收稿日期: 2010-03-16
修回日期: 2010-07-14
网络出版日期: 2010-11-10
基金资助
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“基于地表温度—植被指数三角梯形特征空间的区域蒸散发遥感反演研究”(编号：40871169)资助.
The Uncertainty of Sensible Heat Flux Measurement over Cropland Using Large Aperture Scintillometer (LAS)
Received date: 2010-03-16
Revised date: 2010-07-14
Online published: 2010-11-10
显热通量是反映地—气间能量交换强度的重要指标。随着涡度相关（EC）技术的快速发展，点尺度的显热通量测量已经变得比较容易和准确可靠，像元尺度（公里尺度）的显热通量的地面测量成为连接遥感反演和地面验证尺度扩展的一个重要环节。大孔径闪烁仪（LAS）是目前唯一一种可直接用于像元尺度上显热通量测量的仪器。为了研究该仪器在使用过程的问题，比较了用2种方法同时在禹城农田上观测的显热通量，重点分析了两者之间产生误差或不确定性的原因。初步研究表明：①无论白天还是夜间，用大孔径闪烁仪（LAS）测量像元尺度上的显热通量是可行的，与涡度相关方法得到的结果总体相关性比较好，日变化趋势非常一致。②LAS与EC对比观测表明：白天显热通量较小时，HLAS比HEC偏大，白天显热通量较大时，HLAS比HEC小；当显热通量由小变大时，其平均绝对误差越来越大，相对误差越来越小。③由于下垫面的非均匀性，风速风向变化将会改变通量贡献区（footprint），从而造成2种结果出现偏差。另外，波文比、零平面位移和地表粗糙度等的不确定性都可能影响LAS的观测结果。
关键词： 大孔径闪烁仪（LAS）; 涡度相关; 显热通量; 像元尺度（公里尺度）; 农田
朱治林, 孙晓敏, 贾媛媛, 温学发, 张仁华, 袁国富, 唐新斋 . 基于大孔径闪烁仪（LAS）测定农田显热通量的不确定性分析[J]. 地球科学进展, 2010 , 25(11) : 1199 -1207 . DOI: 10.11867/j.issn.1001-8166.2010.11.1199
Sensible heat flux is an important index for reflecting exchange intensity at surface-atmosphere interface. With the fast development of Eddy Covariance (EC) technique, the local sensible heat flux measurement becomes easier and more reliable. To study regional or global exchanges, the pixel-size flux measurement becomes an important and key step for up-scaling. Large Aperture Scintillometer (LAS) is the best instrument for measuring pixel-size sensible heat flux. To evaluate its accuracy and uncertainty, in this paper, the sensible heat fluxes over cropland measured by LAS and EC methods were compared, especially the reasons for errors and uncertainties were analyzed. It shows that: ①No matter in daytime or nighttime, the changing trends of the sensible heat flexes by two methods are the same. The relationship between them is very good, especially during strong exchange periods. ②There are still differences between two sensible heat fluxes. The mean abstract difference is less than 50 W/m2. Generally, when daytime flux is weak (about less than 70 W/m2), the flux measured by LAS (HLAS) is larger than that by EC (HEC), and when flux is strong, HLAS is smaller than HEC. ③Due to the heterogeneous surface, the LAS footprint will be affected by the wind speed and wind direction. Advection may induce the uncertainty for LAS sensible heat flux. In addition, based on all the variables and parameters for LAS equations, the possible sources of the uncertainty, including the uncertainty of EC method and its effect on Bowen ratio, the inaccuracy and changeable parameters (e.g. zero plane displacement and surface roughness etc.) were analyzed.
[1] Zhu Zhilin, Sun Xiaomin, Zhang Renhua,et al. The estimate of energy and mass exchanges in Inner Mongolia semi-arid grassland using micrometeorological methods[J].Climate and Environment Research,2001,8(2):214-220.[朱治林,孙晓敏,张仁华,等，淮河流域典型地面水热通量的观测分析[J].气候与环境研究, 2001, 8(2): 214-220.]
[2] Baldocchi D, Falge E, Gu L, et al. FLUXNET: A new tool to study the temporal and spatial variability of ecosystem-scale carbon dioxide, water vapor and energy flux densities[J].Bulletin of the Amenicen Meteorological Society, 2001, 82: 2 415-2 434.
[3] Massman W J, Lee X. Eddy covariance corrections and uncertainties in long-term studies of carbon and energy exchanges[J].Agricultural and Forest Meteorology, 2002, 113:121-144.
[4] Zhang Renhua, Sun Xiaomin, Wang Weimin, et al. An opertional two-layer remote sensing model to estimate surface flux in regional scale: Physical background[J].Science in China (Series D),2005, 48(suppl.I): 225-244.
[5] Wang T I, Ochs G R, Clifford S F. A saturation-resistant optical scintillometer to measure C2n[J].Journal of the Optical Society of America,1978,69: 334-338.
[6] Hoedjes J C B, Zuupbier R M，Watts C J.Large aperture scintillometer used over a homogeneous irrigated area, partly affected by regional advection[J].Boundary-Layer Meteorology,2002, 105: 99-117.
[7] Beyrich F,De Bruin H A R,Meijninger W M L,et al.Results from one-year continuous operation of a large aperture scintillometer over a heterogeneous land surface[J].Boundary-Layer Meteorology,2002, 105: 85-97.
[8] Green A E, Astill M S, McAneney K J,et al.Path-averaged surface fluxes determined from infrared and microwave scintillometers[J].Agricultural and Forest Meteorology,2001, 109: 233-247.
[9] Chehbouni A, Watts C, Lagouarde J P, et al., Estimation of heat and momentum fluxes over complex terrain using a large aperture scintillometer[J].Agricultural and Forest Meteorology, 2000, 105:215-226.
[10] De Bruin H A, Kohsiek W, Van den Hurk. A verification of some methods to determine the fluxes of momentum, sensible heat and water vapour using standard deviation and structure parameter of scalar meteorological quantities[J].Boundary-Layer Meteorology,1993, 63: 231-257.
[11] Hu Liqin, Wu Rongzhang, Fang Zongyi.Large aperture scintillometer and its application to surface energy balance monitoring[J].Journal of Applied Meteorological Science, 2003，14(2）:197-205.[胡丽琴, 吴蓉璋 方宗义. 大口径闪烁仪及其在地表能量平衡监测中的应用[J].应用气象学报，2003，14（2）:197-205.]
[12] Fan Xiong，Deng Biao. Estimation of each flux in energy balance with LAS data [J]. Journal of Sichuan Meteorology，2002，82（4）：30-31.[范雄，邓彪.利用LAS资料估算能量平衡各分量[J]. 四川气象，2002，82（4）：30-31.]
[13] Zhi Keguang，Tu Gang，Lian Yi，et al. Measuring sensible heat fluxes over saline-alkali land area in Qian＇an district［J］. Acta Meteorologica Sinica，2002，60（6）：780-785.［支克广，涂钢，廉毅，等. 乾安地区盐碱地显热通量的测量[J］. 气象学报，2002，60（6）：780-785.］
[14] Lu Li，Liu Shaomin，Sun Minzhang，et al. Advances in the study of areal surface fluxes with large aperture scintillometer[J]. Advances in Earth Science, 2005，20(9）:931-938.[卢俐，刘绍民，孙敏章，等.大孔径闪烁仪研究区域地表通量的进展[J].地球科学进展,2005,20(9）:932-938.]
[15] Schotanus P, Nieuwstadt F T M, De Bruin, et al.Temperature measurement with a sonic anemometer and its application to heat and moisture fluctuations[J].Boundary-Layer Meteorology,1983, 26: 81-93.
[16] Lee X, Massman W J, Law B, eds. Handbook of Micrometeorology: A Guide for Surface Flux Measurements[M].Kluwer:Academic Publishers, 2004.
[17] Lu Li，Liu Shaomin，Xu Ziwei，et al. Results from measurements of large aperture scintillometer over different surfaces[J]. Journal of Applied Meteorological Science,2009，20(9):171-178.[卢俐，刘绍民，徐自为，等. 不同下垫面大孔径闪烁仪观测数据处理与分析[J].应用气象学报,2009,20(2）:171-178.]
[18] Kell W,Allen G, Eva F, et al. Energy balance closure at FLUXNET sites[J].Agricultural and Forest Meteorology, 2002, 113: 223-243.
[19] 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.
[20] Zhou Yanlian, Sun Xiaomin, Zhu Zhilin, et al. Surface roughness length dynamic over several different surfaces and its effect on modeling fluxes[J].Science in China (Series D), 2006, 49(suppl. II): 262-272.
/
| 〈 |
|
〉 |
甘公网安备62010202000687
