First results of an extended BROOK90 hydrological model to estimate subdaily water and energy fluxes. A case study of ICOS Anchor station in Tharandt, Germany

We present first results of a new BROOK90 hydrological model version. This new version includes a closed energy and water balance for subdaily time steps based on an adapted Shuttleworth-Wallace model for the description of energy and water fluxes for different evaporation components, like interception, soil evaporation and transpiration. The simulation results have been compared to ICOS eddy-covariance measurements from the Anchor Station Tharandt for the year 2022.

The comparison shows considerable good result for 30-minute estimates of latent and sensible heat fluxes from dry surfaces, whiles simulated fluxes from wet surfaces perform worse. Snow conditions seem to be almost random, but rainy conditions might possess a certain correlation between measured and simulated fluxes. Reason for these results can be found on the one hand in the choice of model parameters for vegetation like maximal canopy resistances, leaf area index or canopy height in the model and on the other hand, limitations of the eddy-covariance measurements under wet conditions.