Statistical characteristics of PMWE observations by the EISCAT VHF radar

Strelnikova, Irina; Rapp, Markus

doi:10.5194/angeo-31-359-2013

Cited by 13 publications

(10 citation statements)

References 60 publications

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“…Vast efforts have been made to derive turbulence energy dissipation field in the MLT by means of radar soundings (e.g., Hocking, 1983Hocking, , 1985Hall et al, 1998Hall et al, , 2003Strelnikova and Rapp, 2013;Lübken, 2014). It is understood that the radar-based turbulence measurements can be biased by both instrumental effects as well as some GWs' contributions to the measured variances of the wind fluctuations.…”

Section: Discussionmentioning

confidence: 99%

“…To better compare the in situ and radar turbulence measurements, we plotted mean energy dissipation rates derived between 80 and 90 km heights from the rocket-borne and radar This indicates that the high ε values, derived from the EISCAT measurements in this study or, for example, by Strelnikova and Rapp (2013) are likely realistic. Another important remark regarding these measurements is that the mean ε values differ from high-resolution instantaneous measurements by orders of magnitude.…”

Section: Turbulence Measurementsmentioning

confidence: 99%

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Spatial and temporal variability in MLT turbulence inferred from in situ and ground-based observations during the WADIS-1 sounding rocket campaign

et al. 2017

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Abstract. In summer 2013 the WADIS-1 sounding rocket campaign was conducted at the Andøya Space Center (ACS) in northern Norway (69 • N, 16 • E). Among other things, it addressed the question of the variability in mesosphere/lower thermosphere (MLT) turbulence, both in time and space. A unique feature of the WADIS project was multi-point turbulence sounding applying different measurement techniques including rocket-borne ionization gauges, VHF MAARSY radar, and VHF EISCAT radar near Tromsø. This allowed for horizontal variability to be observed in the turbulence field in the MLT at scales from a few to 100 km. We found that the turbulence dissipation rate, ε varied in space in a wavelike manner both horizontally and in the vertical direction. This wavelike modulation reveals the same vertical wavelengths as those seen in gravity waves. We also found that the vertical mean value of radar observations of ε agrees reasonably with rocket-borne measurements. In this way defined ε radar value reveals clear tidal modulation and results in variation by up to 2 orders of magnitude with periods of 24 h. The ε radar value also shows 12 h and shorter (1 to a few hours) modulations resulting in one decade of variation in ε radar magnitude. The 24 h modulation appeared to be in phase with tidal change of horizontal wind observed by SAURA-MF radar. Such wavelike and, in particular, tidal modulation of the turbulence dissipation field in the MLT region inferred from our analysis is a new finding of this work.

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Section: Discussionmentioning

confidence: 99%

Section: Turbulence Measurementsmentioning

confidence: 99%

Spatial and temporal variability in MLT turbulence inferred from in situ and ground-based observations during the WADIS-1 sounding rocket campaign

et al. 2017

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“…(We should mention that the validity of Eq. (13), which relates the spectral width of the radar echo to the turbulent dissipation rate, has been discussed by Strelnikova and Rapp (2013) for the EISCAT VHF radar for the case when MSPs are present. They noted that there is no theoretical justification for the equation in this case.…”

Section: Discussionmentioning

confidence: 99%

EISCAT and ESRAD radars observations of polar mesosphere winter echoes during solar proton events on 11–12 November 2004

2013

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Abstract. Polar mesosphere winter echoes (PMWE) were detected by two radars, ESRAD at 52 MHz located near Kiruna, Sweden, and EISCAT at 224 MHz located near Tromsø, Norway, during the strong solar proton event on 11–12 November 2004. PMWE maximum volume reflectivity was estimated to be 3 × 10−15 m−1 for ESRAD and 2 × 10−18 m−1 for EISCAT. It was found that the shape of the echo power spectrum is close to Gaussian inside the PMWE layers, and outside of them it is close to Lorentzian, as for the standard ion line of incoherent scatter (IS). The EISCAT PMWE spectral width is about 5–7 m s−1 at 64–67 km and 7–10 m s−1 at 68–70 km. At the lower altitudes the PMWE spectral widths are close to those for the IS ion line derived from the EISCAT data outside the layers. At the higher altitudes the PMWE spectra are broader by 2–4 m s−1 than those for the ion line. The ESRAD PMWE spectral widths at 67–72 km altitude are 3–5 m s−1, that is, 2–4 m s−1 larger than ion line spectral widths modelled for the ESRAD radar. The PMWE spectral widths for both EISCAT and ESRAD showed no dependence on the echo strength. It was found that all these facts cannot be explained by turbulent origin of the echoes. We suggested that evanescent perturbations in the electron gas generated by the incident infrasound waves may explain the observed PMWE spectral widths. However, a complete theory of radar scatter from this kind of disturbance needs to be developed before a full conclusion can be made.

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“…As indicated by the name, it is a weak radar echo that is commonly observed in the polar regions during nonsummer periods. Recent studies on PMWE have reported its characteristics as follows (Kirkwood, ; Latteck & Strelnikova, ; Strelnikova & Rapp, ; Zeller et al, ). PMWE is typically scattered and observed from 55 to 85 km.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Observations of Polar Mesosphere Winter Echoes and Cosmic Noise Absorptions in a Common Volume by the PANSY Radar (69.0°S, 39.6°E)

et al. 2018

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This study focuses on the one-to-one relationship between the morphology of polar mesosphere winter echo (PMWE) and cosmic noise absorption (CNA) as determined by measurements made with a single atmospheric radar, the Program of the Antarctic Syowa mesosphere-stratosphere-troposphere/incoherent scatter (PANSY) radar. CNA was calculated using the noise level in radar signal data collected during May 2013, including data of a solar proton event on 23 May. Using PMWE and CNA data in a common volume, their temporal variations and relation were examined in detail. PMWE altitude was clearly anticorrelated with CNA magnitude in a statistical sense: When a large CNA exceeding 0.50 dB took place, PMWE seemed to concentrate around 65 km and disappear above 70 km. The electron density behind the PMWE was estimated by using the ionospheric model for the auroral zone for the solar proton event. PMWE occurrence roughly coincided with a high electron density in the model, except that no PMWE was observed above 70 km at 0730 UT despite the electron density being higher than 10 8 m −3 . Additionally, the estimated radar volume reflectivity with the Schmidt number Sc less than or equal to 1 is qualitatively consistent with the observed PMWE. Although weak turbulent energy dissipation rate can also play a dominant role in the observed PMWE decay, a plausible mechanism was small Sc or reduction of Sc that is equal to an increase in electron diffusivity resulting from an unusually high electron density, which significantly reduced radar volume reflectivity above 70 km.

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Statistical characteristics of PMWE observations by the EISCAT VHF radar

Cited by 13 publications

References 60 publications

Spatial and temporal variability in MLT turbulence inferred from in situ and ground-based observations during the WADIS-1 sounding rocket campaign

Spatial and temporal variability in MLT turbulence inferred from in situ and ground-based observations during the WADIS-1 sounding rocket campaign

EISCAT and ESRAD radars observations of polar mesosphere winter echoes during solar proton events on 11–12 November 2004

Simultaneous Observations of Polar Mesosphere Winter Echoes and Cosmic Noise Absorptions in a Common Volume by the PANSY Radar (69.0°S, 39.6°E)

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