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1.
Shoreline positions established from beach profile surveys combined with wave data are jointly analyzed, as a function of their contribution to coastal processes, to investigate the interaction between waves, shoreline orientation and coastal structures along the Nile delta promontories, Rosetta, Burullus and Damietta. Repeated beach profile surveys along the promontory sectors (64 km long in total) have been analyzed to determine rates of shoreline changes prior to construction (1971–1990) and after construction of protective structures (1990–2000). The behavior of coastline pre- and post-construction indicates that coastal erosion fronting protective structures has declined in the case of the seawalls at the tips of the Rosetta and Damietta promontories, or has been partially replaced by sand accumulation in the case of detached breakwaters at Baltim (east of Burullus promontory) and at Ras El Bar (west of the Damietta promontory). As a consequence, downdrift erosion has been initiated in local areas adjacent to these structures in the direction of longshore sediment transport. The 5-km-long seawall protecting the Rosetta promontory has stopped the dramatic erosion of this highly eroded area (formerly shoreward retreated 88 m/year), with adverse local erosion at its west and east ends, being 3 and 13 m/year, respectively. Similarly, the 6-km-long seawall built on the eastern tip of the Damietta Promontory, still under construction, has nearly stopped the severe erosion, which was formerly 10 m/year. The detached breakwaters at both Baltim and at Ras El Bar have accumulated sand at accretion rates of 37 and 14 m/year, respectively. This sand accumulation is associated with downdrift erosion of 25 and 13 m/year at Baltim and Ras El Bar, respectively. Results reaffirm that the original erosion/accretion patterns along the Nile delta promontories have been reshaped due to the massive protective structures built during the last decade. This reshaping along the examined promontories is generally controlled by the temporal variability in the intensity and reversibility of wave directions and associated longshore currents, coastline orientation and by the existing coastal protection structures. 相似文献
2.
中国制造业分布的地理变迁与驱动因素 总被引：7，自引：1，他引：6
近年来中国制造业分布格局呈现出新的动向。以2004-2005年为转折点,以食品轻纺行业为主的部分制造业部门开始从沿海省份向中西部省份转移,北京、天津、上海、浙江、广东、福建等省份的产业份额明显下降,安徽、江西、湖南、河南、四川等中西部省份的产业份额趋于增加。在地市尺度上,制造业分布变化呈现出"西进北上"的特点,具体表现为产业份额从沿海发达城市转向沿海省份内部发展相对滞后的地市、以及中西部省份内部产业基础较好且本地市场规模较大的地市。中部地区的重点开发区域已成为承接产业转移的重要载体。沿海地区劳动力、土地等要素成本上升导致要素成本的区域差异不断扩大,与此同时中西部地区市场邻近和供给邻近逐步得到改善。沿海地区和中西部地区之间要素成本差异的扩大和贸易成本差异的缩小,使得贸易成本和要素成本的均衡关系发生逆转性变化,这是驱动中国产业分布地理变迁的核心因素。 相似文献
3.
Abstract: Understanding coastal boundaries, connections and drivers of landscape change is integral to effective coastal planning and management. This concept is explored here through case studies representing two very different New Zealand systems: embayed sand beaches in eastern and western open-coast settings; and mixed sand and gravel coast river-mouth lagoons. When framed within a resource and environmental management context these studies indicate that national recognition of the dynamic and interactive nature of coastal environments is a relatively new and amorphous phenomenon in New Zealand and, as such, has been ineffective in driving integrated regional management practices and sustainable coastal outcomes. 相似文献
4.
5.
《Basin Research》2018,30(Z1):248-268
The architecture of the Western Andes is remarkably constant between southern Peru and northern Chile. An exception, however, is present near Arica at 18°S, where the Andes change their strike direction by ca. 50° and the Coastal Cordillera is absent over an along‐strike width of 50 km. Although this feature has been mentioned in several previous studies, no effort has been made yet to describe and explain this peculiar morphology of the Western Central Andean forearc. Here, we propose a large‐scale model to explain the Myr‐long low uplift rate of the Arica Bend concerning seismic coupling and continental wedge‐top basin evolution. New geomorphic and sedimentologic data are integrated with seismicity and structural data from the literature to interpret the post‐Oligocene pattern of uplift, erosion and sediment transport to the trench. Results show that the Arica Bend has been marked by exceptionally low coastal uplift rates over post‐Oligocene timescales. In addition, this uplift anomaly at the Arica Bend correlates with relatively high sediment discharge to the corresponding trench segment since late Oligocene time. We interpret that before 25 Ma, the forming seaward concavity of the subduction zone induced trench‐parallel extension at the curvature apex of the overriding forearc. The subsequent low uplift rate would have then triggered a feedback mechanism, where the interplay between relatively low interplate friction, low coastal uplift and relatively high sediment discharge favoured Myr‐long relative subsidence at the Arica Bend, in contrast to Myr‐long uplift of the Coastal Cordillera north and south of it. 相似文献
6.
基于GIS方法的沿海城市人口变动及空间分布格局研究 总被引：1，自引：0，他引：1
经济社会越发展,人类对海洋的开发力度越大,同时,沿海地区聚集的人口也越多。21世纪以来,沿海城市人口规模及其变化的市别差异较大,个别城市出现了人口自然负增长的态势,总体上沿海城市人口密度显著高于内陆城市,人口迁移流入集中于24个沿海城市,约占沿海城市总数的一半。借助GIS技术,应用空间聚类的方法分析,结果表明:21世纪以来沿海城市人口重心向西南略微移动;人口分布趋于均匀,从人口密度方面看,2010年较2000年在空间上人口聚集程度有所下降。提出了优化沿海地区城市人口分布的对策建议。 相似文献
7.
Assessment of coastal vulnerability to environmental change in Jiangsu coastal plain 总被引：1，自引：0，他引：1
Assessment of coastal vulnerability to future environmental change has been emphasized in coastal nations or regions. The Jiangsu coastal plain, located to the north of the Yangtze River Delta in China, is most vulnerable to sea level rise and exacerbating coastal hazards. This paper develops the method of delimiting vulnerable scope and assessing coastal vulnerability through field observations and sampling and by applying remote sensing and GIS, which are suitable for great river delta and coastal plains with large area, relative complex micro-geomorphology and the protection of seawall. Applying this method, the coastal vulnerability of the Jiangsu coastal plain to relative sea level rise (approximately 50 cm up to the year 2050) and exacerbating storm surges have been assessed. The results show that, up to the year 2050, the Jiangsu coastal plain will probably lose 12.8 % of tidal flats (about 5.8×104 hm2) and 7.9 % of cultivated land (about 7.2×104 hm2). Meanwhile, 2.0 % of population, 3.8 % of original value of fixed assets, 3.2% of GDP (Gross Domestic Product), 40.3 % of salt industry and 5.8 % of aquiculture respectively will be affected due to coastal environmental change. 相似文献
8.
1 IntroductionCoastal areas, with dense population and high urbanization, are highly sensitive to global environmental change. The impacts of coastal environmental changes, such as sea level rise and related disasters exacerbation on socio-economic development of coastal areas, have become a matter of public concern. To study the vulnerable scope and degree of impacts of sea level rise and related exacerbating coastal hazards can provide a scientific basis for lessening the potential losses th… 相似文献
9.
粤琼“老红砂”的岩矿特征与成因研究 总被引：3，自引：0，他引：3
通过野外剖面观察,室内岩矿和沉积学分析,热释光测年分析等,认为粤琼等四纪老红砂为晚更新世晚期海岸风沙作用的产物,其物质来源于邻近的海滩砂,后在湿热的气候环境下风化,造成Ｓｉ,Ｋ,Ｎａ等元素的淋失和Ｆｅ,Ａｌ的富集。 相似文献
10.
Jennifer M. Galloway R. Timothy Patterson Christine T. Doherty Helen M. Roe 《Journal of Paleolimnology》2007,38(4):569-588
Pollen and diatoms preserved in the radiocarbon dated sediments of Two Frog Lake in the Seymour-Belize Inlet Complex of the
central mainland coast of British Columbia document postglacial climate change. Two Frog Lake was isolated from the sea prior
to 11,040 ± 50 yr BP (13,030 cal. yr BP) when the climate was cool and dry, and open Pinus contorta woodlands covered the landscape. These woodlands were replaced by a mixed conifer forest ca. 10,200 yr BP (ca. 12,300 cal.
yr BP) when the climate became moister. A relatively dry and warm early Holocene climate allowed Pseudotsuga menziesii to migrate northward to this site where it grew with Picea, Tsuga heterophylla and Alnus. The climate became cooler and moister at ca. 8,000 yr BP (ca. 9,200 cal. yr BP), approximately 500–1,000 years prior to
sites located south of Two Frog Lake and on the Queen Charlotte Islands, but contemporary with sites on the northern mainland
coast of British Columbia and south coastal Alaska. Climate heterogeneity in central coastal British Columbia appears to have
occurred on a synoptic scale, suggesting that atmospheric dynamics linked to a variable Aleutian Low pressure system may have
had an important influence on early Holocene climate change in the Seymour-Belize Inlet Complex. The transition to cooler
and moister conditions facilitated the expansion of Cupressaceae and the establishment of a modern-type coastal temperate
rainforest dominated by Cupressaceae and T. heterophylla. This was associated with progressive lake acidification. Diatom changes independent of vegetation change during the late
Holocene are correlative with the mid-Neoglacial period, when cooler temperatures altered diatom communities. 相似文献
11.
A coastal dunefield on Groote Eylandt, in the Gulf of Carpentaria, northern Australia, is stratigraphically described and dated using the coarse fraction thermoluminescence dating technique. Four phases of dune activity have been identified: (1) Modern active transverse and parabolic dunes. (2) A parabolic dunefield apparently stabilized less than 2000 yr BP. (3) A parabolic dunefield stablized between 6000 and 4800 yr BP. (4) A basal dunefield unit emplaced prior to 100,000 yr BP.The current dune systems are an expression of dune activation and stabilization events in the Holocene, but were formed from the deflation of an extensive pre-Holocene dunefield. The destruction of the pre-Holocene dunefield appears to have been caused by sea-level rise at the end of the Pleistocene and during the early Holocene. The ages derived from the dunefield accord well with chronostratigraphic investigations of coastal dune systems elsewhere in northern Australia and support theories of regional environmental change during the Holocene. 相似文献
12.
地处全球变化敏感地区的海岸沙地的利用变化及其环境效应日益受到关注。文章通过对海岸沙地利用及其变化研究的发展历程,海岸沙地利用变化研究的案例与技术方法,海岸沙地利用变化所引起的大气环境、水环境、土壤环境、生物环境等方面的环境效应研究等文献的梳理和总结,对国内外海岸沙地利用变化及其环境效应的研究进展进行了综述,并提出了今后研究的主要方向：海岸沙地利用变化未来发展的情景模拟、海岸沙地利用演变驱动机理的定量分析、海岸沙地利用的整体生态环境效应研究、海岸沙地防护林地的合理开发与布局等。 相似文献
13.
气候变化背景下中国风暴潮灾害风险及适应对策研究进展 总被引：1，自引：1，他引：0
风暴潮是沿海地区在强烈的大气扰动条件下产生的异常增水现象,并受海平面上升等因素的影响。中国风暴潮灾害频繁,其中尤以东南沿海地区发生频率较高,灾害损失严重。本文从风暴潮灾害的危险性、承灾体的易损性、综合风险区划3个方面系统总结风暴潮灾害的研究进展及存在的主要问题;并以风暴潮灾情特征及风险评估为基础,探讨气候变化对风暴潮灾害风险的影响及其适应对策。气候变化引起的海平面上升将影响风暴潮的趋势、周期及风险区域,因而亟待开展结合海平面上升等因素的综合风险评估。充分考虑气候变化背景下沿海地区自然条件变化及社会经济发展状况,注重短期与长期相结合,完善风险评估体系。为适度、有序的适应气候变化下风暴潮灾害风险,中国在应急预警机制、工程防御及政策法规等适应能力建设方面不断完善,以提高风暴潮灾害的防灾减灾能力。 相似文献
14.
中国的海岸风沙研究:进展与展望 总被引：5，自引：1，他引：4
较为全面地概括和总结了我国海岸风沙研究的主要进展及其成果,包括我国海岸沙丘的类型、分布、成因与发育模式,海岸现代风沙沉积与古风成砂沉积特征,海岸风沙运动观测结果,海岸风沙灾害现状及其防治等。最后,依据海岸风沙研究发展趋势提出了我国海岸风沙研究近期需要特别关注的课题,包括海岸风沙运动的观测与模拟、全球变化与海岸风沙活动关系以及海岸风沙防护研究等。 相似文献
15.
中国海洋经济转型成效时空格局演变研究 总被引：1，自引：0，他引：1
基于海洋经济转型的内涵,构建包括6个分维度在内的中国海洋经济转型成效测度指标体系,利用粗糙集和灰理论组合赋权综合评价法,对2001-2011年中国海洋经济转型成效进行测度研究,并利用核密度估计及GIS空间分析技术对结果进行时空格局演变分析,结论如下：① 从全国层面来看,2001-2010年中国海洋经济转型整体集中在中低值区域,2010年以来,各区域转型均取得明显成效,海洋经济转型差距逐渐缩小,但整体差距仍然存在。② 从6 个分维度层面来看,海洋经济发展度稳步提高,但空间格局没有显著变化;海洋经济转型度、发展条件支撑度、资源集约利用度、生态环境响应度在空间上呈正向变化趋势,转型成效较为明显;海洋产业就业度呈反向变化趋势,说明转型对海洋产业就业存在挤出效应,对海洋产业就业产生重要影响。③ 中国海洋经济转型的时空格局演变是多种因素综合作用的结果,主要包括资源禀赋、区位条件、产业基础及腹地经济差异等。未来影响各省份海洋经济转型的主要因素包括国家政策、科技水平、海洋管理体制等。 相似文献
16.
以环境库兹涅茨理论为基础,通过对广东省1991―2011年的经济发展与废水排放相关数据进行分析,建立了广东省经济增长与废水排放的环境库兹涅茨曲线（EKC）计量模型。结果表明：1）广东省废水排放总量、生活污水排放量与GDP之间存在较明显的库兹涅兹曲线关系。2）工业废水排放量与GDP之间出现了脱钩效应,工业生产对资源环境压力逐步降低。3）生活污水排放量增长却相对较快,逐渐成为废水排放的主体,致使滨海水体中无机氮与磷酸盐的含量呈现出逐年递增的趋势,滨海地区水质富营养化日趋严重,赤潮发生的频率逐渐增多,直接威胁到滨海地区水体功能的正常发挥。4）从渔获率的年际变化来看：近年来广东省滨海水域生物多样性有所恢复,但形势仍不容乐观。尽管EKC理论表明经济增长最终会改善环境质量,但这是有前提条件的。广东省必须在发展经济的同时,制定合理的经济发展与环境保护政策,建立滨海生态环境保护区,实现区域经济与环境的和谐发展。 相似文献
17.
龙口市海岸带土地利用动态变化分析 总被引：13，自引：0，他引：13
利用多期遥感数据,采用目视解译和人机交互计算机分类技术提取1984至2004年间龙口市海岸带土地利用信息,从土地利用总量变化、土地利用变化速度、土地利用类型之间的相互转化、土地利用类型变化的海岸区位效应等方面分析龙口市海岸带动态变化特点。研究结果表明,20年间龙口市海岸带一半以上的土地类型发生了变化,变化速度逐年增加,后期明显大于前期;转化方向上主要表现在耕地向园地的转化,其次是耕地、园地、林地向建设用地的转化;变化的区位特征是距海越近,海岸带特征地类的变化越明显,反之,距海越远,内陆土地利用变化的特点表现得越突出。 相似文献
18.
中国纺织服装产业的区位迁移 总被引：1，自引：0，他引：1
纺织服装业因其自身产业特点和发展特征, 一直是国内研究的热点, 被认为是最早实现全球产业转移和最具有产业转移特征的重要产业之一。通过构建产业结构变动系数来描绘纺织服装业区位迁移的基本格局, 结果表明:① 纺织服装产业的结构变动相对稳定且集中于东部地区;② 结构变化地域分异明显, 沿海大于内陆, 东部大于中部, 中部又高于西部和东北, 东部沿海的浙江、广东、江苏、山东、上海和福建, 中部的湖北和河南, 以及东北的辽宁, 纺织服装业的结构变化系数均高于全国平均水平, 西部地区的多数省份则较低;③ 结构变动系数的大小取决于当地经济发展、区位性和结构性因素。采用偏离-份额模型将中国纺织服装业发展分解为结构效应和空间效应, 以此阐述中国纺织服装业区位迁移的内在规律。结果表明:① 河南、安徽和江西已经成为东部纺织服装业转移的主要承接地区;② 纺织服装业的区位迁移在竞争效应和纯空间竞争效应上具有一致性, 说明产业的地理分布主要受到区位优势的影响;③ 明显的结构负效应说明纺织服装业的产业结构有待于进一步优化。 相似文献
19.
海岸带土地利用/ 土地覆被变化研究进展 总被引：12，自引：0，他引：12
海岸带地区作为海洋、陆地和大气相互作用的区域, 其环境具有复杂性和多变性的特点, 海岸带地区土地 利用/土地覆被变化( LUCC) 研究是海陆交互作用( LOICZ) 研究的重要组成部分。介绍了海岸带LUCC 研究的目标、 内容以及海岸带LUCC 研究在全球变化研究中的地位和作用, 综述了国内外海岸带LUCC 研究的进展, 指出目前 在海岸带LUCC 研究中主要存在的问题: 即驱动力模型和机制研究相对欠缺; 对气候、水环境等的影响机理不明 确; 对环境脆弱地区的LUCC 研究甚少等。今后应该加强海岸带地区LUCC 物质通量研究、海岸带地区环境之间的 影响模式以及与海岸带区域可持续发展之间的关系模式研究。 相似文献
20.
本文构建了中国地级市工业竞争力评价指标体系, 运用主成分分析法综合评价了中国286 个地级市工业竞争力水平, 研究了中国经济区的工业竞争力水平和空间格局特征。并尝试将集聚和外部联系作为空间要素引入生产函数模型, 探讨不同的工业发展水平下, 综合技术、资本、劳动力和空间各投入要素的贡献程度。研究表明:①经济区工业竞争力水平由高到低依次为东部沿海经济区、南部沿海经济区、北部沿海经济区、东北经济区、长江中游经济区、黄河中游经济区、西北经济区、西南经济区, 各经济区各具独特的空间格局特征。②把空间要素引入生产函数模型是可行的, 并验证了空间要素对产出具有重要影响, 但对于不同的工业发展水平的贡献强度存在差异。③随着工业水平的提高, 要素贡献程度的趋势分别是:综合技术先增大后减小, 劳动力持续减弱, 资本稳步增大, 空间要素则先减小后增大。④在现有工业投入结构下, 强和弱等级城市具有明显的投入规模报酬递增, 而较强和较弱等级没有明显的投入规模报酬递增。 相似文献