Interaction of aerodynamic roughness length and windflow conditions and its parameterization over vegetation surface

Zhang, Qiang; Zeng, Jian; Tong, Yao

doi:10.1007/s11434-012-5000-y

Cited by 26 publications

(17 citation statements)

References 16 publications

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“…Although the R 2 values are not high (maximum value of 0.3696), these results indicate that the wind speed at 5 m possibly has an influence on the z0m over sparse Tamarix at Si Daoqiao site. This finding is consistent with discussions in the literature that meteorological factors could influence the z0m [35,36].…”

Section: Relationship Analysessupporting

confidence: 93%

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Sensitivity of BRDF, NDVI and Wind Speed to the Aerodynamic Roughness Length over Sparse Tamarix in the Downstream Heihe River Basin

Xing

Niu

et al. 2018

Remote Sensing

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Abstract:The aerodynamic roughness length (z0m) is an important parameter that affects the momentum and energy exchange between the earth surface's and the atmosphere. In this paper, the gradient wind speed data that were observed from May to October, 2014, at the Si Daoqiao station, which is located in an area of sparse Tamarix in the downstream region of the Heihe River Basin (HRB), are used to evaluate the sensitivity of the moderate-resolution imaging spectroradiometer (MODIS) near-infrared (NIR) bi-directional reflectance distribution function (BRDF) R, the MODIS/Landsat 8 normalized difference vegetation index (NDVI), and the wind speed at 5 m in comparison with the field-measured z0m. The results indicate that the NIR BRDF_R_MODIS and the NDVI MODIS /NDVI Landsat8 are less sensitive indicators of the z0m over sparse Tamarix areas (R 2 : 0.0045 for NIR BRDF_R MODIS ; R 2 : 0.0342 for NDVI MODIS ; and, R 2 : 0.1646 for NDVI Landsat8 ), which differs significantly from the results obtained by previous studies for farmlands and grasslands. However, there is a nearly linear correlation between the wind speed at 5 m and the z0m at the time scale of the NDVI Landsat8 acquisitions (R 2 : 0.3696). Furthermore, the combination of the NDVI and wind speed at 5 m can significantly improve this correlation (R 2 : 0.7682 for NDVI MODIS ; R 2 : 0.6304 for NDVI Landsat8 ), whereas the combination of the NIR BRDF_R MODIS and wind speed at 5 m still has a low correlation (R 2 : 0.0886). Finally, the regional z0m of the oasis in the downstream region of the HRB was determined using Landsat 8 surface reflectance data and the wind speed data at the Si Daoqiao station, which properly reflect the temporal evolution of the z0m in that region. The parameterization scheme proposed in this paper has great potential to be applied to evapotranspiration, land surface, and hydrologic model simulations of sparse Tamarix at Si Daoqiao site in the future.

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Section: Relationship Analysessupporting

confidence: 93%

“…A z0m experiment over arid South Tunisia during the spring of 2000 [36] found that the field average z0m is 0.353 m for sparse olive trees that are 3 m high with a spacing of 23 m. Thus, the z0m results in this study are comparable to published field results.…”

Section: The Rationality Of Z0msupporting

confidence: 83%

Sensitivity of BRDF, NDVI and Wind Speed to the Aerodynamic Roughness Length over Sparse Tamarix in the Downstream Heihe River Basin

Xing

Niu

et al. 2018

Remote Sensing

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“…Several methods have been used based on this theory to evaluate the statistical turbulence variables (friction velocity, surface roughness length, Obukhov length, etc.) [39][40][41][42][43][44]. We determined the surface friction velocity * u using the momentum flows ' ' u v (covariance of vertical and longitudinal wind component) and ' ' v w (covariance of vertical and transversal wind component) along with the Monin-Obukhov theory:…”

Section: Friction Velocitymentioning

confidence: 99%

Wind Turbulence Intensity Characteristics at 10m Above Ground Along the Cotonou Coast, Benin

Donnou¹,

Akpo²,

Djossou³

et al. 2019

IJSGE

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The characteristics of the wind turbulence intensity that are essential to know before installing a wind turbine at a site were investigated along the coast of Cotonou in Benin. The average speed, direction, roughness length, friction velocity, turbulence intensity and relationship between the roughness and wind turbulence intensity were evaluated as well. Using the estimators derived from a simple isotropic Gaussian model of turbulent wind fluctuations, we proposed modified models for estimating the turbulence intensity of wind components. Wind speed and direction data recorded at 10 m above ground level from 2011 to 2014 during the first Compact of the Millennium Challenge Account (MCA) in Benin were utilized. The results obtained indicated that the annual average roughness length is evaluated at 1.25×10-4 m, and the annual mean friction velocity is equal to 0.41 m.s-1. Peak values of the turbulence intensity vary from 0.3 to 0.6 except during the months of January, April, July, August and September. The high values obtained could jeopardize the production of wind energy during these months. The correlation between the turbulence intensity and roughness length ranging from 0.75 in January to 0.94 in August revealed that these two parameters are linked by an increasing linear function. Finally, modified formulations of the longitudinal and transversal wind turbulence intensity developed from the van den Hurk and de Bruin model and based on the best-fitting approach were proposed. The error estimators (MAE; RMSE) computed to validate these modified models vary respectively from (0.0099; 0.0141) to (0.0614; 0.0890).

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“…Little change in crop height or canopy area index occurred at our desert site during spring, thus z 0 remained constant. Zhang et al (2012) reported that z 0 undergoes a dynamic change over vegetation surfaces due to interactions between vegetation and wind flow. Toure et al (2011) reported that there was a good relation between z 0 and crop residue cover.…”

Section: Aerodynamic Roughnessmentioning

confidence: 99%

Aerodynamic properties of agricultural and natural surfaces in northwestern Tarim Basin

Feng

Sharratt

et al. 2015

Agricultural and Forest Meteorology

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Interaction of aerodynamic roughness length and windflow conditions and its parameterization over vegetation surface

Cited by 26 publications

References 16 publications

Sensitivity of BRDF, NDVI and Wind Speed to the Aerodynamic Roughness Length over Sparse Tamarix in the Downstream Heihe River Basin

Sensitivity of BRDF, NDVI and Wind Speed to the Aerodynamic Roughness Length over Sparse Tamarix in the Downstream Heihe River Basin

Wind Turbulence Intensity Characteristics at 10m Above Ground Along the Cotonou Coast, Benin

Aerodynamic properties of agricultural and natural surfaces in northwestern Tarim Basin

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