PROGRESS IN GEOGRAPHY ›› 2014, Vol. 33 ›› Issue (1): 42-49.doi: 10.11820/dlkxjz.2014.01.005

• Special Column: Annal Symposium on Geomorphology and Quaternary 2013 • Previous Articles     Next Articles

Morphological characteristics and developmental stages of loess tablelands based on DEM

TONG Chiming1,2, ZHOU Chenghu1, CHENG Weiming1, ZHANG Wenjie1,2, WANG Jiao1,2, LIU Haijiang3   

  1. 1. State Key Laboratory of Resource and Environmental Information System, Institute of Geographic Science and Natural Resources Research, CAS, Beijing 100101, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China;
    3. China National Environmental Monitoring Centre, Beijing 100012, China
  • Received:2013-10-01 Revised:2013-12-01 Online:2014-01-25 Published:2014-01-22

Abstract: DEM-based terrain analysis has been widely used in geomorphology. Currently most researches are qualitative or semi-quantitative, whereas quantitative analyses of large areas based on a variety of parameters are few and far between, and most studies use artificial field measurement with a small scale in the aspect of the relative age of the landscape entity. So, in this article, by using 30 m ASTER-GDEM, GIS and digital terrain analysis method, we extracted morphological parameters of a wide range of the areas of loess tablelands and determined their relative ages. We tried to provide basic knowledge of multi scale representation of the loess tablelands and fine landforms, achieved quantitative descriptions of the similarities and differences among the loess tablelands, and calibrated their developmental stages. First, we extracted positive landforms less than 15° in the Loess Plateau. Then, we acquired the top surface of the loess tableland using two parameters: gradient and waviness. We determined 1106 loess tablelands based on the subtraction between positive landform layer and the top surface layer. We selected 106 loess tablelands as samples to calculate average slope, axial ratio of top surface, gully density, top and bottom area ratio, percentage of negative terrain. The geometric mean of these five parameters was used as an index to estimate the relative age of the loess tableland. The index (abbreviated to I) was categorized into three levels: early development (I<1.74), middle development (1.74≤I<2.12) and late development (I≥2.12). The results showed that: (1) the morphological parameters of loess tablelands are different from one another in different developmental stages; (2) developmental stages are also inconsistent for the subtypes; (3) transitional type exhibits the characteristics more similar to the type of the previous stage. After calculating I of each subtype, we found that from early to late stages of the loess tablelands, I value increases gradually, which is consistent with other researchers' conclusions on the developmental stages of loess landforms.

Key words: DEM, Loess Plateau, loess tableland, morphological parameter, relative age

CLC Number: 

  • P931.6