Estimation of the zero-plan displacement, roughness length and aerodynamic resistance to water vapour exchange for a corn canopy for conditions of near neutral stability.

Abstract

Zero-plane displacement, roughness length and aerodynamic resistance to water vapour exchange for conditions of near neutral stability were determined, using different profiles of wind speed above a corn canopy with a mean height of 2.80 m, during the tasselling period. The results showed a decrease for the roughness length and a increase in the zero-plane displacement with an increase of the wind speed between the intervals of 0.2 and 3.5 m s-1. In this condition the mean estimated value for the aerodynamic resistance to water vapour exchange was 0.19 s cm-1, very low if compared to the others.