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海平面上升的海岸形态响应研究方法与进展 被引量:19
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作者 李恒鹏 杨桂山 《地球科学进展》 CAS CSCD 2000年第5期598-603,共6页
海岸带是人口最稠密的地带 ,全世界几乎一半的人口生活在沿海地区 [1] (根据 UNCEDDE的定义 ,以距海岸线 1 50 km计 )。受全球变化 ,尤其是 2 1世纪海平面加速上升的影响 ,海岸将发生复杂的形态响应过程 ,包括海岸侵蚀、滩地淹没和湿地... 海岸带是人口最稠密的地带 ,全世界几乎一半的人口生活在沿海地区 [1] (根据 UNCEDDE的定义 ,以距海岸线 1 50 km计 )。受全球变化 ,尤其是 2 1世纪海平面加速上升的影响 ,海岸将发生复杂的形态响应过程 ,包括海岸侵蚀、滩地淹没和湿地沉积平衡的调整等 ,从而危害人类的生存和发展 ,引起世界沿海各国政府和科学界的广泛关注。从海平面上升海岸响应历史记录研究、海岸均衡剖面研究和形态响应模拟研究三个方面概述了海平面上升海岸形态响应的国内外研究进展 ,并对各种研究方法的适用范围、优点及局限性进行了讨论。 展开更多
关键词 海平面上升 海岸形态响应 均衡剖面 数值模拟
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基于线性材料力学模型的海岸岬湾形态特征研究
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作者 吕小龙 郑建国 +1 位作者 许国辉 宋玉鹏 《海洋通报》 CAS CSCD 北大核心 2023年第4期385-397,共13页
具有岬湾形态的海岸一般具有良好的稳定性,是海岸侵蚀修复中经常使用的岸线形态,而岬湾形态特征与海岸水动力之间的确切关系还没有形成量化的描述。本研究定义了海岸岬湾形态特征的基本参数,基于历史卫星影像的解译,采用比拟、统计的研... 具有岬湾形态的海岸一般具有良好的稳定性,是海岸侵蚀修复中经常使用的岸线形态,而岬湾形态特征与海岸水动力之间的确切关系还没有形成量化的描述。本研究定义了海岸岬湾形态特征的基本参数,基于历史卫星影像的解译,采用比拟、统计的研究方法,统计了全球240个岬湾的平面形态特征参数,分析得出:(1)岬控比(K)的值介于1.2至1.8之间,平均值为1.41,方差为0.02,标准差为0.16;(2)凸出度(ρ)的值介于0.2至0.51之间,平均值为0.34,方差为0.01,标准差为0.08;(3)根据弧形岸线形态和波浪绕射的不同,将自然海岸岬湾形态分为切线夹曲线型、曲线连切线型和曲线夹切线型3类。采用数值模拟,将线性材料受力变形的过程比拟于岬湾海岸线受水动力作用达到静态平衡过程,以线性材料为媒介,初步探究了岬湾平面形态与波浪之间的关系,对海岸线的预测、修复和保护海岸具有一定参考价值。 展开更多
关键词 海岸岬湾形态 波浪 比拟法 线性材料 海岸线预测
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海岸线形态探讨
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作者 陈翠翠 蒋大煌 张怀慧 《港工技术》 2020年第4期1-6,共6页
从海岸原始形态入手,以波浪作用为主要动力,泥沙运动为媒体,介绍了沙质海岸形态中的稳定型和动态平衡型海岸的形态及其形成过程。其中以自然界广泛存在的耳朵型海岸为对象,分析了形成过程,特别强调了地球自转柯氏力在形成过程中的作用,... 从海岸原始形态入手,以波浪作用为主要动力,泥沙运动为媒体,介绍了沙质海岸形态中的稳定型和动态平衡型海岸的形态及其形成过程。其中以自然界广泛存在的耳朵型海岸为对象,分析了形成过程,特别强调了地球自转柯氏力在形成过程中的作用,这在以往有关海水运动的文献中是被忽视的因素。在动态平衡型海岸线的分析中,指出所谓平衡是指岸线形态不变,但岸线可能有前移或后退的可能。全文内容可为海岸工程选址及人工海岸形态提供参考。 展开更多
关键词 海岸形态 稳定型 动态平衡型 泥沙运动 人工岸线
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适应中国海岸空间形态的海籍影像数据块编码研究
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作者 管梅芳 蒋雪中 恽才兴 《海洋学报》 CAS CSCD 北大核心 2012年第1期95-100,共6页
我国海岸空间形态以台湾海峡为界,北部呈南北狭长型,南部呈东西狭长型,拟建海籍影像数据库需要适应这种特殊形态。为此,构建了二、四叉树混合分块模型,并针对该模型提出了改进的CMorton编码,利用长江口和杭州湾多分辨率卫星遥感数据构... 我国海岸空间形态以台湾海峡为界,北部呈南北狭长型,南部呈东西狭长型,拟建海籍影像数据库需要适应这种特殊形态。为此,构建了二、四叉树混合分块模型,并针对该模型提出了改进的CMorton编码,利用长江口和杭州湾多分辨率卫星遥感数据构建了一个模拟环境对该编码进行测试。结果表明:与常用的行列号编码方式相比,改进的编码能够明显地缩短数据块的构建时间,能够满足海籍数据实时可视化的要求,有效地适应中国海籍影像对应的空间形态。 展开更多
关键词 CMorton编码 海籍 海岸空间形态 影像数据库
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第28届国际海岸工程会议
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作者 陶建华 《国际学术动态》 2003年第3期48-48,共1页
第28届国际海岸工程会议于2002年7月7日至12日在英国威尔士首府Cardiff市政厅召开,来自50多个国家500多位学者、工程师参加了大会。国际海岸工程会议是一个很有权威性的国际会议,有关海岸工程一些新理论、新方法和新结构常常在这个会议... 第28届国际海岸工程会议于2002年7月7日至12日在英国威尔士首府Cardiff市政厅召开,来自50多个国家500多位学者、工程师参加了大会。国际海岸工程会议是一个很有权威性的国际会议,有关海岸工程一些新理论、新方法和新结构常常在这个会议上首先提出。国际上一些从事海岸工程研究的学者、工程界人士都经常参加这一会议。我国历届参加会议的人较少。 展开更多
关键词 国际海岸工程会议 泥沙运输 波浪 海岸形态 数值模拟
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泥沙粒径组成的不均匀性对海岸地形演变的影响
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作者 徐杰 邹志利 《海洋通报》 CAS CSCD 北大核心 2018年第4期440-449,共10页
海岸的泥沙输沙模式决定着海岸地形的演变特征,不同的输沙模式会导致形成横向和倾斜沙坝、裂流沟槽等不同的地貌特征。本研究提出了一种考虑泥沙分布不均匀性的新输沙率公式,该公式包含了反映泥沙粒径不均匀性的概率加权和考虑泥沙颗粒... 海岸的泥沙输沙模式决定着海岸地形的演变特征,不同的输沙模式会导致形成横向和倾斜沙坝、裂流沟槽等不同的地貌特征。本研究提出了一种考虑泥沙分布不均匀性的新输沙率公式,该公式包含了反映泥沙粒径不均匀性的概率加权和考虑泥沙颗粒遮蔽效应的加权。该公式所给出的载沙量与传统输沙率公式的对比表明,相同中值粒径下,二者有明显差异。将该输沙率公式应用于地形线性不稳定分析,所得到的地形不稳定性增长率不同于假定泥沙为均匀的结果,对应的地形变形波长也有所差别。 展开更多
关键词 地形线性不稳定分析 泥沙粒径 输沙率 海岸形态
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海岸底床剖面演变模拟与分析
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作者 蔡淑娟 《水利科技与经济》 2014年第10期36-39,共4页
近岸水下沙坝的位置与高度是河口海岸底床变化的主要原因,波浪与地形之间的耦合与反馈造成了沙坝向海连续迁移。使用LITPACK的添加模块LITPROF模拟沙质海岸剖面形态变化主要是沙坝的形成与迁移,通过模拟不同波浪入射角及剖面坡度对沙坝... 近岸水下沙坝的位置与高度是河口海岸底床变化的主要原因,波浪与地形之间的耦合与反馈造成了沙坝向海连续迁移。使用LITPACK的添加模块LITPROF模拟沙质海岸剖面形态变化主要是沙坝的形成与迁移,通过模拟不同波浪入射角及剖面坡度对沙坝形成与迁移的影响,得出沙坝主要在波浪破碎点处形成,波浪入射角增大,沙坝离岸迁移越快;底床坡度越陡,沙坝产生与迁移越快,岸滩变形也越大。 展开更多
关键词 海岸底床形态 沙坝 波浪入射角 底床坡度
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直线基线规则的演进、适用及其限制:判例、立法与学说
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作者 马得懿 夏雨 《中国海洋大学学报(社会科学版)》 2022年第2期1-13,共13页
在海洋划界实践中,直线基线规则的适用具有由无序向统一演进的基本特征。从历史脉络上看,直线基线规则主要经历了海岸线初略作为基线、低潮线被视为基线、直线基线规则初步确立以及直线基线规则为国际立法所固化等历史阶段。对直线基线... 在海洋划界实践中,直线基线规则的适用具有由无序向统一演进的基本特征。从历史脉络上看,直线基线规则主要经历了海岸线初略作为基线、低潮线被视为基线、直线基线规则初步确立以及直线基线规则为国际立法所固化等历史阶段。对直线基线规则的理解,应该建立在直线基线历史发展、海岸形态以及确定基线科学手段形成的基础上。不仅如此,直线基线规则的判例、国际立法以及学说,为阐释直线基线规则的演进、适用及其限制提供了正当性路径。解释直线基线规则的适用条件及其限制,应该充分顾及到海洋划界的复杂性。这不但是不断完善直线基线规则的需要,而且是实现1982年《联合国海洋法公约》第七条立法意旨与目的的理性方略。 展开更多
关键词 直线基线 英、挪渔业案 海岸形态 岛屿分布 体系化
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华南岬间弧形海岸平面形态影响因素及类型 被引量:10
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作者 李志强 李维泉 +1 位作者 陈子燊 朱雅敏 《地理学报》 EI CSCD 北大核心 2014年第5期595-606,共12页
对华南47个典型弧形海岸,选取表征海岸平面形态特征、海岸水动力等10个地貌动力要素,利用主成分、分层聚类和非度量多维尺度分析等方法对影响华南弧形海岸的主要因素及海岸类型进行研究,结果表明:(1)华南弧形海岸平面形态主要受到地质... 对华南47个典型弧形海岸,选取表征海岸平面形态特征、海岸水动力等10个地貌动力要素,利用主成分、分层聚类和非度量多维尺度分析等方法对影响华南弧形海岸的主要因素及海岸类型进行研究,结果表明:(1)华南弧形海岸平面形态主要受到地质构造、水动力、海陆供沙等要素共同作用;(2)华南弧形海岸可以分成4个大类。第一类型是中、强潮型海岸;第二类型主要为强浪型海岸;第三类型是地质构造控制的大型弧形海岸;第四类型只有洋浦湾与铺前湾,是比较独特的弧形海岸类型;(3)利用非度量多维尺度分析探究地貌动力要素及海岸形态与类型的关系,说明华南弧形海岸聚类分析结果具有一定的客观性。 展开更多
关键词 海岸平面形态 弧形海岸 主成分分析 聚类分析 非度量多维尺度分析
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Progress in Studies on the Equilibrium Shape of Headland-bay Shoreline
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作者 李志龙 陈子燊 《Marine Science Bulletin》 CAS 2007年第1期74-83,共10页
Research on the laws controlling the shoreline equilibrium shape has been one important topic of studying the evolvement and stabilization of sandy coasts. After a brief review of the progress on the equilibrium shape... Research on the laws controlling the shoreline equilibrium shape has been one important topic of studying the evolvement and stabilization of sandy coasts. After a brief review of the progress on the equilibrium shape laws research, five models are introduced in detail. Advantages and disadvantages of these models are then discussed, which leads to the conclusion that the empirical formula integrating with analysis of mechanism should be the future direction of study on the headland-bay equilibrium shape laws. Finally, the importance of the study on the equilibrium shape of headland-bay in China is also discussed. 展开更多
关键词 HEADLAND-BAY equilibrium shape model shoreline evolution
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Beach Morphology and Coastline Evolution in the Southern Bohai Strait 被引量:3
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作者 ZHANG Wei WU Jianzheng +5 位作者 LI Weiran ZHU Longhai HU Rijun JIANG shenghui SUN Yonggen WANG Huijuan 《Journal of Ocean University of China》 SCIE CAS 2015年第5期803-815,共13页
The beach studied in this paper spans a length of 51 km and is one of several long sandy beaches in the southern Bohai Strait. Due to the obstruction of islands in the northeast and the influence of the underwater top... The beach studied in this paper spans a length of 51 km and is one of several long sandy beaches in the southern Bohai Strait. Due to the obstruction of islands in the northeast and the influence of the underwater topography, the wave environment in the offshore area is complex; beach types and sediment transport characteristics vary along different coasts. The coastlines extracted from six aerial photographs in different years were compared to demonstrate the evolving features. Seven typical beach profiles were selected to study the lateral beach variation characteristics. Continuous wind and wave observation data from Beihuangcheng ocean station during 2009 were employed for the hindcast of the local wave environment using a regional spectral wave model. Then the results of the wave hindcast were incorporated into the LITDRIFT model to compute the sediment transport rates and directions along the coasts and analyze the longshore sand movement. The results show that the coastline evolution of sand beaches in the southern Bohai Strait has spatial and temporal variations and the coast can be divided into four typical regions. Region (1), the north coast of Qimudao, is a slightly eroded and dissipative beach with a large sediment transport rate; Region (II), the southwest coast of Gangluan Port, is a slightly deposited and dissipative beach with moderate sediment transport rate; Region (III), in the central area, is a beach that is gradually transformed from a slightly eroded dissipative beach to a moderately or slightly strong eroded bar-trough beach from west to east with a relatively moderate sediment transport rate. Region (IV), on the east coast, is a strongly eroded and reflective beach with a weak sediment transport rate. The wave conditions exhibit an increasing trend from west to east in the off- shore area. The distribution of the wave-induced current inside the wave breaking region and the littoral sediment transport in the nearshore region exhibit a gradual weakening tendency from west to east, which is opposite to the trend of the wave conditions out- side the breaking region. The presence of submerged shoal (Dengzhou Shoal), deep trough (Dengzhou Channel), islands and irregu- lar topography influnces the wave climate, beach types, wave-induced current features, littoral sediment transport trends and coast- line evolution patterns in the southern Bohai Strait. Human activities, such as the sand exploitation of Dengzhou Shoal and other coastal engineering projects, also influence the beach morphology and coastline evolution. 展开更多
关键词 sand beach coastline evolution profile feature wave hind-casting wave-induced current littoral sediment transport
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First record of Biecheleria cincta (Dinophyceae) from Chinese coasts, with morphological and molecular characterization of the strains 被引量:4
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作者 罗肇河 杨维东 +1 位作者 徐斌 顾海峰 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2013年第4期835-845,共11页
The presence ofBiecheleria cincta (=Woloszynskia cincta) in the Chinese coasts is reported for the first time. In scanning electron microscope, three to five series of vesicles and an elongated apical vesicle (EAV... The presence ofBiecheleria cincta (=Woloszynskia cincta) in the Chinese coasts is reported for the first time. In scanning electron microscope, three to five series of vesicles and an elongated apical vesicle (EAV) were visible in the epicone, and both the hypocone and the cingulum had three series of vesicles each. Thin sections revealed that B. cincta possesses stalked pyrenoids and an unusual eyespot consisting of a stack of cistemae with brick-like materials (type E), thus supporting its transfer from Woloszynskia to Biecheleria. Spiny cysts formed spontaneously in culture, with an encystment rate of around 20%. Both large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer region (ITS) sequences in 12 strains from the Chinese coasts were determined. Phylogenetic analyses based on LSU rDNA and ITS sequences using Bayesian inference and maximum likelihood revealed two distinct ribotypes (referred to as ribotype A and B) in B. cincta. ITS region pairwise distances within B. eincta ranged from 0.024 to 0.072, suggesting the existence of a complex of cryptic species. 展开更多
关键词 Biecheleria CYST internal transcribed spacer region (ITS) type E eyespot ULTRASTRUCTURE Woloszynskia cincta
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Morphological Studies on the Infraciliature of a Planktonic Ciliate,Tintinnopsis brasiliensis(Ciliophora:Tintinina) 被引量:1
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作者 CAI Shengfang SONG Weibo +1 位作者 XU Dapeng CHIANG Kuoping 《Journal of Ocean University of China》 SCIE CAS 2006年第1期55-57,共3页
A poorly-described marine planktonic ciliate, Tintinnopsis brasiliensis Kofoid & Campbell, 1929, collected from the Taiping Cape of Qingdao, China, was morphologically investigated based on permanent preparation afte... A poorly-described marine planktonic ciliate, Tintinnopsis brasiliensis Kofoid & Campbell, 1929, collected from the Taiping Cape of Qingdao, China, was morphologically investigated based on permanent preparation after protargol impregnation and was compared with other related congeners. According to the infraciliature, three ciliary groups can be recognized, which reveals a very stable structure among specimens and denotes that the pattern of infraciliature is, apart from the features of the lorica, a highly reliable criterion for species identification. 展开更多
关键词 INFRACILIATURE Tintinnina CILIOPHORA Tintinnopsis brasiliensis
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Morphological study of the genus Herposiphonia (Rhodophyta, Rhodomelaceae) on the coast of eastern Guangdong, China, with a description of H. pinnata sp. nov. 被引量:2
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作者 丁兰平 谭华强 +2 位作者 张全亮 曾令昭 黄冰心 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第2期271-282,共12页
We present a taxonomic study of taxa of the red algae genus Herposiphonia (Rhodophyta, Rhodomelaceae), collected from the coast of eastern Guangdong, China. We made detailed morphological studies and considered rece... We present a taxonomic study of taxa of the red algae genus Herposiphonia (Rhodophyta, Rhodomelaceae), collected from the coast of eastern Guangdong, China. We made detailed morphological studies and considered recent taxonomic criteria for species delimitation, and are making the first report of five different species on the coast of Guangdong, including a new species. The species identified were H. caespitosa Tseng, H. hollenbergii Dawson, H. pecten-veneris (Harvey) Falkenberg, H. subdisticha Okamura and H. pinnata Ding and Tan sp. nov. H. pinnata sp. nov. is characterized by bright green thaUi; most parts of the feathery thalli are free of the substratum; determinate branches and indeterminate branches are arranged in a chaotic sequence; the primary axis has bare segments; the determinate branch has 9-11 periaxial cells per segment; vegetative trichoblasts are abundant; and tetrasporangia are formed on the middle of the determinate branch with 1-8 successive segments in a single rectilinear series. This paper is also the first record of sporophyte plants ofH. pecten-veneris. 展开更多
关键词 new species morphological taxonomy Guangdong Province biogeography distribution
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A Rapid Assessment of Scleractinian and Non-Scleractinian Coral Growth Forms Along the Saudi Arabian Coast, Red Sea
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作者 Abdulmohsin A.Al-Sofyani N.Marimuthu J.Jerald Wilson 《Journal of Ocean University of China》 SCIE CAS 2014年第2期243-248,共6页
In this study we assessed the current status of coral reefs along the Saudi Arabian coast of the Red Sea. Among the three growth forms of Acroporid corals, the branching forms were found to dominate in the Farassan Is... In this study we assessed the current status of coral reefs along the Saudi Arabian coast of the Red Sea. Among the three growth forms of Acroporid corals, the branching forms were found to dominate in the Farassan Islands (44.55%±11.10% cover) fol-lowed by tabular forms in the Doga Islands (ranging between 18%±6.47% and 18.30%±9.47% cover). Digitate forms were rarely found along the coast except at Maqna. Among the five growth forms of non-Acroporid corals, we observed maximum cover of branching forms in the Yanbu offshore area (58.89%±15.11% cover) followed by the Jeddah coast (24.76%±14.04% cover). The Millepora spp., a non-Scleractinian coral, was abundant at all the near-shore sites, such as Jeddah (10.70%±8.21%) and A1-Wajh (9.81%±6.69%). The live coral cover (including both Scleractinian and non-Scleractinian corals) of Saudi Red Sea coast was seen to be higher in the north and gradually decrease towards the south. Principal Component analysis showed that the contribution of Acro- porid corals was greater in the southern region than in the northem and middle regions, but vice-versa in the case of non-Acroporid corals. Bray-Curtis cluster analysis categorized all the study sites into two major clusters with 60% similarity. Among them, one cluster-forming sites from Maqna to Masturah (Northem region) and the second one comprised the middle and southem regions (Jeddah to Farassan Islands), and one outlier Rabigh. 展开更多
关键词 coral reef growth forms Saudi Arabia coral diversity scleractinian coral Red Sea
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Bycatch of Shrimp Fishery in the West Coast of Madagascar: Case of Otolithes argenteus (Cuvier, 1830)
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作者 Isabelle Herisoa Hantanirina Fanomezantsoa Randriarilala +4 位作者 Rivo Nirina Rabearimisa Faniriantsoa Randriaharimino Randriamiarisoa Georges Rafomanana Jean de Neupomuscene Rakotozandriny 《Journal of Environmental Science and Engineering(A)》 2016年第5期230-240,共11页
An increasing interest of the economic operators on the bycatch of shrimp fishery endangers bycatch species to over-exploitation risks. This study provides a better knowledge regarding to the current status of one maj... An increasing interest of the economic operators on the bycatch of shrimp fishery endangers bycatch species to over-exploitation risks. This study provides a better knowledge regarding to the current status of one major component of the bycatches Otolithes argenteus (O. argenteus) caught in the shrimp fishery area along the West coast of Madagascar using the morphometric analysis. Individual body weight and body measurement were carried out on 565 specimens collected from the sale's society of seafood (SOPROMER) in the Capital city. Results show a high proportion of small fishes like as immature young individuals. A "negative allometry" growth type within the juveniles to become "isometric allometry" for the adult, large size was observed. Marine environment is favorable to the development for the whole population of the O. argenteus species. The morphometry approach helped to better understanding of the characteristics and the operating status of the O. argenteus population thus constitute as a tool in establishing a sustainable fisheries management strategy in Madagascar. 展开更多
关键词 Otolith argenteus MORPHOMETRY BYCATCH West coast of Madagascar.
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The Long-Term Morphodynamic of Barito Delta, Southern Kalimantan, Indonesia
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作者 Deasy Arisanty Junun Sartohadi Muh. Aris Marfai Danang Sri Hadmoko 《Journal of Environmental Science and Engineering(B)》 2012年第10期1196-1202,共7页
Barito Delta morphodynamic had contradictive role with its potency and problem. Potency in Barito Delta may support the development of Banjarmasin City, but development of Barito Delta may decrease the capacity of tra... Barito Delta morphodynamic had contradictive role with its potency and problem. Potency in Barito Delta may support the development of Banjarmasin City, but development of Barito Delta may decrease the capacity of transportation in Barito River. Multitemporal topographic map and Landsat satellite image during the period 1862-2008 were used to analyze the long-term delta morphodynamic. The analysis consisted of delta growth, yearly growth, growth orientation, delta shape, and shoreline changes. The research showed that the Barito Delta had developed during the period 1862-2008. Barito Delta had developed to south orientation. The growth of Barito Delta during the period 1862-1946 was 27.82 km^2 or 0.33 km^2/year. However, during the period 1946-1997, Barito Delta growth was 175.82 km^2 or 3.45 km^2/year. Area of Barito Delta decreased during the period 1997-2004. The reduction of Barito Delta area was 4.73 km^2 or 0.67 km^2/year. Area of Barito Delta in years 2004-2008 increased about 3.38 km^2 or 0.84 km^2/year Shoreline during the period 1862-2008 had changed. Accretion occurred in Kuala Lupak River during the period 1862-1997, but erosion occurred during the period 1997-2004. The delta morphodynamics were influenced by human activities in watershed and delta such as landuse change and land degradation. 展开更多
关键词 Morphodynamic Barito Delta topography map Landsat satellite image.
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Fractal Characteristics of Population Canopy Structure of the Mangrove,Bruguiera gymnorrhiza (L.) Lamk
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作者 梁士楚 王伯荪 《Marine Science Bulletin》 CAS 2003年第2期54-61,共8页
The fractal characteristics of the canopy structure of B. gymnorrhiza population are investigated by fractal dimension analysis in the National Shankou Mangrove Nature Reserve. The 3-year-old branches have box dimensi... The fractal characteristics of the canopy structure of B. gymnorrhiza population are investigated by fractal dimension analysis in the National Shankou Mangrove Nature Reserve. The 3-year-old branches have box dimensions between 1.22 and 1.55, showing the complexity degree of branching structure and the ability of occupying and utilizing ecological space. It may be considered that fractal dimension provides a useful index for the study of light utilization efficiencies and growth processes of B. gymnorrhiza. Calculated by using the two-surface method, the fractal dimensions for the crown pattern of individuals with ages of 20 to 50 years range from 2.21 to 2.54, indicating that the filling degree of foliage to a tree crown is relatively low and B. gymnorrhiza has the property of a sun plant. Along with the increase of ages of individuals, the filling degree of foliage to a tree crown changes from high to low, and so does the fractal dimension. The box dimensions obtained from the grayscale curves of population canopy are between 1.47 and 1.61. The greater the box dimension, the more loosely organized the canopy spatial structure, and the more the light spots. The canopy structural information and complexity of a population can be effectively captured by box dimensions obtained from canopy grayscale curves. 展开更多
关键词 MANGROVE B. gymnorrhiza population canopy structure fractals
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Effects of Protective Structures in Morpho-Sedimentological Changes: A Case Study of Rufisque's Coast, Petite C6te, Senegal
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作者 Abdoulaye Ndour Isabelle Niang +4 位作者 Amadou Tahirou Diaw Kader Ba Issa Sakho Badara Diagne Boubacar Fall 《Journal of Shipping and Ocean Engineering》 2014年第9期279-289,共11页
Protective structures, built in the 1980's in order to reduce or stop coastal erosion in Rufisque, involved a modification of the coastal morpho-sedimentary landscape and have intensified the coastal dynamics. The di... Protective structures, built in the 1980's in order to reduce or stop coastal erosion in Rufisque, involved a modification of the coastal morpho-sedimentary landscape and have intensified the coastal dynamics. The diachronic study of beach profiles, before and after the seawalls construction showed that these protective structures accentuated the coastal erosion, with more important sedimentary deficits at the ends of the structures. Today, the Rufisque coast is characterized by a set of sedimentary cells whose morphological evolution and annual sedimentary dynamics are controlled by seasonal forcing: sedimentary deposits in dry season and erosion in wet season. However, this alternation of deposits and erosion phase shows spatiotemporal disparities. These disparities are very marked between a northwestern area characterized by concave profiles and a southeastern area (the bay of Rufisque) characterized by convex profiles and a much more important sedimentary deficit. The results also showed that these methods of shoreline protection are not durable measurements (degradation of the structures) and have exacerbated the vulnerability to coastal erosion as well as those of the coastal populations. 展开更多
关键词 Protective structures coastal erosion Rufisque Petite Cote Senegal.
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