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Published April 1, 2021 | Version version 0.1
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Wavelet & Fourier Analysis on the ENSO and monsoon data in Python

  • 1. Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan

Description

I applied the Wavelet analysis on the quarterly dataset for El Niño–Southern Oscillation (ENSO) sea surface temperature in degree Celsius (1871-1997) and Indian monsoon rainfall in mm (1871-1995). I compared the results with the Fourier Transform. For the analysis of the ENSO dataset, we see that most of the power is concentrated in a 2 to 8 year period (or 0.125-0.5 Hz). For the Indian monsoon dataset, although the power is evenly distributed across different periods, there is also a slight shift in power from longer periods to shorter periods as time progresses. We also found that the Wavelet Transform helps in visualizing the dynamic behavior of the signals.

Files

wavelet-fourier-transform-enso-monsoon-data-main.zip

Files (2.6 MB)

Additional details

References

  • Chao, B. F., Chung, W., Shih, Z., & Hsieh, Y. (2014). Earth's rotation variations: A wavelet analysis. Terra Nova, 26(4), 260–264. https://doi.org/10.1111/ter.12094
  • Franks, L. E. (1969). Signal theory.
  • Papoulis, A. (1977). Signal analysis (Vol. 191). McGraw-Hill New York.
  • Torrence, C., & Compo, G. P. (1998). A practical guide to wavelet analysis. Bulletin of the American Meteorological Society, 79(1), 61–78.