing the spatial evolution of the mid-latitude trough, and validating a recently-proposed technique for deriving TEC from ionosonde observations

pilot ionosonde network for identification of traveling ionospheric disturbances

Travelling Ionospheric Disturbances (TIDs) are the ionospheric signatures of atmospheric gravity waves (AGWs). Their identification and tracking is important because the TIDs affect all services that rely on predictable ionospheric radio wave propagation. Although various techniques have been proposed to measure TID characteristics, their real-time implementation still has several difficulties. In this contribution, we present a new technique, based on the analysis of oblique Digisonde-to-Digisonde (D2D) "skymap" observations, to directly identify TIDs and specify the TID wave parameters based on the measurement of angle-of-arrival, Doppler frequency, and time-of-flight of ionospherically reflected high-frequency (HF) radio pulses. The technique has been implemented for the first time for the Net-TIDE project with data streaming from the network of European Digisonde DPS4D observatories. The performance is demonstrated during a period of moderate auroral activity, assessing its consistency with independent measurements such as data from auroral magnetometers and electron density perturbations from Digisondes and GNSS stations. Given that the different types of measurements used for this assessment were not made at exactly the same time and location, and that there was insufficient coverage in the area between the AGW sources and the measurement lo cations, we can only consider our interpretation as plausible and indicative for the reliability of the extracted TID characteristics. In the framework of the new TechTIDE project (European Commission H2020), a retrospective analysis of the Net-TIDE results in comparison with those extracted from GNSS TEC-based methodologies is currently being attempted, and the results will be the objective of a follow up paper

Validation of Ionospheric Specifications During Geomagnetic Storms: TEC and foF2 During the 2013 March Storm Event

To address challenges of assessing space weather modeling capabilities, the CommunityCoordinated Modeling Center is leading a newly establishedInternational Forum for Space WeatherModeling Capabilities Assessment. This paper presents preliminary results of validation of modeled foF2 (F2 layer critical frequency) and TEC (total electron content) during the first selected 2013 March storm event (17 March 2013). In this study, we used eight ionospheric models ranging from empirical to physics-based, coupled ionosphere-thermosphere and data assimilation models. The quantities we considered are TEC and foF2 changes and percentage changes compared to quiet time background, and the maximum and minimum percentage changes. In addition, we considered normalized percentage changes of TEC. We compared the modeled quantities with ground-based observations of vertical Global Navigation SatelliteSystem TEC (provided by Massachusetts Institute of Technology Haystack Observatory) and foF2 data (provided by Global Ionospheric Radio Observatory) at the 12 locations selected in middle latitudes of the American and European-African longitude sectors. To quantitatively evaluate the models’ performance, we calculated skill scores including correlation coefficient, root-mean square error (RMSE), ratio of the modeled to observed maximum percentage changes (yield), and timing error. Our study indicates that average RMSEs of foF2range from about 1 MHz to 1.5 MHz. The average RMSEs of TEC are between ~5 and ~10 TECU (1 TEC Unit= 1016el/m2). dfoF2[%] RMSEs are between 15% and 25%, which is smaller than RMSE of dTEC[%] ranging from30% to 60%. The performance of the models varies with the location and metrics considered

Toward a reference architecture based science gateway framework with embedded e‐learning support

Science gateways have been widely utilized by a large number of user communities to simplify access to complex distributed computing infrastructures. While science gateways are still becoming increasingly popular and the number of user communities is growing, the fast and efficient creation of new science gateways and the flexibility to deploy these gateways on-demand on heterogeneous computational resources, remain a challenge. Additionally, the increase in the number of users, especially with very different backgrounds, requires intuitive embedded e-learning tools that support all stakeholders to find related learning material and to guide the learning process. This paper introduces a novel science gateway framework that addresses these challenges. The framework supports the creation, publication, selection, and deployment of cloud-based reference architectures that can be automatically instantiated and executed even by nontechnical users. The framework also incorporates a knowledge repository exchange and learning module that provides embedded e-learning support. To demonstrate the feasibility of the proposed solution, two scientific case studies are presented based on the requirements of the plasmasphere, ionosphere, and thermosphere research communities

Space Weather Effects on the Earth’s Upper Atmosphere: Short Report on Ionospheric Storm Effects at Middle Latitudes

During geomagnetic storm events, the highly variable solar wind energy input in the magnetosphere significantly alters the structure of the Earth’s upper atmosphere through the interaction of the ionospheric plasma with atmospheric neutrals. A key element of the ionospheric storm-time response is considered to be the large-scale increases and decreases in the peak electron density that are observed globally to formulate the so-called positive and negative ionospheric storms, respectively. Mainly due to their significant impact on the reliable performance of technological systems, ionospheric storms have been extensively studied in recent decades, and cumulated knowledge and experience have been assigned to their understanding. Nevertheless, ionospheric storms constitute an important link in the complex chain of solar-terrestrial relations. In this respect, any new challenge introduced in the field by a better understanding of the geospace environment, new modeling and monitoring capabilities and/or new technologies and requirements also introduces new challenges for the interpretation of ionospheric storms. This paper attempts a brief survey of present knowledge on the fundamental aspects of large-scale ionospheric storm time response at middle latitudes. Further attention is paid to the results obtained regarding the critical role that solar wind conditions which trigger disturbances may play on the morphology and the occurrence of ionospheric storm effects

Ionospheric forecasts for the European region for space weather applications

This paper discusses recent advances in the implementation and validation of the Solar Wind driven autoregression model for Ionospheric short-term Forecast (SWIF) that is running in the European Digital upper Atmosphere Server (DIAS) to release ionospheric forecasting products for the European region. The upgraded implementation plan expands SWIF’s capabilities in the high latitude ionosphere while the extensive validation tests in the two solar cycles 23 and 24 allow the comprehensive analysis of the model’s performance in all terms. Focusing on disturbed conditions, the results demonstrate that SWIF’s alert detection algorithm forecasts the occurrence of ionospheric storm time disturbances with probability of detection up to 98% under intense geomagnetic storm conditions and up to 63% when storms of moderate intensity are also considered. The forecasts show relative improvement over climatology of about 30% in middle-to-low and high latitudes and 40% in middle-to-high latitudes. This indicates that SWIF is able to capture on average more than one third (35%) of the storm-associated ionospheric disturbances. Regarding the accuracy, the averaged mean relative error during storm conditions usually ranges around 20% in middle-to-low and high latitudes and 24% in the middle-to-high latitudes. Our analysis shows clearly that SWIF alert criteria were designed to effectively anticipate the ionospheric storm time effects that occurred under specific interplanetary conditions, e.g., cloud Interplanetary Coronal Mass Ejections (ICMEs) and/or associated sheaths. The results provide valuable input in advancing our ability in predicting the space weather effects in the ionosphere for future developments, and further work is proposed to enhance the model forecasting efficiency to support operational applications