Zonal wind velocity profiles in the equatorial electrojet derived from phase velocities of type II radar echoes

Shume, E. B.; Hysell, D. L.; Chau, Jorge L.

doi:10.1029/2005ja011210

Cited by 20 publications

(30 citation statements)

References 29 publications

(51 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While neutral wind signatures are likely present in the oblique echo data, it is not obvious how to isolate them. Figure 7 shows zonal neutral wind estimates inferred using just the method of Shume et al (2005a). The winds are periodic in altitude and propagate slowly downward with amplitudes of about 60 m/s and a period that is approximately diurnal.…”

Section: Neutral Windsmentioning

confidence: 99%

“…One is a new technique for estimating Eregion electron density profiles from the Faraday rotation of the coherent scatter (Hysell and Chau, 2001;Shume et al, 2005b). Another is a new ability to infer zonal winds in the electrojet region from coherent scatter using a model-based inversion (Shume et al, 2005a). A third development is radar imaging, which reveals in detail the dispersion characteristics of large-scale electrojet waves (Hysell and Chau, 2006).…”

Section: Whereas Farley Buneman Instabilities Can Generate Irregu-mentioning

confidence: 99%

“…4. Shume et al (2005a) presented a model-based inversion technique for inferring zonal neutral wind profiles in the electrojet from the Doppler shifts of oblique type 2 echoes. The method assumes that the Doppler shifts obey the linear dispersion relation (1).…”

Section: Neutral Windsmentioning

confidence: 99%

See 2 more Smart Citations

Combined radar observations of equatorial electrojet irregularities at Jicamarca

et al. 2007

Self Cite

View full text Add to dashboard Cite

Abstract. Daytime equatorial electrojet plasma irregularities were investigated using five distinct radar diagnostics at Jicamarca including range-time-intensity (RTI) mapping, Faraday rotation, radar imaging, oblique scattering, and multiplefrequency scattering using the new AMISR prototype UHF radar. Data suggest the existence of plasma density striations separated by 3-5 km and propagating slowly downward. The striations may be caused by neutral atmospheric turbulence, and a possible scenario for their formation is discussed. The Doppler shifts of type 1 echoes observed at VHF and UHF frequencies are compared and interpreted in light of a model of Farley Buneman waves based on kinetic ions and fluid electrons with thermal effects included. Finally, the up-down and east-west asymmetries evident in the radar observations are described and quantified.

show abstract

Section: Neutral Windsmentioning

confidence: 99%

Section: Whereas Farley Buneman Instabilities Can Generate Irregu-mentioning

confidence: 99%

See 1 more Smart Citation

Combined radar observations of equatorial electrojet irregularities at Jicamarca

et al. 2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…The termsˆ ,D, andˆ represent the conductivity, diffusion, and gravity tensors, respectively (see, e.g., Shume et al, 2005 for an explicit definition of those terms). The variables U and B are the neutral wind speed and magnetic field, respectively.…”

Section: Sami3/esf Modelmentioning

confidence: 99%

Equatorial spread F studies using SAMI3 with two-dimensional and three-dimensional electrostatics

Aveiro

Huba

2013

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. This letter presents a study of equatorial F region irregularities using the NRL SAMI3/ESF model, comparing results using a two-dimensional (2-D) and a threedimensional (3-D) electrostatic potential solution. For the 3-D potential solution, two cases are considered for parallel plasma transport: (1) transport based on the parallel ambipolar field, and (2) transport based on the parallel electric field. The results show that the growth rate of the generalized Rayleigh-Taylor instability is not affected by the choice of the potential solution. However, differences are observed in the structures of the irregularities between the 2-D and 3-D solutions. Additionally, the plasma velocity along the geomagnetic field computed using the full 3-D solution shows complex structures that are not captured by the simplified model. This points out that only the full 3-D model is able to fully capture the complex physics of the equatorial F region.

show abstract

“…These limitations include Faraday rotation measurements using the plasma waves as scatterers on an oblique path (Hysell and Chau, 2002;Shume et al, 2005b); an improved ability to image plasma structures in the unstable region with interferometric methods (Hysell and Chau, 2006); an inversion technique to deduce neutral winds from the Doppler shift of oblique plasma waves (Shume et al, 2005a); identification of the Doppler shift of "150 km echoes" with E×B drifts due to the zonal electric field (Kudeki and Fawcett, 1993); and establishment of a new AMISR prototype radar at 430 MHz at Jicamarca (Cuevas et al, 2007 1 ). Hysell et al (2007) re-ported the first combined results using these systems.…”

Section: Introductionmentioning

confidence: 99%

Eddy turbulence parameters inferred from radar observations at Jicamarca

2007

Self Cite

View full text Add to dashboard Cite

Abstract. Significant electron density striations, neutral temperatures 27 K above nominal, and intense wind shear were observed in the E-region ionosphere over the Jicamarca Radio Observatory during an unusual event on 26 July 2005 (Hysell et al., 2007). In this paper, these results are used to estimate eddy turbulence parameters and their effects. Models for the thermal balance in the mesosphere/lower thermosphere and the charged particle density in the E region are developed here. The thermal balance model includes eddy conduction and viscous dissipation of turbulent energy as well as cooling by infrared radiation. The production and recombination of ions and electrons in the E region, together with the production and transport of nitric oxide, are included in the plasma density model. Good agreement between the model results and the experimental data is obtained for an eddy diffusion coefficient of about 1×10 3 m 2 /s at its peak, which occurs at an altitude of 107 km. This eddy turbulence results in a local maximum of the temperature in the upper mesosphere/lower thermosphere and could correspond either to an unusually high mesopause or to a double mesosphere. Although complicated by plasma dynamic effects and ongoing controversy, our interpretation of Farley-Buneman wave phase velocity (Hysell et al., 2007) is consistent with a low Brunt-Väisälä frequency in the region of interest. Nitric oxide transport due to eddy diffusion from the lower thermosphere to the mesosphere causes electron density changes in the E region whereas NO density modulation due to irregularities in the eddy diffusion coefficient creates variability in the electron density.

show abstract

Zonal wind velocity profiles in the equatorial electrojet derived from phase velocities of type II radar echoes

Cited by 20 publications

References 29 publications

Combined radar observations of equatorial electrojet irregularities at Jicamarca

Combined radar observations of equatorial electrojet irregularities at Jicamarca

Equatorial spread F studies using SAMI3 with two-dimensional and three-dimensional electrostatics

Eddy turbulence parameters inferred from radar observations at Jicamarca

Contact Info

Product

Resources

About