The Distributed Temperature Sensor measures different variables along a fiber optic cable. The sensor is composed of two parts where the first is the device that sends a light signal into the fiber optic cable and receives the reflection generated by the rayleigh scattering as the light travels through the fiber optic cable and the second part is the fiber optic cable. If the light is traveling through a fiber optic cable it is being reflected at every point inside the cable. These reflections will travel in the opposite direction as compared to the main direction of the light. These reflections are received by a highly sensitive receiver present at the starting point of the fiber optic cable and measure the temperature.
The location Hobrechtsfelde was formerly a Rieselfeld (sewage field). The location consists of 14 wells that are 1-2 meters apart from one another. These wells serve as the hosts for high-resolution pressure and temperature monitoring equipment and are dispersed over a 3-D subsurface area. The location is suited for thermo-tracer tomography experiments and hydraulic tomography studies in three dimensions, and it can host dispersed temperature monitoring systems. To confirm the various hydraulic conditions, a portion of the wells is filtered in an upper, unconfined aquifer and the other portion in a lower, confined aquifer.
East of Berlin, the Rüdersdorf field site is primarily a limestone quarry. It is the key pilot site in GRaCCE for developing using hydrogeophysical techniques to measure and monitor infiltration into the vadose zone with the TDR technique. Therefore, we plan to create several vertical and slanted boreholes at the field site, which will be equipped with TDR bands and fiber optic cables down to a depth of 30m.