x / Transporte turbulento na camada superficial da atmosfera em condicoes diabaticas

AUTOR(ES)
DATA DE PUBLICAÇÃO

1980

RESUMO

An expression for the diabatic wind profile is derived by various workers using dimensional analysis and the assumption that the turbulent diffusivity coefficient for momentum can be partitioned into two parts, one associated with forced convection and the other with natural convection. The turbulent diffusivity coefficient is also assumed to be given as a linear combination of the diffusivity coefficient due to forced and that due to free convection. This assumption is in contrast with the assumption of the quadratic combination of the diffusivity coefficients which, according to Sellers, leads to the equation for the wind profile derived by Ellison, Yamamoto, Panofsky et al. Then, a new modified KEYPS equation is suggested by Yamamoto and Shimanuki. This modified equation is solved approximately, resulting rational expressions for the wind shear, which lead to results that compare favorably with the observed data. However, the nondimensional temperature profiles showed some systematic deviation from the measured profiles. Nondimensional fluxes of heat and momentum are calculated using the shear functions. Nomograms relating stability parameter ?(?), dimensionless height ? and function ?? are presented for a specific case. The ratio of the turbulent sivity coefficients for heat and momentum is evaluated in different atmospheric stratification conditions. This ratio is approximately equal to 1, 35 in neutral conditions; it decreases slowly to unity in stable conditions, and shows a marked increase with instability.

ASSUNTO(S)

perfis de vento escala de turbulencia micrometeorologia camada limite micrometeorology

ACESSO AO ARTIGO

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