Monin-Obukhov similarity theory

Monin-Obukhov similarity theory, as expressed by (7.10), can be used in (9.2) to give... 

Monin-Obukhov similarity theory can be used to prescribe the form of Ka in the surface layer. can be expressed as... 

Under neutral conditions the atmospheric lapse rate is adiabatic. Close to the ground the vertical eddy diffusivity profile can be based on Monin-Obukhov similarity theory, in which case = 1 and = ku,z- With this formulation, increases without limit—clearly a physically unrealistic situation. Myrup and Ranzieri (1976) proposed a set of empirical roll off functions for altitudes above the surface layer ... 

The first strategy implies the direct use of physical parameters estimated by MetMs, like e.g. Monin-Obukhov similarity theory (MOST) parameters, and limitation of the interface module tasks to the evaluation of missing variables. This approach... 

The calculation of the resistance coefficients can be accomplished in the frame of the Monin-Obukhov similarity theory (Monin and Yaglom, 1971). The genuine flux quantities are the friction velocity u and the scale functions 0 and referring to temperature and humidity. The turbulent momentum flux f, the sensible heat flux the mass flux from evaporation and condensation and the corresponding latent heat flux are... 

The basic logarithmic velocity profile (16.66) is applicable only to adiabatic conditions. However, the atmosphere is seldom adiabatic, and the velocity profiles for stable and unstable conditions deviate from this logarithmic law. For the more frequently encountered nonadiabatic atmosphere (also called stratified), the Monin-Obukhov similarity theory is usually employed (Monin and Obukhov 1954). 

The expressions available for Kzz are based on Monin-Obukhov similarity theory coupled with observational or computationally generated data. It is best to organize the expressions according to the type of stability. 

In the surface layer over homogeneous terrain, so-called surface-layer (or Monin-Obukhov) similarity theory can be used to study the combined effects of convective and mechanical turbulence on the profiles and distributions of mean and turbulence characteristics. For instance, if at r variable with the dimensions of velocity is normahzed by the friction velocity m+o, the resultant dimensionless qirantity then only depends on z/Z. As an example of the application of this type of similarity or scaling, consider the standard deviation of vertical velocity Surface-layer similarity theory requires... 

In the forced convection layer, wind shear plays a dominant role, and the Monin-Obukhov similarity l pothe-sis applies. To develop their similarity theory Monin and Obirkhov idealized the field of motion that is frequently used in the atmosphere near the ground. It was assumed that all statistical properties of the temperature and velocity fields are homogenous and do not vary with time. The steady mean motion was considered to be unidirectional at all heights in the x-direction. Second-order terms in the equations of the field were considered to be negligible. The scale of motion was considered to be small enough to omit the Coriolis Force, and the radiative heat inflow was neglected. In the surface layer the turbulent fluxes are approximately constant at their smface values. 

Because both mechanical and convective forces determine turbulence, Monin and Obukhov proposed a similarity theory that introduced two scaling parameters, the friction velocity and the length L, where... 

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