Surface layer scintillometry for estimating the sensible heat flux component of the surface energy balance
Surface layer scintillometry for estimating the sensible heat flux component of the surface energy balance
复制标题
用于估计表面能量平衡的感热通量分量的表面层闪烁测量法
DOI：
10.4102/sajs.v105i5/6.92
复制
发表时间：
2010
影响因子：
2.4
通讯作者：
M. J. Savage
中科院分区：
文献类型：
--
作者：
G. Odhiambo;M. J. Savage
最近开发的湍流测量法，重点是双光束表面层湍流测量仪（SLS），允许边界层大气湍流，表面显热和动量通量进行实时估计。以前的大多数研究都采用了大孔径激光散射计法，只有少数研究采用了SLS法。SLS方法主要被农业气象学家、水文学家和微气象学家用于大气稳定性和地表能量平衡研究，以获得感热估计值，从而有可能估计代表一公顷或更大面积的蒸发量。其他应用包括SLS方法在获得大气扩散和湍流模型的关键输入参数中的使用。SLS方法依赖于发射器和接收器之间的水平激光束的光学闪烁，其间隔距离通常在50和250 m之间，这是由大气中的折射率不均匀性引起的，所述折射率不均匀性由空气温度的湍流波动引起，并且在较小程度上由水蒸气压力的波动引起。SLS光束传输的测量允许大气湍流被确定，从亚小时，实时和原位路径加权通量的感热和动量可以计算通过应用莫宁-奥布霍夫相似理论。不像涡度相关（EC）的方法，适用于校正流变形和坐标旋转，没有校正SLS测量，除了水蒸气压力的校正，被应用。此外，路径加权SLS估计的传播路径。与EC、Bowen比能量平衡、表面更新和其他显热测量方法相比，SLS方法还提供了高的时间测量分辨率和通常更大的空间覆盖范围。应用缩短的表面能量平衡，净辐照度和土壤热的测量以及感热的SLS估计允许估计从表面的路径加权蒸发。研究应用涉及使用的SLS方法，以及该方法所依据的理论，提出。
The relatively recently developed scintillometry method, with a focus on the dual-beam surface layer scintillometer (SLS), allows boundary layer atmospheric turbulence, surface sensible heat and momentum flux to be estimated in real-time. Much of the previous research using the scintillometer method has involved the large aperture scintillometer method, with only a few studies using the SLS method. The SLS method has been mainly used by agrometeorologists, hydrologists and micrometeorologists for atmospheric stability and surface energy balance studies to obtain estimates of sensible heat from which evaporation estimates representing areas of one hectare or larger are possible. Other applications include the use of the SLS method in obtaining crucial input parameters for atmospheric dispersion and turbulence models. The SLS method relies upon optical scintillation of a horizontal laser beam between transmitter and receiver for a separation distance typically between 50 and 250 m caused by refractive index inhomogeneities in the atmosphere that arise from turbulence fluctuations in air temperature and to a much lesser extent the fluctuations in water vapour pressure. Measurements of SLS beam transmission allow turbulence of the atmosphere to be determined, from which sub-hourly, real-time and in situ path-weighted fluxes of sensible heat and momentum may be calculated by application of the Monin-Obukhov similarity theory. Unlike the eddy covariance (EC) method for which corrections for flow distortion and coordinate rotation are applied, no corrections to the SLS measurements, apart from a correction for water vapour pressure, are applied. Also, path-weighted SLS estimates over the propagation path are obtained. The SLS method also offers high temporal measurement resolution and usually greater spatial coverage compared to EC, Bowen ratio energy balance, surface renewal and other sensible heat measurement methods. Applying the shortened surface energy balance, measurements of net irradiance and soil heat as well as SLS estimates of sensible heat allows path-weighted evaporation from the surface to be estimated. Research applications involving the use of the SLS method, as well as the theory on which the method is based, are presented.