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We present the results of calculating the vibrational and rotational terms of the X²Π and B²Σ⁺ electronic states of the phosphorus oxide (PO) molecule. The absorption spectrum corresponding to the electronic transition B²Σ⁺ (v′ = 0) - X²Π (v″ = 0) has been calculated. The efficiency of laser excitation of PO molecules is estimated as a function of the spectral parameters of the radiation. It has been established that the excitation efficiency of the B²Σ⁺ (v′ = 0) - X²Π (v″ = 0) electronic transition of the PO molecule is approximately an order of magnitude lower than that of the A²Σ⁺ (v′ = 0) - X²Π (v″ = 0) transition. The result is of practical importance from the point of view of choosing the optimal scheme for laser excitation of the fluorescence of PO-fragments in the implementation of the method of remote detection of organophosphates.

The turbulence parameters obtained using lidar are compared with the parameters determined from the average values of velocity and temperature in the surface air layer. The results of observations of the structural constant of the refractive index C_n² obtained from the ratio of the turbulent lidar returns in the surface air layer when working along a slightly inclined sounding path are presented. A method for determining the rate of kinetic energy dissipation from lidar data has been tested.

In winters-springs 2010/2011 and 2019/2020, there were the strongest anomalies of ozone layer in the Arctic stratosphere in the total satellite era. They were due to extraordinarily strong and long-lived stratospheric polar vortices, entailing unprecedented chemical ozone destruction. The analysis of the TEMIS data indicates that the total ozone content (TOC) deviations from the multiyear (2003-2019 except 2011) average were from 37 to 44% in 2011 and from 45 to 55% in 2020 at Arctic observation stations; and from 27 to 36% in 2011 and from 27 to 32% in 2020 in the subarctic latitudes. Based on the Aura MLS data, the minimal temperatures were 8-12% below normal over the Arctic in 2011 and 8-13% below normal in 2020. The ozone concentration dropped to 23% of the multiyear average at an altitude of 20 km on March 22, 2011, and to 6% at an altitude of 19 km on April 15, 2020, for Alert. A detailed correlation analysis showed that the deviations in the concentrations of water vapor and ozone, water vapor and temperature, and ozone and temperature correlate stronger in 2020 than in 2011. The correlations decrease toward the vortex periphery owing to the exchange of air masses between the Arctic and middle latitudes, becoming weakly significant outside the Arctic circle.

Generation of fogs downstream of the Krasnoyarsk hydropower plant on the Yenisei River during 2020 is studied. Meteorological conditions at the time of fog generation were recorded on the geoportal developed by the authors; water temperatures were taken at a gauging station; fogs were recorded with the help of video surveillance cameras. Data analysis showed generation of advective cooling fogs in summer and advective steam fogs in winter, early spring, and autumn. Cooling fogs are generated due to the cooling of the moist air as the lower atmosphere interacts with a colder moving water surface. Steam fogs result from the advective cooling of water vapor on the river surface by the colder adjacent atmosphere. The spatial distribution of steam fogs was derived from remote sensing data.

The results of mathematical simulation of biogeochemical processes during the autumn cooling of the lake are presented. The influence of wind on the distribution of phyto- and zooplankton, nitrate, ammonium, and phosphate nutrients is studied during the existence of the autumnal thermal bar in Barguzin Bay of Lake Baikal. Numerical simulations show the autumnal thermal bar in combination with the effect of western winds, which act opposite to the thermal front direction, to significantly slow down the transport of plankton biomass toward the central part of the bay.

He methods and results of numerical prediction of the maximum thickness of ice deposits are described. The success of ice deposition forecasts is estimated from calculations based on the WRF-ARW model output for different Russian regions.

An algorithm is developed and, on its basis, a software product is created to control the photon counter and to save the data from recording system of the lidar’s receiving channel at wavelengths of 299/341 nm in atmospheric sensing with a spatial resolution from 1.5 to 150 m. The main software options are: device connection check; receiving lidar sensing data; data digitization; graphical displaying; data filing; conversion of .dat into .txt file format. The software product is experimentally tested along with the mobile ozone lidar receiver unit, incorporated into the software part of the measurement complex of the Siberian Lidar Station. The receiver unit of the mobile ozone lidar comprises a photon counter PHCOUNT_4Е and Hamamatsu photoelectronic multipliers H12386-210. We present the atmospheric lidar sensing data and an ozone concentration profile retrieved in 2022.

The effect of collisional line broadening on the accuracy of tropospheric (0-11 km) temperature measurements with pure rotational Raman (PPR) lidars at their absolute calibration by spectroscopic parameters was estimated via numerical simulation. The simulation was performed for five sets of spectral filters (SF) with different passbands in a lidar spectral selection unit and an outgoing laser signal wavelength of 355 nm. It is shown that the unavoidable absolute calibration error can reach values from 0.14 to 0.44 K (depending on the SF set) when ignoring the N₂ and O₂ PRR line broadening. The line broadening can be neglected if only one PRR line is extracted in each of the two lidar channels (for example, using a Fabry-Perot interferometer).

The article describes the lab-scale testing of dynamic instability in a block placed on a rough slope surface and subjected to small-amplitude vibrations. It is shown that the macroscopic sliding evolution is well-presented using equations of creep with the properly selected constants. According to the testing data, the necessary condition of the dynamic failure is the critical displacement along the slope and the certain creep rate. The critical displacement appears to exceed greatly the typical value when the sliding surface transits to the residual shear resistance. It is found that the landslide body instability develops at the late stage due to the phenomenon of reduction in friction at increasing sliding velocity.

The granular and other similar-type materials without cohesion are tested on various mode shearing machines. The complex loading machine with continuous rotation of principal strain axes is described. Loading represents a superposition of the planar and parallel Couette flows (simple shears) between parallel plates rotated at a certain angular rate. The stress and dilatancy data of quartz sand in deformation on the designed equipment are reported. It is found that stresses and dilatancy in cyclic deformation tend to stationary values. The stationary values of dilatancy increase with increasing shearing strain. The stationary deformation stresses change periodically, their average values weakly depend on the cyclic strains and their amplitude increases.