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1.
本文基于2006—2007年春、夏、秋、冬季CTD观测的盐度资料分析了苏北沿岸水盐度的季节变化特征,并利用冬、夏季盐度场变化估算了苏北沿岸水的淡水来源。结果表明:冬季苏北沿岸水在东北季风的驱动下顺岸南下,在离开苏北浅滩后转向东南进入东海;夏季低盐的苏北沿岸水分多支向北、向东流出沿岸区,后者汇入南黄海夏季冷水团环流中。估算结果表明苏北沿岸水的淡水来源主要是苏北沿岸的入海径流水,约占总量的65%,次之是降水/蒸发量通量和长江冲淡水沿江苏沿岸的北向扩展。 相似文献
2.
南黄海西北部夏季潮锋的观测和分析 总被引：3，自引：1，他引：2
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. 相似文献
3.
闽南-台湾浅滩上升流区浮游介形虫的生态研究 总被引：1，自引：0，他引：1
1987年12月—1988年11月对闽南-台湾浅滩上升流区调查结果表明,该海区的介形虫基本属暖水性种类,其中以终生营浮游生活的种类占优势(74.5％),后圆真浮萤Euconchoeciamaimai和针刺真浮萤Euconchoecia aculeata为优势种。外海种和近岸种一般都分别在台湾浅滩南部和福建沿岸水城形成密集区,并向相反方向扩散。夏季(6月)的垂直分布表明,近岸密集区的介形虫载浮于涌升水的上层,远岸的种类和数量分布与次表层水爬坡涌升现象颇为一致。秩季(11月)的垂直分布则反映出沿岸偏低温、低盐水向外扩展的趋势。宽假浮萤Pseudoconchoecia concentrica和短形小浮萤Microconchoecia curta等的出现,对夏季近岸上升流的存在有一定的佐证作用。 相似文献
4.
夏季南黄海海水化学要素的分布特征及影响因素 总被引：8，自引：0，他引：8
基于2006年7月对南黄海调查所得资料,对南黄海海水化学要素的分布特征及影响因素进行了探讨.结果表明:(1) 调查海域底层122°E～123°E,33°N以南范围内存在明显的DO亏损现象,证实了长江口外低氧区向南黄海的扩展态势.(2) 南黄海西南部上层水体中的营养盐主要来源于长江冲淡水及苏北沿岸流的输运,且营养盐与盐度之间呈较好的负相关,具有一定的保守性,同时发现表层无机氮盈余状况的分布与该海域环流的扩展途径密切相关;南黄海西南部底层东北向的高营养盐水舌是长江冲淡水、台湾暖流前缘水以及底层有机物分解释放营养盐综合作用的结果;南黄海冷水域因有机物分解而积聚了大量营养盐.(3) 根据南黄海冷水域海水化学要素的断面分布,指出自DO最大值层开始产生至观测之时该层之下、真光层以内光合作用产氧在温跃层下界的积累和保存在氧最大值形成过程中具有极其重要的作用. 相似文献
5.
北黄海温盐分布季节变化特征分析 总被引：9，自引：1，他引：8
利用2006～2007年夏冬春秋4个季节北黄海的大面调查资料,分析了4个季节北黄海温度和盐度大面以及典型断面分布特征,得出以下结论:2007年冷水团势力范围强于2006年,北黄海冷水团的形成受地形影响.黄海暖流冬春季较强,冬季最强,夏季最弱,秋季开始形成.鲁北沿岸流冬季最强,春季减弱,夏秋季消失,但夏季鲁北沿岸存在冬季鲁北沿岸流水的残余体,即鲁北沿岸水.辽南沿岸水4个季节都以低盐为特征,除夏季低盐中心位于庄河口外,其它3个季节低盐中心均位于调查区域的东北角.渤海与北黄海之间的水交换4个季节都存在.春季,断面盐跃层形成滞后于温跃层;秋季,断面盐跃层消失滞后于温跃层. 相似文献
6.
关于黄海的潮混合和浅水锋现象,中国和韩国的学者已有一些报道(赵保仁,1987a，b;赵保仁等,1992;Lie,H-J.，1989)。卫星图片和有关水文观测资料表明,夏季,黄海的浅水锋主要分布在苏北浅滩外侧、山东半岛的成山角一石岛近海、渤海海峡、西朝鲜湾和江华湾湾口附近及朝鲜半岛西南部近海。
为了深入了解黄海苏北浅滩外侧浅水锋的分布和水文结构,我们于1990年7月29日至8月1日对该区域进行了一次水文和水化学的专项调査。本文根据这次调查所得的水文资料,对苏北浅滩外侧的海面冷水和浅水锋的分布特征以及锋区的环流结构进行简要论述。
苏北近海的浅水锋常出现在苏北浅滩外侧的陡坡附近(赵保仁,1987a)。本次调查在这一区域设了5个断面,32个大面站和1个连续站。锋区附近的最小站距约4海里(5′经距)左右。调査区域的水深分布和站位如图1所示。这一海区的地形分布特点是海底坡度较大,34°10′N以北海底陡坡在30-40m等深线之间,34°10′N线以南海底陡坡在20-30m等深线之间,陡坡处坡度达4×10-3左右。此外,在122°10''E线附近,还有一向北伸展的沙脊。观测结果表明,苏北浅滩外侧浅水锋现象与地形特征关系密切。 相似文献
7.
南黄海物理-生物地球化学过程的时空异质性及内在关联和机制 总被引：2，自引：0，他引：2
研究多重物理过程控制下陆架边缘海生物地球化学过程的时空异质性及其生态响应，对于深入认识海洋生态系统具有重要的意义。基于相关历史观测资料和卫星遥感海表温度，本文综合分析了南黄海物理-生物地球化学过程的时空变化和空间异质性特征，探讨了该海域内部典型地理单元之间的内在关联和机制。结果显示，冷季沿岸流南向输送和暖季锋面上升流垂向输运的季节性交替是影响石岛外海与海州湾外侧海域生物地球化学和初级生产的重要物理过程。夏季苏北沿岸水的东北向扩展可形成浒苔离岸/跨区域输送的动力驱动。暖季水体层化显著影响着南黄海中部冷水团海域的生物地球化学过程，春至秋季冷水团海域底层水体中的营养盐逐渐累积，形成了营养盐的重要贮库；层化季节黄海冷水团边界锋区上升流系统的存在使得南黄海叶绿素a和初级生产力高值区位置同海表低温涌升流区总体相一致。冷季南黄海西部南下的冷水与中部北向入侵的暖水共同导致了“S”型锋面的形成；暖季黄海冷水团边界锋区的上升流系统是连接层化海域和近岸区的纽带，可实现对冷水团内部营养盐的提取，从而将冷水团内部和边界区的生物地球化学过程形成有机连接，并在成山角-石岛外海、海州湾外侧、苏北浅滩东部形成三个典型的物理-生物地球化学相互作用区。本研究细化和整合了南黄海区域海洋学研究，揭示了该海域物理-生物地球化学过程的空间异质性特征和不同地理单元之间的关联性及机制，获得了对南黄海水文-生物地球化学-生态过程的综合、系统认知。 相似文献
8.
青岛-石岛近海反气旋中尺度涡旋存在证据及数值模拟 总被引：3，自引：1，他引：2
系统整理的历史实测海流和温盐资料显示出青岛-石岛近海水域全年都存在着中尺度反气旋式涡旋运动.利用二维数值模式,首次模拟出该涡旋的存在,并对这一涡旋的形成机制进行了探讨,数值模拟结果和实测吻合良好.数值计算表明:在冬季盛行风的作用下,山东半岛南岸出现减水,迫使北上的黄海暖流中的一部分向西北方向延伸,在到达山东半岛近海后向右转向,形成东北向沿岸流,这样,与绕过山东半岛大约沿40～50m等深线南下的黄海沿岸流作用,在青岛-石岛近海形成一个中尺度反气旋涡旋.夏季由于偏南风的作用,致使山东半岛南部近海浅水区域海水都向东北方向流动,与沿黄海冷水团锋面南下的黄海沿岸流相作用,由于流速切变也形成了上述涡旋. 相似文献
9.
利用“中韩水循环动力学合作研究”和“中国近海海洋环境综合调查”( 1 996年 4月 -1 999年 1月 )期间各季节 1 2 8°E以西的校正后的 CTD现场水文调查资料 ,对黄、东海温、盐跃层在 4个不同时期 (成长、强盛、消衰和无跃期 )的各特征值的分布特性及其季节变化作了探讨和分析。结果表明 :( 1 )黄海底层显著冷水团的存在 ,使黄海以温跃层占绝对主导地位 ;东海的沿岸海区因受长江径流的影响则以盐跃层为主导。 ( 2 )温跃层的强度主要取决于与其相联的上、下层水团的强弱。冷水团的存在是产生强跃层的根本原因。( 3)夏季东海区双温跃层从浙江近海到济州岛以南水域连成片 ,其分布范围恰好与冬季入侵陆架的黑潮水相一致。 ( 4 )长江冲淡水舌状盐跃层强度等值线在各季节的伸展情况反映了长江冲淡水在各季节的扩散情况 ,一年当中 ,其轴向先从南往北转 ,再从北往南转。 ( 5 )苏北浅滩以及台湾海峡北部终年为无跃区 相似文献
10.
针对渤海及附近海区的曲折岸线变化以及水文资料时空分布不均匀性的特点,使用四维客观分析LOESS方法得到逐月气候态盐度场。结果表明:渤海南部沿岸水扩展和运移受季风影响显著。冬季沿岸水向渤海湾和莱州湾堆积,形成沿山东半岛龙口海岸东向爬行的水舌,该水舌在蓬莱水域向东扩展;夏季沿岸水向渤海中部冲溢,特别是在黄河口附近,其核心区厚度可达8 m,可扩展到119°30′E处,同时莱州湾内的沿岸水向湾内西部收缩。冬季渤海海峡呈现显著"北进南出"水交换态势;夏季渤海海峡定常流方式的水交换特征不明显。 相似文献
11.
Tomoharu Senjyu Noriko Asano Masaji Matsuyama Takashi Ishimaru 《Journal of Oceanography》1998,54(1):29-44
Intermediate intrusion of low salinity water (LSW) into Sagami Bay was investigated on the basis of CTD data taken in Sagami
Bay and off the Boso Peninsula in 1993–1994. In October 1993, water of low temperature (<7.0°C), low salinity (<34.20 psu)
and high dissolved oxygen concentration (>3.5 ml I−1) intruded along the isopycnal surface of {ie29-1} at depths of 320–500 m from the Oshima East Channel to the center of the
bay. On the other hand, the LSW was absent in Sagami Bay in the period of September–November 1994, though it was always found
to the south off the Boso Peninsula. Salinity and dissolved oxygen distributions on relevant isopycnal surfaces and water
characteristics of LSW cores revealed that the LSW intruded from the south off the Boso Peninsula to Sagami Bay through the
Oshima East Channel. The LSW cores were distributed on the continental slope along 500–1000 m isobaths and its onshore-offshore
scales were two to three times the internal deformation radius. Initial phosphate concentrations in the LSW revealed its origin
in the northern seas. These facts suggest that the observed LSW is the submerged Oyashio Water and it flows southwestward
along the continental slope as a density current in the rotating fluid. The variation of the LSW near the center of Sagami
Bay is closely related to the Kuroshio flow path. The duration of LSW in Sagami Bay is 0.5 to 1.5 months. 相似文献
12.
The generation and propagation mechanisms of a Kyucho and a bottom intrusion in the Bungo Channel, Japan, have been studied
numerically using the hydrostatic primitive equations by assuming density stratification during summer. The experiments are
designed to generate a Kuroshio small meander in Hyuga-Nada, which acts as a trigger for these disturbances. After the current
speed of the Kuroshio is changed, a small meander is generated. At the head of the small meander, warm Kuroshio water is engulfed,
and encounters the southwest coast of Shikoku. However, convergence of heat flux on the bump off Cape Ashizuri suppresses
the generation of a warm disturbance, if the current speed is large. As the cold eddy associated with the small meander approaches
Cape Ashizuri, the heat flux diverges on the bump. This heat source forces a warm disturbance, which intrudes along the east
coast of the Bungo Channel as a baroclinic Kelvin wave (a Kyucho). After the cold eddy passes off Cape Ashizuri, the Kuroshio
approaches the bump again. Strong convergence of heat flux then occurs on the bump, which forces a cold disturbance. This
disturbance propagates as a topographic Rossby wave along the shelf break at the mouth of the channel. After the topographic
wave reaches the west end of the shelf break, it intrudes along the bottom layer of the channel as a density current (a bottom
intrusion). These results suggest that a Kyucho and a bottom intrusion are successive events associated with the propagation
of the small meander. 相似文献
13.
Han Mei 《海洋学报(英文版)》2003,22(1):69-74
The palaeochannel evolution in the study region is divided into four stages by such methods as 14C dating. Sea water intrusion through palaeochannels has been studied as a focal point. Palaeochannels are the main passageways through which the sea water intrudes at a higher speed, through many means and in a changeable dynamic state. 相似文献
14.
To clarify the time change in water exchanges between Ise Bay and the adjacent ocean, repeated hydrographic observations were
conducted along the longitudinal section in Ise Bay. The results show that the mixing condition at the bay mouth (Irago Strait)
changed fortnightly in summer. During the spring tides, the strait water below the pycnocline was well-mixed and nearly homogeneous.
By contrast, it was weakly stratified during the neap tide. There is a strong negative correlation between the tidal range
and the density difference between the upper and lower layers at the strait. In summer, the intrusion depth of oceanic water
into the bay and consequent hydrographic conditions inside the bay changed frequently according to the tidal strength. During
the spring tides a prominent bottom front was created at the bay mouth, indicating that the strait water, which is a mixture
of oceanic and bay waters, intruded through the middle layer. On the other hand, during the neaps, cold and saline oceanic
water intruded through the bottom layer into the bay. The intrusion depth is significantly correlated with the tidal range.
It is considered that the wellmixed strait water, which has a density equivalent to the middle layer inside the bay, is lighter
than the bottom bay water and thus intrudes through the middle layer during the spring tides, while insufficient mixing makes
the bottom water at the strait heavier than the bay water, leading to the bottom intrusion during the neap tides. 相似文献
15.
M. Bel Hassen A. Hamza Z. Drira A. Zouari F. Akrout S. Messaoudi L. Aleya H. Ayadi 《Estuarine, Coastal and Shelf Science》2009
We investigated the phytoplankton dynamics (determined by CHEMTAX analysis of HPLC pigment data) and its relationships with nutrients and water column structure, during two oceanographic cruises in May–June and September 2006 in the Gulf of Gabes (south-eastern Mediterranean). The May–June cruise coincided with the beginning of the summer stratification, while a strong stratification occurred in September with a more than 30 m deepening of the thermocline, and a reduction of the euphotic depth. This strong stratification resulted in a shift in nitrogen sources from nitrates to ammonium as well as phosphate depletion (0.2 μM) and a decrease in silicate concentrations (<2 μM). With the exception of chlorophyll a, pigment concentrations were higher in September than in May–June samplings. The pico- and nanophytoplankton were the major contributors to phytoplankton total biomass, accounting for 90% and 87% of total chlorophyll a in May–June and September, respectively. Picoplankton persisted throughout the entire survey, occupying different depth layers. Chlorophytes were present at substantial amounts (average 23% of total chlorophyll a) during May–June; however, they declined in September (average 5%). Diatoms were overall poorly represented in this study (2% of total chlorophyll a), due probably to silicate shortage. Apparently, the nutrient availability, but also the water column stability seemed to be among the major factors determining phytoplankton dynamics. Indeed, cyanobacteria were prominent in surface samples during the period of strong stratification, whereas the relative contribution of chlorophytes decreased, probably due to low phosphate availability. 相似文献
16.
Sea surface temperature (SST) has been measured in the south of Japan using a thermometer set up in the ferry boat to investigate the characteristics of the warm water intrudes into the coastal areas from the Kuroshio. Time series analysis was applied to the SST data with satellite images and hydrographic observation data from April 1987 to September 1989. The results indicate that the warm Kuroshio water intruded into the coastal areas on the Enshu-nada and the Kumano-nada Seas intermittently with periods of about 50 and 20 days associated with the fluctuation of the Kuroshio path and the Kuroshio frontal disturbance respectively. The intrusion with a 50-day period was dominant when the Kuroshio took a stationary small meander path (B- and C-types). The warm water spread to the west at 20 cm s–1, and was estimated to have a depth of 150 m at least and supply enough heat to make up the loss due to the evaporation in the coastal area. During the straight path of the Kuroshio, it was detected that the warm water intruded into coastal areas only with a 20-day period. The warm water that intrudes with a period of 20 days spreads to the west at 25 cm s–1 in a small scale. 相似文献
17.
Investigation of saltwater intrusion and salinity stratification in winter of 2007/2008 in the Zhujiang River Estuary in China 总被引：3，自引：1，他引：2
Saltwater intrusion is a serious environmental problem in the Zhujiang River Estuary(ZRE),which threatens the water supply of fifteen million people.The hydrological observations as well as meteorological and tidal forcing in the winter of 2007/2008 were analyzed to examine the saltwater intrusion in the ZRE.The observational results suggest that the maximum vertical difference of salinity can reach 10 in the Humen Channel during neap tide,but is very small in the Hengmen Channel.The vertically averaged salinity from time series stations during spring tide is higher than that during neap tide.A three-dimensional finite difference model was developed based on the environmental fluid dynamic code(EFDC) to study the mechanism of saltwater intrusion and salinity stratification in the ZRE.By analyzing the salt transport and the temporal variation of saltwater intrusion,the authors found that the net salt transport due to the estuarine circulation during neap tide was more than that during spring tide.This caused salt to advance more into the estuary during neap tide.However,saltwater intrusion was stronger during spring tide than that during neap tide because the spring-neap variation in salt transport was small relative to the total length of the saltwater intrusion.The physical mechanism causing this saltwater intrusion was investigated by a series of sensitivity experiments,in order to examine saltwater intrusion in response to river discharge and winds.The freshwater source was a dominant influencing factor to the saltwater intrusion and controlled salinity structure,vertical stratification and length of the saltwater intrusion.The prevailing northeast monsoon during winter could increase the saltwater intrusion in the ZRE.Though the southwest wind was unfavorable to saltwater intrusion during spring tide,it could increase stratification and saltwater intrusion during neap tide. 相似文献
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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. 相似文献
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Winter convection in the Irminger Sea leading to the formation of Labrador Sea Water (LSW) is analyzed using CTD data collected along the 59.5° N transatlantic section in 2004–2014, winter Argo data from 2012–2014, and daily North American regional reanalysis (NARR). The interannual variability of LSW in the Irminger Sea is investigated. The dissolved oxygen saturation rate of 93% is used to indicate maximal local convection depth. It is shown that the deepest convection (up to 1000 m) resulting in the largest LSW volume that formed in the Irminger Sea in 2008 and 2012. These years were characterized by numerous storms with anomalously strong turbulent heat loss from the ocean to the atmosphere and negative air temperature to the east of the southern tip of Greenland in January–March. LSW became warmer by 0.42°C, saltier by more than 0.03 PSU, and more oxygenated by 8 µmol/kg between 2004 and 2014. A strong LSW decay in the Iceland Basin is also noted. 相似文献