A Determination of the Daytime Thermospheric Wind Profile by Observing a Lithium Trail with a Field-of-view Scanner

Hind, A. D.; Lloyd, KH

doi:10.1071/ph740401

Cited by 6 publications

(6 citation statements)

References 4 publications

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“…The estimated vertical wavelength of the measured winds is roughly 20–30 km, indicative of either diurnal or semidiurnal tides (e.g., J. Forbes, 1995) although such variations may also be due to gravity waves. We note that a similar spiral structure was observed in wind measurements by Hind and Lloyd (1974). Those researchers reported a counter‐clockwise rotation that they attributed to the fact their observations were gathered in the southern hemisphere.…”

Section: Discussionsupporting

confidence: 87%

“…Daytime wind measurements using vapor trails, as reported herein, are very scarce, with only two experiments reporting daytime wind observations at midlatitudes in the lower ionosphere, including Hind and Lloyd (1974) from Australia and Rees et al (1979) from Wallops. Both sets of observations showed moderate-to large-amplitude winds with spiral structure although no association with the dynamo current systems was reported.…”

Section: Research Lettermentioning

confidence: 84%

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Daytime Dynamo Electrodynamics With Spiral Currents Driven by Strong Winds Revealed by Vapor Trails and Sounding Rocket Probes

Pfaff

Larsen

Abe

et al. 2020

Geophysical Research Letters

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We investigate the forces and atmosphere‐ionosphere coupling that create atmospheric dynamo currents using two rockets launched nearly simultaneously on 4 July 2013 from Wallops Island (USA), during daytime Sq conditions with ΔH of −30 nT. One rocket released a vapor trail observed from an airplane which showed peak velocities of >160 m/s near 108 km and turbulence coincident with strong unstable shear. Electric and magnetic fields and plasma density were measured on a second rocket. The current density peaked near 110 km exhibiting a spiral pattern with altitude that mirrored that of the winds, suggesting the dynamo is driven by tidal forcing. Such stratified currents are obscured in integrated ground measurements. Large electric fields produced a current opposite to that driven by the wind, believed created to minimize the current divergence. Using the observations, we solve the dynamo equation versus altitude, providing a new perspective on the complex nature of the atmospheric dynamo.

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Section: Discussionsupporting

confidence: 87%

Section: Research Lettermentioning

confidence: 84%

Daytime Dynamo Electrodynamics With Spiral Currents Driven by Strong Winds Revealed by Vapor Trails and Sounding Rocket Probes

Pfaff

Larsen

Abe

et al. 2020

Geophysical Research Letters

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“…Lithium and sodium have still been used for special applications, however. Lithium, for example, which produces an exceptionally bright resonant emission was used in several studies to measure the daytime neutral winds in the ionosphere [ Rees et al , 1972a; Bedinger , 1973a; Hind and Lloyd , 1974].…”

Section: Data Set Descriptionmentioning

confidence: 99%

Winds and shears in the mesosphere and lower thermosphere: Results from four decades of chemical release wind measurements

2002

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[1] Since 1958, over 400 chemical tracer measurements have been made of the wind profiles in the upper mesosphere and lower thermosphere. The measurements cover a wide range of latitudes, longitudes, seasons, and local times. The results from the analysis of the data set show that a wind maximum in the altitude range between 100 and 110 km is a consistent feature of the observations at midlatitudes and low latitudes. The wind speed associated with the maximum exceeds 100 m s À1 in over 60% of the observations. Large shears are found, especially on the bottomside of the wind maximum, and the observed shears are often large enough to be either unstable or approaching instability. The wind maximum and shear features are characteristics of the overall data set and are not tied to particular observation sites, particular seasons, or special conditions. INDEX TERMS: 3369

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“…The lithium trail technique saw a renewed interest in the 1970's as a technique for measuring daytime E-region winds (e.g., Bedinger, 1973;Hind and Lloyd, 1974). The lithium line is sufficiently bright so that the trails could be detected in daylight conditions with the improved narrow- band filters.…”

Section: Introductionmentioning

confidence: 99%

Rocket-borne Lithium ejection system for neutral wind measurement

Habu¹,

Yamamoto²,

Watanabe³

et al. 2013

An Introduction to Space Instrumentation

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Chemical tracer releases represent the most widely used technique for in situ neutral wind measurements in the thermosphere/ionosphere region. Different chemicals have been used for this purpose, but lithium releases in particular provide some unique capabilities due to the strong resonant emissions that are produced when lithium is illuminated by sunlight. The majority of the lithium releases from sounding rockets were carried out in the 1960's and 1970's, but there has been recent renewed interest in the use of lithium vapor releases to extend neutral wind measurements into the F region and for daytime wind profile measurements in the E region. The rocketborne Lithium Ejection System (LES) is a chemical release device that has been developed for the Japanese space research program. Since lithium vapor acts as a neutral tracer, the winds are obtained by tracking the motion of the clouds or trails optically from the ground using the bright red emission that is characteristic of the chemical. Lithium is a solid at room temperature, so that a gas release requires rapid vaporization of the metal to make the cloud at the intended altitude. The release canister is designed to produce a high-heat chemical reaction without gaseous products. Appropriate mixtures of thermite are employed as the heat source. In early experiments, lithium pellets were mixed directly into the thermite. However, since lithium is an active chemical, the use of lithium-thermite mixtures creates potential hazards when used in a rocket-borne device. Moreover, the pyrotechnic devices used to ignite the thermite also have to be considered in the payload canister design to assure that the safety standards for sounding rockets are satisfied. The design of the LES, described in this paper, was based on the safety requirements and the reliability in storing and handling of the materials. The LES design is also flexible in that the lithium tracer material can be replaced with other chemicals without difficulties. This paper introduces the design of the LES and the method for controlling the thermite burn.

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A Determination of the Daytime Thermospheric Wind Profile by Observing a Lithium Trail with a Field-of-view Scanner

Cited by 6 publications

References 4 publications

Daytime Dynamo Electrodynamics With Spiral Currents Driven by Strong Winds Revealed by Vapor Trails and Sounding Rocket Probes

Daytime Dynamo Electrodynamics With Spiral Currents Driven by Strong Winds Revealed by Vapor Trails and Sounding Rocket Probes

Winds and shears in the mesosphere and lower thermosphere: Results from four decades of chemical release wind measurements

Rocket-borne Lithium ejection system for neutral wind measurement

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