‘Winter Anomaly’ in Ionospheric Absorption and Stratospheric Warmings

Shapley, A. H.; Beynon, W.J.G.

doi:10.1038/2061242a0

Cited by 67 publications

(18 citation statements)

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“…A strong dependence of the phenomenon on the sunspot activity is noticed with over 80% of the days being anomalous at the latitude of Slough [Appleton and Piggott, 1954] during the maximum of sunspot activity. Shapley and Beynon [1965] have shown a much lower occurrence frequency, once every five to eight days, at Lindau during a different solar epoch.…”

Section: Principal Features Of the Anomalymentioning

confidence: 99%

“…The region of enhanced attenuation has not been identified, nor have the relative roles of the electron collision frequency and electron number density in producing the anomaly been clarified. The phenomenon has been associated with the pressure ridges in the troposphere [Gregory, 1965], and with stratospheric warming events [Shapley and Beynon, 1965]. BeYnon and Jones [1965] have attributed the phenomenon partly to changes in the collision frequency of electrons with neutral particles and partly to changes in the electron number denx On leave of absence from the Physical Research Laboratory, Navarangpura, Ahmedabad 9, India. 2 Present address: IIT Research Institute, Chicago, Illinois.…”

Section: Introductionmentioning

confidence: 99%

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Criteria for recognition of a winter day of high ionospheric absorption

Shirke¹,

Rao²

1967

J. Geophys. Res.

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Criteria for identifying a winter day with anomalous ionospheric absorption have been established from ground‐based measurements for use when launching rockets to study the D layer under these conditions. The criteria are based on measurements of vertical incidence ionospheric absorption of 3.03 Mc/s at Wallops Island, Virginia, during the winter of 1965–1966 using an automatic recording system. The nature of the partial reflections observed from very low altitudes during an anomalous day and certain other features noticeable on a sensitive ionosonde are discussed. A new method of data analysis is presented whereby it is possible to separate the absorption below and above the normal E‐region level in the ionosphere, using single‐frequency measurements. Normally, a substantial part of the total absorption is shown to arise above 110 km depending largely on the virtual height of reflection of the echo. The anomalous absorption originating much below the 110‐km level is shown to be about 8 db at its noon maximum. Various other features of the anomalous absorption are investigated including its diurnal variation, which is shown to be similar to that on the control days.

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Section: Principal Features Of the Anomalymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Criteria for recognition of a winter day of high ionospheric absorption

Shirke¹,

Rao²

1967

J. Geophys. Res.

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“…Thus BOSSOLASCO and ELENA (1963) have demonstrated that a strong correlation exists between the temperature at the 10-millibar level and midlatitude winter radio wave absorption at frequencies around 2 Mc/s. Also AIKIN et al (1964) and SHAPLEY and BEYNON (1965) have shown that the electron collision frequency is subject to significant variations of a meteorological nature.…”

Section: Variations In Collision Frequencymentioning

confidence: 99%

Ionospheric absorption of cosmic radio noise

Hultqvist¹

1966

Space Sci Rev

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The development of the field of study of ionospheric absorption of cosmic radio noise since 1962 is reviewed. Contributions to the basic theory and methods of analysis are first dealt with. News concerning measuring technique are then briefly treated. In the main part of the paper the development of our knowledge of sudden cosmic noise absorption, polar cap absorption, and auroral absorption is reviewed. The emphasis is on the ionospheric effects. The solar disturbances associated with the absorption effects, the propagation of particles from the Sun to the Earth, and other extraterrestrial sides of the story are not treated.

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“…The stratospheric temperature at middle and high latitudes is known to undergo large fluctuations during the winter months, and there is some evidence that it correlates with the unexpectedly high absorption observed in winter (Bossolasco andElena 1963, Shapley andBeynon 1965), generally referred to as the "winter anomaly". It has not been possible to determine whether a similar association exists at the equator between absorption and upper atmospheric meteorology because synoptic measurements of the latter are not available from low latitudes.…”

Section: Absorption Enhancements In the Absence Of X-ray Activitymentioning

confidence: 99%

Equatorial ionospheric absorption during half a solar cycle (1964–1970)

Gnanalingam

1974

Journal of Atmospheric and Terrestrial Physics

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‘Winter Anomaly’ in Ionospheric Absorption and Stratospheric Warmings

Cited by 67 publications

References 1 publication

Criteria for recognition of a winter day of high ionospheric absorption

Criteria for recognition of a winter day of high ionospheric absorption

Ionospheric absorption of cosmic radio noise

Equatorial ionospheric absorption during half a solar cycle (1964–1970)

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