Mesoscale Variability of the Ocean in the Northern Part of the Weddell Sea

Oceanology - Results of a mesoscale survey in the Powell Basin in the northern part of the Weddell Sea are analyzed. The survey included 24 CTD casts (6 × 4) with an interval of six nautical...     

On the influence of the sea surface temperature on the carbon dioxide exchange with the atmosphere

The influence of the sea surface temperature (SST) on the carbon dioxide (CO₂) exchange with the atmosphere at different spatial and temporal scales, which has a multidirectional character, was studied. The initial data included the monthly averages of the CO₂ flux during the period of 1982–2011 at grid nodes of 4° by latitude and 5° by longitude, as well as the SST satellite data from January 1, 1982 to December 31, 2012 at the geographical grid nodes of 0.25° × 0.25°. Statistical models of estimation of the resulting global CO₂ flux were suggested on the basis of data on SST anomalies. It is demonstrated that the SST variations in the equatorial zone mostly control the interannual fluctuations of the resulting CO₂ flux in the ocean-atmosphere system.     

An experimental study of structures arising in convective roll flows of magma melts in peripheral chambers of volcanoes

The morphology and internal convective structure of continuous roll flows in magma melts were experimentally studied with regard to peripheral (shallow) magma chambers and downgoing circular gravity flows in conduits. We found properties of continuous convective mixing in a magma melt in a peripheral chamber due to convective roll flows. We investigated the mechanism that is responsible for cumulus generation at the bottom of a peripheral chamber when homogeneous and heterogeneous melts are emplaced. We conducted an experimental study of how the contact surface is formed at the cumulus-melt boundary. We made a qualitative study of the mechanism that affects the composition of magma melts over time in a peripheral and a mantle (deeper) chamber owing to crystallization, as well as the special mechanism that is responsible for cumulus generation in the peripheral chamber.     

Effect of Moisture Exchange in the Northern Atlantic on European Russia Moistening and Annual Volga Runoff

Water Resources - The interaction between hydrological cycle components in the ocean–atmosphere–land system was considered. Calculations were made with the use of various reanalysis...     

Variability of hydrophysical characteristics in the Gulf Stream

We consider the interannual variability of the intensity of the Gulf Stream and interannual fluctuations of seawater parameters in the Gulf Stream and in the Labrador Current during intense climate warming. We show that this intensity has increased during this period. The scales of fluctuations and their contribution to variance in the initial time series was determined from wavelet analysis of the Gulf Stream north wall. We noted a considerable decrease in water density of the main branch of the Gulf Stream, caused by the increase in temperature due to global climate warming, and an absence of trends in water density of the main branch of the Labrador Current.     

Specific structure of convection currents in the system layered intrusion–feeding conduit–parental magma chamber

The structure of convection currents was experimentally studied in the model system layered intrusion–feeding conduit–parental magma chamber. Persistent hydrodynamical and thermophysical interaction between interrelated melts of the parental magma and intrusive body occurs through the feeding conduit. Being associated, they control the structure of convection currents and mechanisms of heat and mass transfer in the intrusive, conduit, and magma chamber. The existence of two convection countercurrents in the conduit has experimentally been established: inner central lifting jet and outer annular downward current along the conduit walls. At the top of the conduit, the downward current has the lowest temperature and appears to be quite in equilibrium with the earlier precipitated crystals. Moving downward along the conduit wall, the annular descending current interacts with the lifting jet and, as a result, becomes hotter and undersaturated relative to the crystals that formed before. Thus, there is no possibility for heterogeneous crystallization to occur on the walls of conduit. The experimentally simulated mechanism of melt interaction in a whole natural system rules out the possibility of formation of a zone of immobile melt with stable steady-state temperature stratification anywhere in the chamber's volume.     

Variability of Evaporation and Precipitation over the Ocean from Satellite Data

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.     

Simulation of the probable maximum flood in the area of the Leningrad Nuclear Power Plant with account of wind waves

At the designing of nuclear power facilities at the coastal sites the risk of their flooding caused by the combinations of adverse hydrometeorological events should be assessed with the probability of exceedance to 0.01%. According to the IAEA recommendations, the combination of statistical and deterministic methods was used to calculate the flood level of such rare occurrence. The level of flooding caused by the storm surge and reiated wind waves were computed with the probability of 0.01% for the coastal part of the Koporye Bay of the Gulf of Finland in the area of the Leningrad Nuclear Power Plant 2 (LNPP 2) construction; the results are presented. The calculations are based on the CARDINAL and SWAN software and four nested numerical models (for the Baltic Sea, the eastern part of the Gulf of Finland, the Koporye Bay, and a part of the bay in the area of LNPP). The decrease in sea-surface drag coefficient at hurricane winds is taken into account.     

Genetic Diversity of Copepod Limnocalanus macrurus from Russian Arctic Seas

Oceanology - The diversity, phylogenetic relationships, and demographic history of glacial relict copepod Limnocalanus macrurus from estuaries of large Siberian Arctic rivers (the Ob, Khatanga,...     

An experimental study in the structure of convective flows of magma melts in a complete system: Mantle chamber-intermediate chamber-volcano

A continuous interrelationship of melts in intermediate and mantle chambers is found by experiment. The interrelationship occurs due to the presence of two melt counter currents within the supply channel (conduit) of the intermediate chamber. In the upper part of the intermediate chamber horizontal rolling flows are found to go from the center to the periphery and backward horizontal flows over the entire bottom of the intermediate chamber travel from the periphery to the center (the conduit), then become an annular descending flow. Due to thermal interaction with the central ascending flow, the annular descending flow heats and becomes undersaturated relative to precipitated crystals, thus excluding encrustation of the conduit walls. The mechanism of continuous interaction between the melts in the mantle and intermediate chambers provides a quasisteady-state of the system irrespective of volcanic activity. It is thought that horizontal layering in large basic intrusives forms similarly to the described process of development and accumulation of cumulus at the bottom of the intermediate chamber.