Effects Of Plant Spatial Structure On Microclimate In Summer And Winter In Different Residential Areas

This article was through a large number of field surveys,temperature and humidity measurements,combined with human comfort evaluation indicators,focused on the effect of plant space structure under different architectural layouts on the temperature and humidity microclimate in residential areas.By investigating and analysing the urban climates in Nanchang City,the types of architectural layouts in residential areas and the plant community profile of residential areas,three types of typical architectural layouts were selected: determinants,hybrids and enclosures.Four types of plant communities were selected as the research objects: arbor-shrub-grass structure,arbor-grass structure(lawn with few trees),shrub-grass structure and lawn structure,which were quantified.From July to August in 2017,December in 2017 to January in 2018,field measurements of temperature,humidity and wind speed in summer and winter were carried out,an optimization strategy for coordinating the environment of residential areas in summer and winter was proposed.The main conclusions were as follows:(1)When the canopy density of plant communities was below 0.4 in summer,the NTHI value increased slowly;the human body feeled more comfortable as the canopy density was from 0.6 to 0.8.When the canopy density reached 0.9,the comfortable degree of human body decreased.When the weather in winter was cloudy and the canopy density was above 0.8,the temperature in the arbor-shrub-grass community was higher than the temperature in the open area.(2)In summer,when the green space was arbor-grass structure(lawn with few trees),the canopy density of the plant community was in the range of 0.6~0.8 and the proportion of trees within the plant community was 45%,the NTHI value was the maximum.(3)In sunny winter,under the condition that the aspect ratio of the building was in the range of 1~2,the temperature and humidity index of the human body was significantly correlated with the light intensity.In cloudy weather,the correlation between light and the comfortable degree of human body was not significant.(4)The plant community structure which made human body feel uncomfortable in both summer and winter was the arbor-shrub-grass structure with the canopy density greater than 0.8,small arbor-shrub structure with the canopy density below 0.35 and shrub structure without tree layers,such as the sample plot 2,a osmanthus trees array square in Liantai Xiangyu Shang cheng,sample plot 4 in Oaks flourishing classic and measuring point 4 in Red Valley Spring Garden.The arrangement of plants in summer and winter which can provide comfortable body feeling was canopy density in the range of 0.4~0.8.The plant community structure was a sparse forest with a arbor-shrub-grass structure or a structure of deciduous tree array square that the canopy density in the range of 0.6~0.8.The characteristic of comfortable plant community in summer was the plant canopy density in the range of 0.6 ~ 0.9,and the community structure was arbor-grass,arbor-shrub-grass structure.The characteristic of comfortable plant communities in winter were the arbor-grass,deciduous pure arbor structures and semi-enclosed turf greens with summer canopy density below 0.4.(5)With the reference of wind speed was 1.6~3.3m/s,the wind speed of the arbor-shrub-grass community structure and the open grassland diferred 0.61m/s when the canopy density above 0.8 in residential area.For example,the measured wind speeds were all relatively small in these: plot 4 in the Oaks flourishing classic,plot 4 in the Red Valley Spring Garden and plot 2 in the LuJing Famous Residence.The measured wind speeds were relatively large in these plots which were the Oaks flourishing classic plot 1,plot 5,and the LuJing famous residence measuring point 3.(6)In cloudy winter,there was a significant correlation between the human temperature,humidity index and wind speed.When the weather was sunny or cloudy,and the wind speed in the residential area was below 1 m/s,there was no significant correlation between the human temperature,humidity index and wind speed.There was a significant correlation between wind speed and improving human body comfort in the full line layout.