Hierarchical Urban Land Mappings and Their Distribution with Physical Medium Environments Using Time Series of Land Resource Images in Beijing, China (1981–2021)

Abstract

Rapid urban expansion and structural changes are taking place in China’s capital city, Beijing, but without an update of urban land features in a timely manner our understanding of the new urban heterogeneity is restricted, as land-background data is indispensable for bio-geophysical and bio-geochemical processes. In this plain region, the investigations of multi-scale urban land mappings and physical medium environmental elements such as slope, aspect, and water resource services are still lacking, although Beijing can provide an exemplary case for urban development and natural environments in plains considering the strategic function of China’s capital city. To elucidate these issues, a remote-sensing methodology of hierarchical urban land mapping was established to obtain the urban land, covering structure and its sub-pixel component with an overall accuracy of over 90.60%. During 1981–2021, intense and sustained urban land expansion increased from 467.13 km2 to 2581.05 km2 in Beijing, along with a total growth rate of 452.53%. For intra-urban land structures, a sharp growth rate of over 650.00% (i.e., +1649.54 km2) occurred in terms of impervious surface area (ISA), but a greening city was still evidently observed, with a vegetation-coverage rate of 8.43% and 28.42% in old and newly expanded urban regions, respectively, with a more integrative urban ecological landscape (Shannon’s Diversity Index (SHDI) = −0.164, Patch Density (PD) = −8.305). We also observed a lower rate of ISA (0.637 vs. 0.659) and a higher rate of vegetation cover (0.284 vs. 0.211) in new compared to old urban regions, displaying a higher quality of life during urban expansion. Furthermore, the dominant aspect of low, medium, and high density ISA was captured with the north–south orientation, considering the sunlight conditions and traditional house construction customs in North China, Over 92.00% of the ISA was distributed in flat environment regions with a slope of less than 15°. When the water-resource service radius shifted from 0.5 km to 0.5–1 km and 1–2 km, high density vegetation displayed a dependence on water resources. Our results provide a new survey of the evolution of hierarchical urban land mapping during 1981–2021 and reveals the relationship with physical medium environments, providing an important reference for relevant research.

Impervious Surface Area Patterns and Their Response to Land Surface Temperature Mechanism in Urban–Rural Regions of Qingdao, China

“…Furthermore, the ISA comparison of our study city with a higher-level city (i.e., Beijing, one of the six highest-level cities, the capital city and political, economic, and external centre of China) was conducted in Northern China. The ISA ratio was 65.9% in 1981 and 73.9% in 2021 [46], showing an annual average increment rate of 0.2% from 1981 to 2021, which accounted for only half of the ISA growth rate in our research area. This may be due to the high ratio of ISA in Beijing in 1981 [46], which was higher than that of our study area (i.e., 65.9% in 1981 in Beijing vs. 63.3% in 2000 in Qingdao), and the further increment of ISA space was limited in Beijing, considering the impact of retaining a portion of residential green environment land within the built-up area [46,47].…”

“…The findings showed that the response values of the LST to the ISA in the urban regions were higher than those in the rural regions, both horizontally and vertically; the quantitative values were provided for this study. In the horizontal direction, the high-density ISA of cities meets the needs of commercial, residential, and public transportation [45,46] for many urban residents, and large areas of ISA often lead to higher temperature aggregation effects compared to rural areas, where the rural boundaries are relatively small and the ISA density is slightly lower [47]. In the vertical direction, the dense high-rise buildings in urban areas have a certain blocking effect on the horizontal air turbulence, causing temperatures to rise more vertically and forming a relatively high heat island effect [9,48].…”

“…The comparative study on the response changes in the LST to the ISA in urban and rural regions had many practical values. First, the comparison of the differences in the ISA structure between urban and rural areas helped in understanding the impacts of hardening urban and rural roads, home construction, and the density of community buildings [49] while also indirectly reflecting the greening situation in urban and rural regions, as demonstrated through community planning maps (i.e., the layout of the ISA and green spaces) [46,49]. Second, the differences in the energy aggregation between the urban and rural regions can be compared to provide a reference for relevant research in other regions, considering that the total amount of solar radiation that each region can receive is different.…”

Impact of Land Transition on Landscape and Ecosystem Service Value in Northeast Region of China from 2000–2020

“…In the previous literature, construction land [61], including urban, rural land, and industrial and mining land, is always treated as bare land, which often leads to the underestimation of the ecosystem service value in Northeast China. In the contexts of large-scale construction land expansion, ecological elastic cities, livable cities, and rural revitalization policies [64,65] have helped to increase the vegetation within the construction land area. Moreover, the impact of construction land on regional ecological functions such as purified environment, biodiversity, and aesthetic landscape, needs the ecosystem value assessment.…”