Influence Of Different Greening Methods On Road Microclomate In Lin’an District,Hangzhou

Green land is the main factor to improve urban microclimate.Different greening methods can change the road microclimate.Therefore,in order to explain the reason,the mircroclimate in Nonglinda Road,Lintian Road,Qianjin Avenue,Wusu Street,Tiaoxi South Street,Yijin Street and Zhongcheng Street in Lin’an District of Hangzhou was detected,and the microclimate parameters such as solar radiation intensity,air temperature,relative humidity,surface temperature,black ball temperature,wind direction and wind speed respectively were measured,and the physiological equivalent temperature(PET)was calculated.All results as following:1.The microclimate parameters of various plots are analyzed,the increase and decrease rates of each microclimate parameter are calculated to compare the strength of different road greening on microclimate improvement.Among the north-south sample plots,Y-2 greening has the strongest regulating effect on solar radiation intensity(reduction rate 90.52%),relative humidity(growth rate27.4%),surface temperature(non-motorized lane reduction rate 28.29%,sidewalk reduction rate22.55%);Sample plot Y-3 has the strongest effect on air temperature regulation(the reduction rate is9.13%).Among the east-west sample plots,sample plot Y-6 has the strongest regulating effect on solar radiation intensity(reduction rate 91.56%),air temperature(reduction rate 8.53%),relative humidity(growth rate 20.47%),surface temperature(non-motorized lane reduction rate 31.58%,sidewalk reduction rate 28.39%).Physiological equivalent temperature(PET)is calculated as an evaluation index of road microclimate environment.The results show that the tree shading effect of Y-2(PET reduction rate 38.66%)and Y-6(PET reduction rate 38.90%)is better in the north-south sample plot and the east-west sample plot,and the amount of Green land is larger,which has obvious improvement effect on road microclimate.2.Through analysis,it is concluded that crown diameter and branch and leaf density are the main factors that block solar radiation and reduce surface temperature.Abundant greening structure and appropriate road green amount play an important role in reducing road air temperature and increasing relative humidity.The closed green land structure can reduce the wind speed in the road space.Based on the above measured research results,the optimization strategy of road greening is proposed.When the current road situation allows,more green belts should be added as much as possible.Street trees shouldchoose tree species with large crown and thick shade,with deciduous trees combined with evergreen trees being the best,and the planting spacing should be equal to or slightly less than the crown diameter of adult tree species.The longitudinal configuration of plants should be mainly arbor-shrub-grass,but the influence of the tightness of Green land structure on wind speed should be considered.The application of vertical greening and roof greening should be increased.