| With the continuous acceleration of my country’s urbanization,the problem of urban thermal environment has become increasingly prominent.The urban blue and green space system from the perspective of thermal environment improvement has attracted the attention of scholars at home and abroad.From the perspective of blue and green space landscape components and spatial configuration,many studies have been carried out on the thermal environment,but there are still key landscape pattern indexes.Not yet clear and other shortcomings.Taking the six districts of Tianjin as an example,based on technologies such as satellite remote sensing images,geographic information systems,and landscape pattern analysis,this paper studies the mechanism of urban blue and green space system on the thermal environment,and builds a systematic evaluation system to guide the blue and green space System ecological pattern planning.First,with the help of ENVI,the satellite remote sensing image maps of the six districts of Tianjin in the summer of 2004,2011,and 2017 were used to retrieve the surface temperature and interpret the blue and green space classification,and establish a geographic information database based on the GIS platform.By analyzing the temporal and spatial evolution characteristics of the land surface temperature and the blue and green space system,it is found that the two are closely related: the hightemperature area is continuously expanded with the direction of urban construction and the spatial restriction across the river boundary;while the low-temperature area is mainly concentrated in the city Parks,protective green spaces,lakes,rivers and other blue and green spaces.Then,from the patch and type of landscape pattern,the preliminary indicator database of urban blue and green space system from the perspective of thermal environment improvement was established.Fragstats was used to calculate relevant indicators for the blue and green space in the six districts of Tianjin in 2017.The SPSS platform constructs a regression model of land surface temperature and patch indicators inside the blue and green space,and a regression model of land surface temperature and type indicators of multi-scale sub-landscape research samples.The analysis found that the surface temperature inside the blue and green space is negatively correlated with Patch Perimeter(PERIM)and positively correlated with Perimeter-Area Ratio(PARA);the best fit scale of the blue space sample is1500m×1500m,and the surface temperature is related to Percent of Landscape(PLAND),Largest Patch Index(LPI),Patch Area＿Mean(AREA＿MN),Edge Density(ED),and Patch Density(PD)are negatively correlated;the best fit scale for green space samples is 300m×300m,the land surface temperature is negatively correlated with Percent of Landscape(PLAND),Largest Patch Index(LPI),and Patch Area＿Mean(AREA＿MN),and positively correlates with Patch Density(DIVISION).The evaluation system of the blue and green space system in the six districts of Tianjin from the perspective of thermal environment improvement was determined.Finally,based on the above analysis results,focusing on the current situation,the blue and green space system planning strategy of “four axes,one ring,multiple corridors,and multiple nodes” is proposed for the six districts of Tianjin.Special upgrades will be carried out in four aspects: strictly protecting the existing status quo,expanding the area and marginal indicators,building a multi-level cooling core,and increasing the patch density of planar water bodies. |
