Study On The Outdoor Thermal Environment Experimental Effects Of Green In Summer

Urban greening is an important part of urban construction. Greening, as one of the most economical and effective means to improve urban thermal environment, can take effect on urban thermal environment in improving regional micro-climate, easing the urban heat island effect, balancing urban ecosystem and improving the urban living environment and so on. This article analyzed the status of the impact of greening on outdoor thermal environment and summarized the disadvantages of the research methods and applications, To solve these problems, the report, taking the Xi'an city green tree in summer as an example, studied and carried out:Firstly, the paper analyzed the theory and mode about the influences of the green on thermal environment, classified the plants from the perspective of the thermal environment, and especially analyzed of effects on the urban thermal environment on different plant biological factors in the different climatic conditions which the computer simulation can't display. In this research, the common city trees could be divided into five typical patterns, which may provide the basis of options for the green design.Secondly, taking Xi'an City as a case, the study selected optimized representative species in different forms, measured physical parameters of selected subjects in practice, and obtained thermal environmental indicators data and change curve of different trees, analyzed the influence of outdoor thermal environment by the different physical characteristics of trees. The study selected the wet globe temperature WBGT as the evaluation index of outdoor thermal comfort and evaluated thermal comfort of different trees. The experiments showed that the trees improve micro-climate better than the grasses; the wind speed around the tall trees is higher than it with the low trees; the trees of large LAI affect the temperature greater than the trees with small LAI, reversed pyramid-type crown improves more areas for thermal environment than other bigger crowns.Thirdly, the study analyzed the correlation between computer simulation and experimental research. Experimental results showed the theoretical trends in the computer simulation and shortcomings of computer simulation. Compared with experimental and simulation results, both got a basically same conclusion, from a macro point of view, such as comparison of greening forms, green biomass and so on; The simulation can't study in-depth, from the biological viewpoint, such as comparison of urban green trees and crown, so it should take experimental results of the study as a reference.This thesis studied the forms and extent of effects on urban thermal environment by the urban greening by measurement, summarized the pattern of the trees impacting on thermal environment from the data, and provided a theoretical basis for improving urban green design and outdoor environment scientifically and rationally.