Abstract
Trends and variations in the frequencies of cyclonic disturbances as well as cyclonic storms over the Bay of Bengal in the post-monsoon season are studied using 100 years (1800–1979) of data. Power spectral study of the cyclones has been made and periods at 3.0 and 2.1 years in the cyclonic disturbances and 35−40, 3.0 and 2.1 years in the cyclonic storms have been noted to be significant.