Determination of the Structure of the Atmosphere between 90 and 250 km by means of Contaminant Releases at Woomera, May 1968
17 Feb 1972-Philosophical Transactions of the Royal Society A (The Royal Society)-Vol. 271, Iss: 1218, pp 631-663
TL;DR: In this article, a series of measurements of neutral atmospheric wind velocity, turbulent structure, temperature and density were made during each launch between 90 and 250 km altitude, combining the experimental techniques of the two groups involved.
Abstract: Two Skylark rockets were launched from Woomera rocket range, Australia (31 degrees S) on the morning and evening of 31 May 1968. Coordinated series of measurements of neutral atmospheric wind velocity, turbulent structure, temperature and density were made during each launch between 90 and 250 km altitude, combining the experimental techniques of the two groups involved. This paper attempts to construct from the combined measurements made on these occasions a dynamic picture of the interactions of atmospheric structure, and to relate the observations to previous results obtained by ourselves and other workers.
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TL;DR: A variety of dynamical processes are important in coupling motions within the middle atmosphere and lower ionosphere These processes can generally be classified as either advective, wave-like or diffusive as discussed by the authors.
27 citations
TL;DR: A review of the role of turbulence in the coupling between the middle atmosphere and the low levels of the ionosphere is given in this paper, along with a detailed collection of measurements of turbulent eddy diffusion coefficients.
Abstract: Neutral atmosphere turbulence exists almost ubiquitously throughout the atmosphere up to heights of about 100km, and then completely disappears above about 120km altitude. It's importance in providing coupling in the lower regions of the atmosphere (troposphere and stratosphere) is well known, but its importance for coupling between the middle atmosphere and ionosphere is not so well understood. In this review, we will concentrate on the role that turbulence plays in the coupling between the middle atmosphere and the low levels of the ionosphere. The discussion will include a review of some of the important principles of turbulence, as well as some of the unique features about middle atmospheric turbulence. A detailed collection of measurements of turbulent eddy diffusion coefficients will be presented, along with some warnings about how these data should be interpreted. The need to understand turbulence at a very fundamental level in order to apply measurements of such “diffusion coefficients” is stressed.
26 citations
TL;DR: In this article, a spherical model of the solar terminator is presented, and a general solution for pressure field perturbation is obtained with help of equations written in a spherical coordinate system moving with the terminator and which describe acoustic-gravitational wave generation.
23 citations
TL;DR: The Turbopause experiment used four rockets launched over a period of approximately two hours from Poker Flat Research Range, Alaska (64° N, 147° W) on the night of 17-18 February 2009 as discussed by the authors.
Abstract: . Very few sequences of high resolution wind and temperature measurements in the lower thermosphere are available in the literature, which makes it difficult to verify the simulation results of models that would provide better understanding of the complex dynamics of the region. To address this problem the Turbopause experiment used four rockets launched over a period of approximately two hours from Poker Flat Research Range, Alaska (64° N, 147° W) on the night of 17–18 February 2009. All four rocket payloads released trimethyl aluminum trails for neutral wind and turbulence measurements, and two of the rockets carried ionization gauges and fixed-bias Langmuir probes measuring neutral and electron densities, small-scale fluctuations and neutral temperatures. Two lidars monitored temperature structure and sodium densities. The observations were made under quiet geomagnetic conditions and show persistence in the wind magnitudes and shears throughout the observing period while being modulated by inertia-gravity waves. High resolution temperature profiles show the winter polar mesosphere and lower thermosphere in a state of relatively low stability with several quasi-adiabatic layers between 74 and 103 km. Temperature and wind data were combined to calculate Richardson number profiles. Evidence for turbulence comes from simultaneous observations of density fluctuations and downward transport of sodium in a mixed layer near 75 km; the observation of turbulent fluctuations and energy dissipation from 87–90 km; and fast and irregular trail expansion at 90–93 km, and especially between 95 to 103 km. The regions of turbulent trails agree well with regions of quasi-adiabatic temperature gradients. Above 103 km, trail diffusion was mainly laminar; however, unusual features and vortices in the trail diffusion were observed up to 118 km that have not been as prevalent or as clearly evident in earlier trail releases.
23 citations
TL;DR: In this paper, a downleg trail of lithium in morning twilight showed definite turbulent features and also a wave structure at 107 km which could be generated by the intense wind shear.
22 citations
References
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Book•
01 Jan 1954
TL;DR: Molecular theory of gases and liquids as mentioned in this paper, molecular theory of gas and liquids, Molecular theory of liquid and gas, molecular theories of gases, and liquid theory of liquids, مرکز
Abstract: Molecular theory of gases and liquids , Molecular theory of gases and liquids , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
11,807 citations
Book•
01 Jan 1953
TL;DR: In this article, the kinematics of the field of homogeneous turbulence and the universal equilibrium theory of decay of the energy-containing eddies are discussed. But the authors focus on the dynamics of decay and not on the probability distribution of u(x).
Abstract: Preface 1 Introduction 2 Mathematics representation of the field of turbulence 3 The kinematics of homogeneous turbulence 4 Some linear problems 5 General dynamics of decay 6 The universal equilibrium theory 7 Decay of the energy-containing eddies 8 The probability distribution of u(x) Bibliography of research on homogeneous turbulence Index
3,121 citations
TL;DR: In an earlier paper as mentioned in this paper, values of exospheric density were obtained from the orbit of Echo 2 for the years 1964-1965, and the results indicated a semi-annual variation in density by a factor of between 2 and 3, considerably larger than predicted by existing atmospheric models.
17 citations
15 citations