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- Title
An Algorithm‐Independent Definition of Effective Contour Length and Its Impacts on Pixel‐Scale Specific Catchment Area.
- Authors
Li, Zhenya; Lai, Xijun; Shi, Pengfei; Yang, Tao
- Abstract
Specific catchment area (SCA) is crucial terrain attribute extensively‐adopted in topographically‐driven modelings, which is function of total contributing area (TCA) and effective contour length (EL). Despite of numerous studies about SCA and TCA, none has focused on the investigation of existing EL definitions and adaption of point‐scale SCA concept to two‐dimensional pixel of digital elevation model (DEM). This work conducts a systematic research on rationality of existing EL definitions, proposal of new EL definition and concept of pixel‐scale SCA on gridded DEM. To overcome the defects of existing EL definitions, a new EL definition based on Triangular Discretization and Spatial Geometry (TDSG) is proposed in this work. SCA concept is extended from point scale to pixel scale for adapting to context of gridded DEM. The solutions of true pixel‐scale SCA, TCA, and EL in integral forms are deduced based on the solutions of point‐scale SCAs obtained by method of Zhou and Liu (2002, https://doi.org/10.1080/13658810210149425) or Gallant and Hutchinson (2011, https://doi.org/10.1029/2009WR008540). Besides, true pixel‐scale SCA, TCA, and EL are solved analytically for several synthetic surfaces. Numerical experiments indicate that (a) TDSG definition is superior to all existing EL definitions in physical mechanism, spatial characteristics, and computational precisions on synthetic surfaces and a real‐world DEM. (b) Spatial characteristics of SCA are controlled mainly by TCA and tuned slightly by EL, while overall precision of SCA is affected seriously by both TCA and EL. (c) TDSG definition is the only EL definition of responding accurately and sensitively to convergent and dispersive characteristics of local terrains. Key Points: An algorithm‐independent definition of effective contour length (EL) called Triangular Discretization and Spatial Geometry (TDSG) definition is proposed based on spatial geometry of local terrainsConcept of specific catchment area is extended from point scale to pixel scale for adapting to the context of gridded digital elevation modelTDSG definition shows superiorities to all existing EL definitions in both physical mechanisms and practical applications
- Subjects
DIGITAL elevation models; DEFINITIONS
- Publication
Water Resources Research, 2023, Vol 59, Issue 8, p1
- ISSN
0043-1397
- Publication type
Article
- DOI
10.1029/2022WR034036