Home – Home – Jornals – Advanced Search

The paper presents the results of calculations of the broadening and shifts of absorption lines of CO confined in nanoporous media. The collisions with walls and absorbed rotational and non-rotataional CO molecules are taken into account. The comparison with the existing experimental data is discussed.

Numerical simulation is carried out in order to evaluate possibilities of crosswind velocity determination along an observation path between distant object and observer. The proposed simulation method is based on the analysis of atmospheric distortions in the object images. The influence of limited atmospheric areas on the object image distortion and possibilities of the drift velocity retrieval in these areas are investigated. A new method for filtration of turbulent distortions by their characteristic sizes is suggested with the aim to determine the wind velocity at different segments of the observation path. It is demonstrated that the evaluation method allows one to determine crosswind velocity with high accuracy when it is applied to a thin layer of atmospheric inhomogeneities.

On the basis of simulation of water molecule interaction in small clusters in the presence of ions the binding energy of molecules and supersaturation of vapor being in balance with small droplets is calculated. Supersaturation thresholds are found. It is shown that negatively charged droplets have a lower threshold than positively charged ones. In the calculations, the four-point potential for water molecules is used.

In the present work, results of experimental investigations into the influence of turbid media (fog, smoke) on the quality of image of objects observed through them using active pulsed OES operating in the modes with constantly open receiver and controllable receiver (in the mode of selection of backscattered noise signal) are considered. It is experimentally confirmed that in the active pulsed OES with selection of backscattered noise signal, the quality of images of objects screened by turbid media can be almost 10 times higher than in the case of their operation with constantly open receiver. The image quality of objects in systems of vision with controllable reception is influenced not only by the optical length of the observation path but also by such characteristics as the average sizes of particles and their scattering and absorbing properties.

The results are presented of experimental studies of spatial characteristics of postfilamentation light channels in air formed by femtosecond pulses of Ti:Sapphire laser with different energy for focused and collimated beams. It was found that for a focused beam in the far zone from the filamentation region, the angular divergence of channels is dozens of times lower than the angular divergence of the beam as a whole. The angular divergence of the channels is first significantly reduced with an increase of the pulse energy, then goes into a saturation mode. For collimated beams, at a fixed distance from the source, an increase in the pulse energy also leads to stabilization of the transverse dimension of the channel

From long-term observations of the upper atmosphere emission in Eastern Siberia, we studied features of seasonal [OI] 557.7 nm emission variations. We found qualitative similarity with seasonal 557.7 nm emission variations obtained from other mid-latitude stations in the Northern hemisphere in previous decades. Among differences are less pronounced annual summer maximum and significantly lower values of 557.7 nm emission intensity in April and the next three months. We found significant correlation coefficients between the monthly averages of 557.7 nm emission intensity and F_10.7 solar radio flux index only for autumn and winter months. We discussed possible reasons and mechanisms of the observed 557.7 nm emission variations. We used observations from the Geophysical Observatory of Institute of Solar-Terrestrial Physics SB RAS (52° N, 103° E) for 1997-2016.

Field measurements methane and carbon dioxide fluxes have been conducted on two sites of Western Siberia in south and middle taiga on August 16-24, 2015. Static chamber method had been used. Two measurement sites were chose in Bakchar bog, Tomsk Region, for typical local ecosystems (from oligotrophic bog to enclosed forest and periodically flooded forest) and in waterlogged forest near Shapsha settlement, Khanty-Mansi Autonomous Region. Maximum methane fluxes have been measured from the overmoistening territory of burnt birch forest (median is 6.96; lower and upper quartiles are -3.12 and 9.95 mgС × m^-2 × h^-1, respectively). Minimum of these parameters (among the above objects) was measured in the periodic seasonal waterlogged forest (median, lower and upper quartiles are -0.08, -0.14 and -0.03 mgС × m^-2 × h^-1, respectively). These data may be used for estimation of regional methane fluxes from waterlogged and periodically flooded forests and for forecast of their influence on the total balance of greenhouse gases in the atmosphere.

Effects of the major sudden stratospheric warming event in January 2009 on the stratospheric circulation dynamics are analyzed. Irreversible splitting and successive destruction of the arctic circumpolar vortex on January 24, 2009, are shown to cause anomalously early alteration of the stratospheric circulation. The dynamics of vertical temperature profiles over the Ny-Ålesund and Alert stations reflecting distribution of warming from the middle stratosphere to the upper troposphere and the tropopause evolution has been analyzed. Here we consider the uncharacteristic trend in the total ozone content within the Arctic region preventing the restoration of the winter circulation pattern during the winter and spring time in 2009 after the sudden stratospheric warming.

It is shown how ground-based remote sensing can help us to improve the knowledge of atmospheric boundary layer and how mesoscale synoptic models can be used as a hindcasting tool. A technique is suggested for evaluation of the quality of boundary layer representation in the models using remote sensing data.