Low frequency oscillations in summer monsoon rainfall over India


  • A CHOWDHURY Meteorological Office, Pune
  • RK MUKHOPADHYAY Meteorological Office, Pune
  • KCSINHA RAY Meteorological Office, Pune




The paper deals with spatial and temporal variations of different frequency modes of the southwest monsoon rainfall over India. Daily normal rainfall data (1901-1970) and that of the individual years for the period 1978-1983 for 220 well distributed stations throughout the country are subjected to harmonic analysis to investigate the contributions of different frequency modes.

The results reveal the presence of 30-60 day periodicities as a predominant mode over central Peninsula in the long term normal as well as individual years. The variance explained by the 10.20 days oscillations exceed that of 30-60 days over central India during the good monsoon years.

In good monsoon years the fundamental mode is predominant north of about 25° N while during the bad monsoon years it extends to more southern latitudes.





How to Cite

A. CHOWDHURY, R. MUKHOPADHYAY, and K. . RAY, “Low frequency oscillations in summer monsoon rainfall over India”, MAUSAM, vol. 39, no. 4, pp. 375–382, Oct. 1988.



Research Papers