VARIABILIDAD DEL PARÁMETRO DE RUGOSIDAD SOBRE UNA COBERTURA VEGETAL
Natalia E. Tonti y María Isabel Gassmann
Departamento de Ciencias de la Atmósfera y los Océanos, Buenos Aires, Argentina.
CONICET, Buenos Aires, Argentina
Manuscript received on 9 October 2014, in final form on 1 May 2015
The roughness length is a characteristic scale parameter of the surface layer used in urban pollution, wind potential or micrometeorological studies as well as dynamic models of weather and climate. It is experimentally determined from observational data of the wind profile in neutral conditions. However, there is evidence of dependence with changes in stability. Under the assumptions of the theory of Monin-Obukhov, the variability of the roughness parameter with atmospheric stability was studied from wind profiles observed over a vegetated surface. Empirical expressions for estimating the roughness length variability depending on the stability were obtained. Results showed that in stable condition the roughness length can fluctuate up to two orders of magnitude, whereas in unstable conditions variability was smaller. In addition, the impact of the dependence upon stability of this parameter was studied in a weather processor for contaminant diffusion. The results have a direct impact on the wind field near surface.
Keywords: atmospheric stability, surface layer, wind profile