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1.
A theoretical problem of linear stationary disturbances of the background geostrophic flow of a stratified rotating medium (atmosphere) that are induced by inhomogeneities of the gravitational field is considered. There is a common belief that such inhomogeneities may only somewhat deform (distort) the state of hydrostatic equilibrium, but cannot affect the dynamics of the flow in the atmosphere. Generally, the problem statement is different for the processes over a solid surface and a water surface, because a water surface (the lower boundary condition for the atmosphere) is deformed by inhomogeneities of the gravitational field. The problem of disturbances over a water surface has been considered in recent papers of the authors; in this paper, the results are developed and significantly revised. The emphasis is on disturbances over a flat horizontal surface, which were not examined before. From the analytical solutions, it follows that the influence of inhomogeneities of the gravitational field on the atmospheric flows may be significant in some cases. Physical generation mechanisms of disturbances are analyzed. 相似文献
2.
SSA_z-1型便携式潮位仪是以计算机控制晶体压力传感器作为水下探头的无井验潮仪,因为探头是放于水下,因此大气压力、水温、盐度、重力加速度、波浪、涌潮、海流等因素的变化都会给潮位测量带来误差,本文论述了上述诸因素给潮位测量带来的影响及提高 SSA_z-1潮位仪精度的措施. 相似文献
3.
A plane problem of free stationary gravitational waves in a horizontal current with vertical shear of the velocity is studied
in the linear statement. The determination of the parameters of waves is reduced to the solution of the Sturm–Liouville boundary-value
problem. For some vertical distributions of current velocity, we obtain analytic solutions. We propose a numerical algorithm
for finding the parameters of waves. On the basis of the performed analysis, we establish the possibility of existence of
stationary surface waves in currents for certain ranges of the Froude number. As the Froude number decreases, the waves become
shorter, which leads to a faster attenuation of waves disturbances with depth. Under the actual conditions, the waves are
short and suffer the influence of shear currents only in the subsurface layer of the ocean. 相似文献
4.
Energetics of lateral eddy diffusion/advection：Part Ⅰ. Thermodynamics and energetics of vertical eddy diffusion 总被引：2，自引：2，他引：0
HUANG Rui Xin 《海洋学报(英文版)》2014,33(3):1-18
Two important nonlinear properties of seawater thermodynamics linked to changes of water density, cabbeling and elasticity(compressibility), are discussed. Eddy diffusion and advection lead to changes in density; as a result, gravitational potential energy of the system is changed. Therefore, cabbeling and elasticity play key roles in the energetics of lateral eddy diffusion and advection. Vertical eddy diffusion is one of the key elements in the mechanical energy balance of the global oceans. Vertical eddy diffusion can be conceptually separated into two steps: stirring and subscale diffusion. Vertical eddy stirring pushes cold/dense water upward and warm/light water downward; thus, gravitational potential energy is increased. During the second steps, water masses from different places mix through subscale diffusion, and water density is increased due to cabbeling. Using WOA01 climatology and assuming the vertical eddy diffusivity is equal to a constant value of 2×103 Pa2/s, the total amount of gravitational potential energy increase due to vertical stirring in the world oceans is estimated at 263 GW. Cabbeling associated with vertical subscale diffusion is a sink of gravitational potential energy, and the total value of energy lost is estimated at 73 GW. Therefore, the net source of gravitational potential energy due to vertical eddy diffusion for the world oceans is estimated at 189 GW. 相似文献
5.
西非被动大陆边缘重力滑脱构造体系下的塑性构造 总被引：3，自引：0，他引：3
论述了西非被动大陆边缘深水环境下的重力滑脱构造体系中的塑性构造。研究发现塑性地层在整个西非被动大陆边缘都有分布,且盐岩塑性层主要分布在西非被动大陆边缘的西南部和西北部,发育层位为过渡期(J-K)构造层之内;中部尼日尔三角洲等塑性层主要为泥岩塑性层,发育层位为古近系和新近系。根据重力滑脱构造体系发育特征可划分为:以正断裂和塑性焊接构造为主的上部重力滑脱伸展构造、以底辟构造为主的中部重力滑脱底辟构造、以冲断裂、塑性褶皱和塑性冲断构造为主的下部重力滑脱冲断构造。根据塑性构造上覆地层的变形过程,塑性构造演化主要经历了后生变形期和同生变形期。塑性构造变形机制主要受基底掀斜作用和上覆地层的沉积速率控制。塑性构造中的底辟、褶皱、冲断及塑性焊接构造对油气成藏的控制作用依次减弱。 相似文献
6.
7.
A. A. Vjatkin A. A. Ivanova V. G. Kozlov K. Yu. Rysin 《Izvestiya Atmospheric and Oceanic Physics》2017,53(2):187-194
Thermal convection in an inclined plane layer having boundaries with different temperatures and rotating around an axis perpendicular to its plane is studied experimentally. It is shown that the convection and heat transfer are determined by two different convective mechanisms—gravitational and thermovibrational ones; they manifest themselves in the threshold excitation of cellular convective structures with different sizes. The thermovibrational convection is caused by the period-averaged mass force arising as a result of tidal oscillations of a nonisothermal fluid with respect to the cavity under the action of the external force-field component tangential to the layer. The map of convection regimes on the plane of governing parameters—the gravitational Rayleigh number and its vibrational analog—has been constructed. It has been found that the thermovibrational convection can develop even in a layer heated from above. The role of the dimensionless velocity of rotation, which has a stabilizing effect on the excitation of both gravitational and thermovibrational convection, has been studied. 相似文献
8.
Multiyear time series obtained by the continuous instrumental monitoring of the electrical activity (EA) of weakly electric
fish Gnathonemus leopoldianus and the motor activity (MA) of the freshwater catfish Hoplosternum thoracatum and the cockroach Blaberus craniifer are compared to the parameters of the lunisolar gravitational tide. These curves are observed to be very similar for a large
number of time intervals. However, a more detailed analysis shows this to be only a superficial resemblance caused by the
closeness of the periods of diurnal and semidiurnal rhythms of bioindicator activity (the dominant rhythms in EA and MA patterns)
and the periods of main gravitational tidal waves. It is concluded that the lunisolar gravitational tide has no significant
effect on animal behavior in our experiment. 相似文献
9.
Analyses of sea level and current-meter data using digital filters and a variety of statistical methods show a variety of phenomena related to non-local coastal forcing and local tidal forcing in the northern reach of San Francisco Bay, a partially mixed estuary. Low-frequency variations in sea level are dominated by non-local variations in coastal sea level and also show a smaller influence from tidally induced fortnightly sea level variations. Low-frequency currents demonstrate a gravitational circulation which is modified by changes in tidal-current speed over the spring-neap tidal cycle. Transients in gravitational circulation induce internal oscillations with periods of two to four days. 相似文献
10.
1 IntroductionThe oceanic general circulation takes place inthe environments of gravity. As a mechanical sys-tem, the oceanic circulation requires sources of me-chanical energy to overcome friction and dissipation.Although the ocean receives a huge amount… 相似文献
11.
Marc-André Gutscher Stephane Dominguez Graham K. Westbrook Pascal Gente Nathalie Babonneau Thierry Mulder Eliane Gonthier Rafael Bartolome Joaquim Luis Filipe Rosas Pedro Terrinha 《Marine and Petroleum Geology》2009,26(5):647-659
The Gulf of Cadiz lies astride the complex plate boundary between Africa and Eurasia west of the Betic-Rif mountain belt. We report on the results of recent bathymetric swathmapping and multi-channel seismic surveys carried out here. The seafloor is marked by contrasting morphological provinces, spanning the SW Iberian and NW Moroccan continental margins, abyssal plains and an elongate, arcuate, accretionary wedge. A wide variety of tectonic and gravitational processes appear to have shaped these structures. Active compressional deformation of the wedge is suggested by folding and thrusting of the frontal sedimentary layers as well as basal duplexing in deeper internal units. There is evidence for simultaneous gravitational spreading occurring upslope. The very shallow mean surface and basal slopes of the accretionary wedge (1° each) indicate a very weak decollement layer, geometrically similar to the Mediterranean Ridge accretionary complex. Locally steep slopes (up to 10°) indicate strongly focused, active deformation and potential gravitational instabilities. The unusual surface morphology of the upper accretionary wedge includes “raft-tectonics” type fissures and abundant sub-circular depressions. Dissolution and/or diapiric processes are proposed to be involved in the formation of these depressions. 相似文献
12.
象山港盐度分布和水体混合 Ⅱ.混合分析 总被引：5，自引：3，他引：2
利用１９８１－１９９０年象山港的实测水文断面资料和盐度通量分析方法定量检验了各种动力因子对象山港水体混合的贡献,探讨了象山港水体混合的控制机理。象山港牛鼻水道至佛渡水道为平流和潮弥散混合区,水体纵向混合较好。象山港狭湾内段的潮混合强度较弱,垂向环流和潮振荡的垂向切变作用突出,水体纵向混合较狭湾外差。象山港湾外段为内段与田外的过渡区,各种混合因子的地位随季节和潮汛而变,水体混合状况介于狭湾内段和口外 相似文献
13.
《Marine Geodesy》2013,36(3-4):399-421
The Jason-1 radar altimeter satellite, launched on December 7, 2001 is the follow on to the highly successful TOPEX/Poseidon (T/P) mission and will continue the time series of centimeter level ocean topography measurements. Orbit error is a major component in the overall error budget of all altimeter satellite missions. Jason-1 is no exception and has set a 1-cm radial orbit accuracy goal, which represents a factor of two improvement over what is currently being achieved for T/P. The challenge to precision orbit determination (POD) is both achieving the 1-cm radial orbit accuracy and evaluating the performance of the 1-cm orbit. There is reason to hope such an improvement is possible. The early years of T/P showed that GPS tracking data collected by an on-board receiver holds great promise for precise orbit determination. In the years following the T/P launch there have been several enhancements to GPS, improving its POD capability. In addition, Jason-1 carries aboard an enhanced GPS receiver and significantly improved SLR and DORIS tracking systems along with the altimeter itself. In this article we demonstrate the 1-cm radial orbit accuracy goal has been achieved using GPS data alone in a reduced dynamic solution. It is also shown that adding SLR data to the GPS-based solutions improves the orbits even further. In order to assess the performance of these orbits it is necessary to process all of the available tracking data (GPS, SLR, DORIS, and altimeter crossover differences) as either dependent or independent of the orbit solutions. It was also necessary to compute orbit solutions using various combinations of the four available tracking data in order to independently assess the orbit performance. Towards this end, we have greatly improved orbits determined solely from SLR+DORIS data by applying the reduced dynamic solution strategy. In addition, we have computed reduced dynamic orbits based on SLR, DORIS, and crossover data that are a significant improvement over the SLR- and DORIS-based dynamic solutions. These solutions provide the best performing orbits for independent validation of the GPS-based reduced dynamic orbits. The application of the 1-cm orbit will significantly improve the resolution of the altimeter measurement, making possible further strides in radar altimeter remote sensing. 相似文献
14.
浙江北部岛屿海域土体稳定性研究 总被引：7，自引：1，他引：7
本文探讨了浙江北部岛屿区水道岸坡土体滑动的成因机制与滑坡的形态特征，对在波浪与重力共同作用下的边坡稳定性以及波浪底压引起的砂土液化进行了定量分析。研究表明，岛屿区水道中部与岸坡间强烈的冲淤反差，是该海域岸坡土体滑动不稳定因素积累的主要环境条件。目前发现的多数为中到大型的牵引式滑坡，主要由重力作用所致。对于波浪较大、水深较浅海域的粉砂、细砂分布区，浅表砂层存在着发生液化的可能性。 相似文献
15.
In this paper, two modified pressure gradient models based on Taylor series expansion are proposed to enhance the higher order source term MPS (MPS-HS) method. The modified models consist of gradient correction matrices applied to the existing (base) pressure gradient models. To validate the modified pressure gradient models first hydrostatic pressure test is simulated and compared to both the base and modified MPS methods. Using the modified models are shown to reduce unphysical pressure oscillations observed in the base models. Second, an evolution of an elliptical drop in a 2D flow field is examined and shown to verify the models. Third, the proposed models illustrated appropriate stability and consistency properties against analytical solutions when an altered gravitational acceleration was superimposed to the hydrostatic pressure test. In addition, an improved performance is observed when Higher order Laplacian (HL) and Error-Compensating Source (ECS) of the Poisson Pressure Equation (PPE) schemes are coupled with the modified pressure gradient models compared to coupling them with the base gradient models. Finally, the modified MPS methods enhanced performances are validated in a free-surface flow simulation for a dam break problem with impact pressure, and a violent sloshing flow in a rectangular tank when compared to the base MPS methods against an existing experimental data. 相似文献
16.
The 1-Centimeter Orbit: Jason-1 Precision Orbit Determination Using GPS, SLR, DORIS, and Altimeter Data 总被引：1，自引：0，他引：1
S. B. Luthcke N. P. Zelensky D. D. Rowlands F. G. Lemoine T. A. Williams 《Marine Geodesy》2003,26(3):399-421
The Jason-1 radar altimeter satellite, launched on December 7, 2001 is the follow on to the highly successful TOPEX/Poseidon (T/P) mission and will continue the time series of centimeter level ocean topography measurements. Orbit error is a major component in the overall error budget of all altimeter satellite missions. Jason-1 is no exception and has set a 1-cm radial orbit accuracy goal, which represents a factor of two improvement over what is currently being achieved for T/P. The challenge to precision orbit determination (POD) is both achieving the 1-cm radial orbit accuracy and evaluating the performance of the 1-cm orbit. There is reason to hope such an improvement is possible. The early years of T/P showed that GPS tracking data collected by an on-board receiver holds great promise for precise orbit determination. In the years following the T/P launch there have been several enhancements to GPS, improving its POD capability. In addition, Jason-1 carries aboard an enhanced GPS receiver and significantly improved SLR and DORIS tracking systems along with the altimeter itself. In this article we demonstrate the 1-cm radial orbit accuracy goal has been achieved using GPS data alone in a reduced dynamic solution. It is also shown that adding SLR data to the GPS-based solutions improves the orbits even further. In order to assess the performance of these orbits it is necessary to process all of the available tracking data (GPS, SLR, DORIS, and altimeter crossover differences) as either dependent or independent of the orbit solutions. It was also necessary to compute orbit solutions using various combinations of the four available tracking data in order to independently assess the orbit performance. Towards this end, we have greatly improved orbits determined solely from SLR+DORIS data by applying the reduced dynamic solution strategy. In addition, we have computed reduced dynamic orbits based on SLR, DORIS, and crossover data that are a significant improvement over the SLR- and DORIS-based dynamic solutions. These solutions provide the best performing orbits for independent validation of the GPS-based reduced dynamic orbits. The application of the 1-cm orbit will significantly improve the resolution of the altimeter measurement, making possible further strides in radar altimeter remote sensing. 相似文献
17.
CHRIS W. HUGHES 《地球，A辑:动力气象学与海洋学》2002,54(1):56-62
A general derivation is given for the torque exerted on a non-spherical planet by a shallow fluid, presenting in a unified form a number of results which are currently scattered through the literature, and deriving those results in a new way. This shows how the sum of gravitational and pressure torques can be rewritten as a 'centrifugal' torque plus a topographic torque due to pressure acting on topography measured relative to the geoid. This clarifies the physics behind the use of spherical coordinate atmosphere and ocean models for calculating torques on the earth. It also shows why the total torque due to the earth's equatorial bulge can be calculated as if it were a pressure torque on an 'effective bulge' of approximately 11 km, the gravitational torque partially offsetting the actual pressure torque on the earth's 21 km bulge. 相似文献
18.
简要回顾了潮汐河口环流、湍流、混合与层化的基本物理概念、内涵、研究方法、研究成果,指出了主要的研究进展,最后,展望了今后的研究方向。本文不考虑悬沙和风浪的影响。经典的河口环流也因潮汐应变的出现而受到挑战,河口环流由重力环流和潮汐应变环流构成。"涡黏度-剪切协方差(ESCO)"概念的提出,又区分出重力ESCO环流与潮汐ESCO环流。横向环流,尤其具有曲率的弯道中的横向环流,也得到进一步的理解。涡度方法的应用,揭示横向环流不仅由各种不同物理机制造成,而且对纵向河口重力环流有重要的影响。分层流中剪切湍流的理论加深了人们对潮汐河口湍流、混合的物理学的认识,势能差异方程更是使得定量理解潮汐河口混合与层化的三维时间、空间变化成为可能。 相似文献
19.
北黄海盆地褶皱分布与成因类型 总被引：1，自引：0，他引：1
北黄海盆地为叠置在华北地台上的中新生代断陷盆地,在地史上经受了多期区域构造运动的改造,地层变形强烈,褶皱构造相当发育,分为伸展型、压缩型、重力型和热力型4大成因类型。其中,与张性正断层相关的伸展型褶皱分布范围最广,可进一步划分为牵引褶皱、逆牵引褶皱、滚动褶皱、翘倾褶皱、补偿性挤压背斜和断层-位移褶皱;形成于区域挤压应力场的压缩型褶皱包括非反转挤压褶皱和反转褶皱,在东部和中部坳陷表现明显;重力型褶皱以发育于古潜山之上的披覆背斜比较常见;由岩浆活动引起的热力型褶皱不甚发育,目前仅见于东部坳陷。 相似文献
20.
A. S. Samodurov 《Physical Oceanography》2006,16(3):129-140
We study the dynamic features of propagation of subsurface gravitational lenses and the conditions of changes in the modes
of control over their motion by various internal and external forces. As these forces, we study the action of drag, molecular
and turbulent viscosity due to the presence of internal and external forces, and deceleration caused by the effects of double
diffusion. We also analyze the modes of propagation of small-scale gravitational lenses. The information about these lenses
taken from the literature is supplemented and generalized.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 3–14, May–June, 2006. 相似文献