Open AccessTemporal and Spatial Aspects of Velocity Variance in the Urban Surface Roughness Layer
Author(s) -
B. B. Hicks,
Eleovakovskaia,
R. Dobosy,
William R. Pendergrass,
William J. Callahan
Publication year - 2013
Publication title -
journal of applied meteorology and climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.079
H-Index - 134
eISSN - 1558-8432
pISSN - 1558-8424
DOI - 10.1175/jamc-d-11-0266.1
Subject(s) - variance (accounting) , wind speed , similarity (geometry) , surface finish , surface roughness , environmental science , surface layer , surface (topology) , roughness length , atmospheric sciences , meteorology , layer (electronics) , mathematics , statistics , geology , geometry , geography , physics , materials science , wind profile power law , computer science , thermodynamics , economics , accounting , composite material , artificial intelligence , image (mathematics)
Data from six urban areas in a nationwide network of sites within the surface roughness layer are examined. It is found that the average velocity variances in time, derived by averaging the conventional variances from a network of n stations, are nearly equal to the velocity variances in space, derived as the variances among the n average velocities. This similarity is modified during sunlit hours, when convection appears to elevate the former. The data show little dependence of the ratio of these two variances on wind speed. It is concluded that the average state of the surface roughness layer in urban and suburban areas like those considered here tends toward an approximate equality of these two measures of variance, much as has been observed elsewhere for the case of forests.