scholarly journals An Approach for Calculation of Turbulent Transfer Coefficient for Momentum inside Vegetation Canopies

2006 ◽  
Vol 45 (2) ◽  
pp. 348-356 ◽  
Author(s):  
D. T. Mihailovic ◽  
B. Lalic ◽  
J. Eitzinger ◽  
S. Malinovic ◽  
I. Arsenic
Keyword(s):  
Transfer Coefficient ◽  
Land Surface ◽  
Attenuation Factor ◽  
Surface Fluxes ◽  
Turbulent Transfer ◽  
Vegetation Canopy ◽  
Transfer Coefficients ◽  
Vegetation Canopies ◽  
Turbulent Transfer Coefficient ◽  
Wind Profiles

Abstract A method for calculating the profile of turbulent transfer coefficient for momentum inside a vegetation canopy for use in land surface schemes is presented. It is done through the following steps. First, an equation for the turbulent transfer coefficient for momentum inside a vegetation canopy using the “sandwich” approach for its representation is derived. Second, it is examined analytically to determine whether its solution is always positive. Third, the equation for the turbulent transfer coefficient is solved numerically, using an iterative procedure for calculating the attenuation factor in the expression for the wind speed inside a vegetation canopy that is assumed to be a linear combination of an exponential function and a logarithmic function. The proposed method is tested using 1) the observations for the wind profiles in a Japanese larch plantation and a pine forest and 2) the outputs for surface fluxes and total soil water content obtained by the Land–Air Parameterization Scheme (LAPS) with the forcing data and observations in a soybean field at the Caumont site in France during the 1986 growing season. Also, a test is performed that compares the proposed method with the method for calculating the turbulent transfer coefficients for momentum inside a vegetation canopy commonly used in land surface schemes.

scholarly journals Turbulent Transfer Coefficients and Calculation of Air Temperature inside Tall Grass Canopies in Land–Atmosphere Schemes for Environmental Modeling

2004 ◽  
Vol 43 (10) ◽  
pp. 1498-1514 ◽  
Author(s):  
D. T. Mihailovic ◽  
K. Alapaty ◽  
B. Lalic ◽  
I. Arsenic ◽  
B. Rajkovic ◽  
...  
Keyword(s):  
Transfer Coefficient ◽  
Air Temperature ◽  
Land Surface ◽  
Mesoscale Model ◽  
Environmental Modeling ◽  
Turbulent Transfer ◽  
Transfer Coefficients ◽  
Tall Grass ◽  
K Theory ◽  
Turbulent Transfer Coefficient

Abstract A method for estimating profiles of turbulent transfer coefficients inside a vegetation canopy and their use in calculating the air temperature inside tall grass canopies in land surface schemes for environmental modeling is presented. The proposed method, based on K theory, is assessed using data measured in a maize canopy. The air temperature inside the canopy is determined diagnostically by a method based on detailed consideration of 1) calculations of turbulent fluxes, 2) the shape of the wind and turbulent transfer coefficient profiles, and 3) calculation of the aerodynamic resistances inside tall grass canopies. An expression for calculating the turbulent transfer coefficient inside sparse tall grass canopies is also suggested, including modification of the corresponding equation for the wind profile inside the canopy. The proposed calculations of K-theory parameters are tested using the Land–Air Parameterization Scheme (LAPS). Model outputs of air temperature inside the canopy for 8–17 July 2002 are compared with micrometeorological measurements inside a sunflower field at the Rimski Sancevi experimental site (Serbia). To demonstrate how changes in the specification of canopy density affect the simulation of air temperature inside tall grass canopies and, thus, alter the growth of PBL height, numerical experiments are performed with LAPS coupled with a one-dimensional PBL model over a sunflower field. To examine how the turbulent transfer coefficient inside tall grass canopies over a large domain represents the influence of the underlying surface on the air layer above, sensitivity tests are performed using a coupled system consisting of the NCEP Nonhydrostatic Mesoscale Model and LAPS.

scholarly journals Modeling surface fluxes over a sparse vegetation

2012 ◽  
Vol 64 (4) ◽  
pp. 1533-1542 ◽  
Author(s):  
D.T. Mihailovic ◽  
Branislava Lalic ◽  
Jacek Lesny ◽  
J. Olejnik
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Canopy Temperature ◽  
Apple Orchard ◽  
Surface Fluxes ◽  
Turbulent Transfer ◽  
Vegetation Canopy ◽  
Sparse Vegetation ◽  
Turbulent Transfer Coefficient

In this paper some of aspects in modeling over sparse vegetation using the Land-Air Parameterization Scheme (LAPS), including an approach in calculating the turbulent transfer coefficient using ?K-theory? inside a sparse vegetation canopy, were considered. For this purpose, the scheme was run for different sparse agricultural cultivars, i.e., apple orchard, winter wheat and soybean crops, at different sites. The modeled values for surface fluxes, canopy temperature and soil moisture content, were compared with observations.

Turbulent transfer coefficient and roughness length in a high-altitude lake, Tibetan Plateau

2015 ◽  
Vol 124 (3-4) ◽  
pp. 723-735 ◽  
Author(s):  
Zhaoguo Li ◽  
Shihua Lyu ◽  
Lin Zhao ◽  
Lijuan Wen ◽  
Yinhuan Ao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Transfer Coefficient ◽  
High Altitude ◽  
Roughness Length ◽  
Turbulent Transfer ◽  
Turbulent Transfer Coefficient ◽  
High Altitude Lake

scholarly journals An improved non-iterative surface layer flux scheme for atmospheric stable stratification condition

2013 ◽  
Vol 6 (4) ◽  
pp. 6459-6492
Author(s):  
Y. Li ◽  
Z. Gao ◽  
D. Li ◽  
L. Wang ◽  
H. Wang
Keyword(s):  
Full Range ◽  
Stable Stratification ◽  
Iteration Scheme ◽  
Surface Fluxes ◽  
Turbulent Transfer ◽  
Sensible Heat ◽  
Transfer Coefficients ◽  
Iterative Computation ◽  
Stable Conditions ◽  
Relative Errors

Abstract. Parameterization of turbulent fluxes under stably stratified conditions has always been a challenge. Current surface fluxes calculation schemes either need iterations or suffer low accuracy. In this paper, a non-iteration scheme is proposed to approach the classic iterative computation results using multiple regressions. It can be applied to the full range of roughness status 10 ≤ z/z0 ≤ 105 and −0.5 ≤ log(z0/z0h) ≤ 30 under stable conditions 0< RiB ≤ 2.5. The maximum (average) relative errors for the turbulent transfer coefficients for momentum and sensible heat are 12% (1%) and 9% (1%), respectively.

scholarly journals An improved non-iterative surface layer flux scheme for atmospheric stable stratification conditions

2014 ◽  
Vol 7 (2) ◽  
pp. 515-529 ◽  
Author(s):  
Y. Li ◽  
Z. Gao ◽  
D. Li ◽  
L. Wang ◽  
H. Wang
Keyword(s):  
Iterative Scheme ◽  
Full Range ◽  
Stable Stratification ◽  
Surface Fluxes ◽  
Turbulent Transfer ◽  
Sensible Heat ◽  
Transfer Coefficients ◽  
Iterative Computation ◽  
Stable Conditions ◽  
Relative Errors

Abstract. Parameterization of turbulent fluxes under stably stratified conditions has always been a challenge. Current surface fluxes calculation schemes either need iterations or suffer low accuracy. In this paper, a non-iterative scheme is proposed to approach the classic iterative computation results using multiple regressions. It can be applied to the full range of roughness status 10 ≤ z/z0 ≤ 105 and −0.5 ≤ log (z0/z0h) ≤ 30 under stable conditions 0 < RiB ≤ 2.5. The maximum (average) relative errors for the turbulent transfer coefficients for momentum and sensible heat are 12% (1%) and 9% (1%), respectively.

scholarly journals SCOPE 2.0: A model to simulate vegetated land surface fluxes and satellite signals

2020 ◽  
Author(s):  
Peiqi Yang ◽  
Egor Prikaziuk ◽  
Wout Verhoef ◽  
Christiaan van der Tol
Keyword(s):  
Remote Sensing ◽  
Land Surface ◽  
Heat Dissipation ◽  
Chlorophyll Concentration ◽  
Vertical Gradient ◽  
Surface Fluxes ◽  
Canopy Reflectance ◽  
Physically Based ◽  
Vegetation Canopies ◽  
Definition Of

Abstract. The Soil Canopy Observation of Photosynthesis and Energy fluxes (SCOPE) model aims at linking satellite observations in the visible, infrared and thermal domains with land surface processes in a physically based manner, and quantifying the micro-climate in the canopy. It simulates radiative transfer in the soil, leaves and vegetation canopies, as well as photosynthesis and non-radiative heat dissipation through convection and mechanical turbulence. Since the first publication 11 years ago, SCOPE has been applied in remote sensing studies of solar-induced chlorophyll fluorescence (SIF), energy balance fluxes, gross primary productivity (GPP) and directional thermal signals. Here we present a thoroughly revised version, SCOPE 2.0, which features a number of new elements: (1) It enables the definition of layers consisting of leaves with different properties, thus enabling the simulation of vegetation with an understory or with a vertical gradient in leaf chlorophyll concentration; (2) It enables the simulation of soil reflectance; (3) It includes the simulation of leaf and canopy reflectance changes induced by the xanthophyll cycle; and (4) The computation speed has been reduced by 90 % compared to earlier versions due to a fundamental optimization of the model. These new features improve the capability of the model to represent complex canopies and to explore the response of remote sensing signals to vegetation physiology. The improvements in the computational efficiency make it possible to use SCOPE 2.0 routinely for the simulation of satellite data and land surface fluxes. It also strengthens the operability for the numerical retrieval of land surface products from satellite or airborne data.

scholarly journals SCOPE 2.0: a model to simulate vegetated land surface fluxes and satellite signals

2021 ◽  
Vol 14 (7) ◽  
pp. 4697-4712
Author(s):  
Peiqi Yang ◽  
Egor Prikaziuk ◽  
Wout Verhoef ◽  
Christiaan van der Tol
Keyword(s):  
Remote Sensing ◽  
Land Surface ◽  
Heat Dissipation ◽  
Gross Primary Production ◽  
Chlorophyll Concentration ◽  
Vertical Gradient ◽  
Surface Fluxes ◽  
Canopy Reflectance ◽  
Physically Based ◽  
Vegetation Canopies

Abstract. The Soil Canopy Observation of Photosynthesis and Energy fluxes (SCOPE) model aims at linking satellite observations in the visible, infrared, and thermal domains with land surface processes in a physically based manner, and quantifying the microclimate in vegetation canopies. It simulates radiative transfer in the soil, leaves, and vegetation canopies, as well as photosynthesis and non-radiative heat dissipation through convection and mechanical turbulence. Since the first publication 12 years ago, SCOPE has been applied in remote sensing studies of solar-induced chlorophyll fluorescence (SIF), energy balance fluxes, gross primary production (GPP), and directional thermal signals. Here, we present a thoroughly revised version, SCOPE 2.0, which features a number of new elements: (1) it enables the definition of layers consisting of leaves with different properties, thus enabling the simulation of vegetation with an understorey or with a vertical gradient in leaf chlorophyll concentration; (2) it enables the simulation of soil reflectance; (3) it includes the simulation of leaf and canopy reflectance changes induced by the xanthophyll cycle; and (4) the computation speed has been reduced by 90 % compared to earlier versions due to a fundamental optimization of the model. These new features improve the capability of the model to represent complex canopies and to explore the response of remote sensing signals to vegetation physiology. The improvements in computational efficiency make it possible to use SCOPE 2.0 routinely for the simulation of satellite data and land surface fluxes. It also strengthens the operability for the numerical retrieval of land surface products from satellite or airborne data.

Sign in / Sign up

Export Citation Format

Share Document