Über die ursache der exzessiven absorption in der ionosphäre an wintertagen

Dieminger, Walter

doi:10.1016/0021-9169(52)90074-3

Cited by 54 publications

(7 citation statements)

References 9 publications

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“…They found echoes below the E region (~110 km) and which extended down to heights of about 80 km. Their results were obtained at MF using an ionosonde and were followed by similar results at MF and HF obtained by Dieminger (1952), Dieminger and Hofmann-Heyden (1952), and by Gnanalingham and Weekes (1952).…”

Section: Brief Historical Overviewsupporting

confidence: 67%

“…For example, Dieminger (1952), Gregory (1956Gregory ( , 1961, Titheridge (1962), Reid (1990), Jones et al (2004), and Hall et al (2006) discuss this for MF and HF, Bailey et al (1955) and Pineo (1956) for very high frequency (VHF; 30 to 300 MHz) forward scatter results, Bowles et al (1964) for both vertical and forward scatter VHF results, and Flock and Balsley (1967) for vertical incidence VHF results. At MF/HF, such preferred heights are subject to seasonal and annual variations, but persistent echoes occur from mean heights of about 65-68, 74-75, 83-85, and 92 km.…”

Section: Brief Historical Overviewmentioning

confidence: 99%

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MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Reid

2015

Prog. in Earth and Planet. Sci.

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The application of medium-frequency (MF) and high-frequency (HF) partial reflection radar to investigate the neutral upper atmosphere is one of the oldest such techniques still regularly in use. The techniques have been continuously improved and remain a robust and reliable method of obtaining wind velocities, turbulence intensities, electron densities, and measurements of atmospheric structure in the mesosphere lower thermosphere (MLT) region (50 to 110 km). In this paper, we review recent developments, discuss the strengths and weaknesses of the technique, and consider possible improvements.

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Section: Brief Historical Overviewsupporting

confidence: 67%

Section: Brief Historical Overviewmentioning

confidence: 99%

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Reid

2015

Prog. in Earth and Planet. Sci.

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“…This indicates that large variations take plaee in the D-layer ionization. Such variations were indirectly observed by Dieminger [1952], and Belrose [1965] has recently obtained the D-layer electron number-density profile during an anomalous day, which shows a significant enhancement in the electron density.…”

Section: Introductionmentioning

confidence: 63%

“…An alternative theory that has been forwarded to explain the irregular day-to-day variations in the D-layer profile is based on the assumption that minor constituents are present that drastically change the effective rate coefi%ients in the upper atmosphere. At present we do not know which negative ions are the most important ones in the lower ionosphere [Reid, 1964], and there are significant discrepancies between various measurements of the abundances of various minor constituencies [Godson, 1960;Dutsch, 1963;Venkateswaran et al, 1961;and Johnson et al, 1952]. Day-today changes in the abundance of these elements that could account for the winter anomaly have so far never been studied experimentally.…”

Section: Introductionmentioning

confidence: 99%

On the ‘winter anomaly’ in the midlatitudeDregion

Maehlum¹

1967

J. Geophys. Res.

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Two causes are often proposed for the ‘winter anomaly,’ i.e. for the excess winter absorption of high‐frequency waves reflected from the ionosphere at midlatitudes. It has been suggested on the one hand that meteorological effects might be responsible, but no detailed proof is available at present. The alternative explanation as being the precipitation of energetic charged particles was often rejected because of such features of the winter anomaly as its apparent lack of correlation with geomagnetic activity. However, in this note, actual measurements of precipitated electrons are shown to yield good correlation with the ionospheric effects. Furthermore, it is shown that the ‘anomalous’ absorption is correlated at magnetically conjugate stations, as one would expect if precipitated particles were responsible. It is therefore demonstrated quantitatively that the winter anomaly can be explained at least partly, as being due to precipitated electrons.

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“…Usually regarded as being distinct from the poststorm effects is the D region 'winter anomaly,' which is defined in terms or' the increased and highly irregular day-to-day variation of absorption of H F waves reflected from the ionosphere at middle latitudes during winter conditions [Appleton and Piggott, 1954;Dieminger, 1952;Thomas, 1962]. In contrast to the long-lived ionospheric effects described above there have also been observations of short-lived (approximately a few hours duration) D region disturbances at middle latitudes.…”

Section: Introductionmentioning

confidence: 99%

A coordinated study of energetic electron precipitation andDregion electron concentrations over Ottawa during disturbed conditions

Larsen¹,

Reagan²,

Imhof³

et al. 1976

J. Geophys. Res.

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This article presents the results of a study of the energetic electron precipitation as well as important parameters of the D region over Ottawa (45°N, 76°W) during lightly to moderately disturbed conditions, using data for the period following the December 17, 1971, magnetic storm as well as data obtained on other selected days exhibiting anomalous D region absorption. Following the December 17, 1971, storm, significant fluxes of precipitating electrons of > 130 keV were observed near Ottawa, even during the poststorm period on December 20, when the geomagnetic activity had subsided (∑ Kp = 6). The excess ionization detected at D region altitudes above Ottawa can be explained as being due to ionization from a prolonged electron drizzle from the outer radiation belt. For the first time it has been proven that precipitating electrons from the radiation belt were the main cause of D region poststorm conditions of middle latitudes. The ground‐based radio probing measurements of the free electron concentration have been coordinated with simultaneous satellite observations of the quasi‐trapped and precipitating electron environment above the site. From the ground‐based measurements, by using the partial reflection technique at two frequencies (2.66 and 6.275 MHz), electron concentration profiles for altitudes between ≈ 60 and 90 km have been derived at times when the low‐altitude polar‐orbiting satellite 1971‐089A passed near Ottawa. On board this satellite, electron differential fluxes in 260 channels and at two pitch angles were measured at energies between ≈1 and ≈2800 keV. The ion pair production rate height profiles due to precipitating electrons were computed for D region heights by using nonisotropic energy‐dependent pitch angle distributions. Effective electron loss rates were deduced for heights between 63 and 91 km. These results indicate a significant variability in loss rates in the altitude range 75–85 km.

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Über die ursache der exzessiven absorption in der ionosphäre an wintertagen

Cited by 54 publications

References 9 publications

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

On the ‘winter anomaly’ in the midlatitudeDregion

A coordinated study of energetic electron precipitation andDregion electron concentrations over Ottawa during disturbed conditions

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