海岸线变化速率计算方法及影响要素分析   总被引：6，自引：0，他引：6  

吕京福  印萍  边淑华  庄振业 《海洋科学进展》2003,21(1):51-59

计算历史时期海岸线变化率常用的数学方法有端点法、平均速率法、线性回归法和折剪法。对于线性均变海岸，这几种方法的计算结果之间差异很小，反映的岸线变化趋势比较一致，但对于振荡性或过渡性海岸，计算结果之间有较大的差异。端点法和平均速率法能较好地反映长期岸线变化的总趋势；线性回归法有助于反映海岸变化的过程和规律性；折剪法则可以发现并删除数据序列中的不稳定因素，减小这些异常值的影响。平均速率法在引入最小临界时间概念后，可以平滑突发事件对总计算结果的影响。若引入最小临界时间前后的计算结果有较大变化，则应引起对海岸变化过程中的短期事件的关注。对线性均变海岸，在实际工作中可以根据从简有效的原则选择计算方法，而振荡性和过渡性海岸则应综合使用各种计算方法，尽量以多元回归法取代线性回归法来反映岸线变化规律。计算中使用的数据总量和取样频度、总采样时间长度及数据的精度均会影响到计算结果的精度。以山东日照的2个岸段为例，分析了过去20a间岸线的长期观测资料。结果表明，影响2个岸段演化的因素和2个海滩的发育过程明显不同。第一岸段为典型的线性均变海岸，各数学方法计算结果基本一致，根据过去20a的资料计算得到的岸线变化率，可以作为未来岸线变化预测的依据。而第二岸段则明显受到人为海岸活动的控制，不同方法计算的岸线变化率明显不同，岸线发展过程中的短期振荡性显著，根据历史观测资料计算的海岸线变化速率，仅可作为未来岸线变化趋势预测的背景资料，进一步的监测是科学预测未来岸线变化的基础。  相似文献   

气候变化对北方农牧交错带界线变迁影响的定量探测方法研究   总被引：4，自引：1，他引：3  

史文娇  刘奕婷  石晓丽 《地理学报》2017,72(3):407-419

气候对北方农牧交错带界线变迁的定量影响是目前生态脆弱敏感区对气候变化响应领域的研究热点问题。前人已在气候变化对农牧交错带界线的定性影响方面有较为深刻的认识,但仍缺乏在时间和空间上对气候贡献率进行有针对性的定量辨识。本文利用1970年以来长时间序列的国家气象站点数据和土地利用遥感解译数据,分别提取了基于气候要素和土地利用的20世纪70年代、80年代、90年代和21世纪前10年4个时期的北方农牧交错带界线,通过垂直和水平方向变动探测方法（FishNet）和界线变迁方向变动探测方法（DSAS）对气候界线与土地利用界线的时空变化进行探测,定量分析了不同时期气候对农牧交错带界线变迁影响的贡献率。结果表明,气候与土地利用界线空间分布格局及气候贡献率在不同时期、不同区域差异较大,在西北地区变幅最小,东北地区变幅最大。在大兴安岭东南缘农田控制水源涵养生态功能区西北段以及内蒙古高原东南缘农、林、牧业生态—生产功能区西北段,气候与土地利用界线空间耦合关系最为密切,在该地区基于FishNet方法下水平方向上气候贡献率达10.7%~44.4%,垂直方向上达4.7%~55.9%;基于DSAS方法下气候贡献率为1.1%~16.8%。两种方法探测结果大部分趋于一致,但DSAS方法精度高,适用于小范围精确探测;FishNet方法更简单,适用于精度要求不高、快速直观的统计分析。本研究可为北方农牧交错带内农牧业生产适应气候变化、合理开发土地生产潜力、保护农牧交错带区内生态环境提供科学依据和指导。  相似文献   

Spatio-temporal analysis of decadal-scale patterns in barrier island response to storms: Perdido Key,NW Florida     

Ravi D. Sankar  Joseph F. Donoghue  Stephen A. Kish 《自然地理学》2018,39(2):166-195

The ability to accurately quantify shoreline variability is essential in order to establish aggressive mitigation strategies, based on recent global climate change projections. This investigation employed a suite of coastal data (topographic maps, aerial photography, satellite imagery and lidar) to establish decadal trends of shoreline movement along Perdido Key, a sandy barrier island off Florida’s northwest coast. The technique used to detect morphologic change with time was a recently developed tool, Analyzing Moving Boundaries Using R. This innovative methodology improves our understanding of the evolution of coastal systems by modeling shoreline variance using a method that is sensitive to shoreline shape. Results show that the barrier shoreline is a highly dynamic feature with distinct zones of erosion and accretion that are pervasive over time. In general, the island is displaying a mechanism of rotational instability with the eastern half retreating, and the western portion advancing. The inflection point, around which this rotational shifting is taking place, lies at the center of a Pleistocene headland located along the island’s midpoint. The results of this study suggest that coastal evolution along the island may be meta-stable, with trends in shoreline variance corresponding mainly to discrete storm events in time.  相似文献   

断陷湖盆陡坡带陆相层序地层的“沉积滨线坡折”问题探讨?   总被引：10，自引：2，他引：8       下载免费PDF全文

胡受权  郭文平  颜其彬  刘树根  童崇光  杨凤根 《古地理学报》2000,2(4):20-29

本文在分析断陷湖盆陡坡带不同构造部位的可容空间变化规律及其沉积响应特征的基础上,探讨了断陷湖盆陡坡带参照井选取的可容空间机理,并阐明了参照井的选择原则;根据参照井处的沉积相迁移特征及体系域叠置样式,建立了在参照井的背景下,Ⅰ型与Ⅱ型陆相层序划分及其层序界面判识的标准,以及低水位体系域（LST）、水进体系域（TST）、高水位体系域（HST）及水退体系域（RST）的识别模式。本文以泌阳断陷双河～赵凹地区下第三系核三上段为例,采用泌207井为参照井,对研究区目的层段开展了断陷湖盆陡坡带陆相层序地层学的尝试性研究,并编制了研究区目的层段的陆相层序地层等时框架模式。研究结果表明,采用选取参照井的办法,可以有效地解决断陷湖盆陡坡带陆相层序地层分析中的“沉积滨线坡折”问题。  相似文献   

官厅水库的遥感动态变化探测及边岸稳定性判别     

王志刚  王净 《遥感学报》2003,7(3):328-331

利用TM卫星多时相数据，采用变化探测技术研究了官厅水库1988—2001年时间段库区边岸的动态变化。对库区淤积、边岸侵蚀等问题进行了探讨；结合水位差数据，提出边岸坡度和边岸稳定性的遥感时空分析方法和判据；分析了上述问题对官厅水库水资源利用的影响。边岸稳定性判别方法可应用于湖泊、海洋的滩涂地区。  相似文献   

Challenging assumptions of future coastal habitat development around the UK     

Julian D. Orford  John Pethick 《地球表面变化过程与地形》2006,31(13):1625-1642

One habitat management requirement forced by 21st century relative sea‐level rise (RSLR), will be the need to re‐comprehend the dimensions of long‐term transgressive behaviour of coastal systems being forced by such RSLR. Fresh approaches to the conceptual modelling and subsequent implementation of new coastal and peri‐marine habitats will be required. There is concern that existing approaches to forecasting coastal systems development (and by implication their associated scarce coastal habitats) over the next century depend on a certain premise of orderly spatial succession of habitats. This assumption is shown to be questionable given the possible future rates of RSLR, magnitude of shoreline retreat and the lack of coastal sediment to maintain the protective morphologies to low‐energy coastal habitats. Of these issues, sediment deficiency is regarded as one of the major problem for future habitat development. Examples of contemporary behaviour of UK coasts show evidence of coastal sediment starvation resulting from relatively stable RSLR, anthropogenic sealing of coastal sources, and intercepted coastal sediment pathways, which together force segmentation of coastal systems. From these examples key principles are deduced which may prejudice the existence of future habitats: accelerated future sediment demand due to RSLR may not be met by supply and, if short‐ to medium‐term hold‐the‐line policies predominate, long‐term strategies for managed realignment and habitat enhancement may prove impossible goals. Methods of contemporary sediment husbandry may help sustain some habitats in place but otherwise, instead of integrated coastal organization, managers may need to consider coastal breakdown, segmentation and habitat reduction as the basis of 21st century coastal evolution and planning. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

塔中志留系下沥青砂岩段风暴沉积的砂体研究   总被引：2，自引：0，他引：2  

高志勇  朱如凯  郭宏莉  何东博 《古地理学报》2006,8(4):477-485

塔中志留系下沥青砂岩段沉积砂体的类型有滨岸砂、浅海砂坝和陆棚砂3种类型，正常条件下沉积的滨岸砂体具低角度交错层理和少量波痕，呈现出由泥岩-粉砂岩-细砂岩-中细砂岩的反韵律变化特征。风暴作用下，滨岸砂体沉积呈正韵律，多由泥砾向上变化为粉、细砂，生物建造较少，具多方向的低角度板状交错层理、丘状层理。正常条件下沉积的陆棚砂体、浅海砂坝砂体岩性较均一，见交错层理，粒级变化不甚明显，多为粉、细砂岩，以反韵律为主。风暴作用下，砂体底部多具撕裂状泥砾，向上呈正韵律粒序演化，并具侵蚀面、槽状交错层理与丘状层理等特征。风暴作用下的滨岸沉积单砂体相对较厚，一般厚6～13m，宽约数十米，浅海砂坝和陆棚砂的单层砂体相对较薄，厚约3～8m，砂体规模较正常条件下沉积的砂体规模增大。此3类砂体在空间展布上极具规律性，垂向上砂体类型由下而上为滨岸砂-浅海砂坝-陆棚砂的交替演化序列；平面上由海洋向陆地方向砂体类型依次为陆棚砂体-浅海砂坝-滨岸砂体。  相似文献   

Interplay between shoreline migration paths, architecture and pinchout distance for siliciclastic shoreline tongues: evidence from the rock record     

TORE M. LØSETH  RON J. STEEL†  JEFF P. CRABAUGH‡  MAIJA SCHELLPEPER‡ 《Sedimentology》2006,53(4):735-767

Facies, geometry and key internal stratigraphic surfaces from eight Cretaceous and Eocene clastic shoreline tongues have been documented. The regressive parts of all the studied tongues represent storm‐wave influenced strandplains, deltas or fan‐deltas, and the regressive shoreline trajectories varied from descending to ascending. The transgressive parts of the tongues are dominated by either estuarine or coastal‐plain deposits. The distance from the coeval, up‐dip non‐marine deposits to the basinward pinchout of amalgamated shoreface sandstones, measured along depositional dip, is here termed the sand pinchout distance. The study shows that the angle of regressive‐to‐transgressive turnaround (defined by the angle between the regressive and subsequent transgressive shoreline trajectories) and the process regime during turnaround largely control the sand‐pinchout distance. The amount of transgressive erosion can also partly control the pinchout distance, but this parameter was comparable for the different examples presented here. If the type of depositional system at turnaround and the depth of transgressive erosion are constant, small angles of turnaround are associated with large pinchout distances, whereas larger angles of turnaround result in smaller pinchout distances. The model developed allows sand‐pinchout distance to be predicted, using data for the landward parts of shoreline tongues. The dataset also shows that steeply rising (aggrading) shoreline trajectories tend to produce more heterolithic sandstone tongues than those formed by lower‐angle trajectories.  相似文献   

The Composite Nature of the Provo Level of Lake Bonneville, Great Basin, Western North America     

Dorothy Sack 《Quaternary Research》1999,52(3):316

Deposits of a transgressive-phase Lake Bonneville stillstand or oscillation are found just below the elevation of the regressive-phase Provo shoreline at numerous exposures throughout the Bonneville basin. Existence of these subProvo shoreline deposits provides a new explanation for the massive size of Provo depositional and erosional landforms, which can no longer be explained by a long stillstand at the Provo shoreline. Provo coastal landforms are large because they are superimposed on subProvo landforms. Results also help to clarify divergent interpretations regarding the relative age of the Provo shoreline and the number of times it was occupied by the water plane. Occupation of approximately the same level during both the transgressive and the regressive phase of Lake Bonneville may be coincidental, or it may indicate that a bedrock sill controlled outflow at subProvo as well as Provo time. Rise to the Bonneville level could have occurred after massive slope failure plugged the outlet pass.  相似文献   

Impact of river training walls on adjacent beaches, Ballina, New South Wales, Australia     

黄海军 《中国海洋湖沼学报》1999,17(1):41-48

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