scholarly journals Length Scales of the Neutral Wind Profile over Homogeneous Terrain

2010 ◽  
Vol 49 (4) ◽  
pp. 792-806 ◽  
Author(s):  
Alfredo Peña ◽  
Sven-Erik Gryning ◽  
Jakob Mann ◽  
Charlotte B. Hasager
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Wind Speed ◽  
Wind Profile ◽  
Mixing Length ◽  
Speed Profile ◽  
Wind Speed Profile ◽  
Length Scales ◽  
Spectral Models ◽  
Good Agreement

Abstract The wind speed profile for the neutral boundary layer is derived for a number of mixing-length parameterizations, which account for the height of the boundary layer. The wind speed profiles show good agreement with the reanalysis of the Leipzig wind profile (950 m high) and with combined cup–sonic anemometer and lidar measurements (300 m high) performed over flat and homogeneous terrain at Høvsøre, Denmark. In the surface layer, the mixing-length parameterizations agree well with the traditional surface-layer theory, but the wind speed profile is underestimated when the surface-layer scaling is extended to the entire boundary layer, demonstrating the importance of the boundary layer height as a scaling parameter. The turbulence measurements, performed up to 160-m height only at the Høvsøre site, provide the opportunity to derive the spectral-length scales from two spectral models. Good agreement is found between the behaviors of the mixing- and spectral-length scales.

scholarly journals The interaction between drifting snow and atmospheric turbulence

1998 ◽  
Vol 26 ◽  
pp. 167-173 ◽  
Author(s):  
Richard Bintanja
Keyword(s):  
Surface Layer ◽  
Wind Speed ◽  
Atmospheric Surface Layer ◽  
Order Approximation ◽  
Atmospheric Stability ◽  
Blowing Snow ◽  
Speed Profile ◽  
Stability Parameters ◽  
Wind Speed Profile ◽  
First Order

This paper presents a modelling study of the influence of suspended snow on turbulence in the atmospheric surface layer. Turbulence is diminished in drifting and blowing snow, since part of the turbulent energy is used to keep the particles in suspension. This decrease in turbulence directly affects the vertical turbulent fluxes of momentum and snow particles (and other scalars), and can effectively be simulated by introducing an appropriate Richardson number to account for the stability effects of the stably stratified air-snow mixture. We use a one-dimensional model of the atmospheric surface layer in which the Reynolds stress and turbulent suspended snow flux are parameterized in terms of their mean vertical gradients (first-order closure). The model calculates steady-state vertical profiles of mean wind speed, suspended snow mass in 16 size classes and stability parameters. Using the model, the influence of snowdrifting on the wind-speed profile is quantified for various values of the initial friction Velocity (which determines the steepness of the initial wind-speed profile). It will be demonstrated why the roughness length appears to increase when snowdrifting occurs. Finally, we present a parameterization of the effects of snowdrifting on atmospheric stability which can be used in data analyses as a first-order approximation.

The Influence of Thermal Effects on the Wind Speed Profile of the Coastal Marine Boundary Layer

2004 ◽  
Vol 112 (3) ◽  
pp. 587-617 ◽  
Author(s):  
Bernhard Lange ◽  
Søren Larsen ◽  
Jørgen Højstrup ◽  
Rebecca Barthelmie
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Thermal Effects ◽  
Marine Boundary Layer ◽  
Speed Profile ◽  
Wind Speed Profile ◽  
Coastal Marine

Effects of turbulent dispersion on the wind speed profile in the surface layer

2002 ◽  
Vol 19 (5) ◽  
pp. 794-806 ◽  
Author(s):  
Liu Shikuo ◽  
Peng Weihong ◽  
Huang Feng ◽  
Chi Dongyan
Keyword(s):  
Surface Layer ◽  
Wind Speed ◽  
Turbulent Dispersion ◽  
Speed Profile ◽  
Wind Speed Profile

scholarly journals The interaction between drifting snow and atmospheric turbulence

1998 ◽  
Vol 26 ◽  
pp. 167-173 ◽  
Author(s):  
Richard Bintanja
Keyword(s):  
Surface Layer ◽  
Wind Speed ◽  
Atmospheric Surface Layer ◽  
Order Approximation ◽  
Atmospheric Stability ◽  
Blowing Snow ◽  
Speed Profile ◽  
Stability Parameters ◽  
Wind Speed Profile ◽  
First Order

This paper presents a modelling study of the influence of suspended snow on turbulence in the atmospheric surface layer. Turbulence is diminished in drifting and blowing snow, since part of the turbulent energy is used to keep the particles in suspension. This decrease in turbulence directly affects the vertical turbulent fluxes of momentum and snow particles (and other scalars), and can effectively be simulated by introducing an appropriate Richardson number to account for the stability effects of the stably stratified air-snow mixture. We use a one-dimensional model of the atmospheric surface layer in which the Reynolds stress and turbulent suspended snow flux are parameterized in terms of their mean vertical gradients (first-order closure). The model calculates steady-state vertical profiles of mean wind speed, suspended snow mass in 16 size classes and stability parameters. Using the model, the influence of snowdrifting on the wind-speed profile is quantified for various values of the initial friction Velocity (which determines the steepness of the initial wind-speed profile). It will be demonstrated why the roughness length appears to increase when snowdrifting occurs. Finally, we present a parameterization of the effects of snowdrifting on atmospheric stability which can be used in data analyses as a first-order approximation.

scholarly journals Variations in Friction Velocity with Wind Speed and Height for Moderate-to-Strong Onshore Winds Based on Measurements from a Coastal Tower

2020 ◽  
Vol 59 (4) ◽  
pp. 637-650 ◽  
Author(s):  
Pingzhi Fang ◽  
Wendong Jiang ◽  
Jie Tang ◽  
Xiaotu Lei ◽  
Jianguo Tan
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Wind Speed ◽  
Wind Direction ◽  
Friction Velocity ◽  
Wind Profile ◽  
Wind Data ◽  
Profile Data ◽  
Onshore Wind ◽  
Critical Wind Speed

AbstractVariations in friction velocity with wind speed and height are studied under moderate (≥9 m s−1)-to-strong onshore wind conditions caused by three landfalling typhoons. Wind data are from a coastal 100-m tower equipped with 20-Hz ultrasonic anemometers at three heights. Results show that wind direction affects variations in friction velocity with wind speed. A leveling off or decrease in friction velocity occurs at a critical wind speed of ~20 m s−1 under strong onshore wind conditions. Friction velocity does not always decrease with height in the surface layer under typhoon conditions. Thus, height-based corrections on friction velocities using the model from Anctil and Donelan may not be reliable. Surface-layer heights predicted by the model that are based on Ekman dynamics are verified by comparing with those determined by a proposed method that is based on the idea of mean boundary layer using wind-profile data from one of the landfalling typhoons. Friction velocity at the top of the surface layer is then estimated. Results show that friction velocity decreases by about 20% from its surface value and agrees well with previous results of Tennekes.

Evaluation of parametric laws for computing the wind speed profile in the urban boundary layer: comparison to two-dimensional building water channel data

2018 ◽  
Vol 64 (1/2/3) ◽  
pp. 4
Author(s):  
Annalisa Di Bernardino ◽  
Armando Pelliccioni ◽  
Paolo Monti ◽  
Giovanni Leuzzi ◽  
Giorgio Querzoli
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Water Channel ◽  
Urban Boundary Layer ◽  
Two Dimensional ◽  
Speed Profile ◽  
Wind Speed Profile

scholarly journals An empirical-analytical model of the vertical wind speed profile above and within an Amazon forest site

2015 ◽  
Vol 23 (1) ◽  
pp. 158-164 ◽  
Author(s):  
Cledenilson Mendonça de Souza ◽  
Cléo Quaresma Dias-Júnior ◽  
Júlio Tóta ◽  
Leonardo Deane de Abreu Sá
Keyword(s):  
Wind Speed ◽  
Analytical Model ◽  
Vertical Wind ◽  
Forest Site ◽  
Amazon Forest ◽  
Speed Profile ◽  
Wind Speed Profile ◽  
Vertical Wind Speed
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