Some horizontally-moving ionospheric irregularities at high latitudes
Two large-scale, horizontally-moving 'frontal' ionospheric irregularities were identified on bottom-side ionograms recorded at several stations separated by distances ∼1000 km at high northern latitudes. Each irregularity appeared as a vertical set of horizontally-moving echoes at height i...
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
1968
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| Online Access: | https://espace.library.uq.edu.au/view/UQ:393805 |
| Summary: | Two large-scale, horizontally-moving 'frontal' ionospheric irregularities were identified on bottom-side ionograms recorded at several stations separated by distances ∼1000 km at high northern latitudes. Each irregularity appeared as a vertical set of horizontally-moving echoes at height intervals of approximately 11 km from 111 to 165 km. The echoes were considered to be produced by interference amongst the members of a train of interval gravity waves reflected at a height of about 170 km at a negative scale-height gradient. Horizontal and vertical wavelengths of the internal gravity wave-motion were 800km and ∼13km respectively, and the periodicity was 7·6 hr. It appears that 'troughs' of ionization density (recorded on topside ionograms) and the present irregularities were manifestations of the same set of travelling ionospheric disturbances. They were apparently produced by a train of internal gravity waves whose horizontal motion originated in the vicinity of the North Geomagnetic Pole. The irregularities were produced at a time of enhanced ionospheric absorption indicative of increased geomagnetic activity. |
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