Directional and Diurnal Characteristics of Auroras at Some Places in Canada
Currie, B. W.; Jones, C. K.
Журнал:
Terrestrial Magnetism and Atmospheric Electricity
Дата:
1941
Аннотация:
Introduction—Observations of auroras at almost all places on the Earth's surface indicate that displays extend along some predominating horizontal direction and that the maximum diurnal activity occurs at a particular time, both of which are typical of the locality in question. Vegard [see 1 of “References” at end of paper] has shown that the average directions of arcs and bands at a number of the places in the Northern Hemisphere are systematized and assume added significance if they are referred to the geomagnetic rather than to the astronomical meridians. In most cases the average angle between the westward‐directed end of the arcs and bands observed at a particular place and the geomagnetic meridian through the place is several degrees greater than 90°. Vegard [1, 2] has examined also the diurnal frequency of auroras for a number of northern stations, and has expressed the opinion that within the limit of error the principal maximum occurs at about one hour before geomagnetic midnight. On the other hand Hulburt [3] from the data of many arctic and antarctic expeditions suggests that the diurnal course of an auroral display is dependent upon the meteorology of the upper atmosphere at a station.
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