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1.
应用2007月7月国家908专项北黄海区块水体调查获取的浊度资料,与同步获得的悬浮物质量浓度进行拟合分析,结果表明,中底层水的相关系数在0.94以上,表层相关度较差.根据调查海域浊度的水平大面分布及选取的6个典型断面的垂直分布,初步阐述了夏季北黄海水体浊度的分布特征——近岸高和底层高,山东半岛北部沿岸、成山角海域和老铁山水道以及庄河河口附近海域为高浊度区.夏季北黄海冷水团对水体浊度分布具有控制性影响:调查海域水体垂向层结稳定,北黄海冷水团海域中下层表现为高盐、低温、高密特征,水体浊度小,且浊度锋面的分布与温度较为相近.同时,夏季北黄海冷水团对悬浮物的分布起到了屏障作用——在山东半岛北部沿岸和辽东半岛南部沿岸阻止了近岸悬浮物的经向输送,而在山东半岛东部沿岸则阻止了近岸悬浮物的纬向输送. 相似文献
2.
《Deep Sea Research Part I: Oceanographic Research Papers》1999,46(3):371-414
The recent changes in the thermohaline circulation of the Eastern Mediteranean caused by a transition from a system with a single source of deep water in the Adriatic to one with an additional source in the Aegean are described and assessed in detail. The name Cretan Sea Overflow Water (CSOW) is proposed for the new deep water mass. CSOW is warmer (θ>13.6°C) and more saline (S>38.80) than the previously dominating Eastern Mediterranean Deep Water (EMDW), causing temperatures and salinities to rise towards the bottom. All major water masses of the Eastern Mediterranean, including the Levantine Intermediate Water (LIW), have been strongly affected by the change. The stronger inflow into the bottom layer caused by the discharge of CSOW into the Ionian and Levantine Basins induced compensatory flows further up in the water column, affecting the circulation at intermediate depth. In the northeastern Ionian Sea the saline intermediate layer consisting of Levantine Intermediate Water and Cretan Intermediate Water (CIW) is found to be less pronounced. The layer thickness has been reduced by factor of about two, concurrently with a reduction of the maximum salinity, reducing advection of saline waters into the Adriatic. As a consequence, a salinity decrease is observed in the Adriatic Deep Water. Outside the Aegean the upwelling of mid-depth waters reaches depths shallow enough so that these waters are advected into the Aegean and form a mid-depth salinity-minimum layer. Notable changes have been found in the nutrient distributions. On the basin-scale the nutrient levels in the upper water column have been elevated by the uplifting of nutrient-rich deeper waters. Nutrient-rich water is now found closer to the euphotic zone than previously, which might induce enhanced biological activity. The observed salinity redistribution, i.e. decreasing values in the upper 500–1400 m and increasing values in the bottom layer, suggests that at least part of the transition is due to an internal redistribution of salt. An initiation of the event by a local enhancement of salinity in the Aegean through a strong change in the fresh water flux is conceivable and is supported by observations. 相似文献
3.
Study about water characteristics(temperature and salinity) from the World Ocean Database(WOD) was conducted in the area of southern South China Sea(SSCS), covering the area of 0°–10°N, 100°–117°E. From interannual analysis, upper layer(10 m) and deep water temperature(50 m) increased from 1951 until 2014. Monthly averaged show that May recorded the highest upper layer temperature while January recorded the lowest. It was different for the deep water which recorded the highest value in September and lowest in February. Contour plot for upper layer temperature in the study area shows presence of thermal front of cold water at southern part of Vietnam tip especially during peak northeast season(December–January). The appearances of warm water were obviously seen during generating southwest monsoon(May–June). Thermocline study revealed the deepest isothermal layer depth(ILD) during peak northeast and southwest monsoon. Temperature threshold at shallow area reach more than 0.8°C during the transitional period. Water mass study described T-S profile based on particular region. Water mass during the southwest monsoon is typically well mixed compared to other seasons while strong separation according to location is very clear. During transitional period between northeast monsoon to southwest monsoon, the increasing of water temperature can be seen at Continental Shelf Water(CSW) which tend to be higher than 29°C and vice versa condition during transitional period between southwest monsoon to northeast monsoon. Dispersion of T-S profile can be seen during southwest monsoon inside Tropical Surface Water(TSW) where the salinity and temperature become higher than during northeast monsoon. 相似文献
4.
J. A. Dalziel 《Marine Chemistry》1995,49(4)
The vertical distribution of reactive mercury has been measured at two stations in the eastern North Atlantic and one station in the southeast Atlantic in conjunction with the IOC Open Ocean Baseline Survey. The average concentrations of reactive Hg in vertical profiles ranged from 0.70 to 1.07 pM with the highest values found at the northeast Atlantic stations and the lowest at the southeast station. No significant concentration gradients were found below the surface mixed layer at the two stations in the eastern North Atlantic. At station 7, in the southeast Atlantic, an increase in reactive Hg was noted in the water adjacent to the mixed layer (35–200 m) which was coincident with an oxygen depletion, down to 20% saturation at 200 m. The concentration of reactive Hg in the North Atlantic Deep Water (0.48–1.34 pM), the Antarctic Intermediate Water (0.47 pM), the Antarctic Bottom Water (0.67–1.25 pM), and the Mediterranean Outflow Water (0.83–1.06 pM) were noted. The trends in Hg concentration in the water masses between stations showed the concentration decreasing with distance from the water mass source except for Hg in the Antarctic Bottom Water. The increase noted in this water mass was attributed to mixing with North Atlantic Deep Water and or release from bottom sediments. 相似文献
5.
Water masses in the subsurface and the intermediate layer are actively formed due to strong winter convection in the Japan
Sea. It is probable that some fraction of pollution is carried into the layer below the sea surface together with these water
masses, so it is important to estimate the formation rate and turnover time of water masses to study the fate of pollutants.
The present study estimates the annual formation rate and the turnover time of water masses using a three-dimensional ocean
circulation model and a particle chasing method. The total annual formation rate of water masses below the sea surface amounted
to about 3.53 ± 0.55 Sv in the Japan Sea. Regarding representative intermediate water masses, the annual formation rate of
the Upper portion of the Japan Sea Proper Water (UJSPW) and the Japan Sea Intermediate Water (JSIW) were estimated to be about
0.38 ± 0.11 and 1.43 ± 0.16 Sv, respectively, although there was little evidence of the formation of deeper water masses below
a depth of about 1500 m in a numerical experiment. An estimate of turnover time shows that the UJSPW and the JSIW circulate
in the intermediate layer of the Japan Sea with timescales of about 22.1 and 2.2 years, respectively. 相似文献
6.
苏育嵩 《中国海洋大学学报(自然科学版)》1989,(Z1)
简要介绍了黄海和东海的地理环境概况,着重分析调查海域的环流系统。有如下一些初步看法与结论。 台湾暖流的前缘混合水,可从长江冲淡水底层穿越而影响到苏北沿岸,直到32°N以北的浅水区域。对马暖流西侧的水体是东海混合水,而其东侧为黑潮分支。黄海暖流的流向在不同季节具有规律的摆动。黄海底层冷水团属于季节性水团,其强盛及消衰与温跃层的形成及消亡紧密相关。黄海底层冷水团与中部底层冷水并非每年彼此独立,它们的共同特征甚至比其差异更明显。夏季东海冷水不能借助爬升侵入黄海底层冷水团内部。在济州岛南部区域,中层的逆温、逆盐现象,是由黄海密度环流的扩散效应与东海冷水沿黄海底层冷水团边界的爬升这两个原因而形成的。 相似文献
7.
《Deep Sea Research Part II: Topical Studies in Oceanography》1999,46(1-2):279-303
The mean horizontal flow field of the tropical Atlantic Ocean is described between 20°N and 20°S from observations and literature results for three layers of the upper ocean, Tropical Surface Water, Central Water, and Antarctic Intermediate Water. Compared to the subtropical gyres the tropical circulation shows several zonal current and countercurrent bands of smaller meridional and vertical extent. The wind-driven Ekman layer in the upper tens of meters of the ocean masks at some places the flow structure of the Tropical Surface Water layer as is the case for the Angola Gyre in the eastern tropical South Atlantic. Although there are regions with a strong seasonal cycle of the Tropical Surface Water circulation, such as the North Equatorial Countercurrent, large regions of the tropics do not show a significant seasonal cycle. In the Central Water layer below, the eastward North and South Equatorial undercurrents appear imbedded in the westward-flowing South Equatorial Current. The Antarcic Intermediate Water layer contains several zonal current bands south of 3°N, but only weak flow exists north of 3°N. The sparse available data suggest that the Equatorial Intermediate Current as well as the Southern and Northern Intermediate Countercurrents extend zonally across the entire equatorial basin. Due to the convergence of northern and southern water masses, the western tropical Atlantic north of the equator is an important site for the mixture of water masses, but more work is needed to better understand the role of the various zonal under- and countercurrents in cross-equatorial water mass transfer. 相似文献
8.
本文基于实测温盐数据等资料,利用水团的浓度混合分析等方法,揭示了热带中东太平洋海域10°N断面的水团构成自上而下分别为东部赤道–热带水团、北太平洋中央水团、加利福尼亚流系水团、南太平洋中央水团、太平洋亚北极水团和太平洋深层水团。分析发现,受热带辐合带影响,9°～10°N海域常年持续的正风应力旋度诱发上升流出现,北太平洋中央水团、加利福尼亚流系水团、南太平洋中央水团和太平洋亚北极水团4个通风潜沉水团经向运动至该纬度带时被抽吸至次表层和中层,并散布在不同深度。以往研究仅指出上述4个水团在海表通风形成后将潜沉并向赤道方向运动,本研究进一步阐明了4个水团潜沉后向热带海域运动的动力机制及其在热带中东太平洋10°N断面的散布深度。研究成果揭示了热带中东太平洋水团与北太平洋副热带、亚极地和南太平洋副热带海区中上层水团间的循环过程,对认识北太平洋高–中–低纬度间物质和能量的交换和再分配具有重要科学价值。 相似文献
9.
Kuh Kim Kyung-Ryul Kim Young-Gyu Kim Yang-Ki Cho Dong-Jin Kang Masaki Takematsu Yuri Volkov 《Progress in Oceanography》2004,61(2-4):157
Water masses in the East Sea are newly defined based upon vertical structure and analysis of CTD data collected in 1993–1999 during Circulation Research of the East Asian Marginal Seas (CREAMS). A distinct salinity minimum layer was found at 1500 m for the first time in the East Sea, which divides the East Sea Central Water (ESCW) above the minimum layer and the East Sea Deep Water (ESDW) below the minimum layer. ESCW is characterized by a tight temperature–salinity relationship in the temperature range of 0.6–0.12 °C, occupying 400–1500 m. It is also high in dissolved oxygen, which has been increasing since 1969, unlike the decrease in the ESDW and East Sea Bottom Water (ESBW). In the eastern Japan Basin a new water with high salinity in the temperature range of 1–5 °C was found in the upper layer and named the High Salinity Intermediate Water (HSIW). The origin of the East Sea Intermediate Water (ESIW), whose characteristics were found near the Korea Strait in the southwestern part of the East Sea in 1981 [Kim, K., & Chung, J. Y. (1984) On the salinity-minimum and dissolved oxygen-maximum layer in the East Sea (Sea of Japan), In T. Ichiye (Ed.), Ocean Hydrodynamics of the Japan and East China Seas (pp. 55–65). Amsterdam: Elsevier Science Publishers], is traced by its low salinity and high dissolved oxygen in the western Japan Basin. CTD data collected in winters of 1995–1999 confirmed that the HSIW and ESIW are formed locally in the Eastern and Western Japan Basin. CREAMS CTD data reveal that overall structure and characteristics of water masses in the East Sea are as complicated as those of the open oceans, where minute variations of salinity in deep waters are carefully magnified to the limit of CTD resolution. Since the 1960s water mass characteristics in the East Sea have changed, as bottom water formation has stopped or slowed down and production of the ESCW has increased recently. 相似文献
10.
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
11.
Summertime hydrographic features in the southeastern Hwanghae 总被引：1，自引：0，他引：1
Heung-Jae Lie 《Progress in Oceanography》1986,17(3-4)
CTD casts in the southeastern Hwanghae (Yellow Sea) were made in August 1983 and 1984 to describe the spatial structure of the summertime hydrographic features. Cold coastal water appeared around the southwestern coast of Korea, which was formed by strong tidal stirring. Tidal mixing in the study area seems to have been enhanced by the presence of many small islands. In the deeper region beyond the tidal front, stratification became much stronger and the bottom layer below seasonal thermocline was occupied mostly by the Hwanghae Cold Water characterized by a temperature lower than 10°C and salinity of 32.5–33.0%.The northeastward extension of the Changjiang Diluted Water was shown by a tongue-like plume of relatively warm fresh water, confined to the thin surface layer 10 m thick. There was no evidence for the Hwanghae Warm Current carrying high salinity water into the eastern Hwanghae along the Korean coast. The warm current was found to flow in a narrow band close to the west and north coast of Chejudo (Cheju Island) and then to pass eastward through the Cheju Strait. Thus the eastern part of the cyclonic circulation in the surface layer cannot be considered to be a northward continuation of the Hwanghae Warm Current. The local salinity maximum in the lower layer off Kunsan and the higher salinity on the west side of the central trough than on the east side would imply a northward flow on the west flank of the trough to compensate for the southward intrusion of the Hwanghae Cold Water, from which an anticyclonic circulation could be expected in the lower layer. 相似文献
12.
渤海、黄海热结构分析 总被引：14，自引：4，他引：14
在多年观测资料基础上,以月平均风应力和周平均海表水温(SST)作为外强迫,对黄海、渤海热结构进行了数值模拟.模拟结果显示渤海的热结构特征自10月至翌年3月为水温垂直均一的冬季型;5～8月为分层结构(由上混合层、跃层、潮混合层组成)的夏季型.4月和9月为两型的过渡期,最低水温出现在2月,最高水温表层出现在8月,底层则在9～10月.黄海沿岸浅水区与渤海有相似的热结构,黄海冷水团和黄海暖流对其中央槽深水区的热结构有重要影响.对底层水的影响而言,前者夏季显著而后者冬季显著,从而导致黄海(槽)的底层水与环境相比呈现夏季冷而冬季暖的特征,底层水温基本上与表面水温的年变化反相;深水区的热结构与渤海相比,均一型结构(1～3月)变短,分层型结构(5～11月)变长,底温年变幅(5℃以内)变小,跃层强度增强.模拟结果还表明,黄海暖流的动力仍然是季风环流,而对黄海冷水团的形成和发展有无动力影响提出质疑. 相似文献
13.
数值模拟结果表明: 冬季长江口及其邻近海区温度分布为近岸低, 外海高; 近岸和海底地形变化缓慢区温度呈垂直均匀分布, 海底地形变化显著的陡坡区生成温度锋; 外海深水区的中上层温度低且呈垂直均匀分布, 底层温度高并形成弱的分层。春季, 近岸温度高、外海低; 近岸温度大致呈垂直均匀分布, 外海出现明显分层; 长江口以北温度表层低、底层高; 长江口及其以南表层和底层温度低, 而中层高; 陡坡区至外海生成温度锋, 随着温度锋自陡坡至外海的下移,锋面以上温度逐渐变为垂直均匀分布, 而锋面以下温度却大致呈水平均匀分布。夏季, 海区的温度分布和春季一样, 为近岸高、外海低; 长江口及其以南近岸浅水区温度呈垂直均匀分布; 长江口以北和长江口及其以南的外海温度自表层至底层由高变低且大致呈水平均匀分布, 并在表层至次表层生成强温跃层, 跃层强度随水深增加迅速减弱, 深底层温度几乎呈均匀分布且保持低温特征。秋季, 海区的温度分布与冬季相同, 也为近岸低, 外海高; 在长江口以北, 近岸温度为表层高, 底层低; 外海底层温度低且大致呈水平均匀分布, 而底层以上温度高且大致呈垂直均匀分布; 长江口及其以南, 近岸温度呈垂直均匀分布, 陡坡至外海的表层至底层生成弱的温度锋,随温度锋自陡坡至外海的下移, 锋面以上温度逐渐变为垂直均匀分布, 长江口以南陡坡区的底层温度几乎呈均匀分布。 相似文献
14.
南黄海冷水域西部溶解氧垂直分布最大值现象的成因分析 总被引：1，自引：2，他引：1
重点分析了南黄海冷水域西部溶解氧(DO)垂直分布中的最大值现象,并对DO浓度与主要环境因子的相关性进行了研究.结果表明:DO垂直分布最大值现象是调查海域DO分布的显著特征,且与SCM现象相伴生;DO垂直分布的最大值深度和量值具有较为明显的区域差异;温、盐是DO最大值层以上水体中氧含量的主要控制因素;一定强度的温跃层形成之后,DO最大值层出现在跃层的下界附近,且其氧含量受控于跃层厚度和生物化学作用,并与跃层厚度呈正相关;底层较低的DO含量是底层水及沉积物中有机物分解耗氧的结果.同时,还成功解释了DO最大值处与次表层叶绿素最大值层位置不吻合且量值不相关的原因,并提出了"DO净积累效应"的观点,不仅从时间跨度以及动态的角度上对DO最大值的形成机制进行了分析,而且从理论上探讨了DO最大值层氧含量(或来源)的构成,指出自DO最大值层开始产生至观测之时该层之下、真光层以内水体中的生物化学作用(或Chl-a总产出)才与氧最大值密切相关.总体来看,水体层化和生物化学作用明显影响着夏季南黄海冷水域西部DO的垂直分布. 相似文献
15.
The circulation and hydrography of the north-eastern North Atlantic has been studied with an emphasis on the upper layers and the deep water types which take part in the thermohaline overturning of the Oceanic Conveyor Belt. Over 900 hydrographic stations were used for this study, mainly from the 1987–1991 period. The hydrographic properties of Subpolar Mode Water in the upper layer, which is transported towards the Norwegian Sea, showed large regional variation. The deep water mass was dominated by the cold inflow of deep water from the Norwegian Sea and by a cyclonic recirculation of Lower Deep Water with a high Antarctic Bottom Water content. At intermediate levels the dominating water type was Labrador Sea Water with only minor influence of Mediterranean Sea Water. In the permanent pycnocline traces of Antarctic Intermediate Water were found.Geostrophic transports have been estimated, and these agreed in order of magnitude with the local heat budget, with current measurements, with data from surface drifters, and with the observed water mass modification. A total of 23 Sv of surface water entered the region, of which 20 Sv originated from the North Atlantic Current, while 3 Sv entered via an eastern boundary current. Of this total, 13 Sv of surface water left the area across the Reykjanes Ridge, and 7 Sv entered the Norwegian Sea, while 3 Sv was entrained by the cold overflow across the Iceland-Scotland Ridge. Approximately 1.4 Sv of Norwegian Sea Deep Water was involved in the overflow into the Iceland Basin, which, with about 1.1 Sv of entrained water and 1.1 Sv recirculating Lower Deep Water, formed a deep northern boundary current in the Iceland Basin. At intermediate depths, where Labrador Sea Water formed the dominant water type, about 2 Sv of entrained surface water contributed to a saline water mass which was transported westwards along the south Icelandic slope. 相似文献
16.
Atlantic Water flow through the Barents and Kara Seas 总被引：2，自引：0，他引：2
Ursula Schauer Harald Loeng Bert Rudels Vladimir K. Ozhigin Wolfgang Dieck 《Deep Sea Research Part I: Oceanographic Research Papers》2002,49(12)
The pathway and transformation of water from the Norwegian Sea across the Barents Sea and through the St. Anna Trough are documented from hydrographic and current measurements of the 1990s. The transport through an array of moorings in the north-eastern Barents Sea was between 0.6 Sv in summer and 2.6 Sv in winter towards the Kara Sea and between zero and 0.3 Sv towards the Barents Sea with a record mean net flow of 1.5 Sv. The westward flow originates in the Fram Strait branch of Atlantic Water at the Eurasian continental slope, while the eastward flow constitutes the Barents Sea branch, continuing from the western Barents Sea opening.About 75% of the eastward flow was colder than 0°C. The flow was strongly sheared, with the highest velocities close to the bottom. A deep layer with almost constant temperature of about −0.5°C throughout the year formed about 50% of the flow to the Kara Sea. This water was a mixture between warm saline Atlantic Water and cold, brine-enriched water generated through freezing and convection in polynyas west of Novaya Zemlya, and possibly also at the Central Bank. Its salinity is lower than that of the Atlantic Water at its entrance to the Barents Sea, because the ice formation occurs in a low salinity surface layer. The released brine increases the salinity and density of the surface layer sufficiently for it to convect, but not necessarily above the salinity of the Atlantic Water. The freshwater west of Novaya Zemlya primarily stems from continental runoff and at the Central Bank probably from ice melt. The amount of fresh water compares to about 22% of the terrestrial freshwater supply to the western Barents Sea. The deep layer continues to the Kara Sea without further change and enters the Nansen Basin at or below the core depth of the warm, saline Fram Strait branch. Because it is colder than 0°C it will not be addressed as Atlantic Water in the Arctic Ocean.In earlier decades, the Atlantic Water advected from Fram Strait was colder by almost 2 K as compared to the 1990s, while the dense Barents Sea water was colder by up to 1 K only in a thin layer at the bottom and the salinity varied significantly. However, also with the resulting higher densities, deep Eurasian Basin water properties were met only in the 1970s. The very low salinities of the Great Salinity Anomaly in 1980 were not discovered in the outflow data. We conclude that the thermal variability of inflowing Atlantic water is damped in the Barents Sea, while the salinity variation is strongly modified through the freshwater conditions and ice growth in the convective area off Novaya Zemlya. 相似文献
17.
In order to clarify the formation and circulation of the Japan/East Sea Intermediate Water (JESIW) and the Upper portion of
the Japan Sea Proper Water (UJSPW), numerical experiments have been carried out using a 3-D ocean circulation model. The UJSPW
is formed in the region southeast off Vladivostok between 41°N and 42°N west of 136°E. Taking the coastal orography near Vladivostok
into account, the formation of the UJSPW results from the deep water convection in winter which is generated by the orchestration
of fresh water supplied from the Amur River and saline water from the Tsushima Warm Current under very cold conditions. The
UJSPW formed is advected by the current at depth near the bottom of the convection and penetrates into the layer below the
JESIW. The origin of the JESIW is the low salinity coastal water along the Russian coast originated by the fresh water from
the Amur River. The coastal low salinity water is advected by the current system in the northwestern Japan Sea and penetrates
into the subsurface below the Tsushima Warm Current region forming a subsurface salinity minimum layer.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
18.
Two field observations were conducted around the Lembeh Strait in September 2015 and 2016, respectively.Evidences indicate that seawater around the Lembeh Strait is consisted of North Pacific Tropical Water(NPTW),North Pacific Intermediate Water(NPIW), North Pacific Tropical Intermediate Water(NPTIW) and Antarctic Intermediate Water(AAIW). Around the Lembeh Strait, there exist some north-south differences in terms of water mass properties. NPTIW is only found in the southern Lembeh Strait. Water mass with the salinity of 34.6 is only detected at 200–240 m between NPTW and NPTIW in the southern Lembeh Strait, and results from the process of mixing between the saltier water transported from the South Pacific Ocean and the lighter water from the North Pacific Ocean and Sulawesi Sea. According to the analysis on mixing layer depth, it is indicated that there exists an onshore surface current in the northern Lembeh Strait and the surface current in the Lembeh Strait is southward.These dramatic differences of water masses demonstrate that the less water exchange has been occurred between the north and south of Lembeh Strait. In 2015, the positive wind stress curl covering the northern Lembeh Strait induces the shoaling of thermocline and deepening of NPIW, which show that the north-south difference of airsea system is possible of inducing north-south differences of seawater properties. 相似文献
19.
Long-term variability in the intermediate layer of the eastern Japan Basin has been investigated to understand the variability
of water mass formation in the East Sea. The simultaneous decrease of temperature at shallower depths and oxygen increasing
at deeper depths in the intermediate layer took place in the late 1960’s and the mid-1980’s. Records of winter sea surface
temperatures and air temperatures showed that there were cold winters that persisted for several years during those periods.
Therefore, it was assumed that a large amount of newly-formed water was supplied to the intermediate layer during those cold
winters. Close analysis suggests that the formation of the Upper Portion of Proper Water occurred in the late 1960’s and the
Central Water in the mid-1980’s. 相似文献
20.
Mizuki Tsuchiya 《Progress in Oceanography》1986,16(4)
There are three major permanent thermostads with roughly the same potential densities in the upper layer of the Atlantic Ocean. One is the thermostad of the 13°C Water in the equatorial Atlantic. The original type of the 13°C Water is formed in the thermocline in the eastern sector of the South Atlantic subtropical gyre by vertical mixing of dense, low-salinity water from the winter outcrop farther south and overlying less dense, high-salinity water. There might also be a lateral contribution of relatively high-salinity water from the Indian Ocean. The original 13°C Water thus formed is transported northwestward along the northern edge of the subtropical gyre and fed into the North Brazilian Current, which flows equatorward along the coast of Brazil. In the region of the equator, the Equatorial Undercurrent and the subsurface North and South Equatorial countercurrents branch off from the North Brazilian Current and carry the 13°C Water eastward to the thermostad region. Vertical mixing does not explain the development of the thermostad, but is found to be essential in determining the ultimate characteristics of the 13°C Water. The other two thermostads are those of the 18°C Water in the Sargasso Sea and the Subantarctic Mode Water in the western South Atlantic. Unlike the 13°C Water, both of these mode waters are formed as thermostads in the surface layer by winter convection, but vertical mixing in the subtropical gyres may play a role in determining their characteristics. All the three thermostads appear to be required to balance the system of flows in opposing directions. 相似文献