Home – Home – Jornals – Atmospheric and Oceanic Optics 2014 number 9

New parameterization of the effective dipole moment matrix elements for asymmetric top molecules is suggested. It is based on the introduction of the Herman-Wallis type factors for the matrix elements. The advantage of this new parameterization consists in the utilization of the matrix element parameters which describe explicitly the dependence of the principal matrix element parameter on the rotational quantum numbers J and K. The application of this approach to the open-shell NO₂ molecule is discussed.

We present a classification and a frequency of the new particle formation (NPF) bursts observed in the atmosphere over boreal zone of West Siberia, which are based on the data of continuous in situ measurements of the aerosol size distribution carried out in a wide range at two stations for atmospheric composition monitoring IAO SB RAS owned. Analysis of the data obtained from 2010 to 2013 showed that NPF bursts happen during 20-30% days analyzed. The most part of the NPF events are observed in spring (from March to May), and a secondary maximum is typical for September. Seasonal pattern and annual mean NPF frequency observed in West Siberia are similar to ones observed in boreal forests at background stations of Scandinavia, at that our data are in close agreement with long-term observations of SMEAR II station (Hyytiälä).

Variability is considered of medium size fraction of ground aerosol particles with radii of 0.3–0.6 mm during the winter-spring change in the experiments carried out at aerosol station LOA IAO SB RAS in 2009–2013. The time variations of aerosol extinction coefficient for the spectral range 0.50–3.9 mm obtained along a surface path and a function of particle size distribution in the range 0.2–5.0 mm measured using a photoelectric counter PKGTA at one end of the path are analyzed. Connection of the variations of medium size particle concentrations and submicron aerosol condensation activity are studied. The experimental spectral attenuation coefficients are compared with calculated by the Mie theory for the approximate size distributions.

The function of mutual coherence of the field and the mean intensity of partially coherent pulsed optical radiation scattered by an atmospheric layer have been calculated. It is shown that as the pulse duration decreases, the spatial coherence of backscattered radiation improves in comparison with the coherence of scattered continuous-wave (cw) radiation. In contrast to cw radiation, which is scattered uniformly in the backward direction, the backscattering of pulsed radiation becomes non-isotropic for shorter pulses, and for sufficiently short pulses, the backscattered radiation is localized near the strictly backward direction in the zone with transverse dimensions comparable with the initial size of the sensing beam.

Variability of concentration of chemical elements in snow cover of the typical regions of the central part of the Western Siberia is studied. Decrease of variability and concentration of chemical elements has been found in the south-north direction. This tendency is observed not only for “soil-erosion” elements (Сa, Fe, Al, Sr), but also for those considered “technogeneous” — V, Cо, Pb, Zn, Cd. Northward decrease of concentrations is the most pronounced between the steppe and southern taiga zones.

By results of seasonal measurements of spectral transparency and concentration of chlorophyll a dependence is found in water of different-type lakes of Altai Krai during 2011–2013 between these indicators, presented in the form of approximating curve, satisfying the Bouguer law. The analysis of the obtained experimental data taking into account disperse structure of particles (cages) of seaweed phytoplankton is carried out.

The properties of the light scattering on a column-like bullet and droxtal of cirrus clouds oriented preferably in a horizontal plane have been calculated in the geometrical optics approximation. The shape parameters of crystals F and the flutter are assumed to be equal to 10 and 5 degrees respectively. The Parry and 3D orientations of crystals in space have been analyzed. Based on the results, the tabular information of the distribution of the scattered light among the brightest halo has been represented. The results have been compared with scattering on the hexagonal column.

The paper describes a technique for automatic identification of internal gravity (buoyancy) waves in the atmospheric boundary layer from results of remote acoustic sounding. The technique is based on the analysis of sodar echograms with the use of artificial intelligence and digital image processing methods. The technique is intended for identification of a certain type of manifestation of internal gravity waves in sodar echograms and tested with a great number of experimental data. The periods and amplitudes of internal gravity waves of this type are estimated from a test sample of 72 sodar echograms.

The series of ground-based high resolution Fourier-transform measurements of atmospheric transmittance in near infrared region (4000–10000 cm^–1) recorded at the Ural Atmospheric Station in 2012–2013 was processed in order to retrieve relative concentrations of CO₂ and CH₄ in atmospheric column. Retrieved values of methane concentration do not show a noticable seasonal cycle, while retrieved CO₂ concentrations show clear seasonal variations with high amplitude, which are also observed in GOSAT measurements over Ural region. The estimated amplitude of CO₂ seasonal variations is 14–15 ppm. Intercomparison between ground-based and GOSAT measurements of CO₂ shows a good agreement, while satellite values are overestimated by approximately 3 ppm. There is no noticable correlation between CH₄ values, which one can explain by presence of local methane sources in the area of GOSAT observations.

The development of the estimation method of air masses movement in the lower stratosphere using ozone as atmospheric tracer is discussed. Two fields of the total ozone for a current day and previous day are compared using correlation extreme algorithm. The result of the procedure is estimation of mutual shift of the fields and of zonal and meridian air movements per day. Zonal movements of air mass at 1997–2004 were investigated for the Northern and Southern hemispheres. The proximity of the average values of the lower stratosphere zonal wind and the troposphere zonal wind (with respect to the Earth surface) was found out. E.N. Blinova’s zonal movement index was estimated for mid-latitudes of both hemispheres. We found that the field of total ozone at mid-latitudes of the Southern hemisphere rotates 1.8 times faster than the field of the Northern hemisphere. From July to October, 2003 there was anomalous decrease of the index; it was connected apparently with increasing solar activity. It was found that there is a close correlation between the Earth orbital speed and the angular velocity of the lower stratosphere at mid-latitudes of both hemispheres.

Thermodynamical modeling of the carbon, methane, nitrongen oxide, and chlorofluorcarbon emissions have been carried out near the Earth's surface up to a height of 500 m at an average temperature of 15°С and in the troposphere up to a height of 2 km at a temperature of 3°С (at pressures of 1013.25 and 790 gPa). It has been ascertained that doubling of the CO₂ concentration in the surface air layer can cause an increase in the surface temperature on the planet up to 18.15°С by 2100, to 19.43°C with additional contributions of CH₄, to 20.08°С with accounting for N₂O, and to 23.35°С with accounting for all gases including chlorofluorocarbons and water vapor; in the lower troposphere, the temperature can increase to 4.64°C with an increase in CO₂, to 5.83°С with an additional contribution of CH₄, to 6.51°С with accounting for N₂O, and to 7.61°С with accounting for all gases, including chlorofluorocarbons water vapor.

A technique is proposed for estimation of the structure characteristics of refractive index of air from data of a coherent Doppler wind lidar. The proposed technique is tested in atmospheric experiments. Time profiles of the structure characteristics of refractive index in the atmospheric surface layer are obtained and compared with the time profiles of the dissipation rate of the kinetic energy of turbulence obtained from the same lidar data. It is shown in this way that coherent lidars can be used for investigation of not only wind turbulence, but also temperature turbulence.

The results of measurements of the total cloudiness using two ground instrumental methods are presented. The first method is based on an analysis of the blue sky and the second method uses a two-dimensional wavelet analysis. According to studies, measurements with the both methods fit together well, but differ greatly from traditional visual data, especially in the presence of cirrus clouds in the sky. Both methods use simple algorithms and low-cost recording devices. This allows applying them for remote measurements of total cloudiness automatically without human presence.