Analysis of frequency content of temperature glider data via Fourier and wavelet transforms

A methodology to analyze the spectral content of glider data is proposed by showing the application to time series taken during missions in the Mediterranean Sea. Three missions have been investigated, two in the Tyrrhenian Sea and one south of Cyprus. Fluctuations appearing in temperature series recorded by gliders are studied with the help of the Fourier and wavelet transforms. The Fourier transform has been used to localize high energy in a certain range of frequencies, which is limited by the experimental setting or sampling rate. The obtained information together with additional analysis via the wavelet transform provide a way to localize these features in time and in space, allowing a better understanding of their nature and physical meaning.