Inversion of seawater temperature, salinity, and sound velocity based on Brillouin lidar

In this study, a two-parameter inversion model is used to improve the accuracy of seawater temperature and salinity inversion. Furthermore, a novel model is proposed to invert the seawater sound velocity, using Brillouin frequency shift and linewidth as independent variables to establish their relationship with the sound velocity. The temperature, salinity, and depth data of the East China Sea collected from the World Ocean Atlas 2018 were used to simulate the seawater sound velocity in the range of 0-100 m at different longitudes and latitudes in different seasons. The results indicate that the simultaneous inversion of the three parameters can be realized using the Brillouin frequency shift and linewidth. The maximum errors of the temperature, salinity, and sound velocity for the inversion model were 0.079 degrees C, 0.122 parts per thousand, and 0.124 m/s, with relative errors of 0.212, 0.156, and 0.015%, respectively.