Relationship Between Climate Index (WMOI, SOI) and Rainfall Variability in Azib Soltane (Sebou basin Marocco)

Abstract

The objective of this study is to understand the inter-annual variability of rainfall in the region Azib Soltane in the Sebou basin and determined the relationship with climatic fluctuations (represented by Western Mediterranean Oscillation Index [WMOI] and South Oscillation Index [SOI]). To attain this objective, the time series of precipitation at Azib Soltane is being studied by continuous wavelet analysis and wavelet coherence analysis, which are particularly adapted to the study of unstable process.The wavelet analysis of rainfall shows the existence of many groups of energy, from the annual to the inter-annual scales. These bands correspond to modes 1 year, 2-4 years, 4-8 years. The wavelet analysis of coherence shows a strong coherence between WMOI / rain, SOI/rain. The discontinuities can be observed in the late 1980s, 1995. The average contribution of climate fluctuations is about of 60%.

Keys words: Climate fluctuation, Morocco, WMOI, SOI, wavelets, and coherence.