The variability of the dome-like form position of the Weddell Sea Deep Water (WSDW) has been studied based on ORAS5 datasets. According to these data, the upper boundary of the deep water occupied the highest position during most of 2005, and the lowest position in 2014 relative to its mean for 1993–2023. This change occurred because of the intensification of negative wind vorticity in 2005 and its weakening in 2014. Between 1993 and 2023, a permanent water transport from the Weddell Sea to the Scotia Sea was detected over the depth corresponding to the sill in the Orkney Passage in the ORAS5 data. In 2005, this transport was almost unchanged, whereas in 2014 it became stronger. When the dome boundary of WSDW moves up in the central part of the Weddell Sea, the outer parts of the dome move down, and vice versa. In the northern part of the Weddell Sea, this motion of isotherms and isopycnals causes either colder or warmer water parts of the WSDW column to overflow the crest of the South Scotia Ridge and continue its motion in the Scotia Sea.

In this model study, we address the probability of rapid reorganization of thermohaline structure and circulation in the Arctic (AO) and North Atlantic (NA) oceans under the prolonged unidirectional atmospheric forcing over the AO. The relevance of such investigation is dictated by the presence of huge volume of surplus fresh water accumulated in the Beaufort Gyre (BG) of the Canada Basin for the past 30 years due to extremal sea ice melting and increased river runoff. In hypothetical case of rapid release to the NA, this fresh water volume may at least cause strong salinity anomaly similar to the Great Salinity Anomaly in the 1970s. Taking into account that the subpolar NA is the key locus of the deep water formation feeding the southward branch of the Atlantic Meridional Overturning Circulation (AMOC), the excess freshening at the ocean surface may negatively affect the AMOC intensity. To check up the validity of this hypothesis, we carried out the two idealized model experiments with opposite atmospheric forcings over the AO: the so-called “cyclonic” one, which favors intensive NA–AO water exchange, and the “anticyclonic” one, which impedes such an exchange. We chose the two actual years with extremal forcings (1989 as a cyclonic one, and 2004 as an anticyclonic one) and artificially applied them for the 10-year period assuming that such a duration is at the margin of physical realism. Our major finding, within the limitations of numerical experiments on the OGCM (Ocean General Circulation Model) INMOM (Institute of Numerical Mathematics Ocean Model), shows that anomalously long preservation of “cyclonic” forcing over the AO is able to substantially rearrange salinity in the upper ocean layer. However, it may not trigger massive “instant” outflow of freshwater through the Fram and Denmark Straits, since a large portion of accumulated in the BG freshwater spreads around the AO following the surface circulation pattern without reaching the Fram Strait. However, the tendency of the upper ocean layer freshening in the subpolar NA due to freshwater flushing from the AO is confirmed.

In contrast to fairly good knowledge of seasonal and interannual variability in North Atlantic salinity, its long-term historical changes remain poorly characterized, making it difficult to assess the current state and possible future changes. To fill this gap, we present the results of applying a non-parametric method of regression analysis (quantile regression) to assess long-term changes in North Atlantic salinity (0°–70° N, 8°–80° W) based on multiple datasets. The features of quantile trends in monthly salinity for a median value in two periods (1948–2018 and 1961–2011) are considered. In 1948–2018, salinization was generally detected in North Atlantic tropical and subtropical latitudes, while desalination was found in subpolar latitudes. For the 71-year period under consideration, the median monthly salinity in subtropical latitudes increased by 0.07±0.02 PSU. Over the period 1961–2011, pronounced long-term changes in the North Atlantic salinity are difficult to identify based on the datasets used. A consistency analysis of significant salinity trends across the most used datasets allowed us to detect five small areas with pronounced positive trends in the upper ocean salinity. These include the Guiana Current, the vicinity of 12° N, 48° W, the Canary upwelling area, the region of the Gulf Stream transition to the North Atlantic Current and the western part of the North Atlantic Subpolar Gyre. In these areas, over a 51-year period, salinity in the 10–400 m layer increased by an average of 0.10±0.04 PSU.

The present-day climate (the recent 100–150 years) obviously constitutes the structure of a global intra-system rhythmic process with an individual rhythm of about 60 years. In turn, each of the rhythms is presented by the two climate phases of about 25–35 years characterized by qualitative differences: one phase is relatively continental, while the other is humid. Globality and quasi-synchronism of environmental changes are accompanied by planetary structures: the Global Atmospheric Oscillation (GAO) in the atmosphere and the Multidecadal Oscillation of the Heat content in the Ocean (MOHO) discovered relatively recently. Unexpected and rapid qualitative phase changes in the climate, which first focused attention in the mid-1970s of the last century, were titled “climate shifts”. The revealed features of the present-day climate are of exceptional scientific and practical interest and deserve the development of methods for predicting the timing of the forthcoming climate shift. Arising unexpectedly and accompanied by rapid significant changes, these shifts identified the problem of understanding the nature and establishing the processes and mechanisms causing them. First of all, of interest are phase changes in the thermodynamic state of the climate system components: the ocean, atmosphere, and continents. As a result of the World Ocean (WO) thermohydrodynamics numerical modelling, it is shown that MOHO is localized in the layer of the main thermocline, where the most important elements of the WO circulation are located. The performed study based on observational data allows us to conclude that, during the phase of the WO thermal discharge (1975–1999), the two key systems of currents, the Kuroshio and the Gulf Stream, were under similar thermodynamic conditions.

The modern climate is the climate of the current century with its characteristic features. The ocean and the atmosphere, however, are considered as two of the most important components of the climate system. The dynamics and thermodynamics of these spheres reflect the current perturbations of the planetary environment on intra-decadal (2–8 years) and multi-decadal (20– 60 years) time scales. Quasisynchrony and globality of the phenomena occurring in the modern climate system are provided and accompanied by planetary scale structures identified both in the atmosphere and in the ocean: respectively, the Global Atmospheric Oscillation (GAO) and the Multi-decadal Oscillation of the Heat content in the Ocean (MOHO). A characteristic feature of the modern climate dynamics is its observed multidecadal rhythm with a period of about 60 years. The rhythm of 1940–1999 was a two-phase structure, in which the initial phase (1940–1974) was essentially continental, and the final one (1975-1999) was relatively wet. The transition of the climate from the continental phase to the humid phase in the mid-1970s turned out to be “sudden” and was recognized as a climate shift. The search for the source of the observed variability of the modern climate made it possible to establish that the heat content of the active upper layer (AUL) of the World Ocean (WO) demonstrates multidecadal phases of heat accumulation and heat discharge, consistent with multi-decadal phases of climate disturbances. It should be noted that the heat accumulation phase of the WO AUL corresponds to a continental climate, and its thermal discharge corresponds to a relatively humid one. The mechanism of the observed multidecadal phase variability of the modern climate is the planetary intrasystem redistribution of heat between WO and continents, in which the general circulation of the atmosphere plays the role of a mediator.

In this model study, we address the feasibility of rapid shutdown or, at least, substantial weakening of the Global Circulation Conveyor (GCC) caused by massive discharge of freshwater to the northern North Atlantic (NA). The source of this freshwater excess is the permanently ice-covered Arctic Ocean (AO), while its release may be caused by ice melting and intensified river runoff due to global warming. To check up the validity of this hypothesis, we carried out the two idealized experiments with opposite atmospheric forcings over the AO: the so-called "cyclonic" one, which favors intensive water exchange between the AO deep interior and the Nordic Seas (NS), and "anticyclonic" one, which impedes this exchange. We chose the two actual years with extremal forcings (1989 as cyclonic one, and 2004 as anticyclonic one) and artificially applied these forcings during the 10-year period assuming that such a duration is at the margin of physical realism. Our major finding, within the limitations of numerical experiments on the OGCM (Ocean General Circulation Model) INMOM (Institute of Numerical Mathematics Ocean Model), shows that anomalously long preservation of "cyclonic" forcing over the AO is able to substantially rearrange salinity in the upper ocean layer. However, it may not trigger massive "instant" outflow of freshwater through the Fram and Denmark Straits, since a large portion of accumulated in the Beaufort Gyre freshwater spreads around the AO following the circulation without reaching the Fram Strait. However, the tendency of the upper ocean layer freshening in the northern NA due to flushing of freshwater from the AO is confirmed in consistency with the basic concept of the GCC hiatus.

An upgraded version of the OGRAN combined optical-acoustic gravitational wave detectorhas been investigated in a long-term operation mode. This installation, located at the Baksan Neutrino Observatory (BNO) INR RAS, is designed to work under the program for detecting collapsing stars in parallel with the neutrino detector: Baksan Underground Scintillation Telescope (BUST). Such joint search corresponds to the modern trend for a development of “multi-messenger astronomy”. In this work the effects of thermal relaxation OGRAN are experimentally investigated using passive and active thermal stabilization systems in the underground laboratory BNO PK-14.

A Specific feature of the present-day climate dynamics consists in its multidecadal oscillations with a period of about 20–60 years, and intradecadal disturbances with time scales of 2–8 years. The period of 1940–1999 was distinctive due to the two–phase structure in which the initial phase (1940–1974) was substantially dry, and the final one (1975–1999) was relatively humid. The transition of the climate from the dry to the humid phase in the mid-1970s was recognized as a climatic shift. The certain globality and quasisynchronism of multidecadal climate changes occur involving planetary thermodynamic structures in the two most important components of the climate system, namely, the ocean and the atmosphere. The search for the origin of the observed present-day climate variability revealed the World Ocean (WO) active upper layer (AUL) heat content to demonstrate sequential multidecadal phases of heat accumulation and discharge consistent with multidecadal phases of climate disturbances. Thus, the WO AUL heat accumulation phase corresponds to a dry climate, and its thermal discharge corresponds to a relatively humid one. The mechanism of the observed multidecadal phase variability in the present-day climate consists of the planetary intrasystemic redistribution of heat between WO and continental air masses, where the general circulation of the atmosphere plays the role of an intermediary.

The first part of the paper presents verification results of the technology developed at the Federal State Budgetary Institution “N. N. Zubov State Oceanographic Institute” (FSBI “SOI”) – Marine Hindcast and Forecasts System (MHFS) adapted for the Kerch Strait. It represents the complex of numerical regional models of the atmosphere, marine circulation, dynamics-thermodynamics of ice cover and wind waves for the Sea of Azov and Kerch Strait., marine circulation models of the MHFS were implemented with a high spatial resolution. This technology was used to support the design and construction of the bridge across the Kerch Strait. The capabilities of reproduction of the hydrological characteristics required for practical purposes are demonstrated by verification of model results with observational data. It is supposed to use the presented technology of calculation of hydrometeorological parameters of Kerch Strait for the monitoring system developed within the framework of the Russian Science Foundation research project 21-17-00191 “Monitoring of water exchange through the Kerch Strait on the basis of modern methods of observations and numerical modeling”. The second part will present the regime characteristics of hydrological conditions in the Kerch Strait water area.

An algorithm for taking into account salt fluxes through the open boundary of the simulated water area, that is based on the method of variational data assimilation, is proposed. The results of the numerical experiment on simulating the major Baltic inflow that occurred in December 2014 are presented. The experiment utilized the Baltic Sea hydrodynamic model developed on the basis of the INMOM ocean and sea circulation model with implementation of the proposed algorithm. A comparison between the simulation results obtained using the algorithm and the results obtained by relaxation to observational data is carried out.

The driving mechanisms of mesoscale processes and associated heat transport in the Japan/East Sea (JES) from 1990 to 2010 were examined using eddy-resolving ocean model simulations. The simulated circulation showed correctly reproduced JES major basin-scale currents and mesoscale dynamics features. We show that mesoscale eddies can deepen isotherms/isohalines up to several hundred meters and transport warm and low salinity waters along the western and eastern JES boundaries. The analysis of eddy kinetic energy (EKE) showed that the mesoscale dynamics reaches a maximum intensity in the upper 300 m layer. Throughout the year, the EKE maximum is observed in the southeastern JES, and a pronounced seasonal variability is observed in the southwestern and northwestern JES. The comparison of the EKE budget components confirmed that various mechanisms can be responsible for the generation of mesoscale dynamics during the year. From winter to spring, the baroclinic instability of basin-scale currents is the leading mechanism of the JES mesoscale dynamics’ generation. In summer, the leading role in the generation of the mesoscale dynamics is played by the barotropic instability of basin-scale currents, which are responsible for the emergence of mesoscale eddies, and in autumn, the leading role is played by instabilities and the eddy wind work. We show that the meridional heat transport (MHT) is mainly polewards. Furthermore, we reveal two paths of eddy heat transport across the Subpolar Front: along the western and eastern (along 138∘ E) JES boundaries. Near the Tsugaru Strait, we describe the detected intensive westward eddy heat transport reaching its maximum in the first half of the year and decreasing to the minimum by summer.

The contributions of wind and thermohaline factors to the formation of the mean climatic structure of the Antarctic Circumpolar Current (ACC) were studied using numerical simulations with the INMOM ocean general circulation model. The goal of our research was to separate the wind and thermohaline ACC components. The simulations were carried out for summer (February) and winter (August) conditions. The ACC structure of three jets was revealed by numerical simulations using the diagnosis-adjustment approach to the EN4 climatic data of observations. Wind circulation in the surface layer turns to the left with respect to the direction of wind stress (southern hemisphere) according to Ekman’s theory. Due to the stronger winds in winter, the response of drift velocities is stronger than in summer. It is shown that, in spite of strong winds over the Southern Ocean, the thermohaline factor of circulation is generally much stronger than the drift factor. Nevertheless, the contribution of the wind component to the increase in the zonal velocity in the Drake Passage near Antarctica can be as high as 15–20% of the thermohaline velocity in the upper layer. Wind contributes to a decrease in the mean dynamic topography (MDT) by more than 6 cm from the open ocean to the Antarctic coast. The MDT decrease caused by thermohaline factors over this distance exceeds 2 m, which agrees well with the finding that the contribution of thermohaline factors to the ACC dynamics significantly exceeds the contribution of wind. However, winds are subjected to seasonal variations. The effect of wind on the formation of the barotropic stream function is more pronounced than on the MDT. Thermohaline transport in the Drake Passage is almost the same (~110 Sv) in winter and summer. Due to wind forcing, the total ACC transport around Antarctica increases on average by 9–11 Sv in February and by 12–17 Sv in August. In the Drake Passage, the wind transport increases less than over the entire ACC: by 8 Sv in summer and by 12 Sv in winter. Thermohaline factors comprise a significantly greater contribution to the ACC dynamics than wind forcing. A three-jet structure of the ACC was revealed based on simulations using the INMOM model and EN4 data. It is shown that this three-jet structure of the ACC is of a thermohaline nature.

One of the most remarkable peculiarities of the modern climate, undoubtedly, should be recognized as the climatic shift observed in the mid-70s of the last century. The reasons for this phenomenon for a long time, despite the activation of climatologists from all over the world, remained a mystery that requires its disclosure. First of all, this was due to the fact that the shift that took place turned out to be unexpected for scientists and was accompanied by rapid qualitative changes in the planetary climate. To date, thanks to the efforts of scientists using the results of rapidly developing numerical modeling, diagnostic calculations and observational data in large hydrophysical experiments in various regions of the World Ocean (WO), an understanding of the role of the ocean factor in the variability of the current climate has developed. It became clear that climatic shifts are an important feature of the internal dynamics of the climate system. The most obvious evidence of intrasystemic processes should be considered the discovered planetary structures in the atmosphere – Global Atmospheric Oscillation (GAO) and in the ocean – Multi-decadal Oscillation of the Heat content in the Ocean (MOHO), which are quasi-synchronous accompanying variations in the modern climate. GAO, its structure and features have been discussed in detail earlier in a number of studies. As for the MOHO, its structure and features are discussed in the proposed work. It is characteristic that the MOHO is located in the layer of the main thermocline (100-600 m). In a quasi-uniform layer (0–100 m), and in a deep layer (600-5500 m), the thermodynamic regime differs from the regime in the layer of the main thermocline. Probably, it is precisely this circumstance that did not allow earlier to draw attention to such an important detail in the structure of the WO thermodynamic variability. The presence of extreme multi-decadal temperature field disturbances at intermediate levels (200, 300, 400, 500, 600 m) should be noted as an important characteristic feature of the oscillation. Large-scale hydrophysical experiments (POLYGON-70, POLYMODE, etc.) made it possible to reveal the vortex structure in the dynamics of WO waters and to discover that the vortices of the open ocean have maxima of kinetic energy precisely in the layer of the main thermocline. This allows us to assume a connection between synoptic eddy activity and MOHO. However, the latter remains to be studied.

Multi-decade rhythmicity is one of the most important features of the dynamics of the modern climate. The rhythm of 1940–1999 was a two-phase structure in which the initial phase (1940–1974) was essentially continental, and the final phase (1975–1999) was relatively wet. The transition of the climate from the continental phase to the humid one in the mid-70s of the twentieth century was “sudden” and recognized as a climate shift. A certain globality and quasi-synchronicity of multi-decade climate changes is realized with the participation of planetary thermodynamic structures both in the ocean and in the atmosphere of two the most important components of the climate system. The presence of a Global atmospheric oscillation was discovered and studied in detail. This paper offers the first attempt to consider the content and features of the planetary multi-decadal oscillation of the heat content of the World Ocean. The analysis of ocean oscillation is based on the results of numerical simulation of the World Ocean water circulation in the period from 1948 to 2007 using the model of the Marchuk Institute of Numerical Mathematics of Russian Academy of Sciences. The differences in the average water temperature fields in the upper 1200-meter layer, calculated for two opposite phases of the oscillation, revealed the main features of its structure.

The article discusses the reduction of harmful emissions into the environment, the production of organic (bio) products, with increasing demand from the population, describes the experience of using an adsorbent - activated carbon in poultry farming, and provides biochemical data on the effectiveness of our method. The authors analyze various types of pollution, highlighting the role and importance of harmful emissions in the agricultural sector. Moreover, as the researchers note, there is a demand for environmentally friendly agricultural products. The global environmental problems, a significant part of which is the utilization and use of litter, makes us look for ways to reduce harmful factors in poultry farming. On the other hand, the consumption of nitrogen fertilizers in crop production requires metered application. The use of organic fertilizers with the addition of adsorbents is more effective, since the desorption process allows you to saturate the soil with nitrogen gradually, without polluting the sown area.

The main purpose of the work is to improve the ocean general circulation model (OGCM) by including new parameterizations of heat, salt and momentum vertical turbulent exchange, which significantly affects quality of reproducing the ocean circulation and thermohaline structure using the OGCMs based on the primitive equation system. The main instrument of the research is the σ-model of the oceanic and marine circulation INMOM (Institute of Numerical Mathematics Ocean Model) developed at the Marchuk Institute of Numerical Mathematics of RAS. The basic equation set in the incompressibility, hydrostatics and Boussinesq approximations is supplemented with the equations for the k-ω and k-ε vertical turbulent exchange parameterizations, which are solved using the splitting with respect to the physical processes. The total equations are split into the stages describing transport-diffusion of the turbulent characteristics and their generation-dissipation. At the generation-dissipation stage, the equations for turbulent characteristics can be solved analytically. This approach allows one to solve the turbulence equations with the time step used in the OGCM. To estimate quality of these two vertical turbulent exchange parameterizations, the joint circulation of the North Atlantic and Arctic Ocean is numerically simulated and the upper ocean layer characteristics are studied. It is shown that the structure of large-scale fields in the North Atlantic and Arctic Ocean is sensitive to the choice between these two vertical turbulence models. In particular, application of the k-ε parameterization is accompanied by a noticeably higher rate of water involvement within the seasonal pycnocline in the developed turbulence zone than that resulting from application of the k-ω model. The investigation is carried out in the INM RAS and MHI RAS under support of the Russian Science Foundation (grant No 17-77-30001). References Moshonkin, S., Zalesny, V. and Gusev, A., 2018, Journal of Marine Science and Engineering, 6(95), https://doi.org/10.3390/jmse6030095 Zalesny, V.B., Moshonkin, S.N., Perov, V.L. and Gusev, A.V., 2019, Physical Oceanography, 26(6), 455-466, https://doi.org/10.22449/1573-160X-2019-6-455-466

Circulation patterns characterizing the variability of the dynamics of the active ocean layer describes in the regions of Greenland and Norwegian seas, in the Subpolar Gyre of the North Atlantic based on the analysis of numerical experiments for 1948–2009 with the model of the North Atlantic and the Arctic (step 0.25°, 40 levels). Density and current velocities anomalies were determined by subtracting the average annual cycle from the realizations for 0–300 m layer. Most covariant joint distributions (modes) for the spatiotemporal fields these anomalies defined by SVD analysis and investigated. An analysis of the structural, correlation, and dispersion characteristics of the main joint modes of variability of water density and current velocities anomalies is given. The second and third modes of circulation anomalies in the north of the Greenland Sea and in the Subpolar Gyre of the North Atlantic show the possibility of stabilizing the amplitude of the variability of heat and salt transport by currents and water exchange between the Atlantic and Arctic at a certain climatic level. These phenomena are characterized by the time scale from intra-monthly to six months in the north of the Greenland Sea. The change in the intensity of the anticyclonic water rotation in the Norwegian Basin balances the variability of the Atlantic Norwegian Current mass transport on a 2.5-year scale.

Н.А. Дианский1,2,3), И.В. Соломонова4), А.В. Гусев2,5) 1) Московский государственный университет им. М.В. Ломоносова, Москва 2) Институт вычислительной математики им. Г.И. Марчука РАН, Москва 3) Государственный океанографический институт им. Н.Н. Зубова, Москва 4) Институт водных проблем РАН, Москва 5) Институт океанологии им. П.П. Ширшова РАН, Москва nikolay.diansky@gmail.com, _iren@mail.ru, anatoly.v.gusev@gmail.com