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1.
东、黄海海表面温度季节内变化特征的EOF分析 总被引：7，自引：0，他引：7
基于1998—2004年的TRMM/TMI卫星遥感海面温度(SST)数据,在初步分析东、黄海SST的季节分布特征的基础上,采用EOF方法分析了SST的季节内变化特征,进而对SST季节内变化的可能机制进行了探讨。EOF分析获得的前4个模态的累积方差贡献率为57.07%,其结果基本反映了东、黄海SST变化的主要物理过程。其中,EOF的第一模态的方差贡献率占30.17%,其空间模态揭示了以东海北部为中心的、整个海域SST变化趋于一致的特征,这一模态的显著变化周期为6.3周;第二模态的方差贡献率占14.36%,其空间模态呈现东南海域与西北海域SST的反相变化趋势,显著变化周期为8.7周和10.6周;第三模态的方差贡献率占7.02%,其空间SST变率最大的区域位于黄海海域,显著变化周期为6.8,8.7,10.2周等;第四模态的方差贡献率占5.52%,其空间SST变率最大的区域位于东、黄海近海,显著变化周期为6.8周。东、黄海SST季节内变化与此海区大气中的季节内振荡是紧密相关的。 相似文献
2.
Recent investigation suggests that volume transport through the Tsushima/Korea Strait often has double peaks during the summer
to autumn period with decreasing transport in September. The satellite-observed wind changes from weak northwestward (across-strait)
in summer to strong southwestward (along-strait) in early autumn (September) in the strait. Such a strong along-strait wind
is related to tropical cyclones, which frequently pass through the East China Sea in September. The effect of the along-strait
wind component on the transport variation is examined using a three-dimensional numerical model. The simulated volume transport
through the Tsushima/Korea Strait shows realistic seasonal and intra-seasonal variations. According to sensitivity experiments
on local winds, the transport variations in September are mainly generated by strong along-strait (southwestward) wind rather
than weak across-strait wind. The strait transport responds to the along-strait wind (southeastward), which produces a sea
level increase along the Korean coast, resulting in the geostrophic balance across the strait. The transport minimum through
the Tsushima/Korea Strait in September can be determined by the combination of the across-strait geostrophic and along-strait
ageostrophic balances.
The Editor-in-Chief does not recommend the usage of the term “Japan/East Sea” in place of “Sea of Japan”. 相似文献
3.
2008年冬季台湾海峡及其邻近海域QuikSCAT卫星遥感风场的检验及应用分析 总被引：2，自引：0，他引：2
采用布放在台湾海峡及其邻近海域的2个浮标对2008年冬季（2008年12月至2009年2月）QuikSCAT卫星遥感观测的风场资料进行了检验.结果表明,这两者风速的相关系数为0.93,平均偏差为-0.03 m/s,均方根误差为1.10 m/s,平均绝对误差为1.54 m/s;风向平均偏差为-9.53°,均方根误差为22.83°,平均绝对误差为33.84.°这表明QuikSCAT卫星遥感风场资料在台湾海峡及其邻近海域冬季风观测中具有很高的适用性.本文利用2008年冬季QuikSCAT卫星遥感的平均风速场,分析了在＂狭管效应＂影响下台湾海峡及其邻近海域的风速特征.结果显示其平均风速具有3个基本特征：（1）台湾海峡中部存在着明显高于附近其他海域的高风速区,平均风速高出1~4m/s,风速高值区更贴近海峡东岸.（2）台湾海峡南部平均风速大于北部.（3）台湾岛东北角和西南角各有一个风速低值区.结合对2009年2月15~18日一次冷空气大风过程的分析发现,风速越大台湾海峡＂狭管效应＂越明显. 相似文献
4.
5.
In this study, we used the National Centers for Environmental Prediction monthly sea surface temperature (SST) and surface
air temperature (SAT) data during 1982–1994 and the National Center for Atmospheric Research surface wind stress curl data
during 1982–1989 to investigate the Japan Sea SST temporal and spatial variabilities and their relations to atmospheric forcing.
First, we found an asymmetry in the correlation coefficients between SST and wind stress curl, which implies that the SST
variability at the scales of the order of one month is largely due to atmospheric forcing. Second, we performed three analyses
on the data fields: annual mean, composite analysis to obtain the monthly anomaly relative to the annual mean, and empirical
orthogonal function (EOF) analysis on the residue data relative to the summation of the annual mean and the monthly anomaly.
The first EOF mode of SST accounts for 59.9% of the variance and represents the Subpolar Front. The temporal variation of
the first EOF mode implies that the deep Japan Sea could be cooler in cold seasons (November–April) of 1984–1987. Third, we
computed cross-correlation coefficients among various principal components and found that the atmospheric warming/cooling
is the key factor causing intra-seasonal and interannual SST variabilities. 相似文献
6.
WindSat近海岸风场与美国沿岸浮标对比分析 总被引：1，自引：1，他引：0
利用美国近海岸2004-2014年的固定浮标数据,本文对比分析了WindSat的近海岸风速产品。匹配时空窗口分别为30分钟和25公里。对比分析结果表明：WindSat反演的美国近海岸风速产品的均方根误差优于1.44 m/s,并且东海岸风速反演结果优于西海岸。WindSat下降轨道的风速反演结果优于上升轨道的结果。通过浮标相互间的对比分析发现,WindSat近海岸的风速反演结果与近岸海水深度、经度及距岸距离等因素并无明显的相关性。此外,利用2007-2008年的固定浮标数据,本文还对比分析了WindSat和QuikSCAT的近海岸风速反演结果,结果表明：相对于浮标数据,WindSat的风速反演值偏低,而QuikSCAT的风速反演值偏高;总体上来看,WindSat的近岸风速反演结果略优于QuikSCAT的近海岸风速反演结果。以上风速反演的精度均达到了传感器设定的指标,其为进一步的科学研究提供了良好的数据支撑。 相似文献
7.
The annual variabilities of the sea surface height in the Pacific Ocean were investigated by analyzing the TOPEX/POSEIDON
satellite data and by solving a reduced gravity model. We discuss how adequately the simple model can capture the variabilities
of the sea surface height, and what the cause of the variabilities is. Three large amplitude peaks in the satellite data are
found along the 12°N longitude line. Two elongated zones with a large amplitude are also found: one extends east-west along
6°N and the other extends northwestward from South America around 25°S. These features are adequately reproduced in the numerical
simulation of the reduced gravity model. The propagation of the Rossby wave is analyzed by the use of the extended Eliassen-Palm
flux to investigate the mechanism of these annual variabilities. The two east peaks around 12°N can be explained in terms
of the interference between the local Ekman pumping and the free wave emitted near the western coast of North America, and
the most western peak is affected by the Rossby wave formed by the local wind stress. The elongated zonal area around 6°N
is mainly due to the local Ekman pumping. Another area around 25°S results from the convergence of the free Rossby wave emitted
from the eastern boundary and the area with the strong wind stress curl off South America. A discrepancy between the satellite
data and the model results suggests that the eastern equatorial Pacific Ocean is relatively calm in the model but not in the
satellite data.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
An ocean model was used to examine whether the scatterometer winds can improve the model performance both dynamically and thermodynamically. Comparisons were done using QuikSCAT and NCEP2 winds for both the mean and variability from 2000 to 2004. The comparisons showed that the model forced by QuikSCAT winds gives more realistic mean SST, 20 °C isotherm depth (Z20), and latent heat flux than NCEP2 winds do. Sensitivity experiments indicated that QuikSCAT mean wind stress is important for the improved mean SST, Z20, and latent heat release to the atmosphere in the eastern Pacific. QuikSCAT wind speed, through its effect on the turbulent heat fluxes, is most important for the mean SST in the western Pacific. Finally, there were comparable correlations with observations of both SST and Z20 on the intra-seasonal time scale between the model forced with QuikSCAT winds and the model forced with NCEP2 winds. 相似文献
9.
基于第三版本HOAPs (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data)海表面温度、潜热通量、感热通量、海表面空气比湿以及海表面风场5个参量的18 a(1988～2005年)逐月平均资料,利用经验正交函数和奇异值分解方法分析了异常潜热和感热通量场在西北太平洋的时空分布特征及造成这种分布的主要影响因素.EOF的分析结果表明,异常潜热通量场主要体现为第一第二两个模态的变化,第一模态显示整个海域呈同相变化且在时间上呈准年周期变化,第二模态则描述了分别位于10°N,25°N和40°N的3个极值中心并伴随多年振荡,由因子载荷分布可知热带太平洋是第二模态的行为中心,因此该模态可能与ENSO事件相关.异常感热通量场则主要表现为第一模态的变化,在时间上呈准年周期变化并伴随有多年时间尺度的振荡.奇异值分解方法的分析结果表明异常海表面风场是异常潜热和感热通量场时空变化的重要影响因素. 相似文献
10.
东、黄海SST与850hPa气温季节变化关系的SVD分析 总被引：2，自引：0，他引：2
利用1998~2004年的热带降雨测量卫星的卫星遥感海表面温度(SST)数据以及美国NO-AA/NCEP再分析产品的850 hPa气温数据,采用EOF分析方法,分析了850 hPa气温的季节内变化特征,运用奇异值分解(SVD)分析方法对东、黄海SST与850 hPa气温季节内变化的相关关系进行了分析。对850 hPa气温季节内变化的EOF分析结果表明,EOF分析获得的前4个模态的累积方差贡献率为86.51%,其中EOF的第一模态的方差贡献率占44.49%,其空间模态呈现出明显的东南海域为正值、西北海域为负值的反相分布特征,这一模态的显著变化周期为6.6周(约46 d)和2.8周(约19 d)。SVD分析结果表明,第一对模态的协方差解释率为83.6%,基本上能体现出SST温度场与850 hPa气温场季节变化的特征,其空间分布型表明,东海北部以及黄海近岸等海区SST季节变化与30°N以南的东海海区850 hPa气温的季节振荡存在显著的正相关关系,SVD第一对模态空间分布型时间系数之间的相关系数达到0.29。 相似文献
11.
A three-dimensional numerical model is used to simulate sea level and velocity variations in the South China Sea for 1992–1995. The model is driven by daily wind and daily sea surface temperature fields derived from the NCEP/NCAR 40-year reanalysis project. The four-year model outputs are analyzed using time-domain Empirical Orthogonal Functions (EOF). Spatial and temporal variations of the first two modes from the simulation compare favorably with those derived from satellite altimetry. Mode 1, which is associated with a southern gyre, shows symmetric seasonal reversal. Mode 2, which contributes to a northern gyre, is responsible for the asymmetric seasonal and interannual variations. In winter, the southern and northern cyclonic gyres combine into a strong basin-wide cyclonic gyre. In summer, a cyclonic northern gyre and an anticyclonic southern gyre form a dipole with a jet leaving the coast of Vietnam. Interannual variations are particularly noticeable during El Niño. The winter gyre is generally weakened and confined to the southern basin, and the summer dipole structure does not form. Vertical motions weaken accordingly with the basin-wide circulation. Variations of the wind stress curl in the first two EOF modes coincide with those of the model-derived sea level and horizontal velocities. The mode 1 wind stress curl, significant in the southern basin, coincides with the reversal of the southern gyre. The mode 2 curl, large in the central basin, is responsible for the asymmetry in the winter and summer gyres. Lack of the mode 2 contribution during El Niño events weakens the circulation. The agreement indicates that changes in the wind stress curl contribute to the seasonal and interannual variations in the South China Sea. 相似文献
12.
Sang-Ho Lee Moon-Jin Kim Chang-Soo Kim Byoung-Ju Choi Hong-Bae Moon 《Ocean Science Journal》2017,52(3):307-327
To examine the surface circulation and vertical structure of currents in the region of the Keum River (KR) plume, we analyzed the subinertial surface currents obtained by high frequency radar and the vertical profiles of currents measured at a station (M1) located 10 km distance from the estuary mouth for one month in late spring 2008. Monthly-mean surface circulation is composed of the westward flow from the estuary mouth and the northward flow in the offshore. These surface mean currents are a gradient (geostrophic) current around the monthly-mean plume bulge. Dominant variabilities of the surface currents, winds, and KR-outflow are decomposed by the Empirical Orthogonal Functions (EOF). The first current EOF mode, explaining 39% of total variation, is primarily related to the first wind EOF mode varying along the coast and the second current mode, explaining 33% of total variation, is mainly related to the first KR-outflow EOF mode varying along the mean KR-outflow direction. Meanwhile, vertical profile of the monthly-mean current at M1 shows a two-layer structure of the current flowing offshore (onshore) in the upper (lower) layer because the water column is divided by a pycnocline at 7-9 m depths below the plume water. This two layer structure is a background persisting current structure, at least in spring, maintained by the geostrophic balance induced by the sea level slope and density gradient along the line normal to the westward mean surface current direction due to monthly-mean plume bulge off the KR estuary. EOF analysis of vertical current profiles reveals that the first mode, explaining 43% of total variation, represents the two-layer structure of the current variability. The upper-layer current varies along a line normal to the mainland coastline and the low-layer one varies approximately along a line parallel to the coastline, with direction difference of about 115° between the upper-and low-layer. From the correlation analysis it is found that 60% of the first mode variation is influenced by the first mode of KR-outflow and 36% by the first mode of wind. Any forcing modes of KR-outflow and wind influencing the other current vertical modes could not be found in the present study. 相似文献
13.
《Oceanologica Acta》1999,22(1):1-17
Sea surface elevation in the South China Sea is examined in the Topex/Poseidon altimeter data from 1992 to 1995. Sea level anomalies are smoothed along satellite tracks and in time with tidal errors reduced by harmonic analysis. The smoothed data are sampled every ten days with an along-track separation of about 40 km. The data reveal significant annual variations in sea level. In winter, low sea level is over the entire deep basin with two local lows centred off Luzon and the Sunda Shelf. In summer, sea level is high off Luzon and off the Sunda Shelf, and a low off Vietnam separates the two highs. The boundary between the Vietnam low and Sunda high coincides with the location of a jet leaving the coast of Vietnam described in earlier studies. Principal component analysis shows that the sea level variation consists mainly of two modes, corresponding well to the first two modes of the wind stress curl. Mode 1 represents the oscillation in the southern basin and shows little inter-annual variation. The mode 2 oscillation is weak in the southern basin and is strongest off central Vietnam. During the winters of 1992–1993 and 1994–1995 and the following summers, the wind stress curl is weak, and the mode 2 sea level variation in the northern basin is reduced, resulting in weaker winter and summer gyres. Weakening of the Vietnam low in summer implies diminishing of the eastward jet leaving the coast of Vietnam. The results are consistent with model simulations. 相似文献
14.
采用TOPEX/POSEIDON(T/P)卫星高度计 1 993年 1月— 2 0 0 0年 1 2月海面高度数据 ,研究包含了整个南极绕极流流系 (40°— 6 0°S)的海面高度低频变化。首先采用EOF分解方法获取南大洋时空分布的主要模态 ,前 3个EOF模态分别占总方差的 2 4 .8%、1 3 .8%和 1 0 .7%。然后采用EMD方法分别分析了各个EOF模态的时间系数曲线的组成成分 ,对南极绕极流海域的各种时间尺度变化给出了清晰的描述 ,对于不同尺度变化所占的比例得到了定量的结果。研究结果表明 ,EOF的各个模态不仅在形态上存在差异 ,而且具有相互独立的物理背景。EOF的第一模态主要体现了以太阳辐射冬夏差异形成的年周期变化 ,另一个显著的特征就是南极绕极流从 1 993— 2 0 0 0年海面的整体上升趋势。EOF的第二模态体现了陆地地形对南极绕极流的约束作用 ,同时也显示了ENSO过程对南极绕极流 ,特别是对南太平洋的海面高度变化的影响。EOF的第三模态则体现了南极绕极流对南大洋表面风场东西方向不均匀变化的响应。同时 ,本文的研究也证明了EOF与EMD方法联合使用对揭示大范围时空变化有重要的实际意义 相似文献
15.
Using a simple damped slab model,it was possible to show that a local wind induced 88%(15 of 17)of the near-inertial oscillations(NIO)observed in the mixed layer near the east coast of Korea from 1999 to 2004.The model,however,overestimated the energy level in about two-thirds of the simulated cases,because the slab model was forced with winds whose characteristic period was shorter than the damping time scale of the model at 1.5 d.At the observation site,due to typhoons and orographic effects,high-frequency wind forcing is quite common,as is the overestimation of the energy level in the slab model results.In short,a simple slab model with a damping time-scale of about 1.5 d would be enough to show that the local wind was the main energy source of the near-inertial energy in this area,but the model could not be used to accurately estimate the amount of the work done by the wind to the mixed layer. 相似文献
16.
吕宋冷涡的季节变化特征及其与风应力的关系 总被引：1，自引：0，他引：1
利用AVISO提供的1993年1月至2007年5月的多卫星融合海面高度距平（SLA）数据，对研究区域（15°～20°N，113°～121°E）SLA的季节变化特征进行了分析．其结果表明：吕宋冷涡发生在冬、春季，且该冷涡的发生、发展与局地风应力具有较好的相关性；当SLA变化滞后于风应力1个月时，SLA与风应力的负相关系数达-0．78；且当出现西南风时，SLA为正值；而在东北季风期间，S／A为负值．对幽进行主成分分析得到的前2个模态反映了黝的季节变化特性，其中第一模态的贡献率为54．14％，表现为以18．5°N，119．5°E附近为中心的SLA同步涨落，对风应力的响应迟滞1个月，而且此模态与风应力模第一模态的空间分布十分相似；第二模态的贡献率则为14．54％，表现为季风作用下海面高度的Ekman调整． 相似文献
17.
Seasonal and spatial distributions of phytoplankton biomass associated with monsoon and oceanic environments in the South China Sea 总被引：5，自引：3，他引：2
Seasonal variations of phytoplankton/chlorophyll-a （Chl-a） distribution, sea surface wind, sea height anomaly, sea surface temperature and other oceanic environments for long periods are analyzed in the South China Sea （SCS）, especially in the two typical regions off the east coast of Vietnam and off the northwest coast of Luzon, using remote sensing data and other oceanographic data. The results show that seasonal and spatial distributions of phytoplankton biomass in the SCS are primarily influenced by the monsoon winds and oceanic environments. Off the east coast of Vietnam, Chl-a concentration is a peak in August, a jet shape extending into the interior SCS, which is associated with strong southwesterly monsoon winds, the coastal upwetling induced by offshore Ekman transport and the strong offshore current in the western SCS. In December, high Chl-a concentration appears in the upwelling region off the northwest coast of Luzon and spreads southwestward. Strong mixing by the strong northeasterly monsoon winds, the cyclonic circulation, southwestward coastal currents and river discharge have impacts on distribution of phytoplankton, so that the high phytoplankton biomass extends from the coastal areas over the northern SCS to the entire SCS in winter. These research activities could be important for revealing spatial and temporal patterns of phytoplankton and their interactions with physical environments in the SCS. 相似文献
18.
The effects of intra-seasonal wind forcing on the mean field of the tropical Pacific Ocean has been studied using an ocean general circulation model (GCM). Idealized intra-seasonal zonal wind forcing with zero mean, which propagates eastward, induces net eastward jets at the equator that shift the warm water pool to the east. The mean temperature of the upper 200 m of the ocean increases off the equator and decreases at the equator. The change is independent of the propagation speed of the intra-seasonal wind forcing. The magnitude of the change depends on the amplitude and the period of the forcing, and the ocean structure, while the spatial pattern is independent of these parameters. A simple shallow water model is used to explain these changes. It is found that the term responsible for the enhanced eastward Equatorial jet is the Reynolds stress term, which arises from a phase shift of the zonal current due to friction. The resultant convergence of eastward momentum on the equator and geostrophic adjustment of the interface to the change of zonal current brings about the thermal redistribution of the upper ocean seen in the GCM. 相似文献
19.
冬季婆罗洲岛西北沿岸上升流的时空特征及机理研究 总被引：1，自引：0，他引：1
Winter coastal upwelling off northwest Borneo in the South China Sea(SCS) is investigated by using satellite data, climatological temperature and salinity fields and reanalysis data. The upwelling forms in December, matures in January, starts to decay in February and almost disappears in March. Both Ekman transport induced by the alongshore winter monsoon and Ekman pumping due to orographic wind stress curl are favorable for the upwelling. Transport estimates demonstrate that the month-to-month variability of Ekman transport and Ekman pumping are both consistent with that of winter coastal upwelling, but Ekman transport is two times larger than Ekman pumping in January and February. Under the influence of El Ni?o-Southern Oscillation(ENSO), the upwelling shows remarkable interannual variability: during winter of El Ni?o(La Ni?a) years, an anticyclonic(a cyclonic) wind anomaly is established in the SCS, which behaves a northeasterly(southwesterly) anomaly and a positive(negative) wind stress curl anomaly off the northwest Borneo coast, enhancing(reducing) the upwelling and causing anomalous surface cooling(warming) and higher(lower) chlorophyll concentration. The sea surface temperature anomaly(SSTA) associated with ENSO off the northwest Borneo coast has an opposite phase to that off southeast Vietnam, resulting in a SSTA seesaw pattern in the southern SCS in winter. 相似文献
20.
大亚湾冬季水位的亚潮变化及其与南海的耦合 总被引：1，自引：0，他引：1
本文应用常规时间序列谱分析方法和频域的多输入线性模型研究了冬季广东省大亚湾内水位的亚潮变化及其与大亚湾本地和外海远处各种强迫作用因素间的关系。结果表明：冬季在亚湾亚潮水位的能量主要集中在６．４ｄ和３．６ｄ频带,而在１０．７ｄ频带还有一较弱谱峰,同期广东沿海风的低频能量也主要集中于２－７ｄ频段。造成冬季亚潮水位变化的原因包含了大亚湾本地气象条件的影响,但主要是远地因素作用于大亚湾的结果。外海影响一方 相似文献