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The problem of numerical modeling and analysis of the large-scale World Ocean circulation variability under variations of
the external forcing is considered. A numerical model was developed in the INM RAS and is based on the primitive equations
of the ocean circulation written in a spherical generalized σ-coordinate system. The model’s equations are approximated on
a grid with resolution of 2.5° × 2° × 33, and the North Pole is displaced to the continental point (60°E, 60.5°N). There are
two stages for the numerical experiments. The quasi-equilibrium circulation of the World Ocean under the climatological atmospheric
forcing is simulated at the first stage. The run is carried out over a period of 3000 years during which a quasi-equilibrium
model regime is formed. At the second stage, the sensitivity of the model ocean circulation to the atmospheric forcing perturbations
in the Southern Hemisphere is studied. According to the results, the strongest regional changes in the hydrography take place
in the Arctic Ocean. Substantial changes of sea’s surface height and local anomalies of the temperature and salinity are formed
there. 相似文献
3.
Ju. V. Artamonov A. V. Fedirko E. A. Skripaleva 《Izvestiya Atmospheric and Oceanic Physics》2016,52(9):1051-1063
Based on the satellite altimetry dataset of sea level anomalies, the climatic hydrological database World Ocean Atlas-2009, ocean reanalysis ECMWF ORA-S3, and wind velocity components from NCEP/NCAR reanalysis, the interannual variability of Antarctic Circumpolar Current (ACC) transport in the ocean upper layer is investigated for the period 1959–2008, and estimations of correlative connections between ACC transport and wind velocity components are performed. It has been revealed that the maximum (by absolute value) linear trends of ACC transport over the last 50 years are observed in the date-line region, in the Western and Eastern Atlantic and the western part of the Indian Ocean. The greatest increase in wind velocity for this period for the zonal component is observed in Drake Passage, at Greenwich meridian, in the Indian Ocean near 90° E, and in the date-line region; for the meridional component, it is in the Western and Eastern Pacific, in Drake Passage, and to the south of Africa. It has been shown that the basic energy-carrying frequencies of interannual variability of ACC transport and wind velocity components, as well as their correlative connections, correspond to the periods of basic large-scale modes of atmospheric circulation: multidecadal and interdecadal oscillations, Antarctic Circumpolar Wave, Southern Annual Mode, and Southern Oscillation. A significant influence of the wind field on the interannual variability of ACC transport is observed in the Western Pacific (140° E–160° W) and Eastern Pacific; Drake Passage and Western Atlantic (90°–30° W); in the Eastern Atlantic and Western Indian Ocean (10°–70° E). It has been shown in the Pacific Ocean that the ACC transport responds to changes of the meridional wind more promptly than to changes of the zonal wind. 相似文献
4.
N. G. Iakovlev E. M. Volodin A. S. Gritsun 《Izvestiya Atmospheric and Oceanic Physics》2016,52(4):376-385
The results of simulations of the World Ocean sea surface hight (SSH) in by various versions of the Climate Model of the Institute of Numerical Mathematics, Russian Academy of Sciences, are compared with the CNES-CLS09 fields of the mean dynamic topography (deviation of the ocean level from the geoid). Three models with different ocean blocks are considered which slightly differ in numerical schemes and have various horizontal spatial resolution, i.e., the INMCM4 model, which participated in the Climate Model Intercomparison Project (CMIP Phase 5, resolution of 1° × 1/2°); the INMCM5 model, which participates in the next project, CMIP6 (resolution of 1/2° × 1/4°); and the advanced INMCM-ER eddy-resolving model (resolution of 1/6° × 1/8°). It is shown that an increase in the spatial resolution improves the reproduction of ocean currents (with Agulhas and Kuroshio currents as examples) and their variability. A probable cause of relatively high errors in the reproduction of the SSH of Southern and Indian oceans is discussed. 相似文献
5.
A. S. Sarkisyan 《Izvestiya Atmospheric and Oceanic Physics》2012,48(1):1-14
This paper presents a brief critical analysis of the main historical stages of numerical modeling for the last fifty years. It was a half a century ago that the numerical simulation of an actual baroclinic ocean was initiated by the author and his students [1, 2]. In meteorology, studies on the numerical modeling of a baroclinic atmosphere existed much earlier [21, 22]. Despite this, a similar move in oceanography was met with strong resistance. At that time, there were many studies on the calculation of the total mass transport. The founders of this field, V.B. Shtokman, H. Sverdrup, and W. Munk, were mistaken in believing that they addressed baroclinic models of the ocean. The author preferred works by V. Ekman [12] and I. Sandström and B. Helland-Hansen [19]. A generalization of recent studies made it possible to come to some conclusions on the need to use the level of the free oceanic surface as a basis rather than the function of total mass transport, on the role of the baroclinic β effect (BARBE), on the joint effect of baroclinicity and bottom relief (JEBAR), etc. The author conditionally divides these fifty years into the following three stages. (1) The first stage was 1961–1969, when the author and his students performed almost exclusively diagnostic and adaptation calculations of climatic characteristics. (2) The second stage began with papers by K. Bryan [23] and his students. This is an important and promising stage involving mainly prognostic studies and four-dimensional analysis. The major advances in modeling at this stage (the Gulf Stream separation point [61], the Kuroshio seasonal evolution [63], the formation of the cold intermediate layer in the Black Sea [80], the subsurface countercurrent in the Caspian Sea [25], the realistic four-dimensional analysis of the Kara Sea [60], etc.) were due to high-resolution and/or data assimilation with an adequate period of integration. (3) The third stage began with the activities of international intercalibration programs such as the Arctic Ocean Model Intercomparison Project (AOMIP), the Global Ocean Data Assimilation Experiment (GODAE), Coordinated Ocean-Ice Reference Experiments (COREs), etc. Despite some defects initially, this is the most significant stage. For example, there is still very little data on GODAE, and COREs data are often used for a comparison of integral characteristics, the reliability of which cannot be established by direct measurements. 相似文献
6.
V. N. Zyryanov 《Oceanology》2007,47(5):618-625
Manifestation of the pumping effect (pump up/pump down) in the periodic problem of nonlinear heat conductivity was studied theoretically for the temperature of the deep layers averaged over the latitude and longitude of the World Ocean. It was shown that the pumping effect in the World Ocean is negative; i.e., when the amplitude of the sea surface temperature (SST) fluctuations increases, the temperature in its depths decreases. Thus, heat is pumped from the depths. Vice versa, if the amplitude of the SST fluctuations decreases as compared with the previous period, the temperature in the depths of the ocean increases; i.e., heat is pumped into the deep layers of the ocean. The period of climate warming is characterized by an increase in the amplitude of the interannual SST fluctuations, which, according to the theory developed, should lead to the cooling of the deep layers of the World Ocean. 相似文献
7.
Interannual variability of upwelling indices in the Southeastern Arabian Sea: A satellite based study 总被引：2，自引：0，他引：2
Chiranjivi Jayaram Neethu Chacko K. Ajith Joseph A. N. Balchand 《Ocean Science Journal》2010,45(1):27-40
Increase in sea surface temperature with global warming has an impact on coastal upwelling. Past two decades (1988 to 2007) of satellite observed sea surface temperatures and space borne scatterometer measured winds have provided an insight into the dynamics of coastal upwelling in the southeastern Arabian Sea, in the global warming scenario. These high resolution data products have shown inconsistent variability with a rapid rise in sea surface temperature between 1992 and 1998 and again from 2004 to 2007. The upwelling indices derived from both sea surface temperature and wind have shown that there is an increase in the intensity of upwelling during the period 1998 to 2004 than the previous decade. These indices have been modulated by the extreme climatic events like El-Nino and Indian Ocean Dipole that happened during 1991–92 and 1997–98. A considerable drop in the intensity of upwelling was observed concurrent with these events. Apart from the impact of global warming on the upwelling, the present study also provides an insight into spatial variability of upwelling along the coast. Noticeable fact is that the intensity of offshore Ekman transport off 8°N during the winter monsoon is as high as that during the usual upwelling season in summer monsoon. A drop in the meridional wind speed during the years 2005, 2006 and 2007 has resulted in extreme decrease in upwelling though the zonal wind and the total wind magnitude are a notch higher than the previous years. This decrease in upwelling strength has resulted in reduced productivity too. 相似文献
8.
R. Yu. Tarakanov E. G. Morozov A. M. Gritsenko T. A. Demidova N. I. Makarenko 《Oceanology》2013,53(4):432-441
The structure of northerly overflow of Antarctic Bottom Water (AABW) through passages in the East Azores Ridge (37° N) in the East Atlantic from the Madeira Basin to the Iberian Basin is studied on the basis of hydrographic measurements carried out by the Institute of Oceanology, Russian Academy of Sciences (RAS) in October 2011, historical World Ocean Data Base 2009, and recent data on the bottom topography. The overflow of the coldest layers of this water occurs through two passages with close depths at 16° W (Discovery Gap) and at 19°30′ W (nameless Western Gap). It is shown that it is likely that the role of the latter passage in water transport was underestimated in earlier publications because the water (2.01°C) found in the region north of the Western Gap was cooler than in the region north of the Discovery Gap (2.03°C). In 2011, we found a decrease of 0.01°C in the AABW temperature near the bottom compared to previous measurements in 1982 (from 2.011°C to 2.002°C). Analysis of the historical database shows that this decrease is most likely caused by the cooling trend in the abyssal waters in the East Atlantic basins. 相似文献
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The dynamic importance of the Southern Indian Ocean (SIO) lies in the fact that it connects the three major world oceans: the Pacific, Atlantic, and Indian Oceans. Modeling study has been used to understand the circulation pattern of this very important region. Simulation of SIO (10°N–60°S and 30°E–120°E) is performed with z-coordinate Ocean General Circulation Model (OGCM) viz; MOM3.0 and the results have been compared with observed ship drift data. It is found that except near coastal boundaries and in equatorial region, the simulated current reproduce most well known current pattern such as Antarctic Circumpolar Current (ACC), South Equatorial Current (SEC) etc. and bears a resemblance to that of the observed data; however the magnitude of the surface current is weaker in model than the observed data, which may be due to deficiency in the forcing field and boundary condition and problem with observed data. The annual mean wind stress curl computed over the oceanic domain reveals about ACC and its similar importance. The way in which the ocean responds to the windstress and vertically integrated transport using model output is fascinating and rather good. 相似文献
12.
We describe the space-and-time structure of large-scale thermal anomalies in the upper layer in the tropical zone of the Indian
Ocean and study the mechanism of their formation. It is shown that the critical layer in which the phase velocities of propagation
of disturbances coincide with the mean velocity of the zonal current can be formed in the central part of equatorial zone
of the Indian Ocean (between 9° and 12°S). In this layer, the formation of growing disturbances is possible due to the barotropic-baroclinic
instability of the system of zonal currents. 相似文献
13.
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
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A global eddy-permitting ocean-ice coupled model with a horizontal resolution of 0.25 by 0.25 is established on the basis of Modular Ocean Model version 4 (MOM4) and Sea Ice Simulator (SIS). Simulation results are compared with those of an intermediate resolution ocean-ice coupled model with a horizontal resolution of about 1 by 1 . The results show that the simulated ocean temperature, ocean current and sea ice concentration from the eddy-permitting model are better than those from the intermediate resolution model. However, both the two models have the common problem of ocean general circulation models (OGCMs) that the majority of the simulated summer sea surface temperature (SST) is too warm while the majority of the simulated subsurface summer temperature is too cold. Further numerical experiments show that this problem can be alleviated by incorporating the non-breaking surface wave-induced vertical mixing into the vertical mixing scheme for both eddy-permitting and intermediate resolution models. 相似文献
16.
The summertime phytoplankton bloom near the Kerguelen Plateau is in marked contrast to the low-chlorophyll conditions typical of the Southern Ocean and is thought to arise from natural iron fertilisation. The mechanisms of iron supply to the euphotic zone in this region are poorly understood, and numerical studies of iron transport have until now omitted fine-scale (sub-mesoscale) dynamics which have been shown to significantly increase vertical transport in other parts of the ocean.We present the first sub-mesoscale-resolving study of the flow and vertical transport in this region. The modelled transport and flow structure agree well with observations. We find that an increase in horizontal resolution from mesoscale-resolving (1/20°) to 1/80° resolves sub-mesoscale filamentary frontal structures in which vertical velocities are dramatically higher and are consistent with available observations. Lagrangian tracking shows that water is advected to the surface from much greater depth in the sub-mesoscale-resolving experiment, and that vertical exchange is far more rapid and frequent. This study of sub-mesoscale vertical velocities sets the foundation for subsequent investigation of iron transport in this environment. 相似文献
17.
We analyze the space-and-time variability of the meridional heat transport in the North Atlantic. The contribution of various
mechanisms to the integral meridional heat transport (MHT) is estimated. The key role played by the drift transport of the
Tropical Atlantic in the formation of the meridional oceanic heat transport is confirmed. On the basis of the general analysis
of estimations obtained by various authors according to the data accumulated for 1870–2008 and the results of numerical analyses
based on the data of NCEP/NCAR reanalysis, we show that the long-term average meridional drift heat (mass) transport attains its maximum values equal to (1.6 ± 0.1)
PW [(17.4 ± 1.5) Sv] in the vicinity of 12.5°N in the Tropical Atlantic. The contribution of the heat transport caused by
the horizontal Sverdrup circulation to the integral meridional heat transport is maximum in the vicinity of 30° N. On the
average, it is equal to ∼ 40%. In the Subtropical Atlantic, the meridional heat transport varies with a period of ∼ 50–70 yr.
The minimum value of the integral meridional heat transport was attained in the mid-1960s and its maximum value was at attained
at the beginning of the 1990s. The location of the center of Azores pressure maximum makes it possible to conclude that the
intensification of the total meridional heat transport in the Subtropical Atlantic on these time scales is accompanied by
the displacement of the center of the North Subtropical anticyclonic gyre in the southwest direction. 相似文献
18.
HOAPS-3 and PMWC satellite archives for 1988–2008 are used to estimate moisture-exchange components between the ocean and atmosphere (evaporation, precipitation, and the difference between them or effective evaporation). Moisture-exchange components for the entire World Ocean and for the North Atlantic Ocean within 30°–60° N are calculated. A strong overestimation of the global values of effective evaporation by HOAPS data (mainly caused by a decrease in precipitation) is shown. In the interannual variability of effective evaporation, there is clearly an overestimated positive trend, which contradicts the real increase in the Global Sea Level. Large systematic errors in moisture-exchange components are revealed for the North Atlantic water area. According to HOAPS data, there is a significant underestimation of evaporation and effective evaporation. According to PMWC data, the amount of precipitation is significantly overestimated and evaporation is underestimated. As a consequence, effective evaporation becomes negative, which is impossible. Low accuracy in the estimation of moisture-exchange components and the need to improve old estimates and develop new evaporation and precipitation databases based on satellite data are noted. 相似文献
19.
Verification of the wind-driven transport in the North Pacific subtropical gyre using gridded wind-stress products 总被引：1，自引：1，他引：0
Wind-stress products supplied by satellite scatterometers carried the European Remote-sensing Satellite (ERS) and QuikSCAT
(QSCAT), together with numerical weather predictions from the European Centre for Medium Range Weather Forecasting (ECMWF)
and the National Centre for Environmental Prediction (NCEP) were used to estimate wind-driven transports of the North Pacific
subtropical gyre. At 30°N, we compared the wind-driven transports with geostrophic transports calculated from World Ocean
Database 2005. The wind-driven transports for QSCAT and NCEP are in good agreement with the geostrophic transport within reasonable
error, except for a regional difference in the eastern part of the section. The difference in the eastern part suggests an
anti-cyclonic deviation of the geostrophic transport, resulting from an anti-cyclonic anomalous flow in the surface layer.
It is suggested that this anomalous flow is the Eastern Gyral, produced by the thermohaline process associated with the formation
of the Eastern Subtropical Mode Water. To investigate the validity of QSCAT and NCEP data, we examined whether or not the
Sverdrup transports for these products are consistent with the transport of the western boundary current estimated by past
studies. The net southward transport, given by the sum of the Sverdrup transport for QSCAT and NCEP and the thermohaline transport,
agrees well with the net northward transport of the western boundary current. From this result, together with the fact that
the wind-driven transports for these products are in good agreement with the geostrophic transport, we conclude that the Sverdrup
balance can hold in the North Pacific subtropical gyre. 相似文献
20.
V. B. Zalesny V. I. Agoshkov V. P. Shutyaev F. Le Dimet B. O. Ivchenko 《Izvestiya Atmospheric and Oceanic Physics》2016,52(4):431-442
Models and methods of the numerical modeling of ocean hydrodynamics dating back to the pioneering works of A.S. Sarkisyan are considered, with emphasis on the formulation of problems and algorithms of mathematical modeling and the four-dimensional variational assimilation of observational data. An algorithm is proposed for studying the sensitivity of the optimal solution to observational data errors in a seasurface temperature assimilation problem in order to retrieve heat fluxes on the surface. An example of a solution of the optimal problem of the World Ocean hydrodynamics with the assimilation of climatic temperature and salinity observations is offered. 相似文献