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1. Regional Spatial Mean of Ionospheric Irregularities Based on K-Means Clustering of ROTI Maps.

Author

Migoya-Orué, Yenca, Abe, Oladipo E., and Radicella, Sandro

Subjects
IONOSPHERIC plasma, K-means clustering, MACHINE learning, MATHEMATICAL optimization, LONGITUDE
Abstract

In this paper, we investigate and propose the application of an unsupervised machine learning clustering method to characterize the spatial and temporal distribution of ionospheric plasma irregularities over the Western African equatorial region. The ordinary Kriging algorithm was used to interpolate the rate of change of the total electron content (TEC) index (ROTI) over gridded 0.5° by 0.5° latitude and longitude regional maps in order to simulate the level of ionospheric plasma irregularities in a quasi-real-time scenario. K-means was used to obtain a spatial mean index through an optimal stratification of regional post-processed ROTI maps. The results obtained could be adapted by appropriate K-means algorithms to a real-time scenario, as has been performed for other applications. This method could allow us to monitor plasma irregularities in real time over the African region and, therefore, lead to the possibility of mitigating their effects on satellite-based location systems in the said region. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Contributors

Author

Chalkias, Christos, primary, Chandra Pandey, Prem, additional, de Oliveira Moraes, Alison, additional, Efthimiadou, Aspasia, additional, Faka, Antigoni, additional, Fernandes Breder, Victor Hugo, additional, Ferreira, V.G., additional, Galera Monico, João Francisco, additional, Grigorakakis, Grigoris, additional, José dos Santos Freitas, Moisés, additional, Kalogeropoulos, Kleomenis, additional, Katsenios, Nikolaos, additional, Kokinou, Eleni, additional, Kumar, Amit, additional, Kumar, Pavan, additional, Kumar, Sanjay, additional, Kumar, Shubham, additional, Lal, Preet, additional, Lau, Lawrence, additional, Lemieszewski, Łukasz, additional, Maciuk, Kamil, additional, Mall, R.K., additional, Martínez-Guanter, Jorge, additional, Migoya-Orué, Yenca O., additional, Montecino, H.D., additional, Narbudowicz, Adam, additional, Ndehedehe, C.E., additional, Ochin, Evgeny, additional, Pandey, Manish Kumar, additional, Papadopoulou, Zoi, additional, Pearson, Alastair, additional, Perez-Ruiz, Manuel, additional, Petropoulos, George P., additional, Radicella, Sandro M., additional, Rao, S.S., additional, Rodrigues de Paula, Eurico, additional, Saikia, Purabi, additional, Salles, Lucas Alves, additional, Schaefer, Martin, additional, Sha, Hao, additional, Sharma, Jyoti Kumar, additional, Singh, A.K., additional, Singh, R.P., additional, Soghoyan, Arpine, additional, Sparangis, Panagiotis, additional, Srivastava, Prashant K., additional, Stathopoulos, Nikolaos, additional, Sun, Baohua, additional, Tiwari, Prasoon, additional, Triantakonstantis, Dimitris, additional, Tripathi, Amit Kumar, additional, Tsatsaris, Andreas, additional, Tserpes, Konstantinos, additional, Upadhyaya, Shrini K., additional, Vani, Bruno César, additional, Vidalis-Kelagiannis, Michalis, additional, Xu, T., additional, Yang, Lin, additional, and Yuan, P., additional

Published
2021
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9. Contributors

Author

Abdu, Managlathayil Ali, primary, Alfonsi, Lucilla, additional, Bhatt, Asti, additional, Carter, Brett, additional, Coleman, Christopher J., additional, Consolini, Giuseppe, additional, Coster, Anthea J., additional, Erickson, Philip J., additional, Forte, Biagio, additional, Hysell, D.L., additional, Knepp, Dennis L., additional, Lapenta, Giovanni, additional, Maruyama, Naomi, additional, Materassi, Massimo, additional, Mendillo, Michael, additional, Michelis, Paola De, additional, Nava, Bruno, additional, Piersanti, Mirko, additional, Radicella, Sandro M., additional, Semeter, Joshua, additional, Silberfarb, Andrew, additional, Skone, Susan, additional, Spogli, Luca, additional, and Tozzi, Roberta, additional

Published
2020
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13. Study of ionosphere irregularities over the Iberian Peninsula during two moderate geomagnetic storms using GNSS and ionosonde observations

Author

Campuzano, Saioa A., Delgado-Gómez, Fernando, Migoya-Orué, Yenca, Rodríguez-Caderot, Gracia, Herraiz Sarachaga, Miguel, Radicella, Sandro M., Campuzano, Saioa A., Delgado-Gómez, Fernando, Migoya-Orué, Yenca, Rodríguez-Caderot, Gracia, Herraiz Sarachaga, Miguel, and Radicella, Sandro M.

Abstract

© 2023 by the authors. This research was funded by Ministry of Science and Innovation from Spanish Government, grant number IJC2020-044990-I and the APC was funded by Atmosphere (MDPI)., Studies on the irregularities of the ionosphere during disturbed geomagnetic conditions are fundamental to understanding the complex dynamics taking place in the upper atmosphere. In this work, different data sources are used to study the ionosphere effects of two moderate geomagnetic storms, 26-27 February 2014 and 17-18 September 2021, over the Iberian Peninsula. Data are obtained from digital ionosondes in Spain, Italy and Greece; the 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 the UPC Quarter-of-an-hour time resolution Rapid GIM (UQRG), vertical TEC global ionosphere maps (GIMs), produced at 15 min intervals by the Universitat Politecnica de Catalunya (UPC, Spain). This analysis showed that, during the two moderate storms, spread-F and high values of ROTI, indicating the presence of irregularities, are found in a very localized area (Southern Iberian Peninsula and northwest Africa) and local times (night-time). However, no irregularities are found eastwards and northwards of the location indicated. We propose some possible explanations for these observations for both the storms, one of them related to the position of the Equatorial Ionosphere Anomaly (EIA) and the other one attributed to the Perkins' instabilities., Ministerio de Ciencia e Innovación, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

Published
2023

14. Development of research capacities in space weather: a successful international cooperation

Author

Amory-Mazaudier Christine, Radicella Sandro, Doherty Patricia, Gadimova Sharafat, Fleury Rolland, Nava Bruno, Anas Emran, Petitdidier Monique, Migoya-Orué Yenca, Alazo-Cuartas Katy, and Shiokawa Kazuo

Subjects
capacity building in space weather in africa, equatorial geophysics, global navigation satellite system, Meteorology. Climatology, QC851-999
Abstract

This paper presents an international cooperation which has successfully developed research capacities in the scientific disciplines of sun–earth relations and space weather in many countries over the world during the past decades. This success was based on the deployment of scientific instruments in countries that did not have them, on the sharing of knowledge and research tools, on thesis supervision and on the integration of researchers trained in their country. This article will only focus on aspects of training conducted by ICTP, Boston College, ICG, SCOSTEP and GIRGEA. We will highlight what has been enhanced in international cooperation to achieve this success and what remains to be done.

Published
2021
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22. Ionosphere/Positioning and Telecommunications

Author

Radicella, Sandro M., Burton, W.B., editor, Bertola, F., editor, Cassinelli, J.P., editor, Cesarsky, C.J., editor, Ehrenfreund, P., editor, Engvold, O., editor, Heck, A., editor, Heuvel, E.P.J. van Den, editor, Kaspi, V.M., editor, Kuijpers, J.M.E., editor, van Der Laan, H., editor, Murdin, P.G., editor, Pacini, F., editor, Radhakrishnan, V., editor, Somov, B.V., editor, Sunyaev, R.A., editor, and Lilensten, Jean, editor

Published
2007
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37. Recent advances in atmospheric, solar-terrestrial physics and space weather from a north-south network of scientist [2006-2016] Part B: results and capacity building

Author

Amory-Mazaudier, Christine, Fleury, Rolland, Petitdidier, Monique, Soula, Serge, Masson, Frédéric, Davila, Jospeh, Doherty, Patricia, Elias, Ana Georgina, Gadimova, Sharafat, Makela, Jonathan, Nava, Bruno, Radicella, Sandro Maria, Richardson, John, Touzani, Abderrahmane, Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Abdus Salam International Centre for Theoretical Physics [Trieste] (ICTP), Lab-STICC_IMTA_MOM_PIM, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Département Micro-Ondes (IMT Atlantique - MO), IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA, Boston College (BC), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET), United nations office for outer space affairs (United Nation office at vienna) (UNOOSA), University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology (MIT), Centre régional africain des sciences et technologies de l'espace en langue française (Organisation des Nations Unies) (CRASTE-LF), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Equatorial electrojet year (IEEY), Space weather, international space weather initiative project (ISWI), [SDU]Sciences of the Universe [physics], International Heliophysical Year (IHY), International heliophysical (IHY), [SPI.TRON]Engineering Sciences [physics]/Electronics
Abstract

International audience; This paper reviews scientific advances achieved by a North-South network between 2006 and 2016. These scientific advances concern solar terrestrial physics, atmospheric physics and space weather. This part B is devoted to the results and capacity building. Our network began in 1991, in solar terrestrial physics, by our participation in the two projects: International Equatorial Electrojet Year IEEY [1992-1993] and International Heliophysical Year IHY [2007-2009]. These two projects were mainly focused on the equatorial ionosphere in Africa. In Atmospheric physics our research focused on gravity waves in the framework of the African Multidisciplinary Monsoon Analysis project n°1 [2005-2009 ], on hydrology in the Congo river basin and on lightning in Central Africa, the most lightning part of the world. In Vietnam the study of a broad climate data base highlighted global warming. In space weather, our results essentially concern the impact of solar events on global navigation satellite system GNSS and on the effects of solar events on the circulation of electric currents in the earth (GIC). This research began in the framework of the international space weather initiative project ISWI [2010-2012]. Finally, all these scientific projects have enabled young scientists from the South to publish original results and to obtain positions in their countries. These projects have also crossed disciplinary boundaries and defined a more diversified education which led to the training of specialists in a specific field with knowledge of related scientific fields.

Published
2017

40. Solar cycle variations in the ionosphere of Mars

Author

Sánchez-Cano, Beatriz, Lester, Mark, Witasse, Olivier, Blelly, Pierre-Louis, Cartacci, Marco, Radicella, Sandro M., and Herraiz Sarachaga, Miguel

Subjects
Meteorología, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Geofísica, Physics::Geophysics
Abstract

Solar cycle variations in solar radiation create notable changes in the Martian ionosphere, which have been analysed with Mars Express plasma datasets in this paper. In general, lower densities and temperatures of the ionosphere are found during the low solar activity phase, while higher densities and temperatures are found during the high solar activity phase. In this paper, we assess the degree of influence of the long term solar flux variations in the ionosphere of Mars.

Published
2016

41. Ionospheric and magnetic signatures of a high speed solar wind in low latitudes on 13 October 2012

Author

Migoya-Orué, Yenca, Azzouzi, Ilyasse, Coisson, Pierdavide, Amory-Mazaudier, Christine, Fleury, Rolland, Radicella, Sandro M., Abdus Salam International Centre for Theoretical Physics [Trieste] (ICTP), Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Mohammed V, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Département Micro-Ondes (MO), Université européenne de Bretagne - European University of Brittany (UEB)-Télécom Bretagne-Institut Mines-Télécom [Paris] (IMT), Lab-STICC_TB_MOM_PIM, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Mohammed V de Rabat [Agdal] (UM5), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-École polytechnique (X)-Sorbonne Universités-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), and Institut Mines-Télécom [Paris] (IMT)-Télécom Bretagne-Université européenne de Bretagne - European University of Brittany (UEB)

Subjects
solar wind, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], geomagnetic storm, geomagnetic field, equatorial ionosphere, ionospheric disturbance dynamo, F layer
Abstract

International audience; This paper presents the impact of a fast solar wind on the ionosphere, in low latitudes, on 13 October 2012. On that day, the high speed solar wind reached the Earth around 16:00UT, during the recovery phase of a geomagnetic storm which started around 00:00UT. The solar wind speed was determined to be 580km/s, on the same day, around 17:00UT. Its impact was observed in low and equatorial latitudes, in Africa and in Eastern South America, on the F layer and on the geomagnetic field variations. Through the analysis of magnetic indices, ionosonde characteristics and the horizontal component of the geomagnetic field, we found that the 13 October 2012 event exhibited a local impact, affecting the observatories situated in a longitude sector between 315°E and 45°E. Particularly, the F layer in Africa (observed by the ionosonde at Ascension Island) did not present any lift, and there was a delay for approximately two hours of the ascent of the F layer in America (the ionosonde at Fortaleza). In this case, there was an evident inhibition on the development of spread F at the time of the Pre Reversal Enhancement (PRE) in Africa and Eastern America, while the ionograms of the days before and after presented clear spread F traces. The disturbances of the ionospheric equivalent electric current (Diono) deduced from the variations of the geomagnetic field at M'Bour near Dakar (Africa) and at Kourou (Eastern America) exhibited on the dayside, an anti Sq current which is signature of the influence of the Disturbance Dynamo Electric Field (DDEF).

Published
2016

44. Total electron content in the Martian atmosphere: A critical assessment of the Mars Express MARSIS data sets

Author

Sánchez-Cano, Beatriz, Morgan, D. D., Witasse, O., Radicella, Sandro M., Herraiz Sarachaga, Miguel, Orosei, R., Cartacci, M., Cicchetti, A., Noschese, R., Kofman, W., Grima, C., Mouginot, J., Gurnett, D. A., Lester, M., Blelly, P. L., Opgenoorth, H., Quinsac, G., ITA, USA, GBR, FRA, ESP, NLD, and SWE

Subjects
Total electron content, Astronomi, astrofysik och kosmologi, Martian ionosphere, TEC data sets, total electron content, Astronomy, Astrophysics and Cosmology, Mars Express, MARSIS TEC assessment
Abstract

©2015. The Authors. The total electron content (TEC) is one of the most useful parameters to evaluate the behavior of the Martian ionosphere because it contains information on the total amount of free electrons, the main component of the Martian ionospheric plasma. The Mars Express Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) radar is able to derive TEC from both of its operation modes: (1) the active ionospheric sounding (AIS) mode and (2) the subsurface mode. TEC estimates from the subsurface sounding mode can be computed from the same raw data independently using different algorithms, which should yield similar results. Significant differences on the dayside, however, have been found from two of the algorithms. Moreover, both algorithms seem also to disagree with the TEC results from the AIS mode. This paper gives a critical, quantitative, and independent assessment of these discrepancies and indicates the possible uncertainty of these databases. In addition, a comparison between the results given by the empirical model of the Martian ionosphere developed by Sánchez-Cano et al. (2013) and the different data sets has been performed. The main result is that for solar zenith angles higher than 75, where the maximum plasma frequency is typically small compared with the radar frequencies, the two subsurface algorithms can be confidently used. For solar zenith angles less than 75, where the maximum plasma frequency is very close to the radar frequencies, both algorithms suffer limitations. Nevertheless, despite the solar zenith angle restrictions, the dayside TEC of one of the two algorithms is consistent with the modeled TEC. Key Points Critical assessment of the TEC from Mars Express MARSIS instrument TEC from subsurface algorithms and active ionospheric sounding comparison MARSIS data sets evaluation by NeMars empirical model

Published
2015

45. Precise point positioning performance in the presence of the 28 October 2003 sudden increase in total electron content

Author

Rodríguez Bilbao, I., Radicella, Sandro M., Rodríguez-Caderot, G., Herraiz Sarachaga, Miguel, and Ministerio de Economía y Competitividad (España)

Subjects
SITEC, PPP, Impacts on technological systems, Ionospheric disturbances, Solar effects, Ionospheric effects on radio waves
Abstract

Intense disturbances in the ionosphere may produce perturbations in Global Navigation Satellite Systems (GNSS) radio signals that in the most severe cases produce receiver tracking problems, which in turn impact on GNSS positioning accuracy. In this paper we present a case study related to the sudden increase in total electron content (SITEC) induced by the X17.2 solar flare that occurred on 28 October 2003. This is the largest SITEC ever recorded by means of the rate of change of total electron content. A solar radio burst (SRB) occurred in the same period which caused GNSS signal fading and in some cases complete signal loss. Although SITEC contribution to the signal noise cannot be separated from that of SRB, in this paper we show that accuracy degradation may happen in kinematic precise point positioning (PPP) in several stations of the sunlit hemisphere when 30 s sampling rate data are analyzed. The observed errors in the position are the result of the difficulties that cycle slip (CS) detection strategies have to deal with the observables that have been affected by the SITEC., MINECO. Grant Number: AYA2013-47735-P; Department of Education, Language Policy and Culture of the Basque Government; Spanish Ministry of Education, Culture and Sports

Published
2015

46. Behavior of the ionosphere over Europe during two geomagnetic storms which caused tongues of ionization over North America

Author

Rodríguez-Bouza, M., Herraiz Sarachaga, Miguel, Rodríguez-Caderot, G., and Radicella, Sandro M.

Subjects
Ionosfera, Geomagnetic storms, Ionosphere, Tormentas geomagnéticas
Abstract

Poster presentado en la EGU General Assembly 2015, 12-17 April, 2015, Vienna, Austria, This work presents the effect of two geomagnetic storms on the ionospheric total electron content (TEC) over Europe. Those geomagnetic storms occurred on July 14th, 2013 and February 19th, 2014 and originated a tongue of ionization over North America. Following the criteria of Gonzalez et al.(1994), the July storm can be classified as a moderate one because the Dst index reached a value of -72nT, whereas the February storm as an intense event considering that Dst index dropped to -112nT. For this study we have used RINEX files obtained from GNSS stations belonging to International GPS Service, IGS, EUREF Permanent Network, and University Navstar Consortium, UNAVCO, networks. The data has been divided into two groups in function of the region: Europe or North America. For each group we have used all the available stations. The RINEX files have been processed using a technique developed by Ciraolo (2012) which assumes the ionospheric thin shell model to obtain the vertical total electron content (vTEC) from the slant total electron content (sTEC) at the Ionospheric Pierce Point, IPP, the point where the line-of-sight between the satellite and the ground receiver intersects the ionosphere. The data were obtained at 1 minute sampling in periods of geomagnetic storms and quiet days close to them. In both storms a tongue of ionization, ToI, appeared over North America from afternoon to dusk (between 19:00 and 3:00 GMT). The behavior of the ionosphere over Europe was very different in eachcase. In July, the TEC decreased respect the quiet days during the ToI time. In the February storm the behavior of the ionosphere over Europe was similar to that of a quiet day but the following day appeared a phenomenom similar to the ToI.

Published
2015

47. A Physical Numerical Ionospheric Model and Its Simulation Results

Author

Zhang Man-Lian, M Radicella Sandro, and Shang She-Ping

Subjects
Physics, Momentum (technical analysis), Physics and Astronomy (miscellaneous), Meteorology, QUIET, Physics::Space Physics, Boundary value problem, Geophysics, Ionosphere
Abstract

This paper describes the construction of a one-dimensional time-dependent theoretical ionospheric model, which is based on numerical solution of continuity and momentum equations for , and NO+. The model is designed to have an option to incorporate the observational ionospheric characteristic parameters into the numerical model to indirectly determine the upper boundary condition when solving the transport equations of O+. A preliminary simulation result of the model when used to simulate the ionosphere during April 18 ~ May 10, 1998, which includes both quiet and disturbed periods, showed that the model constructed is able to reproduce the observational results reasonably well both for quiet and disturbed periods.

Published
2004
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48. Precise point positioning performance in the presence of the 28 October 2003 sudden increase in total electron content

Author

Ministerio de Economía y Competitividad (España), Rodríguez Bilbao, I., Radicella, Sandro M., Rodríguez-Caderot, G., Herraiz Sarachaga, Miguel, Ministerio de Economía y Competitividad (España), Rodríguez Bilbao, I., Radicella, Sandro M., Rodríguez-Caderot, G., and Herraiz Sarachaga, Miguel

Abstract

Intense disturbances in the ionosphere may produce perturbations in Global Navigation Satellite Systems (GNSS) radio signals that in the most severe cases produce receiver tracking problems, which in turn impact on GNSS positioning accuracy. In this paper we present a case study related to the sudden increase in total electron content (SITEC) induced by the X17.2 solar flare that occurred on 28 October 2003. This is the largest SITEC ever recorded by means of the rate of change of total electron content. A solar radio burst (SRB) occurred in the same period which caused GNSS signal fading and in some cases complete signal loss. Although SITEC contribution to the signal noise cannot be separated from that of SRB, in this paper we show that accuracy degradation may happen in kinematic precise point positioning (PPP) in several stations of the sunlit hemisphere when 30 s sampling rate data are analyzed. The observed errors in the position are the result of the difficulties that cycle slip (CS) detection strategies have to deal with the observables that have been affected by the SITEC.

Published
2015

49. A prototype of a quick Information System for Space Weather Events effects on the ionosphere

Author

Herraiz Sarachaga, Miguel, Moreno Monge, B., Rodríguez-Bouza, M., Rodríguez-Bilbao, I., Rodríguez-Caderot, G., and Radicella, Sandro M.

Subjects
Physics::Space Physics, Geomagnetic Storms, Tormentas geomagnéticas, Physics::Atmospheric and Oceanic Physics, Physics::Geophysics
Abstract

We present a prototype of a Quick Information System aimed at warning about the ionospheric effects following a geomagnetic storm and based on the daily analysis of the ionospheric behaviour. A geomagnetic storm can produce an ionospheric storm characterized by a variation of the electron density of the ionosphere. As these perturbations cause negative effects on transionospheric communications and satellite positioning errors (Buonsanto, 1999), the development of resources oriented to alert to the ionospheric anomalous situation appears as a valuable task.

Published
2013

50. An investigation of the ionospheric F region near the EIA crest in India using OI 777.4 and 630.0nm nightglow observations.

Author

Parihar, Navin, Radicella, Sandro Maria, Nava, Bruno, Migoya-Orue, Yenca Olivia, Tiwari, Prabhakar, and Singh, Rajesh

Subjects
*IONOSPHERIC techniques, *LATITUDE, *NIGHTGLOW (Atmospheric radiation), *ELECTRON density
Abstract

Simultaneous observations of OI 777.4 and OI 630.0 nm nightglow emissions were carried at a low-latitude station, Allahabad (25.5° N, 81.9° E; geomag. lat. ~16.30° N), located near the crest of the Appleton anomaly in India during September-December 2009. This report attempts to study the F region of ionosphere using airglow-derived parameters. Using an empirical approach put forward by Makela et al. (2001), firstly, we propose a novel technique to calibrate OI 777.4 and 630.0 nm emission intensities using Constellation Observing System for Meteorology, Ionosphere, and Climate/Formosa Satellite Mission 3 (COSMIC/FORMOSAT-3) electron density profiles. Next, the electron density maximum (Nm) and its height (hmF2) of the F layer have been derived from the information of two calibrated intensities. Nocturnal variation of Nm showed the signatures of the retreat of the equatorial ionization anomaly (EIA) and the midnight temperature maximum (MTM) phenomenon that are usually observed in the equatorial and lowlatitude ionosphere. Signatures of gravity waves with time periods in the range of 0.7-3.0 h were also seen in Nm and hmF2 variations. Sample Nm and hmF2 maps have also been generated to show the usefulness of this technique in studying ionospheric processes. [ABSTRACT FROM AUTHOR]

Published
2018
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