Worldwide atmospheric gravity-wave study 1985–1989

Williams, P. J. S.; Virdi, T. S.; Owen, Geraint; McCrea, I. W.; Lester, M.; Freeman, K. S. C.

doi:10.1016/0273-1177(92)90056-4

Cited by 7 publications

(3 citation statements)

References 7 publications

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“…Properties of traveling atmospheric/ionospheric disturbances (TAD/TID) and their ionospheric signatures were previously studied in multiple observational (e.g. Rice et al, 1988;Williams et al, 1991Williams et al, , 1993Hocke and Shlegel, 1996) and modeling efforts (e.g. Millward et al, 1993a, b;Lu et al, 2001).…”

Section: Article In Pressmentioning

confidence: 99%

Observations of a positive storm phase on September 10, 2005

Гончаренко

Foster

Coster

et al. 2007

Journal of Atmospheric and Solar-Terrestrial Physics

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Section: Article In Pressmentioning

confidence: 99%

Observations of a positive storm phase on September 10, 2005

Гончаренко

Foster

Coster

et al. 2007

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Francis [1975], in an early review, relied on observations of traveling ionospheric disturbances (TIDs) to illustrate the properties of naturally occurring large-scale waves expected to travel entirely in the thermosphere. Recently, key observations at midlatitudes in the coordinated Worldwide Atmospheric Gravity Wave Study [Williams et al, 1991[Williams et al, , 1993 used observations of ionospheric signatures. However, the interpretation of the ionospheric perturbations in terms of the causative gravity waves is not necessarily straightforward.…”

Section: Introductionmentioning

confidence: 99%

Effects of an atmospheric gravity wave on the midlatitude ionospheric F layer

Millward¹,

Moffett²,

Quegan³

et al. 1993

J. Geophys. Res.

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A modeling study of the atmospheric response to a single short burst of enhanced ion convection at high latitudes, undertaken using the Sheffield/University College London/Space Environment Laboratory coupled ionosphere/thermosphere model, has revealed a large‐scale atmospheric gravity wave (AGW) moving equatorward from a source in the dawn sector auroral zone. The wave propagates to midlatitudes, perturbing the ionosphere and creating a traveling ionospheric disturbance. Analysis of the interaction between the thermosphere and ionosphere during the passage of the AGW at midlatitudes is undertaken and reveals a complex height‐dependent response. At lower altitudes the field‐aligned velocity of the ions follows closely the field‐aligned wind. Above the F peak, diffusion processes become important and the field‐aligned ion velocity shows fluctuations which exceed those in the wind. Changes in NmF2 and hmF2, during the interaction, are due to redistribution of plasma alone with changes in production and loss insignificant. As the F layer is lifted by the positive surge in the gravity wave, NmF2 decreases, due to a divergence in the ion flux, itself caused by the combination of a divergent neutral wind and an increase in the effects of diffusion with altitude. The slab thickness also increases. Subsequently, the opposite happens as hmF2 falls below its equilibrium value.

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“…Furthermore, also unlike Esq, these chaotic echoes may occur by total reflection; we shall examine some evidence for this. The observations are part of a 5-day European incoherent scatter (EISCAT) "WAGS" campaign [Williams et al, 1992]; the Troms0 dynasonde operated throughout with one ionogram each 3 min. All aspects of the sequence to be described (April 11, 1988) are repeated on the following day in surprisingly faithful detail.…”

Section: Quiet Daytime Auroral-latitude Ionogramsmentioning

confidence: 99%

Chaotic echoes on ionograms: Underdense scattering or total reflections?

Wright¹,

Argo²

1994

Radio Science

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Apart from spread F and some forms of sporadic E, little attention is usually paid to the variable occurrence of “chaotic” or disordered “scatter” in ionosonde measurements. In contrast to the echoes of broad radio bandwidth and high amplitude from the plane‐stratified ionosphere, for which total internal reflection is unmistakably applicable, the processes responsible for occasional scattering are not obvious. With the multiparameter information of a digital ionosonde it should be possible to develop criteria by which the echoing processes can be decided, if not on an echo‐by‐echo basis, at least for groups of echoes that bear similar properties. The distinction is important since these chaotic echoes may be identified with significant physical processes, whereupon the ionosonde becomes one of their more powerful diagnostics. Three examples illustrate these points; they arise in consequence of (1) the (magnetic) equatorial electrojet; (2) some suggested neutral‐atmosphere interactions near sporadic E at mid latitudes; and (3) the auroral electrojet, respectively.

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Worldwide atmospheric gravity-wave study 1985–1989

Cited by 7 publications

References 7 publications

Observations of a positive storm phase on September 10, 2005

Observations of a positive storm phase on September 10, 2005

Effects of an atmospheric gravity wave on the midlatitude ionospheric F layer

Chaotic echoes on ionograms: Underdense scattering or total reflections?

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