南海混合层近惯性能通量的时空变化

On the basis of the QSCAT/NCEP blended wind data and simple ocean data assimilation(SODA), the wind-induced near-inertial energy flux(NIEF) in the mixed layer of the South China Sea(SCS) is estimated by a slab model, and the model results are verified by observational data near the Xisha Islands in the SCS. Then, the spatial and temporal variations of the NIEF in the SCS are analyzed. It is found that, the monthly mean NIEF exhibits obvious spatial and temporal variabilities, i.e., it is large west of Luzon Island all the year, east of the Indo-China Peninsula all the year except in spring, and in the northern SCS from May to September. The large monthly mean NIEF in the first two zones may be affected by the large local wind stress curl whilst that in the last zone is probably due to the shallow mixed layer depth. Moreover, the monthly mean NIEF is relatively large in summer and autumn due to the passage of typhoons. The spatial mean NIEF in the mixed layer of the SCS is estimated to be about 1.25 m W/m2 and the total wind energy input from wind is approximately 4.4 GW. Furthermore, the interannual variability of the spatial monthly mean NIEF and the Ni?o3.4 index are negatively correlated.     

南海北部台风和中尺度暖涡对近惯性振荡的影响

基于2014年8-9月南海北部东沙群岛附近海域两个临近站位(站位A,20.736°N,117.745°E,水深1 249 m;站位B,20.835°N,117.56°E,水深848 m)的潜标数据,研究了台风过境所激发的近惯性振荡的特征,分析了中尺度暖涡对近惯性频率的调制及其对近惯性动能分布和传播的影响。站位A(B)142(175) m以浅,近惯性频率由0.710 1(0.713 3)周/d红移至0.659 2周/d,频率减小了7.2%(7.6%),观测结果与两个站位所处的背景涡度相吻合。中尺度暖涡改变了水体层结状态,两个站位的近惯性动能在不同层结中被改变了0.5～3倍。水体层结对能量的折射作用使得站位B的近惯性动能在深度158～223 m之间衰减较少,而站位A的近惯性动能则随着深度的增加快速减小。站位A和站位B近惯性内波的垂向群速度分别约为15.2 m/d和14.1 m/d。如果忽略近惯性动能的水平辐散,近惯性内波的垂向传播分别造成了两个站位垂向上约47%和38%的近惯性动能衰减。     

基于实测资料的南海北部台风“海鸥”致近惯性振荡研究

文章利用2014年9月南海东北部附近海域的A、B两个相距约20km的潜标数据, 分析了台风“海鸥”在南海东北部激发的近惯性振荡的垂向分布特征。结果表明, 台风过境在两站点激发了强烈的近惯性振荡, 其能量由海表向海洋内部传播; 近惯性能量在表层随着深度增加而增大, 最大值出现在次表层, 此后随着深度增加迅速衰减。但是两个观测站点的近惯性振荡垂向分布特征有较大的差别: A站点的近惯性振荡在不同深度上存在三个不同的垂向相速度, 而B站点的垂向相速度没有变化; 两站点的最大近惯性动能的大小及其所在深度不同, B站点比A站点的最大近惯性动能大15%左右。台风过后两个站点均出现由近惯性波f和半日内潮波D₂非线性相互作用产生的次级波动fD₂, 但其强度存在差异。台风后A站点fD₂在不同深度上有不同的变化, f和D₂相互作用较弱; 而B站点的fD₂在整个近惯性振荡影响深度内都是增强, 其fD₂和f频带的动能和流速在时空分布以及变化趋势上有较好的相关性。两站点的近惯性振荡垂向相速度以及次级波动fD₂的不同可能是水体层结的差异和涡旋的影响所导致的。     

南海北部流切变环境中台风引起的近惯性振荡的比较研究

通过2008年和2009年布放在南海北部的声学多普勒流速剖面仪(ADCP)锚系潜标,本文观测到了三次由台风引起的近惯性振荡(NIO)事件,分别编号为2008a,2009a,2009b,并对其进行了比较研究.其中2008a在三次事件中强度最大,持续时间最长(15 d),而2009a和2009b仅分别持续了4 d和8 d.三次事件的垂直能量分布和位相传播有明显的区别.在频率偏移方面,2008a的峰值频率略低于局地科氏频率(红移),而2009a和2009b则体现出蓝移.不同的NIO事件的特征表现主要由台风扰动和背景流场环境共同决定,特别是背景流场通过平流和调制作用在其中起了重要的作用.本文的研究为不同背景流场中NIO的不同响应提供了观测的证据.通过分析数模提供的背景流场的涡度和有效科氏频率,2008a事件中较强的振幅和较长的持续时间是由于背景的剪切流场的波导效应造成,其改变了台风过后NIO的能量分布,将入射波能量集中于负涡度区域.而2009a和2009b事件中由于涡度不明显,因此没有类似效应.     

南海西北陆坡区内潮与近惯性内波观测研究

通过对2006年南海西北部海域近3个月的全水深流速观测资料的分析,研究了该海区正压潮、内潮及近惯性内波的时空分布特征。结果表明,全日内潮明显强于半日内潮,且最大潮流均出现在海洋上层;内潮的主轴方向基本沿东南-西北方向,近似与局地等深线垂直;内潮能量显示出明显的时间长度约为半月的大小潮调制周期;全日内潮的coherent部分占全日内潮能量的70%,而半日内潮的coherent部分占半日内潮能量的53%;进一步研究发现半日内潮主要由第一模态主导,而全日内潮第三模态能量占总能量的比例仅次于第一模态且量值上与之相当;强风过程可激发出强的近惯性运动,暖涡使得近惯性内波能量更有效地向海洋深层传播,冷涡则不利于近惯性内波能量向下传播。     

Spatio-temporal variability in sea surface wind stress near and off the east coast of Korea

Sea surface wind stress variabilities near and off the east coast of Korea, are examined using 7 kinds of wind datasets from measurements at 2 coastal (land) stations and 2 ocean buoys,satellite scatterometer (QuikSCAT), and global reanalyzed products (ECMWF,NOGAPS,and NCEP/NCAR). Temporal variabilities are analyzed at 3 frequency bands; synoptic (2-20 d), intra-seasonal (20-90 d),and seasonal (>90 d).Synoptic and intra-seasonal     

山东半岛东部近岸表层沉积物放射性核素的季节性变化及其环境指示意义

基于2019年4月、7月、10月、12月渤黄海共享航次取得山东半岛东部近岸H01和H02站位多个季节沉积物样品,通过低本底γ能谱仪分析得到其表层沉积物放射性核素7Be、210Pbex、228Thex和 137Cs活度数据。结果表明,短半衰期核素7Be、228Thex与长半衰期核素210Pbex、137Cs在同一站位的季节分布存在差异,同一核素在H01和H02站位的季节分布也存在差异;H01站位的7Be和228Thex,H02站位的210Pbex和137Cs,受表层沉积物粒度影响较不明显,7Be和228Thex的季节变化受悬浮物质的输运和沉降的影响显著,而210Pbex和137Cs更多指示的是环流作用下的沉积物再分配;与H02相比,H01站位表层沉积物核素变化受大气沉降影响较低。H01和H02站位分别位于“Ω”形泥质体顶部和东部边缘,其物源和沉积动力环境存在差异,放射性核素7Be、210Pbex、228Thex和137Cs在示踪物质输运和沉降过程中具有重要意义。     

莱州湾东岸近岸海域规划围填海后冲淤演变预测

运用Mike21模型中的水动力模块对研究区的潮流场进行了模拟,分析研究区的冲淤趋势;利用经验公式,对波浪和潮流进行耦合,计算出极端条件下的最大冲刷深度,对比规划用海实施前后的最大冲刷深度,以对该区域的海岸防护、工程选址等提供科学依据。结果表明:受到填海工程的影响,龙口湾内有轻微淤积,界河至石虎咀近岸海域的波浪和潮流受工程影响而变小,冲刷强度变弱。     

莱州湾东岸海底地下水来源判别及量值估算

采用稳定同位素——¹⁸O、D, 结合常规离子分析结果确定了莱州湾东岸海底地下水的来源, 并采用数值方法估算了其量值。结果表明: 莱州湾东岸海底地下水主要来源于波浪、潮汐的海水补给, 同时在一定程度上受地下水径流排泄的影响, 三者对海底地下水的贡献率分别为 31.0%, 56.3%和 12.7%。研究结果对于合理开发、科学保护海底地下水具有重要现实意义。     

基于观测的南海越南沿岸次表层涡旋

In this study, subsurface eddies near the Vietnam coast of the South China Sea were observed with in situ observations, including Argo, CTD, XBT and some processed and quality controlled data. Based on temperature profiles from four Argo floats near the coast of Vietnam, a subsurface warm eddy was identified in spring and summer. The multi-year Argo and Global Temperature and Salinity Profile Programme(GTSPP) data were merged on a seasonal basis based on the data interpolating variational analysis(DIVA) method to reconstruct the three-dimensional temperature structure. There is a warm eddy in the central subsurface at 12.5°N, 111°E below300 m depth in spring, which does not exist in autumn and is weak in winter and summer. From CSIRO Atlas of Regional Seas(CARS) and Generalized Digital Environment Model(GDEM) reanalysis data, this subsurface warm eddy is also verified in spring.     

山东半岛北岸跨锋面物质输运对辽东半岛东岸沉积有机质含量及来源的影响

深入理解气候变化影响下海洋动力过程变化及其多重环境效应,是了解海岸海洋系统未来演化趋势的重要途径。因此,本文在辽东半岛东岸泥质区取柱状样一根,通过沉积物粒度、TOC/TN含量、δ13C以及δ15N等指标,分析气候变化下山东半岛北岸跨锋面物质输运强度变化,及其对辽东半岛东岸泥质区沉积有机质含量和来源的影响。结果表明,高海面时期以来,山东半岛北岸跨锋面物质输运可分为两个变化阶段：6.5～2.9 cal ka BP,其强度随冬季风和黄海暖流的不断减弱而减弱;2.9 cal ka BP至今,由于冬季风较弱而黄海暖流总体强盛,其强度随黄海暖流的波动而呈现4段式的复杂变化。此外,辽东半岛东岸泥质区陆源和海源有机质含量与其强度呈正相关,相应于跨锋面物质输运强度的变化,6.5～2.9 cal ka BP期间,陆源和海源有机质含量持续减少,而2.9 cal ka BP至今则呈现复杂的4段式变化。总体上看,自6.5 cal ka BP以来,陆源有机质贡献率不断下降而海源有机质贡献率逐渐上升。     

Numerical Experiments of the Influences of the Transport Variation through the Korea Strait on the Japan/East Sea Upper Layer Circulation

Numerical experiments were performed in order to investigate the effects of variations of the transport through the Korea/Tsushima Strait, an inlet of the Japan/East Sea, on the upper layer circulation in the JES based on a 10-month transport observation from May 1999 to March 2000 (Perkins et al., 2000). All external forcings to the model were annual mean fields, except the transport variation through the Korea Strait. In the experiments where the periodic variation of the transport repeated continuously sinusoidally by several periods, strong variability of sea surface height (SSH) was detected in the region extending from the Korea Strait to the Japanese coast due to the geostrophy of the buoyancy forcing at the Korea Strait. The region along the Korean coast is more sensitive to the long-term variations than the short-term (≤60-day period) ones. In two experiments forced by realistic and monthly mean transport, the difference of rms of sea surface height was largest at the Japanese coast and relatively large at the East Korean Warm Current separation region (128∼130°E, 39∼41°N) and to the east of Yamato Rise. The distribution of difference of eddy kinetic energy at 100 m depth between the two experiments was similar to that of the rms of SSH. In the distributions of mean SSH and mean kinetic energy at 100 m depth the realistic transport invokes eddy variability to interact with mean current resulting in the changes of the mean SSH and the mean kinetic energy at the East Korean Warm Current separation region, but it does not produce conspicuous changes in the mean fields of entire JES compared with the mean fields forced by the seasonal transport.     

Temperature variability caused by internal tides in the coastal waters of east coast of Peninsular Malaysia

The effects of tidal currents (i.e., barotropic and internal tides) are important in the biogeochemistry of a coastal shelf sea. The high-frequency of currents and near-bottom temperatures collected in three consecutive southwest monsoon seasons (May, June, July and August of 2013 until 2015) is presented to reveal the role of the tidal currents to the temperature variability in the coastal shelf sea of the east coast of Peninsular Malaysia (ECPM), south of the South China Sea (SCS). The results of a spectral density and harmonic analysis demonstrate that the near-bottom temperature variability and the tidal currents are influenced by diurnal (O₁ and K₁) and semidiurnal (M₂) tidal currents. The spectral density of residual currents (detided data) at 5, 10 and 16 m depth also shows significant peaks at the diurnal tidal frequency (K₁) and small peaks at the semidiurnal tidal frequency (M₂) indicating the existence of internal tides. The result of the horizontal kinetic energy (HKE) shows a strong intermittent energy of internal tides in the ECPM with the strongest energy is found at 16 m depth during a sporadic cooling event in June and July. A high horizontal cross-shore heat flux (16 m) also indicates strong intrusions of cooler water into the ECPM in June and July. During the short duration of cold pulse water observed in June and July, a cross-wavelet analysis also reveals the strong relationship between the near-bottom temperatures and the internal tidal currents at the diurnal tidal frequency. The intrusion of this cooler water is probably related to the monsoon-induced upwelling in June. It is loosely interpreted that the interaction between the strong barotropic tides and the steep slope in the central basin of the SCS under the stratified condition in southwest monsoon has generated these internal tides. The dissipation of internal tides from the slope area probably has driven the cold-upwelled water into the ECPM coastal shelf sea when the upwelling intensity is the highest in June and July.     

Heat content change in the surface isothermal layer of a warm core ring in the sea east of Japan

Heat content change in the surface isothermal layer of a typical warm core ring in the sea east of Japan is described based on approximately 90 CTD profiles obtained by one profiling float. Erosion of the seasonal thermocline and development of a surface isothermal layer from the mid-summer to the early winter of 1999 are clearly seen. While heat content change between two consecutive profiles with a 35-hour time interval is much noisier, its 10-day running mean is consistent with net surface heat flux, indicating that surface heat flux dominates the temporal heat content change in the surface isothermal layer in the warm core ring.     

粤东典型海湾表层沉积物Cd的分布及其潜在生态危害评价*

对粤东海域5个典型海湾64个表层沉积物样进行了重金属Cd含量的测定,分析探讨了其空间分布特征及其主要影响因素,并以南海陆架区Cd含量为背景值计算了粤东5个海湾表层沉积物Cd的潜在生态危害系数。结果显示,柘林湾、汕头湾、汕尾湾、大亚湾和大鹏湾表层沉积物Cd的含量范围分别为0.04—0.58、0.06—6.63、0.06—0.11、0.04—0.20、0.08—0.15 mg·kg?1,其分布表现为：柘林湾养殖区和三百门附近海域以及汕头湾拦沙堤末端海域和好望角附近海域Cd含量高于其他海区,汕尾湾的Cd含量由近岸向外海、西部到东部增加,而大亚湾和大鹏湾外湾含量高。重金属输入和水动力条件是控制 Cd 分布的决定性因素。生态危害评价表明,养殖区、三百门附近海域、拦沙堤末端海域和好望角附近海域Cd污染达到了中等甚至很强的生态危害水平,污染比较严重。来自入海河流携带工业污染物注入、沿岸排污、水产养殖沉降、产业转移人为排放和金属矿床开采释放的 Cd 已造成了近海环境的污染,应当引起相关部门的重视。     

Sedimentary and structural evolution of the Eastern South Korea Plateau (ESKP), East Sea (Japan Sea)

The East Sea (Japan Sea) is a semi-enclosed back-arc basin that is thought to preserve a significant record of tectonic evolution and paleo-climatic changes of Eastern Asia during the Neogene. We use here 2-D regional multi-channel seismic reflection profiles and borehole data from Expedition 346 of the Integrated Ocean Drilling Program (IODP) to provide new constraints on the geological history of the Eastern South Korea Plateau (ESKP). The ESKP represents a structurally-complex basement high in the southwestern East Sea which formed during rifting of the back-arc basin. Our new observations show that the ESKP is composed of numerous horsts and grabens controlled by NE-trending normal faults. The acoustic basement is blanketed by Oligocene to recent sediments that have preferentially accumulated in topographic lows (up to 1.5 km thick) and have been cored during Expedition 346 at Site U1430 close to the southern margin of the ESKP. Seismic profiles in the ESKP reveal three units separated by regional unconformities. These seismic units closely correspond to IODP lithostratigraphic units defined at Site U1430, where biostratigraphic data can be used to constrain the timing of three main evolutionary stages of the ESKP. Stage 1 was related to rifting in the late Oligocene and middle Miocene, terminated by a regional uplift leading to an erosional phase in the middle Miocene. Stage 2 was associated with subsidence in the middle and late Miocene and uplift and accompanying erosion or non-deposition in the latest late Miocene. Stage 3 (Pliocene to present) recorded overall uniform hemipelagic-pelagic subsidence of the ESKP with short-lived tectonically-induced uplifts in the late middle Miocene and latest Miocene-early Pliocene. The three stages of evolution of the ESKP closely correlate to sedimentary changes since the Oligocene and suggest a direct control of regional/local tectonics on sedimentation patterns in the southwestern East Sea, with secondary influence of regional climatic and paleo-oceanographic processes.     

台湾以东中尺度涡对黑潮入侵东海路径的影响

利用AVISO数据集的卫星高度计资料,分析了中国台湾以东中尺度涡的时空特征,通过具体的中尺度涡实例探讨了其对台湾以东黑潮路径的影响。研究表明气旋式中尺度涡在春夏季节的数目要少于反气旋式中尺度涡,在秋冬季节气旋式涡旋个数则多于反气旋涡;并且台东以东区域涡旋传播存在多种路径,涡旋的存在对台湾东北部黑潮入侵东海的路径具有重大影响,特别是2004年夏季台湾以东区域存在多个涡旋,相应的吕宋海峡黑潮主轴向东偏移明显,台湾东北黑潮入侵东海的路径发生了显著变化。     

2010年智利和2011年日本海啸在华南沿岸的实测海啸波形和特征

文章根据三亚湾和台山广海湾实测水位数据,分析了2010年智利和2011年日本海啸在中国近岸传播的海啸波形。通过与2个深海海啸观测浮标(DART)观测到的海啸波形对照,采用功率谱分析和小波分析技术,研究远场海啸在中国华南沿岸的海啸波特征和传播规律。在2次事件中,海啸波通过巴士海峡进入中国南海后,大约3~4h到达华南沿岸。地形效应是决定海啸波能量的重要因素,特定周期的海啸波得到选择性增强。海啸波在近岸海湾持续时间长达2~3d,海啸波周期越长,持续时间越久。2次海啸事件均未对我国沿海造成灾害性影响,但是通过海啸波形的对比分析,能够更好地了解南海北部地形对海啸波的响应特征,为防范海啸提供借鉴。     

粤东-闽南沿岸海域上升流区软水母亚纲一新种和一新记录的记述

报道了2009年5月在粤东-闽南上升流区发现软水母亚纲（Leptomedusae Haeckel,1866）一新种,大腺触丝水母（Lovenella macrogonaLin,XuetHuang,sp.nov.）和我国海域一新记录,脆弱似杯水母[Phi-alella fragilis（Uchida,1938）].大腺触丝水母,新种的鉴别特征如下：伞半球形,外伞上有分散刺细胞,4个大的生殖腺,卵圆形,在辐管中部;4条主辐触手,触手球背部有块状黑色素,具有6~8对侧丝;4个大的间辐位缘疣,球形,具排泄乳突,背部有黑色素分布;24个平衡囊,每个平衡囊具1个平衡石.