Acta Geographica Sinica ›› 2021, Vol. 76 ›› Issue (7): 1747-1762.doi: 10.11821/dlxb202107013

• Land Use and Earth Surface Process • Previous Articles     Next Articles

Evolution characteristics of slope spectrum and slope-climbing effects of built-up land in China

ZHOU Liang1,2(), DANG Xuewei1,3, ZHOU Chenghu2, WANG Bo4, WEI Wei5   

  1. 1. Faculty of Geomatics, Lanzhou Jiaotong University, Lanzhou 730070, China
    2. State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
    3. National-Local Joint Engineering Research Center of Technologies and Applications for National Geographic State Monitoring, Lanzhou 730070, China
    4. School of Geography and Planning, Sun Yat-sen University, Guangzhou 510275, China
    5. College of Geography and Environment Sciences, Northwest Normal University, Lanzhou 730070, China
  • Received:2020-08-03 Revised:2021-04-27 Online:2021-07-25 Published:2021-09-25
  • Supported by:
    Science Foundation for the Excellent Youth Scholars of Ministry of Education of China(17YJCZH268);National Natural Science Foundation of China(41961027);Foundation of A Hundred Youth Talents Training Program of Lanzhou Jiaotong University

Abstract:

The changes in the scale and structure of built-up land is the basis for spatial development and planning of the national territory. Previous studies mainly focused on the characteristics and patterns of the horizontal expansion of built-up land, but little attention has been given to the "three-dimensional" gradient characteristics and effects of built-up land (such as slope-climbing). Therefore, based on Google Earth Engine, this study, for the first time as far as we know, uses DEM and land use data to draw built-up land slope spectrums and calculates the average built-up land climbing index (ABCI). The gradient characteristics and laws of the slope climbing of China's built-up land from 1990 to 2018 at the national, regional, provincial, and urban scales are systematically analyzed and the various spatial effects are explored. The results show that: (1) From 1990 to 2018, the area of built-up land with slope angle above 5° in China increased by 1.43 times, and the proportion of the total built-up land area rose from 10.25% to 14.81%. Particularly, the 2010-2015 period witnessed the fastest and largest slope-climbing development of built-up land in China. Moreover, the slope-climbing intensities in the central and western regions are higher than that in other regions. (2) According to the average built-up land climbing index (ABCI) and the upper limited slope angle change (ULSC), the 34 provinces (autonomous regions and municipalities) in China can be divided into three types: high-climbing, low-climbing, and horizontally expanding. Among them, the number of high-climbing provinces accounts for more than 50% of the total. And seven horizontally-expanding provinces present the distribution characteristics of "southeast-northwest" in space. (3) Before 2010, the cities with slope-climbing phenomenon were mainly mountainous cities. However, ethnic minority settlements and low-hill and gentle slope development pilot cities became the main force for the slope-climbing of built-up land after 2010. (4) The slope-climbing of built-up land can reduce the occupation of plain arable land and ecological land by built-up land expansion to a certain extent, and thus alleviate the contradiction between supply and demand of build-up land. However, it is worth noting that development and construction without reasonable plans and bulldozing mountains to build cities driven by real estate can also lead to increased geological disasters and ecological risks.

Key words: spatial planning, slope spectrum, three-dimensional city, urban expansion, GEE, China