全球城市扩展与土地覆盖变化

进入21世纪以来,全球城市快速发展。据联合国报告,2018年有42.2亿的人口居住在城市,占全球总人口的55％,预计2050年全球城市化率将达到68%。城市扩展和土地覆盖变化是权衡城市人居环境质量、生态系统服务乃至人类福祉的重要内容。全球范围内城市下垫面高精度遥感监测,可为实现联合国2030年可持续发展目标“建设包容、安全、有抵御灾害能力和可持续的城市和社区”提供科学认知和决策依据。 采用卫星遥感技术监测了近二十年全球城市扩展和土地覆盖变化,辅以社会经济统计等资料,分析了全球9个超大城市群和1468个典型城市扩展的时空格局和分异规律,揭示了不同区域的城市土地覆盖分布特征及其变化态势,评价了不同土地资源禀赋和收入水平国家城市绿地空间的配置差异,为全球城市未来可持续发展提出了建议。 在时间尺度上拓展到了21世纪第二个十年,在监测内容上增加了城市土地覆盖（指城市不透水面、绿地空间和水域等覆盖类型）的信息,形成了近二十年全球城市扩展与土地覆盖变化遥感制图产品。 监测结果表明,全球城市土地面积由2000年的23.90万km2增加到2020年的51.98万km2,扩展了28.08万km2。全球城市不透水面快速增长,从2000年的15.30万km2增长到2020年的31.19万km2。全球城市绿地空间面积显著增加,从2000年的6.54万km2增加到2020年的17.16万km2,占城市土地面积比例由27.36%增加到33.01%。 编制的数据主要来源于Landsat、HJ、ZY、GF、DMSP/OLS、NPP/VIIRS、社会经济统计数据和城市规划资料等,应用大数据、机器学习和人工交互解译等方法,生成了2000年、2010年和2020年三期全球城市扩展和土地覆盖系列数据产品。

Since the turn of the 21st century, global urbanization has advanced at a rapid pace. According to a United Nations report, 4.22 billion people resided in urban areas in 2018, accounting for 55% of the global total population; the global urbanization rate is projected to reach 68% by 2050. Urban expansion and land cover change are critical factors in balancing the quality of urban human settlements, ecosystem services, and even human well-being. High-precision remote sensing monitoring of urban underlying surfaces worldwide can provide scientific insights and decision-making support for achieving the UN 2030 Sustainable Development Goal of "building inclusive, safe, disaster-resilient and sustainable cities and communities".

This study employed satellite remote sensing technology to monitor global urban expansion and land cover changes over the past two decades, supplemented by socio-economic statistical data and other relevant materials. It analyzed the spatiotemporal patterns and differentiation rules of urban expansion in 9 mega-city agglomerations and 1468 typical cities worldwide, revealed the distribution characteristics and changing trends of urban land cover across different regions, evaluated the disparities in the allocation of urban green spaces among countries with varying land resource endowments and income levels, and put forward recommendations for the future sustainable development of global cities.

The temporal scope was extended to the 2010s (the second decade of the 21st century), and monitoring content was expanded to include information on urban land cover (referring to coverage types such as urban impervious surfaces, green spaces, and water bodies), resulting in a remote sensing mapping product of global urban expansion and land cover changes over the past two decades.

The monitoring results show that the global urban land area increased from 239,000 km² in 2000 to 519,800 km² in 2020, with an expansion of 280,800 km². The global urban impervious surface area grew rapidly, rising from 153,000 km² in 2000 to 311,900 km² in 2020. The global urban green space area increased significantly, from 65,400 km² in 2000 to 171,600 km² in 2020, and its proportion of the total urban land area rose from 27.36% to 33.01%.

The compiled data mainly come from Landsat, HJ, ZY, GF, DMSP/OLS, NPP/VIIRS, socio-economic statistical data, urban planning materials, and other sources. Using methods such as big data, machine learning, and manual interactive interpretation, a series of global urban expansion and land cover data products for the years 2000, 2010, and 2020 were generated.

搜集汇总

背景与挑战

背景概述

该数据集提供了2000年至2020年全球城市扩展与土地覆盖变化的遥感监测产品，覆盖全球范围，空间分辨率为30米。它利用多源遥感数据（如Landsat、HJ等）和社会经济统计信息，通过大数据和机器学习方法，生成了三个时间点（2000、2010、2020年）的数据，重点分析了城市土地面积、不透水表面和绿地空间的变化趋势，例如全球城市土地面积在20年间从239,000 km²扩张到519,800 km²。数据集旨在支持联合国可持续发展目标，为城市可持续规划提供科学依据。