DOI: 10.1029/2017JD028195
Scopus记录号: 2-s2.0-85046137634
论文题名: Enhanced Temperature-Humidity Similarity Caused by Entrainment Processes With Increased Wind Shear
作者: Gao Z. ; Liu H. ; Li D. ; Katul G.G. ; Blanken P.D.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2018
卷: 123, 期: 8 起始页码: 4110
结束页码: 4121
语种: 英语
英文关键词: air-lake interaction
; eddy covariance
; entrainment processes
; large eddies
Scopus关键词: air temperature
; air-water interaction
; boundary layer
; correlation
; eddy covariance
; entrainment
; humidity
; large eddy simulation
; spectral analysis
; wind shear
英文摘要: A number of studies already suggested that entrainment of warm/dry air from aloft degrades the similarity between air temperature (T) and specific humidity (q) in the atmospheric surface layer (ASL). Less is known about entrainment of cool/dry air on the ASL T-q similarity. Using eddy covariance measurements over a large inland water surface, enhanced T-q similarity with increased friction velocity (u*) was measured during daytime unstable conditions. Explaining this enhancement is the main goal of this work. Cool/dry air masses originating and advecting from land set the upper boundary condition on a quasi-equilibrated internal boundary layer embedding the warm/moist ASL over water. With increased u*, the entrainment velocity (dhI/dt ∝ u*) increases, thereby enhancing entrainment of cool/dry air originating from land, where t is time and hI is the internal boundary layer depth. By analyzing the scale-dependent (spectral) correlation coefficients, the enhanced T-q similarity with increased u* was shown to originate from spectral correlation coefficients in the middle- to low-frequency ranges (large eddies ≫ z, the distance from the surface). With further increases in u*, similarity between T and q within large eddies was further enhanced and phase differences between T and q was reduced. Quadrant analysis showed large increases in flux and time fractions of downward large cool/dry eddies with increasing u*. These results provide evidence that enhanced entrainment of synchronized, large cool/dry eddies was a primary cause for the increased T-q similarity with increasing u*. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114067
Appears in Collections: 气候减缓与适应
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作者单位: Laboratory for Atmospheric Research, Department of Civil and Environmental Engineering, Washington State University, Pullman, WA, United States; Department of Earth and Environment, Boston University, Boston, MA, United States; Nicholas School of the Environment, Duke University, Durham, NC, United States; Department of Civil and Environmental Engineering, Duke University, Durham, NC, United States; Department of Geography, University of Colorado at Boulder, Boulder, CO, United States
Recommended Citation:
Gao Z.,Liu H.,Li D.,et al. Enhanced Temperature-Humidity Similarity Caused by Entrainment Processes With Increased Wind Shear[J]. Journal of Geophysical Research: Atmospheres,2018-01-01,123(8)