Comparison of the global map of local climate zones (LCZs) and GIS-based LCZs: A case study of two Japanese cities

The Local Climate Zone (LCZ) classification system has been widely applied across diverse fields of urban climate research. In particular, the Global LCZ map, developed using remote sensing-based methods, provides a global dataset of LCZs and has been utilized in numerous studies. However, existing accuracy assessment methods have limitations, and there has been little verification regarding the extent to which this LCZ map accurately represents the morphology of actual cities, especially in regions with complex urban forms. This study aimed to quantitatively evaluate the accuracy of the Global LCZ map in Japanese cities using field surveys and visual inspections, and to compare this accuracy with that of a Geographic Information System (GIS)-based LCZ map. The GIS-based LCZ map was created using the high-quality Japanese 3D GIS data, “PLATEAU,” provided by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT). The Global LCZ map's agreement with the field survey results was only 33% in Osaka and Shizuoka. The Global LCZ map struggled to accurately classify Japan's complex urban morphology, particularly in identifying building heights and land use (building function), resulting in its low accuracy. In contrast, the GIS-based method utilizing PLATEAU achieved an agreement of 81% with the field survey results in Osaka and Shizuoka. This result demonstrated that the GIS-based LCZ map exhibits significantly higher accuracy compared to the Global LCZ map. This study offers researchers a deeper understanding of the strengths and limitations of the Global LCZ map.