The 30‐MHz radar interferometer studies of midlatitude <i>E</i> region irregularities

Hysell, D. L.; Burcham, Joel D.

doi:10.1029/1999ja000411

Cited by 71 publications

(100 citation statements)

References 43 publications

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“…3 shows, there are multiple echo traces which comprise QP echoes with up to four striations being visible at the same time (around 18:27 LT). There are reports on the simultaneous presence of multiple of QP echoes with up to 8 to 9 striations Hysell and Burcham, 2000). From our observations it is apparent that the echo patches inside the striations were varying with time and have negative slope, which means that they propagated towards the radar.…”

Section: Resultsmentioning

confidence: 53%

“…Since Farley et al (1981) introduced this technique for the study of equatorial electrojet irregularities with the Jicamarca radar, it has been implemented at various VHF radars, such as the MU radar , the Chung-Li VHF radar (Pan et al, 1994), for instance. The multiple baseline interferometer technique helps to reveal the spatial and temporal characteristics of the scatterers, thereby imaging the motion/tracking of scatterers in the three-dimensional plane (Hysell and Burcham, 2000;Yamamoto et al, 1994;Wang and Chu, 2001). We apply this technique in this paper, as well, and can show that the additional information on the height of the scattering irregularities, creating the LQP echoes, can only be obtained by this more elaborate technique and yields further information about the larger scale behavior of these irregularities.…”

Section: Introductionmentioning

confidence: 94%

“…QP echoes are observed simply to be due to sequential unstable plasma patches or blobs which traverse across the radar field-of-view, sometimes in a wave-like fashion. Also, the three-dimensional observations on 30 MHz (Hysell and Burcham, 2000) show that the QP echoes can be recognized as quasi-point target scatterers drifting through the radar beam at approximately constant altitude.…”

Section: Introductionmentioning

confidence: 99%

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Three-dimensional tracking of mid-latitude quasi-periodic E-region echoes observed with the Chung-Li VHF radar

Chen

Röttger

et al. 2005

Ann. Geophys.

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Abstract. This paper presents observations of low-altitude mid-latitude E-region irregularities obtained with the 52-MHz Chung-Li VHF radar. These are carried out in the interferometer mode to investigate the behavior of these irregularities over time and space. The observations presented here show the characteristics of type-II echoes noted by a negative slope, i.e. they are approaching the radar as a function of time. The range-time-intensity (RTI) plots obtained through power spectrum analysis reveal the quasi-periodic striations, which are known as LQP (Low-altitude QP) echoes. Our interferometer analysis allows one to investigate the motion (i.e. "tracking") of the LQP echo patches in three dimensions. This method is superior to just evaluating the variations of the echo power as a function of range and time in the standard RTI-plots. By applying this method, we show that the echo patches in different striations remain at almost the same altitude when we trace the isolated echoing regions until they disappear from the radar view. We further compare the rate of change of the range (range rate dR/dt) by two techniques: one by simply measuring the varying slope of the LQP echoes from RTI plot, the other by tracking the threedimensional locations of the LQP scatterers by using the interferometer technique. We finally prove that the changes in range as a function of time, deduced from the interferometer technique, are significantly correlated with those of the standard range rate analysis. However, the standard range rate analysis does not provide information about the correct location and the variation of the LQP irregularities. The threedimensional analysis, which we introduced for tracking individual striations, shows that LQP echo patches are confined to between 98 and 100 km altitude. This suggests that the irregularities which cause the LQP echoes drifted through the radar beam at approximately constant altitude, which we tend to attribute to a region of large-scale vertical shear of the horizontal wind.

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Section: Resultsmentioning

confidence: 53%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Three-dimensional tracking of mid-latitude quasi-periodic E-region echoes observed with the Chung-Li VHF radar

Chen

Röttger

et al. 2005

Ann. Geophys.

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“…4. Hysell and Burcham (2000); Hysell et al (2002);720 Y. S. Dimant and M. M. Oppenheim: Plasma cloud in ionosphere: effect of external field Yokoyama et al (2004) performed 2-D and 3-D numerical simulations of cloud polarization, current closure, and E-F region coupling, including the recently predicted sporadic-E instability Tsunoda, 2002b, 2004;Tsunoda et al, 2004;Tsunoda, 2006). These simulations give spatial distributions of the electric field but, being performed for particular cases only, provide no parameter dependencies as we will provide.…”

Section: Introductionmentioning

confidence: 99%

Interaction of plasma cloud with external electric field in lower ionosphere

Dimant

Oppenheim

2010

Ann. Geophys.

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Abstract. In the auroral lower-E and upper-D region of the ionosphere, plasma clouds, such as sporadic-E layers and meteor plasma trails, occur daily. Large-scale electric fields, created by the magnetospheric dynamo, will polarize these highly conducting clouds, redistributing the electrostatic potential and generating anisotropic currents both within and around the cloud. Using a simplified model of the cloud and the background ionosphere, we develop the first selfconsistent three-dimensional analytical theory of these phenomena. For dense clouds, this theory predicts highly amplified electric fields around the cloud, along with strong currents collected from the ionosphere and circulated through the cloud. This has implications for the generation of plasma instabilities, electron heating, and global MHD modeling of magnetosphere-ionosphere coupling via modifications of conductances induced by sporadic-E clouds.

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“…The radar imaging technique is now widely used for studying fine structures of ionospheric irregularities from equatorial to high latitudes (Hysell, 1996;Hysell and Burcham, 2000;Hysell and Chau, 2002;Hysell et al, , 2004Bahcivan et al, 2005;Saito et al, 2006Saito et al, , 2007. With this technique, structures smaller than the radar beam width can be resolved.…”

Section: Introductionmentioning

confidence: 99%

Imaging observations of nighttime mid-latitude F-region field-aligned irregularities by an MU radar ultra-multi-channel system

2008

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Abstract. Mid-latitude F-region field-aligned irregularities (FAIs) were studied by using the middle-and-upper atmosphere (MU) radar ultra-multi-channel system with the radar imaging technique. On 12 June 2006, F-region FAI echoes with a period of about one hour were observed intermittently. These echoes were found to be embedded in mediumscale traveling ionospheric disturbances (MSTIDs) observed as variations of total electron content (TEC). The echoes drifting away from (toward) the radar were observed in the depletion (enhancement) phase of the MSTID. The Doppler velocity of the echoes is consistent with the range rates in the the range-time-intensity (RTI) maps. Fine scale structures with a spatial scale of 10 km or less were found by the radar imaging analysis. Those structures with positive Doppler velocities (moving away from the radar) appeared to drift north-(up-) westward, and those with negative Doppler velocities south-(down-) eastward approximately along the wavefronts of the MSTID. FAIs with positive Doppler velocities filling TEC depletion regions were observed.

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The 30‐MHz radar interferometer studies of midlatitude E region irregularities

Abstract: Abstract.The 30

Cited by 71 publications

References 43 publications

Three-dimensional tracking of mid-latitude quasi-periodic E-region echoes observed with the Chung-Li VHF radar

Three-dimensional tracking of mid-latitude quasi-periodic E-region echoes observed with the Chung-Li VHF radar

Interaction of plasma cloud with external electric field in lower ionosphere

Imaging observations of nighttime mid-latitude F-region field-aligned irregularities by an MU radar ultra-multi-channel system

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