基于无人机航测的粤西海滩滩角形态特征提取与短期演变研究

Extraction of beach cusp morphological characteristics and short-term evolution based on UAV aerial survey in Western Guangdong beaches

  • 摘要: 滩角是位于海滩的典型韵律地貌,其形成与演变机制是海岸动力地貌研究的重要课题.本研究以粤西东海岛中部海滩为典型研究区,基于无人机航测技术获取短期对比影像数据,利用可见光影像生成高精度数字地表模型,通过等值线法提取滩角间距、深度、高度等形态参数,并运用皮尔逊相关性分析方法,系统分析了监测期内滩角形态的短期演变特征.结果表明:1)在监测期间,滩角形态呈现显著均一化趋势,数量增加,分布趋于规整,间距保持稳定,但深度和高度均值降低,参数离散度普遍下降;2)在稳定中风浪(波高0.6~0.9 m,E和ENE向)作用下,形态参数间相关性显著衰减,间距-高度完全解耦,揭示了滩角系统在短期监测内处于自组织过程中由正反馈占主导地位的形态构建与调整期;3)实测值与边缘波理论预测值存在显著偏差,表明在本研究监测的动力条件与时间尺度下,边缘波理论对研究区滩角形成的解释能力有限.本研究揭示了无人机航测技术在海滩滩角形态特征提取及监测中的适用性与可靠性,为理解海岸地貌短期演变过程提供了高分辨率实证案例.

     

    Abstract: Beach cusps are typical rhythmic landforms, their formation and evolution mechanisms are important in coastal dynamic geomorphology. In this work the central beach of Donghai Island in Western Guangdong was studied. UAV aerial survey technology was used to obtain short-term comparative image data, high-precision digital surface models were generated using visible-light imagery. Morphological parameters (beach cusp spacing, depth and height) were extracted using the contour method, Pearson correlation analysis was used to analyze short-term evolution characteristics. Beach cusp morphology was found to show a significant trend toward homogenization in the monitoring period. The number of cusps increased (from 25 to 48), their spatial distribution became more regular, spacing remained stable, while the mean depth and height decreased, with an overall reduction in the dispersion of parameters. Under the influence of stable moderate swells (wave height 0.6–0.9 m, E and ENE directions), the correlations among morphological parameters decreased significantly, and the spacing-height relationship became completely decoupled. This indicates that the beach cusp system was in a phase of morphological construction and adjustment dominated by positive feedback within the self-organization process. Significant deviations were observed between measured values and predicted values of edge wave theory, suggesting that explanatory power of edge wave theory is limited under hydrodynamic conditions and timescale of this monitoring period. This study demonstrates applicability and reliability of UAV aerial survey technology for extracting and monitoring morphological characteristics of beach cusps; this provides a high-resolution empirical case for understanding short-term evolution processes of coastal landforms.

     

/

返回文章
返回