ESR1: Airborne and ground-based up-scaling of findings on groundwater-surface water interactions at aquifer-lake and aquifer-stream interfaces
Research Fellow: Amaia Marruedo, Leibnitz Institute of Freshwater Ecology and Inland Fisheries (IGB) (Germany)
Identify drivers of hyporheic exchange flows and quantify exchange across the groundwater-lake interface; Integrate several multi-scale heat tracing technologies to develop a method for characterising the spatially heterogeneous thermal patterns and exchange fluxes at groundwater-surface water interfaces as well as their up- and down-scaling
Tasks and methodology
- Local measurements of hyporheic exchange flows with temperature depth profiles and active heat pulse sensing and identfication of drivers of hyporheic exchange flows (aquifer-stream interface)
- Quantification of groundwater lake exchange by temperature depth profiles, seepage meters, hydraulic gradients
- Upscaling of local findings with FO-DTS and airborne TIR, ground-truthing to verify TIR images
- Quantification of exchange fluxes with model-based up-scaling techniques in close collaboration with ER2 (UoB)
- Joerg Lewandowski, Gunnar Nuetzmann (IGB)
- Co-Supervisor: Stefan Krause (University of Birmingham)
Watch this short video of ER2 Karlie McDonald introducing herself and talking about her Interfaces project:
Scale refers to the spatial or temporal extent at which a process, entity or trend is observed, studied and defined.
Up-Down Scaling is the process by which the data of an observed process, entity or trend at a specific scale, is transferred to an upper or lower scale from the actual observation scale.
Spatial-Temporal variability refers to the changes, deviations or variations in space and time of an observed process, entity or trend.
Hyporheic zone is the transition zone between the ground water and surface water, where biogeochemical processes as well as physical processes take place (e.g. transport, degradation, transformation, precipitation or sorption of substances). The upper boundary of the Hyporheic zone is the stream/lake sediment bed.
Ground water up-welling
Ground water up-welling refers to the process by which groundwater coming from underneath the Hyporheic zone and flowing through it, emerges up to the surface water.
Local-point scale refers to the scale at which the process or entity which is being studied is observed at a spatial dimension ranging from few centimeters, decimeters or even few meters, depending on the researcher´s criteria and object of study.
Plot scale refers to a wider definition of the scale dimension within the study, ranging from few meters to several meters, depending on researcher´s criteria, where the processes or entities studied are influenced by more variables and processes that at local/point scale; due to the wider spatial extent considered which includes or covers more environmental variables and processes.
Reach scale might be defined as the spatial extension or dimension considered in a study which ranges from several meters up to 100 meters, depending on the researcher´s criteria and the object of study. As mentioned in the Plot Scale definition, the number of influencing variables and processes considered within this scale should be higher than local/point and plot scale; due to the broader spatial dimensions considered.
FO-DTS fiber optical distributed temperature sensor allows the measurement of surface waters´ temperature at stream or lake bed, as well as within the water column of a water body between other functions. By timing the time needed to return by the light sent from the laser device through the fiber optic cable, the distance at which the light was reflected can be derived. On the one hand, one part of the laser pulse sent through the fiber optic cable is reflected back to the device with the same wavelength. On the other hand, the other part of the energy pulse will be absorbed and reemitted with shorter and longer wavelengths. By the ratio of both shorter/longer wavelengths it is possible to derive temperature values along the cable.
Remote Sensing is the science which allows obtaining information of objects or areas from a distance. For instance, by satellites, aircraft, UAV or hand-held devices in order to describe or characterize processes or entities observed within the environment
UAV unnamed aerial vehicle also called “drone” is an aircraft without a human pilot onboard. The flight can be controlled autonomously by onboard computers or by the remote control of a pilot on the ground.
Thermal infrared radiation (TIR) or energy
Thermal infrared radiation (TIR) or energy, which could be referred to as “heat”, comprises the electromagnetic waves with a wavelength of between 3.5 and 20 micrometers. The thermal radiation is emitted from a body, in our case a water body. From the emitted radiation of the water body, temperature information of the water surface can be derived.