标题：Optimal design of optical refractometer for seawater salinity measurement
作者：Cen, Xia; Su, Juan; Li, Guoqiang; Wei, Wei; Bai, Xiaoxue; Wu, Chi
作者机构：[Cen, Xia; Su, Juan; Li, Guoqiang; Wei, Wei; Bai, Xiaoxue; Wu, Chi] Shandong Univ, Inst Marine Sci & Technol, Marine Sensors Res Ctr, Jinan, Peoples R 更多
会议名称：2nd Target Recognition and Artificial Intelligence Summit Forum
会议日期：AUG 28-30, 2019
来源：SECOND TARGET RECOGNITION AND ARTIFICIAL INTELLIGENCE SUMMIT FORUM
关键词：optical refractive index; seawater salinity; optical refractometer;; v-block
摘要：Salinity of seawater is one of the most important ocean parameters. Salinity of seawater is mainly obtained by conductivity measurement using CTD (Conductivity-Temperature-Depth). Conversion accuracy between conductivity and salinity relies on the assumption that components of seawater are fixed, as well as high accuracy and synchronism measurements of conductivity, temperature and pressure. The study of seawater salinity based on the V-block optical refractive index method provides a total different principle for salinity measurement. Achieving high resolution seawater optical refractive index measurements could help to study factors affecting the accuracy of salinity measurement. In this paper, the various instrument parameters that affect the accuracy of seawater refractive index measurement are analyzed and the optical refractometer is optimized based on the components on the shelf. This paper systematically analyzed the resolution and tolerance of refractive index measurement on the parameters of V-block refractometer, such as incident angle, external environment and prism refractive index, etc. The optical refractometer with an air film layer on both sides of the V- block was proposed for seawater salinity measurement. With such an optimization, the measurement accuracy is further improved and the tolerance is increased. The theoretical resolution to the seawater refractive index and salinity are 1.8x10(-6) and 0.01 parts per thousand, respectively. Experimentally, we have achieved 3.9x10(-6) and 0.021 parts per thousand respectively, and a good linearity. The difference between theoretical and experimental results are analyzed.