چکیده (انگلیسی):

The accurate measurement of sap flow is important for estimating transpiration. This paper is focused on the errors in sap flux density (J) caused by probe misalignment and on how to reduce these errors. We found that probe misalignment caused errors in the heat pulse velocity (Vh). Furthermore, probe misalignment had a large influence on thermal diffusivity (κ) and the determination of zero flow points. Assuming uniform axial thermal diffusivity and zero sap flow conditions, we developed a new in situ probe spacing correction method based on three temperature sensor measurements inside the same temperature probe, which can be used for correcting both linear and nonlinear misalignments. Laboratory experimental results verified that our method could significantly reduce the errors in determinations of J by using the Compensation Heat Pulse velocity (CHP) method, the Heat Ratio (HR) method and the T-max method.