文章基本信息

标题：Seasonal Variation of Catenary-Bead Dunes in the Yangtze River Estuary: Causes and Implications
本地全文：下载
作者：Zheng, Shuwei ; Yuan, Xinmeng ; Yang, Suxian 等
期刊名称：Journal of Marine Science and Engineering
电子版ISSN：2077-1312
出版年度：2022
卷号：10
期号：7
页码：1-12
DOI：10.3390/jmse10070886
语种：English
出版社：MDPI AG
摘要：Low-angle lee-side slopes of dunes are commonly developed on the world’s riverbeds, and dune migration associated with sediment transport exert a major influence on riverine processes. However, the catenary-bead dune has been identified in the Yangtze River (YR) Estuary, featuring a higher lee-side angle. To date, the morphological variation and formation reasons of catenary-bead dunes in the YR Estuary remain uncharacterized. In this study, we used a multibeam echo system (MBES) to investigate the bedforms of the YR estuary during 2014–2015, as well as to discuss the seasonal variation of catenary-bead dunes. The results indicate that the catenary-bead dunes of the YR Estuary are characterized by growth during the flood season and extinction during the dry season. The lee-side angle is typically ~16.7°, which is larger than that of other dune types (3.7–8°) in the estuary; moreover, the catenary-bead dunes are higher than other dune types of the same length in the YR Estuary. The relationship between the dune height (H) and length (L) was found to be H = 0.1667L0.603 (R2 = 0.38), while the other dune types yielded the relationship of H = 0.0845L0.758 (R2 = 0.52). Strong runoff superimposing the ebb tide led to the development of catenary-bead dunes. Furthermore, the higher coarse sediment content (69.9–72%) and lower clay content (6.3–6.7%) of the riverbed sediment are favorable for their formation, while the higher curved crest-lines are favorable for the formation of the associated elliptical pits.
关键词：dunes; sedimentary environment; multibeam echo sounder; morphological variation; Yangtze River Estuary