| 摘要: |
| 了解海滩剖面变化可以更好地理解海滩动态过程。利用2007年5月～2014年12月近8 a青岛石老人海滩剖面的实测资料, 计算剖面各段单宽体积变化量及后滨宽度, 结合交叉小波和小波相干分析方法, 探讨海滩剖面中长期淤蚀变化特征及其控制因素。结果表明, 近8 a来海滩剖面表现为侵蚀状态,不同岸段侵蚀程度不同。剖面1岸段侵蚀明显, 剖面2 和剖面3岸段轻微侵蚀。剖面的变化过程可划分为平稳期、剧变期和微调期3个时期。各时期剖面的季节性变化较复杂, 平稳期具冬蚀夏淤的交替变化特征, 整体淤蚀量较小; 剧变期剖面呈阶段性蚀退, 变化幅度相对较大, 微调期剖面可能仍处于剧变期的恢复阶段, 季节性变化不明显。剧变期和微调期的小波交叉谱和相干谱分析显示, 波浪和前滨单宽体积相干性较好, 尤其当大于2m的波高达到10%以上, 海滩地形可以和波高变化产生同周期的变化。因此波高变化基本控制了剖面的季节变化。而海滩长周期变化主要受控于风暴潮作用及其漫长的恢复期, 沿岸输沙和海平面变化则一定程度上导致了剖面长期侵蚀格局的形成。 |
| 关键词: 岬湾海滩 中长期变化 控制因素 交叉谱和相干谱分析 青岛石老人海滩 |
| DOI：10.11759/hykx20160317001 |
| 分类号: |
| 基金项目:国家自然科学基金项目( 41176039, 41376054 和41410304022);国家海洋局公益性项目(201405037) |
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| Characteristics of long- and medium-term variation in bay beach profiles and associated control factors at Shilaoren Beach, Qingdao |
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FENG Zhe,WANG Yong-hong,YILI Da-ling
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| Abstract: |
| Analysis of long-and medium-term variation characteristics of profiles is important in understanding dynamic beach processes. Based on nearly eight years of measured profiles data in the Shilaoren arc-shaped bay beach (Qingdao) from May 2007 to December 2014, the backshore width and beach volume data of the unit width were obtained. Use of the cross wavelet method and wavelet coherence analysis enabled analysis of long-and medium-term changes in trend and dynamic factors. Results show differences in the long-term variation of every beach profile, where Profile 1 eroded significantly but Profiles 2 and 3 suffered only slight erosion overall. In addition, the most recent eight years were divided into three stages: a stable period of 5 years (2007～2011), a 1-year change period (2012), and a fine-tuning phase of 2 years (2013～2014). Complex changes was observed in the medium-term beach profiles throughout the three stages. Seasonal changes in the profile during the stable period were characterized by erosion during winter and acceleration in summer but with little erosion or deposition overall. However, the change period mainly showed that the profile was eroded back in stages with a relatively substantial total volume of scouring-silting. Results of cross wavelet spectrum analysis of the backshore volume of unit width and the wave height during the change period showed a good correlation, particularly when more than 10% of all waves had a wave height of over 2 m as this had a definite effect on beach topography. Seasonal variations in the profile during the fine-tuning period were not obvious, and this may be related to the recovery stage phase of the profile. It can thus be confirmed that seasonal waves are the main driving force of changes in the beach profile in the medium term. Although human intervention may lead to erosion-deposition on parts of the beach, this is not the controlling factor. In addition, long-term changes in the profile are mainly effected by storm waves and the associated long recovery time; thus, to some extent, long-shore sediment transport and sea level changes are forming a long-term erosion pattern. |
| Key words: bay beach long and medium-term changes control factors wavelet cross and coherence analysis Shilaoren Beach in Qingdao |
