Resolving Spectral Signatures of Physical Properties in an Estuary

Marc Di Ciccio, Gary Zarillo, and P. G. Robert Weaver

Florida Institute of Technology, USA

Abstract: Analysis of time-series data from the frequency-domain can help elucidate the influence of physical properties, such as wind, water level, and barometric pressure, on the movement of water in an estuary. This paper describes acoustic doppler current profiler data collected from three stations in the Banana River Estuary located in the north compartment of the Indian River Lagoon in Cape Canaveral, Florida. The relevant data include water level, current velocity, and current direction, which are processed, subject to quality control, and then transformed using a discrete Fourier-transform to obtain the frequency spectra. The resulting frequency spectra indicate prevalent signatures which can then be isolated using digital filters. Narrow stopband finite-impulse-response filters are designed using the Parks-McClellan algorithm to extract signatures associated with physical properties of which time-series data are available. The filtered data are then used to estimate the contribution of each physical property to the current velocity time series, as well as to graphically estimate the correlation between the amplitude of the time-domain data stored in those frequencies.