共查询到20条相似文献，搜索用时 31 毫秒
1.
A spatial-temporal analysis of the density field in the large-scale hydrological observation areas in the Tropical Atlantic is carried out. The spectral maximum corresponding to the first baroclinic mode of the planetary Rossby wave is discriminated and studied. It is shown that the seasonal transformation of the large-scale circulation of the current field is connected with the propagation of this wave. A simple quasi-geostrophic model is suggested which describes the seasonal variability of the North Equatorial Countercurrent. The results obtained by this model are compared with the hydrological survey data.Translated by Mikhail M. Trufanov. 相似文献
2.
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
3.
Reconstruction of hydrological fields and reproduction of climatic circulation of World Ocean waters
A. S. Sarkisyan K. V. Ushakov V. S. Arkhipkin A. R. Gorbushkin 《Izvestiya Atmospheric and Oceanic Physics》2016,52(5):524-534
Due to a lack of observational data, the hydrological fields of temperature, salinity, and density used by oceanographers at present remain significantly smoothed. Specifically, this refers to the WOA data distributed freely by the group of Sidney Levitus. This study describes the history of synthesis of hydrological data and mathematical modeling with high resolution. Our aim is to minimize the drawbacks of original data of hydrological fields, improve them with the help of a mathematical model, and thus reproduce the current fields. The results of some realistic calculations are presented. 相似文献
4.
Reanalysis data obtained from data assimilation are increasingly used for diagnostic studies of the general circulation of the atmosphere, for the validation of modelling experiments and for estimating energy and water fluxes between the Earth surface and the atmosphere. Because fluxes are not specifically observed, but determined by the data assimilation system, they are not only influenced by the utilized observations but also by model physics and dynamics and by the assimilation method. In order to better understand the relative importance of humidity observations for the determination of the hydrological cycle, in this paper we describe an assimilation experiment using the ERA40 reanalysis system where all humidity data have been excluded from the observational data base. The surprising result is that the model, driven by the time evolution of wind, temperature and surface pressure, is able to almost completely reconstitute the large-scale hydrological cycle of the control assimilation without the use of any humidity data. In addition, analysis of the individual weather systems in the extratropics and tropics using an objective feature tracking analysis indicates that the humidity data have very little impact on these systems. We include a discussion of these results and possible consequences for the way moisture information is assimilated, as well as the potential consequences for the design of observing systems for climate monitoring. It is further suggested, with support from a simple assimilation study with another model, that model physics and dynamics play a decisive role for the hydrological cycle, stressing the need to better understand these aspects of model parametrization. 相似文献
5.
YOU Lixin MIAO Difan
Engineer No. Harbour Engineering Investigation Design Institute of the Ministry of Communications of China Wuhan P. R. China 《中国海洋工程》1999,(4)
To determine the optimal length of the cross-bay bridge at the Tieshan Port and the impact ofthe bridge on the hydrological environment,a 2-D numerical model is adopted to calculate the variation oftidal level,tidal current field and tidal discharge caused by different lengths of the bridge. 相似文献
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The Chukchi and Beaufort Seas include several important hydrological features： inflow of the Pacific water, Alaska coast current （ ACC ）, the seasonal to perennial sea ice cover, and landfast ice ＇along the Alaskan coast. The dynamics of this coupled ice-ocean system is important for both regional scale oceanography and large-scale global climate change research. A mumber of moorings were deployed in the area by JAMSTEC since 1992, and the data revealed highly variable characteristics of the hydrological environment. A regional high-resolution coupled ice-ocean model of the Chukchi and Beaufort Seas was established to simulate the ice-ocean environment and unique seasonal landfast ice in the coastal Beaufort Sea. The model results reproduced the Beaufort gyre and the ACC. The depthaveraged annual mean ocean currents along the Beaufort Sea coast and shelf hreak compared well with data from four moored ADCPs, but the simulated velocity had smaller standard deviations, which indicate small-scale eddies were frequent in the region. The model resuits captured the sea,real variations of sea ice area as compared with remote sensing data, and the simulated sea ice velocity showed an ahnost stationary area along the Beaufort Sea coast that was similar to the observed landfast ice extent. It is the combined effects of the weak oceanic current near the coast, a prevailing wind with an onshore component, the opposite direction of the ocean current, and the blocking hy the coastline that make the Beaufort Sea coastal areas prone to the formation of landfast ice. 相似文献
9.
Yu. V. Artamonov A. E. Bukatov N. M. Solovei E. A. Skripaleva 《Physical Oceanography》2005,15(4):203-210
By using the linear theory of internal waves in a continuously stratified ideal incompressible liquid of finite depth and
hydrological data, we study the dispersion properties and space structure of the vertical velocity of the first mode of free
internal waves in the Atlantic Ocean. The dependence of the characteristics of waves on the hydrological structure of waters
is analyzed.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 3–10, July–August, 2005. 相似文献
10.
Izvestiya, Atmospheric and Oceanic Physics - The problem of the harmonic internal gravity waves generation in the ocean with real and model hydrological characteristics is solved. For real and... 相似文献
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The method of mathematical model self-organization is applied to handle observations of the hydrological, chemical and biological
parameters of the Sea of Azov, conducted from 1926 through to 1985, in order to identify model equations of the latter's ecosystem.
A set of 43 evolutionary equations have been employed to generate a picture of the ecosystem parameters' continuous variability
and to identify relationships between them. Model calculations of the total catch of freshwater fishes, primary productivity,
zoobenthos, phytoplankton, and other characteristics have demonstrated their being in good agreement with the observations
conducted from 1950 to 1985. A prediction of the ecosystem parameters' evolution for the period from 1985 to 1995 has been
made.
Translated by Vladimir A. Puchkin. 相似文献
13.
The structure and dynamics of the water are studied on the basis of hydrological and meteorological long-term data combined with the materials of field observations over a period longer than half a century in the region of the Ryukyu archipelago. New data about the hydrological characteristics of the waters were obtained. Characteristic differences of waters of various modifications in the main straits between the islands are demonstrated. The dependence of the water structure formation in the straits on the seasonal variability of the water exchange through the straits is distinguished. 相似文献
14.
The long-term evolution of the Black Sea dynamics (1980–2020) is reconstructed by numerical simulation. The model of the Black Sea circulation has 4.8 km horizontal spatial resolution and 40 levels in z-coordinates. The mixing processes in the upper layer are parameterized by Mellor-Yamada turbulent model. For the sea surface boundary conditions, atmospheric forcing functions were used, provided for the Black Sea region by the Euro mediterranean Center on Climate Change (CMCC) from the COSMO-CLM regional climate model. These data have a spatial resolution of 14 km and a daily temporal resolution. To evaluate the quality of the hydrodynamic fields derived from the simulation, they were compared with in-situ hydrological measurements and similar results from physical reanalysis of the Black Sea. 相似文献
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The longitude of the western limit of the equatorial Pacific upwelling is a key parameter for studies of carbon budget and pelagic fisheries variability. Although it is well defined at the surface on the equator by a salinity front and a sharp variation of the partial pressure of CO2, data from two equatorial cruises make it clear that this hydrological limit does not necessarily coincide with the boundary of the nitrate and chlorophyll enriched area. In January-February 1991 during a non-El Niño period, when trade winds and the South Equatorial current (SEC) were favorable to upwelling, the two limits were at the same longitude. Conversely, in September-October 1994 during El Niño conditions, when the equatorial upwelling had stopped, the nitrate and chlorophyll enriched zone was found a few degrees of longitude east of the hydrological boundary (5.5° at the surface and 2.5° for the 50 m upper layer), whereas no such offset was observed for zooplankton biomass. A simple model, based on the HNLC (High Nutrient - Low Chlorophyll) ecosystem functioning, was initialized with nitrate uptake measurements and estimates of upwelling break duration. The model results support the hypothesis that zonal separation of the limits arises from biological processes (i.e. nitrate uptake and phytoplankton grazing) achieved during that upwelling break. 相似文献
17.
Comparative analysis of the North Atlantic surface circulation reproduced by three different methods
K. V. Lebedev A. S. Sarkisyan O. P. Nikitin 《Izvestiya Atmospheric and Oceanic Physics》2016,52(4):410-417
Calculation results are presented for long-term mean annual surface currents in the North Atlantic based on direct drifter measurements and numerical experiments with the ocean general circulation model using both climatic arrays of hydrological data World Ocean Atlas 2009 and Argo profiling data. The calculations show that the technique suggested for model calculations of oceanographic characteristics of the World Ocean with the use of Argo data significantly improves the climatic fields of the temperature and salinity even on a coarse grid. The comparison of the model calculation results with drifter data showed that the temperature and salinity fields found from Argo data with the use of data variational interpolation on a regular grid allow the calculation of realistic currents and can be successfully used as initial conditions in hydrodynamic models of the ocean dynamics. 相似文献
18.
A numerical experiment with assimilation of hydrological observational data from a survey in October 2007 on the northwestern shelf of the Black Sea was carried out using the hydrodynamic model with nonlinear equations of motion, equations of heat and salt advection, and data assimilation. The results of this calculation are compared with thermohydrodynamic fields obtained without taking into account temperature and salinity measurements. It is shown that allowance for the observation data leads to qualitative and quantitative differences in the structure of the hydrophysical fields. Mesoscale eddies and intense jet streams that agree with satellite observations were found in the field of currents and were investigated. These eddies are not resolved in low-resolution field experiments. 相似文献
19.
The analysis of the thermochaline (double-diffusive) convection in the edge-ice zone of the Barents Sea to the east of Spitsbergen was performed by using the data of two hydrological surveys of the Norwegian Polar Institute in 1999 and 2000. The Turner's model, where the critical Rayleigh number is determined by using the empirical relationship between the Nusselt number and the Rayleigh number normalized to its critical value, was used for analysis. The results of calculation of thickness of the convective layer were compared with the data of supervision. The estimates of the vertical convective velocity were obtained. 相似文献
20.
Forecast of storm surge by means of artificial neural network 总被引：1，自引：0，他引：1
Marzenna Sztobryn 《Journal of Sea Research》2003,49(4):317
This study describes the construction and verification of a model of sea level changes during a storm surge, applying artificial neural network (ANN) methodology in hydrological forecasting in a tideless sea where the variation of water level is only wind generated. Some neural networks were tested to create the forecast model. The results of ANN were compared with observed sea-level values, and with the forecasts calculated by different routine methods. The results of verification show that the neural network methodology could be successfully applied in the routine, operational forecast service. 相似文献