Velocity derivatives in the atmospheric surface layer at Reλ=104

We report first results of an experiment in which explicit information is obtained on the field of velocity derivatives (all the nine components of the tensor ∂ui/∂xj) along with all the three components of velocity fluctuations at Reynolds number as high as Reλ∼104. This includes information on such basic processes as enstrophy and strain production, geometrical statistics, the role of concentrated vorticity and strain, and the reduction of nonlinearity.