The Evaluation for City Greening Land Construction to Mitigate the Heat Island Effect in Shanghai

摘要

First the evolution and situation of heat island in Shanghai area are summarized , and the question of how mitigating the heat island effect is put forward. Based on the dense observation data inside and outside Yang - Zhong greening land in recent three years, the mitigation for greening land construction to heat island effect is evaluated. Meanwhile a cylindrical model to estimate the effect of decreasing temperature of Yang-Zhong greening land is designed. The comparison of the monthly mean maximum temperatures indicates that in summer the greening land can reduce the temperature as much as 0. 6℃ , the temperature difference between inside and outside greening land exists seasonal fluctuation, the middle value of the seasonal fluctuation tends negative, it is resulted from the different thermal capacity between inside and outside of the greening land and the effect of shading and evaporation of plant leaves. With expending and glowing of the Yang-Zhong greening land, the heat island intensity of the greening land itself is decreasing. In recent three years the extensive construction of city greening land has mitigated the heat island intensity in the central city zone in the range of 0. 2 — 0. 4℃ of the monthly mean maximum temperatures in summer.