Tomohiro YAMADA Tokyo Inst. Tech. Graduate Student A field observation was conducted at a reed field which locates near the mouse of Tama river in Tokyo , in which turbulence in and above reed canopy, deflection of reed and transport of sensible heat were observed. The turbulence was found to have a structure of 3D organized vortices which are induced by a shear instability near the top of the plant canopy. The vortices were observed to be composed of strong sweep and weak ejection. The waving

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... f reed termed honami was induced by the organized vortices. The temporal fluctuation of temperature shows ramp pattern, for which the correlation between the velocity and the temperature fluctuation is not linear. The present observation suggests that the organized vortices are the major agency for exchange of fluid momentum, heat and other substances between in and above plant canopy.