Distributed temperature sensing (DTS) as a measurement method in land surface hydrology and sanitary environmental engineering | Distributed temperature sensing (DTS) als Messverfahren in Landoberflächenhydrologie und Siedlungswasserwirtschaft

In many environmental science disciplines, an understanding of spatiotemporal changes in temperature plays a decisive role in describing systems and their processes. However, the temperature measurements and the values that can be derived from them are generally in-situ point measurements, which are insufficient for describing complex systems and dynamic processes. The distributed-temperature-sensing technique allows high-resolution spatial and temporal temperature measurements and over long distances. An optoelectrical device serves as both light emitter and a spectrometer for measuring the scattering of light along a connected optical fiber. This acts as a linear sensor with a spatial resolution of up to 25 cm. Various applications were tested, with a focus on hydrological issues. By laying an optical fiber along a riverbed, the temperature dynamics in the river, local variations and inflows from the groundwater can be detected. This is useful when it comes to assessing the effects of anthropogenic heat input or determining the influence of shade and river morphological variables on the water temperature and, consequently, the ecosystem. High-resolution snow temperature measurements provide a better understanding of thawing and freezing processes in snow cover, and allow them to be better represented in hydrological models. Heated fiber optic cables can be used to estimate soil moisture content. In addition to hydrological applications, the detection of leaks in lake pressure pipes with a spatial resolution of 25 cm was also tested. In the laboratory, it was possible to detect and locate 6 mm leaks. In all application areas, local temperature changes could be measured accurately, and in turn natural variations, anthropogenic influences and pipeline leaks could be identified.