Method and system for measuring seawater temperature

Abstract

The invention discloses a seawater temperature measuring method and a seawater temperature measuring system, and relates to the sea temperature remote sensing technology field. The seawater temperature measuring method comprises steps that laser is divided into coherent local oscillator light and probe light, and the probe light is focused in a water area at a specific depth; backward Rayleigh Brillouin scattering light is received from the water area at a specific depth; the frequency mixing of the backward Rayleigh Brillouin scattering light and the local oscillator light is carried out, and after photoelectric conversion, an intermediate frequency signal is output; Brillouin frequency shift is extracted from the intermediate frequency signal, and according to a seawater temperature inversion model, the temperature of the seawater at the specific depth is acquired. The Brillouin frequency shift and underwater vertical temperature distribution are acquired in a fast and high-precision way, and therefore costs are low, measurement is convenient, real-time performance is good, and anti-noise performance is good.

Description

technical field [0001] The invention relates to the technical field of ocean temperature remote sensing, in particular to a seawater temperature measurement method and system. Background technique [0002] Brillouin scattering is an inelastic scattering in which photons interact with a medium. When Brillouin scattering occurs, a photon will annex a phonon to increase its own energy through collision, or lose its own energy to generate a phonon. The exchange of acousto-optic energy generated by this collision will cause a change in the frequency of the scattered light. In the frequency spectrum, this light frequency change is reflected in the fact that the Brillouin scattering peaks are divided into Stokes peaks and anti-Stokes peaks, and their positions are symmetrically distributed on both sides of the laser center frequency, and relative to the laser center There is a certain shift in frequency. This shift is named the Brillouin shift. The spectral distribution of Brill...

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Problems solved by technology

[0003] In the application of ocean temperature remote sensing, the Brillouin scattering spectroscopy measurement technology adopted by the Brillouin scattering-based lidar system mainly falls into the following two categories: edge detection technology and F-P Fabry-Pérot scanning interferometer technology, among them, the cost of edge detection technology is higher, and the scanning time of F-P scanning interferometer is longer, both of these technologies are limited in practical application

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