STUDY ON URBAN HEAT ISLAND MEASURE EFFECTS BY THE WIND EXCHANGE IN THE URBAN AREA USING UPPER WEATHER DATA

Abstract

It is considered the relationship between the wind path in the urban area and the momentum flux in surface boundary layer using upper weather data observed at Osaka tower and four towers that located between Osaka city and Higashi-Osaka city. Calculation methods for momentum and sensible heat flux and their transfer coefficients between near surface and upper air are explained according to the momentum and heat budget model in surface boundary layer. Momentum transfer coefficient is estimated with observation data at Osaka tower and four towers. The difference between daytime and nighttime is around two or three times. The differences by the year and between each tower are almost ignored. Because momentum and sensible heat flux in surface boundary layer is small in the case of relatively large wind velocity nearby the ground surface in the urban area, improving wind environment in the street is not generally compatible with improving the heat exchange characteristic of the urban area as the urban heat island measure.