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Arid Land Geography ›› 2025, Vol. 48 ›› Issue (9): 1600-1611.doi: 10.12118/j.issn.1000-6060.2024.565

• Earth Surface Process • Previous Articles     Next Articles

Morphological calculation of Caragana tibetica nebkhas based on UAV laser radar technology in Gonghe Basin, Qinghai Province

SHANG Yili(), LI Yue, XIAO Fengjun(), NAN Weige, ZHANG Zhi, WANG Lijie   

  1. School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, Shaanxi, China
  • Received:2024-09-22 Revised:2025-02-08 Online:2025-09-25 Published:2025-09-17
  • Contact: XIAO Fengjun E-mail:syl@snnu.edu.cn;xiaofengjun@snnu.edu.cn

Abstract:

To explore the applicabilities of various estimation formulas for the morphological parameters of reported nebkhas and justify their selections, the morphological parameters, such as the bottom area and volume, of 300 Caragana tibetica nebkhas on the west of Longyangxia Reservoir (Gonghe Basin, Qinghai Province, China) were measured using the laser radar technology of an unmanned aerial vehicle (UAV). The results are summarized in four points. (1) UAV laser radars can accurately determine the morphologies of C. tibetica nebkhas, obtaining average relative errors of 0.70%, 1.13%, and -1.67% for the length axis (L), width axis (W), and height (H), respectively, with corresponding root-mean-square errors (RMSEs) of 0.02 m, 0.03 m, and 0.03 m, respectively. Additionally, the RMSEs of the plane and three-dimensional (3D) accuracy of the 3D model were 0.03 m and 0.04 m, respectively, satisfying accuracy requirements. (2) The L, W, and H of the C. tibetica nebkhas remained largely unchanged, and their variation coefficients were between 0.26 and 0.33. Additionally, these parameters exhibited a significant correlation (P<0.01), indicating that the morphologies of the nebkhas were determined by coordinated L, W, and H increases. Additionally, the crust, dead shrubs, and wind erosion pits on the surface of the nebkhas indicate that the nebkhas had evolved from the mature stage to the decline stage. (3) The following formulas were used to determine the bottom area of the C. tibetica nebkhas: π[(L+W)/4]2, πLW/4, and LW/2, obtaining total relative errors of -0.79%, -1.26%, and -37.14%, respectively. Among them, π[(L+W)/4]2 and πLW/4 were considered suitable for the study area. Further, the following formulas were used to determine their volume: 3πLWH/32, πLWH/12, LWH/6, πH{[3(L+W)/4]2+H2}/6, and πLWH/6, with total relative errors of -6.15%, -16.58%, -46.89%, 59.14%, and 66.83%, respectively. The modified formula, πLWH/10, yielded a total relative error of 0.10%, as well as a low dispersion degree, making it the most suitable formula for the study area. In summary, the estimation of the bottom areas and volumes of nebkhas requires the careful consideration of the influence of the vegetation type, development stage, habitat, or sand-source richness, as this would ensure the selection of appropriate estimation methods based on local conditions.

Key words: nebkhas, drone laser point cloud, geometric formula, total relative error