共查询到20条相似文献，搜索用时 187 毫秒
1.
The peculiarities of seasonal variability of the calculated sound speed and elements of its vertical stratification in the
northern Black Sea continental slope are considered. Typical acoustic structures have been identified. The impact of seasonal
variability of the sound speed upon the ray characteristics of acoustic fields is studied.
Translated by Vladimir A. Puchkin. 相似文献
2.
N. P. Bulgakov R. A. Yaroshenya E. A. Skripaleva L. A. Voskresenskaya 《Physical Oceanography》2000,10(4):331-350
Climatic frontal zones are selected in the thermohaline fields of the Tropical Atlantic by analyzing the many-year-average
seasonal database reduced to the nodes of a one-degree grid. We determine physical characteristics of the frontal zones, study
their spatial and temporal variability, and reveal basic regularities of the appearance of frontal zones in the fields of
thermohaline characteristics.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
3.
G. K. Korotaev A. S. Sarkisyan V. V. Knysh P. N. Lishaev 《Izvestiya Atmospheric and Oceanic Physics》2016,52(4):418-430
A retrospective analysis has been done for the hydrophysical fields of the Black Sea for 1993–2012 with the assimilation of undisturbed monthly average profiles of temperature and salinity that were obtained by using an original procedure of joint processing of satellite altimetry and rare hydrological observations. The accuracy of the reconstructed fields of temperature and salinity of the Black Sea is evaluated by comparison with the data of sounding from the hydrological stations and the Argo floats. A comparative analysis is performed for the integral characteristics of the fields of temperature, salinity, and kinetic energy with the same characteristics of the reanalysis for 1992–2012 that assimilated the average annual profiles of temperature and salinity, surface temperature and altimetry level of the sea after being adjusted with respect to climate seasonal variability. The proposed procedure of the reanalysis execution allows a more precise reconstruction of the interannual variability of temperature and salinity stratification in the main pycnocline. The correlation between the annual and seasonal variability of the eddy of the wind friction tangential stress and the average kinetic energy at the levels is revealed. 相似文献
4.
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.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 3–17, July–August, 2006. 相似文献
5.
We analyze the seasonal variability of the climatic hydrophysical fields of the Black Sea reporduced in three numerical experiments
carried out according to the model of circulation. The numerical predictions are performed for a period of 12.5 yr on the
basis of the hydrological data accumulated in 1983–1995. The monthly average climatic fields of the current speed are reconstructed
according to the data on the climatic fields of temperature and salinity by the method of hydrodynamic adaptation (standard).
It is shown that, in prognostic calculations, the seasonal variability of temperature and salinity is qualitatively close
to the “standard” dependence. At the same time, the quantitative difference between the climatic behavior of the model and
the standard dependence may be significant. The annual cycle of the currents is characterized by the intensification of the
Main Black-Sea Current in winter. The structure of the hydrophysical fields of the sea in the model becomes much more realistic
if it is based on the actual hydrological data.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
6.
The hydrographic fields in the Arctic region are calculated with a three-dimensional nonlinear model of the general circulation
in the World Ocean using climatic databases on temperature, salinity, and wind stress. The calculation results show that the
seasonal variability of the fields is negligible. The salinity distribution almost does not change from season to season,
and slight temperature differences are found only in the upper layer. In the winter period, a moderate intensification of
the currents is observed. The formation of an intermediate low-salinity layer is revealed at the Subantarctic front, where
the intensive turbulence and transverse circulation in the Antarctic Circumpolar Current near the front result in the sinking
of the surface low-salinity waters down to intermediate depths. The low-salinity water propagates in the oceans at intermediate
depths northward from the front by advection. The integral values of the seasonal transport of mass, heat, and salt in various
sections are presented in tables, and the distributions of appropriate characteristics in these sections are shown in figures.
According to the calculations, the highest seasonal variations of heat, salt, and mass exchange in the Antarctic region and
adjacent oceans are found in the Atlantic sector. 相似文献
7.
For the Black-Sea region, we perform the dynamic reanalysis of the data on atmospheric circulation for the period 1958–2001
by using the HadRM3P model with a space resolution of 25 km. We estimate the mean climatic atmospheric fields of vorticity and divergence of the
wind velocity and study their space structure and seasonal variability. The climatic estimates of the annual course of vorticity
of the wind velocity over the sea are presented. The obtained large annual average values of vorticity of the velocity reveal
the predominant role played by the wind action in the generation not only of the seasonal variability but also of the mean
cyclonic circulation of waters in the Black Sea. 相似文献
8.
As the spatio-temporal variability of the Kuroshio is highly influenced by mesoscale eddies, representing its seasonal variability characteristics requires sufficiently long term observations to reduce... 相似文献
9.
The formation of the fields of surface winds over the Black Sea occurs under the action of numerous physical factors. One
of the most important factors is the monsoon mechanism connected with the seasonal variations of buoyancy contrasts over the
sea and surrounding land. To separate the effects caused by this mechanism, we performed and described the numerical experiments
aimed at the evaluation of the sensitivity of the regional model of atmospheric circulation to the variations of land–sea
temperature contrasts. It is shown that the influence of these effects is restricted to the lower part of the atmosphere.
The presented estimates of the climatic fields of disturbances enable us to describe the monsoon mechanism specifying the
seasonal variability of the field of vorticity of the wind velocities and, as a consequence, the seasonal variability of the
large-scale circulation of waters in the Black Sea. 相似文献
10.
Ivanov V. A. Lyubartseva S. P. Mikhailova É. N. Shapiro N. B. Shteinman B. S. 《Physical Oceanography》2002,12(2):65-87
We discuss the results of a numerical experiment devoted to the investigation of the variability of the three-dimensional fields of temperature and current velocity brought about by the seasonal variability of external factors: solar radiation, atmospheric fields, discharge of the river Jordan, and water intake for economic necessities. We use a multilayer model in isopycnic coordinates with an upper mixed layer. We set atmospheric factors in the form of monthly average fields that are uniform over space and linearly interpolated in time. We compare the computed fields of heat flux and evaporation through the lake surface, level, temperature, and currents with data of observations. We note a qualitative agreement of temperature fields during the whole year and current velocities in winter when the lake is, in fact, barotropic. In summer when the lake is stratified, currents in the model turn out to be weaker than in observations. 相似文献
11.
N. P. Bulgakov R. A. Yaroshenya E. A. Skripaleva L. A. Voskresenskaya 《Physical Oceanography》2000,11(1):65-78
On the basis of the many-year-average seasonal data array of temperature and salinity presented on a scale of one-degree averaging,
by using a special quantitative criterion, we reveal a climatic frontal zone and determine both its physical and hydrological
characteristics (such as the length width, and thickness of the frontal layer and the temperature, salinity, and density gradients)
and its geographic coordinates. The many-year average seasonal variability of these characteristics is analyzed.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
12.
A reanalysis of atmospheric circulation in the Black Sea region is performed with a high spatial resolution of 25 × 25 km for the period from 1958 to 2001. Climatic wind speed fields are estimated, as are their spatial structure and seasonal variability. Mesoscale regions of cyclonic and anticyclonic speed vorticity, which are connected with edge effects and orography, are distinguished. To single out the monsoon mechanism in the annual votricity cycle, numerical experiments on the sensitivity that the regional atmospheric circulation has to the sea-surface temperature perturbations have been carried out. Large-scale regional peculiarities of the surface wind field are considered for different seasons. The vorticity of the surface wind speed and strength is assessed. Large annual average values of the vorticity are obtained which are comparable with the range of seasonal variability; they evidence the defining role that wind plays in the generation and seasonal variability, as well as the average cyclonic water circulation in the Black Sea. 相似文献
13.
F. Pogarskii V. Polnikov S. A. Sannasiraj 《Izvestiya Atmospheric and Oceanic Physics》2012,48(6):639-656
In this paper, a detailed statistical analysis of the wind and wave fields in the Indian Ocean (IO) for the period of 1998-2009 was performed based on using the wind fields taken from the site of the National Centers for Environmental Prediction and the National Oceanic and Atmospheric Administration (NCEP/NOAA) [1] and on the numerical wind-wave model WAM [2] modified with the source function proposed in [3]. The primary analysis of the fields includes mapping the wind and wave fields, as well as their energy fields, calculated with different scales of space-time averaging; the subsequent zoning of the IO area; and assessing the seasonal interannual variability of all the fields and their 12-years trends. Further analysis is carried out taking into account the zoning. This analysis includes a construction of the time series obtained with different scales of space-time averaging for all the fields, a spectral analysis of these series, finding and analyzing the spatial and temporal distribution of extrema of the wind and wave fields (accounting for the their sharing in the zones), and making histograms of the wind and wave fields and calculating their first four statistical moments (in the zones and in the ocean as a whole). The results allow us to evaluate a large set of statistical characteristics of the wind and wave fields in the IO area, scales of their variability, their long-term trends, and the features of distribution for these statistical characteristics in the ocean area as well. 相似文献
14.
The seasonal variability of tropical cyclones (CTCs) generated over the South China Sea (SCS) from 1948 to 2003 is analyzed. It peaks in occurrence in August and few generate in late winter (from January to March). The seasonal activity is attributed to the variability of atmosphere and ocean environments associated with the monsoon system. It is found that the monsoonal characteristics of the SCS basically determine the region of tropical cyclone (TC) genesis in each month. 相似文献
15.
This paper discusses the results obtained through numerical modelling of the annual course of circulation and thermohaline field evolution in the tropical Atlantic under the impact of real wind forcing (from March 1982 to March 1983) and compares them with the calculation of seasonal variability induced by the climatic wind. Changes in the pattern of the equatorial currents and related temperature fields induced by the specific peculiarities in the wind field are analysed.Translated by Vladimir A. Puchkin. 相似文献
16.
The El Niño/Southern Oscillation (ENSO) constitutes a major source of potential predictability in the tropics. The majority of past seasonal prediction studies have concentrated on precipitation anomalies at the seasonal mean timescale. However, fields such as agriculture and water resource management require higher time frequency forecasts of precipitation variability. Regional climate models (RCMs), with their increased resolution, may offer one means of improving general circulation model forecasts of higher time frequency precipitation variability.
Part I of this study evaluated the ability of the Rossby Centre regional atmospheric model (RCA), forced by analysed boundary conditions, to simulate seasonal mean precipitation anomalies over the tropical Americas associated with ENSO variability. In this paper the same integrations are analysed, with the focus now on precipitation anomalies at subseasonal (pentad) timescales.
RCA simulates the climatological annual cycle of pentad-mean precipitation intensity quite accurately. The timing of the rainy season (onset, demise and length) is well simulated, with biases generally of less than 2 weeks. Changes in the timing and duration of the rainy season, associated with ENSO forcing, are also well captured. Finally, pentad-mean rainfall intensity distributions are simulated quite accurately, as are shifts in these distributions associated with ENSO forcing. 相似文献
Part I of this study evaluated the ability of the Rossby Centre regional atmospheric model (RCA), forced by analysed boundary conditions, to simulate seasonal mean precipitation anomalies over the tropical Americas associated with ENSO variability. In this paper the same integrations are analysed, with the focus now on precipitation anomalies at subseasonal (pentad) timescales.
RCA simulates the climatological annual cycle of pentad-mean precipitation intensity quite accurately. The timing of the rainy season (onset, demise and length) is well simulated, with biases generally of less than 2 weeks. Changes in the timing and duration of the rainy season, associated with ENSO forcing, are also well captured. Finally, pentad-mean rainfall intensity distributions are simulated quite accurately, as are shifts in these distributions associated with ENSO forcing. 相似文献
17.
On the basis of the results of calculation and analysis of the characteristics of space variability of the geostrophic component of large-scale zonal currents in the tropical zone of the South Atlantic, its intrayear oscillations, and the components of tangential wind stresses, we establish the regularities of seasonal variability of the system of gradient currents on the ocean surface depending on wind conditions. We describe the specific features of seasonal meridional fluctuations of the midstreams of the geostrophic component of zonal large-scale currents and the intrayear variations of their velocity. 相似文献
18.
19.
This paper discusses the results of a numerical experiment on modelling the seasonal variability of the water circulation
and temperature/salinity fields in the Black Sea. A multi-layered quasi-isopycnic model is used based on primitive equations
and incorporating the upper mixed layer (UML). It is shown that during springtime warming, relatively cold layers emerge in
some areas, due to subduction, from the UML, which then spread virtually over the entire basin and persist until they become
absorbed by the rapidly deepening UML during the period of cooling in winter.
Translated by Vladimir A. Puchkin. 相似文献
20.
The results of shipboard and satellite observations of the synoptic variability in the region of the continental slope south of the Tarkhankut Cape are considered. Ship observations revealed a two-layer circulation system of currents. An anticyclonic meander is localized within the upper mixed layer. A cyclonic disturbance, related to the main Black Sea current, occupies the water column below the seasonal thermocline. The interaction between the thermohaline fields is presumably induced by the anticyclonic atmospheric circulation. The satellite-derived images revealed a complex pattern of the large-scale dynamics of seawater over the entire north-western Black Sea.Translated by Mikhail M. Trufanov. 相似文献