Journal of Geographical Sciences ›› 2011, Vol. 21 ›› Issue (4): 689-704.doi: 10.1007/s11442-011-0873-2

• Applications of GIS • Previous Articles     Next Articles

The scaling method of specific catchment area from DEMs

YANG Xin, TANG Guoan, XIAO Chenchao, GAO Yiping, ZHU Shijie   

  1. 1. Key Laboratory of Virtual Geographic Environment, Nanjing Normal University, Ministry of Education, Nanjing 210046, China;
    2. Institute of Remote Sensing and Geographic Information System, Peking University, Beijing 100871, China
  • Received:2010-09-14 Revised:2011-02-20 Online:2011-08-15 Published:2011-08-05
  • Supported by:

    Key Project of National Natural Science Foundation of China, No.40930531; National Youth Science Foundation of China, No.40901185; Specialized Research Fund for the Doctoral Program of Higher Education, No.20093207120008

Abstract:

Specific Catchment Area (SCA) is defined as the upstream catchment area of a unit contour. As one of the key terrain parameters, it is widely used in the modeling of hydrology, soil erosion and ecological environment. However, SCA value changes significantly at different DEM resolutions, which inevitably affect terrain analysis results. SCA can be described as the ratio of Catchment Area (CA) and DEM grid length. In this paper, the scale effect of CA is firstly investigated. With Jiuyuangou Gully, a watershed about 70 km2 in northern Shaanxi Province of China, as the test area, it is found that the impacts of DEM scale on CA are different in spatial distribution. CA value in upslope location becomes bigger with the decrease of the DEM resolution. When the location is close to downstream areas the impact of DEM scale on CA is gradually weakening. The scale effect of CA can be concluded as a mathematic trend of exponential decline. Then, a downscaling model of SCA is put forward by introducing the scale factor and the location factor. The scaling model can realize the conversion of SCA value from a coarse DEM resolution to a finer one at pixel level. Experiment results show that the downscaled SCA was well revised, and consistent with SCA at the target resolution with respect to the statistical indexes, histogram and spatial distribution. With the advantages of no empirical parameters, the scaling model could be considered as a simple and objective model for SCA scaling in a rugged drainage area.

Key words: DEM, specific catchment area, scale effect, scaling model, Jiuyuan Gully