共查询到20条相似文献，搜索用时 31 毫秒
1.
S. A. Grodsky V. N. Kudryavtsev A. N. Bol'shakov V. E. Smolov 《Physical Oceanography》2001,11(4):333-352
On the oceanographic platform of the Marine Hydrophysical Institute of the Ukrainian National Academy of Sciences, we performedin situ investigations of surface waves based on the analysis of the fluctuations of radar signals at a wavelength of 1.2 cm. We
analyzed both the traditional modulation transfer function used to describe variations of the scattering cross section for
the scales of surface waves and the correlation of mean variations of the level of radar signals with the group structure
of waving. This is of interest for applications in medium-resolution radar systems (−200–500m) recording the group structure
of waving in the process of its smoothing. The experimental estimations of the amplitude of variations of radar signals caused
by the group structure of waving are in good agreement with numerical results obtained with the help of a two-scale model
of scattering of radar signals by the sea surface.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
2.
We study the problem of subsatellite calibration of a side-looking radar (SLR) of the Sich-1M satellite regarded as an instrument for the evaluation of the velocity of surface wind and discuss the possibility of application
of the meteorological and wave parameters measured from the stationary oceanographic platform of the Experimental Department
of the Marine Hydrophysical Institute (Ukrainian Academy of Sciences) for their evaluation in the remote regions of the sea.
These regions can be observed with the help of the SLR without errors introduced by the appearance of the coast in elements
of space resolution. To prove the indicated possibility experimentally, we perform simultaneous measurements of the water
and air temperatures, wind velocity, and the characteristics of waves both from the platform and in the water area neighboring
with the platform on the side of the sea at distances of up to 4.8 km. The quantitative estimates of the degree of space uniformity
of the analyzed parameters are deduced under the conditions of stable inshore wind. A conclusion is made that the platform
can be used for subsatellite measurements aimed at the validation and improvement of the algorithm of reconstruction of the
velocity of surface wind by using the SLR of the Sich-1M satellite.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 31–43, May–June, 2005. 相似文献
3.
V. I. Babii 《Physical Oceanography》2001,11(3):291-298
We consider specific errors of measuring the velocity of sound in water caused by the effect of heating of the analyzed volume
of the medium by acoustic irradiation and the influence of the velocity of the incident flow. We deduce expressions for the
optimal values of the intensity of sounding acoustic radiation and the velocity of the incident flow guaranteeing the minimum
possible value of the resulting error and give recommendations concerning thein situ measurements of the sound velocity.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
4.
On the basis of the analysis of the data of hydrological observations, we construct an empirical dependence of the vertical
heat fluxQ on the temperature gradientT
z
. The integral advective-diffusive transfer is taken into account by the method of Kolesnikov. We obtain a generalized dependence
of the coefficient of vertical thermal diffusivityK
z
onT
z
and note that the well-known Rossby-Montgomery relation and Kolesnikov formula are its special cases. We analyze the possibility
of application of this dependence to linear and nonlinear problems of thermal conductivity and diffusion in the ocean.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
5.
Yu. G. Yurovsky 《Physical Oceanography》2000,10(3):283-286
For the submarine springs of underground water located in the karst cavities of Cape Aiya, we suggest a solution based on
the modification of the model of flow rate of water and application of the formulas of mixing. We also give methodical recommendations
helpful for the reliable determination of empirical parameters under thein situ conditions.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
6.
On the basis of the satellite and ship data of many-year observations, we parametrize the albedo of the ocean-atmosphere system
both for the conditions of “fair weather” and for the maximum and climatic optical thicknesses of oceanic clouds. These results
are used to develop a procedure of practically exact reconstruction of the monthly average fluxes of integral solar radiation
and the radiation budget over the ice-free surface of the oceans according to the data of satellite measurements of albedo
(Nimbus NOAA satellite, 1974–1983) for arbitrary conditions of transparency of the atmosphere and cloudiness. We determine the current
and climatic monthly average values and the characteristics of interannual variability of all components of the radiation
mode of the ocean-atmosphere system with a spatial resolution of 500×500 km.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
7.
全极化SAR图像中溢油极化特征研究 总被引：2，自引：1，他引：1
相比于单极化SAR图像,全极化SAR图像不仅能体现海面目标的几何特征、后向散射特征,还能体现目标的极化特征。因此,在溢油检测方面,极化SAR更具优势。特征提取作为溢油检测的关键步骤,直接影响到溢油检测的精度。在本文中,我们分析了全极化SAR图像中海面溢油的极化特征,如极化散射熵、平均散射角等。并提出了新的极化特征P,该特征参数能够反映海面目标电磁散射过程中布拉格散射机制和镜面散射机制的比例。为了研究极化特征溢油检测的能力,本文基于SIR-C/X-SAR和Radarsat-2全极化SAR图像开展了相关实验,并对比分析了溢油的多种极化特征。实验结果显示,在中低风速情况下,C波段溢油探测效果优于L波段;本文提出的极化特征P对海面散射机制敏感;基准高度和特征参数P在C波段比其他极化特征更适于溢油检测。 相似文献
8.
With the help of a combined model of wind and waves, we study the influence of films of surfactants on the spectrum of short
wind waves and the parameters of the lowest layer of the atmosphere. It is shown that the films of surfactants decrease the
roughness of the sea surface as a result of suppression of short wind waves, which decreases the coefficient of resistance
of the sea surface and the coefficient of turbulent heat exchange. The maximum influence of films on the exchange coefficients
is attained forU∼10 m/s. In this case, the relative decrements of the coefficients of resistance and turbulent heat exchange are equal to
15 and 9%, respectively.
Translated by Peter V. Malyshev and Dmitry V. Malyshev UDC 551.46 相似文献
9.
N. P. Bulgakov S. N. Bulgakov V. N. Davydova A. Z. Martinez 《Physical Oceanography》2000,10(3):233-243
On the basis of the data of thein situ measurements of current velocities and other basic hydrophysical parameters (temperature and salinity) performed in the course
of Cruise 41 of the R/VAkademik Vernadsky, we analyze the variability and stability of the North Brazil Current in winter. We also study the possibility of the influence
of the baroclinic component of the horizontal drop of hydrostatic pressure on the vertical profile of the current velocity
and estimate the intensity of the transport of waters.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
10.
在对南海石油平台所处的南海北部海域海底地形、平均海平面、风浪时空分布等进行分析基础上,利用南海石油平台水位计对Jason-2卫星高度计进行了测高绝对定标,定标结果为30.9 cm±7.8 cm,分析发现南海北部中尺度涡可能对定标结果产生影响;利用南海石油平台测波雷达对Jason-1高度计有效波高进行了精度检验,Jason-1高度计Ku波段和C波段有效波高测量的均方根误差分别为0.43 m和0.45 m。分析和检验结果表明,南海石油平台所处海洋环境条件、平台上装载的水位计和测波雷达均满足卫星雷达高度计定标与检验要求。南海石油平台定标场预期可用于中国海洋二号卫星和其他卫星高度计的定标与检验。 相似文献
11.
We perform the numerical analysis of the long-wave response of the free surface of a fluid in a basin of variable depth to
the formation of an anomaly of the baric field for a finite period of time. In numerical experiments, we use the distribution
of depths typical of the south coast of the Crimea. We also study the dependence of the dynamics of the sea level in the zone
of the baric anomaly and in the shelf zone on the space and time scales of local changes in the field of atmospheric pressure
in the open part of the basin.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
12.
V. V. Malinovsky 《Physical Oceanography》1992,3(6):443-454
The results of investigations of the statistical characteristics of spikes of radar signals scattered by the sea surface at grazing angles and borizontally polarized radiation are reported. The measurements were conducted at wind speeds ranging from 2.8 to 9 m s–1 and at various azimuthal directions relative to the general sense of wind wave propagation. The relationship between the theoretically and experimentally derived distribution parameters allows a conclusion about the linear dependence of spike amplitudes on the extent of instable areas. The theoretical model provides a qualitatively authentic azimuthal nature of the variation of the mean radar signal.Translated by V. Puchkin. 相似文献
13.
S. I. Kondratev V. V. Dolotov Yu. G. Moiseev Yu. T. Shchetinin 《Physical Oceanography》2000,10(3):257-272
We performed a search for local coastal submarine springs of fresh water in the region from Cape Feolent to Cape Sarych (down
to an isobath of 40m). Stable submarine springs of brackish water with the minimum salinity of 5.5‰ and the minimum total
output of 30,000 m3/day were discovered only near the west wall of Cape Aiya. It is shown that brackish waters discharging from these springs
spread over the sea surface in the form of a thin layer (up to 1 m in thickness) characterized by lower salinity, higher transparency,
and an elevated content of silicic acid. We make a conjecture that the appearance of 2–3-m-thick layers of water with higher
transparency and lower salinity at depths of 5–8 m is explained by the discharge of unknown bottom springs of underground
fresh water.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
14.
A. M. Chukharev 《Physical Oceanography》1999,10(2):175-182
For a one type of temperature turbulent convection observed in the ocean, i.e., for the two-dimensional roller-type convection,
we propose a model intended for the evaluation of the intensity and depth of penetration of convective motions as functions
of a given heat flow from the sea surface and the temperature gradient in the thermocline. This model is based on the methods
of the theory of turbulent jets and experimental data on the vertical distribution of temperature in the course of convection.
The comparison of the calculated dimensionless values of the depth of penetration of the thermocline in autumn and winter
shows a good qualitative agreement with the data ofin situ measurements.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
15.
海洋微波散射模型相比于以经验统计建立的地球物理模式函数具有不受特定微波频率限制的优势。组合布拉格散射模型和几何光学模型形成了复合雷达后向散射模型。利用南海北部气象浮标2014年海面风速风向实测值作为散射模型输入，分别比较了复合雷达后向散射模型与RADARSAT-2卫星C波段SAR、HY-2A卫星Ku波段微波散射计的海面后向散射系数，偏差分别为(?0.22±1.88) dB (SAR)、(0.33±2.71) dB (散射计VV极化）和(?1.35±2.88) dB (散射计HH极化)；以美国浮标数据中心(NDBC)浮标2011年10月1日至2014年9月30日共3年的海面风速、风向实测值作为散射模型输入，分别比较了复合雷达后向散射模型与Jason-2、HY-2A卫星Ku波段高度计海面后向散射系数，偏差分别为(1.01±1.15) dB和(1.12±1.29) dB。中等入射角和垂直入射下的卫星传感器后向散射系数观测值与复合雷达后向散射模型模拟值比较，具有不同的偏差，但具有相同的海面风速检验精度，均方根误差小于1.71 m/s。结果表明，复合雷达后向散射模型可模拟计算星载SAR、散射计和高度计观测条件下的海面雷达后向散射系数，且与CMOD5、NSCAT-2、高度计业务化海面风速反演的地球物理模式函数的计算结果具有一致性；复合雷达后向散射模型可用于微波遥感器的定标与检验、海面雷达后向散射的模拟。 相似文献
16.
Abstract Geoid heights and vertical deflections derived from satellite radar altimetry contain characteristic signals that may be reproduced and explained by simple models for seamount gravitation acting on the sea surface. Computer algorithms capable of automatic operation and able to detect, approximately locate, and estimate parameters constraining the shape of actual sea‐mounts were written and tested. The computer program which utilized a digital high‐pass filter combined with a roughness sensor was effective in separating the seamount produced geoid undulation/vertical deflection pattern from the remaining data track features, simultaneously detecting and locating along the track such signals. Tests of the algorithm on several SEASAT passes over known bathymetry produced mixed results. Meaningful shape constraints were obtained by matching the geoid anomaly calculated from the seamount model to the actual mean sea level pattern for some seamounts. Results for other seamounts were poor and possible reasons for the failure are discussed. It is concluded that a computerized seamount detection program for radar altimetry data is feasible, but it will have to be more complex than the present one for fully successful operation. 相似文献
17.
S. V. Motyzhev 《Physical Oceanography》2000,10(6):561-568
We present the results of drift experiments with 14LOBAN-TM buoys carried out for the first time in the Black Sea in 1987–1997. We analyze the specific features of application of buoys
in summer and winter. We present the main results of investigation of the Main Black Sea Current by drift methods and joint
processing of drift contact and remote infrared observations. We demonstrate the possibility of enhancement of the quality
of observations due to the application of SVPB drifters of new generation equipped with underwater sails and meters of atmospheric
pressure in the near-surface atmospheric layer.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
18.
We analyze the dependence of climatic variations of the location of the upper boundary of the hydrogen-sulphide zone in the
Black Sea on the variations of the sea level and various types of atmospheric circulation (according to A.A. Girs). It is
discovered that the level of correlation between the indicated parameters is high and that the corresponding plots are in
good qualitative agreement. The accumulated results enable us to make an assumption that there exists an 80–100-yr cycle of
variation of all analyzed parameters and that the long-term variations of the location of the upper boundary of the hydrogen-sulphide
zone can be regarded as a manifestation of global climatic variations.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
19.
A. S. Boguslavsky 《Physical Oceanography》1999,10(1):93-97
We solve a nonlinear problem of diffusion from a concentrated source in a moving medium with diffusion coefficient depending
on the scale of the phenomenon, time, and the concentration of impurities. We obtain a family of exact solutions of this problem,
which can be regarded as a generalization of the class of linear problems of diffusion considered earlier for the conditions
of the ocean and atmosphere by Roberts, Ozmidov, Obukhov,et al.
Translated by Peter V. Malyshev and Dmitry V. Malyshev. 相似文献
20.
基于二维激光观测的溢油及其乳化过程散射模式研究进展 总被引：2，自引：1，他引：1
合成孔径雷达(SAR)以其高分辨率、能不受雨云影响实施全天时全天候全方位监测,在海面溢油灾害应急监测过程中发挥着越来越重要的作用。溢油是因为海面油膜抑制了毛细波和重力波,在SAR图像上呈暗斑而被识别。然而,海面溢油的乳化过程直接影响SAR对海面溢油后向散射截面的观测精度。本研究以物理海洋学和激光原理以及海面电磁散射理论为基础,通过实验利用激光扫描仪观测海面溢油粗糙度,分别与溢油特征参数、后向散射系数建立对应关系;耦合海面溢油参数与后向散射截面的关系,利用电磁散射数值建模方法,建立海面溢油散射模型,研究海面溢油乳化过程对微波后向散射截面的影响。本项目的研究将为SAR监测海面溢油量、溢油厚度及油品分布格局提供了可能;将进一步揭示海面溢油的散射机制,提高SAR海面监测溢油的精度和能力。 相似文献