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Review of atmospheric turbulence over cities
Author(s) -
Roth M.
Publication year - 2000
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712656409
Subject(s) - turbulence , bluff , urban climatology , boundary layer , meteorology , planetary boundary layer , environmental science , wake , mixing (physics) , flow (mathematics) , plane (geometry) , atmospheric sciences , mechanics , geology , physics , mathematics , urban climate , urban planning , geometry , engineering , civil engineering , quantum mechanics
This paper provides a comprehensive, critical review of turbulence observations over cities. More than fifty studies are analysed with their experimental conditions summarized in an appendix. The main results are based on 14 high‐quality experiments which met criteria based on stringent experimental requirements. The observations are presented as non‐dimensional statistics to facilitate comparison between urban studies and work conducted over other rough, inhomogeneous surfaces. Wake production associated with bluff bodies, and the inhomogeneous distribution of sources and sinks of scalars, result in a roughness sub‐layer which for the studies reviewed extends to about 2.5 to 3 times the height of the buildings. It is shown that within this region the basis of several traditional micrometeorological approaches to describe the turbulent exchange is in doubt. There are strong similarities to flow over plant canopies, and many of the turbulence characteristics can be interpreted in the framework of a plane mixing layer. Future field observations should concentrate on the turbulent exchange near the top and within the urban canopy as well as within the urban boundary layer.