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基于杭州湾北岸龙泉—南竹港弧形岸段实测岸滩断面与长江入海控制站大通站年输沙量资料,对杭州湾北岸岸线的变化及其趋势进行探讨。研究结果表明：受长江入海泥沙减少以及热带气旋和人类活动作用等影响,近10年来杭州湾北岸岸滩处于侵蚀状态。灰色关联分析进一步揭示,杭州湾北岸不同等深线的进退对长江入海泥沙减少的响应在时间尺度上有一定的滞后。同时,不同等深线的进退亦展现较强的相关性特征。鉴于此,利用大通年输沙量和不同等深线进退的耦合关系,进一步构建了基于长江入海泥沙和杭州湾北岸等深线变化的径向基神经网络岸线预报模型,其中模型输入向量为当年大通站年输沙量和杭州湾北岸-3m、-5m、-8m等深线距离大堤的位置,输出向量为次年0m岸线距离大堤的位置。经检验,构建的径向基神经网络岸线预报模型误差小于20%,可用以预报杭州湾北岸岸线的动态变化。 相似文献
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基于长江中游沿岸地质环境条件及过江大桥场地建设基本要求,优选地形地貌、工程地质条件及区域稳定性3个评价因素,运用层次分析法开展长江中游沿岸过江大桥工程场地建设适宜性评价,将长江中游沿岸过江大桥工程分为适宜开发岸线、较适宜开发岸线、一般适宜开发岸线及非优先开发岸线4个等级。长江中游沿岸地区以较适宜开发岸线和一般适宜开发岸线为主,长度分别为625.19 km和598.99 km,分别占岸线总长度的31.35%和30.04%。针对长江中游不同等级岸线的地质特征,提出了相应的地学建议,为长江中游沿岸过江大桥优化选址提供地学指导,进一步促进长江经济带国土资源空间规划与岸线资源保护利用工作的开展。 相似文献
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基于长江中游沿岸地质环境条件及过江大桥场地建设基本要求,优选地形地貌、工程地质条件及区域稳定性3个评价因素,运用层次分析法开展长江中游沿岸过江大桥工程场地建设适宜性评价,将长江中游沿岸过江大桥工程分为适宜开发岸线、较适宜开发岸线、一般适宜开发岸线及非优先开发岸线4个等级。长江中游沿岸地区以较适宜开发岸线和一般适宜开发岸线为主,长度分别为625.19 km和598.99 km,分别占岸线总长度的31.35%和30.04%。针对长江中游不同等级岸线的地质特征,提出了相应的地学建议,为长江中游沿岸过江大桥优化选址提供地学指导,进一步促进长江经济带国土资源空间规划与岸线资源保护利用工作的开展。 相似文献
4.
津冀海岸线现状、变化特征及保护建议 总被引：1，自引：0，他引：1
根据覆盖全区的3期遥感影像和实地调查,以及对滨海新区和滦河口2个典型区更深入的案例研究(包括回溯至1870年、1950年的基准岸线及逐年遥感信息),对津冀沿海海岸线现状进行解译和分类,并分析岸线变化特征及成因。津冀沿海现状岸线总长度894km,可以划分为自然岸线、半开发岸线和人工岸线3类,长度分别为90km、329km和475km。1950年以前为自然因素主导的岸线变化,1950年以后变为人类活动主导的岸线向海推进,逐渐加强的人类活动至2010年达到顶峰。在全球海面上升和区域地面下沉的大背景下,海岸线的自然演化趋势应该是向陆蚀退,但是人类活动主导的岸线变化却表现为违反自然趋势的向海推进。今后,向海推进最前沿的围海造陆区将受到来自海洋越来越强烈的影响,亟需加强监测和防护。兼顾环境保护与开发两方面的长远需求,建议赋予海岸线新的定义与内涵,划定岸线保护红线,恢复部分岸线的自然属性。 相似文献
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根据1954～2001年的航卫片遥感信息,对长江皖江段的岸线特征及变化进行了调查和分析。航卫片解译,长江皖江段南、北岸线长度分别为405.4km（右岸）和438.8km（左岸）,岸线总长844.2km。根据遥感影像特征和野外调查,将皖江岸带（线）划分为侵蚀岸（冲刷岸）、淤积岸和稳定岸3种类型,其中冲刷岸长426.4km,占岸线总长度的50.5%,左岸大于右岸;淤积岸长198.4km,占岸线总长度的23.5%;稳定岸长219.4km,占岸线总长度的26.0%。根据1954年、1969年、1975年和1986年4个时期的航片资料的对比解译,对1954～1969年、1969～1975年和1975～1986年3个时间段的岸线摆动幅度和速率进行了计算,从中发现,河道岸线的摆动主要是左岸侵蚀后退,段内岸线年平均变形强度在50m以上的有7处,在100m以上有2处。岸带变化的基本特征是:主河道长期右移,近期以左移为主;江心洲的平面变化复杂,汊道河段岸线变化强烈;鹅头形分汊河段演变具周期性特点。 相似文献
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Landsat-TM遥感影像岸线变迁解译研究--以九龙江河口地区为例 总被引：2，自引：2，他引：2
陶明刚 《水文地质工程地质》2006,33(1):107-110
利用遥感与GIS技术相合的手段，在分析九龙江河口地区地物波谱的基础上，对研究区两期遥感影像（1986年6月与2000年5月的陆地卫星Landsat—TM资料）进行解译和岸线提取。通过与20世纪70年代的地形图进行对比分析，发现九龙江北、西溪过河口大沙洲后分成北、中、南3个支流入海，其中以浒茂洲两侧的支流岸线变化最大；海门岛至口门段河口两侧岸线也有不同程度的变化；厦门西港海区是本研究区岸线变化最大的区域。文章最后对岸线变迁和河口淤积进行了初步的分析。 相似文献
7.
《中国地质调查》2019,(5)
基于长江中游沿岸地质环境条件及过江大桥场地建设基本要求,优选地形地貌、工程地质条件及区域稳定性3个评价因素,运用层次分析法开展长江中游沿岸过江大桥工程场地建设适宜性评价,将长江中游沿岸过江大桥工程分为适宜开发岸线、较适宜开发岸线、一般适宜开发岸线及非优先开发岸线4个等级。长江中游沿岸地区以较适宜开发岸线和一般适宜开发岸线为主,长度分别为625.19 km和598.99 km,分别占岸线总长度的31.35%和30.04%。针对长江中游不同等级岸线的地质特征,提出了相应的地学建议,为长江中游沿岸过江大桥优化选址提供地学指导,进一步促进长江经济带国土资源空间规划与岸线资源保护利用工作的开展。 相似文献
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认识崇明东滩岸线的演变规律,对于崇明东滩湿地的保护和利用具有重要意义。利用面向对象的方法,选取1987年至2006年中的6景Landsat-5 TM卫星影像数据,解译出对应年份的东滩岸线。为了对较复杂的非平直岸线的变化进行建模,提出了基于地形梯度的正交断面方法,构建了基于图形学的分析预测模型,对岸线的演变进行分析,预测了2010年和2015年的岸线位置。结果显示：（1）崇明东滩以东南角节点为界,分为南侧的侵蚀岸段和其余的淤涨岸段,总体淤涨速率有减慢趋势,最大侵蚀速率为22.0 m/a,最大淤涨速率为247.2 m/a;（2）北侧自东旺沙水闸向东约4 km长的岸段存在明显的冲淤交替现象;（3）岸线演变受抑制区段都位于东滩两侧岛影缓流区的边界;（4）由于岸外东南侧发育有10 m深槽,除非有特殊的水动力条件出现,东滩未来的岸线将偏向东北方向演变。 相似文献
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北支河槽容积变化是北支河道演变趋势在定量上的直接表现,河道边界条件和河床泥沙运动是影响河槽容积变化的主要因素。收集1986—2013年长江口北支河道年实测地形资料,利用GIS技术建立不同时期水下数字高程模型,进行北支河槽容积变化和河床冲淤变化特征分析。结果表明,北支岸线圈围和泥沙淤积导致了1986年以来河槽容积萎缩。北支河槽0m线以下容积共减少约7.110亿m3,岸线圈围引起河槽容积减少4.000亿m3,占比56.3%;泥沙淤积引起的河槽容积减少3.110亿m3,占比43.7%。具体而言,北支上段河槽容积萎缩主要是泥沙淤积所致,其航道开发综合利用应遵循上段的泥沙运动规律特点;中段则是边滩圈围和沙洲并岸引起,边界调整后束流作用加强,河床冲刷,断面形态调整后水深条件更加有利于中段的航道利用开发;下段是泥沙淤积和边滩圈围共同影响所致,泥沙淤积影响略大,但下段沿北岸-5m深槽始终存在且稳定,具备航道开发利用的河势基础,且南侧河道边界仍具有可圈围的余地。 相似文献
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Guboglo M. N. 《GeoJournal》1980,4(1):53-58
International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen. 相似文献
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Jiayu Rong Michael Melchin S. Henry Williams Tatyana N. Koren Jacques Verniers 《《幕》》2008,31(3):315-318
The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs. 相似文献
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Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth
B. P. Kondratyev 《Astronomy Reports》2017,61(8):709-714
It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T 3 = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″. 相似文献
14.
Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base. 相似文献
15.
Fouad N. Ibrahim Dr. 《GeoJournal》1988,17(1):133-141
Taking the example of W Sudan, an analysis of the climatic incidents leading to the two recent famine disasters is made. On this natural background, the human side is investigated. Focus is directed towards the fragile economic structure of the famine-prone population groups. An early-warning system for famine in the Sahelian Zone is proposed taking grain production and storage, livestock development and the relationship between the prices of livestock and grain as major indicators. 相似文献
16.
东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。 相似文献
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郯庐断裂南段研究进展与断裂性质讨论 总被引：13，自引：3，他引：13
据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。 相似文献
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The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads 总被引：3，自引：1，他引：2
Clemente Irigaray Francisco Lamas Rachid El Hamdouni Tomás Fernández José Chacón 《Natural Hazards》2000,21(1):65-81
In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning. 相似文献