What the spatial pattern of global urban surface area that human depends on is the important issue, which is widely concerned at present. Research have established regression models that estimated the fraction of ISA/UGS in global 30 cities for validation using MODIS NDVI and DMSP/OLS nighttime light imageries. Global impervious surface area and green space (ISA/UGS) was mapped. Furthermore, the fraction of ISA/UGS within built-up area was estimated.
The research revealed the global ISA of 45.26×104 km2, accounting for 60.01% of the global urban land area. North America, Europe, and Asia accounted for 84.25% of the world's total ISA. The research also found that the proportion of ISA situated in built-up areas on the continental scale followed the order of Africa (>70%)>South America>Oceania>Asia (>60%)>North America>Europe (>50%), and these areas were mostly in southeastern North America, southwestern Europe, and eastern and western Asia. North America, Europe, and Asia accounted for 89.44% of the world's total UGS. The cities of developed countries in Europe and North America exposed a dramatic mosaic of ISA and UGS composites in urban construction. Therefore, the proportion of UGS is relatively high in those cities. However, in developing and underdeveloped countries, the proportion of UGS in built-up areas is relatively low, and urban environments need to be improved for livability.
The mapping of global ISA/UGS is important for improving the quality of human settlements, guiding urban and regional development planning, and promoting the urban environmental quality toward ecological, livable, and sustainable goals.
This work was supported by the Major Projects of the National Natural Science Foundation of China (Grant No. 41590842), the Strategic Priority Research Program of the Chinese Academy of Sciences, Pan-Third Pole Environment Study for a Green Silk Road (Pan-TPE) (Grant No. XDA20040400) and the National High Technology Research and Development Program of China (Grant No. 2013AA122802).
See the article: Kuang, W. (2019). Mapping global impervious surface area and green space within urban environments. Science China Earth Sciences. doi:10.1007/s11430-018-9342-3
This article was published online.