DFG project “Rainfall interception - Localization of water storage and evapo(transpi)ration in forests”

Rainfall interception is a key component of the water balance. Especially in forests with high plant area density the amount of rainfall interception can sum up to 50 % of gross precipitation. The total amount of rainfall interception can be determined only indirectly by measuring e.g. throughfall, stemflow and gross precipitation. Currently, interception measurements usually provide spatially and temporally averaged values that are only representative for the site but supply no further information about the interception process itself. For example, there is barely a possibility to match evaporation and rainfall interception measurements and thus the parametrisation derived from those measurements is uncertain and cannot be transferred to other sites.

We aim to reduce the existing uncertainties and to provide a robust model parametrisation by connecting high resolution vegetation information from terrestrial laser scans with conceptual interception model approaches. Within the DFG‑Interception project observations of the precipitation components and meteorological data will be performed with high temporal and spatial resolution at the Anchor Station Tharandter Wald (ASTW). The modular 1D model CanWat contains all established conceptual model approaches for rainfall interception and will be used as a basis for model development. The model describes the rainfall interception process of a forest in a matrix of columns with a resolution of 1 m³.

The goal of this project is the development of a 3D model that allows the description of horizontal interactions within the stand. The new 3D model will be checked and validated with the measurements and finally applied to calculate long-term time series of interception loss for the ASTW.