Abstract. Highly distributed temperature data are used as input and as calibration data for a temperature model of a first order stream in Luxembourg. A DTS (Distributed Temperature Sensing) fiber optic cable with a length of 1500 m is used to measure stream water temperature with a spatial resolution of 0.5 m and a temporal resolution of 2 min. With the observations four groundwater inflows are found and quantified (both temperature and relative discharge). They are used as input for the distributed temperature model presented here. The model calculates the total energy balance including solar radiation (with shading effects), longwave radiation, latent heat, sensible heat and river bed conduction. The simulated temperature along the whole stream is compared with the measured temperature at all points along the stream. It shows that proper knowledge of the lateral inflow is crucial to simulate the temperature distribution along the stream, and, the other way around stream temperature can be used successfully to identify runoff components. The DTS fiber optic is an excellent tool to provide this knowledge.
An unconditionally stable semi-analytical Lagrangian stream temperature model
