Influence of Irregular Coastlines on a Tornadic Mesovortex in the Pearl River Delta during Monsoon Season.Part II:Numerical Experiments

As demonstrated in the first part of this study(Part I),wind-shift boundaries routinely form along the west coast of the Pearl River Delta due to the land-sea contrast of a“trumpet”shape coastline in the summer monsoon season.Through multiple numerical simulations,this article(Part II)aims to examine the roles of the trumpet-shaped coastline in the mesovortex genesis during the 1 June 2020 tornadic event.The modeling reproduced two mesovortices that are in close proximity in time and space to the realistic mesovortices.In addition to the modeled mesovortex over the triple point where strong ambient vertical vorticity was located,another mesovortex originated from an enhanced discrete vortex along an airmass boundary via shear instability.On the fine-scale storm morphology,finger-like echoes preceding hook echoes were also reproduced around the triple point.Results from sensitivity experiments suggest that the unique topography plays an essential role in modifying the vorticity budget during the mesovortex formation.While there is a high likelihood of an upcoming storm evolving into a rotating storm over the triple point,the simulation's accuracy is sensitive to the local environmental details and storm dynamics.The strengths of cold pool surges from upstream storms may influence the stretching of low-level vertically oriented vortex and thus the wrap-up of finger-like echoes.These findings suggest that the trumpet-shaped coastline is an important component of mesovortex production during the active monsoon season.It is hoped that this study will increase the situational awareness for forecasters regarding regional non-mesocyclone tornadic environments.

Computational Quantification of Map Projection Distortion by Fractal Dimension of Coastlines

Maps, essential tools for portraying the Earth’s surface, inherently introduce distortions to geographical features. While various quantification methods exist for assessing these distortions, they often fall short when evaluating actual geographic features. In our study, we took a novel approach by analyzing map projection distortion from a geometric perspective. We computed the fractal dimensions of different stretches of coastline before and after projection using the divide-and-conquer algorithm and image processing. Our findings revealed that map projections, even when preserving basic shapes, inevitably stretch and compress coastlines in diverse directions. This analysis method provides a more realistic and practical way to measure map-induced distortions, with significant implications for cartography, geographic information systems (GIS), and geomorphology. By bridging the gap between theoretical analysis and real-world features, this method greatly enhances accuracy and practicality when evaluating map projections.

Numerical simulations of rip currents off arc-shaped coastlines

The rip currents induced by waves off arc-shaped coastlines are seriously harmful to humans, but understanding of their characteristics is lacking. In this study, the FUNWAVE model was used to calculate the wave-induced currents in the Haller experiment and the ideal arc-shaped coast similar to Sanya Dadonghai, Hainan Province,China. The results showed that the FUNWAVE model has considerable ability to simulate the rip currents, and it was used to further simulate rip currents off arc-shaped coastlines to investigate their characteristics. The rip currents were found to be stronger as the curvature of arc-shaped coastline increased. Coastal beach slope exerts a significant influence on rip currents; in particular, an overly steep or overly mild slope is not conducive to creating rip currents. Furthermore, the rip currents were found to become weaker as the size of arc-shaped coast decreased. When the height and period of waves increase, the strength of rip currents also increases, and, in some cases, wave heights of 0.4 m may produce dangerous rip currents.

A Collaborative Simplification Method for Multiple Coastlines Based on the Hierarchical Triangulation Network Partition

For the current automatic coastline generalization method,only one-line element is considered separately,but the relationship between the nearby elements is not effectively considered.A synergistic simplification method for multiple coastlines based on the hierarchical triangulation network partition(HTNP)is proposed in this paper.Firstly,the constrained Delaunay triangulation is constructed to partition the regions that can be simplified.Then,a hierarchical binary tree model to structure the morphological characteristics of the above several coastlines and the spatial proximity between different coastlines is constructed.Finally,the small curved and curved invisible parts of the coastline are deleted according to the visual constraints,and the narrow part between the coastline itself or the different coastlines is exaggerated appropriately,and the automatic simplification of the coastline is realized.The experimental results show that:①Relationships between the different coastlines are considered,and the shortcomings of considering the coastline separately are overcome;②Under the condition of the multiple coastlines in complex sea areas,the problem of collaborative simplification is solved,the quality of the coastlines are improved obviously,and the proposed method can be applied into more types of coastlines.

Environmental Impacts of Solid Waste Landfills on Natural Ecosystems of Southern Caspian Sea Coastlines

The problem of solid waste landfills on Caspian Sea coastlines is one of the current concerns of the Iranian environmental authorities. Physical and environmental constraints as well as shortcomings in present municipal solid waste management are the main factors for environmental pollution and natural resources destruction in this geographical region. In order to reduce the above problems, this study has been carried out on the basis of a comparative assessment of the existing condition of landfill sites in natural ecosystems. In this study, 48 cities of the region have been investigated. All of them are located in Gilan and Mazandaran provinces. Total daily waste production in the study area is about 1209 tons that are dumped in open spaces and/or in aquatic and terrestrial ecosystems. Surveying of 53 physical, adaptability and constraint parameters as well as hygiene and environmental parameters in the landfills, based on “Monavari-94 Method” indicate that the main problem in all of them is a high groundwater table. In 42% of landfills, the groundwater level is between from 0.5 to 2 meters. This phenomenon may cause severe risks due to the infiltration of leachate into potable groundwater. Indeed, the results of the study show that 87.5% of the landfills are located in areas with unacceptable conditions. In spite of geographical and environmental problems and constraints and as a final alternative in this respect, the need for sanitary and technical solid waste management is the main need of the study areas.

Characterization of some bacterial strains isolated from the Egyptian eastern and northern coastlines with antimicrobial activity of Bacillus zhangzhouensis OMER4

Marine microorganisms were considered to be important sources of marine bioactive compounds.The major objective of the study was to isolate and characterize bacteria with antimicrobial activities from the various marine environment of Egypt.In this respect,thirty-five bacterial isolates were recovered from sediment samples collected from different spots along the Egyptian Red Sea coastline and Alexandria coastline during the summer season of 2017 and 2018.According to the morphological,physiological,and biochemical characteristics,the bacterial isolates were clustered into 13 groups designated as A,B,…,M.And,14 Gram-negative and 21 Grampositive bacteria were determined.The isolated bacterial strains were screened for their potentiality for antimicrobial agent(s)production against ten indicator strains.Strain Mo13 was showed high antimicrobial activity against all empirical strains.Subsequently,the most promising marine bacterial isolate with code MO13 was identified as Bacillus zhangzhouensis OMER4 according to the phenotypic characterization through morphological,physiological,and biochemical tests as well as genotypic characterization through the 16 S rDNA technique.The bioactive components were extracted with ethyl acetate,then analyzed using GC-MS and the substantial component was recognized as phenol,2,4-bis(1,1-dimethyl ethyl).

Coastline changes and tidal current responses due to the large-scale reclamations in the Bohai Bay

China’s Bohai Bay has experienced large-scale land reclamation since 2000.These reclamation projects create a nearshore ecological imbalance and shift sediment transport by changing the tidal current.However,these tidal current changes are not comprehensively understood.In this paper,the coastline changes in Bohai Bay due to reclamation are investigated and the responses of the tidal current are calculated through numerical methods.The results show that the coastline length of the bay increases by more than 500 km from 2000 to 2015 with the largest reclamation rate of 150.9 km^(2)/a.Consequently,the current velocity changes with an uneven distribution near the reclamation due to construction masking and dike protrusion.The tidal symmetry also changes in most nearshore areas,with opposite variations in the current velocity at peak flood and ebb tide.In addition,the tide direction deflects to bypass the reclamation and is usually consistent with the coastline.Harmonic analysis of the dominant M2 tidal constituent shows that the range of the reciprocating current is widely extended.The total influence of the reclamation can reach the-8-m isobaths in Bohai Bay.Changes in the tidal current are the main causes of water environment deterioration.Therefore,the arrangement and structural optimization of reclamation projects should be considered in the future.

Tsunami Hazard Assessment on Qatar Coastline from Makran Earthquakes Considering Tidal Effect and Coastal Landslides Scenarios

To assist the analysis of tsunami hazards for Qatar coastal areas were using numerical model. By Tsunamis waves created from submarine earthquakes of magnitude of (Mw) 8.6 and 9.0 in Richard scale along the Makran Subduction Zone (MSZ) as well as coastal landslides with soil volume of 1.25 to 2.0 km3 along Iranian coast inside the Arabian Gulf is considered. TUNAMI-N2KISR model (Al-Salem) was applied in this study to predict the tsunami propagation and magnitude of Tsunami induced wave heights. The model adopts to solve shallow water equations describing nonlinear long-wave theory. The model also incorporate tidal effect inside the Arabian Gulf as a tsunami travel time from Makran Subduction to Qatar coastline takes more than 9 hours with the tidal range of about 1.6 m during Spring Tide event. For coastal landslides, tsunami generation was simulated using a two-layer numerical model, developed by solving nonlinear long-wave equations. Two-layer model was used to determine initial wave deformation generated by a landslide case. Then TUNAMI-N2KISR was use to simulate tsunami wave propagation. Tsunami waves from landslide scenario arrived after 2.5 - 3 hr with maximum tsunami amplitudes along coasts of Ras laffan-Qatar were 0.8 to 1.0 m. Incorporation of ocean tide is found to impose some small effect on tsunami amplitude at Qatar coastline and nearby areas for the Mw 9.0 earthquake due to small tidal range in this area. In addition, it is found that the tsunami arrival time has become shorter.

基于谷歌地球历史影像的大连市海岸线变化分析

为了研究大连市近40年海岸带环境变迁和演化规律,基于谷歌地球历史影像,采用GIS技术提取和分析了大连市1984-2018年海岸线变化信息.结果显示大连市海岸线增长经历了低-高-低3个阶段,时间节点为2004年和2014年.围(填)海增速与GDP增速曲线具有较强的相关性.从空间来看,大连市海岸线变化主要分布在湾区和河口地区,主要类型为填海造陆区和围海养殖区.其中填海造陆区主要集中在市辖区中南部沿岸和长兴岛开发区,围海养殖区则分散在北部和东部瓦房店、普兰店和庄河等地.

基于遥感影像的水边线提取方法综述

海岸线是体现自然因素和人类活动对沿海环境影响的关键,在沿海资源开发、海岸带综合管理等领域具有重要的应用价值。基于遥感技术的海岸线提取步骤一般是先通过遥感影像提取瞬时水边线,然后对其进行潮位校正。本文针对海岸线分析的重要内容——水边线提取进行综述,主要介绍了遥感影像提取水边线的传统和人工智能两类方法,其中传统的提取方法包括阈值分割法、区域分割法、边缘检测法和面向对象法,人工智能的提取方法包括传统机器学习法和深度学习法。在总结和分析各种具体水边线提取方法的特点和优缺点基础上,展望了未来水边线提取的研究或发展方向。本文认为未来利用遥感影像进行水边线提取可以重点关注基于高分辨率影像的水边线精细提取、基于深度学习方法的水边线全自动提取、不同海岸水边线多类别提取以及基于无人机遥感的水边线提取应用等几个方向。

天绘二号卫星双基SAR模式下海岸线提取研究

海岸线的长度及位置是国家海洋管理重要的基础数据,具有重要的开发和利用价值。本文以天绘二号卫星双基SAR影像为数据基础开展海岸线自动提取技术研究,针对单景SAR强度图含有斑点噪声阻碍判断水体边缘的问题,提出稳健的SAR影像滤波方法,并且联合主辅影像强度图、相干性图中水体区域数据特征进行海岸线识别,解决依赖单一判别信息不准确、不稳健的问题。利用区域生长法和数学形态学方法优化结果,获取最终海岸线提取结果。利用多幅天绘二号数据进行实验,结果表明,利用双基SAR数据本文方法可以改善海岸线提取的实际应用效果。

基于CBAM和Unet的遥感影像水体识别

使用Unet深度学习技术,引入注意力机制CBAM(Convolutional Block Attention Module)动态捕捉图像的关键特征信息,并根据每个通道的重要性自适应地调整注意力权重,增强水体识别模型的表达能力和性能。通过实验验证,相比Unet水体识别模型,CBAM+Unet水体识别模型识别的河流在宽度、走向、轮廓上更接近真实河流,而且对河流的边线识别也更加精细,该模型的准确率、精确率、召回率、F1值、Kappa系数各项指标分别达到98.24%、98.73%、99.32%、99.02%、89.77%,Kappa系数和Unet相比提高8.52%,说明CBAM+Unet水体识别模型具有更高的识别精度和水边线提取能力。

人类活动对辽河口海岸线和海岸带景观演变影响

海岸线和海岸带景观对于维系河口海岸带生态系统稳定意义重大。利用遥感(remote sensing,RS)和地理信息系统(geographic information system,GIS)技术,获取辽河口海岸线1985-2017年Landsat遥感影像数据,对海岸线长度变化、岸线属性变化以及海岸带景观类型演变特征进行分析。结果表明:(1)1985-2017年辽河口海岸线呈淤积的趋势,海岸线总体向海迁移,海岸线类型由天然岸线向人工岸线转变。海岸线长度减少5.09 km,海岸线蜿蜒形态无明显变化。人类活动是辽河口海岸线迁移和转变的主要因素。(2)辽河口潮滩的边缘密度整体下降;道路的斑块密度总体PD上升0.15,最低值为0.01(1985);自然景观斑块所占面积比例逐渐下降,农田的PLAND值逐渐升高;人为景观的面积加权平均斑块分维数指数逐渐变小表明人类活动对辽河口海岸带景观的干扰逐渐变强。(3)1985-2017年间,泥滩和河流面积减少,养殖、城镇、水库、油井、农田、道路等用地面积增长7975.42 hm^(2),增长占比为11.37%。1994年出的现农田和水库岸线,且均由自然岸线转化而来。

基于快速异源配准的高分辨率SAR影像海岛区域正射校正

随着高分辨率合成孔径雷达(SAR)卫星的陆续发射,对天气条件多变的海岛区域进行全天候、全时段的高精度观测已变得可行。作为多种遥感应用的关键前置步骤正射校正,依赖于高精度控制点来纠正SAR影像的几何定位误差。然而,在海岛区域获取符合SAR校正要求的人工控制点不仅成本高,且风险大。为了应对这一挑战,该文首先提出了一种光学与SAR异源影像的快速配准算法,然后基于光学参考底图自动提取控制点,实现了海岛区域SAR影像的正射校正。所提出的配准算法分为两个阶段:首先构建异源影像的共性密集特征,然后在降采样后的特征上进行逐像素匹配,避免了异源影像特征点重复性低的问题。为了降低匹配复杂度,引入了海陆分割掩模以限定搜索范围。接着,对初步匹配点进行局部精细匹配,以减少降采样带来的不准确性。同时,引入海岸线均匀采样点以提升匹配结果的均匀性,并通过分段线性变换模型生成正射影像,确保了稀疏岛屿区域的整体校正精度。该算法在多景海岛区域的高分辨率SAR影像上表现出色,平均定位误差为3.2 m,整景校正时间仅需17.3 s,均优于现有多种先进的异源配准与校正算法,显示出其在工程应用中的巨大潜力。

海岸线的塑造:古尔纳《海边》中的历史反思与世界建构

阿卜杜勒拉扎克·古尔纳,2021年诺贝尔文学奖得主,以东非沿岸为背景展开了文学创作。这片土地不仅是他的故乡,也是他小说中想象世界的重要来源。在他的作品《海边》中,他对海岸线的描绘不仅呈现了一个独特而多元的世界,同时也带来了对殖民历史的深刻反思。古尔纳将海岸线视作一个文化符号,承载着无数故事和命运,同时也反映了殖民历史对当地社会的影响。主人公萨利赫·奥马尔和拉蒂夫·马赫穆德最后在海边的和解不仅是两个人之间的个人故事,更象征着海洋边缘形成的共同体的团结。这种共同体超越了传统的民族概念,建立在共享海洋文化和生活经验的基础上,展现出一种流动共存的状态。古尔纳借此呼吁人们以更加包容和开放的态度对待多元文化的存在。

Research on the Model of Coastline Demarcation and Management

The coastline demarcation and announcement models in China are outlined in this paper. The issues related to the coastline revision system, coastline zoning, coastline usage and the coastline information management are put forward. The concreted research and discussion on these issues are made which are valuable for the coastline management in our country.

海岸带区域用地用海布局规划协调机制研究

海岸带区域用地用海涉及原有海洋功能区划、城乡规划和土地利用规划等多门类空间规划,各类标准和区划混杂,长期以来缺乏科学有效的规划管控,亟需提出解决方法,建立有效机制,总结得出优化海岸带空间和功能布局的合理思路。文章从全域统筹发展的角度出发,对海岸线两侧区域用地用海布局衔接和兼容模式进行了研讨,总结得出用地用海布局协调发展的判定原则。对于用地用海布局不兼容的情形,提出应遵循“生态优先、战略保障”的基本原则来协调海岸线两侧区域功能布局,并提出了划分用地用海分类布局的四个优先度等级;对于不适宜衔接的用地用海布局,提出法定规划调整及编制用地用海清退计划表等相应的解决方案。

Island instantaneous coastline extraction based on the characteristics of regional statistics of multispectral remote sensing image

This study adopted IKONOS remote sensing images and selected spectral characteristic areas, through regional pixel statistics and calculating weight coefficients of each band, processed the images with the spectral normalized method, which made the features of islands, land and water features more obviously in the images. On this basis, the OTUS was used to determine the optimal segmentation threshold, and the normalization image binarization was made, thus the island coastline was extracted. This method used the characteristic curve method to separate the land and water, obtained the binarization images and maintained the original edge effectively. The coastline that was extracted by Binary Morphology was continuous, reliable and high signal-to-noise ratio. The results showed that this method could extract the coastline fast, simply and effectively, which had the practical value.

Eco-sensitivity Analysis Methods in the Planning of Qinglong Mountain Scenic Area

By studying the Qinglong Mountain in southeastern suburb of Wuhan City, relevant information are obtained by applying GIS, weight of each index is acquired via Delphi method and AHP, then an evalution model is established for the assessment of comprehensive sensitivity, and finally eco-sensitive area of each level is determined to provide objective support for the ecological planning of Qinglong Mountain Scenic Area.

1990–2020年中国广西海岸线遥感监测数据集

广西南临北部湾,是“一带一路”交汇的重要门户,拥有丰富的沿海港口资源、海洋生物资源、滨海旅游资源。对于海岸线位置变化和类型转换的遥感监测,可为海岸带的可持续发展和管理提供了宝贵的科学数据支持。本文采用1990–2020年5个时段的Landsat TM/OLI数据,对广西沿海地区进行海岸线提取研究。利用Arc GIS 10.2软件对海岸线的位置进行可视化解译,然后进一步将海岸线划分为人工和自然海岸线两个主要类别和生物质海岸线、砂质海岸线等6个二级类别。本数据集具有时间序列长、精度高、海岸线类型全面和聚焦2015年(可持续发展元年)前后海岸线变化趋势的特点,可用于海岸线时空分布特征和海陆格局演变的研究。