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Discrepancy and Applicability of Various Similarity Functions in Flux Calculations Under Stable Conditions

Advances in Atmospheric Sciences 2007年第4期24卷 644-654页

作者：郭晓峰张宏升蔡旭晖康凌李万彪杜金林 Department of Atmospheric Sciences School of PhysicsPeking UniversityBeijing 100871 Department of Environmental Sciences Peking UniversityBeijing 100871

Based on data obtained during the Hualhe River Basin Experiment （HUBEX） in 1999, this study intends to detect the quantitative discrepancies in the momentum （τ0）, sensible heat （H0） and latent heat （E0） fluxes among six sets of similarity functions with the aerodynamic method. It also aims to clarify the applicability of the functions under stable conditions. The relative discrepancy was studied with the normalized transfer coefficients for τ0, H0 and E0, namely CD, CH and CQ, respectively. Except for one set of functions that adopted a rather small von Kármán＇s constant （0.365）, the relative discrepancy in τ0 among the other functions was less than 10%, while that in H0（E0） sometimes reached 25% when the bulk Richardson number （R/B） was less than 0.07. The absolute discrepancy in the fluxes was studied with statistical computations. Among the six sets of functions, the discrepancy in τ0, H0 and E0 sometimes reached 0.03 kg m^-1 s^-2, 4 W m^-2 and 10 W m^-2, respectively, and the discrepancy in the energy balance ratio sometimes exceeded 0.1. Furthermore, when RiB exceeded the critical value （Ric） for a specific set of functions, no fluxes could be derived with the functions. It is therefore suggested that RiB be compared with Ric before computing the fluxes if RiB is less than Ric. Finally, two sets of nonlinear similarity functions are recommended, due to their unlimited applicability in terms of RiB.

关键词： aerodynamic method turbulent flux surface layer similarity function energy balance

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SURFACE IMBALANCE ENERGY CALCULATED AND ANALYZED WITH THE DATA OF EBEX-2000

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Acta meteorologica Sinica 2003年第4期17卷 448-464页

作者：李洁刘树华刘和平 Johnny CHAN Andrew Y.S CHENG 胡非刘辉志 Department of Atmospheric Sciences College of PhysicsPeking University Department of Physics and Materials Science. City University of Hong Kong Department of Physics and Materials Science City University of Hong Kong State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences

*** methods have been developed to calculate turbulence heat *** are eddy covariance method,Bowen ratio/energy balance method and aerodynamic *** 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 *** comparisons of the three methods and some possible explanations of the surface imbalance energy are given.

关键词： surface imbalance energy eddy covariance method. Bowen ratio/energy balance method aerodynamic method

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The Spatial Sensitivity Analysis of Evapotranspiration using Penman-Monteith method at Grid Scale

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Journal of Geographic Information System 2016年第1期8卷 121-136页

作者： Sivarajah Mylevaganam Chittaranjan Ray University of Nebraska-Lincoln Lincoln NE USA

The need to allocate the existing water in a sustainable manner, even with the projected population growth, has made to assess the consumptive use or evapotranspiration (ET), which determines the irrigation demand. As underscored in the literature, Penman-Monteith method which is a combination of aerodynamic and energy balance method is widely used and accepted as the method of estimation of ET. However, the application of Penman-Monteith relies on many climate parameters such as relative humidity, solar radiation, temperature, and wind speed. Therefore, there exists a need to determine the parameters that are most sensitive and correlated with dependent variable (i.e., ET), to strengthen the knowledge base. However, the sensitivity of ET using Penman-Monteith is oftentimes estimated using meteorological data from climate stations. Such estimation of sensitivity may vary spatially and thus there exists a need to estimate sensitivity of ET spatially. Thus, in this paper, based on One-AT-A-Time (OAT) method, a spatial sensitivity tool that can geographically encompass all the best available climate datasets to produce ET and its sensitivity at different spatial scales is developed. The spatial tool is developed as a Python toolbox in ArcGIS using Python, an open source programming language, and the ArcPy site-package of ArcGIS. The developed spatial tool is demonstrated using the meteorological data from Automated Weather Data Network in Nebraska in 2010. To summarize the outcome of the sensitivity analysis using OAT method, sensitivity indices are developed for each raster cell. The demonstration of the tool shows that, among the considered parameters, the computed ET using Penman-Monteith is highly sensitive to solar radiation followed by temperature for the state of Nebraska, as depicted by the sensitivity index. The computed sensitivity index of wind speed and the relative humidity are not that significant compared to the sensitivity index of solar radiation and t

关键词： Evapotranspiration Penman-Monteith method aerodynamic method Energy Balance method Python ArcPy ArcGIS Spatial Scale Geoprocessing Python Toolbox Sensitivity Analysis One-AT-A-Time Sensitivity Index

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A Spatial Evapotranspiration Tool at Grid Scale

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Open Journal of Applied Sciences 2016年第1期6卷 64-77页

作者： Sivarajah Mylevaganam Chittaranjan Ray University of Nebraska-Lincoln Lincoln NE USA

The drastic decline in groundwater table and many other detrimental effects in meeting irrigation demand, and the projected population growth have force to evaluate consumptive use or evapo-transpiration (ET), the rate of liquid water transformation to vapor from open water, bare soil, and vegetation, which determines the irrigation demand. As underscored in the literature, Pen-man-Monteith method which is based on aerodynamic and energy balance method is widely used and accepted as the method of estimation of ET. However, the estimation of ET is oftentimes carried out using meteorological data from climate stations. Therefore, such estimation of ET may vary spatially and thus there exists a need to estimate ET spatially at different spatial or grid scales/resolutions. Thus, in this paper, a spatial tool that can geographically encompass all the best available climate datasets to produce ET at different spatial scales is developed. The spatial tool is developed as a Python toolbox in ArcGIS using Python, an open source programming language, and the ArcPy site-package of ArcGIS. The developed spatial tool is demonstrated using the meteorological data from Automated Weather Data Network in Nebraska in 2010.

关键词： Evapotranspiration Penman-Monteith method aerodynamic method Energy Balance method Python ArcPy ArcGIS Spatial Scale Geoprocessing Python Toolbox

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RADIATION BALANCE AND TURBULENT FLUX CHARACTERISTICS OVER MIZUHO STATION IN ANTARCTICA

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Acta meteorologica Sinica 1993年第3期7卷 316-326页

作者：刘树华于鹏熊康 Department of Geophysics Peking UniversityBeijing 100871 Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029

In this paper,by using measurements in micrometeorology and radiation balance in the surface layer(Yamanouchi et al.,1981;Wada et al.,1981;Ishikawa et al.,1982;Ohata et al.,1983),we have analyzed the diurnal and annual varia- tion characteristics of radiation balance in spring,summer,autumn and winter,and calculated the momentum flux and sensible heat flux with the aerodynamic method and profile gradient alternate method in different *** have also obtained the diurnal variation characters of the latent heat flux from the equation for energy *** results from the calculation are ***,the relationship between the turbulent heat and momentum exchange coefficient and the diurnal variation of the Richardson number is discussed.

关键词： Mizuho Station radiation balance aerodynamic method profile gradient alternation method turbulent flux

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