Urbanization is a major source of carbon emissions. A quantitative study on the dynamic relationship between urbanization and its morphological characteristics and carbon emissions is crucial for formulating urban carbon emission reduction policies. Based on the carbon metabolism model, the carbon emissions at the country level in Chang-Zhu-Tan from 1995 to 2020 were calculated. The Tapio decoupling model was used to explore the decoupling relationship between the carbon emissions of Chang-Zhu-Tan and urban land, and a geographically and temporally weighted regression(GTWR) model was used to analyze the impact mechanism of urban spatial morphology on carbon emissions. The following conclusions were drawn:① carbon emissions at the county level in the study area formed a clustered distribution centered on the city jurisdiction and showed a trend of diffusion from year to year. Compared with those in 1995, there were seven new high carbon emission districts in 2020, all of which belonged to Changsha. ② From 1995-2020, the research area as a whole changed from mainly strong decoupling to mainly dilated negative decoupling, and the spatial decoupling state fluctuated back and forth between the decoupling and negative decoupling. By 2020, except for the seven regions with the uncoupling state regressing, all of them reached the uncoupling state or were close to the uncoupling state. ③ Urban patch area(CA), urban patch number(NP), and patch combination degree(COHESION) were positively correlated with urban carbon emissions, whereas landscape shape index(LSI), maximum patch index(LPI), and Euclidean distance mean(ENN_MN) were negatively correlated with urban carbon emissions, and the impact of different urban form indicators on carbon emissions had significant spatial heterogeneity.
Keywords: county level carbon emissions; decoupling analysis; geographically and temporally weighted regression(GTWR); urban expansion; urban spatial form.