Atmospheric and Oceanic Optics最新文献

Laser sensing data are used to analyze the variations in the base height of low-level clouds and cumulonimbus clouds in Western Siberia for 2010–2021. It is found that, on the whole, the base height of lower clouds decreases and the base height of cumulonimbus clouds increases. The base height of lower clouds increases from north toward south. The distribution of the height of cumulonimbus clouds seems to be more meridional in character. The seasonal behavior of the base height of lower and cumulonimbus clouds in the south of the territory shows a maximum in summer months. In the center and north there are two maxima: in summer and spring for lower clouds and in winter and summer for cumulonimbus clouds. The cluster analysis showed that the base heights of cumulonimbus clouds, measured at diverse stations, strongly differ. Presumably, this is due to different characters of the underlying surface, as well as to regional features of atmospheric circulation and convective processes.

Water vapor plays a key role in different climate-forming processes at various altitudes in the Earth’s atmosphere. Monitoring of water vapor isotopologues provides information on the atmospheric hydrological cycle. It helps to study the processes associated with evaporation and condensation which control the moisture in the troposphere and the troposphere–stratosphere water exchange. The temporal variability of water vapor isotopologues (H₂O and δD) in Peterhof in 2009–2020 is analyzed for the first time on the basis of ground-based Bruker IFS 125HR Fourier spectrometer measurements of solar IR radiation. For both H₂O and δD, the maxima occur in summer and the minima in winter; the largest variability of H₂O is observed in summer, and of δD, in winter months due to the climatic features of St. Petersburg, i.e., the origin and history of incoming air masses. The database of water vapor isotopic composition in the vicinity of St. Petersburg can be used in models of the general circulation of the atmosphere to improve the accuracy of weather forecasting and long-term changes in the regional climate.

We consider the distribution of tropospheric ozone on the territory of Russia in 2022 using data from 33 stations located in different physical and geographical zones, as well as its vertical distribution from results of aircraft sensing. It was shown that measurements at all measurement sites exceeded the maximum permissible daily average concentrations, determined by the national hygienic standard. In some regions, the excess over the maximum permissible concentrations of the working zone and over the maximum one-time hourly average concentrations is recorded, so that the population should be broadly warned about the monitoring results and measures should be taken to reduce the level of ozone concentration in the surface air layer.

Satellite data on black carbon (BC) emissions into the atmosphere are used to derive model estimates of the of BC concentrations in the surface atmosphere for four regions of the Russian Arctic: on the Kola Peninsula, in Arkhangelsk oblast, and on the territories of Nenets and Gydan nature reserves in winter and summer 2000–2016. The long-range atmospheric BC transport is analyzed using the authors’ methodology for calculating the function of sensitivity to potential sources of submicron aerosol based on the statistics of back trajectories of air mass transport. On the whole, the contributions of anthropogenic sources to BC content in air in each region considered here predominate over the contributions of wildfires. The BC concentration in surface air is maximal over the Nenets Nature Reserve and over the Pechora Sea basin, where the main sources of this admixture all year round are flares from associated gas combustion in the nearest Russia biggest oil and gas provinces. We present the average, median, and maximal BC concentrations in the surface air in winter and summer, calculated from interannual variations in this index, caused by the differences in air mass circulations, carrying this admixture, as well as from spatial and interannual variations in BC emissions from fires.

Lidar is an important tool for studying atmospheric aerosol; it is widely used in studying the propagation of aerosol pollution in the atmosphere. During environmental monitoring, especially with a mobile lidar, it is important not only to detect a pollutant, but also to determine the spatial coordinates of its source and the propagation dynamics. In the work, we suggest a technique for calculating the coordinates of an object under study from the lidar coordinates, sensing direction, and the distance between the lidar and the object. The software implementation of the technique and an example of its application in the design of an auxiliary lidar system are described.

The results of laboratory experiments on determining the characteristics of convective turbulence over a heated metal surface at different heights and temperatures are presented. We used the high-speed thermography and a high-speed IR camera, which allowed imaging the temperature field of low-inertia paper targets hung up above the heated surface simultaneously throughout the vertical plane of the field of view of the camera. Based on fluctuations in the temperature field of the target surface, we determined the heat transfer coefficient, the convective flux intensity, the total flux, and the amount of heat generated during measurements at different heights above the surface. The energy spectra of convective turbulence are plotted under various turbulent conditions. The analysis of the turbulence spectra shows the presence of an inertial interval with a slope close to the 8/3 power law for all considered heights above the heated surface, temperatures, and turbulence conditions. Characteristics of convective turbulence we found can be used when testing different laser beam adaptive optics control systems, studying the propagation of vortex laser beams and combustion centers, which are also characterized by convective turbulence with further transition to atmospheric turbulence induced by the combustion energy.

The potential and advantages of an additional Raman channel in the IR spectral region for the determination of microphysical parameters of aerosol are studied. Features of the joint retrieval of the complex refractive index m = m_real + i × m_image and the bimodal spherical particle size distribution function U(r) from lidar data are considered. A possibility of estimating m + U(r) is studied for weakly absorbing particles for m_image ≤ 0.010 when m^fine ≠ m^coarse. The algorithms are tested for one m^fine = 1.50 + i × 0.01 and nine m^coarse (m_real = 1.40, 1.50, and 1.60; m_image = 0.0001, 0.001, and 0.01). In order to take into account the influence of the contribution from the modal particles to the total concentration, 462 empirical models of U(r) are used.

A comparative analysis of open source data on the water spectral lines intensities in the frequency range from 0 to 1.75 THz was carried out. The analyzed data are significant for radiation propagation models. The calculations by the method of effective Hamiltonians and the variational method, as well as experimental data were taken into account. The uncertainty of intensity was found to be less than 2% for lines of the ground vibrational state with an intensity of more than 10⁻²⁷ cm/molecule and about 5–10% for weaker lines. For strong (more than 10⁻²⁶ cm/molecule) rotational lines of the ν₂ state, the intensity uncertainty ranged from 2 to 5% and increased up to 5–10% for weak lines. For all rotational lines of the 2ν₂, ν₁, and ν₃ states, the uncertainty was no more than 5–10%. The presented data show that most of the considered lines can be assigned a higher (by 1–2 steps according to the classification adopted in HITRAN) category of intensity accuracy.

The new coronavirus pneumonia has rapidly spread around the world. The World Health Organization emphasized that the SARS-CoV-2 coronavirus spreads mainly between people who are in close contact with each other, as well as in the case of touching contaminated surfaces followed by touching the eyes, nose, or mouth without first cleaning the hands. Possible permanent sources of the spread of the virus can be gathering of patients in hospitals in the case of noncompliance with the requirements for organizing the functioning of a hospital. Meteorological conditions can be a key factor influencing the spread of the virus in the case of an accidental release of virus-containing aerosol from such a hospital. Simulations are carried out with modern methods for solving a system of differential equations of the atmospheric boundary layer, which are adapted to describe the distribution of harmful atmospheric impurities over a real complex terrain considering urban buildings of various heights, forests, reservoirs, changing meteorological conditions, and many other factors.