关键词: 人口, 阈值, 动态分区, 空间化, 人居指数, 海岸带, 中国

Abstract:

Coastal zone is not only the hotspot of population aggregation and rapid economic growth, but also eco-environmentally sensitive, vulnerable to natural disasters. Detailed spatial distribution information of population is of great significance for solving resource allocation and disaster risk management in the coastal zone. This paper took the coastal cities in China as the study area. We combined the NPP - VIIRS data and NDVI data to construct Human Settlements Index (HSI), and selected the proportion of residential area per unit grid as a parameter to enhance the inter-demographic difference. Then, we used the dynamic partitioning samples and model to obtain the 1000 m grid population distribution data in the coastal zone of China (POP). To show the advantages of our proposed modeling approach, the published Chinese 1000 m grid population data (TPOP) and world population data with 100 m resolution (WorldPOP) were used to compare with our simulated POP data. For the comparison, three indicators were chosen: the macroscopic distribution characteristics, difference between urban and rural area, and population distribution within city. Results show that all the three data can reflect the macroscopic distribution characteristics of population in China's coastal zone, while POP has the best performance of depicting urban and rural differences in population distribution and the most detailed features of population distribution within city. According to the census and POP data, due to the influence of the coastal terrain and regional to national economic development strategies, the population distribution in China's coastal zone has obvious regional characteristics: (1) Topographically, the population density of montane and tidal flats areas is generally low (below 5 person/hm ²), while that of plain and estuary delta areas is generally high (over 10 person/hm ²). (2) At macroscopic scale, areas with high population density (over 25 person/hm ²) are mainly concentrated in coastal plain areas such as the Circum Bohai Sea region, the Yangtze River delta and the Pearl River delta; the population distribution in the north of the Yangtze River has the pattern of large dispersion and small concentration, especially in the provinces of Shandong and Jiangsu, the population distribution in the south of the Yangtze River is relatively concentrated, mainly in the coastal lowlands and plains in Zhejiang, Fujian, and Guangdong. (3) Regarding the urban and rural differences, the higher the urban level is, the more significant the gradient characteristics of population distribution will be; meanwhile, there is a huge difference in population density among urban, suburbs and exurban areas.

Key words: population, threshold, dynamic partitioning, spatialization, human settlements index, coastal zone, China