[Mechanisms of Three-dimensional Urban Morphology of Urban Block on Carbon Emissions]

Urban blocks are the basic unit of urban planning and fine management of carbon emissions. Investigating the interplay between urban morphology and carbon emissions holds notable implications for achieving carbon peak and carbon neutrality targets, as well as for urban sustainable development. However, most of the current research focuses on the regional and urban scales, and the influence mechanism of three-dimensional urban morphology on carbon emissions at the urban block scale remains unclear. Taking the main urban area of Hangzhou as an example, this study first estimated the spatial distribution of total urban carbon emissions at the scale of urban blocks by integrating nightlight, land use, and energy consumption data. Then, we calculated and superimposed the three-dimensional urban morphology indicators of these blocks and employed multiscale geographically weighted regression （MGWR） to explore the impact of block three-dimensional urban morphology on carbon emissions. The results showed that： ① The total CO₂ emissions from urban blocks in Hangzhou's main urban area were 50.88 million tons, with an average CO₂ emission intensity of 30 456.49 t·km^-2 in 2020. ② The three-dimensional urban morphology of blocks exhibited four spatial distribution patterns： cohesive ring-layer pattern, outer high-inner low pattern, ring distribution pattern, and south high-north low pattern. This indicates that the central area of Hangzhou's main urban area had higher spatial compactness, whereas the outer areas exhibited greater spatial irregularity and complexity in buildings. ③ Spatial extension and spatial irregularity had a positive effect, whereas spatial complexity had a negative effect. Spatial compactness had a dual effect on carbon emissions.