The Research On Cooling Effect Of Urban Green Space In Harbin Based On Mitigating Hrat Island Effect

Global warming,heat island effect is increasingly evident.Heat island effects can cause extreme weather to seriously affect people's health and increase energy consumption and other negative effects.Increasing the urban green space has proven to be the most effective way to slow down the heat island.In order to cope with the increasingly severe heat island problem,it is urgent to combine the urban green space to improve the heat island effect.With global warming,heat island effect is getting increasingly evident.Heat island effects can cause extreme weather witch can seriously affect people's health,increase energy consumption and bring other negative effects.Increasing the urban green space has been proven to be the most effective way to mitigate the heat island.In order to cope with the increasingly severe problem caused by heat island effect,it is urgent to perform the research on improving heat island effect combining the urban green space.Taking Harbin as an Example to study the cooling effect of urban green space based on heat island effect in severe cold region.Using the remote sensing technology and data analysis method,and using Landsat series images as basic data,the variation of the vegetation information was carried out,and the temporal and spatial evolution characteristics and ground feature changes of summer and winter in Harbin were summarized.It is found that the summer heat island effect in Harbin is obvious,and the trend is increasing with each passing year.Heat island effect in winter has not formed yet but there is a trend to a certain degree;green space area decreased year by year,and the reduction rate is decreasing.The underlying surface changes in winter,which is covered by snow with no plant except the construction area.Based on the analysis of heat island and green land change,the vegetation index and surface temperature information were extracted by grid method,and the relationship between urban green space and heat island was analyzed quantitatively.The study shows that the urban green space in Harbin has the effect of cooling and slowing down heat island effect in winter and summer.In the winter,there is still some cooling effect in urban green space whether there is no snow-covered or little snow-covered,but there is no correlation between urban green space and heat island effect in the area mainly covered by ice and snow.Based on this,a total of 32 study plots were selected to analyze the cooling range,amplitude and maximum temperature change.It was found that the coolingeffect of urban green space was significant in summer,the average cooling temperature was 1.65?,the average maximum temperature change was 7.5 ?,and the cooling range is mainly 120 m.The average temperature drop in winter is0.48 ?,the average maximum temperature change is 4.25 ?,and the cooling range is mainly 90 m.The factors influencing the cooling effect of green and summer in winter and summer were studied,and the influence of external factors was avoided as far as possible.Statistical analysis of the cooling range and amplitude found that the difference between the different plots is huge,which indicates that the green space has a great impact on cooling.The relationship between the green space shape,the area and the cooling distance of the green space and the cooling rate have been studied.The result shows that the green area and perimeter are logarithmically correlated with the cooling range,the temperature reduction rate and the maximum temperature change inside and outside the green space.The shape coefficient is exponentially correlated to the summer cooling range and the amplitude and the maximum change of internal and external temperature.In winter,the cooling effect is affected by the change of the main heat source and the cooling mode.The cooling range is influenced by the distance between the green space and the surrounding building and the building property,but it has no obvious correlation with the area circumference and the shape factor.The relationship between the area circumference,the shape factor,the temperature reduction rate,and the maximum temperature change is same with that in summer.This paper analyzes the effect of green space on the cooling effect in winter and summer,and explores the influence of urban green space on microclimate and the strategy of using green space to improve heat island.This paper analyzes the existing data and combines the cooling effect of Harbin green space,and finds that the effect of greening can be improved by controlling green space area,perimeter and shape coefficient.Increasing the green area(within 37ha)or the green circumference(within 5300m)can most economically improve its cooling effect.The simpler the green space shape is,the more obvious the cooling effect will be.During the design and expansion of urban green space,the shape factor should be controlled within 0.03.When it is greater than 0.03,changing its shape has little effect on the cooling effect.