A simple theoretical interpretation of the cloud system in a dying cyclone from the aspect of the boucher-newcomb model

Резюме С помощью принятия простых кинематических предположений и на основании ω—уравнения выла определена конфигурация полос облаков в полностью окклюдированном циклоне без фронтов. Облачная система определяется полем скрытой теплоты, выделяемой в процессах конденсации. Полосы облаков теоретически представляют собой в основном листы синусоидальной спирали.

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Address: Boční II, Praha 4-Spořilov.     

Seismic modelling,development and outlook

Резюме Описаны этапы развития сейсмического моделирования, взаимоотношения между сейсмическим моделированием, теоретическими разработками и полевыми наблюдениями и формулированы перспективные задачи сейсмического моделирования.

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Address: B. Gruzinskaja 10, Moskva G-242, USSR.     

Electrochemical strengthening of clayey sandy soils

Most previous studies and applications of electrochemical stabilization of soils through electroosmosis have been made on clayey soils. The object of this investigation was to find out if relatively small amounts of clay (1.5%–3.5%, by weight) present in a sandy soil would be enough for stabilization and strengthening to be possible. The results indicate increases of cohesion of the order of 100–200 lb./sq.ft. X-ray analyses of treated soils indicate that sheet structures of clays are reduced and silicates destroyed upon treatment by electroosmosis. Newly-formed minerals also cement the soil. These neoformations include gibbsite, limonite, calcite, hydrohematite, hydrogoethite (hydrolepidocrocite), hisingerite, allophane, allophanoid, gypsum, hematite, magnetite, nontronite, trona and natron (Na₂ CO₃, 10H₂O). The process seems to be irreversible.     

Climatic satellite monitoring of the external heat balance of the oceans and Black Sea

The long-wave outgoing radiation, effective cloudiness equal to the product of the total cloud amount by their optical density, and the sea-surface temperature determined from the satellites are used to determine the annual course of the components of external heat balance on the sea surface whose climatic anomalies, parallel with the meridional heat and water transfer in the ocean-atmosphere system, specify the intraannual and interannual large-scale variations of weather in different regions of the Earth. The development of these studies is connected with the progress of satellite hydrophysics because the data obtained from the space become sufficiently exact, regular, and global. The increase in the existing data array on the external heat balance of the oceans from ∼15–20 to 100 yr and more would promote the solution of the problem of oscillations of Earth's climate. We present examples of coordinated numerical analysis of the heat balance of the upper (0–100 m ) layer of the Black Sea performed on the basis of the shipborne and satellite data. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 59–75, November–December, 2007.     

Numerical modelling of the seasonal variability of hydrophysical fields in the Black Sea

The results of research into the seasonal variability of hydrothermodynamic characteristics of the Black Sea are presented. These have been obtained using field data on the fields of temperature, salinity, and wind, and by mathematical modelling. The seasonal variability of the current and heat content fields and of the cold intermediate layer and other hydrophysical characteristics is discussed.Translated by Mikhail M. Trufanov.     

Validation of a finite difference method for the simulation of vortex-induced vibrations on a circular cylinder

The Karman Vortex Street generated by a circular cylinder is investigated by the numerical solution of the compressible Navier–Stokes equations in the incompressible Mach number range (Mach<0.3) using the Beam and Warming implicit scheme. The agreement with the fully incompressible projection method (Chorin, 1968) is fairly good while convergence time is very much better. The investigation suggests that the compressible Navier–Stokes equations may be used as an efficient alternative to study incompressible flows as well. Mach numbers just below 0.3 are enough to simulate incompressible flow behavior and at the same time do not cause numerical ill-conditioning in the solution. In addition, some relevant features of the vortices generated and carried by the wake of the cylinder could be fairly well captured.     

Weakly non-linear free oscillations in a basin of variable depth

Weakly non-linear free oscillations in a basin of variable depth filled with non-viscous fluid are investigated in terms of the long waves theory using the perturbation technique. Solutions to the initial two approximations for the horizontal velocity component and free surface departure are numerically derived. An attempt is made to determine the area of applicability of the linear theory by applying a parabolic bottom profile to the basin.Translated by V. Puchkin.     

Spatial and temporal variability of the ratios between the nitrate and phosphate concentrations in the Sea of Okhotsk

The relation between the nitrate and phosphate concentrations in the Sea of Okhotsk and the bordering waters of the Pacific Ocean were studied. The surveys were carried out in the autumn, spring, and summer of 2001–2002. For the deepwater part of the sea, the relation [NO^? ₃] = ((14.88 ± 0.07) × [PO^3? ₄] ? 5.46 ± 0.17) was found. The coefficients in the equation given are statistically different from those in the similar equation for the Pacific waters: [NO^? ₃] = (16.05 ± 0.15) × [PO^3? ₄]-(7.23 ± 0.36). In the northern part of the sea; on the shelf; in the slope area; and, especially, in the deep waters of the TINRO Depression, the linear dependence between the phosphate and nitrate concentrations was distorted. This feature was described in terms of nitrate deficiency. The maximum values of this deficiency were found in the near-bottom waters. The principal processes that might cause the nitrate deficiency were considered: the difference in the oxidation rates of the nitrogen and phosphorus organic compounds, the matter transfer between the continent and the sea, the different efficiency of the biogenic burial of nitrogen and phosphorus in the bottom sediments, and the denitrification in the upper layer of the bottom sediments. It was shown that the most probable cause of the nitrate deficiency was the denitrification. The loss of inorganic nitrogen owing to the supply of the waters of the Sea of Okhotsk to the Pacific Ocean was estimated as ～2.5 × 10¹¹ mol N/year.     

Rock magnetic records of the sediments of the eastern Arabian Sea: Evidence for late Quaternary climatic change

Rock-magnetic measurements along with grain size, acid-insoluble residue (AIR), organic carbon (OC), CaCO₃ and δ¹⁸O of the planktonic foraminifers of the sediments were determined for 15 gravity cores recovered from the western continental margin of India. Magnetic susceptibility (MS) values in the surficial sediments reflect the land-derived input and, in general, are the highest in terrigenous sediment-dominated sections of the cores off Saurashtra–Ratnagiri, followed by the sediments off Indus–Gulf of Kachchh and then Mangalore–Cape Comorin.

The down-core variations in mineral magnetic parameters reveal that the glacial sediments off the Indus are characterized by low MS values/S-ratios associated with high AIR-content, low OC/CaCO₃ contents and relatively high δ¹⁸O values, while those off SW India are characterized by low MS values/high S-ratio% associated with low AIR content, and relatively high OC, CaCO₃ and δ¹⁸O values. Conversely, the Early Holocene sediments of all cores are characterized by high MS values/S-ratio% associated with high AIR content, low OC, CaCO₃ contents and gradually decreased δ¹⁸O values. These results imply that during the Last Glacial Maximum (LGM), the cores off northwestern India received abundant continental supply leading to the predominance of eolian/fluvial sedimentation. In the SW region the influence of hinterland flux is less evident during this period, but convective mixing associated with the NE monsoon resulted in increased productivity. During the early Holocene intense SW monsoon conditions resulted in high precipitation on land, which in turn contributed increased AIR content/MS values in the continental margin sediments. A shallow water core off Kochi further suggests that the intense SW monsoon conditions prevailed until about 5 ka. The late Holocene organic-rich sediments of the SW margin of India were, however, subjected to early diagenesis at different intervals in the cores. Therefore, caution is needed when interpreting regional climatic change from down-core changes in sediment magnetic properties.