共查询到20条相似文献，搜索用时 828 毫秒
1.
V. F. Ivanov 《Physical Oceanography》1990,1(5):369-376
Taking into consideration stratification, the mean current velocity, and the tangential wind stress expressed in terms of air pressure fluctuations, we have derived iteration formulae and have performed computations of the amplitudinal characteristics of oceanic internal waves generated by air pressure waves of semi-diurnal and 4-day long periodicity propagating over the Tropical Atlantic Ocean. It has been demonstrated that such periodicity and wavelengths may contribute to the generation of long-amplitude internal waves, whose intensity is largely dependent on the direction of atmospheric wave propagation.Translated by Vladimir A. Puchkin. 相似文献
2.
A plane problem of generation of barotropic seiches in a bounded rotating basin by traveling atmospheric fronts is studied
within the framework of the linear theory of long waves. The front is characterized by disturbances of the baric field and
the corresponding field of tangential wind stresses. We deduce the modified Ackerblom formulas for the wind stresses according
to the given anomalies of atmospheric pressure in which the uniform transport of disturbances of the baric field is taken
into account. We perform the numerical analyses of the dependences of the amplitudes of oscillations of fluid in the basin
on the parameters of the atmospheric front and the choice of the formulas for the tangential wind stresses. The influence
of the wind stresses leads to significant quantitative and qualitative changes in the oscillations of fluid in the basin as
compared with the case of pure baric action. 相似文献
3.
V. N. Kudryavtsev 《Physical Oceanography》1996,7(2):99-125
This paper discusses a simplified model for the evolution of the atmospheric planetary boundary layer overlying a thermal
front in the sea. The model provides local values of the friction/heat transfer geostrophic coefficients and the direction
of surface wind stress, as well as the wind/temperature profiles at any point on the front. With the running over a warm front,
the baroclinicity of the internal boundary layer leads to the generation of a near-surface current of air directed down the
front. The model can be used to interpret radar imagery of the sea surface with the purpose of determining its mesoscale variability.
Translated by Vladimir A. Puchkin. 相似文献
4.
We consider a plane problem of generation of surface and internal waves in a bounded rotating basin of variable depth by a
front of atmospheric pressure moving over the basin. The fluid is assumed to be two-layer. The system of nonlinear long-wave
equations is solved numerically by the method of finite differences for the distribution of depths corresponding to a zonal
section of the Black-Sea basin. It is shown that the baric front moving over the basin generates barotropic and baroclinic
oscillations of the fluid. The intensity of disturbances depends on the velocity of motion and the width of the front. There
exists a velocity of motion of the front for which internal waves are generated especially efficiently. When the front leaves
the basin, we observe the formation of a packet of internal waves propagating from one lateral boundary of the basin to the
other boundary with reflections from the boundaries. 相似文献
5.
每年冬季因中国北方冷空气前缘东移出海南下而形成的锋面是造成台湾海峡内恶劣海况的原因之一，锋面的到临常引发快速增高的波浪，这种海况是目前作业化数值预报模式在操作上不易反映的。经验证明根据元素波模式推衍所得的面积风域法推算波浪，适合于推导季风期间海况的一种方法。本文将锋面期间风域是移动的特性结合面积风域理论，作为推算锋面抵达时推算波高的方法。本文提出加权风场内插法计算各时刻各网格点的风速，使得面积风域理论简化为在网格点上的离散计算。文中根据锋面期间实际观测数据计算波能传播速率与风能传播系数等参数，经由案例分析的结果显示这个离散化面积风域法可以合理地推算锋面期间快速成长的波高。 相似文献
6.
Kuniaki Okuda 《Journal of Oceanography》1982,38(1):28-42
The internal flow structure of wind waves in a wind-wave tunnel was investigated on the bases of the measured vorticity distributions, streamline patterns, internal pressure fields, and stress distributions at the water surface for some waves in the field. In part I the experimental method and the internal vorticity structure relative to the individual wave crests are described. The measured vorticity distributions of distinct waves (waves with waveheight comparable with or larger than that of significant wavesH 1/3) in the field indicate that the surface vorticity layer is extraordinarily thickened near the crest, and the vorticity near the water surface shows a particularly large value below the crest. The flow near the crest of distinct waves is found to be in excess of the phase speed in a very thin surface layer, and the tangential stress distribution has a dominant peak near the crest. It is argued that the occurrence of the region of high vorticity in distinct waves is associated with the local generation of vorticity near the crest by tangential stress which attains a peak, under the presence of excess flow. 相似文献
7.
波浪破碎是一个强非线性过程,破碎时产生的大量气泡在海面上表现为白冠,白冠覆盖率是刻画波浪破碎一个重要参数。研究表明,白冠覆盖率与海上风速、海浪状态和大气稳定度等多种海洋环境因素有关。综合前人的观测数据,本文给出了更为可靠的依赖风速的白冠覆盖率公式,发现海水温度越高,白冠覆盖率越大。提出了以波浪破碎耗散函数为参数的白冠覆盖率公式,同时发现波龄小于某个临界值时,白冠覆盖率随波龄增大,波龄大于临界值时,白冠覆盖率保持不变,该临界值随风速增大而减小。 相似文献
8.
S. F. Dotsenko 《Physical Oceanography》1990,1(6):405-410
Resonance excitation of internal waves by running waves of the atmospheric pressure and the tangential wind stress in a continuously stratified rotating ocean is studied in a linear statement. A comparative analysis of the rates of the increase in amplitude of resonance-excited waves for these external disturbances is carried out numerically for the case of the average distribution of the Väisälä-Brunt frequency in the Caribbean Sea.Translated by Mikkail M. Trufanov. 相似文献
9.
The plane problem on the generation of linear internal waves by a moving area of time-harmonic surface pressures in a continuously-stratified ocean of constant depth is considered. An analytical relation has been derived for forced internal waves off the site of their generation in the form of an internal wave field superposition corresponding to individual vertical modes. The possible wave regimes are determined. For the Brunt-Väisälä frequency distribution in the North Atlantic, the generation conditions and amplitudes of diverse radiated waves are numerically determined.Translated by Vladimir A. Puchkin. 相似文献
10.
S. N. Kulichkov N. D. Tsybulskaya I. P. Chunchuzov V. A. Gordin Ph. L. Bykov A. I. Chulichkov V. G. Perepelkin G. A. Bush E. V. Golikova 《Izvestiya Atmospheric and Oceanic Physics》2017,53(4):402-412
Internal gravity wave (IGW) data obtained during the passage of atmospheric fronts over the Moscow region in June–July 2015 is analyzed. IGWs were recorded using a group of four microbarographs (developed at the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences) located at distances of 7 to 54 km between them. Regularities of variations in IGW parameters (spatial coherence, characteristic scales, propagation direction, horizontal propagation velocity, and amplitudes) before, during, and after the passage of an atmospheric front over the observation network, when the observation network finds itself inside the cyclone and outside the front, are studied. The results may be useful in studying the relationships between IGW effects in different physical fields at different atmospheric heights. It is shown that, within periods exceeding 30 min, IGWs are coherent between observation points horizontally spaced at distances of about 60 km (coherence coefficient is 0.6–0.9). It is also shown that there is coherence between wave fluctuations in atmospheric pressure and fluctuations in horizontal wind velocity within the height range 60–200 m. A joint analysis of both atmospheric pressure and horizontal wind fluctuations has revealed the presence of characteristic dominant periods, within which cross coherences between fluctuations in atmospheric pressure and wind velocity have local maxima. These periods are within approximate ranges of 20–29, 37–47, 62–72, and 100–110 min. The corresponding (to these dominant periods) phase propagation velocities of IGWs lie within an interval of 15–25 m/s, and the horizontal wavelengths vary from 52 to 99 km within periods of 35 to 110 min, respectively. 相似文献
11.
I. P. Chunchuzov V. G. Perepelkin S. N. Kulichkov G. I. Gorchakov M. A. Kallistratova A. V. Dzhola J. Lyu P. Teng Y. Yang W. Lin Q. Li Y. Sun 《Izvestiya Atmospheric and Oceanic Physics》2017,53(5):524-538
The influence of internal gravity waves on the spatial coherence and temporal variability of the atmospheric pressure, wind velocity, and gas constituents near Moscow and Beijing is studied in the mesoscale range of periods: from a few tens of seconds to several hours. The results of simultaneous measurements of variations in the atmospheric pressure (using a network of spaced microbarographs), wind velocity at different heights of the atmospheric boundary layer, and gas constituents are given for each city. The wave structures are filtered using a coherence analysis of the atmospheric pressure variations at different measurement sites. The dominant periods and the coherences, phase speeds, and horizontal scales of variations corresponding to these periods are estimated. The general mechanism of the influence of wave structures on meteorological fields and gas constituents is discussed, which is independent of the measurement site and the specificity of meteorological conditions. 相似文献
12.
This study investigates atmospheric responses to the directions of surface wind over the Kuroshio front in the East China Sea, using wintertime satellite-derived data sets. Composite maps of sea surface temperature, wind speed, precipitation, turbulent heat flux, surface wind divergence, and the curl of wind vectors above the atmospheric boundary layer are depicted based on the classification of intense northeasterly (along the front) and northwesterly (across the front) winds over the East China Sea. When northeasterly winds prevail, considerable precipitation occurs on the offshore side of the Kuroshio front, in contrast to periods when northwesterly winds prevail. First, the northeasterly winds strengthen above the front because of the downward transfer of momentum from the fast-moving air at higher levels and/or an adjustment of sea level pressure over the oceanic front, although the process by which the influence of the Kuroshio penetrates beyond the marine atmospheric boundary layer remains unclear. Second, a cyclonic vortex forms above the marine atmospheric boundary layer (at 850-hPa height) on the offshore side of the front, and thereafter, surface wind convergence via Ekman suction (hence, enhanced precipitation) occurs over the East China Sea shelf breaks. The northeasterly winds blow over the East China Sea when the Aleutian Low retreats to the east and when high sea level pressure covers the northern Sea of Japan. 相似文献
13.
A moving low atmospheric pressure is a main feature of tropical cyclones, which can induce a system of forced water waves and is an important factor that cause water level rise during a storm. A numerical model based on the nonlinear shallow water equations is applied to study the forced waves caused by an atmospheric pressure disturbance moving with a constant velocity over water surface. The effects of the moving speed, the spatial scale and the central pressure drop of the pressure disturbance are discussed. The results show that the wave pattern caused by a moving low-pressure is highly related with its moving speed. The wave pattern undergoes a great change as the moving speed approaches the wave velocity in shallow water. When the moving speed is less than the wave velocity, the distribution of water surface elevation is nearly the same as that of the pressure disturbance, and the maximum of the water surface elevation is located at the center of pressure. When the moving speed is larger than the wave velocity, a triangle shaped wave pattern is formed with a depression occurs in front of the pressure center, and the maximum of the water surface elevation lags behind the center of pressure. As the moving speed increases, the maximum of the water surface elevation firstly increases and then decreases, which reaches a peak when the moving speed is close to the wave velocity. The maximum of water surface elevation is approximately in proportion to the central pressure drop, and slightly affected by the spatial scale of pressure disturbance. Both the central pressure drop and the spatial scale of the pressure disturbance do not significantly affect the forced wave pattern. However, a clear difference can be noticed on the ratio of the maximum water surface elevation in moving pressure situation to that in static situation, when the moving speed is close to the wave velocity. A pressure disturbance with smaller spatial scale and smaller central pressure drop will give a larger ratio when the moving speed is close to the wave velocity. 相似文献
14.
The statistical analysis of the long-term data on the variability of the Baltic Sea level has revealed the complicated character of the wave field structure. The wave field formed by the variable winds and the disturbances of the atmospheric pressure in the Baltic Sea is a superposition of standing oscillations with random phases. The cross spectral analysis of the synchronous observation series of the level in the Gulf of Finland has shown that the nodal lines of the standing dilatational waves are clearly traced with frequencies corresponding to the distance from the nodal line to the top of the gulf (a quarter of the wave length). Several areas of the water basin with clearly expressed resonant properties may be distinguished: the Gulfs of Finland, Riga, and Bothnia, Neva Bay, etc. The estimations of the statistical correlation of the sea level oscillations with the variation of the wind and atmospheric pressure indicate the dominant role of the zonal wind component during the formation of the floods in the Gulf of Finland. The probable reason for the extreme floods in St. Petersburg may be the resonance rocking of the eigenmode oscillations corresponding to the basic fundamental seiche mode of the Gulf of Finland with a period of 27 h when the repeated atmospheric disturbances in the Baltic Sea occur with a period of 1–2 days. 相似文献
15.
本文总结和归纳了已有的台风海面风场模式，按照风场模式物理背景的不同进行了分类．在此基础上，本文选择并建立了一种新的台风海面风场动力诊断模式．首先，利用台风影响范围内某条具有代表性的闭合等压线的拟合方程表示出台风海面气压场，并利用改进的气压场模式和修正的梯度风方程求得台风系统风场，同时还利用宫崎正卫的热带气旋合成风假设建立移行台风风场．然后将两者作权重订正后进行迭加，即得到台风模型风场．该模式考虑了包括台风气压场的非对称性、边界层摩擦效用、气压梯度的切向变化及台风中心移动的影响等多种因素．经过对0519号“龙王”台风的模拟，结果表明本文所建立的台风风场模式可以比较准确的模拟出非圆对称的台风海面气压场和海面风场，较为真实地反映实际台风风场的特征． 相似文献
16.
在小风速条件下,分层水中,水下运动物体所产生的内波,通过改变表面流场,使得风浪中的短波波面斜率分布发生了改变。由此,可以通过观察表面风浪中短波波面斜率分布的变化,识别出水下运动物体的移动轨迹 相似文献
17.
Atmospheric frontal gravity waves observed in satellite SAR images of the Bohai Sea and Huanghai Sea 总被引：1，自引：0，他引：1
LIU Shuming LI Ziwei YANG Xiaofeng Pichel William G YU Yang ZHENG Quanan LI Xiaofeng 《海洋学报(英文版)》2010,29(5):35-43
In the satellite synthetic aperture radar (SAR) images of the Bohai Sea and Huanghai Sea, the authors observe sea surface imprints of wave-like patterns with an average wavelength of 3.8 km. Comparing SAR observations with sea surface wind fields and surface weather maps, the authors find that the occurrence of the wave-like phenomena is associated with the passing of atmospheric front. The authors define the waves as atmospheric frontal gravity waves. The dynamical parameters of the wave packets are derived from statistics of 9 satellite SAR images obtained from 2002 to 2008. A two-dimensional linear physical wave model is used to analyze the generation mechanism of the waves. The atmospheric frontal wave induced wind variation across the frontal wave packet is compared with wind retrievals from the SAR images. The CMOD-5 (C-band scatterometer ocean geophysical model function) is used for SAR wind retrievals VV (transmitted vertical and received vertical) for ENVISAT and HH (transmitted horizontally and received horizontally) for RADARSAT-1. A reasonable agreement between the analytical solution and the SAR observation is reached. This new SAR frontal wave observation adds to the school of SAR observations of sea surface imprints of AGWs including island lee waves, coastal lee waves, and upstream Atmospheric Gravity Waves (AGW). 相似文献
18.
On transformation of the near-surface atmospheric boundary layer in the ocean temperature front area
A two-dimensional, quasi-analytical model for the formation of the internal atmospheric boundary layer in the ocean temperature front area is described, developed on the basis of integral relations for motion and thermal conductivity equations. The computed data are matched with wind speed observations, as well as with direct and indirect dynamic velocity measurements in the air, obtained across the Gulf Stream frontal zone.Translated by V. Puchkin. 相似文献
19.
We consider a plane problem of barotropic seiches generated by a front of atmospheric pressure moving over a bounded basin.
A system of nonlinear equations of long waves is solved by the finite-difference method with regard for the bottom friction
and Earth's rotation. The numerical analyses are performed for two basins with distributions of depths typical of the Black
Sea. It is shown that the passage of a baric front over the basin leads to the generation of lower seiches. The oscillations
of level and the corresponding currents are especially intense in the shallow-water zones of the basins. The seiches become
more intense as the velocity of transfer of the atmospheric front increases and the width of the front decreases. Earth's
rotation leads to the generation of longshore currents and promotes the process of weakening of residual oscillations of the
fluid following the passage of the front. The influence of nonlinearity on seiches is small for the analyzed basins.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 3–18, March–April, 2008. 相似文献
20.
获取高分辨率的风场数据和气压场数据是精确模拟台风浪的基础,采用经验公式构建台风风场和气压场对海浪模式进行驱动,无法反映台风影响下海气动力过程,难以提供高精度的风场、气压场数据。本文基于中尺度大气模式WRF(Weather Research and Forecasting model)和第三代海浪模式SWAN(Simulating WAves Nearshore model),构建了南中国海地区大气—海浪实时双向耦合模式,针对超强台风"威马逊"进行数值模拟。将数值模拟结果与现场观测结果及卫星高度计观测结果进行对比验证,验证结果表明,本文建立的WRF-SWAN耦合模式在对台风"威马逊"影响下的南中国海台风浪的模拟中展现出较高的模拟精度,揭示了台风风场分布和台风浪分布在空间上的"右偏性"不对称分布特征及其形成机制。基于WRF和SWAN建立的大气-海浪实时双向耦合模式能够准确模拟台风动力过程以及台风浪的时空分布特征,可以推广用于南中国海地区台风浪的模拟分析。 相似文献