Using Wavelet Analysis to Assess the Relationship of Hydrological and Hydrooptical Oscillations in the Range of Internal Waves According to in situ Observations in the White Sea

Zhegulin G. V.

The aim of the study is to develop a methodology of combined statistical analysis of spatial and temporal variability of hydrological and hydrooptical observations data and their synchronization rate using the wavelet analysis. The technique of the wavelet analysis allows to identify non-stationary fluctuations in the studied signal associated with local transient processes in the water column. The wavelet transform provides a two-dimensional scan of one-dimensional implementation, the frequency and time are considered as the independent variables. This gives the opportunity to analyze many things in physical and spectral space. On the basis of experimental data obtained during the expedition in August 2013 in the White Sea on the boundary of the Basin and the Strait Western Solovetsky Salma, a joint statistical analysis of spatial and temporal variability of temperature and indicator light attenuation in the layer jump based on wavelet transform is done. The basic energy-scale fluctuations in the range of 1.5—3 h and 5—8 h are indicated. High coherence between the vertical displacement of the thermocline according to temperature and light attenuation index is revealed in these bands. An increase in the attenuation takes place with a lag phase of temperature by 3—4 h within the scope of oscillations 5—8 h and at 0.5—1 h, in the range of 1.5—3 h. Fluctuations in these ranges can be identified as internal waves and be registered by optical means. As a result of researches it is revealed that for the space-time diagnosis and evaluation of the contribution of fluctuations of the temperature field as an indicator of internal unrest in the variability of hydrooptical characteristics, it is preferable to make the analysis of signals based on time series of vertical displacements of these characteristics, because the distribution of the spectral estimates on depths only provides a general information about the state of the oscillating system.

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