Numerical simulations of the coastal effects of tsunami waves caused by the 1993 Hokkaido-Nansei-Oki earthquake

Generally,tsunami waves become hazardous only when approaching the coast.Studying the runup and inundation of tsunami waves is important for understanding the tsunami evolution and for tsunami hazard assessment.Here,we simulated the 1993 Hokkaido-Nansei-Oki(HNO) tsunami using a finite-difference model based on nonlinear shallow-water equations.We focused on the runup and inundation of tsunami wave propagation onto coastal area of Okushiri Island near Hokkaido,Japan,and investigate the relationship of different runup heights with the morphology and bathymetry of the seashore.In the simulation,a nested 4-layer grid system and moving boundary technique are adopted to study runup and inundation.The calculated tsunami heights and inundations in the region agreed well with field measurements.The local bathymetric and topographic characteristics had a first-order effect on the runup.Numerical experiments show that the focusing of certain local bathymetric features would amplify both wave height and current velocity remarkably.The results show that computation on dense grids is necessary to reproduce the observed runup heights,and inundation velocity is an important factor preventing tsunami devastation.In addition,we discussed the potential capability of sediment transport to illustrate the impact of tsunami waves on coastal geomorphology.

RELATIVE SEA LEVEL RISE AND ITS EFFECTS ON ENVIRONMENT AND RESOURCES IN CHINAS COASTAL AREAS

Due to global climate warming and natural and man-made land subsidence etc., relative sea level rise in the coastal plains of China will exceed 2-3 times over the golbal mean value during the first half part of the 21st century. It will result in a series of adverse impacts on evolution of natural environment and socioeconomic development of the coastal area. This paper analyses environmental and resource effects induced by relative sea level rise in China's coastal areas on the basis of rough estimate of future relative sea level rise. These effects include inundating tidal flat and wetlands and increase in inundated risk of coastal habitable land,exacerbating storm surge. coastal erosion, flooding and salt water intrusion hazards.as well as endangering land. water. tourism and living resources and their utilization.

Research Advances on Marine Ecological Effect and Repairing Techniques of Coastal Mangrove Wetland

Coastal mangrove wetland is one of the areas whose global ecological environmental conditions have severely changed. Its ecosystem is vulnerable to damaged. The international community has paid attention to conservation and wisely use of mangrove wetland. This paper describes five parts of coastal mangrove wetland at home and abroad,including seawater's purification effect of nitrogen and phosphorus,seawater's adsorption of heavy metals,the functions of carbon sequestration and climate regulation,implant restoration techniques and the status of protection and management. And research trends of coastal mangrove wetland were proposed,in order to provide reference for the restoration and protection of China's coastal mangrove wetland.

Coastal afforestation effects on soil properties at Hatiya in Bangladesh

An exploratory study was conducted in the coastal plantation （12- and 17-year-old Sonneratia apetala） of Char Alim and Char Piya and on their adjacent barren lands at Char Rehania and Char Nurul Islam in Hatiya of Noakhali district, in Bangladesh to determine afforestation effects on soil properties. At soil depths of 0-10, 10-30 and 30-40 cm across three different land strips viz. inland, middle and sea side in 12- and 17-year-old keora （Sonneratia apetala） plantations, soil moisture, particle density, organic matter and C, total N, pH, available P, K, Na, Ca and Mg were significantly （p≤0.05, p≤0.01, p≤0.001） higher, and soil salinity significantly （p〈0.001） lower than that in their adjacent barren lands. Soil moisture, particle density, organic matter and C, total N, pH, soil salinity, available P, K, Na, Ca and Mg of surface soil in Char Alim plantation at inland were 31.09%, 2.24 g.cm^-3, 2.41%, 4.14%, 0.58%, 7.07, 0.09 dS＇cm^-1, 28.06 mg.L^-1, 0.50 mg-L^- 1 11.5 mg-L^-1, 3.30 mg·L^-1 and 2.7 mmol.kg^-1, respectively. Their corresponding values for the same depth and land position at adjacent Char Rehania barren land were 16.69%, 1.25g.cm^-3, 0.43%, 0.74%, 0.25%, 6.57, 0.13 dS.cm^-1, 13.07mg-L^-1, 0.30 mg.L^-1, 1.4 mg.L^-1, 0.30 mmol·kg^-1 and 0.50 mg.L^-1, respectively. Soil moisture, particle density, organic matter and C, total N, pH, available P, K and Ca decreased, and soil salinity, available Na and Mg increased from inland towards sea side in the plantations. Although soil texture did not differ in most soil depths between plantation and adjacent barren land, proportion of sand particle was significantly （p≤0.01） lower and silt particle significantly （p〈0.001） in the plantations higher than that in their adjacent barren lands. In the study, evaluation of all the parameters was also done for the other pair of lands.

Possible effect of climate changes on the coastal zone of the Yangtze River Delta

A coastal historical evolution of the Yangtze River Delta was discussed in this paper on the basis of the historical data of the coastal zone and an estimation was made for the future change of the coast The emphasis was put on the future climate change that will have influence on the sea wall, coastal navigation and freshwater resources in the Delta It was also pointed out that the global warming and precipitation increase in the Yangtze River Valley may exert more impact on the zone In addition, some measures describing how to adapt to the climate change and reduce its impact were put forward

基于能值的海岸带生态修复成效评估——以鹦鹉洲湿地为例

鹦鹉洲湿地自建成以来已开展了连续5年以上的实地调查和监测,结合长期监测数据构建科学系统的修复成效评价体系对海岸带生态修复工程的评估具有重要的参考价值.采用能值分析方法,通过实地调研、科学监测和查阅文献,搜集所需相关数据,构建了湿地生态系统能量分析结构图和能值指标体系,对自然资产、生态服务等主要能值指标进行了分析,并比较了不同修复时期湿地的功能表现.研究结果表明:2021年,鹦鹉洲湿地自然资产总能值为8.92×1016 sej,相当于能值–货币价值22.47万元,湿地生态服务总能值为8.88×1017 sej·a^(-1);实施生态修复后,鹦鹉洲生态质量明显改善,其自然资产和生态服务能值分别是修复前的5.01倍和5.73倍;鹦鹉洲湿地生态系统的能值自给率(emergy self-support ratio,ESR)为0.47,能值产出率(emergy yield ratio,EYR)和能值可持续指数(emergy sustainable index,ESI)分别为28.29和25.03,表明湿地产出效率高且可持续发展空间较大.研究显示:基于长期监测数据,采用能值分析方法可较好地反映海岸带生态修复工程成效,所构建的评估体系及方法可为类似海岸带修复工程提供参考.

中国沿海地区制度创新对海洋经济韧性的溢出效应研究

通过“纵横向”拉开档次、核心变量法,分别测度2003—2020年中国沿海地区制度创新和海洋经济韧性,并利用空间杜宾模型分析制度创新对海洋经济韧性的溢出效应。结果表明,海洋经济韧性存在波动,各水平区在空间上均衡分布;制度创新整体呈上升趋势且存在显著空间分异;制度创新能够提升当地海洋经济韧性,但对邻近地区海洋经济韧性的正向溢出效应只有在制度创新高水平状态下才能充分展现。总体上,制度创新有利于海洋经济韧性的提升。

浅析海南岛海岸带的有效保护与合理利用

海岸带的有效保护与合理利用已经成为沿海地区可持续发展的重要途径。文章在回顾海南岛海岸带保护利用研究的基础上,梳理取得的成效和存在的问题,阐释海岸带有效保护与合理利用的重要意义;基于海岸地质和海岸动力对海岸线的控制机理,深刻剖析海南岛海岸带独特而脆弱的生态特征、人类活动影响以及丰富的旅游资源,揭示海岸动力过程和海岸带的重要性以及大气、海洋、陆地如何相互作用;提出海南岛海岸带有效保护与合理利用的新概念,构建海南岛海岸带有效保护与合理利用的顶端战略模型。为促进海南岛海岸带的有效保护与合理利用,必须以生态平衡为本,加强对海岸动力过程的调查研究,科学评估旅游地的承载能力,适时开展资源数据挖掘与监测预警,启动海南岛海洋类世界自然遗产申报及建设工作,探索以“立法先行、统筹规划、宏观调控、科学支撑、财力保障、统一管理、公众参与”为核心的“海南模式”。

考虑刚柔组合的海岸复合型植被消波特性研究

海岸植被在消减波浪能量方面发挥着重要作用,植被消波是海岸生态防护的重要形式。以广州市南沙区龙穴岛北部近岸水动力特征为基础,通过波浪水槽物理模型试验探究不同淹没度、入射波高及柔性植被宽度比条件下单一型植被(柔性、刚性)和复合型植被(刚柔组合)消浪效果。研究结果表明:当淹没度α=0.67(低于树冠形心处淹没度0.03即水深略低于树冠形心)或α>1.00(水深高于树冠顶部)时,单一型刚性植被消浪效果最优;当淹没度α增大至0.78和0.83(分别高出树冠形心处淹没度0.08和0.13)时,柔性和刚性复合型植被消浪效果更好。随着波高的增大,单一型植被与复合型植被的消浪效果均增强。柔性植被宽度比值B/B_(0)对植被消浪系数K的影响与淹没度和波高有关:当α<1.00时,消浪系数K随B/B_(0)的增大先增大后减小;当α=1.00时,消浪系数K随B/B_(0)的增大先减小后增大再减小,且均在B/B_(0)时消浪系数达最大;当α>1.00时,消浪系数K随B/B_(0)的增大呈现减小的变化趋势。研究可为当地植被生态护岸工程建设提供理论支撑。

旅游型海岸区域土地利用变化·生态效应及驱动力分析——以三亚市海棠区为例

以三亚市海棠区为例,运用ArcGIS和ENVI软件对2002—2022年遥感影像进行处理,探索20年来土地利用变化趋势;计算人均生态足迹和生态承载力,分析土地利用变化产生的生态环境效应。结果表明:海棠区的土地利用状况发生了巨大的变化,其中变化较为显著的是耕地、林地、建设用地;耕地和林地的流向主要是建设用地。这一时期海棠区高速发展,人类活动对土地利用的影响加剧。海棠区土地利用生态效应不宜乐观,海棠区生态足迹与生态承载力供给呈反方向发展趋势,海棠区人口对自然资源的利用已逐渐接近自然生态系统的生态承载力饱和范围。

滨海软土超长深基坑开挖时空效应监测分析

滨海软土基坑开挖中的空间效应和时间效应对基坑稳定性具有重要影响。为了控制软土地区基坑变形,本文以穗莞深城际铁路前海站超长深基坑工程为例,通过分析开挖过程中的围护结构水平位移、周边地表沉降、支撑内力等数据,研究超长基坑在开挖过程中的时空效应。结果表明:(1)基坑开挖中空间效应明显,基坑中部围护结构水平位移比端部大18.3%;(2)围护结构位移差异会导致坑边土体出现差异沉降现象,距离坑边相同距离时基坑纵向最大沉降差异达到17.5%;(3)施工间期,同一工况下的支护结构位移及受力均会随着时间的增长而增大;(4)软土地层中前四道混凝土内支撑养护期间,围护结构最大水平位移分别增长了31.2%,30.9%,23.2%,14.4%;(5)工程中应合理考虑基坑开挖的时空效应。

Response of Coastal Groundwater Table to Offshore Storms

Large groundwater table fluctuations were observed in a coastal aquifer during an offshore storm. The storm induced significant changes of the mean shoreline elevation, characterized by a pulse like oscillation. This pulse propagated in the aquifer, resulting in the water table fluctuations. A general analytical solution is derived to quantify this new mechanism of water table fluctuation. The solution is applied to field observations and is found to be able to predict reasonably well the observed storm induced water table fluctuations. Based on the analytical solution, the damping characteristics and phase shift of the oscillation as it propagates inland are examined.

江苏沿海波浪能资源评估研究

随着“3060”目标的提出,波浪能作为一种可持续发展的清洁能源,愈发受到重视。基于此,本文搭建江苏海域的波浪模式,以江苏沿海2021年至2023年的波浪能资源为分析对象,对江苏沿海波浪能流密度空间分布、有效波时和季节变化指数等方面开展初步研究。结果表明:江苏沿海年平均波浪能流密度介于0~11 kW/m,有效波时介于0~6000 h,长江口外深远海波浪能流密度和有效波时相对较大,海州湾内波浪能流密度和有效波时相对较小。越靠外海,波浪能流密度和有效波时越大;纬度越低,波浪能流密度和有效波时向外海增加越明显。江苏沿海区域季节变化指数集中于0.3~1.0,海州湾南侧至洋口港北侧近海区域以及长江口外深远海区域季节变化指数相对较大。该研究结果可为江苏等沿海波浪能资源的开发利用、波能电站的开发选址等方面提供参考。

A method for estimating the fresh water-salt water interface with hydraulic heads in a coastal aquifer and its application

Examining the descriptions of piezometric heads at two points in both the salt water and fresh water zones reveals that when the groundwater flow system is in steady state and satisfies the Dupuit assumption, the location of the fresh water-salt water interface in a homogeneous, isotropic, and unconfined coastal aquifer can be estimated based on a piezometric head of fresh water at a point in the fresh water zone （from the water table to the interface） vertically lined up with a piezometric head of salt water at a point in the salt water zone （from the interface down）. Research shows that the new method is a general relation and that both the Hubbert relation describing the location of the interface and the Ghy- ben--Herzberg relation are special cases of this method. The method requires two piezometric wells to be close to each other and each tapping into a different zone. Measurements of piezometric heads at a well cluster consisting of piezometric wells tapping separately into fresh water and salt water zones near Beihai, China at 5-day intervals for 15 months are used to illustrate the estimation of interface location. The depth of the interface for well H5 ranges from 32 to 72 m below the sea level.

Rural Labor Force Transfer Training Effects Evaluation by Matching Methods: Evidence from Yunnan Province of China

Rural labor force transfer training is one of important poverty alleviation measures in China. This paper describes training participation situation and evaluates training effects by matching methods in the case of coastal autonomous minority nationality areas of Yunnan province by using 2053 rural household data. The result shows that the average training participation from 2006 to 2008 is 26.39 percent. In addition, ATE is 18.33 percent, TT is 18.99 percent, TUT is 18.09 percent. And,TUT . It demonstrates that the rural labor force transfer training program is effective and well-directed in coastal autonomous minority nationality areas of Yunnan province of China.

Using Urban Landscape Trajectories to Assess Fragmentation in Mountainous Coastal Areas: A Case Study of Shenzhen, China

Rapid urbanization in mountainous coastal areas causes dramatic changes in land use and land cover(LUCC)for their geographic location.To understand changes in landscape trajectories in such regions,we examined temporal and spatial changes in urban landscapes in Shenzhen,China,a city that has undergone rapid urbanization in recent decades,and investigated the drivers of landscape pattern evolution at different scales from LUCC data from 1985,1995,2005,and 2015.The results show that the landscape of Shenzhen has changed dramatically over the 30 years from 1985 to 2015.The proportion of forest area decreased from 50.81%to 37.81%,while the proportion of construction land increased from 17.83%to 48.28%.The changes in the landscape patterns in Shenzhen were driven mainly by human activity.This study is one of the first to assess landscape dynamics of the rapid urbanization from the angle of mountainous coastal area,which plays an important role in the land use and city regulation of the global coastal mountains.

中国沿海渔港建设回顾与展望

新中国成立以来,中国沿海渔港建设取得了长足发展,从起步建设、重点提升、快速发展、系统提升和高质量发展5个阶段系统总结了中国沿海渔港的建设历程,阐述了取得的重要成效,分析了中国沿海渔港建设面临的渔港防灾减灾体系亟须完善、渔港经济区建设任重道远、渔业综合管理改革亟待加强、渔港环境治理问题日益突出等一系列新形势,从加大沿海渔港和避风锚地布局建设力度、稳步推进渔港经济区建设、加强渔港水产品交易冷链物流一体化项目的建设、促进渔港渔村一体化建设、建设绿色渔港和加快科技创新6个方面提出中国沿海渔港未来的发展重点,对于中国沿海渔港建设具有一定的参考意义。

Effects of topography on the sub-tidal circulation in the southwestern Huanghai Sea(Yellow Sea)in summer

A nested circulation model system based on the Princeton ocean model （POM） is set up to simulate the currentmeter data from a bottom-mounted Acoustic Doppler Profiler （ADP） deployed at the 30 m depth in the Lunan（South Shandong Province, China） Trough south of the Shandong Peninsula in the summer of 2008, and to study the dynamics of the circulation in the southwestern Huanghai Sea （Yellow Sea）. The model has reproduced well the observed subtidal current at the mooring site. The results of the model simulation suggest that the bottom topography has strong steering effects on the regional circulation in summer. The model simulation shows that the Subei （North Jiangsu Province, China）coastal current flows north- ward in summer, in contrast to the southeastward current in the center of the Lunan Trough measured by the moored currentmeter. The analyses of the model results suggest that the southeastward current at the mooring site in the Lunan Trough is forced by the westward wind-driven current along the Lunan coast, which meets the northward Subei coastal current at the head of the Haizhou Bay to flow along an offshore path in the southeastward direction in the Lunan Trough. Analysis suggests that the Subei coastal current, the Lunan coastal current, and the circulation in the Lunan Trough are independent current systems con- trolled by different dynamics. Therefore, the current measurements in the Lunan Trough cannot be used to represent the Subei coastal current in general.

江苏沿海地区“三生”功能空间演化及生态效应

江苏沿海地区正在承受高质量发展和资源约束的双重压力,综合测算生态系统服务价值和生态环境质量指数,分析“三生”功能空间演化的生态效应,能够为空间优化提供参考。结果表明:(1)2000-2020年,江苏沿海地区生产空间减少1921.41 km^(2),生活空间和生态空间分别增加1468.60 km^(2)和452.81 km^(2)。(2)2000-2020年,连云港、盐城两市的生态系统服务价值分别增加1.02×10^(9)元和4.33×10^(9)元,南通市减少1.39×10^(9)元,同期3市的生态环境质量指数变化值分别为0.0088、0.0061和-0.0113。(3)2000-2020年,连云港和盐城“三生”功能空间转移的生态正效应大于负效应,南通则相反。生产空间转为生态空间是生态环境改善的驱动因素,生产空间转为生活空间是生态环境恶化的主要原因。江苏沿海地区在后续规划中应根据生态效应的驱动因素,适当调整“三生”功能空间,推动该地区高质量发展。

大沽河流域滨海湿地景观格局变化及其驱动机制

以大沽河流域滨海湿地为研究区域,以2000、2010及2019年的Landsat 5 TM和Landsat 8 OLI遥感数据为数据源,提取大沽河流域滨海湿地信息,采用训练分析法和景观格局指数的时空分异规律,分析不同时期人类活动对滨海湿地景观格局变化的影响。结果表明,2000-2019年间湿地、水体总面积变化较小,自然湿地景观面积整体呈现逐年增加的趋势,而人工湿地景观面积整体呈现逐年减小的趋势。大沽河河道在近20年间总体河流面积增加,河道变宽,大沽河流域滨海湿地总面积整体变化较小,其中,自然湿地景观中除滩涂湿地景观面积逐年减小外,湖泊、浅海水域、季节性河流和永久性河流湿地景观面积均增大。大沽河流域滨海湿地的斑块密度指数和斑块破碎化指数均呈现出先增后降的趋势。围垦、人口增长、城镇化发展、污染、海水入侵和环保举措等人为因素是引起大沽河流域滨海湿地面积和景观格局变化的主要驱动因素。