10A.2 Reasons for the breakdown of Monin-Obukhov similarity theory above rough surfaces

Wednesday, 11 June 2008: 10:45 AM
Aula Magna Vänster (Aula Magna)
Jan H. Schween, University of Cologne, Cologne, NRW, Germany

Since Thome (1971) it is known that abouve rough surfaces gradients are

smaller than predicted by Monin-Obkhov similarity theory (MO-theory). In 1989 Raupach

proposed with the localized near field theory (LNF) a lagrangian approach to model

source distributions in plant canopies. This theory can be used to derive a

general formulation for profiles within and above plant canopies. Comparing

such profiles with profiles predicted by MO-theory gives insight into the

mechanisms leading to the deviation from MO-theory. These are mainly the

enhacement of turbulence which reduces gradients and the near field effects

in turbulence which enhance gradients.

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