3D numerical model for Pearl River estuary

A 3D numerical model with an orthogonal curvilinear coordinate in the horizontal direction and sigma coordinate in the vertical direction has been developed. This model is based on POM (Princeton Ocean Model). In this model a second moment turbulence closure submodel is embedded and the stratification caused by salinity and temperature is considered. Furthermore, to adapt to estuary locations where the flow pattern is complex, the horizontal time differencing is implicit with the use of a time-splitting method instead of the explicit method in POM. This model is applied to the Pearl River estuary, which is the largest river system in South China, with Hong Kong at the eastern side of its entrance. The computation is verified and calibrated with field measurement data. The computed results mimic the field data well

模拟“微型生物碳泵”对南海储碳的贡献

海洋中最重要的两种生物储碳机制,包括生物泵和微型生物碳泵,其中后者在中国海中的定量估算和模拟的相关研究还未见报道.文章以南海为研究区域,构建了一个包含MCP过程的物理-生态系统耦合海洋模型.模型结果显示,南海整体平均的MCP储碳率为1.55mg C m-2d-1;如果取1000m深的颗粒物输出通量作为BP的估计,模型估算的MCP:BP比例约为1:6.08.在此基础上,用该模型预测未来南海海表增温2个典型场景下南海生态系统,特别是MCP和BP储碳过程的响应.模拟结果表明,增强的海表层化会造成输入表层的营养盐减少,进而导致硅藻生物量和生产力的降低,最终抑制BP的储碳率.然而,在这些场景下,由于超微型浮游生物的生产力增加,反而有利于细菌活动,部分补偿生产力的降低,造成MCP对于全球变暖的响应具有非线性的特征.总体而言, MCP:BP比例在两个场景下都有所增加,特别是在4℃增暖的场景下增加至1:5.95,表明在全球变暖的大背景下,未来海洋中MCP碳储的重要性将更加突出.国家重点基础研究发展计划项目(编号:2013CB955704);;国家海洋局全球变化与海气相互作用专项项目(编号:GASI-03-01-02-05、GASI-IPOVAI-01-04);;国家自然科学基金项目(批准号:41630963、41476007和41476005)资

A case study of cumulative effects assessment for harbor planning in China

累积影响评价是战略环境评价的主要方法和重要内容之一,但目前还缺乏通用的评价程序和方法。通过识别港口规划的累积影响源和途径,建立了基于水动力数值模型的累积影响评价的量化评估和分析框架。以厦门港嵩屿港区规划为例,通过对海湾纳潮量及各敏感点流速的模拟,计算淤积量及其分布变化,进而推测海域水质和底质变化,并分析了由此引起的海洋生物群落的变化趋势。通过比较不同岸线方案的累积影响,为港区岸线优选提供了科学判据。实践表明,该方法框架综合运用定量预测和定性分析手段,其结果能为港口规划的战略环境评价提供科学依据。 【英文摘要】 Cumulative effects assessment (CES) has become an important approach and also a key component of the strategic environmental assessment due to the increased recognition that most significant environmental changes are results of combined effects of many individual impact factors. Analyzing combined environmental effects is simple in principle but difficult in practice due to a lack of simple and effective CES methods and procedures. The paper presents a case of CIE for the harbor planning project for Songyu ..

The coastal ocean response to the global warming acceleration and hiatus

本研究揭示了全球沿岸对目前全球气候变暖减缓背景下的不同的区域响应，有助于理解全球增暖减缓现象的潜在机理，并为近期发生在各个海岸地区的极端热和极端冷的事件提供了更好的理解，有助于灾害防治和生态保护的政策制定。【Astract】Coastlines are fundamental to humans for habitation, commerce, and natural resources. Many coastal ecosystem disasters, caused by extreme sea surface temperature (SST), were reported when the global climate shifted from global warming to global surface warming hiatus after 1998. The task of understanding the coastal SST variations within the global context is an urgent matter. Our study on the global coastal SST from 1982 to 2013 revealed a significant cooling trend in the low and mid latitudes (31.4% of the global coastlines) after 1998, while 17.9% of the global coastlines changed from a cooling trend to a warming trend concurrently. The trend reversals in the Northern Pacific and Atlantic coincided with the phase shift of Pacific Decadal Oscillation and North Atlantic Oscillation, respectively. These coastal SST changes are larger than the changes of the global mean and open ocean, resulting in a fast increase of extremely hot/cold days, and thus extremely hot/cold events. Meanwhile, a continuous increase of SST was detected for a considerable portion of coastlines (46.7%) with a strengthened warming along the coastlines in the high northern latitudes. This suggests the warming still continued and strengthened in some regions after 1998, but with a weaker pattern in the low and mid latitudes.该研究工作获得了中国国家自然基金委、福建省和美国NOAA-Sea Grant 的资助

Modeling the total allowable area for coastal reclamation: a case study of Xiamen, China

填海造地在解决海岸带地区发展空间短缺问题的同时,严重损害了人类赖以生存和发展的海洋与海岸带生态系统。如何控制大规模填海造地是我国面临的重大课题。构建了估算海湾最大可允许填海造地面积的分析框架和模型。填海造地的各种收益和成本,包括环境和生态成本被系统性地量化并嵌入到框架和模型之中。模型的估算结果可以为实施控制填海造地的约束机制提供科技支撑。利用建立的框架和模型对厦门西海域模拟的结果显示:当贴现率为4.5%时,厦门西海域最大可允许填海面积是89.44 HM2,其面积至少应该保持在44.52 kM2;即便是使用8%的高贴现率,最大可允许填海面积也只占规划填海面积的35.83%;如果采用更加重视环境与生态效益的低贴现率2%,则厦门西海域最大可允许填海面积是0。While creating useful space for agriculture,industry,and urban development,coastal reclamation damages considerably the marine ecosystems which human-kind depends on.How to control the large-scale coastal reclamation is a great challenge in China.This paper presents an analytical framework and model to estimate the Total Allowable Area for Coastal Reclamation( TAACR) to provide scientific support for the implementation of a coastal reclamation restriction mechanism.Various benefits and costs,including the ecological and environmental costs of coastal reclamation,are systematically quantified in the framework.Model simulations are developed using data from West Sea of Xiamen.The results show that the TAACR in West Sea is 89.44 hm2at a discount rate of 4.5%.Area of West Sea must be maintained at a minimum of 44.52 km2so that the social well-being can be maximized.Under low discount rate,2%,the TAACR is zero.Even with high discount rate,8%,the optimal reclamation area is 157.97 hm2,about 35.83% of the total planned area.国家海洋公益资助项目(201105006); 国家社会科学基金资助项目(12BJ064); 福建省自然科学基金资助项目(No.2010J01360

Evaluation of losses in bay environmental capacity based on numerical simulation—a case study of sea reclamation in Tong’an Bay, Xiamen

[摘要]：基于海湾环境容量价值影响因素的分析,采用环境经济学的影子工程法,结合水动力数值模型及其与污染物扩散的耦合模型,建立了 围填海导致的海湾环境容量价值损失的预测评估模型和方法,并以厦门同安湾为例,对同安湾4 个围填海规划方案可能造成的环境容量价 值的损失进行了预测评估.结果表明,方案1~方案4 围填海面积依次为1.98,7.73,9.38,19.24km2,围填海造成的环境容量的损失依次为 12281.3,48418.6,60706.6,132800.1 万元/a,单位面积的损失依次为62.03,62.64,64.72,69.02 元/(m2⋅a).围填海活动带来的环境成本不容忽视.基 于评估结果,针对厦门围填海的现状提出了相关的政策建议.[Abstract]:Based on an analysis of factors affecting the value of bay environmental capacity, a model evaluating the lost value of bay environmental capacity caused by sea reclamation was established using Shadow Project Method in environmental economics combined with hydrodynamic numerical model and hydrodynamic force-contaminant diffusion coupling model. The evaluation model was then applied to a case study of four planned sea reclamation projects in Tong’an Bay, Xiamen. The lost value of environmental capacity caused by projects 1 to 4 would be 1.23×108, 4.84×108, 6.07×108, 1.33×109 Yuan/a, respectively; and the lost value per unit area would be 62.03, 62.64, 64.72, 69.02 Yuan /(m2⋅a), respectively. These environmental costs should be carefully examined in relevant project evaluations. Policy recommendations were presented according to the study results and current status of sea reclamation in Xiamen.国家自然科学基金资助项目(70771098

Three-dimensional structure of a low salinity tongue in the southern Taiwan Strait observed in the summer of 2005

Cruise observations with CTD (conductivity-temperature-depth) profiler were carried out in the southern Taiwan Strait in the summer of 2005. Using the cruise data, two-dimensional maps of salinity and temperature distributions at depths of 5, 10, 15, 20, and 30 m were generated. The maps show a low salinity tongue sandwiched by low temperature and high salinity waters on the shallow water side and high temperature and high salinity waters on the deep water side. The further analysis indicates that the low salinity water has a nature of river-diluted water. A possible source of the diluted water is the Zhujiang (Pearl) Estuary. Meanwhile, the summer monsoon is judged as a possible driving force for this northeastward jet-like Current. The coastal upwelling and the South China Sea Warm Current confine the low salinity water to flow along the central line of the strait. Previous investigations and a numerical model are used to verify that the upstream of the low salinity current is the Zhujiang Estuary. Thus, the low salinity tongue is produced by four major elements: Zhujinag Estuary diluted water, monsoon wind driving, coastal upwelling and South China Sea Warm Current modifications.National Natural Science Foundation of China [40331004, 40576015, 40810069004, 40821063]; MEL Open Project [MEL0506]; ONR [N00014-05-1-0328, N00014-05-1-0606]; NSF [071003-9222

Three-dimensional pollutant transport model for the Pearl River Estuary

In this paper, the development and implementation of a three-dimensional, numerical pollutant transport model, which is based on an orthogonal curvilinear coordinate system in the horizontal direction and a sigma coordinate system in the vertical direction, is delineated. An efficient as well as simple open boundary condition is employed for pollutant transport in this mathematical model. It is then applied to model the distribution and transport of Chemical Oxygen Demand in the Pearl River Estuary. The results from the numerical simulations illustrate that the transboundary or inter-boundary effects of pollutants, between the Guangdong Province and the Hong Kong Special Administrative Region due to the wastewater discharged from the Pearl River Delta Region, are quite strong. (C) 2002 Elsevier Science Ltd. All rights reserved

Simulation of transboundary pollutant transport action in the Pearl River delta

The rapid economic development in The Pearl River delta region (PRDR) has exerted serious potential pollution threats to areas in the vicinity,,which have complicated the task of environmental protection in Hong Kong and Macau. In this paper, a three-dimensional numerical pollutant transport model coupled with a synchronised numerical hydrodynamic model, is developed and employed to simulate the unsteady transport of a representative water quality variable chemical oxygen demand in The Pearl River Estuary. It is demonstrated that there exists a transboundary pollutant transport action between Guangdong Province and Hong Kong for the pollutants in the wastewater discharged from PRDR. (C) 2003 Elsevier Ltd. All rights reserved

Numerical Simulation on Hypoxia Phenomenon at the Bottom of Pearl River Estuary During Summertime

底层水体缺氧现象已经引起了人们的广泛关注.水体底层缺氧易造成水生生物的死亡,影响了水体的生态环境,造成水质严重下降,因此找出造成水体缺氧的原因有着非常重要的意义.通过一个三维的水动力生态模型模拟并研究了夏季珠江口底层的缺氧现象.分析结果表明,盐度锋面对珠江口水体表底层氧气交换的抑制作用及底层有机耗氧物质对溶解氧的大量消耗是造成底层缺氧现象的主要原因,但潮汐所导致的强混合可以破坏这种缺氧机制的形成;底层缺氧主要与河流输送的耗氧物质有关;作为主要营养盐参与生态系统循环的磷对底层溶解氧无明显影响.Hypoxia phenomenon at the bottom of waters has aroused wide attention since early times.It can severely affect the ecosystem balance of the water,resulting in the declination of water quality by easily leading to the death of aquatic life.Therefore,finding out the reasons of water hypoxia has important significance.In this study,a three-dimensional ecological model was used to study the hypoxia phenomenon in the Pearl River Estuary during summer.Its hydrodynamic model was based on ROMS(regional ocean modeling system) and ecological model was based on the FENNEL ecological module.The results show that the dominating reasons leading to this phenomenon are the salt-front and the oxygen-consumption materials at the bottom of the water.The former restrains the exchange of oxygen that being rich in the surface water and poor in the bottom water in the Pearl River Estuary.However,strong tidal processes can weaken and ruin the hypoxia formation by enhancing the vertical mixing.Hypoxia has a close relationship with oxygen-consumption organic materials from the rivers.Being shown from the simulation result,as one of the main nutrients that engages in the circulation of the ecosystem,phosphate doesn't have obvious impact on bottom oxygen concentration