Effects of foliage and sky view factor on the urban thermal environment

We investigated the effects of urban sky view factor and foliage view factor on the thermal environment, based on field experiments in the street canyons of Osaka. Mean radiation temperature (MRT) and physiologically equivalent temperature (PET) are used as the indices of the thermal environment. We found that MRT and PET decrease with a decrease in the sky view factor and with an increase in foliage view factor. The difference of 0.22 in the sky view factor caused a difference of 23°C in PET. A difference of about 0.27 to 0.35 in the foliage view factor caused a difference of about 8.2 to 9.0°C in PET. We tried to convert the effect of wind speed to that of the foliage and found that an increase of about 3ms^-1 in wind speed is necessary to obtain the same effect as a change in the foliage view factor from 0.27 to 0.35. (author)