Influence of Tropical Cyclones of the South China Sea on the Variability of the Vietnamese Coastal Current Structure

The state of the natural environment of the marginal seas of the Northwest Pacific is largely controlled by the interaction of the atmospheric and hydrophysical processes. Tropical cyclones (typhoons), originating in the tropical zone of the Northwest Pacific and over the South China Sea basin, occupy a special place among atmospheric processes. The main destructive impact of typhoons falls on Southeast Asia. However, a significant number of are moving to the Russian Far East. The region of the South China Sea plays a significant role in the formation of tropical cyclones. This determines the importance of studying hydrometeorological processes not only in the Far East, but also in the South China Sea, and the need for cooperation between Vietnamese and Russian scientists. The main hydrodynamic structure of the western South China Sea is the Vietnamese Coastal Current (Western Boundary current), which depends not only on the seasonal monsoons but also on typhoons. The paper presents the results of joint Russian–Vietnamese studies of the dependence of the vertical structure of the Vietnamese Coastal Current on the Pacific tropical cyclones that form in the South China Sea. The study is done with numerical modeling. The period from April to June 1999 was used for modeling, provided with the necessary field data. The simulation results showed that, in general, the structure of water masses depends on the trajectories of tropical cyclones. In all cases considered, the Vietnamese Coastal Current is not a single flow, but represents a zone of eddy structures of different directions. An exception is the only situation in the condition of a tropical cyclone in the central region of the South China Sea when this current acquired the form of a single continuous flow directed from north to south only in the 200-m layer. The general patterns of changes in the dynamic structure of the Vietnamese Coastal Current for all the considered tropical cyclone trajectories include the following: areas with water transport in the northern direction prevail on the surface, while the rest of the water mass continues to flow generally in the southern direction. This transport of surface waters may be due to the influence of the emerging summer monsoon, and the rest of the water mass, which is less exposed to the still weak atmospheric processes of the monsoon type, continues to flow in the winter regime.

     

Search of ultra high energy cosmic rays’ sources. FRI-radiogalaxy Centaurus A

The propagation of ultra high energy cosmic rays in Galactic and extragalactic magnetic fields is investigated in the present paper. The motion of charged particles of different energies and chemical composition is simulated using different Galactic magnetic field models. Positions for the real sources of events registered at the Auger observatory are calculated taking into account the influence of both Galactic and extragalactic turbulent fields. The possibility of their correlation with the Centaurus A radio galaxy is analyzed.     

Estimation of the Incorporation of Impurity K and Na Ions in the CaSiO3 and MgSiO3 Crystal Structures at Pressures of 18–25 GPa

Doklady Earth Sciences - Based on atomistic modeling data, various schemes of the isomorphic incorporation of K+ and Na+ ions into the crystal structures of CaSiO3 and MgSiO3 in the pressure range...     

Kara-Bogaz-Gol Bay: Physical and Chemical Evolution

Kara-Bogaz-Gol Bay is a large (around 18,000 km²) and shallow (few meters deep) lagoon located east of the Caspian Sea. Its water surface was several meters to several dozens cm lower than in the Caspian Sea, so water flows from the Caspian Sea through a narrow strait into the bay, where it evaporates. Kara-Bogaz-Gol Bay is one of the saltiest bodies of water in the world; its water salinity amounts to 270–300 g/l. Different kinds of salts available in this natural evaporative basin has been used commercially since at least the 1920s. In March 1980, in order to decelerate a continuous fall of the Caspian Sea level, which in 1977 was the lowest over the last 400 years (?29 m), the Kara-Bogaz-Gol Strait was dammed. In response to this human intervention, the bay had already dried up completely by November 1983. In 1992, the dam was destroyed, and Kara-Bogaz-Gol Bay had been filling up with the Caspian Sea water at a rate of about 1.7 m/year up to 1996 as observed by the TOPEX/Poseidon satellite altimetry mission. Since then, Kara-Bogaz-Gol Bay level evolution with characteristic seasonal and interannual oscillations has been similar to that of the Caspian Sea. Physical and chemical evolution of the bay in the twentieth and twenty-first centuries is traced in detail in the paper.     

中国东北新生代火山活动与地热资源

本文论述了中国东北新生代火山活动的时—空分布规律和温泉及热流高值区的空间分布特征,揭示了热流高值区和温泉分布区与新生代火山活动、裂谷运动和断裂活动的内在联系,特别强调了活动断裂对温泉和地热高异常区形成的控制作用。提出新生代火山活动区、裂谷盆地、断裂强烈活动区和大地震发生区,以及活化的古板块缝合带等地区,是最有利的地热资源勘探靶区。     

CENOZOIC VOLCANISM AND GEOTHERMAL RESOURCES IN NORTHEAST CHINA

1 INTRODUCTION Northeast China is located in the eastern marginal part of Eurasian plate. There are about 700 Cenozoic volcanoes and about 50 000km2 volcanic rocks in Northeast China. The Cenozoic volcanism is related to the Pacific plate subducting, back-arc spreading and corresponding marginal continental rifting. About 700 Cenozoic volcanoes in Northeast China are concentrated at some places, so Shuangliao, Keluo, Wudalianchi, Yitong, Shulan, Shangzhi, Longgang, Jingbo Lake, …     

On the problem of the formation of the Greenland sea convective gyre

The transformation of the interfaces of a rotating three-layer fluid is described through a simple hydrodynamic model using the shallow-water approximation. Using the Greenland sea gyre as an example, it is shown that a cyclonic circulation results in the oncoming deflection of the upper and lower layers, which favours the development of deep convection.Translated by Mikhail M. Trufanov.