A Physical Study of River RamGanga by using Complex Morlet Wavelets

Abstract

Wavelets provide local information about data in time and scale (frequency), wavelet-based coherence allows to measure time-varying correlation as a function of frequency. In other words, a coherence measure suitable for nonstationary processes. Time Frequency analysis is an important tool in modern signal analysis. In this paper, we analyze the relationship between different time series after distributing their energies in both time and frequency domain. Wavelets have the special ability to localize the signal in both time and frequency domain simultaneously. By using this ability, we perform an analytical framework for modeling the statistical behavior of physical parameters of river water such as Width, Velocity and depth. For this purpose, we used ‘cmor1-1’ wavelet of complex Morlet family. Physical parameters of river water are taken from river Ramganga of the time period 2005-2008. CWT of two time series and the cross examination of the two decompositions can reveal localized similarities in time and scale. The magnitude of the wavelet cross spectrum (Wcs) can be interpreted as the absolute value of the local covariance between the two time series in the time-scale plane.