| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2000: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Research Abstract |
Scintillometer is newly developed instrument for measuring the sensible heat flux by detecting scintillation of twin polarized laser beams. Structure function of temperature is derived from fluctuation of beam strength, and energy dissipation rate is derived from correlation of twin beam.
Sensible heat flux over beam path is estimated from these two parameters of turbulence assuming with the Monin-Obukhov Similarity with some empirical formulas. It has the advantage of measuring path averaged sensible heat flux easily, but prerequisite for measurement, especially in the case of urban area, has not been so clear yet. In this study, observations for verification of sensible heat flux by scintillometer were performed in various kinds of surface, for example river water surface running through built-up area, grassland surface in urban park, paddy field, vegetated stepwise roof-garden, and so on. With the comparison of flux by eddy correlation method, accuracy of scintillometer and some limits of measuring condition were clarified.
In order to check the possibility of application of scintillometer to measure sensible heat flux from vertical building wall surface, the apparatus for path change by mirror refraction are also devised.
The position of the mirror between transmitter and receiver is important. In the case of just after transmitter and just before receiver, there was no influence of mirror refraction on flux measurement. But V-shape path, that is mirror was located at the middle part of laser path, fluctuation of laser strength become rather unstable and could not measure in any incident angle.
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