Atmospheric and Oceanic Optics最新文献

The Lorentz–Mie theory describing light scattering by spherical particles was created in 1908. Nevertheless, most of the discoveries made during the last 30 years (e.g., photon jets, Fano resonance, optical anapoles, optical vortices, and acoustic jets) can be described within the framework of this theory. They were “encoded” in the Lorenz–Mie formulas and were just waiting for someone to decipher them. The article briefly discusses a new effect—the superresonance (and the accompanying Fano resonance of an extremely high order) in dielectric mesoscale spheres. Superresonance allows to generate magnetic fields with giant intensity at “hot points” (poles) of a dielectric sphere. This effect also can be explained using the Lorentz–Mie theory. However, this effect remained hidden inside the exact solution of this theory for almost 120 years!

The paper solves the problem of deriving the relationship between the variability of statistical characteristics of atmospheric parameters measured by GNSS receivers and the characteristics of convective processes based on monitoring data near the Kazan city for 2013–2021. The GNSS monitoring results are compared with the convective indices, which are physical and statistical parameters of instability, calculated from ERA5 reanalysis: upward vertical velocity, vortex generation parameter, and WMAXSHEAR. Statistical characteristics of the horizontal gradient of the zenith tropospheric delay are shown to significantly change under conditions of deep convection. The results of the work can be used to develop a technique for sub-satellite monitoring of convective processes in the tasks of operational forecasting of severe weather phenomena.

The effects of atmospheric aerosol, including smoke, on cloudiness are of great interest for understanding the current climate changes. However, the radiative effect of Siberian biomass burning aerosol (SBBA) on clouds in the Arctic has been little studied. Based on simulation with the CHIMERE chemistry transport model and WRF meteorological model, we analyze the processes responsible for origination of the semidirect radiative effect (SDRE) of smoke from Siberian wildfires over snow–ice surfaces in the Arctic, including time- and space-averaged changes in the radiative fluxes, cloud parameters in different cloud levels, and some meteorological characteristics associated with cloud generation due to the radiative effect of (SBBA). The results show that solar radiation scattering by SBBA particles increases the static stability of the atmosphere at altitudes of 2–4 km and suppresses vertical turbulent motions, which decreases the rate of water condensation, the optical thickness of clouds, and the mixing ratio in the medium- and partly lower-level clouds. The decrease in the optical thickness of clouds, in turn, causes origination of positive SDRE of SBBA at the top and bottom of the atmosphere. Radiation absorption by SBBA particles does not play an essential role in these processes, although additionally changes meteorological characteristics. Our results expand fundamental knowledge of aerosol–cloud interactions in the Arctic and can be used for improving climate models.

Tasks which require information about energy characteristics of rains and methods for acquiring this information are briefly reviewed. A technique is suggested for estimating the kinetic energy transferred by hydrometeors based on microstructural characteristics of rainfall obtained with an OPTIOS optical precipitation gage. The technique is tested with measurement data received during a heavy rainfall occurred in Tomsk on July 22, 2023. The influence of different microstructural parameters on the amount of kinetic energy brought by raindrops to the underlying surface is analyzed. The results are compared with the values obtained by simplified methods. It is concluded that the capabilities of the optical precipitation gage make it a useful tool for solving tasks where accurate assessments of rainfall energy characteristics are required.

To assess the relative contribution of key chemical and physical processes to the observed variability in climate and atmospheric gas composition from the 1980s to the 2020s, numerical experiments were conducted using the chemical-climatic model SOCOLv3. The study investigated factors determining the variability of principal climatic characteristics, including changes in the concentrations of ozone-depleting substances; variations in greenhouse gas concentrations, sea surface temperature, and sea ice extent; fluctuations in solar activity; and alterations in atmospheric aerosol content. Calculations for scenarios considering each of these factors individually, as well as a baseline model experiment accounting for all factors concurrently, were performed to evaluate the relative roles of these factors. The outcomes of the numerical experiments determined the relative contributions of different factors to changes in tropospheric temperature, lower stratospheric temperature, and ozone content from 1980 to 2020. The results of the model calculations were then compared with data from SBUV satellite measurements.

The effects of the quasi-biennial oscillation (QBO) of the zonal wind in the equatorial stratosphere and the El Niño Southern Oscillation (ENSO) on the dynamic state of the stratosphere in winter and the evolvement of sudden stratospheric warming (SSW) are studied in numerical experiments with the nonlinear general circulation model of the middle and upper atmosphere (MUAM) for winter conditions of the Northern Hemisphere (January–February). The sensitivity of the model fields of zonal wind, temperature, and geopotential to ENSO and QBO phases is estimated. The statistics of observed SSWs and their evolution differ depending on the combination of phases, e.g., the largest number of SSWs is observed under the combination of El Niño and an easterly phase of QBO; major SSWs are not reproduced by the model under the combination of La Niña and a westerly phase of QBO. The fields of hydrodynamic parameters have been averaged for combinations of El Niño/easterly phase of QBO, El Niño/westerly phase of QBO, and La Niña/easterly phase of QBO to analyze the characteristic features of the model “climatic” SSWs. The analysis shows the maximal temperature rise in the stratosphere and cooling in the mesosphere in the model under El Niño and the eastern phase of QBO; wind weakening is maximal under El Niño and the western phase of QBO. The highest planetary wave amplitudes are modeled under easterly QBO phases regardless of the ENSO phase. The results can be used in climate forecasting on time scales from one month to decades.

Physical processes occurring in air disperse media with solid particles in a laser channel during thermal emission of electrons from the particle surface and primary optical breakdown are considered. Changes in the refractive index during the formation of plasma halos around radiation-heated microparticles are estimated. A possibility of weak ionization of an air medium at a distance of several centimeters from the breakdown area due to the ionization of NO molecules and thermochemical reactions is shown.

The joint dynamics of phytoplankton parameters (primary production, specific growth rate, and biomass) and amount of precipitation in coastal regions and on the shelf in the northern part of the Black Sea in 1998–2015 are studied based on satellite data (SG) (GPCPMON) GPCP Version 3.2, TRMM TMPA (3B42RT), SeaWiFS from 1998 to 2010, MODIS-Aqua from 2002 to 2015, and MODIS-Terra from 2000 to 2015. The phytoplankton parameters are calculated according to earlier developed models. Their monthly average values, as well as bi-weekly and daily values of atmospheric precipitation are assessed. As a result of the study, insignificance of the part of atmospheric precipitation in the variability of phytoplankton parameters on vast water areas and long time periods is revealed. It sometimes increases to 30% in offshore areas in the presence of influxes of large rivers. The effect of atmospheric precipitation on the biological productivity of phytoplankton in small bounded water areas and short time periods is more pronounced. According to our data for 18 years, a correlation between the specific growth rate and precipitation on the Black Sea shelf is stronger in winter than in other seasons; the correlations of biomass and primary production of phytoplankton with atmospheric precipitation are less pronounced. The specific growth rate of phytoplankton correlates with precipitation stronger than other phytoplankton parameters under study. An increase in the amount of precipitation over previous level with the monthly averages above 0.6 mm/day increases the specific growth rate or maintained it at the same level. The increase in the specific growth rate is not the same everywhere and not proportional to the amount of atmospheric precipitation. This witnesses the influence of many factors on the phytoplankton parameters; however, precipitation could be an additional stimulating factor.

This work presents the analysis of the spatial distribution of number concentration, size distribution, and chemical composition of aerosol particles measured for the first time over the seas of the Russian Arctic. Various types of vertical distribution of the number concentration were recorded, characteristic of both coastal marine and continental areas. Most of them turned out to be of the continental type. Attention is also drawn to the almost complete absence of coarse particles above 2–3 km over all seas. The chemical composition of the Arctic aerosol at altitudes of both 200 m and 5000 m contains ions that can be referred to as both marine and continental. The identifiable carbon- and salt-free elemental part of the aerosol over the Arctic is 3–4 times larger than that of ions. Over all seas and at both altitudes, the Arctic aerosols mainly contain elements of terrigenous origin – Al, Cu, Fe, and Si. Over almost all seas, except the Barents Sea, Si is dominant in the elemental composition of the aerosol, its contribution over the Chukchi Sea reaching 85%. The analysis of backward trajectories showed that in all cases considered, whether the aerosol was formed over the continent or sea, air trajectories passed both over sea and over land. In this case, the formed particles could be enriched with additional ions and elements along their pathway. This work completes a cycle of the papers, devoted to studying air composition, which was carried out over the seas of the Russian Arctic in September 2020. Our results can be used to model the atmospheric processes occurring in the Arctic under the conditions of changing climate.

For short-term forecasting of weather periods characterized by strong winds with gusts, it is proposed to use results of calculations based on the TSUNM3 (Tomsk State University Nonhydrostatic Mesoscale Meteorological Model) local weather numerical prediction model in combination with semiempirical formulas for estimating the scales of wind gust speeds. The comparison of the calculations and observations of meteorological parameters obtained for the conditions under consideration at the meteorological stations of the Atmosfera Common Use Center of the Institute of Atmospheric Optics, the AMMS-RF (airfield meteorological measuring system) of the Tomsk airport, and meteorological stations of the Tomsk CHEM showed the prospects of using the model for numerical forecasting of this dangerous weather phenomenon. The results of the work are to be used for the development of an information and predictive system for early warning of dangerous wind gusts.