Impacts Of Landscape Composition And Configuration Of Residential Area On Temperature And Humidity

The acceleration of urban processes has led to the transformation of surface landscape composition from highly concentrated vegetation cover to scattered impermeable surfaces,thereby enhancing the urban heat island effect(UHI).The increase of temperature has a negative impact on human thermal comfort and public health,and will also increase building energy consumption and air pollution.Therefore,in order to improve the livability of residential areas,it is necessary to study the influence of surface landscape composition and configuration of residential areas on temperature and humidity.In this study,the Longhu residential area of Jiangbei District in Chongqing was taken as the study area,and the scope is 105hm~2.With the help of remote sensing satellite image map,the study area was divided into 420 basic grids of 50 m×50 m by systematic sampling,and then combined with field measurement,the relationship between the landscape composition and configuration of residential area and the effect of cooling and humidifying in residential area was analyzed in 3 seasons.Then,using adjacency lattice sample method,the grid size was expanded to 100 m×100 m、150m×150 m,200 m×200 m and 250 m×250 m,and the relationship between the landscape composition and configuration of residential area and the effect of cooling and humidifying in residential area at different grid scales,and the scale dependence of the relationship between them was further discussed.In addition,through systematic sampling,97 activity sites in the study area were investigated to explore the difference of microclimate between different shading conditions and paving materials.The results show that:(1)For the landscape composition,the proportion of pavement and the proportion of forest have a significant effect on the cooling and humidification effect.Increasing the proportion of forest and reducing the proportion of impervious paving can increase the effect of cooling and humidification.When the pavement ratio is reduced by 10%,the cooling and humidification ranges can be increased by up to 0.9℃and 1.4%,respectively.For every 10%increase in the proportion of forest,the air temperature reduction and humidity increase can be up to 1.0℃and 1.9%,respectively.(2)Completely and continuously distributed large patches of forest,small patches of broken and scattered pavement,and the uniform distribution of the area of landscape elements all have a promoting effect on the cooling and humidification effect of residential areas.For every 10%increase in the division index of woodland,the average cooling and humidifying ranges can be reduced by 3.2℃and 4.9%on average.Contrary to woodland,for every 10%increase in the division index of pavement,the average cooling and humidifying can increase by an average of 1.1℃and 2.1%.For every 10%increase in SIEI,the average maximum increase in the cooling and humidification can reach 1.7℃and 3.1%,respectively.(3)The relationship between landscape composition and cooling,humidifying effects is scale-dependent.For the proportion of landscape elements,the grid size of 200m×200 m is very critical,because in the linear regression results,R~2 usually shows a trend of first rising and then falling,and reaches the maximum at this scale.At this scale,the maximum explanation ability of the proportion of forest to the cooling and humidification effect can reach 76.8%and 69.8%,respectively,and the maximum explanation ability of the pavement ratio to the cooling and humidification effect can reach 74.7%and 67.5%,respectively.For the landscape configuration,the linear regression results of the forest’s division index on the cooling and humidification effect are poor,and the R~2is less than 0.100 in summer and autumn.The linear regression effect of the paved division index on the cooling and humidification effect is excellent,and showing scale dependence.However,the R~2variation law of SIEI on cooling and humidifying effect is not as good as the division index of woodland and pavement.(4)Compared with the shading area,the average intensity of illumination,air temperature,surface temperature and temperature difference between surface and air in the non-shading area are always higher.The temperature difference between the air temperature and the surface temperature can be up to 5.7℃and 10.6℃respectively.On the contrary,the air humidity in the non-shading area is lower than the shading area,and the maximum difference can reach 9.4%.Under different shading degrees,the maximum temperature difference between air temperature and surface temperature can reach 2.5℃and 4.1℃respectively(P<0.05),but the difference in humidity is not obvious(P>0.05).(5)With the same shading conditions,the air temperature and surface temperature of grass and wood are the lowest.The maximum temperature difference 2.7℃is found in wood and plastic,and the maximum surface temperature difference 5.7℃is found in grass and asphalt.Similarly,the temperature difference between surface and air,grass and wood are also the lowest,and the largest difference between paving materials occurs on grass and asphalt,which is 3.4℃.On the contrary,with the same shading conditions,the humidity on the grass and wood are always the highest.The largest difference in humidity 12.1%,occurs on wood and plastic surface.