Home – Home – Jornals – Atmospheric and Oceanic Optics 2013 number 7

The procedure of the selection of halfwidths of absorption spectral lines measured in different works for intermolecular potential determination is proposed. The procedure is based on the analytical model for half-widths. Two examples connected with spectral lines of 2ν₁ + ν₂ + ν₃ vibrational band of H₂O molecule and ν₂ band of H₂S molecule broadened by helium pressure are discussed.

A technique for computer reconstruction of the pressure signal shape from the pulse microphone signal is offered. It is shown that the time of collisional relaxation of molecules from the excited state to the ground one can be measured on its basis with the use of a time-resolved photoacoustic spectrometer.

We present the observations results of aerosol disturbances in the stratosphere in the second half of 2011; the observations were performed at stations of CIS lidar network CIS-LiNet in Minsk (53.9°N; 27.60°E), Tomsk (56.5°N; 85.0°E), and Vladivostok (43.0°N; 131.9°E). Based on the lidar measurement data at the sensing wavelengths of 353, 355, and 532 nm, an increased aerosol content was observed in the lower stratosphere up to altitudes of 18 km from June–July and practically until the end of 2011. A well-defined and temporally stable aerosol layer was observed until October 2011 in the altitude range 13–17 km. An increased aerosol content in the lower stratosphere was observed until January 2012. The trajectory analysis of air mass transport in the stratosphere on the basis of NOAA HYSPLIT MODEL with the use of CALIPSO satellite data shows that the observed increased aerosol content was due to the transport of eruption products of Grimsvötn volcano (May 21, 2011, Iceland: 64.4°N; 17.3°W).

In the present paper, the potential capabilities of lidar measurements of the atmospheric density in the middle atmosphere are analyzed. Calculations are performed for a lidar with quite moderate specifications: transmitter comprising a solid Nd:YAG-laser with a wavelength of 532 nm, pulse energy of 0.8 J, and repetition frequency of 20 Hz; and receiving system comprising primary mirrors with radii of 0.3 and 0.5 m, field-of-view angles of 0.1 and 1 mrad, and spectral widths of the filter of 0.5, 1, and 10 nm. The signal acquisition time is 10 min for spatial resolution of 1 km. Three sensing options are analyzed: from the ground level, from an aircraft (at 10-km flight altitude), and from an ISS with orbit altitude of 414 km.

Algorithms for reconstruction of the Earth’s surface reflection coefficient from the data of satellite measurements are suggested. They allow the main components of radiation, forming an Earth’s surface image, to be taken into account with different degrees of accuracy. The algorithms involve a solution of the radiative transfer equation with the use of the linear system theory, Monte Carlo method, approximation formulas, and criterion of image isoplanarity. The algorithms are validated based on numerical experiments and comparisons with results of calculations by other authors.

The results of numerical simulation of aerosol radiative forcing for three regions of the Ocean are presented: the coastal area of Antarctica, the Sea of Japan, and the Sea of Darkness. In the simulation of aerosol radiative forcing in these regions the results of ship measurements of aerosol optical depth and water vapor content are used. Data on the single scattering albedo and asymmetry factor are represented by the model (coastal Antarctica – model OPAC) and long-term observations at AERONET photometric stations (Sea of Japan – Noto site and the Sea of Darkness – Cape Verde site). Calculations showed that cooling effect of aerosol over the Japan Sea/Sea of Darkness on the borders of atmosphere increases by about an order of magnitude as compared to the clear atmosphere near Antarctica. In this case, the daily averaged values of the aerosol radiative forcing change as follows: at the level of the underlying surface from –2.3 (Antarctica) to –30.3/–32.6 W/m² (Japan Sea/Sea of Darkness), at the top of the atmosphere from –1.9 to –16.1/–18 W/m². The estimates obtained are in good agreement with the results of other authors.

The low clouds conditions over the territory of the Siberian region are researched, using the 47-year (1966-2012) observation data of 25 meteorological stations. The spatial distribution of the seasonal average values of the amount of low-level clouds and their frequency according to five gradations (amount of clouds: 0, 1-3, 4-6, 7-9, and 10), as well as the cloud base heights and its standard deviations was analysed for four seasons (winter, spring, summer, autumn).

The results of the analysis of climatic changes of the amount of low clouds over the territory of Siberia for the last 47 years (1966-2012) are presented according to the data of ground-based meteorological observations of 25 stations with annual and seasonal averaging. It has been found that the significant long-term fluctuations of the lower clouds are typical for the concerned period (relative to the standard of the 1966-1975 or 1976-2005). The amount of low clouds increased everywhere at the end of the XX century and at the beginning of the XXI (from 1976 to 2005), when global warming was observed over the territory of the Northern hemisphere. Over the period of the started cooling (2006-2012) a significant decrease of the amount of low clouds has been observed over the Western Siberia, and the marked weakening of its growth has been observed over the Eastern Siberia.

The description of an automated multi-wavelength path photometer, which serves for the convenience of transparency measurements of the atmospheric surface layer (the total length of optical path is 1000 meters) at 13 discrete points of the wavelength range 0.45÷4.6 mm. The fundamental difference of the photometer from the previous version is that all receiving modules with their interference filters and optimally matched optical radiation detectors are rigidly fixed in a circle on the fixed panel. At the center of this panel on the axis of a step motor, a small flat mirror is fastened, directing the incoming radiation to the appropriate collecting module according to the program.

The simple and effective method (technique) of the leakage test of the respiratory system using medical ventilation apparatus and laser photoacoustic leak detector “LaserGasTest” was suggested. The technique was tested in model experiments and experiments on animals. Sulfur hexafluoride is inert and biologically harmless gas and its concentration in medical ventilation apparatus does not exceed 5000 mg/m³ (0.077%). The proposed technique provides precise location and size of leakage.

In this paper the dependence of snow water dielectric characteristics on pollutants accumulated in snow cover for all the period of snow accumulation is defined. The results of calculation of dielectric characteristics considering the accumulated pollutants are presented. A technique that characterizes the impacts of accumulates pollutants in snow cover on the dielectric properties of snow water using regression analysis is suggested.

The dependence of energy characteristics of a CuBr laser of an average active volume with and without HBr addition on the rate of the current rise is under study. The variation of the energy characteristics is conditioned by connecting an additional inductance in the discharge circuit. It is shown that at the increase of the inductance up to 4 mH, the average lasing power of the CuBr laser decreases tenfold. Under similar conditions, the average generation power of the CuBr laser with HBr addition decreases by less than two orders of magnitude. The portion of yellow line generation also changes by a less degree. Thus, the presence of the electronegative addition to the CuBr laser active medium decreases requirements to the pulse power supply.

The interaction of the Tunguska cosmic body and the Chelyabinsk object (Chebarkul meteorite) with the atmosphere has many common characteristics. The water vapor, caused by fragmentation of objects before their penetration in the atmosphere, was registered at the altitude of the mesopause in both events. The rainbow bands, which were seen in the tail of the Tunguska body, are connected with refraction and reflection of sunny rays in horizontal (parhelic) ring. A forming of explosion rejections of the substance from the Chelyabinsk object with a speed of ~ 1 km/s (which is typical for comets) and a fragmentation of the object outside the atmosphere lead to conclusion about the comet nature of the Chelyabinsk object.