VHF radar signals scattered from the equatorial mesosphere

Røyrvik, O.

doi:10.1029/rs018i006p01325

Cited by 23 publications

(20 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Negative correlations were reported for the lower mesosphere, suggestive of an increasing role for reflections at heights closer to the stratosphere, or the possibility of inertial range turbulence as suggested by Røyrvik (1985). Subsequent Jicamarca measurements conducted with a 2 km resolution (Røyrvik, 1983) showed similar and consistent results, including predominantly "aspect sensitive" returns from below 75 km.…”

Section: Introductionsupporting

confidence: 62%

“…This is in contrast to earlier studies of Fukao et al (1980) and Røyrvik (1983) conducted with vertical beams. These earlier studies showed a significant amount of negative correlations in the lower mesosphere below 75 km.…”

Section: Vertical Beam Data and Aspect Sensitivitycontrasting

confidence: 54%

“…These earlier studies showed a significant amount of negative correlations in the lower mesosphere below 75 km. The oblique beam data from May 2003 examined here do not show as strong an evidence of separate altitude regimes for positive and negative correlation, but the data from July 2004, which included vertical beam observations, show an abundance of thin sheets from primarily below 70 km with associated negative correlations in agreement with Fukao et al (1980) and Røyrvik (1983).…”

Section: Vertical Beam Data and Aspect Sensitivitysupporting

confidence: 53%

“…The early MST experiments of Fukao et al (1980) and Røyrvik (1983) lacked the height resolution required to observe the peculiar characteristics of layer boundaries predicted by Bolgiano (1968) and, in general, to distinguish between specular reflections and anisotropic turbulence; the radar volumes often contained a multitude of density structures, potentially associated with different echoing mechanisms.…”

Section: Introductionmentioning

confidence: 99%

“…The study is essentially an update of the earlier work of Fukao et al (1980) and Røyrvik (1983) carried out with a nominal height resolution of 150 m -a standard for state-of-the-art MST radars -and aims a better understanding of mesospheric density structures and related radar scatter at low-latitudes. It is in fact the first correlation study conducted at Jicamarca that "resolves" the echoing layers with many independent range gates.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A high-resolution study of mesospheric fine structure with the Jicamarca MST radar

et al. 2006

View full text Add to dashboard Cite

Abstract. Correlation studies performed on data from recent mesospheric experiments conducted with the 50-MHz Jicamarca radar in May 2003 and July 2004 are reported. The study is based on signals detected from a combination of vertical and off-vertical beams. The nominal height resolution was 150 m and spectral estimates were obtained after ∼1 min integration. Spectral widths and backscattered power generally show positive correlations at upper mesospheric heights in agreement with earlier findings (e.g., Fukao et al., 1980) that upper mesospheric echoes are dominated by isotropic Bragg scatter. In many instances in the upper mesosphere, a weakening of positive correlation away from layer centers (towards top and bottom boundaries) was observed with the aid of improved height resolution. This finding supports the idea that layer edges are dominated by anisotropic turbulence. The data also suggests that negative correlations observed at lower mesospheric heights are caused by scattering from anisotropic structures rather than reflections from sharp vertical gradients in electron density.

show abstract

Section: Introductionsupporting

confidence: 62%

Section: Vertical Beam Data and Aspect Sensitivitycontrasting

confidence: 54%

Section: Vertical Beam Data and Aspect Sensitivitysupporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A high-resolution study of mesospheric fine structure with the Jicamarca MST radar

et al. 2006

View full text Add to dashboard Cite

show abstract

On the governing dynamics of the VHF radar echoes from the mesosphere and collision‐dominated lower E region over Gadanki (13.5°N, 79.2°E)

et al. 2017

View full text Add to dashboard Cite

In the present communication, the role of neutral dynamical processes in governing the morphology and seasonal variations of daytime VHF radar echoes from the mesosphere and the collision‐dominated lower E region is discussed. While the seasonal variations of mesospheric echo occurrence show semiannual variation with their maxima in the equinoxes, the occurrence of E region echoes shows strong annual variation peaking in the summer with two secondary maxima identical to semiannual variation of the mesospheric echoes. The occurrence rates of the E region echoes, however, display year‐to‐year variability. Semiannual variations in the occurrence of low‐latitude mesospheric echoes are closely linked with similar variations in the occurrences of temperature inversion, large wind shear, tides, and gravity wave activities in the same height region. In the case of E region echoes, the summer maximum and equinoctial secondary maxima are found to be linked with similar variations in wind and wind shear, Es activity, tidal, and gravity wave activities. Further, the summer maximum is found to be strongly correlated with that of meteor flux and nonmigrating diurnal tide. This finding is significant given the fact that such wind field in the presence of metallic ions could form both Es and field‐aligned irregularities. The present results show that tides and gravity waves are the most important dynamical factors governing the morphology and seasonal variations of the mesospheric as well as lower E region echoes observed over Gadanki. These results are discussed in the light of current understanding on the dynamical coupling of the mesosphere and lower E region through tides and gravity waves.

show abstract

The form of metre-scale turbulence at mesopause heights in summer

Thomas

Astin

1994

Journal of Atmospheric and Terrestrial Physics

View full text Add to dashboard Cite

VHF radar signals scattered from the equatorial mesosphere

Cited by 23 publications

References 19 publications

A high-resolution study of mesospheric fine structure with the Jicamarca MST radar

A high-resolution study of mesospheric fine structure with the Jicamarca MST radar

On the governing dynamics of the VHF radar echoes from the mesosphere and collision‐dominated lower E region over Gadanki (13.5°N, 79.2°E)

The form of metre-scale turbulence at mesopause heights in summer

Contact Info

Product

Resources

About