Talat Parveen^1,, Shaik Abdul Muneer², Rehman. M.K³, Aleem Basha. H³

Every year there were regular atmospheric oscillation representing in the form of convection and precipitation. This article elicits the fluctuations in atmospheric oscillation which have been modulated by various atmospheric effects altering convection in different regions over India. The semi-annual and annual oscillation occurring in the atmosphere can be observed through some atmospheric indices. To assess the amplitude and frequency of these oscillations, we have used atmospheric index i.e Lifted index over six regions, New Delhi, Mumbai, Kolkata, Hyderabad, Bengaluru and Chennai for the duration January 1996 to December 2016. To extract information we have implemented Singular Spectrum Analysis which decomposes data and to find amplitude and frequency we implemented Fast Fourier Transformation. From FFT it is observed that the annual and semiannual amplitudes of Lifted Index of six stations lie between 2°C to 6°C and 1.5°C to 2°C respectively. Kolkata has annual amplitude value of 6.041°C and semiannual amplitude value of 3.643°C which are more as compared to other stations. Chennai has least annual amplitude value of 2.403°C and Bengaluru has least semiannual amplitude value of 1.342°C. Even though Kolkata and Chennai are coastal regions near Bay of Bengal, variation in maximum and minimum magnitudes of Kolkata are more as compared to Chennai and hence Kolkata might have more convection and precipitation. The results from this study are mostly consistent with the previous studies. A detailed inferences of these results are discussed.

lifted index, principal components, spectrum, amplitude and frequency