Hydrological profile observation scheme based on optical fiber sensing for polar sea ice buoy monitoring

Abstract

The monitoring of hydrological elements in the polar region is the basis for the study of the dynamic environment under the ice. The traditional cross-season subglacial hydrological environment monitoring mainly relies on tether-type vertical profile measurement ice-based buoys, which have the advantages such as high reliability, high measurement accuracy, and real-time communication, while also has disadvantages of high-cost, large volume and weight, high power consumption, and complex layout. Therefore, it is urgent to develop a new type of ice-based profile buoy with low-cost, miniaturization, low power consumption, convenient deployment, and high reliability. In this paper, a novel optical fiber sensing scheme for ice-based buoy monitoring is proposed, which uses arrayed fiber grating to measure seawater temperature and depth profile and uses a dual-conduction mode resonance mechanism to measure seawater salinity. The temperature, depth, and salinity of seawater can be detected by an all-optical fiber technology in real-time. Preliminary experiments show that the temperature accuracy is ±0.1 °C in the range of -5∼35 °C, the salinity accuracy is ±0.03‰ in the range of 30‰∼40‰, and the vertical spatial resolution of depth can be adjusted in the range of 0∼1000 m, which can better meet the requirements of polar hydrological multi-layer profile observation. It can provide an innovative technology and equipment support for studying the spatiotemporal change process of the polar subglacial ocean.