LONG-PERIOD FADING IN ATMOSPHERICS DURING SEVERE METEOROLOGICAL ACTIVITY AND ASSOCIATED SOLAR GEOPHYSICAL PHENOMENA AT LOW LATITUDES

The records of VLF atmospherics over Calcutta and then over Kalyani (W est Bengal) during the torrential rainfall, caused by violent monsoon and post-monsoon depressions, exhibit distinct long-period fadings bot h at day and night. Interesting results obtained from an analysis of r ound-the-clock atmospherics data and associated meteorological paramet ers are reported in this paper. A possible correlation between the sev ere meteorological activity with the solar geophysical phenomena was s tudied. The results are indicative of an interesting sequence of solar -terrestrial events. A tentative conclusion is reached, suggesting an origin of the fading from atmospheric gravity waves generated in the c entre of activity of the depressions concerned.