Turbulent energy dissipation rates from the University of Tromsø/University of Saskatchewan MF radar

Hall, C. M.; Meek, C. E.; Manson, A. H.

doi:10.1016/s1364-6826(97)00124-7

Cited by 19 publications

(19 citation statements)

References 15 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%

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%

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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“…Hall and Husøy (2004) compared altitudes of tidal phases observed by the MFR and NTMR respectively, confirming the conclusion using careful measurements of delays in the MFR system (employing a delay line to resolve ambiguities), and therefore resolving the earlier uncertainty in the MFR altitude calibration. Thus, a correlation between the departure of the diffusion coefficient yielded by NTMR, from the expected exponential profile, with estimates of the turbulent energy dissipation rate obtained from the MFR (Hall et al, 1998), would be a prima facie ratification the Hall (2002) mechanism.…”

Section: Introductionmentioning

confidence: 94%

<i>Letter to the Editior</i>Testing the hypothesis of the influence of neutral turbulence on the deduction of ambipolar diffusivities from meteor trail expansion

Hall¹,

Asô

Tsutsumi

et al. 2005

Ann. Geophys.

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Abstract. Fading times of radar echoes from underdense meteor trails in the upper mesosphere/lower thermosphere are commonly used to determine ambipolar diffusivities and hence ambient temperature. Diffusivities are generally expected to increase exponentially with height through the region from which the meteor trail echoes are obtained, viz., typically 70-110 km altitude for a ∼30-MHz radar. In practice, however, this is more the exception: unexpectedly large diffusivities are obtained in the lower part of the regime, and unexpectedly low values are obtained in the upper part; only in the few kilometres on either side of the maximum in echo occurrence (viz., 90 km for a 30-MHz radar) does the diffusivity profile behave as expected. Hall (2002) hypothesised that neutral turbulence might be enhancing expansion of the meteor trail in the lower part of the regime. In this communication, due to results only available since the publication of Hall's suggestion, we are able to refute the hypothesis.

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“…Systematic measurements of ε and K at different altitudes were made using MF, MST and UHF radars (e.g. Kurosaki et al, 1996;Naström and Eaton, 1997;Hall et al, 1998;Bertin et al, 1999;Dole and Wilson, 2001;Satheesan and Krishna Murthy, 2002;Kelly et al, 2003;Zink et al, 2004), and with acoustic (Agrovskii and Kukharets, 1998;Furumoto and Tsuda, 2001) and optical measurements (Kao et al, 2002;Hecht et al, 2004). Recently, extensive information about profiles of turbulence characteristics was obtained from optical observations of star scintillations from satellites (Gurvich et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Turbulence parameter estimations from high-resolution balloon temperature measurements of the MUTSI-2000 campaign

et al. 2005

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Abstract. Turbulence parameters in the tropo-stratosphere are analyzed using high-resolution balloon temperature measurements collected during the MUTSI (MU radar, Temperature sheets and Interferometry) campaign which took place near the Middle and Upper atmosphere (MU) radar (Japan, 35 • N, 136 • E) in May 2000. Vertical profiles of the specific dissipation rate of turbulent kinetic energy, ε, and turbulent diffusivity, K, are estimated from the Thorpe lengthscale, L T . The last is obtained by using two methods. The first one consists of measuring directly L T by reordering the potential temperature profiles. The second method is based on estimates of the temperature structure constant, C 2 T . A relationship between L T and C 2 T can be found by assuming either adiabatic vertical displacements or a model based on turbulent energy balance consideration. Analysis shows that the adiabatic assumption gives indirect estimates of L T more consistent with direct measurements. We also found that vertical profiles of analyzed turbulence characteristics show substantial intermittency, leading to substantial scatter of the local, median and average values. General trends correspond to a decrease in ε and K from the boundary layer up to altitudes 20-25 km. Layers of increased turbulence are systematically observed in the tropo-stratosphere, which may be produced by instabilities of temperature and wind profiles. These maxima may substantially increase local values of turbulence diffusivity.

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Turbulent energy dissipation rates from the University of Tromsø/University of Saskatchewan MF radar

Cited by 19 publications

References 15 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

<i>Letter to the Editior</i>Testing the hypothesis of the influence of neutral turbulence on the deduction of ambipolar diffusivities from meteor trail expansion

Turbulence parameter estimations from high-resolution balloon temperature measurements of the MUTSI-2000 campaign

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Turbulent energy dissipation rates from the University of Tromsø/University of Saskatchewan MF radar

Cited by 19 publications

References 15 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

&lt;i&gt;Letter to the Editior&lt;/i&gt;Testing the hypothesis of the influence of neutral turbulence on the deduction of ambipolar diffusivities from meteor trail expansion

Turbulence parameter estimations from high-resolution balloon temperature measurements of the MUTSI-2000 campaign

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<i>Letter to the Editior</i>Testing the hypothesis of the influence of neutral turbulence on the deduction of ambipolar diffusivities from meteor trail expansion