Test of a modified Shuttleworth-Wallace estimate of boreal forest evaporation

A modified version of the two-layer Shuttleworth-Wallace approach was used to simulate evaporation from a mixed 50-100 years oldboreal forest stand in central Sweden. It was tested against eddy correlation flux measurements f rom the Northern hemisphere climate Processes land-surface Experiment (NOPE X). The soil regulation on canopy resistance was taken into account when es timating transpiration. The generality of the model performance was attaine d by using model parameters that represented typical boreal forest stand an d not the specific stands at the site. The analysis was done for two growin g seasons, 1994 and 1995 having quite different weather conditions. Despite the rough parameterisation, the model performance was good. Problems regar ding representativity of the measured data used for the model validation ar e discussed. It was concluded that the model could accurately simulate evap oration components on a seasonal time scale and is suitable to he incorpora ted as a submodel in larger forest ecosystem models. (C) 1999 Elsevier Scie nce B.V. All rights reserved.