The South China Sea Issue in Foreigners' Eyes

An arbitral tribunal of the Permanent Court of Arbitration(PCA)in The Hague issued an award on July 12 on the South China Sea case unilaterally initiated by the Philippines.The Chinese government issued a statement saying that the award was null and void and had no

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

SPATIAL PATTERN OF THE AIR-SEA INTERACTION NEAR THE SOUTH CHINA SEA DURING WINTER

This paper delineates the coupled and principal pattrns of sea surface temperture (SST) and surface wind near the South China Sea (SCS), and discusses the mechanisms of air-sea coupling near the SCS and their asspcoiation with the Asian monsoon. Singular value decomposition (SVD) and single field principal component analysis (PCA) are applied to the so and wind anomalies from the 1979 - 1995 NCEP/NCAR reanalysis data.The leading SVD mode explains a predominant amount of squared covariance between the SST and zonal or meridional wind. During winte, the meridional wind’s relation to the SST is betterr than the relation of zonal wind to ase. Despite the large magnitude of the squared covariance between SST and zonalor meridional wind, the spatial patterns of the first mode of SVD between the SST and meridional wind are similar. They both exhibit ellipe-shaped variance with the center near the SCS and a northeast-southwest oriented main axis. The spatial patterne of the leading mode of SVD between the SST and zonal wind are also similar to a certain degree. The zonal wind is not as closely correlated to the SST as the meridional wind is. These results suggest that the meridional wind and SST are stronly coupled during the winter season, and that there is a certain coupled action system in the SCS.

Observation of interactions between internal tides and near-inertial waves after typhoon passage in the northern South China Sea

During the observational period of our study,Typhoon Hagupit passed over the mooring site and induced strong near-inertial waves(NIWs),which provided an opportunity to investigate the interactions between internal tides(ITs) and NIWs. Based on the mooring data,we compared the current spectra during the typhoon period and non-typhoon period in the northern South China Sea,and found that the highfrequency waves(f D 1 and f D 2) were evident during the former. Moreover,the observations of the current revealed that f D1 and f D 2 occurred near the depth of strong vertical shear in the NIWs. In order to confirm the generation mechanism of f D1 and f D 2,we compared the positions of strong vertical shear in the NIWs and strong vertical velocity in the ITs. It was established that the vertical shear of the horizontal current of the NIWs and the vertical current of the ITs contributed to the generation of f D1 and f D 2.

Wave-current interaction during Typhoon Nuri(2008)and Hagupit(2008):an application of the coupled ocean-wave modeling system in the northern South China Sea

The northern South China Sea(SCS) is frequently affected by typhoons. During severe storm events, wave-current interactions produce storm surges causing enormous damage in the path of the typhoon. To evaluate the influence of wave-current interactions on storm surge, we used a coupled ocean-atmospherewave-sediment transport(COAWST) modeling system with radiation-stress and vortex-force formulations to simulate two typically intense tropical storms that invaded the SCS, namely Typhoons Nuri(2008) and Hagupit(2008), and compared results with observations from the Hong Kong Observatory. Both radiationstress and vortex-force formulations significantly improved the accuracy of the simulation. Depending on which typhoon and the topography encountered, the influence of surface waves on the oceanic circulation showed different characteristics, including the differences of range and intensity of storm surge between vortex-force and radiation-stress experiments. During typhoon landing, strong sea-surface elevation in concert with wave set-up/set-down caused the adjustment of the momentum balance. In the direction perpendicular to the current, but especially in the cross-shore direction, the pressure gradient and wave effects on the current dominated the momentum balance.

Overview of the South China Sea Monsoon Experiment

The present paper gives an overview of the key project ' South China Sea Monsoon Experiment (SCSMEX)' operated by the Ministry of Science and Technology of China during the period of 1996-2001. The SCSMEX is a joint atmospheric and oceanic field experiment which aims to better understand the onset, maintenance, and variability of the summer monsoon over the South China Sea (SCS). It is a large-scale international effort with many participating countries and regions cooperatively involved in this experiment. With the field observation in May-August 1998, a large amount of meteorological and oceanic data was acquired, which provides excellent datasets for the study of the SCS monsoon and the East Asian monsoon and their interaction with the ocean. The preliminary research achievements are as follows. (1) The earliest onset of the Asian monsoon over the SCS and Indo-China Peninsula has been well documented. Prom the viewpoint of the synoptic process, its onset is closely related to the early rapid development of a twin cyclone to the east of Sri Lanka. The conceptual modei of the SCS monsoon onset in 1998 was put forward. The 50-year time series of the SCS monsoon onset date was also made. (2) Two major modes, namely the 30-60-day and 10-20-day oscillations were ascertained. The influences of the abnormal SCS monsoon on the precipitation over eastern China and its modes were identifled. A strong (weak) monsoon over the SCS usually leads to less (more) precipitation over the middle and lower reaches of the Yangtze River basin, and more (less) precipitation in North China. (3) During the monsoon onset over the SCS, a wide variety of organized mesoscale convective systems (MCSs) were observed by a Doppler radar array deployed over the northern SCS. The relationship between large-scale circulations and MCSs during the monsoon onset process in 1998 was clearly revealed. It was suggested that there is a kind of positive feedback mechanism between large-scale circulations and MCSs. (4) The SST over the SCS during the early period influences the timing of the monsoon onset date and the monsoon's intensity. During the monsoon onset, the ocean undergoes a process of energy release through air-sea interaction. During the break phase of the SCS monsoon, the ocean demonstrates the process of energy re-accumulation. Obvious differences in the air-sea turbulent flux exchange between the southern and northern parts of the SCS due to different characteristic features of the atmosphere and sea structure were observed in those regions. (5) The verification of impact of intensive observations on the predictive performance is made by the use of regional models. The air-sea coupled regional climate modei (CRCM) was also developed under the SCSMEX Project . The simulation of the oceanic circulation in 1998 produced with the modei was well compared with the observations.

Interannual variability in the onset of the South China Sea summer monsoon from 1997 to 2014

本文基于南海地区850 hPa风场,降水以及海温定义了南海夏季风爆发指数,将南海季风爆发过程分为季节转换和季风爆发两个过程来进行研究。对18年的观测分析发现,南海季风爆发可归纳为三种情况:第一种是季风正常爆发,随着季节转换结束后,西南季风和降水在南海地区有明显增强;第二种是间接性爆发,在季节转换结束后,西南季风和降水的建立不是特别明显;第三种是推迟爆发,在季节转换结束后,南海地区没有建立西南季风也没有降水产生。进一步研究发现,西太副高异常西伸是导致南海季风延迟爆发的重要因素之一。此外,大尺度环流背景ENSO的影响也对南海季风爆发时间的早晚有重要影响,但并不是唯一决定性因素,印度洋和亚洲大地形的局地热力差异变化是影响季风爆发的另一重要因素。

Scientific questions about South China Sea ocean dynamics

South China Sea, its circulation and connection with other parts of the world oceans, poses important scientific questions. From the prospective view, we postulate ten key research directions to be pursued in the coming future, including ventilation of a monsoon dominated sea, water mass formation/transformation, heat/salt and water mass balance, energetics and mixing, mesoscale eddies, the role of typhoon, deep circulation and paleoclimate records, interaction with adjacent oceans, upwelling and ecology system, and response to climate changes.

Atmospheric Response to Mesoscale Ocean Eddies over the South China Sea

The South China Sea（SCS） is an eddy-active area. Composite analyses based on 438 mesoscale ocean eddies during 2000–2012 revealed the status of the atmospheric boundary layer is influenced remarkably by such eddies. The results showed cold-core cyclonic（warm-core anticyclonic） eddies tend to cool（warm） the overlying atmosphere and cause surface winds to decelerate（accelerate）. More than 5% of the total variance of turbulent heat fluxes, surface wind speed and evaporation rate are induced by mesoscale eddies. Furthermore, mesoscale eddies locally affect the columnar water vapor, cloud liquid water, and rain rate. Dynamical analyses indicated that both variations of atmospheric boundary layer stability and sea level pressure are responsible for atmospheric anomalies over mesoscale eddies. To reveal further details about the mechanisms of atmospheric responses to mesoscale eddies, atmospheric manifestations over a pair of cold and warm eddies in the southwestern SCS were simulated. Eddy-induced heat flux anomalies lead to changes in atmospheric stability. Thus, anomalous turbulence kinetic energy and friction velocity arise over the eddy dipole, which reduce（enhance） the vertical momentum transport over the cold（warm） eddy, resulting in the decrease（increase） of sea surface wind. Diagnoses of the model＇s momentum balance suggested that wind speed anomalies directly over the eddy dipole are dominated by vertical mixing terms within the atmospheric boundary layer, while wind anomalies on the edges of eddies are produced by atmospheric pressure gradient forces and atmospheric horizontal advection terms.

Peat formation and accumulation mechanism in northern marginal basin of South China Sea

In the present study,the coal-rock organic facies of Oligocene Yacheng Formation of the marginal basin in the South China Sea were classified and divided.In addition,through the correlations of the large-scale coal-bearing basins between the epicontinental sea and the South China Sea,it was concluded that the coal forming activities in the South China Sea presented particularity and complexity.Furthermore,the coal forming mechanisms also presented distinctiveness.The marginal basins in the South China Sea consist of several large and complex rift or depression basins,which are distributed at different tectonic positions in the South China Sea.Therefore,the marginal basins in the South China Sea are not simple traditional units with onshore continental slopes extending toward the deep sea.The marginal basins are known to consist of multi-level structures and distinctive types of basins which differ from the continental regions to the sea.During the Oligocene,the existing luxuriant plants and beneficial conditions assisted in the development of peat.Therefore,the Oligocene was the significant period for the formation and aggregation of the peat.However,the peat did not form in unified sedimentary dynamic fields,but instead displayed multi-level geographical units,multiple provenance areas,instability,and nonevent characteristics.As a result,the marginal basins in the South China Sea are characterized by non-uniform peat aggregation stages.In another words,the majority of the peat had entered the marine system in a dispersive manner and acted as part of the marine deposits,rather than during one or several suitable coal-forming stages.These peat deposits then became the main material source for hydrocarbon generation in all of the marginal basins of the South China Sea.The study will be of much significance for the hydrocarbon exploration in the marginal basins of the South China Sea.

Relationship between South China Sea Precipitation Variability and Tropical Indo-Pacific SST Anomalies in IPCC CMIP5 Models during Spring-to-Summer Transition

The present study evaluates the precipitation variability over the South China Sea（SCS） and its relationship to tropical Indo-Pacific SST anomalies during spring-to-summer transition（April–May–June,AMJ） simulated by 23 Intergovernmental Panel on Climate Change Coupled Model Intercomparison Project Phase 5 coupled models.Most of the models have the capacity to capture the AMJ precipitation variability in the SCS.The precipitation and SST anomaly（SSTA） distribution in the SCS,tropical Pacific Ocean（TPO）,and tropical Indian Ocean（TIO） domains is evaluated based on the pattern correlation coefficients between model simulations and observations.The analysis leads to several points of note.First,the performance of the SCS precipitation anomaly pattern in AMJ is model dependent.Second,the SSTA pattern in the TPO and TIO is important for capturing the AMJ SCS precipitation variability.Third,a realistic simulation of the western equatorial Pacific（WEP） and local SST impacts is necessary for reproducing the AMJ SCS precipitation variability in some models.Fourth,the overly strong WEP SST impacts may disrupt the relationship between the SCS precipitation and the TPO–TIO SST.Further work remains to be conducted to unravel the specific reasons for the discrepancies between models and observations in various aspects.

Observations of semidiurnal M 2 internal tidal parametric subharmonic instability in the northeastern South China Sea

Near-diurnal vertically-standing waves with high vertical wavenumbers k z were observed in the velocity and shear fi elds from a set of 75-d long ADCP moored in the northeastern South China Sea(SCS)away from the“critical”latitude of 28.8°.These enhanced near-diurnal internal waves followed a fortnightly spring-neap cycle.However,they always happened during semidiurnal spring tides rather than diurnal springs although strong diurnal internal tides with the fortnightly spring-neap cycle were prevailing,suggesting that they were generated via subharmonic instability(PSI)of dominant semidiurnal M 2 internal tides.When two semidiurnal internal tidal waves with opposite vertical propagation direction intersected,both semidiurnal subharmonic and super harmonic waves were largely intensifi ed.The observed maximum diurnal velocity amplitudes were up to 0.25 m/s.The kinetic energy and shear spectra further suggested that frequencies of daughter waves were not always perfectly equal to M 2/2.The superposition of two daughter waves with nearly equal frequencies and nearly opposite k z in a PSI-triad leaded to the vertically-standing waves.

A Review of Ocean-Atmosphere Interaction Studies in China

A large number of papers have been published and great efforts have been made in the recent 20 years by the Chinese oceanographic and meteorological scientists in the ocean-atmosphere interaction studies. The present paper is an overview of the major achievements made by Chinese scientists aad their collaborators in studies of larger scale ocean-atmosphere interaction in the following oceans： the South China Sea, the Tropical Pacific, the indian Ocean and the North Pacific. Many interesting phenomena and dynamic mechanisms have been discovered and studied in these papers. These achievements have improved our understanding of climate variability and have great implications in climate prediction, and thus are highly relevant to the ongoing international Climate Variability and Predictability （CLIVAR） efforts.

印-太暖池高温暖水的移位与南海夏季风爆发

为了揭示高温暖水在中国南海(文中简称南海)夏季风爆发中所起的作用,依据欧洲中期天气预报中心发布的第5代全球大气海洋再分析资料,发现气候平均意义下印度洋—太平洋暖池中30℃以上高温暖水会在5月出现移位:5月上旬高温暖水出现在孟加拉湾中部,而到下旬消退并移位到南海南部。通过分析局地天气尺度的海洋-大气相互作用过程,揭示了上述高温暖水月内移位的物理机制:在孟加拉湾夏季风爆发后,逐渐增强的潜热释放和减少的短波辐射会导致孟加拉湾高温暖水的面积逐渐缩小;与此同时,在副热带高压影响下,南海菲律宾岛西南高温暖水出现,并因其面积逐渐增大,并与泰国湾的高温暖水共同构成了南海南部的高温暖水。研究发现南海季风爆发几乎都出现在上述高温暖水移位之后,因此孟加拉湾中部和南海南部海表温度的差由正转负可以作为南海季风爆发的先兆。

中美博弈:近昔和当今及对中国战略的意涵

过去15年里,中美关系的首要特征是博弈而非协调。两国博弈先在战略阵线开启,继而在战略、经贸、高技术和意识形态四条主要阵线展开。就中美博弈总体而言,美国处于“防守型”战略态势,美国认为它长时期拥有的重大优势地位一个又一个地丧失或被侵蚀,首要动能在中国一边。中共十八大以来,中国逐渐成为一个急剧腾升的强国。大为增强的国力,使中国更加坚定了自信和抱负。中国内外发力,争取在世界政治经济和全球治理的某些问题领域参与引领甚或单独引领,实现在亚洲大陆以及发展中世界的经济和外交优势,大致取得在西太平洋的对美战略和军事优势,进一步地,对第一至第二岛链之间的战略空间的控扼能力愈益被视为必要。回顾奥巴马、特朗普和拜登三届美国政府的对华态势和政策,对未来中美关系应做好准备应对可能的疾风暴雨。

20世纪70年代以来域外国家介入南海问题研究:发展演变与未来趋势

域外各国对当代南海问题的关注和研究始于20世纪70年代,至今大致经历了《南海各方行为宣言》(DOC)达成前的早期阶段、DOC达成至“南海仲裁案”之间的阶段和中美竞争加剧后的新发展时期这3个阶段。在早期阶段,域外大国学界和智库虽然也对南海问题有不同的观点,但其立场和态度总体上是对中国有利的。第二阶段后期特别是中美竞争加剧后,其研究成果体现的对待南海问题的立场和态度逐渐多元化,研究方法也日益多元化,研究领域逐渐由传统领域向非传统领域扩展。与此同时,相关研究中对中国不利的结论和声音逐渐增多,这使得中国在国际舆论斗争和南海维权斗争中面临着更为严峻的挑战。上述变化受到各国研究人员代际更替、国际海洋法新发展和国际格局变迁的多重影响,但根本原因则是国际格局变迁及相关国家对本国利益的自我选择。中国应充分认识到国际规则和国际法的工具性作用,以平和的心态看待域外各国在南海问题各领域研究取向的变化,坚决反对歪曲或有选择地援引国际法来“抹黑”中国的行为;同时又要保持战略自信和战略耐心,努力加强和深化对国际法、国际政治和历史等不同学科交叉互融的研究,提高阐释运用国际法的能力,援引恰当的条款来维护中国的正当海洋权益。

南海地区新局势、新挑战与新思路——2023年度“南海论坛”综述

2023年南海地区局势复杂多变,危机频发,南海问题依然是全球最为复杂的海洋争端和影响中国-东盟关系的重要因素。如何在中美战略博弈大背景下应对亚太海洋安全新形势,相关问题亟须深入的探讨与总结。在南京大学中国南海研究协同创新中心主办的2023年度“南海论坛”上,与会专家围绕南海维权维稳斗争的新形势与新问题、美国与小多边机制干涉南海的挑战与应对、南海岛礁主权与海洋权益的历史视角和法律斗争新态势与新挑战,以及增进南海合作的新思路新办法等议题进行了深入讨论。面对法律、认知、话语斗争等诸多形势变化,中国需要进一步强化证据链建设和话语权构建,结合具体条件重塑相关实践的规范性,增进南海合作和共同开发。

从敌人到战略伙伴:越美关系发展的原因与限度

2023年9月,越南与美国领导人在河内宣布建立全面战略伙伴关系,越美关系进入历史最好时期。为何越南与美国能从曾经的生死敌手演变为如今的战略伙伴?在越美关系的演变历程中,两国关系的发展受到多重因素的综合影响。首先,越美两国对解决越战遗留问题的积极态度有助于消解双方对彼此负面的历史记忆,为两国关系改善提供了前提条件。其次,大国关系变化也催化了越美关系发展。冷战后期越南跟随苏联主动改善与美国关系,实现了关系正常化并开展初步合作。自2009年起,随着美国发起对华竞争并拉拢越南,越美关系进入战略合作阶段。最后,越南对美国的发展需求、安全需求与美国对越南的经济战略需求和安全战略需求相交织,共同推动了越美合作水平的不断提升。然而,越美战略合作进一步发展仍存在制约因素,包括两国意识形态分歧、美国可靠性不足及越南避免“选边站队”的政策倾向。对此,中国在大国竞争的变局下应未雨绸缪,通过理性审慎的对越政策,管控分歧、推进合作,妥善处理好中越关系。

中美战略竞争与东盟内部凝聚力

在地区权力加速转移的背景下,东南亚成为中美两国战略博弈的重要地缘方向。东盟的内部凝聚力是指东盟各国能否就某一议题达成政策共识,并形成东盟层面一致决策的组织向心力。文章认为,中美之间日趋激烈的竞争态势将严重削弱东盟的内部凝聚力,中美竞争烈度的不断攀升可能导致东盟内部在部分议题上难以达成一致意见。中美竞争作用于东盟共识的过程包含以下三个递进的层次:首先,中美竞争烈度的上升及两国对东盟不断加注的行为使东盟面临“选边站”的压力,东盟国家被迫在中美之间作出选择。其次,由于国家实力、联盟关系、领土冲突及历史记忆对东盟国家领导人的不同作用,东盟内部在“选边站”的立场上出现严重分歧。最后,以“东盟方式”为核心的东盟决策机制无法有效弥合东盟内部的分歧,东盟在中美博弈的重要议题上陷入决策困境。东盟国家在应对南海争端、“印太战略”上的政策分歧表明,中美逐渐凸显不兼容性的竞争正在激起东盟国家内部的立场差异。未来以地区制度为中心的大国竞争可能对东盟的区域影响力造成一定影响。