Continuous Sensing of Water Temperature in a Reservoir with Grid Inversion Method Based on Acoustic Tomography System

Abstract

The continuous sensing of water parameters is of great importance to the study of dynamic processes in the ocean, coastal areas, and inland waters. Conventional fixed-point and ship-based observing systems cannot provide sufficient sampling of rapidly varying processes, especially for small-scale phenomena. Acoustic tomography can achieve the sensing of water parameter variations over time by continuously using sound wave propagation information. A multi-station acoustic tomography experiment was carried out in a reservoir with three sound stations for water temperature observation. Specifically, multi-path propagation sound waves were identified with ray tracing using high-precision topography data obtained with ship-mounted ADCP. A new grid inverse method is proposed in this paper for water temperature profiling along a vertical slice. The progression of water temperature variation in three vertical slices between acoustic stations was mapped by solving an inverse problem. The reliability and adaptability of the grid method developed in this research are verified by comparison with layer-averaged water temperature results. The grid method can be further developed for the 3D mapping of water parameters over time, especially in small-scale water areas, where sufficient multi-path propagation sound waves can be obtained.

Layer-Averaged Water Temperature Sensing in a Lake by Acoustic Tomography with a Focus on the Inversion Stratification Mechanism

“…Based on the results of direct acoustic path travel time and temperature profile [23], the distance between the two stations was calculated. More details and settings have been provided in [21].…”

“…In the process of multi-front identification [21], after two stations are correlated, the peaks with higher SNR were distinguished and identified. The cross-correlation results and multi-peak identifications of S2-S3 during the experiment are stacked in Figure 5.…”

“…The vertical section between two CAT stations is divided into three layers, and the influence of the layer width on the inversion error is analyzed in this study. The detailed experimental process and setting have been introduced by Huang et al [21], and this paper focuses on research concerning the layer method mechanism.…”

Temperature Field Reconstruction Method for Acoustic Tomography Based on Multi-Dictionary Learning

“…Therefore, in order to achieve optimal combustion, as well as safe and efficient operation of the boiler, it is necessary to conduct real-time and accurate monitoring of the temperature distribution inside the boiler [ 1 , 2 , 3 , 4 , 5 ]. The change of atmosphere and ocean has an important impact on the climate and human survival activities, and these changes are also reflected in the change of temperature distribution to a certain extent [ 6 , 7 , 8 , 9 ]. Therefore, the monitoring of temperature distribution in the atmosphere and ocean is not only of great practical significance, but also has broad prospects for development.…”

Flow current field observation with underwater moving acoustic tomography

“…Signal resampling is performed to get correlation of received acoustic data. The vertical layer-averaged flow current results between moving station and moored station are inversed with 2D grid method (Huang et al, 2021;Xu et al, 2021;Xu et al, 2022). 3D flow current field is also reconstructed.…”