Turbulent structure and local similarity in the tower layer over the Nanjing area

Local similarity of non-dimensional velocity and temperature standard deviations, s sub(T)/T sub(), wind and temperature gradientsh sub(m) and h sub(h) as well as the velocity spectrum is examined using turbulence observations on meteorological towers in Nanjing cityand in its suburb (here subscript i denotes a local value).The empirical constants of similarity functions, whichare dependent on z/L sub(i), are obtained under stable and unstable conditions. Turbulence behaviours at the two sites are compared. Theresults show that the turbulence structure in the tower layer of the atmosphere over either suburb or city could be ordered well by local similarity scales u sub(*i), T sub(*i), L sub(i). The similarity relations of s sub(T)/T sub(*i), h sub(m) and h sub(h) to z/L sub(i) are not sensitive to the underlying surface roughness. However, there are evident differences in the dimensionless velocity standard deviations, and velocity spectra over the urban and the rural surfaces.