Development and Future of South China Sea Issue

Since 2010,the South China Sea issue has gone through complicated developments.The yearslong relative stability of the South China Sea has been broken by the advancement of US AsiaPacific rebalance strategy.Due to the

A comparison analysis between developed and undeveloped depressions over the South China Sea

-- In this paper, by using two sets of composite data of developed and undeveloped depressions over the South China Sea, we analyze and compare the dynamic structures, the heating fields and the vorticity budget residuals of two different types of depressions. Our conclusions are as follows:The two types of depressions are similar in thermodynamical and dynamical structures. The main differ ences are : in the high layer of developed depression there is a divergence field, with a center near the zero line of vertical wind shear, and over undeveloped depression, the divergence field is weaker and the vertical wind at its center is greater than 5 m s-1. The thermodynamical field of the former is asymmetrical and that of the latter is quasi - symmetrical. As far as the dynamics structure is concerned, the convergence in the lower layer and the difference of divergence between the upper and lower layers of developed depression is three tmies larger than that of undeveloped depression. The upward motion and heating field at the center of developed depression is also stronger than that of undeveloped one.The vorticity budget of the two types of depressions is mainly determined by the divergence term, the vorticity advection term and the vertical transport term. The residual term is also important.The principal contribution comes from the divergence term . This is more significant for developed depression than for undeveloped depression.

Research progress and challenges of natural gas hydrate resource evaluation in the South China Sea

As an efficient clean energy,natural gas hydrate(NGH)has become a hot topic in recent researches.Since1990 s,China has made great achievements and progress in NGH exploration in the South China Sea(SCS),including determination of the favorable distribution areas and favorable strata thickness,identification of the dual source for accumulation,evaluation of the prospective gas contents,verification of the widespread existence,and confirmation of the technical recoverability of NGH resources.However,there are three major challenges in the NGH studies.First,all the 24 national key and major projects in the SCS focused on trial production engineering and geological engineering in the past 20 years,while 8 of the 10 international NGH research projects focused on resource potential.Second,resource evaluation methods are outdated and some parameter selection are subjective.Third,the existing resource evaluation results are low-level with a great uncertainty,and cannot be used to guide NGH exploration and production or strategic research.To improve the evaluation of NGH resources in the SCS,future researches should focus on four aspects:(1)improve the research on the criterion of the objective existence of NGH and the method of prediction and evaluation;(2)apply new theories and methods from the global NGH research;(3)boost the research on the difference and correlation of the conditions of hydrocarbon migration and accumulation in different basins;(4)innovate the theory and method of NGH resource potential evaluation.

Deep structural research of the South China Sea: Progresses and directions

The South China Sea(SCS)is the hotspot of geological scientific research and nature resource exploration and development due to the potential for enormous hydrocarbon resource development and a complex formation and evolution process.The SCS has experienced complex geological processes including continental lithospheric breakup,seafloor spreading and oceanic crust subduction,which leads debates for decades.However,there are still no clear answers regarding to the following aspects:the crustal and Moho structure,the structure of the continent-ocean transition zone,the formation and evolution process and geodynamic mechanism,and deep processes and their coupling relationships with the petroliferous basins in the SCS.Under the guidance of the“Deep-Earth”science and technology innovation strategy of the Ministry of Natural Resources,deep structural and comprehensive geological research are carried out in the SCS.Geophysical investigations such as long array-large volume deep reflection seismic,gravity,magnetism and ocean bottom seismometer are carried out.The authors proposed that joint gravitymagnetic-seismic inversion should be used to obtain deep crustal information in the SCS and construct high resolution deep structural sections in different regions of the SCS.This paper systematically interpreted the formation and evolution of the SCS and explored the coupling relationship between deep structure and evolution of Mesozoic-Cenozoic basins in the SCS.It is of great significance for promoting the geosystem scientific research and resource exploration of the SCS.

Research on Integrated Planning Method of Offshore Oil and Gas Exploration and Development

Under the requirement of high-quality development, the research method of integrated model planning for offshore oil and gas exploration and development suitable for the western South China Sea is put forward. Based on the new round of resource evaluation and exploration and development research in the western South China Sea, the in-depth research on underground oil and gas resources, surface development facilities, external factors and economic indexes are carried out to clarify the industrial layout of oil and gas development. The potential and prospect of oil and gas exploration and development were implemented, and the main external factors and corresponding measures affecting the planning were clarified in this paper. The economic evaluation model suitable for the region is established based on the analysis of internal rate of return, comprehensive barrel oil cost, critical price, financial net present value and other important indicators, and a set of planning and research methods suitable for the integration of exploration and development in the western South China Sea is finally formed. This method has been applied to the replacement reserve study of Weizhou X and Weizhou Y oil fields. It is found that the planned reserves and production are consistent with the actual ones, and good practical results have been achieved.

南海黄鳍金枪鱼性腺发育形态观察和组织学研究

为了解南海黄鳍金枪鱼(Thunnus albacares)性腺发育规律和繁殖特征,2021年5月—2022年5月,用延绳钓在南海(17.41°N,110.61°E)采集黄鳍金枪鱼41尾,体质量0.6~35.0 kg,采用解剖和常规组织学方法,研究南海黄鳍金枪鱼的性腺发育周期和各发育时期性腺中生殖细胞的形态特征。结果表明,黄鳍金枪鱼卵母细胞发育共分6个时相,卵巢发育分为6个时期:卵原细胞增殖期、初级卵母细胞生长期、皮质液泡形成期、卵黄颗粒积累期、排卵期、退化期。黄鳍金枪鱼为分批非同步产卵类型;精巢为典型的小叶型,发育过程分为6个时期:精原细胞分化期、精原细胞增殖期、早期成熟期、中期成熟期、排精期、退化期。本文阐明了黄鳍金枪鱼性腺在不同发育时期的形态、组织结构特征及发育规律,以丰富黄鳍金枪鱼繁殖生物学基础资料,并为其人工繁育提供科学依据。

COMPARISON OF THE STRUCTURAL CHARACTERISTICS OF DEVELOPED VERSUS UNDEVELOPED MID-LEVEL VORTEXES

Using the NCEP 1°×1°reanalysis data,several obvious differences of the structural characteristics of developed versus undeveloped mid-level vortexes are studied.First,the central vorticity of the developed mid-level vortex increases towards higher levels while the undeveloped one decreases.The low-level convergence structure maintains well in the developed mid-level vortex whereas the undeveloped one does badly.Second,on the one hand,according to the symmetric analysis,the horizontal wind field and wind vertical section of the developed mid-level vortex are well symmetric while those of the undeveloped one are less symmetric.Meanwhile,weak wind vertical shear help the developed mid-level vortex to establish a warm core in upper-and mid-levels of the troposphere.On the other hand,according to the balance analysis,better balance between wind and pressure is shown in the mid-and lower-levels of the troposphere of the developed mid-level vortex than in those of the undeveloped vortex.Third,positive anomaly of potential vorticity is enhanced and developed in the vertical direction of the developed vortex.However,the undeveloped vortex weakens with a weak positive anomaly.

南海区拖网渔业发展趋势及其对渔业资源的影响

拖网是南海区海洋渔业生产最重要的渔具,拖网渔业在南海区海洋渔业生产中占主导地位。南海区拖网渔船数量从1986年的6730艘增长至2003年的14599艘,随后减少,2010年后基本维持在9000艘左右;其总吨位在212864~876045 t波动,呈显著上升趋势;而总功率从1986年的440438 kW上升至2005年的1735173 kW,之后呈下降趋势。1986—2020年单船平均吨位和功率均呈显著上升趋势。拖网渔船产量在59.24×10^(4)~181.66×10^(4)t之间波动,占南海区总捕捞产量的38.35%~62.96%,呈逐年下降趋势;单位功率和单位吨位的产量分别在0.72~1.40 t和1.18~3.90 t之间波动,1999年最高,之后呈下降趋势。根据8种重要经济鱼类幼鱼占比统计结果,1992—2020年底拖网渔获物中幼鱼生物量占比均值为24.35%~84.28%,数量占比均值为40.09%~89.84%,其中白姑鱼(Pennahia argentata)、带鱼(Trichiurus japonicus)和竹荚鱼(Trachurus japonicus)幼鱼比例最高。鉴于拖网渔业选择性不强,对幼鱼资源及海洋环境影响较大,建议逐步压减拖网渔船规模,严格执行网目尺寸和可捕规格制度,引导渔民使用资源节约型、环境友好型的作业方式,以利于近海渔业资源养护和可持续利用。

边疆治理视域下民国时期的南海开发政策及其影响

开发经营是国家在领土范围内宣示主权、行使管辖的重要标志之一。民国时期,南海主权危机加剧,为维护南海主权,巩固海疆安全,国民政府通过制定开发计划、招揽民间资本参与等方式推动南海诸岛的经营开发,是民国政府治理海疆的重要方式和内容。国民政府南海开发政策对于现阶段我国南海维权具有重要的推动作用,但也存在一定历史局限性,如开发内容单调,未能充分调动一切维权资源等。这与民国时期政治局势动荡,政府与社会各界对南海海疆的重视程度和认知水平尚存在不足、海疆治理人才匮乏、治理能力严重不足等因素有关。

全球发展倡议和全球安全倡议的地区实践与历史经验——关于中国-东盟推动区域合作与治理南海问题的考察

以《南海各方行为宣言》的发展为主线,分阶段考察中国与东盟国家治理南海问题和推进区域合作的互动进程可以看到,坚持和平共处的外交原则以及共同、合作与对话的安全观,坚持发展优先、致力于区域合作,坚持“东亚方式”与“双轨模式”,是中国与东盟国家妥处发展与安全议题的成功经验所在。这种地区经验与全球发展倡议、全球安全倡议的理念具有高度共同性,充分说明两大倡议来源于中国外交的长期实践。未来,面对美国发起对华全面战略竞争的地区变局,中国与东盟应坚持全球发展倡议和全球安全倡议的理念,继续聚焦区域经济合作,通过可持续性发展实现本地区的可持续性安全,从而确保南海形势的稳定并寻求最终解决之道。

南海岛礁生态现状、保护与发展策略

南海岛礁是我国实施南海开发的重要支点,对于保障南海开发的可持续性,维护国家权益与领土完整具有重要作用。南海岛礁生物多样性丰富,生态功能结构复杂,但同时生态脆弱易受人为因素干扰。本文系统总结了南海岛礁气候、水分、土壤、生物、农业发展的基本特点,指出南海岛礁发展应以生态可持续性为根本任务,减少人为因素对岛礁生态的影响,注重岛礁农业、现代海洋牧场等发展,构建南海岛礁生态可持续发展综合评价体系等对于保障南海岛礁社会、经济、国家安全服务功能的实现具有重要意义。

中国南海北部不同岛屿植被与土壤的耦合协调发展度

植被和土壤是陆地生态系统两个重要的组成部分,二者相互影响相互促进,探明两者的耦合协调关系是生态恢复与重建的顺利实施的关键。基于中国南海北部大庙墩岛、涠洲岛、大汉三墩岛、甘蔗岛和蜈支洲岛等个海岛的典型植被群落植被土壤的全面调查和取样分析,建立10个植被因子和14个土壤因子的2级层次指标体系,采用层析分析法确定各因子的权重,构建5个海岛植被土壤耦合度和耦合协调度模型。结果表明,不同岛屿的植被土壤耦合度和耦合协调度模型并不完全对应,植被与土壤的综合指数在不同岛屿中也不完全一致,甘蔗岛的植被效应和大汉三墩岛的土壤效应最佳。中国南海北部5个岛屿的植被土壤耦合协调状况较好,均处于初、中级协调发展状态,且除甘蔗岛外处于植被土壤同步型。总的来说,由于岛屿远离内陆,人类干扰相对较小,在植被土壤长期的演替过程中,中国南海北部岛屿植被土壤耦合协调较好,在其恢复与生态重建时要注重提高植物多样性、抚育水平和土壤管理水平。

中国南海天然气水合物开发面临的挑战与思考

初步勘查结果表明,中国南海具有广阔的天然气水合物(以下简称水合物)资源前景,并主要赋存于该区深水陆坡浅层未固结的泥质粉砂中,其开发过程集水合物相变、储层骨架溃散、气—液—固多相渗流与输运于一体,面临着单井产气量低、持续生产困难、有可能带来生态环境风险、经济效益低、难以实现规模化开发等问题。为了早日实现对该区水合物的商业化开采,梳理了全球主要地区水合物远景资源量、开采方法及试采进展;从中国南海水合物成藏机制、开采过程中气—液—固多相流连续排采、生态环境风险、技术与装备等方面,分析了其中的科学问题和工程技术挑战,阐释了水合物商业化开采之路坎坷艰难之原因。研究结果表明,尽管面临诸多挑战,但经过20多年的持续攻关,我国已经建立了相对系统的水合物基础物性、开采模拟与力学特性实验装备,奠定了进一步开展相关研究的理论、实验和装备基础,在海域水合物试采等部分技术领域处于国际领先水平;进而提出了“水合物和深部气等多气源合采”“CO_(2)水合物置换开发及固化封存”“海上多能种区域协同一体化开发”等有助于实现水合物商业开发的潜力路径,并分析了其技术原理和实现途径。

Has the Prediction of the South China Sea Summer Monsoon Improved Since the Late 1970s?

Based on the evaluation of state-of-the-art coupled ocean-atmosphere general circulation models （CGCMs） from the ENSEMBLES （Ensemble-based Predictions of Climate Changes and Their Impacts） and DEME- TER （Development of a European Multimodel Ensemble System for Seasonal to Interannual Prediction） projects, it is found that the prediction of the South China Sea summer monsoon （SCSSM） has improved since the late 1970s. These CGCMs show better skills in prediction of the atmospheric circulation and precipitation within the SCSSM domain during 1979-2005 than that during 1960-1978. Possible reasons for this improvement are investigated. First, the relationship between the SSTs over the tropical Pacific, North Pacific and tropical Indian Ocean, and SCSSM has intensified since the late 1970s. Meanwhile, the SCSSM-related SSTs, with their larger amplitude of interannual variability, have been better predicted. Moreover, the larger amplitude of the interannual variability of the SCSSM and improved initializations for CGCMs after the late 1970s contribute to the better prediction of the SCSSM. In addition, considering that the CGCMs have certain limitations in SCSSM rainfall prediction, we applied the year-to-year increment approach to these CGCMs from the DEMETER and ENSEMBLES projects to improve the prediction of SCSSM rainfall before and after the late 1970s.

南海共同开发管理机制研究

南海诸岛自古以来就是中国领土,但由于南海部分岛礁处于他国实控状态,由此部分形成了争议海域。为此,中国政府提出了“搁置争议,共同开发”的主张,但在实践层面并未大面积实现。本文通过梳理了南海具体争议海域、中国所主张的“搁置争议,共同开发”的实际含义、其他地区争议海域共同开发管理的成功案例以及争议海域共同开发的国际法依据,论证了南海争议海域共同开发的实践可行性。通过对具体的共同开发管理模式的分析,我国应选择联合管理模式,坚持领土主权,站在人类命运共同体的高度,和平解决南海争端。

中日东海共同开发两个重要分歧的法理分析

中日两国于2008年6月达成的《中日东海问题原则共识》,确定了一个面积约2700平方千米的共同开发区块。两国虽然就东海问题达成了原则共识,但仍存在两个重要分歧:一是“区块”跨越“中间线”是否意味着中国接受或承认日方所谓的“中间线”主张?二是“中间线”以西中国已开发的油气田是否为共同开发对象海域的一部分?由于上述分歧的存在,两国东海共同开发迄今仍未成功实现。关于第一个分歧,东海“区块”跨越“中间线”,但这并不意味着中国接受或承认日方所谓“中间线”主张。关于第二个分歧,中国认为,“中间线”以西中国已开发的油气田位于“无争议”的中国管辖海域,日本企业依据中国法律参与合作。中日落实2008年《中日东海问题原则共识》,需要就两个重要分歧达成谅解,未来也需要探讨更大范围重叠海域共同开发的问题。

基于重磁震资料的南海新生代盆地分布综合研究

作为西太平洋最大的边缘海,南海分布有30多个新生代沉积盆地,其蕴含着丰富的油气资源.但由于资料的限制,南海存在不同区域盆地研究程度不同,不同区域盆地面积差别较大,部分盆地只是坳陷而没有达到盆地的级别以及盆地外围可能存在凹陷等问题.南海新生代盆地分布问题制约了其油气分布规律、储量等基础地质问题的研究.本文以地震剖面数据为约束,以重力资料为主、辅以磁力资料,研究了南海新生代盆地分布及构造区划.通过提取新生代盆地及其构造单元引起的重力异常,结合地震剖面等资料反演了新生界底界面深度及新生界厚度.在充分调研已有盆地和构造单元划分方案的基础上,根据南海的地质及地球物理特征,确定了盆地及构造单元划分标准.以新生界厚度为基础并结合重、磁、震、地质等资料,进行地质-重磁震联合解释,将南海原有的36个盆地重新划分为24个盆地,盆地总面积扩大了约15万km^2.研究表明,南海新生代盆地沉积层厚度在1.5~16km之间,有6个北东东/北东向沉积坳陷带、2个近南北向沉积坳陷带以及1个三角沉积坳陷区;盆地展布方向主要为北东和北东东向,其次为北西和近南北向,呈现"南三北三"的分布特征.

南海黄鲷性腺发育的初步研究

本文采用常规的生物学调查方法并取黄鲷性腺做石蜡切片，用显微镜观察黄鲷的性腺发育，进行组织学研究．其结果表明，南海黄鲷精巢可分成6期，精巢5期的成熟度指数为1．62％～2．71％，平均值为1．99％．雌性生殖细胞可见5个时相，卵巢发育也相应分成6期，卵巢5期时的成熟度指数为8．90％～13．90％，平均值为9．45％．南海黄鲷的繁殖期在11月至翌年的4月，繁殖高峰在12月至3月，黄鲷的产卵类型属于在同一繁殖季节中多次产卵类型．本文还对黄鲷的雌雄同体现象、繁殖力、繁殖时间进行了讨论．

南海海盆海山古地磁及海盆的形成演化

根据海山磁性反演获取的古地磁成果发现,南海海盆东部和西南部的运动形式、生成时代存在很大差异,东部海盆和西南部海盆之间由一条北北西走向的岩石圈压性左旋转换(性)断层———"南海海盆中央断裂"分界.结合已有的地质地球物理成果分析和论证,确定了南海海盆在古南海和与之接壤的华南地块南部边缘形成.南海海盆的形成演化分四个阶段:第一阶段,始新世"古南海断裂"产生,古南海被一分为二;第二阶段,渐新世东部海盆开始发育———扩裂;第三阶段,中中新世西南部海盆开始发育———张裂;第四阶段,南海海盆整体旋转,古南海圈闭.