Monitoring periodically national land use changes and analyzing their spatiotemporal patterns in China during 2015-2020

High-resolution mapping and monitoring of national land use/cover changes contribute significantly to the knowledge of the interaction between human activities and environmental changes. China's Land Use/cover Dataset (CLUD) for 2020 and its dynamic changes in 2015-2020 were developed to extend the CLUD to over 30 years (i.e., the 1980s to 2020 at 5-year intervals) by integrating remote sensing big data and knowledge-based human-computer interaction interpretation methods. This integrating method for CLUD 2020 improved the efficiency of national land use/cover mapping and the accuracy of land use pattern change detection compared to earlier CLUD products, with an overall accuracy of 95%. The intensity of land use change decreased across China in 2015-2020 compared to 2010-2015, although both characteristics of its spatial changes were similar. The cropland area continued to shrink at national scale in 2015-2020, with two regional hotspots including the widespread conversions from dry land into paddy land in Northeast China and the coexistence of widespread land cultivation and cropland abandonment in Xinjiang of Northwest China. Built-up land area continued to expand in China, showing consistency between 2015-2020 and 2010-2015, in which hotspots transited from the surroundings of coastal megacities to the city surroundings of the central and western zones. For natural land, although the woodland and grassland decreased in 2015-2020, its magnitude expanded compared to 2010-2015. In comparison, the water body area in Qinghai-Tibet Plateau increased significantly under the continuous impact of climate change. These characteristics of land use change were closely related to the development strategy of the top-level design of the 13th Five-Year Plan (2016-2020) (e.g., ecological civilization construction and high-quality development).

Automated summary

High-resolution mapping and monitoring of national land use/cover changes play a significant role in understanding the interaction between human activities and environmental changes. China's Land Use/Cover Dataset (CLUD) provides data for nearly 30 years, using remote sensing big data and knowledge-based interpretation methods to improve the efficiency and accuracy of national land use/cover mapping. From 2015 to 2020, the intensity of land use change in China decreased, with a continued decrease in cropland area and an expansion of built-up land area. The woodland and grassland decreased in natural land, while water body area increased significantly in the Qinghai-Tibet Plateau. These changes are closely related to development strategies.