Neutral air turbulence in the upper atmosphere observed during the Energy Budget Campaign

Thrane, E. V.; Andreassen, Øyvind; Blix, T. A.; Grandal, B.; Brekke, A.; Philbrick, C. R.; Schmidlin, F. J.; Widdel, H. U.; Zahn, U. von; Lübken, Franz‐Josef

doi:10.1016/0021-9169(85)90136-9

Cited by 77 publications

(26 citation statements)

References 16 publications

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“…Indeed, there have been several in-situ measurements of ion and electron number densities during winter conditions which show fluctuations on the order of 1-5% (much larger than neutral air fluctuations) and conversion factors (1/F) of approximately 5-10 ( Thrane and Grandal, 1981;Thrane et al, 1985Thrane et al, , 1994Lübken et al, 1987Lübken et al, , 1993Blix et al, 1990a,b). The quantity N ϑ determines the total variability of the tracer, together with N e and .…”

Section: Theory Of Turbulent Pmwementioning

confidence: 99%

The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes

et al. 2006

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Abstract. In January 2005, a total of 18 rockets were launched from the Andøya Rocket Range in Northern Norway (69 • N) into strong VHF radar echoes called "Polar Mesosphere Winter Echoes" (PMWE). The echoes were observed in the lower and middle mesosphere during large solar proton fluxes. In general, PMWE occur much more seldom compared to their summer counterparts PMSE (typical occurrence rates at 69 • N are 1-3% vs. 80%, respectively). Our in-situ measurements by falling sphere, chaff, and instrumented payloads provide detailed information about the thermal and dynamical state of the atmosphere and therefore allow an unprecedented study of the background atmosphere during PMWE. There are a number of independent observations indicating that neutral air turbulence has caused PMWE. Ion density fluctuations show a turbulence spectrum within PMWE and no fluctuations outside. Temperature lapse rates close to the adiabatic gradient are observed in the vicinity of PMWE indicating persistent turbulent mixing. The spectral broadening of radar echoes is consistent with turbulent velocity fluctuations. Turbulence also explains the mean occurrence height of PMWE (∼68-75 km): viscosity increases rapidly with altitude and destroys any small scale fluctuations in the upper mesosphere, whereas electron densities are usually too low in the lower mesosphere to cause significant backscatter. The seasonal variation of echoes in the lower mesosphere is in agreement with a turbulence climatology derived from earlier sounding rocket flights. We have performed model calculations to study the radar backscatter from plasma fluctuations caused by neutral air turbulence. We find that volume reflectivities observed during PMWE are in quantitative agreement with theory. Apart from turbulence the most crucial requirementCorrespondence to: F.-J. Lübken (luebken@iap-kborn.de) for PMWE is a sufficiently large number of electrons, for example produced by solar proton events. We have studied the sensitivity of the radar echo strength on various parameters, most important electron number density and turbulence intensity. Our observational and theoretical considerations do not provide any evidence that charged aerosol particles are needed to explain PMWE, in contrast to the summer echoes which owe their existence to charged ice particles.

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Section: Theory Of Turbulent Pmwementioning

confidence: 99%

The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes

et al. 2006

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“…Multistratification of the obtained vertical profiles of the turbulent parameters of the medium (with a layer thickness of 0.1-3 km) is also observed in [1] for the complex relief, in the laboratory experiments modeling the process of convective instability in a stratified fluid [29] and at higher levels of the atmosphere (stratosphere and mesosphere) [30][31][32]. This means that there is much common in the turbulent features of the troposphere, stratosphere and mesosphere: the order of the turbulence coefficients, stratification of the vertical profiles of the Richardson numbers and alternation of the turbulent and laminar layers of the atmosphere.…”

Section: Discussionmentioning

confidence: 80%

On the Wind and Turbulence in the Lower Atmosphere above Complex Terrain

Jandieri¹,

Surmava²,

Gvelesiani³

2011

IJG

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Numerical modeling and studies of the wind fields at the junction of three continents: over the complex terrains of the South-east Europe, Asia Minor, Middle East, Caucasus and over the Black, Caspian and Mediterranean seas have been carried out for the first time. Traveling synoptic scale vortex wave generation and subsequent evolution of orographic vortices are discovered. Wind fields, spatial distribution of the coefficients of subgrid scale horizontal and vertical turbulence and the Richardson number are calculated. It is shown that the local relief, atmospheric hydrothermodynamics and air-proof tropopause facilitate the generation of  -mesoscale vortex and turbulence amplification in the vicinity of the atmospheric boundary layer and tropopause. Also turbulence parameters distribution in the troposphere has the same nature as in the stratosphere and mesosphere: turbulence coefficients, stratification of the vertical profiles of the Richardson number, thickness of the turbulent and laminar layers.

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“…6.1 The "constant" γ γ γ γ γ γ γ γ Despite the above expectation about a Richardson-number dependence of γ , for a while this dependence was all but ignored in the literature, and γ was indeed taken as a constant. Examples include Van Zandt et al (1978, Gage (1980), as well as Hocking (1985), Thrane et al (1985Thrane et al ( , 1987, Lübken et al (1987) and Blix et al (1990). Note that in the last four cases, it was not actually C 2 n , the potential refractive index gradient structure "constant", which was measured, but rather one of the neutral, ion or electron density structure "constants".…”

Section: Scalar Spectral Methods For Measuringmentioning

confidence: 99%

“…We have chosen the rocket data obtained by Thrane et al (1985Thrane et al ( , 1987, Lübken et al (1987), and Blix et al (1990), which have been nicely tabulated in those references. We have converted the energy dissipation rates produced by these authors back to effective structure constants (analagous to C 2 n but in this case they were ion or electron density or neutral density structure constants), and then re-determined ε using Eqs.…”

Section: Application Of the New Cmentioning

confidence: 99%

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The dynamical parameters of turbulence theory as they apply to middle atmosphere studies

Hocking

2014

Earth Planet Sp

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The study of turbulent heating and diffusion in the middle atmosphere is complicated by some subtle points relating to the application of existing theory. Incorrect interpretation of turbulent spectra can result, leading to errors in estimates of the strengths of turbulence by factors of 5 and more. In this short review, the relevant turbulent spectra and equations are considered, and their applications in middle atmosphere studies are outlined. New developments with regard to some of this theory, and especially new understandings about the dynamical parameters used in some of these applications (often referred to as the "constants" of the equations) are described. Current areas of uncertainty are also considered, both in relation to turbulent energy dissipation as well as diffusion over various scales.

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Neutral air turbulence in the upper atmosphere observed during the Energy Budget Campaign

Cited by 77 publications

References 16 publications

The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes

The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes

On the Wind and Turbulence in the Lower Atmosphere above Complex Terrain

The dynamical parameters of turbulence theory as they apply to middle atmosphere studies

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