Analysis of short-term closure of the surface energy balance above short vegetation
Analysis of short-term closure of the surface energy balance above short vegetation
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DOI：
10.1016/j.agrformet.2007.09.003
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发表时间：
2008-01
影响因子：
6.2
通讯作者：
D. Cava;D. Contini;A. Donateo;P. Martano
中科院分区：
文献类型：
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作者：
D. Cava;D. Contini;A. Donateo;P. Martano
在意大利南部的一个地中海站点进行了详细的表面能量平衡研究。在春季和秋季采取的两个数据集的测量表面热通量进行了测试，重点是短期（h）关闭的表面能量收支。分析表明，修正风速测量声波风速计的误差在大迎角的能量收支关闭的影响，一个重要的贡献也来自土壤通量传感器和地面之间的热存储，不仅为振幅，但也为测量通量的相对相位。对时间序列平稳性的分析没有显示出对能量预算的明显影响。相反，它似乎对坐标旋转系统的平均周期的长度很敏感。使用的“长期坐标系”，连同频谱分析表明，通常的30分钟的平均时间太短，包括湍流热通量的整个贡献，2小时的平均周期是更合适的，如果要包括更大的尺度运动的影响。
A detailed study of the surface energy balance was performed at a Mediterranean site in southern Italy. Two data sets of measurements of surface heat fluxes taken in the spring and autumn were tested with emphasis on the short-term (h) closure of the surface energy budget. The analysis shows that correction of the wind speed measurement sonic anemometer error at large angles of attack has influence on the energy budget closure; an important contribution also comes from heat storage between the soil flux sensor and the ground surface, not only for the amplitude but also for the relative phases of the measured fluxes. An analysis of the time series stationarity did not show appreciable effects on the energy budget. Instead, it appeared to be sensitive to the length of the averaging period for the coordinate rotation system. The use of a ‘long term coordinate system’, together with spectral analysis indicated that the usual 30-min averaging time is too short to include the entire contribution of the turbulent heat fluxes and that a 2-h averaging period is more suitable if larger scale motion effects are to be included.