Dividing the transit wind speeds into intervals as a favorable methodology for analyzing the relationship between wind speed and the aerodynamic impedance of vegetation in semiarid grasslands  

作　　者：LI Ruishen PEI Haifeng ZHANG Shengwei LI Fengming LIN Xi WANG Shuai YANG Lin 

机构地区：[1]College of Water Conservancy and Civil Engineering,Inner Mongolia Agricultural University,Hohhot 010018,China [2]Key Laboratory of Water Resources Protection and Utilization of Inner Mongolia Autonomous Region,Hohhot 010018,China [3]Autonomous Region Collaborative Innovation Center for Integrated Management of Water Resources and Water Environment in the Inner Mongolia Reaches of the Yellow River,Hohhot 010018,China [4]Inner Mongolia Autonomous Region Management Center of Sanshenggong Hydro-junction in the Yellow River,Bayannur 015200,China

出　　处：《Journal of Arid Land》2023年第8期887-900,共14页干旱区科学（英文版）

基　　金：funded by the National Natural Science Foundation of China(52279017 and 52079063);Technological Achievements of Inner Mongolia Autonomous Region of China(2020CG0054 and 2022YFDZ0050);the Graduate Education Innovation Program of Inner Mongolia Autonomous Region of China(B20210188Z);the Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region,China(NMGIRT2313).

摘　　要：In grassland ecosystems,the aerodynamic roughness(Z0)and frictional wind speed(u*)contribute to the aerodynamic impedance of the grassland canopy.Thus,they are often used in the studies of wind erosion and evapotranspiration.However,the effect of wind speed and grazing measures on the aerodynamic impedance of the grassland canopy has received less analysis.In this study,we monitored wind speeds at multiple heights in grazed and grazing-prohibited grasslands for 1 month in 2021,determined the transit wind speed at 2.0 m height by comparing wind speed differences at the same height in both grasslands,and divided these transit wind speeds at intervals of 2.0 m/s to analyze the effect of the transit wind speed on the relationship among Z0,u*,and wind speed within the grassland canopy.The results showed that dividing the transit wind speeds into intervals has a positive effect on the logarithmic fit of the wind speed profile.After dividing the transit wind speeds into intervals,the wind speed at 0.1 m height(V0.1)gradually decreased with the increase of Z0,exhibiting three distinct stages:a sharp change zone,a steady change zone,and a flat zone;while the overall trend of u*increased first and then decreased with the increase of V0.1.Dividing the transit wind speeds into intervals improved the fitting relationship between Z0 and V0.1 and changed their fitting functions in grazed and grazing-prohibited grasslands.According to the computational fluid dynamic results,we found that the number of tall-stature plants has a more significant effect on windproof capacity than their height.The results of this study contribute to a better understanding of the relationship between wind speed and the aerodynamic impedance of vegetation in grassland environments.

关 键 词：transit wind speeds frictional wind speed aerodynamic roughness computational fluid dynamic(CFD) grazed grassland grazing-prohibited grassland 

分 类 号：S812[农业科学—草业科学] P425[农业科学—畜牧学]