Application Of Nanjing City Piazza Temperature And Humidity

It is of great significance to study the micro climate characteristics of urban piazza and its influencing factors in guiding the design and construction of urban piazzas and improving the quality of outdoor space environment.The research is based on the thinking of measurement-simulation-practice.First,the author choose six city piazzas in Nanjing:Hanzhongmen piazza,Xi'anmen piazza,Gulou piazza,Daxinggong piazza,Kazimen piazza and Hepingfazhi piazza,then measured air temperature and humidity in different plants shading and surface types in summer,autumn and winter,and explored the influence of factors of temperature and humidity in city piazza;secondly,author used the measured data to test the reliability of ENVI-met software to simulate the temperature and humidity of piazza micro environment;finally,based on the ENVI-met micro climate simulation software,We have carried out the local micro climate reconstruction design for the Kazimen piazza.The main research contents and conclusions are as follows:The research choose four kinds of measuring points in each piazza:respectively:hard without shading(control points),hard shading,soft without shading and soft shading;in the summer autumn and winter sunny day,we measured and recorded the temperature and humidity of six piazzas 1.5 meters high,measuring time was 8:00-18:00,then analyzed the influence of the material and shading on the temperature and humidity in the three seasons.The results showed that plant shading in summer had a significant effect on the temperature and humidity,while the effect was weakened in autumn and winter;Soft surface often has significant cooling and humidifying effect in summer,but the influence in autumn and winter usually was not significant;Under the condition of soft underlying surface,the effect of cooling and humidifying of plant shade was stronger;Compared with the underlying surface,the plant shading had better temperature and humidity regulation effect.Based on the investigation of plants in 6 piazzas in Nanjing,We analyzed the correlation between plant living vegetation volume in the range of 10 meters and summer temperature and humidity.The results show that the amount of living vegetation volume surrounding the station within 10 meters are significantly related to measuring point cooling and humidifying rate,the absolute value of the correlation coefficient between 0.78--0.98,the more community living vegetation volume,the better effect of cooling and humidification.The study chose Kazimen piazza as a typical case,based on distribution of temperature and humidity in the three seasons,which was simulated by ENVI-met software,and compared simulated data with actual measurements to verify the feasibility and accuracy of the software;The results show that the relative error of simulated temperature was within 5%in summer and autumn and the humidity was less than 13%,which the accuracy was higher,and the winter error was larger,so software was more suitable for the summer and autumn season environment simulation.Finally,combined with ENVI-met simulation and field research to find the uncomfortable and low utilization area to transform,we proposed transformation strategy:establishing a reasonable plant community,choosing permeable materials,creating a different function of space,adjusting the proportion of soft and hard under the surface.at last,we used software to verify the micro climate after modification.The study on clearing the affecting factors of piazza micro-climate,exploring the application methods,advantages and disadvantages of ENVI-met software in micro parametric design of landscape architecture,raising the micro-climate design level of Landscape Architecture,has a certain reference value.