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1.
利用COADS资料,计算北太平洋(包括赤道海区)1949—1979年海表面风应力,对其距平场进行矢量场的EOF分解,得到几个主要的距平风应力模态(EOF1—3)。分析了各自的时空分布特征,分析发现,风应力距平场的EOF1和EOF2模态分别对黑潮大弯曲和E1—Nino事件有重要影响,并讨论了其影响过程,为黑潮大弯曲预报的可能性提供了依据。 相似文献
2.
根据海洋Rossby波的西传特性, 使用一阶斜压Rossby波模型对北太平洋海表面高度的年际变异进行了回报和预测研究。回报结果表明, Rossby 波模型能够较好地模拟北太平洋海表面高度的年际变异。尤其是黑潮延伸区的下游, 模拟结果与卫星观测的相关系数达到0.8以上。预测结果表明, Rossby 波模型在两个纬向分布的海域有显著的预报能力, 分别位于高纬度中部和副热带环流西部。前者可提前5—6年, 后者可提前2—4年。此外, 重点开展了Rossby波模型在西北太平洋的预报能力研究。结果表明, Rossby波模型对中国的边缘海有着很好的预测能力, 包括南海北部、台湾以东和东海黑潮海域, 分别在提前32、40和52个月时能取得最佳的预测效果。 相似文献
3.
Kunio Kutsuwada 《Journal of Oceanography》1988,44(2):68-80
Relationships of the sea level differences between Naze and Nishinoomote and between Kushimoto and Uragami with wind stress over the North Pacific are examined for interannual variability. These sea level differences are considered to be indications of Kuroshio transport in Tokara Strait and Kuroshio path south of Enshu-nada, respectively. In the sea level difference between Kushimoto and Uragami, dominant variations are found to have periods of about seven years and 3–4 years. The variation of about 7-year period, which corresponds to that in the Kuroshio path between the large meander and non-large meander, is coherent with the variation of the wind stress curl in a region about 2,400 km east of the Kii Peninsula, where negative stress curl weakens about two years before the sea level difference drops (i.e. the large meander path in the Kuroshio generates). The variation of the 3–4 year period is coherent with that of the wind stress in a large area covering the eastern equatorial Pacific, which suggests that it links with global-scale atmospheric variations. Interannual variation in sea level difference between Naze and Nishinoomote is not coherent with that between Kushimoto and Uragami, which suggests that it is not related to the variation of the Kuroshio path south of Enshu-nada, but is coherent with that of the zonally-integrated Sverdrup transport in the latitudinal zone along 30°N. It is suggested that the interannual variation of the Kuroshio transport in Tokara Strait can be explained by the barotropic response to the wind stress. 相似文献
4.
Temporal variations of the net Kuroshio transport and its relation to atmospheric variations 总被引：1，自引：0，他引：1
Shusaku Sugimoto Kimio Hanawa Kumiko Narikiyo Megumi Fujimori Toshio Suga 《Journal of Oceanography》2010,66(5):611-619
Temporal variations of the net Kuroshio transport are investigated using long-term hydrographic data from repeat section of
the 137°E meridian from the south of Japan (34°N) to New Guinea (1°S) conducted by the Japan Meteorological Agency. In this
study, boundaries of the Kuroshio and the Kuroshio Counter Current (KCC) are defined based on the sea surface dynamic height
distribution. Westward flows associated with the KCC and cold-core eddy north of the Kuroshio are removed from the eastward
flow associated with the Kuroshio in order to estimate the net Kuroshio transport strictly. The net Kuroshio transport reveals
low-frequency variations: significant signals on a decadal (about 10-year) timescale. The variations of net Kuroshio transport
are predominantly caused by changes in the magnitude of oceanic current speed fields associated with a vertical movement of
the main pycnocline depth around the southern boundary of the Kuroshio: deepening of the main pycnocline around the southern
boundary of the Kuroshio forms a sharp northern upward-tilting slope of the isopycnal surfaces at the Kuroshio region, and
eventually the net Kuroshio transport increases together with the Kuroshio eastward transport. By using a wind-driven hindcast
model, it is found that the main pycnocline depth variation results from the first-mode baroclinic Rossby waves attributable
to two types of Aleutian Low (AL) changes: a change in the magnitude of AL and meridional movement of AL. 相似文献
5.
MU Lin CHI Yong-xiang LIU Shou-hua SONG Jun LIN Xiao-pei LI Yan ZHANG Jian-li 《海洋通报(英文版)》2013,(2):26-36
应用ROMS数值模式配置基本实验模拟了2004年到2006年中国东部海域海平面的季节变化。模拟结果与TOPEX／Poseidon（T／P）卫星高度计观测结果基本一致,海平面年较差从中国沿岸到黑潮路径逐渐变小。将数值模式的风应力项去掉,配置对比实验。与基本实验结果对比发现,对比实验海平面仍然具有季节变化,但是闽浙沿岸和苏北沿岸海平面春夏季异常偏低、秋冬季异常偏高现象消失,中国沿岸向太平洋的海平面变化减弱。春季和秋季,渤、黄海和黑潮附近海平面异于东海的现象减弱。对比实验海平面的年较差的数值明显减小,从近岸向黑潮海平面年较差渐变的过程消失。整个渤黄海的海平面年较差近似。对比实验海平面年较差占基本实验海平面年较差比率从近岸向黑潮路径逐渐增大。 相似文献
6.
为了研究黑潮跨过200m等深线对东海入侵的年际变化特征,本文基于ROMS(Regional Ocean Modeling System)海洋模式,对西北太平洋海域进行了高分辨率的数值模拟,模式水平分辨率高达4km,该分辨率可以很好地分辨黑潮以东区域的中尺度涡旋等过程。模式首先进行了6年的气候态模拟,然后进行了1993到2015年的后报模拟。模式很好地再现了东海陆架已知的环流结构,模拟出的对马海峡和台湾海峡的年平均流量和观测结果也比较一致。基于模式结果,利用旋转经验正交函数(REOF)的方法,对黑潮跨过200m等深线流量的年际变化进行分析。REOF的主要模态表明,黑潮跨过200m等深线对东海陆架的入侵主要发生台湾东北,并且入侵主要集中在黑潮次表层水中。主要模态的时间系数表明,黑潮入侵东海陆架的年平均流量存在一个8年的变化周期。相关性分析表明,黑潮入侵东海陆架的年际变化和太平洋年代际振荡PDO(Pacific Decadal Oscillation)指标具有显著的负相关,其相关系数达–0.63。该相关可以通过如下过程解释:PDO会导致东太平洋风应力涡度异常,由Sverdrup关系可知向赤道的体积输运也会相应地产生异常,根据质量守恒,向赤道体积输运的异常必然通过西边界流-黑潮的异常来平衡,从而导致黑潮入侵东海陆架强烈的年际变化。 相似文献
7.
基于垂向混合坐标系统的海洋模式HYCOM建立了全球大洋气候态环流场.在此基础上与前人研究工作进行对比,分析和讨论了全球风生大洋环流场的季节变化情况.从模拟结果看该模式具有较好的模拟能力,可以合理地模拟南极绕极流、赤道流系、黑潮和湾流等世界各主要大洋流系.从断面温度场、流函数分布和断面流量场等分析显示:南极绕极流堪称世界最强流,湾流整体强于黑潮,3者都具有夏季增强、冬季减弱的特点.HYCOM模式在国外的研究方兴未艾,而在国内的应用尚处在起步阶段.本文通过对该模式的介绍和结果分析,向读者推荐使用该模式. 相似文献
8.
Simulation of a storm surge caused by Typhoon 9918 in the Yatsushiro Sea, Kyushu, Japan was hindcasted by the synchronous
coupled wind-wave-surge model composed of a Meso-scale meteorological model (MM5) for the wind and sea surface pressure, a
spectral third-generation wind-wave model (Wavewatch III) for waves, and the coastal ocean model (Princeton Ocean Model).
Inclusion of the whitecap wave breaking stresses (whitecap dissipation stress) in the coastal ocean model made it possible
to reproduce the extreme surge height in the extremely shallow bay. 相似文献
9.
10.
Propagation of Rossby Waves over Ridges Excited by Interannual Wind Forcing in a Western North Pacific Model 总被引：1，自引：4，他引：1
Numerical experiments with a multi-level general circulation model have been performed to investigate basic processes of westward
propagation of Rossby waves excited by interannual wind stress forcing in an idealized western North Pacific model with ocean
ridges. When the wind forcing with an oscillation period of 3 years is imposed around 180°E and 30°N, far from Japan, barotropic
waves excited by the wind can hardly cross the ridges, such as the Izu-Ogasawara Ridge. On the other hand, a large part of
the first-mode baroclinic waves are transmitted across the ridges, having net mass transport. The propagation speed of the
first-mode baroclinic wave is accelerated (decelerated) when an anticyclonic (cyclonic) circulation is formed at the sea surface,
due to a deeper (shallower) upper layer, and to southward (slightly northward) drift of the circulation. Thus, when the anticyclonic
circulation is formed on the northern side of the cyclonic one, they propagate almost together. The second-mode baroclinic
waves converted from the first-mode ones on the ridges arrive south of Japan, although their effects are small. The resulting
volume transport variation of the western boundary current (the Kuroshio) reaches about 60% of the Sverdrup transport variability
estimated from the wind stress. These characteristics are common for the interannual forcing case with a longer oscillation
period. In the intraseasonal and seasonal forcing cases, on the other hand, the transport variation is much smaller than those
in the interannual forcing cases.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
A hindcast simulation of 75 typhoons and winter monsoons which affected the coastal areas of Korean Peninsula is performed by use of a third generation ocean wave prediction model, WAM-cycle 4 model, loosely coupled with a com-bined tide and surge model. Typhoon wind fields are derived from the planetary marine boundary layer model for effective neutral winds embedding the vortical storm wind from the parameterized Rankin vortex type model in the limited areas of the overall modeled region. The hindcasted results illustrate that significant wave heights (SWH) considering the wave-tide-surge coupled process are significantly different from the results via the decoupled case especially in the region of the estuaries of the Changjiang Estuary, The Hangzhou Bay, and the southwestern tip of Korean Peninsula. This extensive model simulation is the first attempt to investigate the strong wave-tide-surge interaction for the shallow depth area along the coasts of the Yellow Sea and the East China Sea Continental 相似文献
12.
A buoy-mounted Acoustic Doppler Current Profiler was deployed on the shelf break off the northeast coast of Taiwan to monitor current variations in the upper ocean. The acquired data show that the flow in the upper water column was initially southwest and then abruptly turned northwest. This abrupt change occurred in mid-October, starting from the surface layer and then gradually extending to the deeper layer. In contrast with this flow, the flow in the lower water column was southwest over the entire record, but its amplitude was reduced after the middle of October. The abrupt change of current from southwest to northwest is related to the intrusion of Kuroshio. Examination of two CTD casts showed the salinity of the upper ocean to have increased after the directional shift in mid-October, further indicating the Kuroshio intrusion. The sea level data at Keelung provided other evidence for the intrusion of Kuroshio. The sea level descended as the intrusion occurred and kept the low value until the end of the record. The northwest flow, which carried the water away from the northern coast of Taiwan, is responsible for this descent. Although the intrusion of Kuroshio was mainly confined to the upper ocean, it did have influence on the whole water column. Examination of the wind record at Pengchiayu showed that the time of Kuroshio intrusion was not coincident with the intensification of the northeasterly monsoon. The local wind and the current at 20 m were incoherent. Both the variation of Kuroshio current and the fluctuation of Kuroshio path may be responsible for the variation of the local current. Since the intrusion of Kuroshio has a weak relationship with local wind variation, it appears to be induced by non-local factors. 相似文献
13.
Interannual variability of the Kuroshio intrusion in the South China Sea 总被引：13，自引：1，他引：13
Michael J. Caruso Glen G. Gawarkiewicz Robert C. Beardsley 《Journal of Oceanography》2006,62(4):559-575
The interannual variability of intrusions of the Kuroshio into the South China Sea (SCS) is investigated using satellite remote
sensing data supported by in-situ measurements. The mesoscale circulation of the SCS is predominantly wind-forced by the northeast
winter and southwest summer monsoons. Although the region has been studied extensively, considerable uncertainty remains about
the annual and interannual mesoscale nature of the circulation. The frequency and characteristics of Kuroshio intrusions and
their effect on circulation patterns in the northeast SCS are also not well understood. Satellite observations of Sea Surface
Temperature (SST) from the Tropical Rainfall Measuring Mission (TRMM) and the Advanced Very High Resolution Radiometer (AVHRR)
and Sea Surface Height Anomalies (SSHA) from TOPEX/ Poseidon for the period 1997–2005 are used here to analyze the annual
and interannual variability in Kuroshio intrusions and their effects on the region. Analysis of SST and SSHA shows the formation
and characteristics of intrusions vary considerably each year. Typically, the intrusion occurs in the central region of Luzon
Strait and results in an anticyclonic circulation in the northeastern SCS. However, in some years, the intrusion is located
in the northern portion of Luzon Strait and a cyclonic intrusion results. Wind stress and wind stress curl derived from the
National Aeronautics and Space Administration (NASA) QuikSCAT satellite scatterometer are used to evaluate the relationship
between wind stress or wind stress curl and the presence of winter Kuroshio intrusions into the SCS. 相似文献
14.
台湾以东表面黑潮流量与涡旋场相互作用研究 总被引：1，自引：1，他引：0
本文基于法国空间局AVISO中心提供的1993年~2015年的卫星遥感海面高度和海表流场逐日资料，分析了台湾以东表面黑潮流量及其邻近海域的涡旋场（海面高度异常），得到了台湾以东表面黑潮流量和涡旋场的四个主要周期，并研究了不同对应周期的黑潮表面流量及其邻近涡旋场之间的相互作用关系。论文主要结论如下：（1）基于小波分析法，分析了台湾以东表面黑潮流量及其邻近的涡旋场，发现两者都具有明显的季节、年和年际变化周期。对于表面黑潮流量，除了具有182天（0.5年）和365天（1年）的显著周期外，还存在860天（2.35年）和2472天（6.8年）左右的较为明显的周期。涡旋场也相应地存在200天（0.55年）、374天（1年）、889天（2.43年）和2374天（6.5年）四个较明显的周期，但在不同的纬度存在一定差异；（2）基于相关分析和因果分析法，分析了以上四个周期内表面黑潮流量及其邻近涡旋场的相关性，揭示了黑潮与涡旋在不同周期区间、不同纬度相互影响关系的差异。 相似文献
15.
A series of numerical experiments were conducted with a high-resolution (eddy-permitting) North Pacific model to simulate the formation and spreading of the salinity minimum associated with the North Pacific Intermediate Water (NPIW). It was found that two factors are required to simulate a realistic configuration of the salinity minimum: a realistic wind stress field and small-scale disturbances. The NCEP reanalyzed wind stress data lead to better results than the Hellerman and Rosenstein wind stress data, due to the closer location of the simulated Oyashio and Kuroshio at the western boundary. Small-scale disturbances formed by relaxing computational diffusivity included in the advection scheme promote the large-scale isopycnal mixing between the Oyashio and Kuroshio waters, simulating a realistic configuration of the salinity minimum. A detailed analysis of the Oyashio water transport was carried out on the final three-year data of the experiment with reduced computational diffusivity. Simulated transport of the Kuroshio Extension in the intermediate layer is generally smaller than the observed value, while those of the Oyashio and the flow at the subarctic front are comparable to the observed levels. In the Oyashio-Kuroshio interfrontal zone the zonally integrated southward transport of the Oyashio water (140-155°E) is borne by the eddy activity, though the time-mean flow reveals the existence of a coastal Oyashio intrusion. In the eastern part (155°E-180°) the zonally integrated transport of the Oyashio water indicates a southward peak at the southern edge of the Kuroshio Extension, which corresponds to the branching of the recirculating flow from the Kuroshio Extension. 相似文献
16.
Using a combination of Quick Scatterometer (QuikSCAT), Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E),
and Lagrangian drifter measurements, we demonstrate that wind data alone are not sufficient to derive ocean surface stress
(momentum flux) over mid-latitude ocean fronts, specifically the Kuroshio Extension. There was no continuous and large-scale
stress measurement over ocean until the launch of the scatterometers. Stress had been derived from winds through a drag coefficient,
and our concept of stress distribution may be largely influenced by our knowledge of wind distribution. QuikSCAT reveals that
the variability of stress could be very different from wind. The spatial coherence between the magnitude of stress and sea
surface temperature (SST), between the divergence of surface stress and the downwind SST gradient, and between the vorticity
of stress and crosswind SST gradient, are the inherent characteristics of stress (turbulence production by buoyancy) that
would exist even under a uniform wind field. The coherence between stress vorticity and SST gradient is masked by the rotation
of ocean currents over the Kuroshio meanders. Surface stress rotates in the opposite direction to surface currents because
stress is the vector difference between wind and current. The results are in agreement with a previous study of the Agulhas
Extension and confirm the unique stress measuring capability of the scatterometer. 相似文献
17.
Simulation of Formation and Spreading of Salinity Minimum Associated with NPIW Using a High-Resolution Model 总被引：1，自引：2，他引：1
A series of numerical experiments were conducted with a high-resolution (eddy-permitting) North Pacific model to simulate
the formation and spreading of the salinity minimum associated with the North Pacific Intermediate Water (NPIW). It was found
that two factors are required to simulate a realistic configuration of the salinity minimum: a realistic wind stress field
and small-scale disturbances. The NCEP reanalyzed wind stress data lead to better results than the Hellerman and Rosenstein
wind stress data, due to the closer location of the simulated Oyashio and Kuroshio at the western boundary. Small-scale disturbances
formed by relaxing computational diffusivity included in the advection scheme promote the large-scale isopycnal mixing between
the Oyashio and Kuroshio waters, simulating a realistic configuration of the salinity minimum. A detailed analysis of the
Oyashio water transport was carried out on the final three-year data of the experiment with reduced computational diffusivity.
Simulated transport of the Kuroshio Extension in the intermediate layer is generally smaller than the observed value, while
those of the Oyashio and the flow at the subarctic front are comparable to the observed levels. In the Oyashio-Kuroshio interfrontal
zone the zonally integrated southward transport of the Oyashio water (140–155°E) is borne by the eddy activity, though the
time-mean flow reveals the existence of a coastal Oyashio intrusion. In the eastern part (155°E–180°) the zonally integrated
transport of the Oyashio water indicates a southward peak at the southern edge of the Kuroshio Extension, which corresponds
to the branching of the recirculating flow from the Kuroshio Extension.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
Temporal variations of area of the North Pacific Intermediate Water (NPIW), in the repeat hydrographic section along 137°E
meridian conducted by the Japan Meteorological Agency, are investigated using the de-trended variables from 1972 to 2008.
Variations of NPIW area show a clear quasi-decadal (about 10 years) modulation and it is caused by the vertical displacement
of isopycnal surfaces in the lower portion of NPIW around the northern boundary of its distribution (30–32°N): The downward
(upward) movement of isopycnal surfaces in the lower portion of NPIW as a result of the first-mode baroclinic ocean response
stretches (shrinks) the density layer equivalent of NPIW and causes strengthening (weakening) of westward flows associated
with the Kuroshio Counter Current, and then it can induce an increase (decrease) of volume transport of NPIW from the east.
Consequently, the NPIW northern boundary shifts northward (southward) and an increase (decrease) of the NPIW area is induced.
Large-scale atmospheric forcing controlling the vertical displacements of isopycnal surfaces is explored using a wind-driven
hindcast ocean model. The vertical displacements stem from the first-mode baroclinic ocean response to the two types of Aleutian
Low (AL) activities: in particular, the meridional movement of the AL imparts more potential influence on them than the AL
intensity variation does. 相似文献
19.
Long-Term Variability of North Pacific Subtropical Mode Water in Response to Spin-Up of the Subtropical Gyre 总被引：1，自引：0，他引：1
The Meteorological Research Institute's ocean general circulation model (MRI-OGCM) has been used to investigate the temperature
variability of the North Pacific Subtropical Mode Water (NPSTMW) over a time series longer than 5 years via the spin-up of
the subtropical gyre. Besides an interannual variation, the wintertime sea surface temperature in the area where the NPSTMW
is formed, and the temperature of the NPSTMW itself, both change remarkably in a >5-year time scale. An analysis of heat budgets
showed that the long-term changes in NPSTMW temperature are due mainly to a leading advection of heat by the Kuroshio Extension
and compensating surface heat flux. As a result of a dynamical adjustment to the wind stress fields, the transports of the
Kuroshio and the Kuroshio Extension increased in the mid 1970s with a lag of 3 years after the wind stress curl in the central
North Pacific. The increased heat advection by the Kuroshio Extension induces a warming in the mixed layer in the NPSTMW formation
area, followed by a warming of the NPSTMW itself. Both these warming actions increase the heat release to the atmosphere.
These results imply that the surface heat flux over the Kuroshio Extension area varies in response to the change in the ocean
circulation through the spin-up of the subtropical gyre.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
Naoki Hirose 《Journal of Oceanography》2011,67(3):323-336
Significant impacts of the subgridscale parameterizations have been emphasized in modeling the ocean circulations, but various
different parameter values are applied to similar numerical studies often without any justification. This study objectively
estimates a set of empirical parameters along with their uncertainty for circulation modeling of the East Asian Marginal Seas.
The solutions for 14 major parameters are obtained by using model Green’s functions with constraints of climatological temperature
and salinity data. The largest cost function reduction occurs in the eastern Japan Sea associated with the sharp gradient
of the Polar Front. The calibrated parameters are also validated with realistic transport and path of the Kuroshio in the
final experiment. The inverse estimation shows that freshwater discharges from small rivers can be attributed to the coastal
precipitation over a strip of land 74–81 km wide. The thickness diffusion coefficient may be similar to the isopycnal and
horizontal diffusion coefficients in their magnitude. The accelerated initial condition also contributes to the cost function
reduction resulting in weaker trends of deep temperature. Most importantly, estimated scaling factors suggest a significant
reduction of the reanalyzed wind stress data for more realistic ocean circulations. Possible reasons for the momentum missing
are also discussed. 相似文献