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1.
近海潮锋的分布与温度、盐度乃至海洋生产力的分布都存在紧密联系。基于北部湾东北部的实测数据,对比分析2016—2017年北部湾东北部海域的温度、盐度、密度等分布,并利用ROMS(Regional Ocean Model System)正压与斜压模式,计算Simpson-Hunter (S-H)参数,阐述了潮锋出现位置及其与温度、盐度和密度的关系。结果表明:北部湾东北部潮锋发生的主要区域位于雷州半岛附近,潮混合区温盐密混合较为均匀。利用ROMS模式计算所得的最大垂直平均流速来计算S-H参数,认为潮锋出现位置位于S-H参数值为2处,与实测结果较为一致,且认为正压模式比斜压模式更能准确模拟潮混合区。另外,分析观测数据发现,温度、盐度、密度锋终年存在。近岸处密度锋主要受盐度锋控制,而潮混合产生的盐度锋又容易被径流掩盖。风力较大时三种锋都易向水深更深处推进,潮混合区终年垂向混合较好。 相似文献
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Several numerical experiments were carried out on the formation of water masses and their fronts such as observed in the Kii Channel in winter. Such water masses and fronts may caused by density-induced current system. The phenomenon is assumed to take place in the vertical two-dimensional plane not involving the effect of the earth's rotation. The linear momentum equation and the diffusion-advection equations of salinity and temperature are integrated with respect to time under a vertically hydrostatic condition. The result is that two rolls which correspond to the onshore water mass and the offshore water mass are formed with an accompanying front between them. The apparent diffusion coefficient reaches a relatively great amount inside the water masses and drops down to the eddy diffusivity level at the front. The dependence of the synoptic distributions of the temperature and salinity on several parameters is also examined. Finally another experiment is carried out involving the effect of the earth's rotation, which results in a rather different distribution pattern from that of the non-rotating model. 相似文献
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Thermal and haline fronts in the Yellow/East China Seas: Surface and subsurface seasonality comparison 总被引：1，自引：0，他引：1
Seasonal variability of surface and subsurface thermal/haline fronts in the Yellow/East China Seas (YES) has been investigated
using three-dimensional monthly-mean temperature and salinity data from U.S. Navy’s Generalized Digital Environmental Model
(Version 3.0). The density-compensated Cheju-Yangtze Thermal/Haline Front has (northern and southern) double-tongues. The
northern tongue is most evident throughout the depth from December to April. The southern tongue is persistent at the subsurface
with conspicuous haline fronts. The thermal (haline) frontal intensity of the northern tongue is controlled mainly by the
temperature (salinity) variation on the shoreward (seaward) side of the front. The cold water over the Yangtze Bank is influential
in generating the southern tongue and intensifying the Tsushima Thermal Front. The year-round Cheju-Tsushima Thermal Front
is evident throughout the depth and intensifies from July to December. The northern arc of the Yangtze Ring Haline Front is
manifest in spring and is sustained until summer, whereas the southern one is fully developed in summer because of eastward
migration of the Yangtze Diluted Water. The area showing strong frontal intensity in the Chinese Coastal Haline Front shifts
seasonally north and south along the Zhejiang-Fujian coast. The Generation and evolution of YES fronts are closely associated
with YES circulation (inferred from the linkage of the water masses). Moreover, the subsurface temperature/salinity evolution
on the fronts in the Yellow Sea differs from that in the East China Sea owing to local factors such as wintertime vertical
mixing and a summertime strong thermocline above the Yellow Sea Bottom Cold Water. 相似文献
4.
山东半岛东北部海域悬浮体季节分布及控制因素 总被引：1，自引：0，他引：1
基于2018年山东半岛东北部海域冬、夏两季悬浮体浓度、浊度及水温和盐度调查资料,分析了研究区水体悬浮体浓度的季节性变化,探讨了其控制因素。结果表明:夏季浊度在0.2~37.8FTU之间变化,冬季浊度在1.5~100.1FTU之间变化,均表现为底高表低、东高西低的特征。夏季水温分层明显,表现为表层高、底层低的特征,盐度整体无明显变化;冬季温盐垂向上混合均匀,平面上表现为近岸低温低盐水体向远岸高温高盐水体的过渡。悬浮体浓度分布受潮流、波浪、温跃层和温盐锋面等因素影响。夏季,悬浮体垂向上受到温跃层影响,底层悬浮体难以向表层输运;平面上潮混合和波浪差异性作用阻碍了悬浮体的水平输运。冬季,强风浪促使悬浮体垂向混合剧烈,表层悬浮体浓度明显较夏季变高;平面上沿岸流和黄海暖流形成的温、盐锋面阻碍了水团间悬浮体的输运。 相似文献
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Environmental control of short-term variation in the plankton community of inner Tokyo Bay, Japan 总被引：1，自引：0，他引：1
Toru Nakane Kisaburo Nakaka Heather Bouman Trevor Platt 《Estuarine, Coastal and Shelf Science》2008,78(4):796-810
Water temperature, salinity, nutrient concentrations and the composition of the plankton community were recorded at three stations in inner Tokyo Bay over a period of 328 days (from June 8, 1995 to April 30, 1996) with a nominal sampling frequency of once per day. Inspection of the results revealed that the data could be divided into two blocs as an aid to analysis: the period from June to October was characterized by the development of stratification of temperature and salinity (stratification period), and November to March was characterized by uniform temperature and salinity in the water column due to vertical mixing (mixing period). Oxygen-depleted water forms in the bottom layer during the stratification period, but vertical mixing of the water column, due to changing wind and rainfall conditions caused by passing weather fronts, results in the breakdown of the oxygen-depleted water mass. Nutrient loads are high in the surface water due to the freshwater supply, but occasional pulses of primary production cause a depletion of phosphate in the surface water, suggesting that the phosphorus becomes a limiting nutrient for phytoplankton growth in this period. Several short-term peaks of plankton abundance (blooms) occurred as responses to temporal changes in water quality from June to November, with consequent species succession. Significant fluctuations in the densities of the diatom Skeletonema costatum and several species of ciliates corresponded to the daily changes in the physical and chemical characteristics of the coastal environment. During the mixing period, when water temperature and solar radiation decreased, there were no short-term variations in water quality and although nutrient concentrations gradually increased from November to February, primary production remained low. This study shows that the short-term dynamics of the phytoplankton community are closely coupled to fluctuations in environmental forcing, and that the degree of coupling is stronger during periods when solar radiation is greater. The results provide a novel typological understanding of seasonal plankton dynamics in a shallow, eutrophicated marine embayment, and suggest how such systems may be treated in simulation modeling. 相似文献
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象山港盐度分布和水体混合I.盐度分布和环流结构 总被引：4，自引：1，他引：3
利用１９８１—１９９０年的实测水文资料分析了象山港与混合密切相关的盐度分布和环流结构,并对盐度锋面出现成因进行了探讨。研究结果表明,象山港盐度受长江冲淡水活动影响较大,冬、夏口门附近盐度分别为２４—２５左右和３１以上,湾顶附近盐度季节变化不大。冬季湾内盐度空间梯度较小。夏季湾内有两个盐度锋面出现,水体垂向略有层化但并无明显的跃层出现。此外,象山港狭湾内以重力环流为主,狭湾外以水平环流为主。 相似文献
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The temperature and salinity data obtained by the Iwate Fisheries Technology Center for the 25-year period from 1971 to 1995
were analyzed to clarify the seasonal variations in the sea off Sanriku, Japan. The variations of three typical waters found
in this region, the Tsugaru Current water, the Oyashio water, and the Kuroshio water are discussed in terms, of a T-S scatter
diagram referring to the water mass classification proposed by Hanawa and Mitsudera (1986). The mean temperature and salinity
fields averaged for each month show clear seasonal variation. Distributions of the Tsugaru Current water and the Oyashio water
can barely be distinguished in the fields deeper than 200 m since the Tsugaru Current has a shallow structure; however, the
fields at 100 m depth indicate remarkable seasonal variation in the area of the Tsugaru Current. At 100 m depth, the temperature
and salinity fronts between the Tsugaru Current water and the Oyashio water gradually disappear in January through April,
appear again in May, then become clearest in September.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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SHEN Yongming 《中国海洋工程》2000,14(4):447-458
The prediction of water temperature and salinity in coastal areas is one of the essential tasksin water quality control and management.This paper takes a refined forecasting model of water tempera-ture and salinity in coastal areas as a basic target.Based on the Navier-Stokes equation and κ-ε turbu-lence model,taking the characteristics of coastal areas into account,a refined model for water temperatureand salinity in coastal areas has been developed to simulate the seasonal variations of water temperatureand salinity fields in the Hakata Bay,Japan.The model takes into account the effects of a variety ofhydrodynamic and meteorological factors on water temperature and salinity.It predicts daily fluctuationsin water temperature and salinity at different depths throughout the year.The model has been calibratedwell against the data set of historical water temperature and salinity observations in the Hakata Bay,Japan. 相似文献
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南海中尺度涡温盐结构的季节特征及形成机制 总被引：2，自引：0，他引：2
本文利用最新的涡旋数据集和ARMOR3D数据，研究了南海中尺度涡温盐结构的季节特征及形成机制。合成分析的结果表明，在冬季，涡旋引起温度异常的水平分布在50米以浅表现为类似偶极型分布，而在50m以深则趋向于中心对称分布；在夏季，温度异常的水平分布均表现为中心对称的特征。涡旋引起盐度异常的水平分布也具有类似的季节特征，但是偶极型中的不对称性相对较弱。在垂向上，涡旋所致的温度异常表现为单层结构，而盐度异常则为三层结构。进一步的分析表明，涡旋所致温盐异常的垂向分布特征与背景温盐的垂向分层有关；而在50m以浅，温盐异常的水平分布的不对称特征主要由背景温盐场的水平平流所致。 相似文献
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基于海洋锋空间位置、水平分布结构和垂直扩展特征等时空特征参数,结合海洋锋空间结构几何模型,建立了区域海洋锋温盐三维结构快速重构特征模型,对黄海西部沿岸锋和东海黑潮中段锋锋区温度场进行了仿真计算,并与实测数据进行了比较分析,实验结果表明：仿真结果与实测数据符合较好,实验结果验证了特征模型的有效性和可推广性。海洋锋区声速具有明显的水平梯度变化,对声纳的水下探测和反探测产生显著影响,因此,需要建立实时估计获取锋区水下温、盐结构的方法。海洋锋特征模型能够快速有效地重构海洋锋区温度场,为实时获取海洋锋水下结构特征提供了方法。 相似文献
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The annual subduction rate in the South Indian Ocean was calculated by analyzing Simple Ocean Data Assimilation(SODA) outputs in the period of 1950–2008. The subduction rate census for potential density classes showed a peak corresponding to Indian Ocean subtropical mode water(IOSTMW) in the southwestern part of the South Indian Ocean subtropical gyre. The deeper mixed layer depth, the sharper mixed-layer fronts and the associated relatively faster circulation in the present climatology resulted in a larger lateral induction, which primarily dominants the IOSTMW subduction rate, while with only minor contribution from vertical pumping.Without loss of generality, through careful analysis of the water characteristics in the layer of minimum vertical temperature gradient(LMVTG), the authors suggest that the IOSTMW was identified as a thermostad, with a lateral minimum of low potential vorticity(PV, less than 200×10~(–12) m~(–1)·s~(–1)) and a low d T?dz(less than 1.5°C/(100m)). The IOSTMW within the South Indian Ocean subtropical gyre distributed in the region approximately from25° to 50° E and from 30° to 39°S. Additionally, the average characteristics(temperature, salinity, potential density)of the mode water were estimated about(16.38 ± 0.29)°C,(35.46 ± 0.04),(26.02 ± 0.04) σ_θ over the past 60 years. 相似文献
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Thermal fronts and cross-frontal heat flux in the southern Huanghai Sea and the East China Sea 总被引：1，自引：0，他引：1
Synoptic features in/around thermal fronts and cross-frontal heat fluxes in the southern Huanghai./Yellow Sea and East China Sea （HES） were examined using the data collected from four airborne expendable bathythermograph surveys with horizontal approxmately 35 km and vertical 1 m（from the surface to 400 m deep） spacings. Since the fronts are strongly affected by HES current system, the synoptic thermal features in/around them represent the interaction of currents with surrounding water masses. These features can not be obtained from climatological data. The identified thermal features are listed as follows ： （ 1 ） multiple boundaries of cold water, asymmetric thermocline intrusion, locally-split front by homogeneous water of approxmately 18 ℃, and mergence of the front by the Taiwan Warm Current in/around summertime southern Cheju - Changjiang/Yangtze front and Tsushima front; （2） springtime frontal eddy-like feature around Tsushima front; （3） year-round cyclonic meandering and summertime temperature-inversion at the bottom of the surface mixed layer in Cheju - Tsushima front; and （4） multistructure of Kuroshio front. In the Kuroshio front the mean variance of vertical temperature gradient is an order of degree smaller than that in other HES fronts. The southern Cheju- Changjiang front and Cheju -Tsushima front are connected with each other in the summer with comparable cross-frontal temperature gradient. However, cross-frontal heat flux and lateral eddy diffusivity are stronger in the southern Cheju - Changjiang front. The cross-frontal heat exchange is the largest in the mixing zone between the modified Huanghai Sea bottom cold water and the Tsushima Warm Current, which is attributable to enhanced thermocline intrusions. 相似文献
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Physical oceanographic data were collected during September 1975 at stations in the shallow water (max. depth 45 m) embayments of Salonica Bay and Thermaicos Gulf, and comparisons are made with data collected during other seasons. The distribution of temperature and salinity in the water column indicated the following features: fresh surface water predominantly related to river discharge; an intermediate water mass, apparently formed by mixing between the fresh and open sea waters; a thermocline, and deep bottom water open sea characteristics. The summer distribution of density in the surface and bottom waters, and the seasonal variation in the pattern of surface salinity, suggested an anti-clockwise water circulation throughout the embayments. 相似文献
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Temperature and salinity data obtained by the Iwate Fisheries Technology Center were analyzed for the period 1971–1995. It
was found that occurrence frequency distributions of temperature and salinity are very skewed at depths deeper than 200 m
and that temperature sometimes exceeds m + 5σ (m: mean and σ: standard deviation. If such abnormally high temperatures are
real the 3σ criterion cannot be adopted. Oceanic conditions were surveyed in 1972 and 1979, when temperatures exceeding m
+ 5σ were observed. It was found that the abnormally high temperature (and high salinity) water was the pure Kuroshio Water
introduced into the region due to some special conditions such as abnormal approach of large warm-core ring to the Sanriku
Coast or abnormal northward extension of the Kuroshio along the coast. These events are very rare, occurring only twice in
the 25-year period analyzed, but the abnormally high temperature observed is real.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献