Research on simultaneous measurement of ocean temperature and salinity using Brillouin shift and linewidth

The Brillouin backscattered signal of LIDAR can be used in remote sensing of ocean parameters such as temperature. Current methods for measuring ocean temperature are based on the monotropic function between Brillouin shift and ocean temperature, while the effect of the ocean salinity, which influences the measurement of temperature, is neglected. However, the variations in salinity will also lead to nonignorable change of the temperature. Neglecting it will result in an inaccurate measurement of temperature. We first propose a new model that takes both Brillouin shift and linewidth as independent variables, and then establish the multi-valued equations of these variables and ocean parameters. With a data fitting procedure the ocean temperature and salinity can be measured simultaneously. The accuracy of this model and the uncertainty of the measurement are analyzed. Theoretical and experimental analysis showed that the ocean temperature and salinity can be simultaneously obtained by measured Brillouin frequency shift and linewidth. (c) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.OE.51.6.066002]