Premium
Distinct Turbulence Structures in Stably Stratified Boundary Layers With Weak and Strong Surface Shear
Author(s) -
Lan Changxing,
Liu Heping,
Li Dan,
Katul Gabriel G.,
Finn Dennis
Publication year - 2018
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2018jd028628
Subject(s) - eddy , turbulence , mechanics , planetary boundary layer , boundary layer , geology , physics , meteorology , momentum (technical analysis) , atmospheric sciences , finance , economics
Turbulence structures and exchange of momentum and heat in the nocturnal stable boundary layer (SBL) show distinct features under different stability conditions prompting interest in their connection. Here eddy covariance data collected at four different heights on a 62‐m meteorological tower over a large open flat terrain are used to characterize different SBL states and associated turbulence structures. In a SBL characterized by strong near‐surface winds, turbulent eddy sizes scale with their observational heights and the SBL experiences enhanced turbulent mixing of momentum and heat throughout (a state hereafter referred to as a “coupled” state). Conversely, in a decoupled SBL, weak winds occur near the surface and turbulent eddies are depressed and detached from the boundary leading to suppressed vertical mixing and layered SBL profiles. Because the transport of momentum and heat to the surface across SBL layers is determined by turbulent eddies, cross‐layer correlation and the aforementioned SBL coupling states can be delineated by distinct turbulence structures.