IMPROVING THE DIAGNOSTIC RELATION FOR THE NOCTURNAL BOUNDARY-LAYER HEIGHT

A one-dimensional model of the nocturnal boundary layer (NBL) has been used to investigate the time variation of the NBL height for stationary and horizontally homogeneous synoptic conditions. The time variation of the well known quantity γ = hflu* has been shown to be related to the wind variation at the top of the NBL. For the simple simulated conditions, this variation depends only on the roughness length and the Coriolis parameter. The value of γ averaged over the whole night is a function of the friction velocity. An expression is proposed for γ which is compared with observations. Under stationary external conditions, the new relation improves the determination of the NBL height if compared with the classical relation using a constant value of γ. © 1990 Kluwer Academic Publishers.