收稿日期: 2008-02-25
修回日期: 2008-04-01
网络出版日期: 2008-04-10
基金资助
国家高技术研究发展计划课题“非均匀下垫面条件下区域蒸散量遥感监测与验证的关键技术研究”(编号:2007AA12Z175);公益性行业(气象)科研专项“大尺度水热通量观测系统的研制与应用研究”(编号:GYHY200706046);国家自然科学基金项目“非均匀下垫面上卫星像元尺度地表通量的研究”(编号:40671128)资助.
A Study on the Data Processing and Quality Assessment of the Eddy Covariance System
Received date: 2008-02-25
Revised date: 2008-04-01
Online published: 2008-04-10
涡动相关仪能够较准确地直接测量地表—大气间的湍流交换,在世界范围内得到了广泛的应用。但它的使用是有条件限制的,如果不进行必要的修正,得到的通量就可能有较大的误差。以密云观测站一年的涡动相关仪观测数据为例进行分析。结果表明:野点值剔除、坐标旋转以及超声温度订正对地表感热、潜热等通量的测量结果影响均在±1%之内,但坐标旋转对动量通量影响较大,必须对潜热和CO2通量进行空气密度效应订正;湍流谱在惯性副区基本满足-2/3次方定律,协谱基本满足-4/3次方定律。经过对观测数据的筛选和处理后,约75%的观测数据质量较好,2%的数据需要剔除。通量贡献源区分析表明,全天和白天均有超过70%的通量源区落在感兴趣区域内,超过90%的通量贡献最大点落在感兴趣区域内。
徐自为 , 宫丽娟 , 李小文 , 王介民 , 刘绍民 . 涡动相关仪观测数据的处理与质量评价研究[J]. 地球科学进展, 2008 , 23(4) : 357 -370 . DOI: 10.11867/j.issn.1001-8166.2008.04.0357
The eddy covariance (EC) technique can measure turbulent exchanges between surface and atmosphere directly, and is now used widely in all of the flux stations. Since this method is based on certain assumptions, the obtained surface fluxes are not true values if there are no necessary corrections. Recent development and some focal points of the eddy-covariance method are reviewed, and used in the processing of the data collected in Miyun station, which is one of the flux stations near Beijing. The analysis of EC data at Miyun station shows: Despiking and the sonic temperature and coordinate rotation corrections have a rather little effects on the surface sensible and latent fluxes (about 1%), however, coordinate rotation has large effect on the momentum flux. The air density correction (WPL correction) is important for water vapor and CO2 fluxes, and should be applied. The turbulent spectral checks in the data quality evaluation are satisfactory. Turbulence stationarity and integral characteristics are used in the flux data quality analysis. After rigorously data screening, the final result shows that about 75% flux data is good, and 2% flux data need to be discarded. Footprint analysis shows for all day and daytime periods, over 70% source area of the fluxes is located in the interested area (non mountainous region) with over 90% of the biggest contribution points in the area.
[1] Wang Jiemin,Wang Weizhen,Ao Yinhuan,et al. Turbulence flux measurements under complicated conditions [J]. Advances in Earth Science,2007,22(8):791-797.[王介民,王维真,奥银焕,等. 复杂条件下湍流通量的观测与分析[J]. 地球科学进展,2007,22(8): 791-797.]
[2] Baldocchi D D. Assessing the eddy covariance technique for evaluating carbon dioxide exchange rates of ecosystems: Past,present and future [J]. Global Change Biology,2003,9: 479-492.
[3] Massman W J,Lee X. Eddy covariance flux corrections and uncertainties in long term studies of carbon and energy exchanges [J]. Agricultural and Forest Meteorology,2002,113: 121-144.
[4] Finnigan J J,Clement R,Malhi Y,et al. A re-evaluation of long-term flux measurement techniques,Part I: Averaging and coordinate rotation [J]. Boundary-Layer Meteorology,2003,107: 1-48.
[5] Webb E K,Pearman G I,Leuning R. Correction of flux measurements for density effects due to heat and water vapour transfer [J]. Quarterly Journal of the Royal Meteorological Society,1980, 106: 85-100.
[6] Wilczak J M,Oncley S P,Stage S A. Sonic anemometer tilt correction algorithms [J]. Boundary-Layer Meteorology,2001,99:127-150.
[7] Foken T,Wichura B. Tools for quality assessment of surface-based flux measurements [J]. Agricultural and Forest Meteorology,1996,78:83-105.
[8] Rebmann C,Göckede M,Foken T. Quality analysis applied on eddy covariance measurements at complex forest sites using footprint modeling [J]. Theoretical and Applied Climatology,2004, DOI:10.1007/s00704-00400095-y.
[9] Göckede M,Rebmann C,Foken T. A combination of quality assessment tools for eddy covariance measurements with footprint modeling for the characterisation of complex sites [J]. Agricultural and Forest Meteorology,2004,127: 175-188.
[10] Mauder M,Liebethal C,Göckede M,et al. Processing and quality control of flux data during LITFASS-2003 [J]. Boundary-Layer Meteorology,2006,121:67-88.
[11] Hammerle A,Haslwanter A,Schmitt M,et al. Eddy covariance measurements of carbon dioxide,latent and sensible energy fluxes above a meadow and a mountain slope [J]. Boundry-Layer Meteorology,2007,122:397-416.
[12] Van Dijk A,Moene A F,De Bruin H A R. The principles of surface flux physics: Theory, practice and description of the ECPACK library [R]. Meteorology and Air Quality Group, Wageningen University,2004:1-97.
[13] Wang Jiemin,Liu Xiaohu,Qi Yongqiang. A preliminary study of turbulence transfer characteristics in Gobi area with an eddy correlation technique [J]. Plateau meteorology,1990,9(2): 120-129.[王介民,刘晓虎,祁勇强.应用涡旋相关方法对戈壁地区湍流输送特征的初步研究[J].高原气象,1990,9(2):120-129.]
[14] Sun Xiaomin,Zhu Zhilin,Xu Jinping,et al. Determination of averaging period parameter and its effects analysis for eddy covariance measurements [J]. Science in China(Series D),2005,48(suppl. 1):33-41.
[15] Zhu Zhilin,Sun Xiaomin,Yuan Guofu,et al. Correcting method of eddy covariance fluxes over non-flat surfaces and its application in ChinaFlux [J]. Science in China(Series D),2005,48(suppl. I): 42-50.
[16] Li Zhengquan,Yu Guirui,Wen Xuefa,et al. Energy balance closure at ChinaFlux sites [J]. Science in China(Series D),2005,48(suppl. I): 51-62.
[17] Wen Xuefa,Yu Guirui,Sun Xiaomin,et al. Turbulence Flux Measurement above the overstory of a subtropical Pinus plantation over the hilly region in southeastern China [J]. Science in China(Series D),2005,48(suppl.I):63-73.
[18] Schotanus P,Nieuwstadt F T M,De Bruin H A R. Temperature measurement with a sonic anemometer and its application to heat and moisture fluxes [J]. Boundary-Layer Meteorology,1983,26: 81-93.
[19] Su Hongbing,Schmid H P,Grimmond C S B,et al. Spectral characteristics and correction of long-term eddy-covariance measurements over two mixed hardwood forests in non-flat terrain [J]. Boundary-Layer Meteorology,2004,110:213-253.
[20] Foken T,Göckede M,Mauder M,et al. Post-field data quality control [C]∥Lee X,Massman M,Law B,eds. Handbook of Micrometeorology. A Guide for Surface flux Measurement and Analysis.Boston: Kluwer Academic,2004: 181-208.
[21] Kaimal J C,Finnigan J J. Atmospheric Boundary Layer Flows: Their Structure and Measurement [M]. New York: Oxford University Press,1994:255-261.
[22] Kormann R,Meixner F X. An analytical footprint model for non-neutral stratification [J]. Boundary-Layer Meteorology,2001,99:207-224.
[23] Guo X,Cai X. Footprint characteristics of scalar concentration in the convective boundary layer [J]. Advances in Atmosphere Sciences,2005,22(6):821-830.
[24] Vickers D,Mahrt L. Quality control and Flux sampling Problems for Tower and Aircraft Data [J]. Journal of atmospheric and oceanic technology,1997,14:512-526.
[25] Guo Jianxia,Bian Lin'gen,Dai Yongjiu. Measured CO2 Concentration and Flux at 16m Height during Corn growing period on the North China Plain [J]. Chinese Journal of Atmospheric Sciences,2007,31(4):695-707. [郭建侠,卞林根,戴永久.在华北玉米生育期观测的16m高度CO2 浓度及通量特征[J]. 大气科学,2007,31(4):695-707.]
[26] Turnipseed A A,Anderson D E,Blanken P D,et al. Airflows and turbulent flux measurements in mountainous terrain Part 1. Canopy and local effects [J]. Agricultural and Forest Meteorology,2003,119:1-21.
[27] Liu Heping,Perters G,Foken T. New equations for sonic temperature variance and buoyancy heat flux with an omnidirectional sonic anemometer [J]. Boundary-Layer Meteorology,2001,100: 459-468.
[28] Bian Lin'gen,Lu Longhua,Cheng Yanjie,et al. Turbulent measurement over the southeastern Tibet plateau [J]. Quarterly Journal of Applied Meteorology,2001,12(1):1-13.[卞林根,陆龙骅,程彦杰,等. 青藏高原东南部昌都地区近地层湍流输送的观测研究[J]. 应用气象学报,2001,12(1):1-13.]
[29] Blanken P D,Black T A,Neumann H H,et al. Turbulence flux measurements above and below the overstory of a boreal aspen forest [J]. Boundary-Layer Meteorology,1998,89: 109-140.
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