Surface resistance calibration for a hydrological model using evapotranspiration retrieved from remote sensing data in Nahe catchment forest area

Abstract

In this paper, a method combining graphical and statistical techniques is proposed for surface resistance calibration in a distributed hydrological model, WaSiM-ETH, by comparing daily evapotranspiration simulated by model WaSiM-ETH with corresponding daily evapotranspiration retrieved from remote sensing images. The study area locates in Nahe catchment (Rhineland-Palatinate, Germany, 4065 km 2 ) forest regions. The remote sensing based observations are available for a very limited number of days but representative for most soil moisture conditions. By setting canopy resistance (rc) at 150 s/m, soil surface resistance (rse) at 250 s/m or at 300 s/m for deciduous forest and setting rc at 300 s/m, rse at 600 s/m or at 650 s/m for pine forest, the model exhibits its best overall performance in space and time. It is also found that with sufficient soil moisture, the model exhibits its best performance in space scale.

Finding behavioral parameterization for a 1-D water balance model by multi-criteria evaluation

“…Therefore, soil parameteri-zation, and especially the representation of the Water Retention Curve -as one of the most important soil-physical characteristics -strongly influence the simulation of evapotranspiration. A similar effect can be observed when canopy resistances are wrongly estimated (Bie et al, 2015). In order to find an appropriate model parametrization, we have to verify that the model realistically reproduces both, the temporal patterns of soil moisture and evapotranspiration.…”

“…(Schulla, 2017). The WaSiM-ETH model has performed well in sub-alpine and alpine catchments (Cullmann et al, 2006;Gurtz et al, 2003;Jasper, 2001;Jasper et al, 2002;Klok et al, 2001;, also in middle-mountain (Bie et al, 2015;Grigoryan et al, 2010;Middelkoop et al, 2001), and lowland catchments (Elfert and Bormann, 2010). The model is documented in both English and German and can be used free of cost (http://www.wasim.ch).…”

“…There are default values of bulk surface resistance parameters in WaSiM-ETH. The maximum amount of canopy surface resistance rsc is in November to February, whereas in May to September, it reduces to its annual lowest level (Bie et al, 2015;Schulla, 2017). The soil surface resistance rse remains constant for the entire year.…”