Mainly.three methods have been developed to calculate turbulence heat flux.They are eddy covariance method,Bowen ratio/energy balance method and aerodynamic method.In this paper, all the three methods have been used t...Mainly.three methods have been developed to calculate turbulence heat flux.They are eddy covariance method,Bowen ratio/energy balance method and aerodynamic method.In this paper, all the three methods have been used to calculate sensible heat flux,latent heat flux and imbalance energy near the surface with the experiment data of EBEX-2000.Then comparisons of the three methods and some possible explanations of the surface imbalance energy are given.展开更多
Accurate estimation of evapotranspiration is important in efficient water management for improving water use efficiency.In order to obtain evapotranspiration and evaporation beneath the canopy using the Food and Agric...Accurate estimation of evapotranspiration is important in efficient water management for improving water use efficiency.In order to obtain evapotranspiration and evaporation beneath the canopy using the Food and Agriculture Organization(FAO)method,pan evaporation was used instead of reference evapotranspiration calculated by the Penman-Monteith equation with detailed meteorological data.The total crop coefficient and soil evaporation coefficient were determined using actual measured daytime evapotranspiration and evaporation by the Bowen ratio energy balance and lysimeter,respectively,in a rice paddy field in Japan.The average evapotranspiration was 5.3 mm/d,4.4 mm/d,7.4 mm/d and 6.3 mm/d and crop coefficient was 0.79,1.18,1.01 and 0.86 for the initial stage,development stage,middle-season stage and late-season stage,respectively.The evaporation was low and almost constant with an average value around 0.77 mm/d when the leaf area index(LAI)reached 3.The proposed average crop coefficients for different growing stages were applied to estimate daytime evapotranspiration and found suitable.A simple soil water evaporation coefficient model was developed using leaf area index for practical use and it was found that it could accurately estimate evaporation.展开更多
基金National Natural Science Foundation of China Grant 40275004City University of Hong Kong Grant 8780046+1 种基金the City University of Hong Kong Strategic Research Grant 7001038State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry
文摘Mainly.three methods have been developed to calculate turbulence heat flux.They are eddy covariance method,Bowen ratio/energy balance method and aerodynamic method.In this paper, all the three methods have been used to calculate sensible heat flux,latent heat flux and imbalance energy near the surface with the experiment data of EBEX-2000.Then comparisons of the three methods and some possible explanations of the surface imbalance energy are given.
基金supported by the Natural Science Foundation of China(51509107,51609103)the Key Laboratory of Agricultural Water Resources,the Chinese Academy of Sciences(No.KFKT201605)+3 种基金Natural Science Foundation of Jiangsu province(BK20140546,BK20150509)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(2015,No.311)Jiangsu University Senior Professional Scientific Research Fund Project(14JDG015,14JDG017,12JDG097)Jiangsu Universities Engineering Discipline Construction Project(1033000001).
文摘Accurate estimation of evapotranspiration is important in efficient water management for improving water use efficiency.In order to obtain evapotranspiration and evaporation beneath the canopy using the Food and Agriculture Organization(FAO)method,pan evaporation was used instead of reference evapotranspiration calculated by the Penman-Monteith equation with detailed meteorological data.The total crop coefficient and soil evaporation coefficient were determined using actual measured daytime evapotranspiration and evaporation by the Bowen ratio energy balance and lysimeter,respectively,in a rice paddy field in Japan.The average evapotranspiration was 5.3 mm/d,4.4 mm/d,7.4 mm/d and 6.3 mm/d and crop coefficient was 0.79,1.18,1.01 and 0.86 for the initial stage,development stage,middle-season stage and late-season stage,respectively.The evaporation was low and almost constant with an average value around 0.77 mm/d when the leaf area index(LAI)reached 3.The proposed average crop coefficients for different growing stages were applied to estimate daytime evapotranspiration and found suitable.A simple soil water evaporation coefficient model was developed using leaf area index for practical use and it was found that it could accurately estimate evaporation.
