Correlation Mechanism Between Parks'Cold Island Effect and Landscape Characteristics under Different Urban Heat Island Gradients
The cold island effect created by urban parks has become one of the important ways to alleviate the urban thermal environment.Using Landsat 8 OLI-TIRS and Google Earth remote sensing data,the paper inverted the surface temperature of 22 parks in Jinan City by means of a radiation transmission algorithm.The methods of buffer zone analysis,multiple statistics,and correlation analysis are adopted to quantify and analyze the relationship between the average temperature inside the parks,parks'cold island effect,the internal mechanism of parks,and two landscape features of urban morphology.The contribution of landscape characteristics is initially investigated using the growth regression tree model.The study finds:1)The park cold island effect presents the gradient changes under the different heat island gradients in the city.The park with higher level of heat island effect has the largely significant cold island effect;2)When park area reaches 200 hm2,water bodies reach the area of 45 hm2,and the green area is between 80 and 100 hm2,the best cool island effect of parks can achieve,while water bodies have better cooling effect than green spaces;3)The correlation between the building height and the cold island effect is extremely significant.When buildings are 35-63 m high,the maximum cooling distance increases with the building height,and the overcrowded and disorderly buildings will not give play to parks'cold island effect;and 4)The internal mechanisms have greater contributions to park surface temperature,maximum cooling distance and cooling intensity than the external index of urban morphology,but urban morphology has a greater contribution to the cooling gradient.Hence,it is suggested that,under different urban heat island gradients,the thermal environment around parks as well as the human comfort could be improved through controlling the area of green spaces and water bodies in parks within the threshold,appropriately complicating park contours and increasing the impermeable area,and using urban wind corridors to make more cool air overflow.
heat-island effectcity parkcold island effectsurface temperature of parkJinan City
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NSTL
万方数据
