Anomalous Seasonal Variation of Radio Waves in the VLF, LF, MF & HF Bands in relation to Middle Atmospheric Phenomena

Abstract

Seasonal variations of radio waves in the VLF, LF, MF and HF bands have been critically examined. Observations in the tropical region Calcutta indicate an anomalous additional maximum in signal strength of radio waves in summer with a prominent minimum in October. Examination of the data reveals that the anomaly may be related to the diffusion of hydrated cluster of positive ions H⁺(H₂O)<i>_n</i> from the lower atmosphere to the lower ionospheric heights.