Filter-based differential hygroscopicity analyzer of aerosol particles

We describe a new differential analyzer implementing a technique for studying the hygroscopic properties of filter-precipitated aerosol particles based on a katharometric measurement of the amount of water vapor absorbed by an aerosol sample. The instrument has been tested on particles of sodium chloride and ammonium sulphate. A comparison of our data with the results of analogous measurements described in literature shows that the suggested technique has several important advantages, i.e., (1) higher sensitivity, which allows the measurement of particles of no more than 0.1 mg in mass; (2) a wide range of relative humidity variations (up to 99% at an accuracy of 0.06% RH at the upper-range value); (3) the absence of intermediate measurement steps connected with the need to account for water absorption by elements of a measurement system; and (4) the absence of restrictions to the size and shape of particles studied. In addition, the measurement technique rules out the possibility of errors caused by the kinetic effects of mass transport in the aerosol-water vapor system.     

Specific features of the 2010 summer heat formation in the European territory of Russia in the context of general climate changes and climate anomalies

Specific features of the extreme summer heat of 2010 in the European part of Russia are analyzed against the background of global and regional climate changes taking into account antropogenic influences and natural anomalies related, in particular, to the El Niño/La Niña phenomena. The tendencies of the characteristics of the activity of blocking anticyclones (blockings) responsible for the formation of drought regimes and the increase in the fire hazard at midlatitudes are estimated in connection with climate changes.     

Arctic sea ice long-term dynamics according to the satellite microwave data

The main results of processing the long-term satellite data in different spectral ranges and with different spatial resolutions used to map Arctic sea ice parameters are presented. The advantages of the methods developed in order to estimate these parameters on the basis of microwave sensor measurements are indicated. The specific features of the long-term dynamics of the main sea ice geophysical parameters (the sea ice area and distribution during the summer minimum, ice age structure and thickness, multiyear ice concentration, times of ice melt and freeze onset, etc.) are presented. The effect of changes in sheet ice on the status of large Arctic mammals is estimated.     

Stratified unbounded flow past of obstacles

We studied the surface perturbations of a two-layer ideal fluid induced by a flow past a submerged obstacle (simulated by a point dipole) in the vicinity of the density-jump layer. It is shown that the formation of two different types of surface waves is possible behind the flowed past obstacle in the real conditions of the open sea. The comparison of the amplitudes of the surface perturbations induced by the obstacle located above and below the density jump revealed their significant differences, which seems to be important for the use of this effect in practical problems.     

Relationship between the anomalies of temperature and air pressure over the ocean

This paper considers the relationship between multi-year air temperature and pressure fluctuations over the ocean, based on an approximate solution of the problem on the determination of large-scale seawater temperature anomalies from the conditions predominating at the sea surface. The dependence derived is numerically analysed using observations made in the North Atlantic. It is shown that the variability of annual mean air temperature anomalies is largely controlled by the air pressure field which has taken place during the preceding long-term period. The dependence derived may be applied to generate long-term forecasts of the ocean's hydrometeorological regime.Translated by Vladimir A. Puchkin.     

Four-dimensional analysis of the variability of hydrophysical fields in the tropical atlantic and on the shelf of guinea

The problem of monitoring of the mesoscale variability of hydrophysical fields in the shelf zone is considered. The usefulness of the data available in regional information centres is discussed. The possibility of monitoring the dynamics of the oceanic fields in the tropical Atlantic encompassing separate observation sites is demonstrated using the oceanographic databank of the scientific research centre (CERESCOR) in Conakry-Rogbane as an example. The results of assimilation of the hydrophysical survey data derived on the shelf in a telescopic model of the region are given.Translated by Mikhail M. Trufanov.     

Large-scale vertical hydroacoustic structure of the North Atlantic and its seasonal variability

A classification based on the number and types of large-scale acoustic waveguides is proposed for the mean seasonal profiles of sound speed propagation. A scheme for North Atlantic zoning, using typical curves of the sound speed vertical distribution, is given. The channel axis's position is shown not to depend on the water mass haline properties, being controlled by the temperature field vertical stratification.Translated by Vladimir A. Puchkin.