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《应用海洋学学报》2015,(4)
通过对WOA13数据库季节平均数据的分析依次得到锋区内0~1 000 m各层锋轴线的位置,对马海流锋轴线位置由表层的40°N附近随深度增加逐渐南移到39°N附近且位置的季节摆动幅度增大.利用绝对梯度方法对温度锋强度与盐度锋强度的水平分布及垂直变化进行了分析;对比了四季锋强度的差异以及差异比率,得到了不同深度不同季节锋强度强弱分布的规律.对比声速穿过锋线时的差异认为表面声速从南到北逐渐减小,锋轴线南北两侧声速差异主要集中在150 m以内,且随深度增加声速差异减小.此外,还运用BELLHOP模型对锋区内700 m以浅的声道特点以及声传播损失进行了简单分析. 相似文献
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丹麦海峡海洋锋可为局地气候变化、海峡鱼类分布以及海峡中尺度涡等方面研究提供参考,在军事领域也具有较高应用价值。然而目前国内外缺乏对于丹麦海峡锋的系统研究。本文利用WOA13数据,对丹麦海峡锋位置、强度空间分布以及相应的季节变化进行了分析。结果显示,锋轴线位置在34°W以西150 m以浅相对稳定,34°W以东锋轴线随深度和季节均有摆动。锋强度在水平和垂直方向分布不均匀,水平方向上锋轴线最大值与最小值差值一般在3倍以上。垂直方向盐度锋主要集中在100 m以浅,且强度随深度不断减小;温度锋强度最大值在表层以下且在300 m以深随深度增加锋强度减小,但有一些区域如27°W和28°W附近,受到海底地形的影响温度锋强度随着深度的变化有大幅度增加的特点。 相似文献
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利用WOA13(1955-2012年)月平均数据提取东海黑潮主轴温度锋信息,并结合海表面温度、PN断面温度结构的季节变化特征,研究东海黑潮主轴温度在垂直方向和水平方向的季节变化,探讨黑潮主轴温度锋季节变化特征,为开展黑潮相关研究提供基础。结果表明WOA13数据对东海黑潮主轴温度锋信息的提取具有较好的效果;在PN断面上,冬、春季节的流核结构最为明显;在130~170 m深度上,东海黑潮主轴温度锋具有明显的季节变化特征,并且可以明显看到黑潮大弯曲的存在;温度锋在150 m上下的深度对黑潮路径的表征较为合理。 相似文献
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基于东海PN断面多年CTD实测资料,主要从PN断面上的温盐结构和声场结构两个方面进行研究,统计分析PN断面上东海黑潮边界锋的水文要素特征。文章利用Matlab软件对资料中所涉及的温盐数据绘制等值线图,描绘出PN断面上关于测站位置、温盐分布特点,利用Mackenzie公式计算声速分布及其变化,从而构成温、盐、声三种要素的断面分布图。此外还进一步分析了PN断面温盐断面结构,得到黑潮锋的分布与强度特征。并对黑潮锋的季节变化规律进行分析,得出夏秋季节黑潮在PN断面上的海洋锋强度相对于冬春季节要大、冬季最弱等结论。 相似文献
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本格拉上升流区域作为大西洋东边界上升流区域,对于区域乃至全球气候均有重要影响;同时上升流区域处于非洲南部与拉丁美洲相近,战略地位重要。海洋锋作为海洋中尺度现象对海汽相互作用、生物多样性,水下声传播等均有较大影响。因此,对本格拉上升流锋时空分布、锋强度季节变化具有较高的科研、经济和军事价值。通过WOA13季节平均数据对上升流锋区三维空间分布特点,锋强度分布季节变化等方面进行了分析。分析结果表明:本格拉上升流锋锋轴线随深度增加逐渐偏离海岸,锋轴线位置随季节改变摆动幅度不大;本格拉上升流锋强度分布具有明显的南北差异,呈现南强北弱的特点,且在浅层温度锋强度有较大季节差异,锋强度垂直方向上最大值位于30~90 m水层内。 相似文献
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基于1980—2015年的SODA(Simple Ocean Data Assimilation)数据,采用绝对梯度方法提取了海洋锋信息,分析了日本海锋区的空间分布特征、锋轴线位置和锋出现频率,研究了日本海温度锋、盐度锋的分布特征和季节变化规律。结果表明:日本海温度锋总体上呈SW—NE走向,季节变化特征显著;锋轴线没有随季节变化发生明显摆动,但随着深度的增加向日本沿岸移动。盐度锋季节性变化规律显著,但轴线位置相对稳定;在整体空间分布上和季节变化上均与温度锋截然不同;整个盐度锋可分为对马海峡锋和日本海北部锋两部分,其中对马海峡锋位于对马海峡附近,具有和当地温度锋相同的特征,日本海北部锋位于日本海最北部,沿着俄罗斯海岸分布。 相似文献
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近年来的现场观测和理论研究发现, 次中尺度现象广泛存在于上层海洋, 其产生与锋生作用及混合层斜压不稳定存在密切联系。本文利用高分辨率的数值模拟结果并结合动力学及能量诊断分析, 对黑潮延伸体海域次中尺度过程的季节变化进行了探讨。探讨结果表明, 黑潮延伸体海域次中尺度过程具有冬季最强, 春季和秋季次之, 夏季最弱的显著季节变化特征。基于冬、夏季次中尺度能量源的诊断可以看到, 这些季节变化特征主要与上层海洋的斜压不稳定和锋生作用有关。冬季, 黑潮延伸体海域的中尺度能量较弱, 但次中尺度过程在季节尺度上表现最为活跃, 这主要与混合层斜压不稳定的作用有关; 夏季, 黑潮延伸体海域的混合层较浅, 次中尺度过程较弱, 但中尺度涡旋活跃, 中尺度流场变形引起的锋生作用对夏季次中尺度现象的产生具有重要影响。在次中尺度能量的季节变化方面, 冬季次中尺度过程从中尺度过程汲取能量的速率远高于夏季, 这是冬季次中尺度过程比夏季更为活跃的主要原因。本文研究结果有助于加深对黑潮延伸体海域次中尺度过程季节性变化及其动力机制的理解。 相似文献
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Spatial and Temporal Variations of Sound Speed at the PN Section 总被引：3，自引：0，他引：3
Gridded sound speed data were calculated using Del Grosso's formulation from the temperature and salinity data at the PN section
in the East China Sea covering 92 cruises between February 1978 and October 2000. The vertical gradients of sound speed are
mainly related to the seasonal variations, and the strong horizontal gradients are mainly related to the Kuroshio and the
upwelling. The standard deviations show that great variations of sound speed exist in the upper layer and in the slope zone.
Empirical orthogonal function analysis shows that contributions of surface heating and the Kuroshio to sound speed variance
are almost equivalent.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Characteristics of variations of water properties and density structure around the Kuroshio in the East China Sea 总被引：5，自引：0，他引：5
Quarterly data of CTD at the PN line in the East China Sea during 1988–94 were analyzed to examine the variations of water
properties and density structure in relation to the Kuroshio. The Kuroshio flows over the continental slope at the PN line.
Water properties in the surface layer less than 100 db change greatly and show a clear seasonal cycle, while those in the
subsurface layer are much less variable. The small isobaric variations in the subsurface layer are almost due to the vertical
movement of isopycnals, on which the water properties vary little. The subsurface variations of salinity, temperature and
isopycnal depth are classified into four groups occurring in the four regions, divided vertically by the middle of the main
pycnocline and horizontally by the offshore edge of the Kuroshio, named Groups 1 (upper Kuroshio), 2 (upper offshore region),
3 (lower Kuroshio), and 4 (lower offshore region). The difference in averaged isopycnal depth between Groups 1 and 2 (3 and
4) is highly correlated with the vertical shear of the Kuroshio velocity in the upper (lower) pycnocline. The isopycnal depth
of Groups 1 and 3 has little annual cycle (with large intraseasonal variations in Group 3), while that of Groups 2 and 4 shows
a clear seasonal variation with the minimum in fall. As a result, the Kuroshio velocity is smallest in fall almost every year,
although the amplitude of seasonal variation and the season of maximum velocity are different from year to year. Interannual
variations of isopycnal depth are characterized by a large amplitude of Group 2 and an opposite phase between Groups 3 and
4, so that the variations of difference in isopycnal depth between Groups 1 and 2 and Groups 3 and 4, i.e., the upper and
lower shear of the Kuroshio velocity, are comparably significant. 相似文献
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The path of the Kuroshio Extension describes two stationary meanders with crests at approximately 144°E and 150°E. The short-term
meridional fluctuations of the warm water spreading northward from the first crest at the surface and its vertical structure
were analyzed by using 5-day-mean surface temperature maps published by JAFIC, montly 100-m-depth temperature maps edited
by the JMA, and CTD data obtained by the R.Vs.Kofu-Maru, Hakuho-Maru andTansei-Maru cruises from 1990 to 1994. A Northern Boundary of the Spreak Kuroshio Water (NBSKW) and a Southern Boundary of the Spread
Kuroshio Water (SBSKW) at the surface were defined as the northern and southern boundary of the pronounced meriodional temperature
gradients, respectively. The vertical structure of the Spread Kuroshio Water was analyzed in terms of its T-S properties.
The location of the NBSKW at the surface corresponds well with the northern boundary of the subsurface high salinity water
that represents the Spread Kuroshio Water. The short-term meridional fluctuations of the northern and southern boundary of
the Spread Kuroshio Water at the surface were studied through the spectral analysis of the maximum latitude of the two lines
defined. We obtained the following results: (1) the meridional fluctuations of the NBSKW and SBSKW at the first creast have
major periods between 16 and 38 days; (2) the 50 day running mean of the SBSKW at the first crest, for the purpòse of this
study, can be generally used as indicative of the location of the Kuroshio axis; and (3) the northward extent of the Spread
Kuroshio Water and the velocity of the meridional shift suggest seasonal variability that could be related with their vertical
structure. 相似文献
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The interannual variability of the temperature structure of the Kuroshio Extension is studied by establishing time series for the period 1950 to 1970 and then comparing it with the time series of sea level differences across the North Equatorial Current obtained by Wyrtki (1975). First, the present analysis shows a significant correlation between the interannual fluctuation of the Kuroshio Extension and the eddy activity south of the Kuroshio axis, suggesting the importance of the eddy-driven mechanism. Secondly, spectral analysis shows close connections between the Kuroshio Extension and the North Equatorial Current with a reasonable time lag of about 1.5 years. This time lag of the mid-latitude variability is also supported by other independent data. In particular, the present preliminary study strongly suggests that the bimodal behavior of the Kuroshio path south of Japan and the intensity of the Kuroshio Countercurrent are closely connected with the Southern Oscillation/El Niño. 相似文献
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Naoto Iwasaka Toshio Suga Kensuke Takeuchi Keisuke Mizuno Yasushi Takatsuki Kentaro Ando Taiyo Kobayashi Eitarou Oka Yasuko Ichikawa Motoki Miyazaki Hiroshi Matsuura Kenji Izawa Chan-Su Yang Nobuyuki Shikama Momoko Aoshima 《Journal of Oceanography》2003,59(1):119-127
We deployed two profiling floats in the region south of the Kuroshio Extension in March 2000. Temperature and salinity profiles
from a depth of 1500 × 104 Pa to the surface are reported every two and four weeks, respectively. The floats performed very well for first four months
after deployment. Later they failed in surfacing for a few months when the sea surface temperature in the region was high.
The salinity sensors seemed to suffer from some damage during their failure-in-surfacing period. Despite this trouble, the
results clearly demonstrate that the profiling float is a very useful and cost-effective tool for physical oceanographic observation
in the open sea.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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吕宋海峡西部深海盆内孤立波潜标观测研究 总被引：2，自引：0，他引：2
Using a net surface heat flux （Qnet） product obtained from the objectively analyzed air-sea fluxes （OAFlux） project and the international satellite cloud climatology project （ISCCP）, and temperature from the simple ocean data assimilation （SODA）, the seasonal variations of the air-sea heat fluxes in the northwestern Pa cific marginal seas （NPMS） and their roles in sea surface temperature （SST） seasonality are studied. The seasonal variations of Qnet, which is generally determined by the seasonal cycle of latent heat flux （LH）, are in response to the advection-induced changes of SST over the Kuroshio and its extension. Two dynamic regimes are identified in the NPMS： one is the area along the Kuroshio and its extension, and the other is the area outside the Kuroshio. The oceanic thermal advection dominates the variations of SST and hence the sea-air humidity plays a primary role and explains the maximum heat losing along the Kuroshio. The heat transported by the Kuroshio leads to a longer period of heat losing over the Kuroshio and its Extension. Positive anomaly of heat content corresponds with the maximum heat loss along the Kuroshio. The oceanic advection controls the variations of heat content and hence the surface heat flux. This study will help us understand the mechanism controlling variations of the coupled ocean-atmosphere system in the NPMS. In the Kuroshio region, the ocean current controls the ocean temperature along the main stream of the Ku roshio, and at the same time, forces the air-sea fluxes. 相似文献
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Four surveys of airborne expendable bathythermograph with horizontal spacing of about 35 km and vertical spacing of 1 m extending
from the surface down to 400 m deep are used to analyze thermal finestructures and their seasonality in frontal zones of the
southern Yellow Sea and the East China Sea. Finestructure characteristics are different not only among fronts but also along
the same front, implying different mixing mechanisms. Summer thermocline intrusions with thickness from few to 40 meters,
generated by the vertically-sheared advection, are identified along the southern tongue of the Cheju-Yangtze Front (especially
south of Cheju Island). The finestructures south of the Yangtze Bank (i.e. the western tip of the southern tongue) produced
by strong along-frontal currents are not as rich as elsewhere in the southern tongue. The Cheju-Tsushima Front presents mixed
finestructures due to confluent currents from various origins. The irregular-staircase finestructures in the Kuroshio region
(below the seasonal thermocline), driven by double-diffusive mixing, show seasonal invariance and vertical/horizontal coherence.
The strength of mixing related to finestructure is weaker in the Kuroshio region than in the Cheju-Tsushima Front or south
of Cheju Island. The profiles in the Tsushima Warm Current branching area show large (∼50 m thick), irregular-staircase structures
at the upper 230 m depth, which coincides roughly with the lower boundary of the maximum salinity layer. The finestructure
at depths deeper 230 m is similar to that in the Kuroshio region. The possible mechanisms for generating the finestructures
are also discussed. 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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The influence of the Kuroshio flow on the horizontal distribution of North Pacific Intermediate Water (NPIW) in the Shikoku
Basin is examined based upon observational data collected by the training vessel “Seisui-maru” of Mie University together
with oceanographic data compiled by the Japan Oceanographic Data Center (JODC). Although it has been stated that the NPIW
with salinity less than 34.2 psu had been confined to the south of the Kuroshio main axis along the PT (KJ) Line on the eastern
side of the Izu Ridge, a similar tendency can be detected on the western side of the Izu Ridge. Namely, the NPIW on the southern
side of the Kuroshio main axis in the Shihoku Basin does not indicate a tendency to go northward across the Kuroshio main
axis without an increase in salinity of more than 34.2 psu. However, the JODC data show that less saline water (<34.2 psu)
was present on the northern side of the Kuroshio main axis south of the Kii Peninsula in May 1992. Satellite observed sea
surface temperature (SST) data suggested that the Kuroshio approaches the Kii Peninsula after forming a small meander off
Kyushu and some intrusions of the NPIW into the northern coastal side of the Kuroshio main axis occurred in this period. It
is concluded that intrusion of the NPIW with salinity less than 34.2 psu to the northern coastal side through the Kuroshio
main axis occurred during the decay period of the small meander path in May 1992. Based on these observational results, the
source of the salinity minimum water on the northern coastal side of the Kuroshio main axis is discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献