Validation of fluxes of an extra large aperture scintillometer at Cabauw using Sky Arrow aircraft flux measurements
Validation of fluxes of an extra large aperture scintillometer at Cabauw using Sky Arrow aircraft flux measurements
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发表时间：
2006-05
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通讯作者：
A. Moene;W. Meijninger;W. Kohsiek;B. Gioli;F. Miglietta;F. Bosveld
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作者：
A. Moene;W. Meijninger;W. Kohsiek;B. Gioli;F. Miglietta;F. Bosveld
超大孔径闪烁仪 (XLAS) 已在 Cabauw 塔运行多年，路径长 9.8 公里，平均高度 43 米（Kohsiek 等人，2002 年）。这产生了面积平均感热通量的长期记录。在 2002 年 7 月 27 日的 RECAB 夏季活动期间，Sky Arrow 通量飞机每天有四次在大约 70 米（以及另外两个高度）处靠近闪烁仪路径飞行（Vila-Guerau de Arellano 等，2004）。首先，飞机数据用于验证从 XLAS 获得的通量。由于飞机测量飞行高度的局部通量，而闪烁仪估计表面通量，因此需要考虑飞机下方的通量发散。该通量散度是根据 Cabauw 桅杆沿线的温度分布估算的。闪烁仪和飞机的通量在各自的精度范围内非常匹配。其次，研究了飞机沿路径产生的通量的变化。尽管土地利用相当均匀，但当飞行滞后被细分为五个部分时，可以发现一些统计上显着的差异。其中一些变化在一天中的不同时间之间是恒定的，因此应该与下垫面的特性相关，而其他变化似乎是随机的。最后，利用飞行器数据研究了折射率结构参数沿飞行滞后的空间变化，以研究闪烁仪代表路径平均结构参数的效果。
An extra-large aperture scintillometer (XLAS) has been operated at the Cabauw tower for several years over a path of 9.8 kilometers, at an average height of 43 meters (Kohsiek et al., 2002). This yields a long term record of the area-averaged sensible heat flux. During the RECAB summer campaign on July 27 2002, the Sky Arrow flux aircraft was flown close to the path of the scintillometer at approximately 70 meters (and two more levels) at four times of the day (Vila-Guerau de Arellano et al., 2004). First the aircraft data are used to validate the fluxes obtained from the XLAS. Since the aircraft measures the local flux at flying altitude, whereas the scintillometer estimates the surface flux, the flux divergence below the plane needs to be taken into account. This flux divergence is estimated from the temperature profile along the Cabauw mast. The fluxes of the scintillometer and the aircraft match very well, within their respective accuracies. Secondly, the variability of the aircraft-derived flux along the path is investigated. Despite the rather homogeneous land use, some -statistically significant- differences could be found when the flight-lag was subdivided into five parts. Some of this variability was constant between different times of the day, and should thus be linked to properties of the underlying surface, whereas other variations appeared to be random. Finally, the spatial variability of the structure parameter of the refractive index along the flight lag is investigated using the aircraft data, in order to study how well the scintillometer represents the path-average structure parameter.