Characterizing dynamics of building height in China from 2005 to 2020 based on GEDI, Landsat, and PALSAR data

The unprecedented urbanization in China has driven rapid urban and rural development in recent decades. While existing studies have extensively focused on horizontal urban expansion, research on vertical urban expansion patterns in China remains limited. To address this gap, we proposed a Multi-Temporal Building Height estimation network (MTBH-Net) to estimate building heights at a 30 m spatial resolution in China for 2005, 2010, 2015, and 2020 by integrating Global Ecosystem Dynamics Investigation (GEDI), Landsat, and PALSAR data. Specifically, we introduced sample migration to generate reference building height data and utilized the Continuous Change Detection and Classification (CCDC) disturbance feature to ensure consistency in unchanged built-up areas. Validation with GEDI L2A V2 data demonstrated that MTBH-Net achieved RMSEs of 5.38 m, 5.73 m, 6.26 m, and 6.36 m for the respective years. Further validation with field-measured data and GF-7 building height data yielded RMSEs of 9.13 m and 10.99 m, respectively. The proposed 30-m China Multi-Temporal Building Height (CMTBH-30) dataset reveals an increase in average building heights in China from 10.48 m in 2005 to 11.37 m in 2020, reflecting an upward trend in urban development. Additionally, the standard deviation of building heights rose from 3.87 m in 2005 to 6.35 m in 2020, indicating increased height variation nationwide. Regional analysis from 2005 to 2020 shows notable vertical growth on newly expanded impervious surfaces in Macau (+14.9 m), Hong Kong (+13.9 m), and Guangdong (+13.5 m), while Chongqing (+3.6 m), Guizhou (+3.0 m), and Qinghai (+3.0 m) also experienced significant growth on stable impervious surfaces. Minimal growth was observed in Jilin, Heilongjiang, and Xinjiang. CMTBH-30 offers a more refined and accurate depiction of building heights, effectively capturing height variations and mitigating the underestimation of high-rise buildings. It fills the gap in multi-temporal building height estimation. Overall, this study provides a new dime