Scale effect of regulating mechanism of urban water bodies in improving thermal environment in Wuhan,China
It is of great significance to understand the regulation mechanism of urban water bodies on thermal envi-ronment for developing urban blue-green infrastructure system oriented to thermal environment improvement.This study detected the correlations between commonly-used landscape metrics and land surface temperature(LST)at different scales of 300 mx300 m,1000 mx1000 m,and 3000 mx3000 m.The main influencing factors of water bodies in regulating thermal environment were identified and the regulation mechanisms were monitored accordingly.The results showed that:(1)Generally,LST was more stably and closely correlated with the landscape indices at class level than with those at landscape level.(2)At class level,the correlations between LST and the variables indicating water area,proximity and dispersion were stable and less affected by scale size,while those related to density,shape and edge characteristic of water bodies were scale-dependent.The variables at landscape level showed stronger correlations with LST with the increases of scale size,thus they were appropriate to explain the LST variation at a larger scale.(3)The main influencing factors and mechanism of water bodies on cooling thermal envi-ronment varied with scale size,showing an obvious scale effect.The area proportion of water bodies in landscape was the largest contributor to the cooling effect of water bodies at all studied scales,though the relative contribution decreased with the scale increasing.Additionally,the cooling effect of water system was influenced by water body shape and edge features at local scale(300 m)and by the proximity and distribution distance of water bodies at coarser scale(3000 m).(4)Considering the interactions between water bodies and other landscape elements,LST variation at local scale was mainly attributed to the area and spatial distribution distance of construction land.The cooling efficiency of water bodies was weakened by the surrounding impervious covers.At coarser scales,the area proportion of water bodies in landscape contributed more to thermal environment variation,which could combat the thermal deterioration caused by urbanization to a certain extent.These findings provide informative evidence for the planning of urban blue-green infrastructure system to adapt to climate change.
heat island effectblue-green infrastructurecooling effectlandscape metrics
国家科技期刊平台
NSTL
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