Quantifying the impact of landscape pattern on land surface temperature: an integrated landscape index from perspective of scale response and threshold effect

Abstract

Urbanization-induced modifications to landscape pattern and process significantly contribute to urban heat island (UHI) intensification. Thus, optimizing urban ecoloigcal landscape pattern has consequently emerged as the nature-based solution (NbS) of UHI effect. However, an integrated index that comprehensively characterizes the ecological landscape pattern, as well as can be practically applied to urban planning still requires further development. Here, we proposed an integrated index, the ecological landscape index (ELI), aiming to quantify the impact of the ELI on urban land surface temperature (LST) from the perspective of scale response and threshold effect, as well as provide actionable knowledge for UHI mitigation based on ELI regulation in Shanghai, China. The results indicated that the ELI showed excellent performance and scale-dependent in determining LST variation. In addition, the grid size of 3120 × 3120 m (G₃₁₂₀) was identified as the optimal and practical grid scale for implementing urban ecological landscape planning strategies targeting UHI mitigation. The ELI difference accounted for 84 %-91 % of LST variation, and with a 0.1 decrease in ELI predicted an increase in LST by exceeding 1.72 ℃ in three selected dates. Moreover, the ELI value of 0.16 and 0.44 were determined as threshold sizes of the hot temperature zone (HTZ) and cold temperature zone (CTZ), respectively, i.e., when the specific grids with ELI value below 0.16 were more likely to be HTZ, while those above 0.44 tended to be CTZ in theory. These findings are essential to decisionmakers and can provide actionable knowledge for UHI mitigation and climate adaptation from the perspective of urban ecological landscape optimization.