scholarly journals A TKE-Based Framework for Studying Disturbed Atmospheric Surface Layer Flows and Application to Vertical Velocity Variance Over Canopies

2018 ◽  
Vol 45 (13) ◽  
pp. 6734-6740 ◽  
Author(s):  
Marcelo Chamecki ◽  
Nelson L. Dias ◽  
Livia S. Freire
Keyword(s):  
Surface Layer ◽  
Vertical Velocity ◽  
Atmospheric Surface Layer ◽  
Velocity Variance

scholarly journals Extreme fluctuations of vertical velocity in the unstable atmospheric surface layer

2014 ◽  
Vol 21 (2) ◽  
pp. 463-475 ◽  
Author(s):  
L. Liu ◽  
F. Hu ◽  
X.-L. Cheng
Keyword(s):  
Time Series ◽  
Surface Layer ◽  
Vertical Velocity ◽  
Atmospheric Surface Layer ◽  
Waiting Times ◽  
Stable Distributions ◽  
Statistical Characteristics ◽  
Exponential Distributions ◽  
Stretched Exponential ◽  
Statistical Correlations

Abstract. In this paper, we propose a new method to extract the extreme fluctuations of vertical velocity in the unstable atmospheric surface layer. Unlike the commonly used conditional sampling analysis, this method defines a threshold by using a systematical method and tries to reduce the artificiality in this process. It defines threshold as the position where the types of probability density functions (PDFs) of vertical velocity fluctuations begin to change character from stable distributions to truncated stable distributions. Absolute values of fluctuations greater than the threshold are considered to be extreme fluctuations. We then analyze the statistical characteristics of extracted extreme fluctuations of vertical velocity. Our results show that the amplitudes of extreme fluctuations are exponentially distributed, and the waiting times between extreme fluctuations have stretched exponential distributions. It suggests that there are statistical correlations in the time series of vertical velocity because independent time series can only have exponentially distributed waiting times. The durations of extreme fluctuations are also found to be stretched exponential distributed, while for the independent time series the distributions of durations are delta-like. Finally, the PDFs of amplitudes, waiting times and durations are all well parameterized in the context of Monin–Obukhov theory.

Probability law of turbulent kinetic energy in the atmospheric surface layer

2021 ◽  
Vol 6 (7) ◽  
Author(s):  
Mohammad Allouche ◽  
Gabriel G. Katul ◽  
Jose D. Fuentes ◽  
Elie Bou-Zeid
Keyword(s):  
Surface Layer ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Atmospheric Surface Layer

scholarly journals Whirlwinds and Hairpins in the Atmospheric Surface Layer

2016 ◽  
Vol 73 (12) ◽  
pp. 4927-4943 ◽  
Author(s):  
Steven P. Oncley ◽  
Oscar Hartogensis ◽  
Chenning Tong
Keyword(s):  
Surface Layer ◽  
Atmospheric Surface Layer ◽  
Dust Devils ◽  
Hairpin Vortices ◽  
Structure And Dynamics ◽  
Fixed Array ◽  
Visual Observations

Abstract Vortices in the atmospheric surface layer are characterized using observations at unprecedented resolution from a fixed array of 31 turbulence sensors. During the day, these vortices likely are dust devils, though no visual observations are available for confirmation. At night, hairpin vortices appear to have been observed. The structure and dynamics of several types of vortices are described and related to other vortex investigations, including tornadoes and hurricanes.

Sign in / Sign up

Export Citation Format

Share Document