Filed Observation in Urban Boundary Layer and a New Similarity Law

在东京人口密集的居民区进行了动量、热量、水分和CO_2的长期通量测量。因此，提出了与湍流有关的通量、偏差和耗散的新的相似函数。此外，通过小波分析研究了复杂城市几何结构中湍流交换过程的详细机理，得到了以下结果：(1)湍流特征表现出显著的日变化。特别是在早晨，扩展到边界层高度的大尺度湍流组织结构夹带了上层空气，导致了类似的动量、热量、水分和co2的传递。(2)剪切不稳定性和热不稳定性产生的湍流组织结构对湍流输运起主导作用。它们以不同的效率传递热量、水分和二氧化碳。热的湍流传递是最有效的。其原因之一是温度的表面非均质性小于水汽和co2的表面非均质性，另一种可能是热是热羽直接产生的活动标量。

A long-term flux measurement of momentum, heat, moisture and CO_2 has been conducted in densely-built up residential area in Tokyo. Consequently, new similarity functions of flux, deviation and dissipation related to turbulent flow have been proposed. Moreover, the detailed mechanism of turbulent exchange process over a complicated urban geometry has been investigated through wavelet analysis and the following results were obtained. (l) The turbulent characteristics showed a significant diurnal variation. Particularly in the morning, large scale turbulent organized structure extending to boundary layer height entrained the upper air, resulting in the similar transfer of momentum, heat, moisture and C0_2. (2) Turbulent organized structures generated by shear-instability and thermal instability make dominant role on turbulent transport. They transfer heat, moisture, and CO_2 in different efficiency. The turbulent transfer of heat is most effective. One of the reasons is that the surface-heterogeneity of temperature is smaller than those of moisture and CO_2, and another possibility is that heat is the active scalar of direct generation of thermal plumes.