Validation of a method for ionospheric electron density reconstruction by means of vertical incidence data during quiet and storm periods

A preliminary validation of the technique developed using the NeQuick ionospheric model and the «effective ionization parameter» Az, based on vertical total electron content data ingestion, was carried out in a previous study. The current study was performed to extend the analyzed conditions and confirm the results. The method to validate this technique is based on a comparison between hourly F2 peak values measured with Vertical Incidence (VI) soundings and those calculated with the new technique. Data corresponding to different hours and seasons (equinox, summer solstice, and winter solstice) during the period 2000-2003 (high and medium solar activity conditions) were compared for all available ionosonde stations. The results show a good agreement between foF2 and hmF2 values obtained with the new technique and measurements from vertical incidence soundings during quiet and storms conditions.European Community Fifth Framework Programm

Worst cases for a one-hop high frequency link

The characterisation of a HF channel by means of monthly electron density profiles can be complemented with a detailed study of radio propagation «worst cases» on situations with extremes conditions of radiopropagation for a given period. These «worst cases» correspond to conditions that can be identified by means of cumulative distributions of the key parameter f0F2. This paper analyses the main parameters of the HF channel: time delay, apogee, elevation angle and transmission frequency with mean and extreme conditions. The method used to characterise the ionospheric channel is based on ray-tracing techniques.National Institute of Aerospace Technology (INTA)Dr. Moorhead of Neptune Radar Ltd.Gloucester U.

Inosphere at low latitude: effects on radio signals of satellites recieved in Tucumán

Se mencionan algunos de los efectos que la ionosfera produce en las señales de radio que la atraviesan. Además, se describen las características de la ionosfera ecuatorial y de baja latitud ya que es una de las regiones en donde los sistemas de comunicación y navegación satelital, son más afectados. En particular, se describen estudios sobre el centelleo de señales de satélites recibidas en Tierra. Se muestran resultados de los estudios realizados en Tucumán (26.9o S, 294.6o E), los que podrían ser un aporte para el desarrollo de un sistema de predicción de ocurrencia de las irregularidades ionosféricas que producen el centelleo.Some effects that ionosphere produces on radio signals that traverse it are mentioned. Moreover, the characteristics of the equatorial and low latitude ionosphere are described because it is a region where the communication and navigation satellite systems are strong affected. Particularly, studies on scintillations of satellite signals received at ground are described. The results obtained at Tucumán (26.9° S, 294.6° E) which could be a contribution to develop a system to predict the occurrence of ionospheric irregularities that produce scintillations are also shown.Fil: Ezquer, Rodolfo Gerardo. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionósfera; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Radicella, Sandro María. Universidad Tecnológica Nacional; Argentin

Aplicaciones en la investigación ionosférica de datos procedentes de sondeos de incidencia vertical y receptores GPS

En la actualidad, existen diversos Centros de Datos Ionósfericos accesibles a través de Internet. Uno de estos centros ha sido desarrollado por la Universidad de Massachusetts-Lowell. El conjunto de características ionosféricas (foF2, foF1, M(3000)F2, etc) junto con los perfiles de densidad electrónica provenientes de un elevado número de digisondas extendidas por todo el mundo, están disponibles on-line mediante el software diseñado por este Centro. Una visión complementaria de la Ionosfera se puede obtener mediante observaciones recogidas por la red mundial de receptores GPS. A través de estas dos fuentes de datos es posible desarrollar numerosos estudios y permiten abrir una gama amplia de aplicaciones. En este trabajo se abordan de forma resumida algunas investigaciones realizadas recientemente a partir de estos datos por los autores de este artículo

Day-to-day changes in experimental electron density profiles and their implications to IRI model

The electron density variability at fixed heights is studied for use in the International Reference Ionosphere IRI model. Monthly median, upper and lower quartile values were obtained f o F2, hmF2, B0 and B1 as deduced from ionograms. The IRI electron density profiles established with these values were then compared with the median and quartiles at fixed heights. Results are shown for the three ionospheric stations E1 Arenosillo (37.1 N, 353.3 E), Tucuman (26.9 S, 294.6 E) and San Juan (31.5 S, 290.4 E) as a function of solar activity, season and local time. As found by other authors the height of maximum variability, hvmax, is located below the peak electron density height (hmF2) in all the cases. Values of differences between hmF2 and hvmax. are analized. Variability defined as the interquartile difference and hvmax results are calculated from experimental electron density profiles measured at the three stations.Fil: Amarante, G. Miró. Centro Internacional Abdus Salam de Física Teórica​; ItaliaFil: Santamaría, M. Cueto. Universidad Complutense de Madrid; EspañaFil: Mosert, Marta Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Radicella, Sandro María. Centro Internacional Abdus Salam de Física Teórica​; ItaliaFil: Ezquer, Rodolfo Gerardo. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionósfera; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin

On the time of minimum ionization in the F2 region

Using measurements of the critical frequency of F2 region (foF2) the validity of the International Reference Ionosphere model to predict the time of minimum ionization is checked. Data obtained at different ionospheric stations have been considered. The CCIR and URSI options are used to model calculations. For CCIR option the results show that good predictions were obtained for about 40% of the considered cases. For the rest of the considered data, the model predicts the minimum at times earlier than that observed in the measurements. The percentages of good predictions obtained with URSI option are lower than those corresponding to CCIR one.Fil: Ezquer, Rodolfo Gerardo. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionósfera; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Cabrera, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mosert, Marta Estela. Gasur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Radicella, Sandro María. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionósfera; Argentina. Abdus Salam International Center for Theoretical Physics; ItaliaFil: Migoya Orue, Yenca Olivia. Gasur; Argentina. Universidad Tecnológica Nacional; Argentin

NeQuick 2 total electron content predictions for middle latitudes of North American region during a deep solar minimum

The performance of NeQuick 2 model in computing the vertical total electron content (VTEC) over a wide region placed at middle latitudes of North America during the deep solar minimum that occurred in 2008 has been checked. The long term relationship between EUV irradiance and F10.7 solar flux has changed markedly during the cycle 23/24 minimum with EUV levels decreasing more than expected from F10.7 proxy. A decrease of ionization in the ionosphere could have occurred. Thus, it could be expected that the models overestimate the value of ionospheric parameters for that deep solar minimum. For this study a high density VTEC data grid that covers the Continental United States (CONUS) has been compared with monthly median maps constructed with NeQuick 2. The results show that NeQuick 2 generally gives good predictions for the region which lies between 35°N to 50°N suggesting that nothing exceptional was happening during the 2008 minimum in terms of VTEC NeQuick 2's predictive capabilities. Taking into account that the modeled value is obtained by integration in height of the electron density profile, NeQuick2 would be assuming an inadequate profile for the few highest deviations observed, between 30°N and 35°N. Overall, the model does not give significant overestimation of VTEC as could be expected.Fil: Ezquer, Rodolfo Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionosfera; Argentina. Universidad Tecnológica Nacional. Centro de Investigación de Atmósfera Superior y Radiopropagación; ArgentinaFil: Scida, Luis Alberto. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionosfera; Argentina. Universidad Tecnológica Nacional. Centro de Investigación de Atmósfera Superior y Radiopropagación; ArgentinaFil: Migoya Orue, Yenca Olivia. The Abdus Salam International Centre for Theoretical Physics; ItaliaFil: Lescano, G. E.. Universidad Tecnológica Nacional. Centro de Investigación de Atmósfera Superior y Radiopropagación; ArgentinaFil: Alazo Cuartas, K.. The Abdus Salam International Centre for Theoretical Physics; ItaliaFil: Cabrera, M.A.. Universidad Tecnológica Nacional. Centro de Investigación de Atmósfera Superior y Radiopropagación; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Electricidad, Electrónica y Computación. Laboratorio de Telecomunicaciones; ArgentinaFil: Radicella, Sandro María. The Abdus Salam International Centre for Theoretical Physics; Itali

Day-to-day variability of ionospheric characteristics in the American sector

This paper presents an analysis of the variability of ionospheric characteristics (f o F2, M(3000)F2) measured at American latitudes (latitudinal range: -65.2, 18.5). The database includes ionograms recorded during different seasonal and solar activity conditions. The parameters used are: median, lower and upper quartiles. Two parameters are considered: Cup = upper quartile/median, and Clo = lower quartile/median. The diurnal, seasonal and latitudinal behaviour of the variability is analysed for low and high solar activity. The variability parameters for four typical time periods of the day (22-02LT; 05-07LT; 10-14LT; 18-20LT) are presented for different seasons and the two levels of solar activity. The results indicate that the variability of f o F2 is high in low solar activity and larger at night than during the day. Most of the considered cases have shown that the variability of f o F2 has a latitudinal dependence. For some cases the variability was maximum at modip ≇±30. The fact that the quartiles are not equidistant from the median value suggests that it would be convenient to develop a model on Cup and Clo in order to predict the variability range of f o F2. Moreover, low variability was observed for M(3000)F2 and it does not vary with modip.Fil: Ezquer, Rodolfo Gerardo. Universidad Nacional de Tucumán; Argentina. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mosert, Marta Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Corbella, Roberto Daniel. Universidad Tecnológica Nacional; ArgentinaFil: Erazú, Maximiliano Bautista. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Radicella, Sandro María. The Abdus Salam; ItaliaFil: Cabrera, Miguel Angel. Universidad Tecnológica Nacional; Argentina. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de la Zerda, Luis Ricardo. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin