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Vol 65, No 4 (2025)
Физика моря
Reconstruction of seasonal mean clouds over the world ocean using probabilistic distribution of clouds and singular spectra
Abstract
Development of the effective probability distribution functions for cloud cover data is critically important for the quantitative statistical description of cloud cover over the oceans, including the probabilities of various cloud regimes. We analyze applicability of probability distribution developed for visually observed cloud cover to satellite observations of the total cloud cover over the global oceans. Further we use parameters of probability distributions for quantifying cloud cover response to different factors. We utilized mixed Gamma distribution for approximation of the probability density of the total cloud cover. Further probability estimates derived from the theoretical distribution were used for developing predictive statistical metrics for five-year total cloud cover over the World Ocean. Global calculations were conducted for a 5° × 5° grid for the winter and summer seasons. Total cloud data were taken from the CLARA-A ed. 3 dataset retrieved from satellite measurements of AVHRR on the polar orbit satellites over the period from 1979 to 2023. The predictive distribution of total cloud cover was designed utilizing Singular Spectrum Analysis for N + 1 year with the test years ranging from 2019 to 2023. The forecasts were based on data records from 1979–2018, and each prediction for N + 1 year was next checked against the data for the respective test year. This procedure was applied for 5-year means for winter and summer seasons. Despite the use of a distribution function based on the incomplete Gamma function, prediction of the distribution of total cloud cover may have uncertainties of up to 2 octas, contingent to the dominant cloud cover regime. This discrepancy is due to poor capability of the distribution function to precisely capture abrupt changes in probability density of the cloud cover for specific cloud regimes.
Okeanologiâ. 2025;65(4):539-547
539-547
Behavior modes of a quasi-geostrophic ellipsoidal vortex in a horizontal flow with vertical shear
Abstract
The paper addresses the problem of the behaviour modes of baroclinic geostrophic vortices with ellipsoidal-shaped cores in horizontal flows with a vertical shift. In such flows, the vortex core is confined between two stationary horizontal planes, which the vortex touches at its upper and lower points. Under the influence of the background flow, the lengths of all the axes of the ellipsoid can change, and the angles of orientation of the vortex in space also change. The authors identify three modes of vortex behaviour. The first mode is the survival mode of the vortex in a shear flow, where the vortex undergoes finite oscillations of the semi-axes for an indefinite period of time and may exhibit complex behaviour in terms of its orientation angles. This mode corresponds to strong vortices. In the second mode, the vortex is stretched along the flow from the very beginning, remaining with finite horizontal dimensions perpendicular to the flow and compressed vertically. This is the destruction mode of the vortex by the flow, where the final result is the formation of a thin vertical structure of the ocean from the vortex. Weak vortices undergo this type of evolution. This mode is referred to as the “unlimited stretching mode.” Finally, there is a third mode, called the “finite lifetime mode,” in which, for a finite period of time, the vortex behaves similarly to the survival mode (its shape is finitely deformed, and the vortex rotates or oscillates in space), but eventually, the vortex stretches indefinitely in a manner similar to the destruction mode. The authors have delineated the regions of existence for each mode on a dimensionless parameter plane of the problem and determined the boundaries separating the above-mentioned modes of vortex behaviour.
Okeanologiâ. 2025;65(4):548-568
548-568
Parameterization of thermal structure of the Black Sea active layer at the Gelendzhik study site during warm period
Abstract
Using the long-term studies of the Black Sea thermal structure at the Gelendzhik study site, a parameterization of temperature profiles in the active layer was proposed for the warm period (May-November), based on ten-days averaging. It included variability of the upper mixed layer, its temperature and thickness. The 10-days grouping was performed for all studied years (2010–2023) simultaneously, with only day and month being taken into account, to remove synoptic variability and concentrate on general seasonal dynamics. The averaged temperature profiles were transformed into a dimensionless form and described as a universal power function of dimensionless depth. With a reverse transition back to dimensional variables, it was possible to reproduce an annual-average temperature profile in the seasonal thermocline for any particulate day from May to November. Assuming the temperature in the upper mixed layer being the same as at the uppermost part of the thermocline, a thermal structure of the entire active layer therefore could be reconstructed. Calculation examples for different decades are provided, along with comparison of real temperature profiles with the ten-days averaged and the formula-based.
Okeanologiâ. 2025;65(4):569-580
569-580
Diapycnal Exchange in the Main Pycnocline of the Black Sea
Abstract
The article discusses the application of G03 parameterization for calculating the vertical turbulent diffusion coefficient from vertical profiles of water density and current velocity. The work is based on the processing of data obtained during the 95th cruise of the R/V Professor Vodyanitsky with a depth resolution of about 10 meters in the central sector of the northern Black Sea from June 16 to July 4, 2017. Measurements of salinity and water temperature profiles were carried out using the SBE911plus probe, and current velocity – using the LADCP lowered acoustic Doppler current profiler. Transfer functions of the process of parameter measurement, calculation of vertical derivatives at finite increments and data processing were taken into account when integrating the canonical spectrum of internal waves. The results of calculating the vertical turbulent diffusion coefficient in the main pycnocline on the isopycnal surface with a conditional density of 15 kg/m3, which was characterized by a maximum buoyancy frequency, are considered in detail. Intensification of diapycnal mixing was observed in the area of the Rim Current. The value of the vertical turbulent diffusion coefficient at the maximum was 1.3 · 10–6 m2/s, in the center and on the periphery of the sea – 0.4 · 10–6 m2/s and 0.65 · 10–6 m2/s, respectively. Estimates of heat, salt and oxygen fluxes were also the highest in the area of the Rim Current. Fluxes in the center and on the periphery of the sea are 1.5–3 times less than their values at the maximum.
Okeanologiâ. 2025;65(4):581-588
581-588
Химия моря
First Data on Trace Element Composition of Water and Sediment in Watercourses and Lakes of the Novaya Zemlya Archipelago
Abstract
For the first time the results of determination of 44 trace elements in water and suspended solids of watercourses and lakes of 5 bays of Novaya Zemlya Archipelago (Blagopoluchiya, Tsivolki, Stepovogo, Abrosimova and Medvezhiego) are presented. Low concentrations of dissolved trace elements were revealed in comparison with their concentrations in the rivers of the Russian Arctic. This is due to significantly suppressed chemical weathering on the archipelago due to the harsh climate and peculiarities of watershed rocks, as well as increased activity of sorption processes and sharply reduced concentrations of dissolved organics. A different situation is observed in terms of the content of the same trace elements in suspended sediments of watercourses and lakes. The similarity in the content of chemical elements in suspended sediments of watercourses and lakes and the main sedimentary rocks of catchments – ankeritolitic shales – directly points to them as the most important source of dissolved and suspended matter input into watercourses and lakes. A comparison of dissolved trace elements in the watercourses and lakes of Novaya Zemlya and the Kolyma River showed that the watercourses and lakes are significantly poorer in trace elements than the Kolyma river.
Okeanologiâ. 2025;65(4):589-607
589-607
Features of Distribution and Composition of Organic Compounds in Bottom Sediments of the Kolyma Mouth Area
Abstract
The article presents the results of the study of chloroform bitumen (CB), organic carbon (Corg), aliphatic (AHСs) and polycyclic aromatic hydrocarbons (PAHs) in the bottom sediments of the Kolyma estuary. It study found that the sediments of the pier for small vessels in the village of Chersky, as well as in the port of Zeleny Mys, are the most polluted with oil products (according to the IR spectra, composition of alkanes and PAHs). In 2018, the concentrations varied in the range of 35–318 μg/g for AHСs, 37–970 ng/g for PAHs. In the sediments of the river itself and the Ambarchik Bay of the East Siberian Sea, the concentrations of hydrocarbons were significantly lower: 71–25 μg/g for AHCs, and 28–100 ng/g for PAHs, terrigenous compounds of natural origin dominated in their composition. Local hydrocarbon pollution settles in the mouth of the Kolyma and does not enter open sea waters (the influence of the riverʹs marginal filter is possible). In subsequent years, hydrocarbon concentrations in port waters changed depending on emissions of petroleum products.
Okeanologiâ. 2025;65(4):608-617
608-617
The effect of small doses of γ-radiation on carbon assimilation by a natural community of microplankton
Abstract
In the Kara Sea, a study was conducted on the effect of small doses of γ-radiation from an external source of 40K (Eγ=1.46 MeV) on the process of carbon assimilation by a natural population of microplankton. The results of measuring the rate of carbon assimilation by the plankton community under the influence of γ-radiation from external sources with an activity of 269 Bq and 376 Bq showed a multidirectional effect of its influence on carbon assimilation in the light and in the dark. In the surface layer, the rate of carbon assimilation in light samples with a source activity of 269 Bq increased by an average of 1.2 times. It was shown that with a γ-radiation source activity of 376 Bq, the average rate of carbon assimilation in the light increases by an average of 1.4 times. A comparison of the rate of dark carbon assimilation in γ-radiation from sources with an activity of 269 Bq and 376 Bq showed its decrease by an average of 1.6 times relative to the background, regardless of the dose rate.
Okeanologiâ. 2025;65(4):618-626
618-626
Морская биология
Intrapopulation variability of Artemia parthenogenetica Barigozzi, 1974 (Branchiopoda, Anostraca) cysts of the Kara-Bogaz-Gol Bay of the Caspian Sea (biometry)
Abstract
Cysts (resting stages) of the brine shrimp Artemia are used as live starter feed in aquaculture for breeding shrimp and valuable fish species. The data on cysts of Artemia parthenogenetic population – Artemia parthenogenetica (diameter of hydrated cysts, diameter of decapsulated cysts (embryos), and chorion thickness), sampled in the Kara-Bogaz-Gol Bay of the Caspian Sea, were analyzed. Significant intrapopulation variability in the cyst chorion thickness was established, as well as insignificant variability in the diameter of hydrated cysts and diameter embryos. The absolute values of the diameter of hydrated cysts were in the range of 226.0–288.6 μm, the mean values for the samples – 234.0–265.4 μm; the absolute values of the diameter of decapsulated cysts were in the range of 209.7–277.5 μm, the mean values for samples – 228.7–243.5 μm; the absolute values of the cyst chorion thickness were in the range of 0.7–27.7 μm, the mean values for samples –5.7–11.5 μm. It is shown that there is a strong positive reliable relationship between salinity and the studied biometric features. Significant variability in the diameter of hydrated cysts and the chorion thickness indicates that these morphological features cannot serve as reliable indicators for identifying this population; a smaller mean embryo diameter is a feature that distinguishes the Kara-Bogaz-Gol population of Artemia from other parthenogenetic populations. The range of known values of the cyst chorion thickness of Artemia parthenogenetic populations has been expanded to the larger side.
Okeanologiâ. 2025;65(4):627-637
627-637
Shrimp of the Sakhalin Bay (Sea of Okhotsk): Size and sex composition and nutrition in July-August 2016–2017
Abstract
In 10 samples from bottom trawling catches carried out in the Sakhalin Bay in July-August 2016–2017, 6 species of caridea shrimp were found at depths of 53–66 m: Eualus fabricii (Krøyer 1841), Lebbeus uschakovi (Kobjakova 1936), Spirontocaris intermedia Kobjakova 1936, S. murdochi Rathbun 1902, Pandalopsis lamelligera Brandt 1851 and Argis lar Owen 1839. The biological state of 796 shrimp samples was studied, including 466 stomachs with food for the analysis of food composition. These shrimps are inhabitants of the shelf and its edge to depths of 400 m and belong to different life forms: A. lar – burrowing. L. uschakovi, Spirontocaris spp. and E. fabricii – epibenthic, P. lamelligera – bottom-bottom. All of them differ in size composition and sex ratio, but at the same time, individuals preparing for spawning or just spawned absolutely predominate among the females: the periphery of the Sakhalin Bay, at least in July and August, represent the spawning ground of these shrimps. By the nature of their diet, they are collectors of benthic detritophages and benthic necrophages and predators.
Okeanologiâ. 2025;65(4):638-647
638-647
Summer Habitat of the Bearded Seal (Erignathus barbatus) in the Western Part of the Sea of Okhotsk
Abstract
Bearded Seal is a typical, widespread and numerous inhabitant of the Sea of Okhotsk. The western coastal waters of the Sea of Okhotsk is one of the main areas of its summer habitat. The bays of the Shantar Area, where bearded seal is concentrated in the summer, as shown by early researches, were not affected by the scientific studies after the end of the hunting. The proposed work summarizes a series of route surveys carried out in the summer in the area of the Shantar Archipelago. The results obtained show that bearded seals are, in general, rare in the bays adjacent to the Shantar Islands at the beginning of summer. Later, their numbers increase. By the end of July – beginning of August, the animals are already widespread in the bays and in the straits between the islands. From the second half of August, animals begin to gather on shallows and in shallow areas of bays, forming aggregations. Bearded seal forms the most numerous concentrations in the Gulf of Constantine. In the outer parts of the bays and in the straits between the islands during this period, animals are almost not found.
Okeanologiâ. 2025;65(4):648-653
648-653
Морская геология
Changes of terrigenous sediments in zones of contact with basalts (mouth of the California Gulf, hole DSDP 474/474A)
Abstract
The article presents the results of a study using a set of analytical methods of the mineral and chemical composition of sediments from the DSDP Hole 474/474A, 626 m deep, and their changes in contact zones with basalt sills. Jarosite, bassanite and anhydrite were formed in the sediments from these zones. In sediments located above the sill, the thickness of which is 6.73 m, the concentration of Mn and Mo decreased from a weak level of change to a strong one when approaching the roof of the sill. In sediments located above the sill with a thickness of 9.73 m, closer to its roof, the concentration of Mn and P decreased. In these sediments, the quantity of microelements, the content of which has changed, has become greater than in the sediments located above the 6.73 m thick sill. In sediments located between the 4 m thick pillow basalts and the 11.97 m thick massive basalt, a decrease in the concentration of Mo, Cd, and Sb occurred at the level of average intensity of change. Sills of different thicknesses from Hole 474/474A had a limited effect on the mineral and chemical composition of the enclosing sediments, in contrast to the significant influence of hot sills from Holes 478 and 481/481A (Guaymas Depression) on the composition of sediments.
Okeanologiâ. 2025;65(4):654-672
654-672
Geological structure of marine sediments around the Bennett Island according to the very high resolution seismic data
Abstract
Bennett Island, one of the least explored islands in the Eastern Arctic, is located in the northern part of the Novosibirsk Archipelago between the Laptev and East Siberian Seas and belongs to the Delong Island group. The article presents some of processing and interpretation results of very high-resolution seismic data obtained on the 78th cruise of the R/V Akademik Mstislav Keldysh in 2019. The analysis of seismic sections made it possible to trace the boundary of disconformity between ancient bedrock and young unconsolidated sediments over the entire research area. A relatively deep paleovalley of glacial origin has been discovered, located in the presumed continuation of the valley known in the southern part of the island. Accumulations of shallow gas in sediments were found to the southeast of the island. In the seismic section to the northwest of the island, a tectonically fragmented section of bedrock is observed, which may be associated with the formation of vapor-gas plumes observed on satellite images.
Okeanologiâ. 2025;65(4):673-680
673-680
The formation of the modern structure of the american-antarctic ridge
Abstract
The American-Antarctic Ridge is located between Bouvet Triple Junction and South Sandwich subduction zone. It is dissected by well pronounced transform faults. The common length of transform faults exceeds the common length of spreading segments. This structure was developed as a result of extension direction change during the subduction zone reshaping ca. 20 My. Basing on physical modelling we have reconstructed the conditions and the structural transformations during formation of the modern structural pattern of the American-Antarctic Ridge. In the experiment, oblique spreading segments through local ridge axis jumps became orthogonal. In that time, transverse discontinuities increased their length owing to reduction of oblique spreading segments and merging of several pre-existing transverse discontinuities. Perhaps, similar transformations could be observed during the modern structure formation of the American-Antarctic Ridge. In the western part, oblique to suborthogonal spreading segment transition has finished, while in the eastern part, structural pattern preserves as oblique as suborthogonal spreading segments. This situation may be determined by the influence of Shona and Bouvet mantle plume thermal anomalies. Thus, at the moment in the eastern part spreading and transform structures continue reshaping, and the structural pattern of the western part is stable.
Okeanologiâ. 2025;65(4):681-693
681-693
Structure of the mid-pacific sea mountains on geomorphological and cosmogeological data
Abstract
The use of morphostructural analysis and cosmogeological decoding methods by the working with relief digital models (3D) which were created within the Google Earth Pro program framework on the global bathymetric databases and maps (GEBCO_2014, GEBCO_2022 Grid) foundation made it possible to obtain fundamentally new information about qualitative and quantitative characteristics of the Mid-Pacific Seamounts and ocean floor adjacent areas structural elements. It was been established that the under consideration mountains are represented compound complexes of ring and linear groupings of abradated paleovolcanic constructions and other focal structures that form relict magmatic swells and underwater mountain ridges, respectively. Parameters, morphological features and basic regularities of focal structures of different sizes and depths laying location were detected, the network of fracture zones and block morphostructures of the region were briefly characterized. The main factors and mechanisms of mountain formation are associated with mantle diapirism phenomena and scale basaltoid volcanism, which have realized in pulsating regime throughout the Cretaceous period.
Okeanologiâ. 2025;65(4):694-709
694-709
Structure of the Crimean shelf based on seismoacoustic profiling of the sedimentary thickness
Abstract
The article presents the results of seismoacoustic studies of the Crimean shelf, carried out in 2018–2023 by the staff of the P.P. Shirshov Institute of Oceanology of the Russian Academy of Sciences. Based on the results of seismostratigraphic analysis, seven seismic complexes were identified in the sedimentary cover. Transgressive and regressive cycles in the Pleistocene–Holocene time and associated abrasion-accumulative processes were identified. Traces of buried river paleovalleys and their continuation in the form of submarine canyons on the slope and in the abyssal basin were discovered. The main patterns of lithofacies change in the Upper Pleistocene–Holocene deposits are associated with the latest block movements. Manifestations of degassing confined to the area of increased seismicity were noted.
Okeanologiâ. 2025;65(4):710-724
710-724
Информация
Multidisciplinary Research of the Nature of the Arctic Seas: Results of the Expeditions on the R/V “Dalnie Zelentsy” in 2024
Abstract
During the expeditionary work on the research vessel Dalniye Zelentsy in 2024, multidisciplinary oceanographic studies of the Arctic nature were carried out in the waters of the Barents, Kara, Greenland seas and the Arctic Ocean. Work was carried out to assess the current state and analyze changes occurring in the structure of pelagic, benthic, and ichthyofauna communities under the influence of climatic and anthropogenic factors. Qualitatively new information was obtained on the functioning of marine Arctic ecosystems in polar night conditions.
Okeanologiâ. 2025;65(4):725-727
725-727
GEOPHYSICAL MAPPING OF THE JAPAN SEA FOR ESTIMATION OF LATE NEOGENE TECTONIC ACTIVATION IN THE 87TH CRUISE OF THE R/V “PROFESSOR GAGARINSKIY”
Abstract
During the 87th cruise of the RV “Professor Gagarinskiy” geophysical studies within the shelf, slope, Japan Basin, Kita-Yamato Bank in the Japan Sea were conducted. New data on the structure of the sea bottom, sedimentary cover and features of the magnetic field were received.
Okeanologiâ. 2025;65(4):728-730
728-730