Identification of thermal front dynamics in the northern Malacca Strait using ROMS 3D-model

The thermal front in the oceanic system is believed to have a significant effect on biological activity.During an era of climate change,changes in heat regulation between the atmosphere and oceanic interior can alter the characteristics of this important feature.Using the simulation results of the 3D Regional Ocean Modelling System(ROMS),we identified the location of thermal fronts and determined their dynamic variability in the area between the southern Andaman Sea and northern Malacca Strait.The Single Image Edge Detection(SIED)algorithm was used to detect the thermal front from model-derived temperature.Results show that a thermal front occurred every year from 2002 to 2012 with the temperature gradient at the location of the front was 0.3°C/km.Compared to the years affected by El Ni?o and negative Indian Ocean Dipole(IOD),the normal years(e.g.,May 2003)show the presence of the thermal front at every selected depth(10,25,50,and 75 m),whereas El Ni?o and negative IOD during 2010 show the presence of the thermal front only at depth of 75 m due to greater warming,leading to the thermocline deepening and enhanced stratification.During May 2003,the thermal front was separated by cooler SST in the southern Andaman Sea and warmer SST in the northern Malacca Strait.The higher SST in the northern Malacca Strait was believed due to the besieged Malacca Strait,which trapped the heat and make it difficult to release while higher chlorophyll a in Malacca Strait is due to the freshwater conduit from nearby rivers(Klang,Langat,Perak,and Selangor).Furthermore,compared to the southern Andaman Sea,the chlorophyll a in the northern Malacca Strait is easier to reach the surface area due to the shallower thermocline,which allows nutrients in the area to reach the surface faster.

Study on characteristics of internal solitary waves in the Malacca Strait based on Sentinel-1 and GF-3 satellite SAR data

The study of the characteristics of internal solitary waves happened in the Malacca Strait is an urgent problem for submarine, ship navigation and marine engineering. Based on SAR remote sensing data obtained from the high spatial resolution Sentinel-1 and GF-3, the internal solitary wave characteristics of the Malacca Strait are investigated. By use of 20 Sentinel-1 SAR images from June 2015 to December 2016 and 24 GF-3 images from April2018 to March 2019, the spatial distribution characteristics of internal solitary wave s are statistically analyzed. It is found that the internal solitary waves are usually in the form of wave packets and single solitary waves, and the maximum crest length of the leading wave can reach 39 km. The amplitude and group velocity of internal solitary wave s can be calculated by the inversion model of high-order nonlinear Schrodinger(NLS) equation, and the calculated amplitude of the internal solitary wave s and the propagation group velocity of the wave packets range from 4.7 m to 23.9 m and 0.12 m/s to 0.40 m/s, respectively. The range of phase velocity of single internal solitary waves obtained by Kd V equation is 0.26 m/s to 0.60 m/s. In general, the amplitude and the velocity of internal solitary wave s in Malacca strait are related to the topography.

Spatial distribution and behavior of dissolved selenium speciation in the South China Sea and Malacca Straits during spring inter-monsoon period

Selenium(Se)has been recognized as a key trace element that is associated with growth of primary producers in oceans.During March and May 2018,surface water(67 samples)was collected and measured by HG-ICP-MS to investigate the distribution and behavior of selenite[Se(Ⅳ)],selenate[Se(Ⅵ)]and dissolved organic selenides(DOSe)concentrations in the Zhujiang River Estuary(ZRE),South China Sea(SCS)and Malacca Straits(MS).It showed that Se(Ⅳ)(0.14–3.44 nmol/L)was the dominant chemical species in the ZRE,related to intensive manufacture in the watershed;while the major species shifted to DOSe(0.05–0.79 nmol/L)in the MS,associated with the wide coverage of peatland and intensive agriculture activities in the Malaysian Peninsula.The SCS was identified as the northern and southern sections(NSCS and SSCS)based on the variations of surface circulation.The insignificant variation of Se(IV)in the NSCS and SSCS was obtained in March,potentially resulting from the high chemical activity and related preferential assimilation by phytoplankton communities.Contrastively,the lower DOSe concentrations in the SSCS likely resulted from higher primary production and utilization during March.During May,the concentration of Se(Ⅳ)remained low in the NSCS and SSCS,while DOSe concentrations increased notably in the SSCS,likely due to the impact of terrestrial inputs from surface current reversal and subsequent accumulation.On a global scale,DOSe is the dominant Se species in tropical oceans,while Se(Ⅳ)and Se(Ⅵ)are major fractions in high-latitude oceans,resulting from changes in predominated phytoplankton and related biological assimilation.

Variations in silicate concentration affecting photosynthetic carbon fixation by spring phytoplankton assemblages in surface water of the Strait of Malacca

The Strait of Malacca （SoM）, the world＇s busiest sea-route, is increasingly polluted as the rapid develop- ment of world trades, affecting phytoplankton primary productivity therein. The variations of surface phy- toplankton biomass, size-structure and carbon fixation were investigated across the SoM during the spring period （May 4 to 9, 2011）. Chlorophyll a concentration increased from 0.12 ptg/L at the northwest entrance of the SoM to a maximal 0.63 #g/L at narrowest section, and decreased to 0.10/.tg/L at the southeast entrance. Photosynthetic carbon fixation by phytoplankton coincided well with Chl a biomass, and increased from 10.8 to 22.3 pg C/（L.d）, then decreased to 9.21/zg C/（L.d）; while the carbon fixation rate showed an inverse pattern to the changes of Chl a, and decreased from 87.1 to 35.5 #g C/（#g Chl a.d） and increased thereafter to 95.3 btg C/（/2g Chl a.d）. Picophytoplankton cells （〈3/2m） contributed to more than 60% and 50% of the total Chl a and carbon fixation at both the entry waters; while the contributions of pico-cells decreased sharply to the minimum of 18.3% and 27.5% at the narrowest part of the SoM. In particular, our results showed that the silicate concentration positively regulated Chl a biomass and carbon fixation, reflecting that the higher silicate favoured the growth of phytoplankton and thus led to higher primary production in this strait.

SPATIAL VARIATION OF Zn GEOCHEMICAL FRACTIONS IN THE SURFACE SEDIMENTS OF THE STRAITS OF MALACCA: NATURAL OR ANTHROPOGENIC?

Total concentrations of Zn in the sediments of the offshore and intertidal areas of the west coast of Peninsular Malaysia were recently reported in the literaturs. However, total concentrations of metals in the sediment samples do not reflect the portion or carrier phase which is attributable to anthropogenic activities and those of natural origins. In this work, geochemical fraction of Zn in the sediments of the same areas was studied and the potential use of CV as an indicator of Zn pollution was determined. The geochemical study by using sequential extraction technique revealed that nonresistant fraction of the offshore and intertidal sediments (summation of ‘easily or freely leachable and exhangeable (EFLE)’, ‘acid-reducible’ and ‘oxidisable-organic’) covered about 30% and 48% of total zinc concentrations, respectively, in the sediments while most of the total zinc concentrations (offshore: 70%; intertidal: 52%) found in the sediments could be mostly due to natural origins (nonresistant fraction). Thus, the Zn levels in the Straits of Malacca should not pose a risk to the living organisms. Based on Spearman’s correlation coefficients, the source of Zn contamination in the Straits of Malacca was mainly contributed by the intertidal coastal area rather than offshore area. The present study also indicated the coefficient of variation can be used as a potential indicator of total summation of geochemical Zn concentrations in the coastal sediment but of different geochemical of Zn needs further validation.

Heavy Metal Concentrations in Sediment and Intertidal Gastropod Nerita lineata from Two Opposing Sites in the Straits of Malacca

The concentrations of Cd,Cu,Pb,Zn,Ni and Fe were determined in the surface sediment and marine gastropod Nerita lineata collected in May 2005 from the intertidal zone of Dumai,Sumatera,Indonesia and Johor,Peninsular Malaysia.The results showed that metal concentrations in sediment and the soft tissue of N.lineata varied at different sampling stations.Mean heavy metal concentrations were 0.92 μg/g(Cd);6.40 μg/g(Cu);32.77 μg/g(Pb);54.41 μg/g(Zn);11.56 μg/g(Ni) and 2.97%(Fe) in sediment from Dumai and 1.15 μg/g(Cd);26.73 μg/g(Cu);53.45 μg/g(Pb);130.77 μg/g(Zn);20.79 μg/g(Ni) and 2.72%(Fe) in sediment from Johor.Concentrations of metals in gastropod N.lineata were 0.71 μg/g(Cd);15.16 μg/g(Cu);9.35 μg/g(Pb);94.69 μg/g(Zn);5.08 μg/g(Ni) and 397.97 μg/g(Fe) in samples from Dumai and 1.24 μg/g(Cd);18.02 μg/g(Cu);19.75 μg/g(Pb);95.09 μg/g(Zn);5.57 μg/g(Ni) and 473.56 μg/g(Fe) in samples from Johor.Although they were not statistically significant(p>0.05),heavy metal concentrations in N.lineata were correlated with the concentrations of respective metals in sediment in both samples from Dumai and Johor.In general,samples of sediment and gastropod from Johor accumulated significantly higher heavy metal concentrations when compared to samples from Dumai(p<0.05).Higher concentrations of metals were recorded in samples collected from the stations close to the industrial and anthropogenic activities in both Dumai and Johor areas.However,most of the concentrations were still comparable to the previous reported studies from other geographical areas.

海上丝路与马六甲海峡

东汉时期横贯亚、非、欧三大洲的海上丝路形成以后,马六甲海峡的重要性越来越凸显。公元7世纪,马六甲海峡出现了一个室利佛逝国,宋以后中国史籍改称三佛齐,依靠控制水道要冲向过往船商征税而致富,发展成一个强大的经济王国。中国与之保持友好外交关系,从而使海上丝路得到发展。明朝郑和七下西洋时,帮助满剌加立国,调解满剌加与暹罗的纷争,用武力平定海盗,保持马六甲海峡通畅,使海上丝路达到极盛。16世纪中叶西方人占领马六甲海峡,并建立海峡殖民地,导致海上丝路的衰败。当前,中国提出建设21世纪海上丝路的发展计划,得到沿线国家的支持和拥护。但美国为了遏制中国,企图用军事手段控制马六甲海峡。为此,本文回顾与探讨开凿克拉运河的争论历史与对策。

基于盲数理论的我国海上战略通道安全风险评价

对我国海上战略通道进行安全风险评价是保障海上通道安全的重要环节.由于海上战略通道的安全风险具有多种不确定性,故可运用盲数理论建立我国海上战略通道安全风险等级评价的盲数模型.通过专家打分的方法对影响因素进行未确知测度,构造判断矩阵获得影响因素的权重,从而得到模型的综合未确知测度,根据既定的评价准则获得海上通道的安全风险级别.文中对我国重要的海上通道马六甲海峡进行了安全风险评价,其评价结果为:马六甲海峡的安全级别为较危险级别,验证了该盲数模型的有效性.

马六甲海峡—南海航线与当代中国经济发展

中国大陆东部受太平洋板块向亚洲大陆板块的俯冲,形成一系列岛链,而岛链间的海峡是中国通往世界的咽喉水道.2004年中国国内生产总值136515亿元人民币（约为16854亿美元）,外贸交易总额达11548亿美元,其中90%以上的对外贸易是通过海洋运输实现的,而马六甲海峡-南海航线最为重要.马六甲海峡位于巽他陆架上,水深25～113m,航道仅宽2.7～3.6km;南海是西北太平洋最大的边缘海,海底地貌复杂,珊瑚礁滩广布,地质构造及海底地貌情况决定了中国国际运输航线是经过南海西沙群岛和中沙群岛之间的中沙海槽,向南通过南沙群岛西侧西卫滩与李准滩之间,通过马来半岛-侧马六甲海峡主航道进入印度洋的.这条航线是中国能源、贸易运输的咽喉,包括有：1）中国石油进口主要地区.中东（占总进口的50.79%）和非洲（占总进口的24.63%）均要经过马六甲海峡-南海航线;2）马六甲海峡-南海航线是中欧贸易和中国-美国东部贸易咽喉;3）马六甲海峡-南海航线是中国与东亚港口的生命线.

基于多时相遥感数据的海岸线自动提取方法

海岸线是海洋的重要组成部分,对于海域管理具有重要意义。本文根据岸线位置确定原理,即将多时相瞬时水边线上边界近似作为海岸线,提出了一种基于多时相水边线的海岸线自动提取方法,该方法应用区域生长与边缘检测相结合的方法提取瞬时水边线,然后采用海岸线自动判别算法进行海岸线的提取。首先计算归一化水体指数(normalized difference water index,NDWI)图像,利用区域生长算法进行海陆分割,得到海陆分割二值图;然后利用Canny边缘检测对海陆分割结果进行边缘检测,得到瞬时水边线;最后利用海岸线自动判别算法得到多时相瞬时水边线上界作为海岸线。本文以马六甲海峡部分海岸作为研究区域,应用多期Landsat 8遥感影像进行了海岸线提取和分析。为验证海岸线提取精度,对获取时间接近高潮时的一景哨兵二号影像进行目视解译得到人工解译的海岸线,与本文提取海岸线进行对比。结果显示,本文算法得到的海岸线平均偏移量和均方根误差分别为21.01 m和21.96 m,能够满足30 m分辨率遥感图像的精度要求,相比采用单景影像提取海岸线,精度有明显提高。

马六甲海峡安全问题与中国的政策选择

马六甲海峡正面临着来自传统安全和非传统安全的双重挑战。新马印尼三个沿岸国除了通过加强巡逻与监管来增强安全系数外,还根据马六甲海峡的地缘特点和安全问题性质,主导性地推动了多层面的安全合作。中国在面对马六甲海峡所存在的安全问题时,应从战略高度来制定和实施相关政策,努力降低马六甲海峡通道使用上可能存在的脆弱性,实现海上运输安全。

海洋烷烃降解菌Alcanivorax sp．A-11-3的分离鉴定及其降解酶基因研究

从马六岬海峡的表层海水中分离到一株石油降解菌A-1l-3．经16SrDNA Blast结果表明其与Alcanivorax borkumensisSK2具有最高相似性为96％，该菌可能是食烷菌属的一个新种．该菌具有很强的石油降解能力．结果表明，A—11—3对烷烃的降解范围较宽，能以C8～C36的烷烃为唯一碳源和能源生长；在7d内该菌对柴油的降解率达到49．5％．此外，还从菌株中克隆到了大小为426bp的烷烃羟化酶基因alkB片段和843bp的P450烷烃羟化酶基因的部分序列．序列分析表明，alkB片段编码的氨基酸序列与4．60rkumensis SK2^T的AlkB1和AlkB2的同源性分别为57．75％和40．14％；该菌的P450与SK2菌株的P450具有最高同源性，为87％．研究结果对于海洋石油降解微生物生态研究及石油污染生物修复技术开发有参考价值．

马六甲海峡与南海航道安全

马六甲海峡是世界上最重要的海上交通航线之一,其安全的主要问题是海盗的袭击。在反海盗的过程中,如何处理好海峡沿岸国家的主权问题成为确保马六甲海峡安全的关键。美、日、印度三国以反海盗袭击和打击恐怖主义为名,在南海海域加强军事合作,其真正目的据说是牵制中国,这无疑增加了南海航道的不安全因素。

中缅石油管道设计中的美印因素

中国的石油绝大多数从中东和非洲进口。鉴于目前马六甲海峡的形势,中国应该修建一条从缅甸西部的实兑深水港到昆明的输油管道。中国的企业和地方政府支持修建中缅石油管道计划。但是,要把这项计划变成现实,还需要克服许多障碍。

论马六甲海峡溢油应急反应合作机制的构建

面对马六甲海峡日益增大的海上溢油风险,应通过建立定期会议制度、领导机构运行管理制度、资金保障制度、技术互助制度以及争端解决和责任追究制度,构建马六甲海峡溢油应急反应合作机制。这不仅可以弥补马六甲海峡合作机制在溢油事故应急处理方面的缺失,且将从合作方式、合作范围、合作义务的性质以及国际海事组织在合作中的作用等方面为完善《联合国海洋法公约》第43条提供示例。

马六甲海峡的潮汐特征分析

马六甲海峡是亚洲东南部的重要海峡通道,沟通太平洋和印度洋,具有重要的经济和战略地位。本文利用马六甲海峡及其毗邻海域验潮站的实测水位资料,分析了马六甲海峡及马来半岛东岸的潮汐特征。研究表明,半日分潮平均振幅最大的区域位于马六甲海峡内部,而全日分潮平均振幅最大的区域为马来半岛的东海岸。马六甲海峡内部以正规半日潮为主,马来半岛东侧则为混合潮港,北部为不正规全日潮,南部则为不规则半日潮。半日分潮M2,S2和全日分潮K1在马六甲海峡内的传播为自西北向东南,而全日分潮O1则为自东南向西北方向。马来半岛东岸的半日潮传播方向以中部的Cendering站为分界线,南、北两部海区分别向南、向北相背传播,而全日潮传播方向相同,统一为自北向南。

马六甲海峡与东南亚地区安全

马六甲海峡面临海盗与恐怖分子的威胁,海峡沿岸国———印度尼西亚、马来西亚和新加坡为维护海峡安全,执行了一系列安全措施,但由于力量有限,故要求海峡使用国"负担分摊"。而海峡使用国因涉及到主权的敏感问题,只能提供有关培训、设备和信息情报等援助。这些情况说明,保卫马六甲海峡安全的任务应由海峡沿岸国和海峡使用国共同承担,只有通过密切的国际合作,才能确保马六甲海峡与东南亚地区安全,才能有效地打击海盗和恐怖主义活动。

马六甲海峡崛起的历史逻辑--郑和七下西洋七至满剌加考实

历史上的马六甲海峡名不见经传。国际上习惯以马六甲称呼该海峡,是以海峡得名于著名国际贸易港口马六甲(Melaka,原称Malacca),即今马来西亚马六甲州首府马六甲市。马六甲是满剌加的音译,由满剌加衍变而来,是海峡专有称呼,始自15世纪初满剌加王国的兴起,并逐渐形成重要国际贸易港口城市。满剌加王国兴起与海峡崛起密不可分,海峡崛起与郑和七下西洋有着紧密联系。迄今一般认为郑和下西洋五次到达满剌加,也就是从第三次下西洋算起,这一问题因《明实录》失载郑和第一次下西洋出发时间,同时也失载首次前往满剌加赍诏封王的使臣之名,形成悬案一直没有解决。郑和七下西洋每次必到满剌加,确定为七次,需要进行全面考证,以彰显海峡的重要。郑和第一次下西洋就消除了海峡的海盗问题,为海峡安全建立保障,对于海峡崛起发挥了至关重要的作用。从全球史的视野出发,我们对郑和下西洋的研究,不仅是在追踪明代中国揭开人类大航海序幕的轨迹,还涉及如何看待和理解全球史的重大问题。郑和下西洋如何改变了世界?对此可以从满剌加海峡的崛起来理解。

试析我国能源运输战略

马六甲海峡是世界上最危险和最重要的战略要冲之一。专家们认为,它是世界上最容易受到攻击的10大目标之一。控制马六甲海峡是目前美国的主要战略目标,即使可能导致它与该地区的国家甚至和中国发生武装冲突也在所不惜。如果泰国的克拉运河计划最终能够得以实现,一定会给该地区的自由贸易和海运事业带来共同利益。但对中国来说, 必须把缅甸通道和克拉运河区别开来。

东南亚海盗问题:合作与前景

海盗活动自古有之。冷战后,东南亚海域成为海盗活动最猖獗的地方,该地区各国加大了打击海盗的力度。海盗问题产生的复杂原因、各国对海盗的界定及对海盗威胁程度的认知不一影响了打击海盗的绩效。海盗活动的蔓延引起了东南亚周边大国的关注,给东南亚海域国家造成了一定的压力,也促使各方实行各种形式的合作。近期内,大国军事人员直接参与反海盗联合行动的可能性不大。