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1.
本文讨论了海潮对卫星重力测量的影响问题. 首先介绍了海潮对卫星重力测量影响的基本理论；采用FES02和TPXO6海潮模型计算了海潮负荷对卫星重力结果前60阶的影响；并用两个模型之间的差异作为海潮模型精度的估计量，据此计算了海潮模型误差对卫星重力结果的影响. 与GRACE恢复的重力场精度的比较说明：海潮对重力场40阶以下的影响都超过了目前重力场恢复精度；尽管由于卫星测高技术的发展，海潮模型的精度有了很大的提高，但目前的全球海潮模型用于GRACE重力场恢复的前12阶的改正还是不够精确. 另外，我们也利用中国东海和南海潮汐资料以及FES02海潮模型讨论了中国近海潮汐效应对GRACE观测的影响. 结果说明该影响与海潮模型的误差相当. 这反映了当前海潮模型的不确定度，因此通过结合全球验潮站资料有望提高海潮对卫星重力测量的改正精度. 相似文献
2.
Using data on wind stress, significant height of combined wind waves and swell, potential temperature, salinity and seawater velocity, as well as objectively-analyzed in situ temperature and salinity, we established a global ocean dataset of calculated wind- and tide-induced vertical turbulent mixing coefficients. We then examined energy conservation of ocean vertical mixing from the point of view of ocean wind energy inputs, gravitational potential energy change due to mixing (with and without artificially limiting themixing coefficient), and K-theory vertical turbulent parameterization schemes regardless of energy inputs. Our research showed that calculating the mixing coefficient with average data and artificial limiting the mixing coefficient can cause a remarkable lack of energy conservation, with energy losses of up to 90% and changes in the energy oscillation period. The data also show that wind can introduce a huge amount of energy into the upper layers of the Southern Ocean, and that tidesdo so in regions around underwater mountains. We argue that it is necessary to take wind and tidal energy inputs into account forlong-term ocean climate numerical simulations. We believe that using this ocean vertical turbulent mixing coefficient climatic dataset is a fast and efficient method to maintain the ocean energy balance in ocean modeling research. 相似文献
3.
本文分析了投弃式海流电场剖面仪的发展,简介了海流感生电场的基本原理,提出了投弃式海流电场剖面仪的技术方案.根据投弃式海流电场剖面仪的实际需求,研发了XCP海流电场传感器,并通过XCP探头的自旋转(16 r/s),实现了将海流电场信号AM调制并频移至海流电场传感器的超低噪声频段,解决了在高噪声背景下快速测量纳伏级微弱海流电场信号.设计实现了XCP探头前端弱信号处理电路,对海流电场微弱信号进行滤波提取的同时可实现对海流电场同向分量进行硬件电路补偿,在一定程度上克服了XCP探头下沉引起感生电场的强干扰.在XCP探头内部采用SoPC技术实现对海流电场信号、罗盘线圈信号和温度信息的快速测量及其数字化处理,并将数字信息以UART协议及LVDS物理层数传方式发送到XCP浮筒端.开创了长度2 km、直径0.1 mm漆包线动态数据传输技术,解决了XCP探头和XCP浮筒之间的数字化数据传输问题.根据XCP探头所采集的海流电场信号与罗盘线圈信号的同相分量In、正交分量Qn、基线量Bn数据,研究了XCP探测方法,从而计算出了海流的东向与北向相对速度分量VEr、VNr.采用所研发的XCP,在我国南海海域首次采集到海面至海下千米深度的XCP海流电场信息和海洋温度信息. 相似文献
4.
利用Farrell模式，结合烟台海洋洁潮汐，估算了海潮对烟台地倾斜、伸缩仪观测影响的量值。有了这一数据，就可以根据烟台的海潮观测资料对地倾斜、伸缩仪观测资料进行海潮影响的改正。 相似文献
5.
Nicolas Reul Severine Fournier Jaqueline Boutin Olga Hernandez Christophe Maes Bertrand Chapron Gaël Alory Yves Quilfen Joseph Tenerelli Simmon Morisset Yann Kerr Susanne Mecklenburg Steven Delwart 《Surveys in Geophysics》2014,35(3):681-722
While it is well known that the ocean is one of the most important component of the climate system, with a heat capacity 1,100 times greater than the atmosphere, the ocean is also the primary reservoir for freshwater transport to the atmosphere and largest component of the global water cycle. Two new satellite sensors, the ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Aquarius SAC-D missions, are now providing the first space-borne measurements of the sea surface salinity (SSS). In this paper, we present examples demonstrating how SMOS-derived SSS data are being used to better characterize key land–ocean and atmosphere–ocean interaction processes that occur within the marine hydrological cycle. In particular, SMOS with its ocean mapping capability provides observations across the world’s largest tropical ocean fresh pool regions, and we discuss from intraseasonal to interannual precipitation impacts as well as large-scale river runoff from the Amazon–Orinoco and Congo rivers and its offshore advection. Synergistic multi-satellite analyses of these new surface salinity data sets combined with sea surface temperature, dynamical height and currents from altimetry, surface wind, ocean color, rainfall estimates, and in situ observations are shown to yield new freshwater budget insight. Finally, SSS observations from the SMOS and Aquarius/SAC-D sensors are combined to examine the response of the upper ocean to tropical cyclone passage including the potential role that a freshwater-induced upper ocean barrier layer may play in modulating surface cooling and enthalpy flux in tropical cyclone track regions. 相似文献
6.
大陆上用重力数据和GPS水准数据确定(似)大地水准面,海洋上用卫星测高数据确定(似)大地水准面.由于沿海地区和近岸海域往往缺少完好的重力数据,近岸海域卫星测高数据质量相对较差,两类大地水准面在陆海相接区域精度偏低且存在拼合差.纯几何方法拟合陆海局部区域大地水准面,不能顾及大地水准面的物理特性,拟合结果不稳定.顾及到大地水准面的物理特性,依据其在局部所应满足的数学物理方程,拟合陆海局部区域大地水准面问题,转化为Laplace第一边值问题.讨论了有限元法衔接陆海局部区域大地水准面的数学思想,给出了相应的数学模型. 相似文献
7.
Estimation of ocean circulation is investigated via assimilation of satellite measurements of the dynamic ocean topography (DOT) into the global finite-element ocean model (FEOM). The DOT was obtained by means of a geodetic approach from carefully cross-calibrated multi-mission altimeter data and GRACE gravity fields. The spectral consistency was achieved by consistently filtering both, the sea surface and the geoid. The filter length is determined by the spatial resolution of the gravity field and corresponds to approximately 241 km half width for the GRACE-based gravity field model ITG-Grace03s.The assimilation of the geodetic DOT was performed by employing a local singular evolutive interpolated Kalman (SEIK) filter in combination with the method of weighting of observations. It is shown that this approach leads to a successful assimilation technique that reduced the RMS difference between the model and the data from 16 cm to 5 cm during one year of assimilation. The ocean model returns an optimized mean dynamic ocean topography. The effects of assimilation on transport estimates across several hydrographic World Ocean Circulation Experiment (WOCE) sections show improvements compared to the FEOM run without data assimilation. As a result of the assimilation, DOT estimates are available in the polar or coastal regions where the geodetic estimates from satellite data alone are not adequate. Furthermore, more realistic features of the ocean can be seen in these areas compared to those obtained using the filtered data fields. 相似文献
8.
Ocean Dynamics - The input of mechanical power to the ocean due to the surface wind stress, in regions which correspond to different regimes of ocean dynamics, is considered using data from... 相似文献
9.
Besides providing an estimate of the changing ocean state, an important result of the dynamically consistent estimating the circulation and climate of the ocean (ECCO) state estimate approach is the provision of a posterior model–data residuals which contain important information about elements in the assimilated observations that are inconsistent with the model dynamics or with the information present in other ocean data sets that are being used as constraints in the assimilation procedure. Based on decreased GECCO2 model–data residuals, upon using the altimeter data through the ESA climate change initiative (cci) sea-level (SL) project, we show here that the recently reprocessed ESA SL_cci altimeter data set (SL1) has been improved relative to the earlier AVISO altimetry data set and is now more consistent with the GECCO2 estimate and with the information about the changing ocean state embedded in other ocean data sets. The improvement can be shown to exist separately for both TOPEX/POSEIDON and ERS data sets. The study reveals that especially in regions characterized by small sea surface height (SSH) variability and small signal-to-noise ratio in the SSH data, improvements can be on the order of 30% of previously existing model–data residuals. However, in some regions we can find degradations, particulary in those where GECCO2 has little skill in representing the altimeter data and where evaluation of the products with GECCO2 is thus not advisable. Upon the assimilation of the new SL1 data set, the GECCO2 synthesis was further improved. However, adding the sea surface temperature (SST) from the SST_cci project as additional constrain, no further impact can be identified. 相似文献
10.
Traditionally, ocean tides have been modeled in frequency domain with a forcing from selected tidal constituents. It is a natural approach; however, it implicitly neglects non-linearities of ocean dynamics. An alternative approach is time-domain modeling with a forcing given by the full lunisolar potential, i.e., all tidal waves are a priori included. This approach has been applied in several ocean tide models; however, some challenging tasks still remain, for example, assimilation of satellite altimetry data. In this paper, we introduce the assimilative scheme applicable in a time-domain model, which is an alternative to existing techniques used in assimilative ocean tide models. We present results from DEBOT, a global barotropic ocean tide model, which has two modes: DEBOT-h, a purely hydrodynamical mode, and DEBOT-a, an assimilative mode. The accuracy of DEBOT in both modes is assessed through a series of tests against tide gauge data which demonstrate that DEBOT is comparable to state-of-the-art global ocean tide models for major tidal constituents. Furthermore, as signals of all tidal frequencies are included in DEBOT, we also discuss modeling of minor tidal constituents and non-linear compound tides. Our modeling approach can be useful for those applications where the frequency domain approach is not suitable. 相似文献
11.
Summary Procedures of astrodynamics are used to calculate the actual values of the secular variation of the inclination and eccentricity of the Moon's orbit due to ocean tides. The ocean tide data were taken from the resolution of the ocean tide potential into spherical functions[2] based on cotidal maps[1]. 相似文献
12.
Observation-based evaluation of surface wave effects on currents and trajectory forecasts 总被引：4，自引：2，他引：2
Johannes R?hrs Kai H?kon Christensen Lars Robert Hole G?ran Brostr?m Magnus Drivdal Svein Sundby 《Ocean Dynamics》2012,62(10-12):1519-1533
Knowledge of upper ocean currents is needed for trajectory forecasts and is essential for search and rescue operations and oil spill mitigation. This paper addresses effects of surface waves on ocean currents and drifter trajectories using in situ observations. The data set includes colocated measurements of directional wave spectra from a wave rider buoy, ocean currents measured by acoustic Doppler current profilers (ADCPs), as well as data from two types of tracking buoys that sample the currents at two different depths. The ADCP measures the Eulerian current at one point, as modelled by an ocean general circulation model, while the tracking buoys are advected by the Lagrangian current that includes the wave-induced Stokes drift. Based on our observations, we assess the importance of two different wave effects: (a) forcing of the ocean current by wave-induced surface fluxes and the Coriolis–Stokes force, and (b) advection of surface drifters by wave motion, that is the Stokes drift. Recent theoretical developments provide a framework for including these wave effects in ocean model systems. The order of magnitude of the Stokes drift is the same as the Eulerian current judging from the available data. The wave-induced momentum and turbulent kinetic energy fluxes are estimated and shown to be significant. Similarly, the wave-induced Coriolis–Stokes force is significant over time scales related to the inertial period. Surface drifter trajectories were analysed and could be reproduced using the observations of currents, waves and wind. Waves were found to have a significant contribution to the trajectories, and we conclude that adding wave effects in ocean model systems is likely to increase predictability of surface drifter trajectories. The relative importance of the Stokes drift was twice as large as the direct wind drag for the used surface drifter. 相似文献
13.
R&#;hrs Johannes Christensen Kai H&#;kon Hole Lars Robert Brostr&#;m G&#;ran Drivdal Magnus Sundby Svein 《Ocean Dynamics》2012,62(10):1519-1533
Knowledge of upper ocean currents is needed for trajectory forecasts and is essential for search and rescue operations and oil spill mitigation. This paper addresses effects of surface waves on ocean currents and drifter trajectories using in situ observations. The data set includes colocated measurements of directional wave spectra from a wave rider buoy, ocean currents measured by acoustic Doppler current profilers (ADCPs), as well as data from two types of tracking buoys that sample the currents at two different depths. The ADCP measures the Eulerian current at one point, as modelled by an ocean general circulation model, while the tracking buoys are advected by the Lagrangian current that includes the wave-induced Stokes drift. Based on our observations, we assess the importance of two different wave effects: (a) forcing of the ocean current by wave-induced surface fluxes and the Coriolis–Stokes force, and (b) advection of surface drifters by wave motion, that is the Stokes drift. Recent theoretical developments provide a framework for including these wave effects in ocean model systems. The order of magnitude of the Stokes drift is the same as the Eulerian current judging from the available data. The wave-induced momentum and turbulent kinetic energy fluxes are estimated and shown to be significant. Similarly, the wave-induced Coriolis–Stokes force is significant over time scales related to the inertial period. Surface drifter trajectories were analysed and could be reproduced using the observations of currents, waves and wind. Waves were found to have a significant contribution to the trajectories, and we conclude that adding wave effects in ocean model systems is likely to increase predictability of surface drifter trajectories. The relative importance of the Stokes drift was twice as large as the direct wind drag for the used surface drifter.
相似文献14.
In this study, we have estimated the different sea level components (observed sea level from satellite altimetry, steric sea
level from in situ hydrography—including Argo profiling floats, and ocean mass from Gravity Recovery and Climate Experiment;
GRACE), in terms of regional and interannual variability, over 2002–2009. We compute the steric sea level using different
temperature (and salinity) data sets processed by different groups (SCRIPPS, CLS, IPRC, and NOAA) and first focus on the regional
variability in steric and altimetry-based sea level. In addition to El Nino–La Nina signatures, the observed and steric sea
level data show clear impact of three successive Indian Ocean Dipoles in 2006, 2007, and 2008 in the Indian Ocean. We next
study the spatial trend patterns in ocean mass signal by comparing GRACE observations over the oceans with observed minus
steric sea level. While in some regions, reasonably good agreement is observed, discrepancy is noticed in some others due
to still large regional trend errors in Argo and GRACE data, as well as to a possible (unknown) deep ocean contribution. In
terms of global mean, interannual variability in altimetry-based minus steric sea level and GRACE-based ocean mass appear
significantly correlated. However, large differences are reported when short-term trends are estimated (using both GRACE and
Argo data). This prevents us to draw any clear conclusion on the sea level budget over the recent years from the comparison
between altimetry-based, steric sea level, and GRACE-based ocean mass trends, nor does it not allow us to constrain the Glacial
Isostatic Adjustment correction to apply to GRACE-based ocean mass term using this observational approach. 相似文献
15.
本文利用卫星重力、卫星测高和海洋温盐数据反演计算全球海水质量变化,并分析其时空变化特征.卫星重力数据利用2003年1月~2006年12月的GRACE月时变重力场球谐系数,同时考虑替换一阶项和C20项,并进行了相关误差滤波、高斯滤波和陆地水文信号泄漏改正,计算得到海洋等效水高变化;利用相同时间跨度的卫星测高数据和海洋温度、盐度水文观测数据,计算全球海平面变化和比容海平面变化,反演得到海水质量变化.反演的两种海水质量变化的年际变化特征一致性较好.三种数据得到的长期趋势变化,与1993~2003年的结果相比,可以看出,海水质量变化加速,并已成为全球海平面上升的主要因素. 相似文献
16.
In order to predict the behaviour of plumes from three deep ocean outfalls for sewage off Sydney, three-dimensional numerical modelling was used. The modelling suite was driven by data generated by an oceanographic monitoring station measuring wind, ocean currents, temperature and wave characteristics. Three different modelling phases are implemented daily, a nearfield model, a hydrodynamic model and a water quality model. Model output can be used by the New South Wales Environment Protection Authority to predict water quality at ocean beaches and inform the community. 相似文献
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Super Typhoon Haiyan devastated portions of Southeast Asia, particularly the Philippines, on November 8, 2013. In this paper, observational data are used to analyze the intensification process of Super Typhoon Haiyan. Observational data showed that Typhoon Haiyan intensified and the maximum sustained winds increased to 59 ms?1 after it encountered a double warm-core ocean eddy, while the central pressure of the typhoon dropped from 970 hPa to 920 hPa. Numerical simulations and observational data show that the presence of the warm-core eddy combined with SST increases due to climate change led to the rapid intensification of Super Typhoon Haiyan. Comparing these two factors, the warm-core ocean eddy, which brings significantly more heat into the upper ocean, plays the leading role in the intensification, with climate warming making a lesser contribution. Moreover, due to the increased thickness of the mixed layer associated with the warm-core ocean eddy, Super Typhoon Haiyan did not significantly decrease the sea surface temperature to the east of the Philippines, as is typical of typhoons, and the largest decrease was approximately 1 °C. 相似文献
20.
Avellaneda PM Englehardt JD Olascoaga J Babcock EA Brand L Lirman D Rogge WF Solo-Gabriele H Tchobanoglous G 《Marine pollution bulletin》2011,62(10):2157-2169
A relative risk assessment of biosolids disposal alternatives for cruise ships is presented in this paper. The area of study encompasses islands and marine waters of the Caribbean Sea. The objective was to evaluate relative human health and ecological risks of (a) dewatering/incineration, (b) landing the solids for disposal, considering that in some countries land-disposed solids might be discharged in the near-shore environment untreated, and (c) deep ocean disposal. Input to the Bayesian assessment consisted of professional judgment based on available literature and modeling information, data on constituent concentrations in cruise ship biosolids, and simulations of constituent concentrations in Caribbean waters assuming ocean disposal. Results indicate that human health and ecological risks associated with land disposal and shallow ocean disposal are higher than those of the deep ocean disposal and incineration. For incineration, predicted ecological impacts were lower relative to deep ocean disposal before considering potential impacts of carbon emissions. 相似文献