Simulation of the interactions between gravity processes and contour currents on the Algarve Margin (South Portugal) using the stratigraphic forward model Sedsim     

T. Salles  E. Marchès  C. Griffiths  T. Mulder 《Sedimentary Geology》2010,229(3):95-274

The margin of the Gulf of Cadiz is swept by an intermediate current the Mediterranean Outflow Water (MOW) flowing from the Mediterranean to the Atlantic. On the northern margin of the Gulf (Algarve Margin, South Portugal) the MOW intensity is low, and fine-grained contourite drifts are built up with an alongslope alignment. Recent sedimentological studies emphasize the presence of complex process interactions resulting in the formation of a unique depositional architecture. Alongslope processes related to contour currents generate contourite drift, while downslope processes form canyons and channels aligned on deep faults. This paper uses a combined oceanographic and geological dataset to simulate the different types of interactions between gravity processes and contour currents, which were evidenced on this margin. An extrapolation of the contour current intensity has been used based on the present day velocity field and sea-level fluctuations over the simulated geological time-scale. According to our model results, the construction of the contourite drift is closely linked to contour current velocities and directions, the types of sediments transported and the existing topography. Using modern sedimentological understanding of the area, we have correlated gravity flow's strongest activity to sea level lowstand periods mainly due to a closer connection between canyon's mouth and river or deltaic systems. The simulated gravity flows are initialized at different locations and times on the margin depending on the preserved lobes retrieved from seismic analysis. Their resulting morphological features are identified as perched-lobes with volumes and forms close to the ones observed on Portimão and Lagos Drifts. This study provides a process-based understanding of the construction of contourite system and a physical evaluation of the interactions between gravity flows perpendicular to the slope, and alongslope processes. In addition, it shows the influence of autocyclic factors in the construction of contourite sedimentation, which is important to consider in future sedimentary paleo-reconstruction interpretations.  相似文献   

Cartographic generalisation of lines based on a B‐spline snake model     

E. Guilbert  E. Saux 《International journal of geographical information science》2013,27(8):847-870

The automation of cartographic map production is still an important research field in Geographical Information Systems (GIS). With the increasing development of monitoring and decision‐aid systems either on computer networks or wireless networks, efficient methods are needed to visualise geographical data while respecting some application constraints (accuracy, legibility, security, etc.). This paper introduces a B‐spline snake model to deal with the current operators involved in the cartographic generalisation process of lines. This model enables us to perform those operators with a continuous approach. In order to avoid local conflicts such as intersections or self‐intersections, the consistency of the lines is checked and discrete operations such as segment removal are performed during the process. We apply the method to map production in the highly constrained domain of maritime navigation systems. Experimental results of marine chart generalisation yield some discussions about generalisation robustness and quality.  相似文献   

流域面雨量的计算方法   总被引：3，自引：0，他引：3  

李飞  田万顺 《河南气象》2003,(3):20-21

经对面雨量的几种计算方法对比分析，确定了以等雨量线法为计算流域面雨量的方法，同时对于计算方法进行了部分优化，并应用于业务中。  相似文献   

坡地开发中的植物篱技术   总被引：6，自引：0，他引：6  

李阳兵  谢德体  杨朝现 《热带地理》2001,21(2):121-124,130

论述了植物篱在我国坡地开发中的地位、作用、选取标准及在坡地开发中的其它应用，认为植物篱应是控制川中丘陵遂宁组母质区水土流失的主要手段。  相似文献   

基于AutoCAD15的等值线圈的自动绘制方法     

张冬明  芮小平等 《江苏地质》2001,25(1):33-36

在AutoCAD15的环境下利用VBA（Visual Basic Application)宏语言编程实现等值线图自动绘制是一个崭新的课题。分析了该课题的意义。介绍了等值线绘制的原理以及方法和过程，并给出了由程序自动绘制的等值线实例。实例表明，该方法能够获得高质量的等值线圈。  相似文献   

利用绘图软件分析离散点资料的一种方法     

张存杰  白虎志 《干旱气象》1997,(3)

将ＮＣＡＲ和ＳＵＲＦＥＲ两种绘图软件相结合，成功地实现了在特定区域内离散点资料的等值线分析和地图叠加。  相似文献   

使用Surfer Automation实现海洋要素等值线图的批量绘制   总被引：1，自引：0，他引：1  

王冠琳  胡筱敏  熊学军  韩磊  云升军 《海洋技术学报》2007,26(2):70-75

介绍了基于Automation对象技术的使用程序控制Surfer自动绘图的方法,使用Surfer自带的Scripter实现海洋要素等值线图的批量绘制,为在海洋科学研究中批量绘制等值线图提供了一种简捷、高效的途径。  相似文献   

ArcMAP中利用TIN检查1︰5万DLG数据等高线点线矛盾的方法探讨     

WU Biao YING Guo-wei LI You-ming ZHANG Heng-wei 《四川测绘》2008,(5)

通过对国家1︰5万DLG更新数据的生产实践,提出在ArcMAP中利用TIN检查1︰5万DLG数据等高线点线矛盾的方法,文中详细探讨了检查的基本原理、思路以及在VB.NET中代码实现的过程。  相似文献   

深水牵引流沉积研究进展与展望   总被引：5，自引：0，他引：5  

何幼斌  罗顺社  高振中 《地球科学进展》1997,(3)

深水牵引流沉积是继深水重力流沉积之后发现的又一种新的深水沉积类型，目前已发现的深水牵引流沉积包括等深流沉积和内潮汐、内波沉积两种类型。综述了深水牵引流沉积的研究历史、现状与进展，指出了其存在的问题及发展趋势。  相似文献   

科氏力作用下涡旋运动的等值线动力学   总被引：1，自引：1，他引：1       下载免费PDF全文

罗哲贤 《气象学报》1993,51(4):394-404

本文提出了在科氏力作用下,单圈常值涡旋运动等值线动力学的计算公式。用这些公式实施了四组计算,结果与以往动力学分析和数值试验的结论定性一致,数值也较为合理。  相似文献