The Influence of Evapotranspiration by Urban Greenery on Thermal Environment in Urban Microclimate

摘要

The purpose of this research is to discuss the phenomena and temperature induced by the evapotranspiration from urban street greenery and pavement construction. We expect to achieve a good ventilation and temperature reduction with the improvement of planting and the pavement material. This research utilized Penman-Monteith equation to calculate the calorie needed for the evaporation of plant and realized the temperature reduction effectiveness by the evapotranspiration in the high temperature urban area via Computational Fluid Dynamics simulation. The results show that the planting has significant influence on the urban temperature reduction and the evapotranspiration of plant can ease off the urban high temperature situation. While under a windless condition, in compare with a windy environment which has better temperature reduction effect, the heat is difficult to dissipate due to the static status of the wind field. With regards to buildings, heat tends to accumulate at the windward and lee side of the building by eddy effect. For the future urban design code, the wind directing by plant and the ventilation of pedestrian wind field shall both being considered to alleviate the high temperature situation.