Exploring the potential relationship between cooling green space and built-up area: Analysis of community green space characteristics based on GWPCA

Abstract

Rapid urbanization exacerbates urban heat island (UHI) problem. Although urban green space (UGS) can produce multiple benefits for mitigating UHI, the accompanying problems of urban development cause multiple pressures on greenery. Therefore, the pattern of green spaces should be adjusted to adapt to the current situation of the built-up area, fully utilizing its cooling effect, which is of great significance for achieving sustainable and balanced urban development. We selected 849 community units in Harbin city for the study, calculated the urban green space pattern index (UGSP) based on geographically weighted principal component analysis (GWPCA), And used bivariate choropleth map and Cartesian coordinate system to explore the spatial relationship between UGSP and associated characteristics of urbanization (e.g., land function diversity and development intensity). The results showed the following. (1) Compared with traditional PCA, GWPCA can capture local details of UGSP, especially proportion of tree area was the most sensitive factor in the urban core area, and FRAC_MN and LSI were the sensitive factors in the west and south of urban outer areas, respectively. (2) The matching degree between development intensity (I) and UGSP was slightly better than that between land function diversity (D) and UGSP, and showed a more egalitarian phenomenon. (3) The equilibrium value (d_Low) presented a relatively random spatial distribution when UGSP was less than D/I, and the unbalanced value (d_High) was scattered in the core area. Both d_Low and d_High were concentrated outside the urban core area when UGSP was greater than D/I. Our study provides an effective guidance for community greenery to mitigate UHI and realize the harmonious coexistence between city and nature.