The Spatial Structure of Turbulence in the Atmospheric Boundary Layer

An account is given of the statistical structure of turbulence in the natural wind near the ground (i.e. below about 100 m in height). Wind data measured at a single point are briefly reviewed, followed by a discussion of the statistical concepts needed to describe spatial structure (i.e. behaviour when concurrent data at more than one point are involved). The theoretical ideas are interpreted in terms of typical eddy structures, and a review is given (without any claims to being exhaustive) of available observational data on important turbulence parameters, concentrating particularly on scarce two-point (spatial structure) data. Emphasis is given to time domain (rather than frequency domain) statistics, and some mention is made of the wind turbine applications which motivated the study.