Drivers,Trends,and Patterns of Changing Vegetation-greenness in Nansha Islands,China from 2016 to 2022

Changes in vegetation status generally also represents changes in the ecological health of islands and reefs(IRs).However,studies are limited of drivers and trends of vegetation change of Nansha Islands,China and how they relate to climate change and human activities.To resolve this limitation,we studied changes to the Normalized Difference Vegetation Index(NDVI)vegetation-greenness index for 22 IRs of Nansha Islands during normal and extreme conditions.Trends of vegetation greenness were analyzed using Sen's slope and Mann-Kendall test at two spatial scales(pixel and island),and driving factor analyses were performed by time-lagged partial correlation analyses.These were related to impacts from human activities and climatic factors under normal(temperature,precipitation,radiation,and Normalized Difference Built-up Index(NDBI))and extreme conditions(wind speed and latitude of IRs)from 2016 to 2022.Results showed:1)among the 22 IRs,NDVI increased/decreased significantly in 15/4 IRs,respectively.Huayang Reef had the highest NDVI change-rate(0.48%/mon),and Zhongye Island had the lowest(–0.29%/mon).Local spatial patterns were in one of two forms:dotted-form,and degradation in banded-form.2)Under normal conditions,human activities(characterized by NDBI)had higher impacts on vegetation-greenness than other factors.3)Under extreme conditions,wind speed(R^(2)=0.2337,P<0.05)and latitude(R^(2)=0.2769,P<0.05)provided limited explanation for changes from typhoon events.Our results provide scientific support for the sustainable development of Nansha Islands and the United Nations‘Ocean Decade’initiative.

Gravity modelling of crustal architecture and heterogeneity in the Nansha Block,South China Sea

The stretched structure and heterogeneity of the crust of the Nansha Block,the southern continental margin of the South China Sea(SCS),are not well understood.We used published ocean bottom seismic(OBS)/multichannel reflection seismic(MCS)profiles across the Nansha Block to establish five two-dimensional crustal structure models.Using gravity modelling with magnetic anomaly inversion,we obtained the distribution of density and local magnetic susceptibility of the crust.The models show that the distribution of density and thickness of the upper crust in the Nansha Block is uneven,and the thick upper crust is prevalent in the regions close to the continent-ocean transition(COT)showing different characteristics.The interpreted Mesozoic granite blocks and Precambrian rigid basement reflects the heterogeneity in the material composition of the SCS continental margin.Based on the thinning styles of different crustal layers,we suggest that the Nansha Block has a three-layer thinning pattern.The uppermost pre-rift layer was deformed via brittle fractures,the upper crust was sheared by discrete shear zones,and the lower crust experienced ductile deformation.The inherited pre-rift thermal regime,mechanical state,and material composition of the SCS continental margin affected the extensional structure of the crust.

Considering Regional Connectivity and Policy Factors in the Simulation of Land Use Change in New Areas:A Case Study of Nansha New District,China

Numerous emerging development areas worldwide are receiving attention;however,current research on land use change simulation primarily concentrates on cities,urban clusters,or larger scales.Moreover,there is a limited focus on understanding the impact of regional connectivity with surrounding cities and policy factors on land use change in these new areas.In this context,the present study utilizes a cellular automata(CA)model to investigate land use changes in the case of Nansha New District in Guangzhou,China.Three scenarios are examined,emphasizing conventional locational factors,policy considerations,and the influence of regional connectivity with surrounding cities.The results reveal several key findings:(1)Between 2015 and 2021,Nansha New District experienced significant land use changes,with the most notable shifts observed in cultivated land,water area,and construction land.(2)The comprehensive scenario exhibited the highest simulation accuracy,indicating that Nansha New District,as an emerging area,is notably influenced by policy factors and regional connectivity with surrounding cities.(3)Predictions for land use changes in Nansha by 2030,based on the scenario with the highest level of simulation accuracy,suggest an increase in the proportion of cultivated and forest land areas,alongside a decrease in the proportion of construction land and water area.This study contributes valuable insights to relevant studies and policymakers alike.

未来海上城市设计构想

基于粤港澳大湾区的发展战略和未来城市发展空间模式,将“未来”“海洋”与“城市”三者紧密结合进行研究设计,为未来城市向海洋拓展提供灵感与导向是未雨绸缪之举。2023“未来海上城市”研究生国际联合工作坊以广州南沙龙穴岛海域设计构想为题具有重要价值和意义。重庆大学设计小组方案融入海洋科创、海上人居、海上田园、海洋能源、海洋交通、海洋生态等要素,聚合科学与技术手段,从不同视角梳理总结未来海上城市发展模式和建设路径的可能性,是对未来海上城市建设模式和发展远景的探索与尝试。

城镇密集区公路桥群绿色建造创新探索

为提升城镇密集区公路绿色建造水平,结合南(沙)—中(山)高速的项目特点及工程需求,将绿色发展理念贯彻到公路设计、施工、运营、养护和管理的全寿命周期,重点研发了公路桥群工业化智能建造、公路资源综合利用、滨海湿地区公路环境保护与粤港澳大湾区交旅融合设计等四类十项创新技术。其中,预制梁环形生产线、非标准八车道等为项目特色首创技术,初步构建了典型城市群绿色桥群公路技术体系,并对未来重点发展方向进行了展望,以期丰富和完善粤港澳大湾区绿色公路技术体系,为其他高度城镇化区域可持续发展提供参考。

Physical and Mechanical Properties of Coral Sand in the Nansha Islands

Coral sand is a unique material developed in the tropical ocean environment, which is mainly composed of coral and other marine organism debris, with the CaCO3 content up to 96 %. It has special physical and mechanical properties due to its composition, structure and sedimentary environment. In this contribution, we discuss its specific gravity, porosity ratio compressibility, crushing, shearing and intensity for coral sand samples from the Nansha islands based on laboratory mechanical tests. Our results show distinct high porosity ratio, high friction angle and low intensity as compared with the quartz sand. We believe that grain crushing is the main factor that influences the deformation and strength of coral sand. Comprehensive study on the physical and mechanical properties of coral sands is significant in providing reliable scientific parameters to construction on coral islet, and thus avoids accidents in construction.

南沙珊瑚礁潟湖坡微地貌对沉积物粒度特征的影响

潟湖坡是礁坪沉积物向潟湖盆搬运的关键地貌带,对了解礁后沉积过程和环礁发育演化至关重要。然而,潟湖坡微地貌特征及其对沉积物粒度的影响还未明确。文章对南沙群岛主权礁与三角礁潟湖坡开展研究,采集表层沉积物并结合水深数据和水下微地貌开展粒度分析,结果表明:1)主权礁与三角礁潟湖表层沉积物以砂级颗粒为主,粉砂与细砾质量分数较少,其中主权礁沉积物中砂级颗粒质量分数为94.55%,细砾为4.18%,粉砂为0.61%;三角礁S1-S1′方位含砂93.96%,细砾4.04%,粉砂1.65%;S2-S2′方位含砂91.73%,细砾为6.84%,粉砂为1.17%。潟湖砂体的中值粒径与水深呈显著负相关,粒度分布曲线在深水区呈单峰式,在浅水区呈双峰式,整体偏态为负偏态。2)物源和水动力特征是影响南沙珊瑚礁潟湖坡砂体粒度分布的主要因素,主权礁潟湖坡点礁密布,周围颗粒粒径显著增大,削弱了水深与粒度的负相关性,表明潟湖点礁亦是重要物源;三角礁潟湖坡发育海草床,减弱了颗粒的动力再分选作用,形成粗粒和细粒混积的双峰形态。3)潟湖坡微地貌对颗粒粒度分布起关键作用。主权礁双峰式分布曲线的形成主要受潟湖点礁的影响,而海草根系的固沙作用减弱了颗粒的动力分选作用,形成三角礁双峰式分布曲线。

广州南沙国际金融论坛永久会址主体结构设计

广州南沙国际金融论坛永久会址属于大型复杂会议类建筑,具有大底盘双塔、钢屋盖连体、大开洞、竖向质心偏移、大跨结构等多项不规则项。介绍了结构重力体系和抗侧体系的选型思路,主体结构选用混凝土框架+屈曲约束支撑体系,外表皮采用空间钢结构。重点分析了单塔与整体结构的差异以及钢屋盖对下部双塔的影响。通过弹塑性分析,对大震作用下各个时程点的损伤水平进行评估,对大开洞的楼板进行了地震及温度作用下的楼板应力分析;对大跨桁架进行了抗连续倒塌分析。结果表明结构可满足大震不倒的要求,支撑承载力能充分发挥,大底盘结构具有良好的基座支撑特性。

Analysis on Ecological Benefits of Urban Wetlands and Protection Measures with a Case of Nansha Wetland

Nansha wetland plays a crucial role in ecological balance of the Pearl River Delta or even Guangzhou. The research, based on researches available, analyzed ecological benefits of Nansha wetland and proposed protection measures in order to better protect urban wetlands and achieve sustainable development of ecological resources of Nansha wetland.

伴随式服务导向下地块公共空间设计管控研究——以广州南沙明珠湾起步区为例

在城市设计视角下,良性的公共空间设计管控包括获得理想的设计方案以及有序的实施过程。以地块公共空间及其设计管控为研究对象,辨析“地块公共空间”的概念与属性,推演设计管控及全流程伴随式服务需求,提出伴随式服务导向的地块公共空间设计管控策略,即在规划设计阶段,以精细化技术提升设计管控的科学性;在建设实施阶段,以规范化制度提高设计管控的实效性;在运维管理阶段,以多主体治理优化设计管控的长效性。同时,结合广州南沙明珠湾起步区滨水绿地、口袋公园的设计管控实践,验证了刚性管控与弹性引导的技术体系。

关于在南沙群岛海域设立“南海牧场”的建议

该文提出在南海海域设立海洋牧场的设想。文章分析了南海牧场设立的战略意义:一是贯彻落实中央一号文件建设海洋强国的重大战略部署;二是巩固我国在南海重要海域的主权;三是利用海洋资源促进经济发展。同时,文章也讨论了中国南海牧场可开展的养殖业务,如鱼类养殖、贝类养殖等,以及保障其顺利运行的有关措施。该文认为,在南海建设海洋牧场将有利于我国海洋强国的建设及南海主权的维护。此外,通过与周边地区合作开发,也有利于缓解南海紧张局势。

Magmatic-tectonic response of the South China Craton to the Paleo-Pacific subduction during the Triassic:a new viewpoint based on Well NK-1

The Nansha Block(NB)is one of the blocks separated from the southern margin of the South China Craton(SCC)by the western Pacific subduction,which contains rich information of geodynamic and tectonic transformation.To reveal the essence of western Paleo-Pacific subduction during the Triassic period,Well NK-1 in this block was selected for petrographic study,and published research data from other cooperative teams were compared.A double-cycle pattern of basic to neutral magmatic volcanism was established,and 36 lithological rhythmic layers and representative cryptoexplosive breccia facies and welded tuff bands were identified.Combined with a reanalysis of published geochronological data,geochemical elements,and isotope geochemistry,we found that the rock assemblages could be divided into an intermediate-acid dacite(DA)series(SiO_(2)>65%)and basaltic(BA)series(Co<40μg/g),which was formed during the early Late Triassic((218.6±3.2)–(217.9±3.5)Ma).BA exhibits obvious calc-alkaline island-arc magmatic properties:(^(87)Sr/^(86)Sr)_i ratio ranging 0.70377–0.71118(average:0.70645),^(147)Sm/^(144)Nd ratio ranging 0.119–0.193(average:0.168),and chondrite-normalized rare earth element(REE)curves being flat,while DA exhibits remarkable characteristics of subducted island-arc andesitic magma:(^(87)Sr/^(86)Sr)_i ratio(0.70939–0.71129;average:0.71035),εNd(t)value(-6.2–-4.8;average:-5.6)andε_(Hf)(t)value(-2.9–-1.7,average:-2.2)show obvious crust-mantle mixing characteristics.BA and DA reveal typical characteristics of island-arc magma systems and typeⅡenriched mantle(EM-Ⅱ)magma.BA magma was likely resulted from the process whereby the continental crust frontal accretionary wedge was driven by the Paleo-Pacific slab subduction into the deep and began to melt,resulting in a large amount of melt(fluid)joined the asthenosphere on the side of the continental margin.In contrast,DA magma was likely resulted from the process whereby the plate front was forced to bend with increasing subduction distance,which triggered the upwelling of the asthenosphere near the continent and subsequently led to the partial melting of the lithospheric mantle and lower crust due to continuous underplating.The lithospheric thinning environment in the study area at the end of Triassic created suitable conditions for the separation between the NB and SCC,which provided an opportunity for the formation of the early intracontinental rift during the later expansion of the South China Sea(SCS).

广州港南沙港区深厚层软土原位测试方法

广州南沙港区作为广州市重点发展的深水港,其港区内广泛分布深厚软土层,局部软土深度超过30 m。港区内软土层特征主要受两次大规模海侵、海退及珠江水系的影响。上层软土主要由淤泥组成,厚度约10~20 m,夹粉细砂薄层或条带状砂层;下层软土主要由淤泥质土组成,含有机质及腐木碎,厚度约4~8 m。软土参数是影响南沙港区工程建设的重要指标,采用原位测试不易受到影响,可准确呈现软土的力学性质。通过对比分析各种常用的原位测试方法,提出适用于南沙港区深厚软土层的原位测试方法。在工程实践中分别采用不同的原位测试方法获取工程参数,尤其采用不同规格的十字板板头进行十字板剪切试验,旨在为区域内同类软土勘察、设计及施工提供参考。

1947年澳大利亚筹备对日和约时南沙群岛的档案搜集与立场

1947年初澳大利亚为维护国家利益提议尽早缔结对日和约,并组建太平洋和约筹备委员会具体负责拟定对日和约草案。在对日领土处置时为了厘清战时为日所占之南沙群岛的归属情况,澳大利亚初步搜集了1939~1946年有关南沙群岛“争议”各方主张、日本占领南沙时的声明与英法反应、战时日本对南沙的开发利用和战后中国政府收复南沙群岛史实等6份核心档案,在此基础上,综合研判后形成南沙群岛归属上中国已实控、法方态度不明及其军事战略价值有限的认知。为此1947年7月9日筹备委员会拟定的对日和约草案只规定了日本放弃南沙群岛,未写明其归属。不过,7月15日澳大利亚驻南京公使馆发给澳外交部的第341号函电旗帜鲜明地指出,除却中国对南沙群岛提出最早主张外,因为岛上居民主要是中国渔民这一事实,别无任何可靠的权威依据,同时排除了法国对南沙群岛提出“主权诉求”的可能。尽管澳大利亚的上述立场最终未写入新一轮的对日和约草案,但其内部函电字里行间流露出的对中国拥有南沙群岛主权的认可,无疑是不可否认的。

中国知识精英对日本侵占南沙的因应——以民国报刊为中心的考察

1939年3月底,日本侵占南沙群岛是抗日战争进入相持阶段后日本在“南进政策”上迈出的重大一步。当时国内知识精英通过报刊密集发表社论和文章,提出我国对日本侵占南沙的因应之策:坚持南沙群岛主权属我;厘定斯巴特莱群岛为我团沙群岛;研判日本侵占南沙是剑指法、英、美、荷南洋殖民地而与对华战事无涉。这不仅提升了抗战相持阶段后国人进一步的抗日爱国热情、加快了反法西斯统一战线的形成,还为抗战胜利后中国政府正式收复南海诸岛、更改“团沙群岛”为“南沙群岛”和绘制《南海诸岛位置图》等一系列有效管辖南海诸岛的行动,奠定了强大的舆论和思想基础。

超大型集装箱船舶顺流靠泊南沙港风险控制与应急操作

相对传统的顶流靠泊,超大型集装箱船舶顺流靠泊操作难度大、风险系数较高。操作中如果发生主机倒车不出的突发状况,应对化解险情更加困难,一旦操作不当,势必对码头设施及靠泊船造成严重后果和影响。通过分析实际案例,结合超大型集装箱船舶操纵特点和南沙港实际情况展开分析,以及引航员间广泛交流探讨解决方案,给出了顺流靠泊中操作关键点的风险防控指标及倒车不出的应急操作预案,以保证靠泊安全,同时发挥顺流靠泊技术的优势。

20世纪70年代中国香港报刊对西沙事态的反应——以《明报月刊》为考察中心

1974年1月,西沙海战爆发后,中国香港报刊积极报道与战事相关的内容,对中国香港社会的维权动态以及南海诸岛史地知识亦多有着墨,但很少深入探讨中国南海主权。相对而言,《明报月刊》则刊登了一系列由中国香港、中国台湾学者和海外华人学者所撰写的学术维权文章,为中国南海诸岛主权的论证提供了历史和法理依据。

克洛玛非法“探险”南沙与中国台湾、菲律宾马尼拉交涉

1956年3月到5月,菲律宾克洛玛等人非法“探险”南沙群岛,引发了台湾地区当局和菲律宾围绕南沙归属问题的交涉。台湾地区当局在交涉之初所具有的优势地位,因海军即将巡弋南沙得到加强,然而受冷战思维的影响,它一开始就采取了妥协态度,这也预示着交涉的最终结果。另外,国内外媒体尤其是中国香港报纸对该事件的报道,在一定程度上有助于还原当时交涉的若干场景。

越南建构的南海历史地名叙事及其存在的逻辑问题

在中越之间关于南海的争议中,越南方面找到诸多历史资料来支撑其主张。这些史料中的地名繁杂而混乱,但却被罗织成相互关联的地名关系。这种历史叙述看似系统而完整,但其各个节点却缺乏充分的证据和合理的逻辑。以越南发行的白皮书为线索,可以找到越南建构南海历史叙述的主要依据。详细考察这些越南和西方文献中相关地名之间的关系,即可进一步发现越南南海主张中的历史地名叙事逻辑及其问题所在。

20世纪上半叶日本在南沙群岛扩张的历史考察

20世纪上半叶,日本在对外扩张过程中密切关注中国南沙群岛,并将实现对其的控制和占领作为主要目的。日本政府对南沙群岛进行了多次非法调查,编造依据,企图“合法”侵占中国南沙群岛。日本不仅掠夺南沙群岛资源,而且在太平岛建设军事设施,为进军东南亚做准备。日本谋划、侵占中国南沙群岛是其推南进政策的重要一环。在此过程中,日本关注的重点是南沙群岛的战略地位,而非经济资源。日本的侵占导致南沙群岛成为二战后国际社会需要处理的问题之一。