Mapping urban morphology changes in the last two decades based on local climate zone scheme: A case study of three major urban agglomerations in China

Urbanization has been bringing extensive land use and land cover change over the last several decades, which has an impact on the urban climate and also further affects public health and energy consumption, due to human activities. The local climate zone (LCZ) classification system was proposed in 2012 to depict the complexity of urban morphology. However, until the present, LCZ long-time series product was rarely seen for its mapping difficulty. This study proposed a framework for mapping annual LCZ time series with spatial-temporal consistency in the three major urban agglomerations in China and the temporal and spatial pattern of LCZ time series was also revealed. The result showed that the high-rise and open urban LCZ types tended to occupy higher proportion in the urban area in the past two decades and urban morphology varied much in urban expansion areas and urban renewal areas. From 2000 to 2020, the differences in urban morphology between the three urban agglomerations and urban areas of different urban sizes narrowed, but the differences between urban areas with different land uses widened.