Atmospheric and Oceanic Optics最新文献

Сlimate warming in the Arctic is several times faster than in other regions of the globe. This сan be the result of strengthening of feedbacks between climate and atmospheric composition. However, there are very few data on changes in the concentration of climatically active substances in this region. Therefore, to fill the gap in data on the vertical distribution of gas and aerosol composition of air over the Russian Arctic, an airborne survey of the atmosphere and water surface over all the Russian Arctic Ocean seas was performed with use of the Tu-134 Optik aircraft laboratory in September 2020. This paper analyzes the spatial distribution of gas and aerosol composition in the Arctic troposphere. It is shown that during the experiment, the CO₂ mixing ratio increased in the near-water and boundary layers and decreased in the free troposphere from west to east. The methane content in the near-water layer decreased in the same direction. Concentrations of CO, NO_X, and SO₂ in the Russian Arctic were very low, which was typical for remote background areas. All aerosol fractions also showed a decrease in their content from west to east.

A formula has been derived which connects the structural constant of temperature fluctuations with the dissipation rate of kinetic energy of turbulence not through the turbulent thermal diffusivity but through the vertical gradients of average wind velocity and air temperature and the turbulent Prandtl number. To estimate the structural constant of temperature using this formula, a model based on generalization of known data on the turbulent Prandtl number as a function of the gradient Richardson number is proposed. It has been experimentally shown that the time series of the structural constant of temperature, which is calculated using the proposed formula and independently found from the spectra of temperature fluctuations based on measurements of wind velocity and air temperature with sonic anemometers at two altitudes, are consistent with each other. This confirms correctness of the theoretical constructions the generalized results of which serve as the basis for the model dependence of the turbulent Prandtl number on the gradient Richardson number and opens possibilities of remote determination of the structural constant of temperature from measurements of wind velocity and temperature.

The intensity and frequency of severe weather events are currently increasing in Western Siberia. Weather Research and Forecasting (WRF) atmospheric model makes it possible to study these phenomena, in particular, for warning about their occurrence. This article defines a set of WRF parameterization schemes which provide a full-fledged analysis of the causes of occurrence and monitor the further development of severe weather events. This set of schemes ensures correct operation of WRF model under conditions corresponding to severe weather events. The paper details two weather events with such severe phenomena as very strong wind, very heavy rainfall, prolonged heavy rain, and abnormally cold weather, which occurred in Western Siberia on April 29–30, 2019, and December 25–26, 2020.

The technology of preparing the chemical raw material or fuel from associated petroleum gas envisages combustion of associated gas in low-pressure flares, emitting into the atmosphere soot (C), nitrogen dioxide (NO₂), carbon dioxide (CO₂), and methane (CH₄). To estimate the state of the atmosphere in the region of oil-gas production, a comprehensive approach is suggested to simulate the pollutant dispersal fields in the surface air layer from flare units on the territory of the Mamontovskoye field of the Nefteyugansk district of the KhMAO. This approach incorporates the simulation of pollutant (С, NO₂, CO₂, and CH₄) concentrations using UPRZA Eco-Center software together with ground-based data (the content of organic compounds in soils) and satellite (AIRS) data (greenhouse gas concentrations). This approach enables comprehensive studies of the state of the natural environment in remote northern oil and gas producing areas on the basis of satellite and ground-based data.

Results of experiments on determining turbulence parameters of a stratified atmospheric boundary layer by means of remote sensing are presented. The height–time distributions of the dissipation rate of kinetic energy of turbulence and those of the structural constant of turbulent fluctuations of temperature obtained using a coherent wind lidar and a temperature radiometer are compared with height variations in parameters characterizing atmospheric stratification. It is shown that the dissipation rate which determines the intensity of wind turbulence decreases in the boundary layer with height for all types of thermal stratification. The intensity of turbulent fluctuations of temperature depends to a greater extent on variations in thermodynamic stability in the atmosphere. If the thermal instability of the atmosphere at larger heights exceeds that in lower layers, then the structural constant of temperature fluctuations can not decrease but increase with height. In accordance with height variations in the structural constant of temperature, values of the structural constant of turbulent pulsations of the refractive index can also increase with height and differ from those predicted based on known models.

Atmospheric trace gases (ATGs) are optically active constituents of the atmosphere. ATGs have a great influence on atmospheric processes: transformation of solar radiation, weather formation, air pollution by industrial emissions, and propagation of optical waves. Ozone occupies a special place among ATGs. The ozone layer plays the role of natural protection of the planet from shortwave solar radiation. Therefore, monitoring of the ozonosphere by ground-based and satellite instruments allows us to obtain the most reliable data on the state of the atmosphere and, in particular, the ozone layer. The solution of this urgent problem is possible only with permanent improvement of the hardware base and perfection of methodological approaches to scientific research of the atmosphere. In this work, a number of measurements were carried out using a mobile ozone lidar at the sensing wavelengths of 299/341 nm in the altitude range 0.1–12 km at the Siberian lidar station (SLS). Vertical ozone profiles retrieved from lidar and meteorological satellite data of the European Space Agency (MetOp) obtained in 2023 were compared. The comparisons showed that the average relative difference between the profiles varies from −65.6% to 15.3% at altitudes from 0.1 km to 12 km. The comparison results confirm good prospects for using these ozone sensing wavelengths in the altitude range 0.1–5 km, previously uncovered by the SLS. The results will be used in modeling the vertical distribution of ozone concentration and in assessing the ecological state of the atmosphere in the Tomsk oblast.

Solving of the light scattering problem of atmospheric ice crystals is necessary for interpreting data of laser sensing of the atmosphere. Light backscattering matrices for cloud ice crystals of arbitrary form of 10 to 300 μm in size with the number of faces of 15, 20, and 40 are calculated within the physical optics approximation for the case of arbitrary spatial orientation of particles and single scattering of light at wavelengths of 0.532 and 1.064 μm. According to the statistical analysis of crystals, their optical properties slightly differ. Optical properties of an etalon particle taken from the IAO SB RAS data bank are shown to satisfy the above distribution, thus confirming the validity of using the database for the case of a large set of particles with the number of faces from 15 to 40. The results are necessary for constructing algorithms for interrelating data of lidar sensing of cirrus clouds.

Ozone is one of the important trace gases of the Earth’s atmosphere. This study analyses ground-based synergetic MW + IR method for remote measurements of ozone using ground-based instruments at Peterhof (St.-Petersburg State University): MW ozonometer and Bruker IFS-125HR Infrared Fourier Transform Spectrometer. Numerical estimates of the errors and vertical resolution of the remote measurements showed that uncertainties of remote ozone measurements vary from 5 to 20% or more at different altitudes. The vertical resolution of the MW + IR method varies from ∼10 to ∼12 km. These estimates show the potential for monitoring ozone content in Peterhof combining ground-based MW and IR measurements.

Two methods for stratospheric polar vortex delineation are compared by the main vortex characteristics they provide: vortex area, average wind speed at the edge, mean temperature inside the vortex. One of the methods is based on the geopotential, and another one is based on the potential vorticity (PV). Both methods use ERA5 reanalysis data on isobaric and isentropic surfaces. The geopotential method yields 1.3‑time higher vortex area for the Arctic and 1.14-time higher for Antarctica than the PV method. The estimates of the average wind speed at the vortex edge are very close: the wind speed by PV method is 5% higher than by the geopotential method for the Arctic and 3% higher in Antarctic. Mean temperature inside the vortex by PV method is 1% lower in both the Arctic and Antarctica. The maximal differences in the estimates of the vortex area are 25.52 million km² in the Arctic (on November 23, 2022, on the 600-K isentropic surface) and 23.78 million km² in Antarctica (on December 14, 2022, on the 475-K surface). These differences increase with the altitude: from 4.23 million km² on the 475-K surface to 10.24 million km² on the 600-K surface in the Arctic, and from 4.91 million km² on the 475-K surface to 6.17 million km² on the 600-K surface in Antarctica. The significant difference in the vortex area confirms a need in careful selection of the delineation method when studying polar vortices.

The history of the creation of a turbulent lidar at V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, began 11 years ago, when a bulky laboratory setup enabled experimentally detecting the backscatter enhancement (BSE) effect in a turbulent atmosphere for the first time. Subsequently, a number of design solutions were suggested to improve the lidar, which made it possible to reduce its size and increase its reliability. The main design features of the turbulent lidar, which is a new type of laser locator, are the coincidence of the optical axes of the transmitter and receiver, the presence of an additional receiving channel, and operation in the photon counting mode with the accumulation of echo signals. In this work, the lidar sounding technique is described; an algorithm for retrieving the profile of the structural characteristic of turbulent fluctuations of the refractive index of air from the ratio of lidar echoes is developed; the experimental technique is verified and the lidar data are compared with the readings of a solar radiometer and a scintillometer. Further development of the turbulent lidar sounding technique is to enable ground-based remote monitoring of the turbulence intensity in the atmospheric boundary layer, e.g., along glide paths at airports, distant early detection of clear air turbulence from an aircraft, etc.