基于景观格局与累积影响的城市公园降温效益研究——以南京为例

Assessing Urban Park Cooling Effects Through Landscape Patterns and Cumulative Impacts:Case Study of Nanjing City

城市公园能够发挥其“冷岛作用”,全面认识城市公园的降温效益可以有效缓解城市热岛效应,提高城市对气候的适应性。以南京市25个城市公园为研究对象,以2个最大影响指标:公园降温面积、降温效率和2个累积影响指标:公园降温强度与降温梯度,对公园降温效益进行综合研究。结果表明:(1)城市公园具有显著的降温效益,能够使周边环境温度降低0.16℃~2.28℃。(2)相关性分析表明,公园降温面积与PP、PA、NDVI呈显著正相关,公园降温效率与PP、PA、LSI呈负相关;公园降温强度和梯度与NDVI呈显著正相关,与PP、PA呈正相关。4项降温指标与MNDWI的相关性均不显著。(3)不同类型公园的降温效益具有差异性。专类公园或社区公园更适合建在城市用地紧张区域,综合公园在建设时应多考虑边界复杂情况及植被情况,以充分发挥降温效益。研究结果有助于未来城市公园的建设与优化,有效应对城市热岛效应。

Urban parks can play the role of“cooling islands”.A comprehensive understanding of the cooling benefits of urban parks can effectively alleviate the urban heat island effect and improve the adaptability to climate change.Taking 25 urban parks in Nanjing city as the research object,this paper conducted a comprehensive study on the cooling benefits of parks with two maximum impact indicators of park cooling area,cooling efficiency and two cumulative impact indicators of park cooling intensity and cooling gradient.The results showed that:(1)The urban park had a significant cooling effect,by reducing the ambient temperature by 0.16℃-2.28℃.(2)The correlation analysis showed that the park cooling area was significantly positively correlated with PP,PA and NDVI,and the park cooling efficiency was significantly negatively correlated with PP,PA and LSI.The cooling intensity and gradient were positively correlated with NDVI,PP and PA.The correlation between the four cooling indexes and MNDWI was not significant.(3)Different cooling benefits were shown for different types of parks.Special parks or community parks were better fitted to the areas of tight land use.Construction of comprehensive parks should take more consideration of complex boundary conditions and vegetation conditions to maximize the cooling benefits.This study was expected to guide the construction and optimization of urban parks in the future,to effectively respond to the urban heat island effect.