Modeling ELF atmospheric noise

A computer program for predicting extremely low frequency (ELF, 30 to 300 Hz) radio noise is described. The authors review the characteristics of noise in this band and describe how the computer program's predictions compare to data. The current version of the program, called LNP (long-wave noise prediction), predicts horizontally and vertically polarized noise under both ambient and disturbed conditions. In general, LNP is shown to work well at ELF. It is especially surprising that the code gives such good agreement with high latitude data down to 10 Hz, since the waveguide mode propagation approximation starts to become invalid below around 40 Hz.<
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