黄海和东海表层悬沙浓度年际变化特征

运用547 nm反射率、海表温度和海表风场遥感数据,分析了黄、东海表层悬沙浓度的年际变化特征、影响因素和形成机理。研究区近岸海域表层悬沙浓度较高,远离陆地的海域悬沙浓度一般较低,且存在明显的季节变化,其季节变化的敏感区(变化较大的区域,其反射率差大于1%)为浑浊羽状流分布区域和近岸海域。该羽状流从江苏海岸向东偏南方向延伸至黄、东海陆架中部,其边界以4 mg/L表层悬沙浓度为标志,冬季最盛,夏季最弱,甚至消失。研究区表层悬沙浓度也存在明显的年际变化,其冬季敏感区为浑浊羽状流与朝鲜半岛之间的海域(即羽状流东北部)、台湾海峡、近岸海域、浑浊羽状流南部边缘;其夏季敏感区主要是近岸海域。悬沙浓度年际变化的幅度略小于季节变化。冬季黄海暖流和台湾暖流对浑浊羽状流的扩散起阻碍作用,二者基本框定了该季节浑浊羽状流的边界范围,其年际变化形成多年尺度上冬季表层悬沙浓度的敏感区。虽然风浪作用对悬沙浓度变化有影响,但不是影响年际变化的主要因素。研究区冬季浑浊羽状流的形成和扩展的变异是受陆架环流控制的,是表层悬沙向深海输运的重要因素。此外,对敏感区的平均海表温度与南方涛动指数(SO)I、太平洋十年涛动指数(PDO)I的相关分析结果表明,本区陆架环流的宏观格局受到了厄尔尼诺-南方涛动(ENSO)和太平洋十年涛动(PDO)的影响,而PDO的影响弱于ENSO。     

琼东和粤西海表温度锋的季节与年际变化特征分析

以2006—2013年卫星遥感海表温度资料(GHRSST SST)为基础,通过数字图像处理的边缘检测方法提取温度锋面的核心位置,分析了琼东、粤西海域海表温度锋位置及强度的季节变化和年际变化特征,并进一步结合海面高度异常资料和海面风场资料探讨了温度锋变化的可能机制。分析结果表明,琼东、粤西海域温度锋的空间分布及锋面强度存在显著的季节变化,沿岸风应力是影响该海域锋面变化的主要动力因素。夏季温度锋面主要分布于琼东沿岸的东部及南部海域近岸50m到100m等深线之间,而冬季则主要分布在琼东的东部海域和粤西沿岸20m到100m等深线之间,春秋两季为其过渡季节;锋面强度的季节变化表现为冬季最强,春季、夏季次之,秋季最弱,其冬季锋面强度平均值可达到3℃?100km–1,夏季为1.7℃?100km–1;同时,锋面核心位置及强度的分析结果表明,琼东和粤西海域温度锋也存在较强的年际变化。     

海州湾岸线变化特征

海州湾位于黄海南部,除北端岚山头,南端连云港一带为基岩海岸外,其余为淤泥质平原海岸。 因区域构造差异,南北岸线变化表现不一,湾顶临洪口是过渡地段。本文着重探讨海州湾全新世特别是近一千年来海面变化特征及     

南黄海西北部夏季潮锋的观测和分析

根据2001-2004年逐年6月多学科综合调查资料和同期NASA的MODIS/Terra卫星遥感SST资料,对南黄海西北部夏季潮锋的不连续分布现象做了分析;并通过三维潮流数值模式计算Simpson-Hunter参数(以下简称S-H参数)分布,对不连续分布的形成机制做了讨论.层化季节南黄海西北部的苏北浅滩-海州湾外侧和山东半岛东部的成山头-石岛外海存在显著潮锋现象,而在两海域之间、青岛以东的山东半岛南部121°~122°E的近岸海域无显著潮锋持续存在;较高分辨率的潮流数值模拟的结果表明潮锋的不连续性分布主要是由潮混合和地形的共同作用而形成.潮锋不连续处海域潮混合较弱,层化现象更为显著.南黄海西北部底层锋形态较为显著,位于通过潮流模式计算的Simpson-Hunter参数1.8~2.4之间,与2.2等值线分布较为一致;表层锋则在海州湾外侧和石岛沿岸海域较为明显.潮锋不连续的分布特征对该海域的生态环境造成一定的影响,叶绿素a、中华哲水蚤、鳀鱼卵子等的数量分布都在潮锋显著的苏北浅滩-海州湾外侧和成山头-石岛外海海域形成较为密集的分布.     

北太平洋副热带中部模态水潜沉区的热收支———个全球海洋模式数据的结果

使用一个全球海洋环流模式的18 a(1993～2010 年)数据, 对北太平洋副热带中部模态水(CMW)潜沉区混合层内热收支的空间分布状况及其季节和年际变率特征进行了分析, 并重点讨论了热收支与太平洋年代际震荡(PDO)之间的相互关联。结果表明, CMW 潜沉区的热收支是海表热力强迫与海洋动力过程之间的平衡。其中混合作用, 特别是湍流扩散是海洋动力过程的主要分量, 对该海区混合层内部的热量耗散起到关键的作用。该海区的热收支具有显著的季节变化信号, 在春夏季与秋冬季存在明显的差异。热收支的年际变化与PDO 的超前滞后相关性分析表明, 该海区的混合层温度(MLT)具有显著的PDO 信号, 同时 PDO 与 MLT 两者随时间的变化信号( ?[P]/?t 与?[T]/?t )之间也有强相关性。?[P]/?t与海表热力强迫项(SEF)显著的相关性表明, SEF 可能会对PDO信号的产生及变化过程产生重要的影响;?[P]/?t 与夹卷项的高相关性则间接证明潜沉的 CMW 的温度存在 PDO 信号; 作为海洋动力过程的主体, 扩散项和平流项均会对PDO 信号变化做出滞后响应。本研究增进了对CMW 潜沉区混合层内海水温度变化特征的认识。     

黑潮延伸体区海平面异常和中尺度涡的时空特征分析

利用1993-2010年间的卫星高度计资料,用EOF方法及小波分析研究了黑潮延伸体区域的海平面异常和中尺度涡的时空变化特征.研究结果表明:海平面EOF第一模态是季节模态,与该海域风应力旋度第一模态类似,相关系数达0.65.EOF第二模态主要反映了黑潮南部次级环流的变化情况,显著性周期是8-10年.通过相关分析发现黑潮延伸体南部次级环流的年代际变化与PDO有关,同时它又与风应力旋度第二模态有关;该海域的海面高度受到北太平洋东部SSH信号西传的影响,信号的传播需要大约3-4年时间.EOF第三模态是黑潮弯曲模态.日本南部的气旋涡和反气旋涡可以表征黑潮弯曲的形成,而且弯曲强度和涡的持续时间、强度和位置有关.     

连云港近岸海域沉积物运移趋势

基于连云港近岸海域夏冬季大面积多站表层沉积物样品的粒度分析结果,采用Gisedtrend粒径趋势分析方法,研究了沉积物的运移趋势,探讨了粒径趋势分析的影响因素,结果表明,连云港近岸海域沉积物运移趋势较显著,在海州湾海域沉积物运移趋势为西南向,表现为湾顶淤积;在港口南部海域沉积物运移趋势显示为汇聚区。特征距离、采样网格、周围环境和粒度组分影响粒径趋势的分析结果;综合考虑岸线、岛屿、人工边界等自然环境以及多源粒度组分能够提高粒径趋势分析结果的合理性。     

南海海表面温度年代际异常变化特征及其与PDO的联系

利用奇异谱分析和小波分析的方法,分析了南海海表面温度异常(SSTA)在年代际尺度上的变化特征及其与太平洋年代际涛动(PDO)之间的关系.发现南海 SSTA 年代际振荡与年循环之间存在一定程度上的锁相:在冬、春季较强,而夏、秋季则较弱.此外,在过去的140多年,南海 SSTA 年代际振荡显著衰弱.通过与 PDO 指数进行相关分析发现,在年代际尺度上 PDO 与南海 SSTA 具有一定的相关性.一方面这种相关性只在20世纪前50年比较显著,这在一定程度上解释了为何南海 SSTA 的年代际振荡表现出衰减的趋势;另一方面,当 PDO 位相超前南海 SSTA 位相3到6个月时,两者表现出较强的相关性.进一步分析表明,PDO 可能通过调控赤道东太平洋 SST,从而影响南海 SSTA 的年代际变化.     

2008 年与2009 年黄海绿潮漂移路径分析

利用卫星资料分析了2008年和2009年黄海绿潮的漂移路径的差异,基于QSCAT(Quick Scatterometer)卫星风场及海洋模式表层环流模拟结果,分析了绿潮漂移路径差异的动力机制。结果表明:2008(2009)年绿潮发生期间黄海海域以南东(偏南)风为主,江苏至山东半岛南岸海域表层平均流为偏北(东北)向,青岛附近海域低频余流为偏西(东)向流,致使绿潮的漂移方向为西北(东北)向,在青岛(烟台-威海)近岸海域发生聚集。2008年和2009年绿潮漂移路径差异,主要由海面风与表层环流的共同作用引起。通过对黄海海域海面风场和表层流场的早期预报,可以提前预判绿潮的影响区域和程度,为政府相关部门防灾减灾工作提供决策支持。     

山东半岛近岸海域蟹类群落结构特征的研究

根据2014年8月和10月、2015年2月和5月使用单船底拖网进行的4个航次调查数据,对山东半岛近岸海区的莱州湾及渤海南部、山东半岛北部和山东半岛南部等3个海域蟹类种类组成、时空分布、优势种、群落结构稳定性等群落结构特征进行了研究。结果显示,4次调查共捕获蟹类20种,隶属于10科17属,其中日本蟳（Charybdis japonica）和三疣梭子蟹（Portunus trituberculatus）是主要经济种类,其余均为小型饵料型蟹类;海区内主要的优势种为双斑蟳（Charybdis bimaculata）、日本蟳（Charybdis japonica）和三疣梭子蟹（Portunus trituberculatus）,3个海域优势种季节更替均十分明显;莱州湾及渤海南部和山东半岛南部2个海域生物量季节变化明显,春季较低,在夏季达到峰值,夏季到冬季呈降低趋势,山东半岛北部海域生物量季节变化不明显。3个海域蟹类群落物种多样性指数（H'）、丰富度指数（D）及均匀度指数（J'）均处于较低水平,并有一定的季节变化;水深、水温和盐度是影响蟹类群落结构的重要因子,渤莱沿岸流、黄海暖流和黄海冷水团通过影响海域内水温与盐度影响蟹类群落结构。研究表明山东半岛近岸海区蟹类以小型饵料型蟹类为主,蟹类多样性水平较低,优势种更替明显,群落季节更替指数较高,季节间迁移频繁,蟹类群落不稳定。     

日本列岛东部海域发现未知海流

日本海洋科学技术中心最近发表观测报告宣布,在日本列岛东部海域发现见了过去未曾观测到的强大海流。 报告说,这股海流的位置在流经日本列岛南部的暖流以北250公里处,由东向西,与暖流呈相反方向,流速达3.5节(1.852公里)每小时。据悉,这股暖流是科学家们于本月初通过观测浮标的位移而发现的。该中心认为这一发现颇有意义,并表示将进一步研究这股海流对渔业资源及二氧化碳吸收量等的影响。     

Plastic litter in the sea

On June 2013 a workshop at the University of Siena (Italy) was organized to review current knowledge and to clarify what is known, and what remains to be investigated, concerning plastic litter in the sea. The content of the workshop was designed to contribute further to the European Marine Strategy Framework Directive (MSFD) following an inaugural workshop in 2012. Here we report a number of statements relevant to policymakers and scientists that was overwhelming agreement from the participants. Many might view this as already providing sufficient grounds for policy action. At the very least, this early warning of the problems that lie ahead should be taken seriously, and serve as a stimulus for further research.     

Biogeochemical studies in the sea

My studies on metabolism of organic matter in aquatic environments first involved research on the sedimentation process of organic matter in lacustrine environments. Subsequently, measurements of primary production in lake and sea water were undertaken to know the organic substance supply into the metabolism. After establishing the routine technique of productivity measurement in aquatic environment, the primary production and the photosynthetic characteristics in waters in the northwestern Pacific, the western Indian Ocean and the Antarctic Sea were studied. Following the development of new methods to determine the organic substances in the dissolved and particulate forms and chlorophyll pigment in seawater, their distributions both horizontal and vertical directions were determined. And I have had interest in the mechanism producing a subsurface chlorophyll maximum in the ocean. Recently, my major interest has been directed to the coastal waters. The nitrogen cycle was studied in oyster beds and the research on eutrophication processes in a shallow bay is being carried out from the aspect of production and decomposition of organic matter.     

Nitrous oxide in the sea

A new gas chromatographic method was developed for the measurement of nitrous oxide (N₂O) in seawater. It takes 15 min for the analysis in a sample of 640 ml seawater.By this method, more than 1000 samples taken over various depths and areas in the sea were analyzed. In the western North Atlantic, the N₂O concentration over a range of oceanic depths gave characteristic profiles that were negatively correlated with oxygen profiles, reaching its maximum (c.a. 1 μg/l) in the oxygen-minimum layer at mid-depths. In the Caribbean, the N₂O maximum reached higher concentrations than in the North Atlantic. N₂O was near equilibrium with that in the atmosphere in Atlantic surface waters, but supersaturation of N₂O was observed in surface waters of the Gulf of St. Lawrence in early June and in most surface samples from the Caribbean Sea in March.The estimated rate of N₂O production in the sea may be significant in terms of geochemical cycling of combined nitrogen to the atmosphere.     

基于ASCAT 散射计数据的2013 年南极周边海面风速特征分析

利用2013年1月1日~2013年12月31日的ASCAT散射计风速数据,从海面风速季平均分布特征、平均海面风速特征、海面风速大于10 m/s发生比例统计等方面,对55°S以南的南极周边海域开展了风速空间分布特性统计,得到以下结果:7月平均风速最大,为12 m/s,1月平均风速最小,为8 m/s。对于南极周边海域,区域平均风速主要在9~12 m/s,全年出现的时间大于280 d,约占全年的77%。风速大于10 m/s所占比例4~9月大于1~3月和10~12月。从全年来看,南极周边海域在4~9月风速普遍较大,且0°~60°W海域内风速明显比其他海域要小。在此基础上将2013年每日的区域平均风速与月平均风速与2012年做了对比,变化趋势与2012年基本一致。通过本项长期工作,可以了解南极风场环境基本情况,建立与更新基础资料和图件,得到南极地区风场要素时空分布、变化规律,服务于南极科学考察、全球变化等多学科研究应用。     

Sedimentary humic substances in the northern Adriatic sea (Mediterranean sea)

Humic compounds were determined in sediments collected in an area of the Adriatic sea receiving fresh waters from the river Po. Sediment cores (10 cm) were sectioned into four layers which were analysed separately for redox potential (Eh), total phosphorus (TP), total organic carbon (TOC), humic (HA) and fulvic acid (FA) content. The structure of HA and FA was also investigated. The results showed that the TOC and TP content decreased from the coast to the open-sea stations. Humic and fulvic acid concentrations were also inversely correlated to the distance from the coast. Moreover, the humic and fulvic acids were closely correlated to the total organic content and to the total phosphorus content. The correlations found between humic substances (HS) and TOC and TP, respectively, could be explained both by an in situ formation due to the high content of nutrients and organic matter, and by a common source of HS, TOC and TP, namely the River Po discharge. The predominant presence of aliphatic carbon in the humic structures, the low degree of substitution and the high nitrogen content suggest that primarily humified compounds were formed in situ. Nevertheless, the River Po can act both as supplier of organic matter of which decomposition products lead to the formation of humic compound and as carrier of humified compounds.     

西沙周边海域海平面异常变化特征及成因分析

Based on the analysis of wind,ocean currents,sea surface temperature(SST) and remote sensing satellite altimeter data,the characteristics and possible causes of sea level anomalies in the Xisha sea area are investigated.The main results are shown as follows:(1) Since 1993,the sea level in the Xisha sea area was obviously higher than normal in 1998,2001,2008,2010 and 2013.Especially,the sea level in 1998 and 2010 was abnormally high,and the sea level in 2010 was 13.2 cm higher than the muti-year mean,which was the highest in the history.In 2010,the sea level in the Xisha sea area had risen 43 cm from June to August,with the strength twice the annual variation range.(2) The sea level in the Xisha sea area was not only affected by the tidal force of the celestial bodies,but also closely related to the quasi 2 a periodic oscillation of tropical western Pacific monsoon and ENSO events.(3)There was a significant negative correlation between sea level in the Xisha sea area and ENSO events.The high sea level anomaly all happened during the developing phase of La Ni?a.They also show significant negative correlations with Ni?o 4 and Ni?o 3.4 indices,and the lag correlation coefficients for 2 months and 3 months are–0.46 and –0.45,respectively.(4) During the early La Ni?a event form June to November in 2010,the anomalous wind field was cyclonic.A strong clockwise vortex was formed for the current in 25 m layer in the Xisha sea area,and the velocity of the current is close to the speed of the Kuroshio near the Luzon Strait.In normal years,there is a "cool eddy".While in 2010,from July to August,the SST in the area was 2–3°C higher than that of the same period in the history.     

Inorganic nitrogen metabolism in the sea

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Inorganic nitrogen metabolism in the sea

     

Benthic storms in the Greenland sea

We present observations of strong, episodic, bottom-intensified currents from two current meter moorings, each of a year's duration, placed in the central Greenland Sea at 75°N, 8°W, in a water depth of circa 3340 m. The events, recorded by the current meters placed some 50 m above the sea floor, occur about 4 times a year and last about a week. They show currents of up to 43 cm/s, turning in direction, occasionally modulated by a signal of the frequency of the Coriolis parameter or the semi-diurnal tide. The temperature record at the current meter however remains constant to 0.01°C. The current direction measured at overlying meters correlates well with that of the deepest meter – the current speed does not. Independent, geological data also show evidence of strong bottom flows in the area.We discuss possible mechanisms for these `benthic storms', including the hypothesis of a sediment driven plume descending from the East Greenland continental slope. These high energy events have implications for sedimentation, shelf-basin exchange and boundary mixing processes. Normal mode theory is used to justify the dynamical response of the system to such a bottom-trapped impulse.