Surface layer turbulence spectra and dissipation rates during low winds in tropics |
| |
Authors: | Anil Kumar Yadav Sethu Raman Maithili Sharan |
| |
Institution: | (1) Centre for Atmospheric Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India;(2) Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, 27695-8208 Raleigh, NC, USA |
| |
Abstract: | Spectral characteristics of surface layer turbulence in an urban atmosphere are investigated. The observations used for this purpose represent low wind conditions in the tropics. The normalized power spectral shapes exhibit the usual characteristics in the inertial subrange and obey Monin-Obukhov scaling. However, the low-frequency behaviours do not conform to the previous observed relations. For horizontal components, large energy is contained in the low frequencies in contrast to the vertical component where roll-off to zero frequency is faster.The turbulent kinetic energy dissipation rate estimated from the spectra using Kolmogorov's inertial subrange law is found to be isotropic unlike the velocity variances. The expressions for the dimensionless dissipation rate do not seem to work well in low winds in an urban atmosphere. For the data considered, the dissipation rate exhibits a power law relationship with the mean windspeed and the friction velocity. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|