Radio Techniques for Probing the Terrestrial Ionosphere

Hunsucker, R. D.

doi:10.1007/978-3-642-76257-4

Cited by 107 publications

(52 citation statements)

References 241 publications

(315 reference statements)

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“…However, for geometrical reasons power is usually expected to decrease with increasing slant range, d (e.g. Hunsucker, 1991). Thus, the near-range increase in power is contrary to expectations, and we identify the range of the SNR maximum as the limit of the HAIR region, d HAIR .…”

Section: Observations and Discussionmentioning

confidence: 58%

HF radar observations of high-aspect angle backscatter from the E-region

et al. 2004

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Abstract. We present evidence for the observation of highaspect angle HF radar backscatter from the auroral electrojets, and describe the spectral characteristics of these echoes. Such backscatter is observed at very near ranges where ionospheric refraction is not sufficient to bring the sounding radio waves to orthogonality with the magnetic field; the frequency dependence of this propagation effect is investigated with the Stereo upgrade of the CUTLASS Iceland radar. We term the occurrence of such echoes the "high-aspect angle irregularity region" or HAIR. It is suggested that backscatter is observed at aspect angles as high as 30 • , with an aspect sensitivity as low as 1 dB deg −1 . These echoes are distinguished from normal electrojet backscatter by having low Doppler shifts with an azimuthal dependence that appears more consistent with the direction of the convection electric field E than with the expected electron E×B drift direction. This is discussed in terms of the linear theory dispersion relation for electrojet waves.

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Section: Observations and Discussionmentioning

confidence: 58%

HF radar observations of high-aspect angle backscatter from the E-region

et al. 2004

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“…P 0 depends on the direction of the antenna relative to the stars and it changes in a cyclic manner due to the rotation of the Earth (with a period corresponding to the sidereal day). It should also be noted that this operating frequency, 30 MHz, has been found to be the best compromise between the ionospheric layer critical frequency and the ability to avoid interference from the crowded short-wave bands (Hunsucker, 1991). The occurrence rate of different absorption levels is presented in Fig.…”

Section: Riometer Datamentioning

confidence: 97%

Are variations in PMSE intensity affected by energetic particle precipitation?

2002

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Abstract.The correlation between variations in Polar Mesosphere Summer Echoes (PMSE) and variations in energetic particle precipitation is examined. PMSE were observed by the Esrange VHF MST Radar (ESRAD) at 67 • 53 N, 21 • 06 E. The 30 MHz riometer in Abisko (68 • 24 N, 18 • 54 E) registered radio wave absorption caused by ionization changes in response to energetic particle precipitation. The relationship between the linear PMSE intensity and the square of absorption has been estimated using the Pearson linear correlation and the Spearman rank correlation. The mean diurnal variation of the square of absorption and the linear PMSE intensity are highly correlated. However, their day-to-day variations show significant correlation only during the late evening hours. The correlation in late evening does not exceed 0.6. This indicates that varying ionization cannot be considered as a primary source of varying PMSE, and the high correlation found when mean diurnal variations are compared is likely a by-product of daily variations caused by other factors.

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“…Incoherent radars include the Jicamarca Radio Observatory located along the geomagnetic equator in Lima, Peru, (49.92 MHz), the Arecibo dish in Puerto Rico (430 MHz), and European Incoherent Scatter, northern Scandinavia, operating at UHF (931 and 500 MHz) and VHF (224 MHz) (Zolesi & Cander 2014). To access information about the topside ionosphere, satellite-based topside sounders have also been used (Hunsucker 2013). With the advent of radio communication satellites, the signals from such satellite systems were used to obtain spatial and temporal information on the ionosphere (Leitinger et al 1984).…”

Section: Introductionmentioning

confidence: 99%

Ionospheric Modelling using GPS to Calibrate the MWA. I: Comparison of First Order Ionospheric Effects between GPS Models and MWA Observations

Arora

Morgan

Ord

et al. 2015

Publ. Astron. Soc. Aust.

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We compare first-order (refractive) ionospheric effects seen by the MWA with the ionosphere as inferred from GPS data. The first-order ionosphere manifests itself as a bulk position shift of the observed sources across an MWA field of view. These effects can be computed from global ionosphere maps provided by GPS analysis centres, namely the CODE. However, for precision radio astronomy applications, data from local GPS networks needs to be incorporated into ionospheric modelling. For GPS observations, the ionospheric parameters are biased by GPS receiver instrument delays, among other effects, also known as receiver DCBs. The receiver DCBs need to be estimated for any non-CODE GPS station used for ionosphere modelling. In this work, single GPS station-based ionospheric modelling is performed at a time resolution of 10 min. Also the receiver DCBs are estimated for selected Geoscience Australia GPS receivers, located at Murchison Radio Observatory, Yarragadee, Mount Magnet and Wiluna. The ionospheric gradients estimated from GPS are compared with that inferred from MWA. The ionospheric gradients at all the GPS stations show a correlation with the gradients observed with the MWA. The ionosphere estimates obtained using GPS measurements show promise in terms of providing calibration information for the MWA.

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Radio Techniques for Probing the Terrestrial Ionosphere

Cited by 107 publications

References 241 publications

HF radar observations of high-aspect angle backscatter from the E-region

HF radar observations of high-aspect angle backscatter from the E-region

Are variations in PMSE intensity affected by energetic particle precipitation?

Ionospheric Modelling using GPS to Calibrate the MWA. I: Comparison of First Order Ionospheric Effects between GPS Models and MWA Observations

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