Anisotropy characteristics of exposed gravel beds revealed in high-point-density airborne laser scanning data

Huang, Guo-Hao and Wang, Chi-Kuei and Wu, Fu-Chun and Atkinson, Peter Michael (2016) Anisotropy characteristics of exposed gravel beds revealed in high-point-density airborne laser scanning data. IEEE Geoscience and Remote Sensing Letters, 13 (8). pp. 1044-1048. ISSN 1545-598X

[img]
Preview
PDF (LGRS2562061)
LGRS2562061.pdf - Accepted Version
Available under License Creative Commons Attribution-NonCommercial.

Download (4MB)

Abstract

The aim of this study was to examine the relationship between the anisotropy direction of exposed gravel bed and flow direction. Previous studies have shown that the anisotropy direction of a gravel bed surface can be visually determined in the elliptical contours of 2-D variogram surface (2DVS). In this letter, airborne laser scanning (ALS) point clouds were acquired at a gravel bed, and the whole data set was divided into a series of 6 m × 6 m subsets. To estimate the direction of anisotropy, we proposed an ellipse-fitting-based automatic procedure with consideration given to the grain size characteristic d50 to estimate the primary axis of anisotropy [hereafter referred to as the primary continuity direction (PCD)] in the 2DVS. The ALS-derived PCDs were compared to the flow directions (for both high and low flow) derived from hydrodynamic model simulation. Comparison of ALS-derived PCDs and simulated flow directions suggested that ALS-derived PCDs could be used to infer flow direction at different flow rates. Furthermore, we found that the ALS-derived PCDs estimated from any elliptical contour of the 2DVS exhibited a similar orientation when the contours of the 2DVS reveal the clear anisotropic structure, demonstrating the robustness of the technique.

Item Type:
Journal Article
Journal or Publication Title:
IEEE Geoscience and Remote Sensing Letters
Additional Information:
©2016 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2200/2208
Subjects:
ID Code:
83517
Deposited By:
Deposited On:
12 Apr 2017 11:02
Refereed?:
Yes
Published?:
Published
Last Modified:
25 Oct 2020 04:32