Using buffer analysis to determine urban park cooling intensity: Five estimation methods for Nanjing, China.

Area of Science:

• Urban Ecology
• Environmental Science
• Geographic Information Science

Background:

• Urban parks are crucial blue-green infrastructure components in cities.
• The cooling effect of urban parks is recognized, but park cooling intensity (PCI) and its mechanisms require further understanding.
• Accurate PCI quantification is vital for effective urban park design and management to combat urban heat island (UHI) effects.

Purpose of the Study:

• To compare five methods for estimating PCI and establish a method selection mechanism.
• To analyze the spatial heterogeneity of PCI and its relationship with park landscape features.
• To provide insights for landscape planners to design cooler urban parks and mitigate UHI.

Main Methods:

• Employed five distinct methods: equal area method (EAM), equal radius method (ERM), fixed radius method (FRM), turning point method-maximum perspective (TPM-M), and turning point method-accumulation perspective (TPM-A).
• Utilized spatial and statistical analyses in Nanjing as a case study.
• Evaluated PCI amplitudes, spatial heterogeneity, and interactions with park landscape features.

Main Results:

• 62.38% of Nanjing's urban parks are situated in cold spot areas (above 90% confidence level).
• Different PCI estimation methods showed significant positive correlations and similar spatial heterogeneity.
• Park area (PA), water area proportion (WAP), and vegetation NDVI (NDVI_veg) were dominant factors influencing PCI, with WAP and NDVI_veg yielding more effective cooling.

Conclusions:

• The ERM and TPM are recommended for quantifying PCI due to their effectiveness.
• Understanding PCI formation and influencing factors is essential for systematic UHI mitigation strategies.
• This research aids landscape planners in designing more effective cooling urban parks.