共查询到20条相似文献，搜索用时 15 毫秒
1.
In this study a new approach for reconstructing the Mean Dynamic Topography of the Black Sea is applied. Constant observations (SVP measurements), drifters, and data of vertical sounding of the temperature and salt content together with measurements of sea level anomalies received from Topex/Poseidon mission satellite data were used. The absolute sea level received by altimetry data using the mean dynamic topography received during work was compared to the dynamic level received according to independent marine surveys. The comparison showed that the method represented in the study permits one to define more exactly the dynamic topography of the Black Sea when compared with the studies of previous authors. The results of this study will be useful to reconstruct the areas of the geostrophic currents according to satellite altimetry. 相似文献
2.
The Black Sea dynamics for two decades (1993–2012) is analyzed. The study is carried out in numerical simulation with the use of a circulation model and assimilation of satellite measurements of free surface elevations and sea-surface temperatures (SSTs). The Black Sea circulation model has a spatial resolution of 4.8 km and 35 vertical levels, which thicken toward the surface. Arrays of ERA-Interim data are used for simulating the atmospheric forcing. A set of 3D arrays of the Black Sea hydrophysical fields is calculated on a regular grid with a time resolution of 24 h. The results are analyzed and compared with available contact measurements of temperature and salinity. This comparison shows a quite good quality of the resulted hydrophysical fields of the Black Sea. 相似文献
3.
Mesoscale surface circulation and variability of Southern Indian Ocean derived by combining satellite altimetry and drifter observations 总被引：1，自引：1，他引：0
BENNY N. Peter SHENBAKAVALLI Ranjan MAZLAN Hashim MOHD Nadzri Re MOHD Razali Mahmud 《海洋学报(英文版)》2015,34(9):12-22
High resoultion Eulerian mean velocity field has been derived by combining the satellite tracked surface drifter data with satellite altimetry and ocean surface winds. The drifter data used in this study includes Argos and surface drifter data from Global Drifter Program. Maps of Sea Level Anomaly(MSLA) weekly files with a resolution of(1/3)° in both Latitude and Longitude for the period 1993–2012 have been used. The Ekman current is computed using ocean surface mean wind fields from scatterometers onboard ERS 1/2,Quikscat and ASCAT. The derived mean velocity field exhibits the broad flow of Antarctic Circumpolar Current with speeds up to 0.6 m/s.Anomalous field is quite significant in the western part between 20° and 40°E and in the eastern part between 80°E and 100°E with velocity anomaly up to 0.3 m/s. The estimated mean flow pattern well agrees with the dynamic topography derived from in-situ observations. Also,the derived velocity field is consistent with the in-situ ADCP current measurements. Eddy kinetic energy illustrates an increasing trend during 1993–2008 and is in phase coherence with the Southern Annular Mode by three month lag. Periodic modulations are found in the eddy kinetic energy due the low frequency Antarctic Circumpolar Wave propagation. 相似文献
4.
G. K. Korotaev P. N. Lishaev V. V. Knysh 《Izvestiya Atmospheric and Oceanic Physics》2016,52(9):961-973
The methodology of joint processing of the satellite altimetry and occasional hydrological observations in the Black Sea for 1993–2012 is developed. The original technique for reconstruction of the 3D temperature and salinity fields in the deep-sea part is proposed and implemented. This technique makes it possible to identify the depths at which a contribution of adiabatic processes to the deformation of the temperature and salinity profiles of the sea is predominant. Daily-averaged 3D fields of the seawater temperature and salinity in a baroclinic layer on a regular grid are reconstructed. The evaluation of accuracy of the reconstructed temperature and salinity arrays is performed by comparing them with the data of hydrological exploration. Structures of the temperature and salinity fields are correlated naturally with topography of the altimetric level and clearly indicate the synoptic variability. Seasonal and interannual variabilities of the kinetic energy (averaged over horizons of the 63–400 m layer) of the geostrophic currents calculated using the dynamic method makes it possible to reveal a sharp increase in the kinetic energy of the currents in the winter season of 2002. A high correlation is found between the interannual variability of the ERA-Interim wind stress curl averaged over the surface of the deep sea part and the kinetic energy of the geostrophic currents in the 63–400 m layer. 相似文献
5.
Surface velocities determined from trajectory of a drifting buoy from March through November 1987 are compared with surface geostrophic velocities determined from sea surface dynamic topography (SSDT) obtained from altimetry data with the aid of long-term hydrographic observation data. In general, these velocities show similar temporal variations in both zonal and meridional components, except in a period when obvious error is found in the altimetric SSDT field. When the buoy was trapped by several mid-ocean meso-scale eddies, the comparison is especially good. Systematic discrepancy is found, however, when the buoy was in the Kuroshio region, because of using both temporally and spatially smoothed mean SSDT estimated from hydrographic data; instead, surface geostrophic velocities determined from the altimetric SSDT referred to the improved geoid model result in better comparison. 相似文献
6.
由于卫星高度计数据分辨率高、观测范围广的特点，我们使用该数据开展了黑潮流的研究。在之前的研究中，卫星绝对地转流都被用于对黑潮流域的表层流场的时空变化特征进行研究，并采用了一些探测方法提取了黑潮流轴和流路。然而，海面绝对地转流是由绝对动力地形估计得到，应该被当做实际流场的地转分量，在实际应用中并不能代表真实流场。在本研究中，建立了气候态绝对地转流与网格平均的漂流浮标流场间的数学校验关系，以此对卫星绝对地转流场进行修正，即便这两种数据的性质存在些许偏差。因此，基于主成分探测法，修正后的卫星绝对地转流被用于探测黑潮流轴和流路。对比结果表明，由修正后的卫星地转流场探测得到的黑潮流轴和流路均要好于地转流和表层流估计结果。修正后的地转流有助于开展更加准确的黑潮流轴和流路的逐日探测。 相似文献
7.
Detecting fluctuations of the Kuroshio axis south of Japan using TOPEX/POSEIDON altimeter data 总被引：1，自引：0，他引：1
Shiro Imawaki Mayumi Gotoh Hiroyuki Yoritaka Noriya Yoshioka Atsunobu Misumi 《Journal of Oceanography》1996,52(1):69-92
Sea surface dynamic topography (SSDT) can be divided into temporal mean SSDT and fluctuation SSDT. The former is approximated with a climatological mean SSDT and the latter is derived from satellite altimetry data, to give an approximated total SSDT (called a composite SSDT). The method is applied to detecting fluctuations of the Kuroshio axis south of Japan using TOPEX/POSEIDON altimeter data from the first year mission in 1992–1993. The fluctuation SSDT averaged over a wide area south of Japan clearly shows an annual cycle with an amplitude of about 15 cm. Temporal changes of SSDT along a subsatellite track crossing the Kuroshio compare moderately well with those estimated from repeated hydrographic observations, although there is a discrepancy of unknown origin. The composite SSDT also compares well with SSDT estimated from the same hydrographic data. Horizontal distribution of the surface geostrophic velocity component normal to subsatellite tracks is derived every ten days from the composite SSDT. Most locations of estimated strong eastward geostrophic velocities coincide well with locations of the Kuroshio axis determined every 15 days fromin situ surface velocity measurements on various vessels; for example, a fairly large meander of the Kuroshio south of Honshu is clearly detected. It is concluded that the composite SSDT can be used reliably to detect fluctuations of the Kuroshio axis south of Japan. 相似文献
8.
Yu. B. Ratner A. P. Tolstosheev A. L. Kholod S. V. Motyzhev 《Physical Oceanography》2009,19(3):170-185
We consider some specific features of creation of the database according to the results of drifter experiments carried out
in the Black Sea in 2001–2006. The general statistical information on all buoy studies in the sea is presented. The criteria
used to filter the primary data are suggested. The principles of formation and structuring of the drifter database are presented.
As an example, we describe the procedure and the results of comparison of model estimates with the data of contact measurements
of the sea-surface temperature by drifting buoys. 相似文献
9.
Wenyan Sui Junru Guo Jun Song Zhiliang Liu Meng Wang Xibin Li Yanzhao Fu Yongquan Li Yu Cai Linhui Wang Lingli Li Xiaofang Guo Wenting Zuo 《海洋学报(英文版)》2021,40(3):142-152
The new gravity field models of gravity field and steady-state ocean circulation explorer(GOCE), TIM_R6 and DIR_R6, were released by the European Space Agency(ESA) in June 2019. The sixth generation of gravity models have the highest possible signal and lowest error levels compared with other GOCE-only gravity models, and the accuracy is significantly improved. This is an opportunity to build high precision geostrophic currents. The mean dynamic topography and geostrophic currents have been calculated by the 5 th(TIM_R5 and DIR_R5), 6 th(TIM_R6 and DIR_R6) release of GOCE gravity field models and ITSG-Grace2018 of GRACE gravity field model in this study. By comparison with the drifter results, the optimal filtering lengths of them have been obtained(for DIR_R5, DIR_R6, TIM_R5 and TIM_R6 models are 1° and for ITSG-Grace2018 model is 1.1°). The filtered results show that the geostrophic currents obtained by the GOCE gravity field models can better reflect detailed characteristics of ocean currents. The total geostrophic speed based on the TIM_R6 model is similar to the result of the DIR_R6 model with standard deviation(STD) of 0.320 m/s and 0.321 m/s, respectively. The STD of the total velocities are 0.333 m/s and 0.325 m/s for DIR_R5 and TIM_R5. When compared with ITSG-Grace2018 results, the STD(0.344 m/s) of total geostrophic speeds is larger than GOCE results, and the accuracy of geostrophic currents obtained by ITSG-Grace2018 is lower. And the absolute errors are mainly distributed in the areas with faster speeds, such as the Antarctic circumpolar circulation, equatorial region, Kuroshio and Gulf Stream areas. After the remove-restore technique was applied to TIM_R6 MDT, the STD of total geostrophic speeds dropped to 0.162 m/s. 相似文献
10.
To study the long-term variability of the thermohaline and dynamic characteristics of the Black Sea, we use three versions
of climatic fields, namely, the fields reconstructed in the model according to the old (1903–1982) and new (1903–2003) hydrological
climatic data arrays of temperature and salinity and according to the data of satellite altimetry. The analysis of the altimetry-based
climatic fields confirms the distinctions (established earlier according to the old and new data arrays) in the seasonal variability
of the integral characteristics of temperature and salinity and in the structures of hydrophysical fields in the sea. It is
shown that, in the winter-spring season, the thermohaline fields reconstructed according to the new and altimetry data arrays
are characterized by a small elevation of the halocline (pycnocline) and the upper boundary of the cold intermediate layer.
In all seasons, the altimetry-based surface geostrophic currents contain numerous mesoscale eddies with different signs of
rotation. Moreover, in all seasons, the Rim Current reconstructed according to the altimetry data is characterized by a narrower
jet almost along the entire its length. This jet is especially intense near the coasts of West Anatolia.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 3–17, July–August, 2006. 相似文献
11.
The effect of mesoscale eddy variability on the Japan/East Sea mean circulation is examined from satellite altimeter data
and results from the Naval Research Laboratory Layered Ocean Model (NLOM). Sea surface height variations from the Geosat-Exact
Repeat Mission and TOPEX/POSEIDON altimeter satellites imply geostrophic velocities. At the satellite crossover points, the
total velocity and the Reynolds stress due to geostrophic mesoscale turbulence are calculated. After spatial interpolation
the momentum flux and effect on geostrophic balance indicates that the eddy variability aids in the transport of the Polar
Front and the separation of the East Korean Warm Current (EKWC). The NLOM results elucidate the impact of eddy variability
on the EKWC separation from the Korean coast. Eddy variability is suppressed by either increasing the model viscosity or decreasing
the model resolution. The simulations with decreased eddy variability indicate a northward overshoot of the EKWC. Only the
model simulation with sufficient eddy variability depicts the EKWC separating from the Korean coast at the observed latitude.
The NLOM simulations indicate mesoscale influence through upper ocean-topographic coupling.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
Development of means and methods of drifter technology applied to the problem of the Black Sea research 总被引：1，自引：0，他引：1
During the last ten years, autonomous drifting platforms for data collection (drifters) equipped with Argos satellite communication devices have become one of the main components for the observation system in the upper layer of the ocean and surface atmosphere. This article presents the results of the Black Sea drifter monitoring in 2002–2006 within a number of international programs and projects. During this period, about 70 drifters manufactured by NPF Marlin-Yug Ltd. (Sevastopol, Ukraine) were deployed in the western part of the Black Sea. The drifters were mainly standard barometric Lagrangian tracers and a part of them were principally new temperature profiling buoys. Unique long-term data were obtained about the circulation of the surface currents and the dynamics of the temperature stratification within the seasonal thermocline and the cold intermediate layer. 相似文献
13.
For the first time, an acoustic Doppler current profiler (ADCP) produced by the RDI is used in the water area of the Black
Sea in the lowered mode. This direction in the application of acoustic Doppler current profilers is now in the stage of development
and verification of various procedures of measurements with subsequent data processing and enables one to get the distributions
of current velocities down to depths of 1000–6000 m depending on the modification of the instrument. We describe the procedures
of measurements performed with the help of the ADCP in the lowered mode in the course of an expedition and the stages of processing
of the primary data based on the experience of application of similar acoustic current profilers at the Marine Hydrophysical
Institute of the Ukrainian National Academy of Sciences accumulated in the 1980s. We generalize the experience of application
of ADCP under the hydrological conditions of the Black Sea, propose the algorithms of data processing, present the profiles
of absolute current velocity at several stations, compare these profiles with the geostrophic velocities, and determine the
deep-water structure of the field of currents in a shelf-open-sea section made along 31.17°E.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 31–48, July–August, 2006. 相似文献
14.
Izvestiya, Atmospheric and Oceanic Physics - A study of water circulation in the northwestern part of the Bering Sea using AVISO satellite data on velocities of geostrophic currents from 2002 to... 相似文献
15.
稳态海面地形(MDT)是大地测量学家和海洋学家共同关心的一个重要物理量。该文基于WHU2009全球平均海面高模型和GO_CONS_GCF_2_TIM_R3纯GOCE重力场模型,采用几何法经高斯滤波处理后确定了全球稳态海面地形,与CLS09及DTU10M DTs相比,其差值均方根RMS均小于8 cm,表明该文结果具有较高的精度;根据地转流方程计算了相应的表层地转流,与GRACE重力场模型GGM03S结果相比,GOCE重力场模型所确定的表层地转流在墨西哥湾流、黑潮及厄加勒斯海流等海域均体现了更强的流速和更多的细部特征,验证了GOCE在洋流探测中的优势。 相似文献
16.
17.
Variability of Sea Surface Circulation in the Japan Sea 总被引：3，自引：0，他引：3
Composite sea surface dynamic heights (CSSDH) are calculated from both sea surface dynamic heights that are derived from altimetric data of ERS-2 and mean sea surface that is calculated by a numerical model. The CSSDH are consistent with sea surface temperature obtained by satellite and observed water temperature. Assuming the geostrophic balance, sea surface current velocities are calculated. It is found that temporal and spatial variations of sea surface circulation are considerably strong. In order to examine the characteristics of temporal and spatial variation of current pattern, EOF analysis is carried out with use of the CSSDH for 3.5 years. The spatial and temporal variations of mode 1 indicate the strength or weakness of sea surface circulation over the entire Japan Sea associated with seasonal variation of volume transport through the Tsushima Strait. The spatial and temporal variations of mode 2 mostly indicate the temporal variation of the second branch of the Tsushima Warm Current and the East Korean Warm Current. It is suggested that this variation is possibly associated with the seasonal variation of volume transport through the west channel of the Tsushima Strait. Variations of mode 3 indicate the interannual variability in the Yamato Basin. 相似文献
18.
19.
Comparative analysis of the North Atlantic surface circulation reproduced by three different methods
K. V. Lebedev A. S. Sarkisyan O. P. Nikitin 《Izvestiya Atmospheric and Oceanic Physics》2016,52(4):410-417
Calculation results are presented for long-term mean annual surface currents in the North Atlantic based on direct drifter measurements and numerical experiments with the ocean general circulation model using both climatic arrays of hydrological data World Ocean Atlas 2009 and Argo profiling data. The calculations show that the technique suggested for model calculations of oceanographic characteristics of the World Ocean with the use of Argo data significantly improves the climatic fields of the temperature and salinity even on a coarse grid. The comparison of the model calculation results with drifter data showed that the temperature and salinity fields found from Argo data with the use of data variational interpolation on a regular grid allow the calculation of realistic currents and can be successfully used as initial conditions in hydrodynamic models of the ocean dynamics. 相似文献
20.
利用西北印度洋船测数据评估基于卫星的海表面温度 总被引：1，自引：1，他引：0
本文描述了一次夏季在西北印度洋进行的调查船水文测量,用船测数据评估卫星海面表温度,并寻找影响海表面温度误差的主要因素。我们考虑了两种卫星数据,第一种是微波遥感产品——热带降雨测量任务微波成像仪TMI数据,另外一种是融合了微波,红外线,以及少部分观测数据的融合数据产品——可处理海表温度和海冰分析OSTIA数据。结果表明融合数据的日平均海表面温度的平均误差和均方根误差都比微波遥感小。这一结果证明了融合红外线遥感,微波遥感以及观测数据来提高海表面温度数据质量的必要性。此外,我们分析了海表面温度误差与各项水文参数之间的相关关系,包括风速,大气温度,想对湿度,大气压力,能见度。结果表明风速与TMI海表面温度误差的相关系数最大。而大气温度是影响OSTIA海表面温度误差最重要的因素;与此同时,想对湿度与海表面温度误差的相关系数也很高。 相似文献