F layer


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Related to F layer: E layer, D layer

F layer

[′ef ‚lā·ər]
(geophysics)
An ionized layer in the F region of the ionosphere which consists of the F1 and F2 layers in the day hemisphere, and the F2 layer alone in the night hemisphere; it is capable of reflecting radio waves to earth at frequencies up to about 50 megahertz.

F layer

F layerclick for a larger image
An ionized layer of atmosphere located approximately 90 to 240 miles (150-400 km) above the earth. This layer plays an important role in radio communications and reflects electromagnetic emissions from 1.5 to above 30 MHz. The height of the F layer varies, depending on the seasons and whether it is day or night. It is divided into two layers: F1 and F2. The F2 layer is always present and has a higher electron density than the F1 layer. F1 is the lower of the two and has a higher level of ionization.