Test of a forest evapotranspiration model.

Typ: Rapport
Serie: RMK 52
Författare: Bringfelt, Björn


The model computes daily forest evapotranspiration using routine weather observations. The model was developed from detailed meteorological and evapotranspiration measurements in a forest in the Velen hydrological research area in southern Sweden.
The model was tested successfully against independent monthly evapotranspiration from the Velen area obtained by the water balance method. In this report the model is improved based on this comparison and the new model is tested against water balance data from two other hydrological research areas, Kassjöån and Lappträsket in middle and north Sweden.
Model comparisons have been made for the Jädraås forest in middle Sweden where detailed meteorologicaI and evapotranspiration measurements have also been made. The model now has a parameter set for each of the forest stands in Velen and Jädraås.
The model can interrelate various data such as routine weather data, hydrological data, rainfall interception and meteorological mast data. This may imply a better utilization of different data sets.
It has been shown that knowledge of water losses from a forest can be used to estimate dry deposition of gaseous pollutants such as sulfur dioxide. In a new study the model will be used to estimate dry deposition of sulfur dioxide to the forests of Velen and Jädraås continuously during one year.