Investigation of short-scale sea wave spectra with optical and radiometric methods

Abstract

In paper presents a comparative study of the short-scale wind waves spectra, received by means of optical and radiometric methods. The optical method for recording the wind waves spectrum is based on spectral analysis of the optical images of the sea surface with non-nadir observations. An incoherent optical spectrum analyzer developed at the Institute of Applied Physics of the Russian Academy of Sciences is described that allows one to record two-dimensional spectra of the sea surface in real time in the wave number range from 0.3 to 5.0 rad/cm. Wind-wave spectrum retrieval using microwave radiometers was carried out by the method of Non-linear Radiothermal Resonance Spectroscopy (NRRS), which was developed and are improving at present at the Space Research Institute of the Russian Academy of Sciences. Using a set of radiometers-polarimeters of the 3, 5 and 8-mm ranges, provides restoration of the spectrum in the range of wave numbers from 0.39 to 15.0 rad/cm. Synchronous microwave and optical measurements of wind wave spectra were carried out on a marine hydrophysical platform in the Black Sea. The results of the sea wave's spectrum restoration obtained by means microwave and optical technique gave almost identical estimates of the spectral curves level, which also coincide with the model spectra. This fact confirms the consistency of described wind wave's spectra recording methods and the possibility of their use for monitoring the sea surface state in natural conditions.