High-resolution coherent backscatter interferometric radar images of equatorial spread F using Capon's method

Rodrigues, F. S.; Paula, E. R. de; Zewdie, Gebreab K.

doi:10.5194/angeo-35-393-2017

Cited by 6 publications

(2 citation statements)

References 33 publications

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“…In addition, we propose the use of the following radar techniques among others in the investigation of the dynamics of irregularities in the African equatorial ionosphere, which includes oblique scattering, range-time-intensity (RTI) mapping, Faraday rotation, radar imaging techniques and multiple frequency scattering (Basu et al, 1978;Kudeki et al, 1981;Kudeki and Sürücü, 1991;Hysell and Woodman, 1997;Hysell and Chau, 2001;Hysell and Chau, 2006;Harding and Milla, 2013;Rodrigues et al, 2017). Table 2 shows the proposed scientific objectives and the proposed radar parameters (data products) to investigate the scientific questions.…”

Section: Instrumentationmentioning

confidence: 99%

Understanding the global dynamics of the equatorial ionosphere in Africa for space weather capabilities: A science case for AfrequaMARN

Lawal

Lester

Cowley

et al. 2019

Journal of Atmospheric and Solar-Terrestrial Physics

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The equatorial region of the Earth's ionosphere is one of the most complex ionospheric regions due to its interactions, instabilities, and several unresolved questions regarding its dynamics, electrodynamics, and physical processes. The equatorial ionosphere overall spans three continents with the longest region being that over the African continent. Satellite observations have demonstrated that very large differences exist in the formation of ionospheric irregularities over the African sector compared with other longitudinal sectors. This may be a consequence of the symmetric shape of the magnetic equator over the continent and the lack of variability in latitude. In this paper, we propose a science campaign to equip the African sector of the magnetic equator with ground-based instruments, specifically magnetometers and radars. The network of radars proposed is similar in style and technique to the high-latitude SuperDARN radar network, while the magnetometers will form an array along the equatorial belt. These two proposed space physics instruments will be used to study this region of the equatorial ionosphere over a long interval of time, at least one solar cycle. The deployment of an array of magnetometers (AfrequaMA) and a radar network (AfrequaRN) in the African sector of the magnetic equator is jointly called the Africa Equatorial Magnetometer Array and Radar Network (AfrequaMARN), which will provide simultaneous observations of both electric and magnetic variations over the African sector. We also examine the possible science questions such a magnetometer array and radar network would be able to address, both individually and in conjunction with other space-based and ground-based instrumentation. The proposed projects will clearly improve our understanding of the dynamics of the equatorial ionosphere and our understanding of its role in balancing the large-scale ionospheric current system, and will contribute to our ability to adequately model ionospheric and plasmaspheric densities. It will also enhance our understanding of global ionospheric processes, which will improve the space weather capabilities of the African and international space science communities.

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Section: Instrumentationmentioning

confidence: 99%

Understanding the global dynamics of the equatorial ionosphere in Africa for space weather capabilities: A science case for AfrequaMARN

Lawal

Lester

Cowley

et al. 2019

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Observations made with multiple antenna baselines and interferometric techniques can provide high resolution (in time and space) information about the two‐dimensional (height versus zonal distance) distribution of irregularities within the radar field‐of‐view (e.g. Hysell & Chau, ; Harding & Milla , ; Rodrigues et al, ).…”

Section: Introductionmentioning

confidence: 99%

MELISSA: System description and spectral features of pre‐ and post‐midnight F‐region echoes

et al. 2019

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Most of the low-latitude ionospheric radar observations in South America come from the Jicamarca Radio Observatory, located in the western longitude sector (∼ 75 • W). The deployment of the 30 MHz FAPESP-Clemson-INPE (FCI) coherent backscatter radar in the magnetic equatorial site of São Luis, Brazil, in 2001 allowed observations to be made in the eastern sector (∼ 45 • W). However, despite being operational for several years (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012), FCI only made observations during daytime and pre-midnight hours, with a few exceptions. Here, we describe an upgraded system that replaced the FCI radar and present results of full-night F-region observations. This radar is referred to as Measurements of Equatorial and Low-latitude Ionospheric irregularities over São Luís, South America (MELISSA), and made observations between March 2014 and December 2018. We present results of our analyses of pre-and post-midnight F-region echoes with focus on the spectral features of post-midnight echoes and how they compare to spectra of echoes observed in the post-sunset sector. The radar observations indicate that post-midnight F-region irregularities were generated locally and were not a result of "fossil" structures generated much earlier in time (in other longitude sectors) and that drifted into the radar field-of-view. This also includes cases where the echoes are weak and that would be associated with decaying equatorial spread F (ESF) structures. Collocated digisonde observations show modest but noticeable F-region apparent uplifts prior to post-midnight ESF events. We associate the equatorial uplifts with disturbed dynamo effects and with destabilizing F-region conditions leading to ESF development.

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Radio-frequency imaging techniques for ionospheric, magnetospheric, and planetary studies

Fung

Benson

Galkin

et al. 2022

Magnetospheric Imaging

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High-resolution coherent backscatter interferometric radar images of equatorial spread F using Capon's method

Cited by 6 publications

References 33 publications

Understanding the global dynamics of the equatorial ionosphere in Africa for space weather capabilities: A science case for AfrequaMARN

Understanding the global dynamics of the equatorial ionosphere in Africa for space weather capabilities: A science case for AfrequaMARN

MELISSA: System description and spectral features of pre‐ and post‐midnight F‐region echoes

Radio-frequency imaging techniques for ionospheric, magnetospheric, and planetary studies

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