硝酸盐传感器在深海压力下的校准方法  

Correction of pressure effect in calibrating nitrate concentration of seawater

作　　者：张乃心 朱星玥 单保一 徐鉴 吴锜 Zhang Naixin;Zhu Xingyue;Shan Baoyi;Xu Jian;Wu Qi(Institute of Marine Science and Technology,Shandong University,Qingdao 266237,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China;School of Science,The Hong Kong University of Science and Technology,Hong Kong 999077,China)

机构地区：[1]山东大学海洋研究院,山东青岛266237 [2]南方海洋科学与工程广东省实验室(广州),广东广州511458 [3]香港科技大学理学院,中国香港999077

出　　处：《红外与激光工程》2024年第3期280-283,共4页Infrared and Laser Engineering

基　　金：南方海洋科学与工程广东省实验室(广州)基金项目(GML2021GD0808)。

摘　　要：研究表明,海水中溴化物的紫外吸收光谱受到深海压力的影响会影响海水中硝酸盐的测量准确度。现有的水下硝酸盐传感器已暴露出测量误差大,环境适应性差、无法应用于2000 m以下的深海探测等问题。因此,为了更准确地计算硝酸盐浓度,有必要开展深海压力对海水紫外吸收光谱的校正研究。实验室对模拟深海压力环境中的硝酸盐进行测试试验,提出了两种算法用来矫正压力下的紫外光谱,通过实验验证了这两种压力校正算法对硝酸盐计算的预测准确性。结果表明,多元散射校正-偏最小二乘法回归校正算法具有最好的测量效果,R^(2)为0.997,平均绝对误差(MAE)为1.294μmol/L,平均偏差误差(MBE)为0.037μmol/L。Objective Optical nitrate sensors have advantages for in-situ exploration and the potential for long-term observation in deep-sea environment.However,measurement of optical nitrate is influenced by substrates in seawater,especially bromide ions(Br-),within the relevant spectral range,causing a spectral shift in the ultraviolet(UV)intensity spectrum.In recent years,the pressure coefficient of the UV absorption spectrum of bromine under seawater pressure of 2000 meters has been studied and experimentally confirmed,that the bromide in seawater affects the UV absorption spectrum.Considering that the seabed minerals are primarily distributed undersea at depths ranging from 1000 to 6000 meters,achieving accurate in-situ detection of nitrate concentration becomes crucial for the assessment of impact of seabed mining on the marine eco-system,establishment of an early warning system for the marine mining environment.Currently,products of nitrate sensors are limited to the submerged depths of approximately 2000 meters.No nitrate sensor product is available beyond this depth.This paper reports a calibration method for nitrate measurements within the pressure range of 0-50 MPa(0-5000 meters),aiming to improve the accuracy of nitrate measurements in deep-sea environments.Methods A system capable of measuring the UV spectrum of seawater under deep-sea pressure is constructed in this work.The light emitted from a deuterium lamp is transmitted through a fiber-optic beam splitter,dividing it into two paths.One path passes through a fiber-optic attenuator,while the other path goes through a pressure vessel.The two signals are then combined at an optical switch and selectively transmitted through it.Finally,the data processing module performs data acquisition and calculation.To simulate the deep-sea environment,the pressure vessel is connected to a weight manometer.The UV absorption spectra at different pressure are measured by controlling the external pressure.A continuous flow analyser was used to calibrate the nitrate concentrat

关 键 词：硝酸盐 压力校正 紫外光谱法 多元散射校正 

分 类 号：O433.4[机械工程—光学工程]