The Effect of the East China Sea Kuroshio Front on the Marine Atmospheric Boundary Layer

Various satellite data,JRA-25(Japan reanalysis of 25 years) reanalyzed data and WRF(Weather Research Forecast) model are used to investigate the in situ effect of the ESKF(East China Sea Kuroshio Front) on the MABL(marine atmospheric boundary layer).The intensity of the ESKF is most robust from January to April in its annual cycle.The local strong surface northerly/northeasterly winds are observed right over the ESKF in January and in April and the wind speeds decrease upward in the MABL.The thermal wind effect that is derived from the baroclinic MABL forced by the strong SST gradient contributes to the strong surface winds to a large degree.The convergence zone existing along the warm flank of the ESKF is stronger in April than in January corresponding to the steeper SST(sea surface temperature) gradient.The collocations of the cloud cover maximum and precipitation maximum are basically consistent with the convergence zone of the wind field.The clouds develop higher(lower) in the warm(cold) flank of the ESKF due to the less(more) stable stratification in the MABL.The lowest clouds are observed in April on the cold flank of the ESKF and over the Yellow Sea due to the existence of the pronounced temperature inversion.The numerical experiments with smoothed SST are consistent with the results from the ovservations.

Barrier and compensation layers in the East China Sea

Climatology of the isothermal layer depth （ILD） and the mixed layer depth （MLD） has been produced from in-situ temperaturesalinity observations in the East China Sea （ECS） since 1925. The methods applied on the global are used to compute the ILD and the MLD in the ECS with a temperature criterion AT=0. 8 ℃ for the ILD, and a density criterion with a threshold △σθ corresponding to fixed △T=0. 8 ℃ for the MLD, respectively. With the derived climatology ILD and MLD, the monthly variations of the barrier layer （BL） and the compensation layer （CL） in the ECS are analyzed. The BL mainly exists in the shallow water region of the ECS during April-June with thickness larger than 15 m. From December to next March, the area along the shelf break from northeast of Taiwan Island to the northeast ECS is characterized by the CL. Two kinds of main temperature - salinity structures of the CL in this area are given.

Tide-Induced Mixing in the Bottom Boundary Layer in the Western East China Sea

The East China Sea(ECS)boasts a vast continental shelf,where strong tidal motions play an important role in the substance transport and energy budget.In this study,the tide-induced mixing in the bottom boundary layer in the western ECS is analyzed based on records measured by moored acoustic Doppler current profilers from June to October 2014.Results show that the M_(2) tide is strong and shows a barotropic feature,whereas the O_(1) tide is much weaker.Based on the M_(2) tidal currents,the eddy viscosity in the bottom Ekman boundary layer is estimated with three schemes.The estimated eddy viscosity values vary within 10^(-4)–10^(-2)m^(2) s^(−1),reaching a maximum at approximately 5 m height from the bottom and decreasing exponentially with the height at all three stations.Moreover,the shear production of turbulent kinetic energy is calculated to quantify the mixing induced by different tidal constituents.The results show that the shear production of the M_(2) tide is much stronger than that of the O_(1) tide and shows a bottom intensified feature.

Current measurements and spectral analyses in the upper 450 m and deep layers of the northeastern South China Sea

On the basis of the current measurements from the moored Long Ranger ADCP in the upper 450 m layer and the deep current measurements at 2000 and 2300 m from the moored current meters with the time series data of about 7 months at the mooring station in the northeastern South China Sea, the spectral analyses and calculation have been made. The major results are as follows: (i) From the progressive vector diagrams of the observed daily currents at the water levels from 50 m to 400 m, its temporal variation of velocity rotated counterclockwise in most of the observing time. This agrees basically with the result from the qualitative analysis of the sea surface height data, which was obtained from TOPEX/ERS-2 altimeter data by CCAR. The daily and monthly average velocities are both the largest in November, next in October and minimum in August. (ii) At the 2000 and 2300 m levels, the daily and monthly average velocities are both the largest in January, next in September and minimum in August. From the seasonal change of currents, the current velocity is the strongest in winter (January-March), next in autumn, and weak in summer. (iii) There exists the variation of tidal current with the change of depth. In the upper layer, the height of diurnal peak is higher than that of semidiurnal peak. However, the semidiurnal peak is higher than the diurnal peak at the levels from 200 m to 400 m. In the layers above 450 m the clockwise component is dominant in their fluctuations. In the layers below 1500 m the diurnal peak is again higher than the semidiurnal peak. (iv) There is the prominent periodic fluctuation of more than two months in the layer from 50 m to 2300 m. The period of this prominent peak is 75 d and its fluctuation is counterclockwise in the upper 450 m layers, and is 68 d and 69 d at the depths of 2000 and 2300 m, respectively, and the counterclockwise component is dominant in their fluctuations. (v) There are the variations of periods fluctuating with the change of depth in the upper 450 m layers. For example, when f>0, there are the prominent fluctuations of about 22 d and 15 d period at the 50 and 100 m levels. However, there are no such periods at the layer from 200 m to 400 m, where only the fluctuation of about 13 d period occurs. (vi) There are the fluctuations with periods of more than one month, 23 d and 15 d at the 2000 m and 2300 m levels. (vii) In the layer from 50 m to 2300 m there are the following prominent peaks: i) the fluctuation in the period range of about 4-8 d, which occurs in the weather process; ii) the fluctuation with inertial period, the fluctuation is clockwise; and iii) the fluctuations with short periods of about 8 h and 6 h. (viii) From the cross spectral estimates between two time series, it is shown that there are significant coherence peaks with the periods of more than two months(T = 68.3 d) and more than one month between the two time series of currents at 2000 m and 2300 m depths, and also those with periods of about half a month (15.5 d), 2 d and so on between two time series of currents at 100 m and 2300 m depths.

Parameterization Method of Wind Drift Factor Based on Deep Learning in the Oil Spill Model

Oil spill prediction is critical for reducing the detrimental impact of oil spills on marine ecosystems,and the wind strong-ly influences the performance of oil spill models.However,the wind drift factor is assumed to be constant or parameterized by linear regression and other methods in existing studies,which may limit the accuracy of the oil spill simulation.A parameterization method for wind drift factor(PMOWDF)based on deep learning,which can effectively extract the time-varying characteristics on a regional scale,is proposed in this paper.The method was adopted to forecast the oil spill in the East China Sea.The discrepancies between predicted positions and actual measurement locations of the drifters are obtained using seasonal statistical analysis.Results reveal that PMOWDF can improve the accuracy of oil spill simulation compared with the traditional method.Furthermore,the parameteriza-tion method is validated with satellite observations of the Sanchi oil spill in 2018.

Evolution of the South China Sea and monsoon history revealed in deep-sea records

As the third summary report of ODP Leg 184 to the South China Sea (SCS), this paper discusses the evolution of the East Asian monsoon and the SCS basin. A multi-proxy approach, involving geochemistry, micropaleontology, pollen and other analyses, was adopted for reconstructing the evolutionary history of the East Asian monsoon, which was characterized by a series of paleo-climate events especially at 8, 3.2, 2.2 and 0.4 Ma. The new record indicates similar stages in the development of the East and South Asian monsoons, with an enhanced winter monsoon over East Asia being the major difference. The rich spectrums of monsoon variability from the southern SCS also reveal other characteristic features of the low latitude ocean. Evidence for the evolution of the SCS includes the hemipelagic Oligocene sediments, implying the existence of deep water environments during the early seafloor spreading stage of the SCS basin. The four major unconformities and some remarkable diagenetic features in upper Oligocene deposits indicate the strongest tectonic events in the region. From a careful comparison of lithologies and sedimentation rates, we conclude that the prominent differences in sedimentary environments between the southern and northern SCS were established only by ～3 Ma.

Coastal seafloor observatory at Xiaoqushan in the East China Sea

The seafloor observation system is becoming an important infrastructure for marine research because it is transforming oceanic research from temporal investigation to long term observation.The East China Sea coastal seafloor observatory,located between 30°31′44″N,122°15′12″E and 30°31′34″N,122°14′40″E,is constructed near the Xiaoqushan Island outside the Hangzhou Bay on the inner continental shelf of the East China Sea.The observatory is connected by a submarine optical fiber composite power cable that is more than one kilometer long and consists of a special junction box that transmits power and communication signals to different instruments.The special junction box has a variety of waterproof plugs and connects to three different instruments installed in a trawl preventer.The submarine optical fiber composite power cable is landed on the platform by The East China Sea Branch,State Oceanic Administration and the power is continuously supplied by the solar panels and solar battery on the top of the platform.The real time data are directly sent through the cable to the platform and are transmitted by CDMA wireless to the receiver at the State Key Laboratory of Marine Geology of Tongji University.Measurements at the observatory have been taken since April 20,2009 after installation and the results have been interpreted.The characteristics of the near bottom boundary are constrained by a sediment suspension model using portion of the observed data.In particular,discussion is provided on the sea surface height anomaly at Xiaoqushan Island influenced by the tsunami driven by the 2010 Earthquake in Chile.The successful establishment of the coastal seafloor observatory is the first step toward future development of seafloor observation systems in China.It not only accumulates experiences in technology and engineering,but also paves the way for performing important oceanic research using the long term continuous observation platform.

Deep-sea pollen research in China

This paper briefly presents the progress of deep-sea pollen research in China since the beginning of ninetieths of the last Century. All the deep-sea pollen contri- butions mainly come from the South China Sea (SCS) and the East China Sea (ECS). The German-Chinese joint cruise (Sonne 95) and ODP 184 cruise initiated by Chinese scientists in the SCS provided excellent material for the deep-sea pol- len research. So far a number of pollen results of 20—30 ka and million years from the SCS have been published. A couple of deep-sea pollen records from Okinawa Through of the ECS also came out. The high resolution pollen records obtained from the continuous deposits with high sedimentation rates and reliable age control of the deep-sea sediments provided a high time resolution history (hundred to millennial scales) of vegetation, environment and monsoon evolution of the pollen source areas (southern China and Japan). Spectral analysis of deep-sea pollen records from the SCS discovered orbital (100, 41, 23, 10 ka) and suborbital cyclicities (Heinrich and Dansgaard/Oscheger-O/D events) in the vegetation changes. Moreover, cross spectral analysis showed that the trend of vegetation changes in northern SCS was regulated mainly by changes of the ice volume in the Northern Hemisphere. The pollen record of the last 20 ka from the Okinawa Through of the ECS indicates that the marine environmental change lagged that on the terrestrail by about 1000 year. The asynchronous environmental changes between land and sea were probably caused by the time difference in thermohaline circulation. This study underscored the role of the deep-sea plant fossils as a bridge across the land and sea.

Characterization of Fe-S minerals influenced by buried ancient woods in the intertidal zone,East China Sea

An ancient wood layer dated at about 5600 cal. a BP by AMS14C dating was discovered in the intertidal zone, East China Sea. Samples affected by ancient woods, including fresh coast bedrock, weathering bedrock, seepage water from coast, seepage water from ancient wood layer, intertidal seawater, fresh water, beach mud, ancient wood barks and ancient peat, were collected for geochemical analysis. The beach mud and the bacteriogenic iron oxides (BIOS) in coastal seepage water were analyzed by min-eralogical and high-resolution transmission electron microscopy (HRTEM)-selected area electron dif-fraction (SAED) analysis. Inorganic sulfur compositions and δ34S of the ancient peat and the beach mud were determined. The results showed that Fe, Mn, S (SO42-) were enriched in the intertidal area at different levels, very likely caused by fermentation of ancient woods. The presence of abundant iron-oxidizing bacteria (FeOB) and sulfate-reducing bacteria (SRB) in this intertidal zone was confirmed by HRTEM-SAED observation, and these bacteria were involved in Fe-S cycle to induce extracellular biomineralization. The negative δ34SV-CDT (-2.9‰) likely indicated the biogenic origin of iron-sulfide minerals in the beach mud at high sulfate reduction rate (SRR). These findings are helpful for under-standing the biogeochemical Fe-S cycle and biomineralization process at high organic matter deposition rate and high SRR in the intertidal zone, estuary, or near shoreline.

西湖凹陷木广迎地区断陷层地质结构与油气勘探意义

西湖凹陷是东海陆架盆地内规模最大的富油气凹陷,保俶斜坡带是凹陷内油气勘探的主要地区。近期勘探实践表明,斜坡带深层构造—岩性领域具有良好的勘探前景。开展斜坡带北部木广迎地区深部断陷层地质结构与油气勘探潜力分析,对于明确西湖凹陷构造—岩性领域下步有利突破方向具有重要意义。本文综合利用高精度三维地震和钻井资料,开展木广迎地区精细的构造和层位解释。根据解释结果进行埋藏史—热演化史模拟,并系统分析区内油气地质条件。研究表明,木广迎构造带整体表现为东倾斜坡,北部发育古新统厚度中心;区内发育走向为NE、NNE和NW向的3组断裂,多数断裂的主活动时期为古新世—始新世,活动强度逐渐减弱;木广迎地区现今古新统残留厚度为200~1500 m,暗色泥岩厚度为100~700 m,最厚可达700 m以上,其主体于宝石组沉积时期进入成熟阶段;宝石组内发育大套厚层砂岩,且物性较好,可作为有利储层。研究认为,木广迎地区发育良好的生—储—盖组合和有效的源—储配置,是西湖凹陷斜坡带构造—岩性领域勘探的有利方向。

东海盆地西湖凹陷平湖斜坡始新统平湖组成岩相类型及对储层的控制

为了在深埋藏、强非均质性背景下寻找相对优质储层,本文以东海盆地西湖凹陷平湖组为例,基于直观微区观测、间接压汞表征及孔渗分析相结合的方法,在储层沉积学分析的基础上,先划分成岩相类型,进而明确不同成岩相的差异储集能力特征,评价成岩相储集能力。结果表明:平湖组沉积于河流和潮汐双向水动力条件的三角洲-潮坪体系,砂体多发育于水下分流河道、河口坝、潮道、砂坪和混合坪中,以细粒和极细粒为主,主要为长石岩屑砂岩和岩屑长石砂岩;基于成岩作用类型的强度差异将成岩相划分为3类,包括长石溶蚀相、富塑性压实相和钙质胶结相;同一成岩相类型孔渗特征和孔隙结构特征均一,而不同成岩相之间物性差异显著;以孔隙度、渗透率、最大连通孔喉半径为标准对3类成岩相进行量化参数分级评价,长石溶蚀相孔隙度>15%,渗透率>10.0×10^(-3)μm^(2),最大连通孔喉半径>5.0μm,物性条件优于富塑性压实相和钙质胶结相,优选出长石溶蚀相为最有利的储层砂体类型。

南海东北部海陆深地震联测与滨海断裂带两侧地壳结构分析

南海东北部首次成功实施海陆联合深地震探测 ,填补了海陆过渡带深地震探测的空白 .利用该次海陆联测地震数据 ,通过数据处理、震相分析、射线追踪、走时模拟等方法 ,获得了滨海断裂带附近的纵波地壳速度结构 ,探明了海陆联测剖面中滨海断裂带可能位置 .地壳速度结构为陆壳结构 ,地壳厚度由陆地向海区逐步变薄 ;在上地壳下部普遍存在一层速度为 5 .5～ 5 .9km·s-1、厚度为 2 .5～ 4 .0km的低速层 ,并向海区方向减薄 ,该区未发现明显的高速层 .滨海断裂带为一纵向低速带 ,位于南澳台东南 35km处 ,对应于重、磁异常带 ,断裂带断至莫霍面 ,是华南陆区正常型陆壳与海区减薄型陆壳的分界地壳断裂 .

东海区七星底灯鱼数量分布以及与温盐度的关系

本文利用从2000年12月列2001年9月一个周年的渔业资源调查数据，对东海区七星底灯鱼的数量分布及其与温盐度的关系进行了研究。结果表明：东海区的七星底灯鱼可分为东海北部和浙江中南部近海2个群体。以东海北部群体较大，主要分布在30°N以北的海域；浙江中南部近海群体较小，且只有零星分布。七星底灯鱼在东海北部海域从沿岸到外海都有分布，但沿岸数量较少，主要分布在30°30′～32°30′N、124°00′～126°30′E之间的海域；以冬春季竹分布面较广，夏秋季节的分布面较窄：东海北部群七星底灯鱼柄息海域的表层温度值变化较大，以春季最低，秋季最高；密集分布区的等温线变化范围在1～2℃左右。浙江中南部近海群的栖息水温变化较小，全年都在20℃以上。各季节浙江中南部近海群的适宜水温均高于东海北部群。各季节尔海北部群密集分布区的表层盐度在32.0～34．5之间，以冬春季的盐度值较高，夏秋季的盐度值较低；浙江中南部近海群的柄息海域表层盐度除冬季较高外，其余季节相对较低。

中国东部陆架沉积环境对末次冰盛期以来海面阶段性上升的响应

到目前,还缺乏关于大型陆架系统对全球海面变化响应的研究,5年来我们对中国东部宽阔的陆架海底进行详细制图研究,结果表明:现代中国东部陆架海底沉积环境分布与末次冰盛期以来的海面变化之间有很好的响应关系;目前的陆架海底被3个沉积体系覆盖,即低海面期的古滨带、冰消期的海侵体系和高海面期的涡漩及近岸带沉积体系;末次冰期后期以来,可区分出3个快速海面上升期和3个慢速上升期。在快速上升期,海底形成了代表海岸快速移动的混杂沉积-海侵边界层,海岸平均移动速度10～22cm/a(最大64cm/a),缓慢上升期,形成了陆架广泛分布的潮流沙脊体系,三期沙脊体系之间有继承性演化关系。

东海北部秋季小黄鱼分布特征及其与底层温度和盐度的关系

根据2003-2006年每年秋季（9月下旬）在东海北部的渔业资源和温盐度同步调查资料,对小黄鱼（Larimichthys polyactis）和底层温盐度的分布特征进行了研究,并对它们的关系进行探讨。结果表明,东海北部秋季小黄鱼主要分布在大沙、长江口和江外水域。小黄鱼索饵群体主要出现在暖水控制区及其边缘水域：暖水区底层水温22-25℃,底层盐度31.5-33.0;暖水边缘区底层水温14-21℃,底层盐度33.0-34.0。长江口水域是当年生索饵群的主要出现水域,呈高温低盐特征;江外、舟外、沙外水域是隔年生索饵群体的主要出现水域,为低温高盐特征;混合索饵群主要出现在水温和盐度均偏低的南黄海和大沙水域。长江冲淡水和东海暖水势力较强的年份,小黄鱼的分布面较广且CPUE值较高;长江冲淡水中心水温高于25℃的年份,小黄鱼在其影响范围内出现率较高;在黄海冷水团控制的南黄海水域,水温和盐度偏低的年份,小黄鱼的CPUE值也较低。东海北部秋季小黄鱼当年生群体主要在长江冲淡水控制的高温低盐的近海海域索饵;隔年生群体由于对环境的适应性较强,主要在低温高盐的外海水域进行索饵。

南海深海声学散射层垂直分布和昼夜变化初步研究

2013-09利用船载Simrad EK60科学鱼探仪（38kHz）对南海深海声学散射层进行了连续监测,并结合变水层拖网采样分析了其垂直分布和昼夜变化。结果表明,南海深海存在2个明显的声学散射层,特征深度分别为0-100m和350-700m,并且2个散射层间存在较为明显的昼夜垂直移动现象。其随时间变化情况为：16∶00-19∶00,350-700m散射层中的部分生物逐渐向上移动到0-100m散射层;04∶00-07∶00,这部分上升的生物又逐渐移回至350-700m散射层。变水层拖网采样结果发现,白天0-100m散射层内渔获物数量较少,夜间0-100m散射层内渔获物较多,验证了声学映像所检测到的2个散射层间确实存在昼夜移动的现象。

东海盆地西湖凹陷深部储层“相-岩-温”三元分级评价原则与效果

西湖凹陷是东海盆地最有油气潜力、最有勘探难度的沉积盆地,储层类型多样且致密化严重是目前制约资源评价的重点难题之一。现有的储层评价标准并没有充分考虑到多样性储层并存的特征,对于储层的评价依然依托的是常规储层评价标准,并没有系统开展过多类型储层的分类、分级评价。在充分讨论西湖凹陷储层控制因素的基础上,遴选出储层发育的主要控制要素,建立了“微相-成岩-温度”三要素联控下的储层三元分级方案,并在此基础上,对主要目的段储层开展了分级评价,认为花港组储层以低渗特低渗储层为主,占总储层的35%以上,是未来主要的勘探类型。平湖组以常规和低渗储层为主。研究成果为后期资源量分级评价奠定了基础,也为国内外同类型盆地储层评价提供了借鉴。

我国东海陆架地区新生代地层的热导率

对东海陆架区的浅表层柱状岩芯样品和多口钻井岩心样品的热导率数据按岩性、深度、年龄和孔隙度进行了统计分析。发现泥岩、粉砂岩和砂岩的热导率有所不同。在 3 0 0 0m以上 ,泥岩的热导率大于砂岩的热导率 ;而在 3 0 0 0m以下砂岩的热导率则大于泥岩的热导率。粉砂岩的热导率基本介于泥岩和砂岩之间。岩石的热导率和岩石样品所处的深度密切相关 ,随着深度的增大热导率数值增大。岩石的年龄影响岩石的热导率。在同等深度的情况下 ,年龄越老 ,热导率数值越高 ,但埋深浅的老地层热导率会小于埋深大的新地层的热导率。孔隙度和含水对岩石样品的热导率有很大的影响 ,岩石会因孔隙中含水而使热导率有非常大的变化。

南黄海南部与东海北部之间的深部构造

针对南黄海南部与东海之间的深部构造 ,根据前一段地球物理研究的结果 ,与有关文献进行对比探讨 ,发现其差异 .在重力和三维地震层析成像结果基础上 ,探讨分析了该海域的深部构造 ,给出分布在南黄海南部与东海北部之间的苏浙—济州岛构造带的分布位置、形态特征 ,并讨论了该构造带的性质、与周边构造体系和构造演化的关系 ,并指出这一构造由于朝鲜半岛西缘断裂带的存在而并未延伸进入朝鲜半岛 .

西湖凹陷深层低渗-致密气藏“甜点”类型划分及成因探讨

低渗-致密气藏开发的关键是"甜点"的识别和预测,为探索海上少井、深层低渗-致密气藏"甜点"类型及成因,指导油气田勘探开发,利用岩心观察,铸体、阴极发光、扫描电镜等薄片鉴定,粒度分析,核磁共振,高压压汞,恒速压汞,孔渗测试和元素分析等多种手段对东海陆架盆地西湖凹陷X气田"甜点"进行研究。首先对研究区"甜点"定义进行探讨,并根据理论产能、物性、孔隙结构和束缚水含量将"甜点"分为3类:Ⅰ类"甜点"为高产气藏,以Ⅰ类孔隙结构为主,束缚水饱和度大多处于22%~57%;Ⅱ类"甜点"为中产气藏,储层中主要发育Ⅱ类孔隙结构,其次为Ⅰ类孔隙结构,少见Ⅲ类孔隙结构,束缚水饱和度大多处于45%~55%;Ⅲ类"甜点"为低产气藏,主要以Ⅲ类孔隙结构为主,发育少量Ⅳ类孔隙结构,束缚水饱和度大多处于45%~55%。认为Ⅰ类和Ⅱ类"甜点"能够实现现阶段经济有效开发,Ⅲ类"甜点"为后期开发的"潜力层"。研究认为,埋深是控制"甜点"发育的决定性因素,研究区4000 m以深基本不发育Ⅰ类和Ⅱ类"甜点";沉积环境是控制"甜点"发育的内因;事件性沉积作用及成岩作用是Ⅰ类和Ⅱ类"甜点"的重要影响因素;溶蚀作用是Ⅲ类"甜点"的主控因素;构造运动是研究区气藏"甜点"形成和保存的必要条件。