New ionospheric and magnetospheric specification models

Tascione, Thomas F.; Kroehl, H. W.; Creiger, Roderick; Freeman, J. W.; Wolf, R. A.; Spiro, R. W.; Hilmer, R. V.; Shade, J.W.; Hausman, B. A.

doi:10.1029/rs023i003p00211

Cited by 51 publications

(24 citation statements)

References 34 publications

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“…Because we want to know the true TEC, we used a three-dimensional ray-tracing code called TRACKER [Argo et al, 1992], which uses the Appleton-Hartree form for the dispersion relation. TRACKER incorporates the ionospheric conductivity and electron density (ICED) model [Tascione et al, 1988]. We use TRACKER by specifying the transmitter location and receiver (FORTE) location and the date and time of the event.…”

Section: Effects Of Higher-order Termsmentioning

confidence: 99%

Measurements of transionospheric radio propagation parameters using the FORTE satellite

Massey¹,

Knox²,

Franz

et al. 1998

Radio Science

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Abstract. We report initial measurements of ionospheric propagation parameters, particularly the total electron content (TEC), using the recently launched FORTE satellite. FORTE, which orbits the Earth at an altitude of 800 km and an inclination of 70 ø, contains a set of wideband radio receivers whose output is digitally recorded. A specialized triggering circuit identifies transient, broadband radio events, which include radiation from lightning, transionospheric pulse pairs, and man-made sources. Event data are transmitted to the ground station for analysis. In this paper we examine signals transmitted from an electromagnetic pulse generator operated at Los Alamos. The transmitter produces nearly impulsive signals in the VHF range. The received signal is dispersed by the ionosphere, and the received signal can be analyzed to deduce the total electron content along the path. By comparing the slant TEC thus measured with results from a ray-tracing code, we can deduce the vertical TEC to 800 km. Data from eight passes are presented. These types of data (in larger quantities) are of interest to operators of radar altimeters, who need data to corroborate their corrections for the ionospheric TEC. The combination of FORTE TEC data to 800 km and TEC measurements to 20,000 km (the Global Positioning System orbital altitude) can provide useful information for assessing the validity of models of plasmaspheric electron density. Initial estimates of the plasmaspheric density, on two daytime passes, are about 6 TECU. The signal received by FORTE, which is linearly polarized at the transmitter, is split into two magnetoionic modes by the ionosphere. The receiving antenna is also linearly polarized and therefore receives both modes. By measuring the beat frequency between the two modes, we can deduce the product of the geomagnetic field and the cosine of the angle between the field and the propagation vector. The possibility of using the measured slant TEC and the beat frequency to geolocate impulsive signals is discussed. IntroductionOn August 29, 1997, a space vehicle named FORTE was placed into a circular orbit with an altitude of 800 km and an inclination of 70 ø by a Pegasus launch vehicle. FORTE is an acronym for fast onboard recording of transient events, and the satellite includes two major payloads. The primary payload is a set of tunable wideband radio receivers followed by fast digitizers. The secondary payload, comprising an imaging camera and a fast photodiode detector, will not be discussed in this paper. One of the purposes for the radio payload is to provide data use this information will be described below. The received signal can also be analyzed, under some circumstances, to infer the product of the geomagnetic field and the cosine of the angle between the field and the propagation vector. This information can be used to further constrain the locus of possible source locations.In the sections to follow we will discuss the theoretical basis of the measurements and data analysis and then describe the transm...

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Section: Effects Of Higher-order Termsmentioning

confidence: 99%

Measurements of transionospheric radio propagation parameters using the FORTE satellite

Massey¹,

Knox²,

Franz

et al. 1998

Radio Science

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“…The majority of the models may be categorized into three groups: (i) empirical models (Bent et al 1972;Ching & Chiu 1973;Rawer et al 1978;Anderson et al 1987Anderson et al , 1989Nisbet & Divany 1987;Tascione et al 1988;Daniell et al 1995;Batista et al 1996;Abdu et al 2008;Brum et al 2011Brum et al , 2012Bilitza et al 2012), (ii) theoretical or mathematical models (Bailey et al 1978;Anderson & Klobuchar 1983;Anderson et al 1996;Schunk & Sojka 1996;Brum et al 2006), and (iii) parameterized models (Daniell et al 1995;Souza et al 2010). The empirical models are based on statistical analyses of long-term ionospheric measurements, while theoretical/mathematical models are developed by solving a set of equations accounting for different physical and chemical processes that take place in the ionosphere.…”

Section: Introductionmentioning

confidence: 99%

An empirical model of ionospheric total electron content (TEC) near the crest of the equatorial ionization anomaly (EIA)

Hajra

Chakraborty²,

Tsurutani

et al. 2016

J. Space Weather Space Clim.

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We present a geomagnetic quiet time (Dst > À50 nT) empirical model of ionospheric total electron content (TEC) for the northern equatorial ionization anomaly (EIA) crest over Calcutta, India. The model is based on the 1980-1990 TEC measurements from the geostationary Engineering Test Satellite-2 (ETS-2) at the Haringhata (University of Calcutta, India: 22.58°N, 88.38°E geographic; 12.09°N, 160.46°E geomagnetic) ionospheric field station using the technique of Faraday rotation of plane polarized VHF (136.11 MHz) signals. The ground station is situated virtually underneath the northern EIA crest. The monthly mean TEC increases linearly with F 10.7 solar ionizing flux, with a significantly high correlation coefficient (r = 0.89-0.99) between the two. For the same solar flux level, the TEC values are found to be significantly different between the descending and ascending phases of the solar cycle. This ionospheric hysteresis effect depends on the local time as well as on the solar flux level. On an annual scale, TEC exhibits semiannual variations with maximum TEC values occurring during the two equinoxes and minimum at summer solstice. The semiannual variation is strongest during local noon with a summer-to-equinox variability of 50-100 TEC units. The diurnal pattern of TEC is characterized by a pre-sunrise (0400-0500 LT) minimum and near-noon (1300-1400 LT) maximum. Equatorial electrodynamics is dominated by the equatorial electrojet which in turn controls the daytime TEC variation and its maximum. We combine these long-term analyses to develop an empirical model of monthly mean TEC. The model is validated using both ETS-2 measurements and recent GNSS measurements. It is found that the present model efficiently estimates the TEC values within a 1-r range from the observed mean values.

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“…2.3.3 the concept of electron density profile, or in another definition, electron concentration versus altitude was introduced considering its importance for both theoretical studies and practical applications. (Tascione et al 1988) Controlled by the sunspot number (SSN) and geomagnetic Q index and conceived to allow for real-time updates of the input parameters from a number of sensors Global, improved performance for high-latitude PIM (Daniell et al 1995) Amalgam of a number of other models and uses either the foF2 CCIR coefficients for normalisation of the electron density profiles or coefficients produced by the TDIM Many other models have been developed in recent years, including those in Sects. 5.3 and 5.5 like the SLIM, FAIM, and more recently the PRISM (Parameterised Real-Time Ionospheric Specification Model), capable of producing critical frequencies and peak heights for the ionospheric E and F2 layers, as well as electron density profiles from 90 to 1,600 km and TEC.…”

Section: Models Of the Electron Density Profile In The Ionospherementioning

confidence: 99%

Ionospheric Models for Prediction and Forecasting

Zolesi

Cander

2013

Ionospheric Prediction and Forecasting

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A comprehensive knowledge of the Earth's ionospheric structure and dynamics, in particular its refractivity profiles, is necessary to guarantee the effective operation, planning, and management of numerous radio communication and navigation systems. These can be based either on: (1) advanced models coupled across the space-terrestrial environment, providing detailed knowledge of conditions and good predictions; or (2) specific well-targeted services that provide products like specification data, post-event analysis, long-term predictions, instantaneous nowcasting and short-term forecasting generated in real or near real-time in response to available observations. Since its discovery, many models of the Earth's ionosphere have been developed. These fall into several classes and include the D, E, and F regions at low, middle, and high-latitudes. Ionospheric models can be divided into three main groups:1. theoretical, parameterised, and empirical models that define not only the ionospheric electron density profile but also the different profile parameters in terms of ionospheric characteristics at every point on the globe, for example foE, foF1, and linear or polynomial foF2 versus R 12 ; 2. assimilation models for a full 3-D electron density profile; 3. empirical and physical models or methods for 2-D global, regional, and local mapping of the characteristic ionospheric parameters both for long-term prediction and nowcasting in the field of radio propagation and navigation (e.g. CCIR and URSI maps of ITU-R, ionospheric COST actions maps, etc.).The first two groups of models are more general and are therefore presented in this Chapter, while the third group of models and methods are more practical and are described in the following Chap. 6.

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New ionospheric and magnetospheric specification models

Cited by 51 publications

References 34 publications

Measurements of transionospheric radio propagation parameters using the FORTE satellite

Measurements of transionospheric radio propagation parameters using the FORTE satellite

An empirical model of ionospheric total electron content (TEC) near the crest of the equatorial ionization anomaly (EIA)

Ionospheric Models for Prediction and Forecasting

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