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Volume 61, Nº 6 (2025)
Articles
FOOTPRINT FOR SURFACE FLUXES: CONCEPT AND ASSESSMENT METHODS
Resumo
The area of turbulent flux formation or the coverage zone when measuring from masts is subject to spatial and temporal variability. The need for accurately assessing the flux formation area or footprint has significantly increased with the establishment of long-term monitoring stations for turbulent exchange over forests and other heterogeneous landscapes and the creation of observation networks to assess the intensity of matter and energy exchange between ecosystems and the atmosphere (e.g., FLUXNET, AsiaFlux, RuFlux). The footprint plays a crucial role in optimizing instrument placement, interpreting time series of measured fluxes, analyzing the variability of fluxes in response to changes in the underlying surface, and evaluating the quality of the data collected. However, estimating the footprint is challenging due to the diversity of the studied substances’ fluxes and concentrations. This article provides an overview of the available modeling methods for footprints, discussing their advantages and disadvantages. It also identifies current challenges and suggests ways to improve existing approaches.
Izvestiya, Atmospheric and Oceanic Physics. 2025;61(6):701-736
701-736
GENERAL CIRCULATION AND BAROCLINIC WAVES IN THE ATMOSPHERE OF ZONALLY UNIFORM EARTH-LIKE MODEL PLANETS
Resumo
The boundary conditions at the Earth’s surface have a significant influence on the planetary and synoptic scale flows that form in the atmosphere. In the Earth’s real atmosphere, it is difficult to isolate and study the influence of boundary conditions because the spatial structure of large-scale flows and their temporal variations are strongly influenced by the distribution of land and ocean, surface relief, the hydrological cycle, and other factors. It is possible to study the role of the underlying surface using idealised models of Earth-like planets. This paper presents a comparative analysis of the structure and dynamics of the atmospheric general circulation and baroclinic waves for idealised, zonally homogeneous planets. Numerical experiments are performed using the WRF-ARW software package for the built-in characteristics of the Earth’s atmosphere and the terrestrial parameters of planetary motion and insolation. Three model configurations are considered, namely a desert planet, a desert planet with an equatorial ocean, and an aquaplanet with a fixed meridional temperature distribution. It is shown that the desert planet is characterised by strong seasonal variations, leading to remarkable features both in the structure of the mean general circulation and in the distribution of velocity and temperature pulsations. On a desert planet with an equatorial ocean, the meridional velocity and temperature pulsations are similar to those observed in the Earth’s atmosphere. They are concentrated at mid-latitudes and separated by height, with the maximum of temperature pulsations in the lower part of the troposphere and the maximum of velocity in its upper part. On the aquaplanet, the temperature pulsations are significantly smaller in amplitude and shifted into the middle layers of the troposphere. The simulations have shown that, despite zonally homogeneous boundary conditions and the absence of relief, the intensity, lifetime, phase and group velocity of the baroclinic waves vary significantly on all the model planets considered. On a desert planet and a mixed-type planet, there is a pronounced season of maximum wave activity. On the aquaplanet, there are no strong seasonal variations, but long intervals of westward blocking are observed. The spectral composition of the baroclinic waves and their seasonal variability have been analysed.
Izvestiya, Atmospheric and Oceanic Physics. 2025;61(6):737-750
737-750
INTENSIFICATION OF UPPER-TROSPHERIC CURRENTS DUE TO EKMAN FRICTION
Resumo
The dynamics of zonal quasi-geostrophic currents was studied within the framework of a two-level quasi-geostrophic model with bottom friction. It is shown that due to friction the flow velocity at the lower level drops to zero, while the velocity at the upper level increases. An analytical expression for the maximum flow velocity at the upper level is obtained, and the dependence of the amplification factor on the structure of the initial velocity disturbance is investigated. A similar result is obtained within the framework of a continuous surface geostrophic model using the long-wave approximation. An analytical solution is constructed that describes the transformation of the zonal flow into an intense upper-tropospheric flow. Thus, it is shown that Ekman friction is one of the important mechanisms that contribute to the intensification of currents at the upper level.
Izvestiya, Atmospheric and Oceanic Physics. 2025;61(6):751-757
751-757
ABOUT THE MOVEMENT OF PASSIVE ADMIXTURE IN A STRATIFIED ZONAL FLOW ABOVE AN ISOLATED SUBMARINE GUYOT
Resumo
Within the framework of a three-layer quasi-geostrophic model in the f-plane approximation, a numerical study of the effect of an isolated submarine obstacle on the movement of surface, subsurface and deep patches of a passive admixture transported by a vertically homogeneous zonal current was carried out. The influence of density stratification and velocity of the external current on size of the topographic vortex forming above the obstacle is investigated. The role of the initial sizes and forms admixture spots on the resulting pollution distribution pattern is revealed.
Izvestiya, Atmospheric and Oceanic Physics. 2025;61(6):758–769
758–769
PROPAGATION OF PULSED ACOUSTIC WAVES IN THE ATMOSPHERIC GROUND LAYER. PART 2: INFLUENCE OF THE UNDERLYING SURFACE ON THE SHAPE AND PARAMETERS OF ACOUSTIC PULSES
Resumo
The results of experimental studies of the propagation of a nonlinear acoustic wave in the surface layer of the atmosphere are analyzed. The influence of the underlying surface and vegetation on the waveform, as well as on its amplitude and width of the frontal region, is considered. A large-scale effect of the interaction of a nonlinear acoustic wave with vegetation has been revealed. It is shown that the expansion of the front region of the wave obeys the law of energy similarity. The necessity of searching for a mechanism that causes such a character of wave development is noted.
Izvestiya, Atmospheric and Oceanic Physics. 2025;61(6):770-785
770-785
MODE STRUCTURE OF INTERNAL GRAVITY WAVES GENERATED BY LOCALIZED SOURCES IN A STRATIFIED OCEAN WITH SHEARS FLOWS
Resumo
The aim of the work is to study the mode structure of solutions describing the generation of internal gravity waves in stratified media with model distributions of the buoyancy frequency and background shear currents, which allows us to determine the main qualitative characteristics of the behavior of dispersion relations at small wave numbers depending on the mode number. The problem of constructing solutions describing the generation of linear internal gravity waves in a layer of a stratified medium of finite depth with model distributions of the buoyancy frequency and background shear current is considered. Under the assumption of the Miles–Howard stability for the Richardson number, the corresponding dispersion dependences are studied. It is shown that, depending on the parameters of the linear shear current, the dispersion curves of the wave modes can have qualitatively different asymptotic representations at small wave numbers. The dispersion curves of a finite number of modes describing waves with a limited length, at small values of the wave number, admit expansions in even powers of a small parameter. The dispersion curves of the remaining modes, corresponding to waves with an arbitrarily large length, are expanded in a series in odd powers of small wave numbers. The phase structure of the wave fields is studied depending on the mode number and the main characteristics of the shear currents. Analytical estimates are obtained that make it possible, depending on the parameters of the model flow, to find the number of the wave mode that divides the entire existing set of wave modes into limited and long-wave ones.
Izvestiya, Atmospheric and Oceanic Physics. 2025;61(6):786–796
786–796
PHOTOCHEMICAL/ CHEMICAL EQUILIBRIUM OF ATMOSPHERIC TRACE GASES: A REVIEW OF ANALYSIS METHODS AND APPLICATIONS
Resumo
The paper presents a review of studies in which the equilibrium of chemically active atmospheric gases is used in the retrieval of unmeasurable (poorly measured) characteristics of the troposphere, stratosphere and mesosphere – lower thermosphere altitudes. We summarize our studies that develop mathematically correct analysis of trace gas equilibrium which involves numerical modeling, including global 3D chemical transport modeling.
Izvestiya, Atmospheric and Oceanic Physics. 2025;61(6):797–814
797–814
VARIABILITY OF METHANE CONCENTRATION IN THE ARCTIC ATMOSPHERE FROM SHIPBORNE MEASUREMENTS IN 2023
Resumo
Arctic temperatures have in recent decades risen faster than the global average, threatening the large carbon pools locked in the Arctic permafrost. Atmospheric composition monitoring has become a priority, but it is extremely difficult to set up in such remote regions, especially over the Arctic seas. These observations are limited by the length of the navigation season and the logistical difficulties of sampling and measuring atmospheric composition. In this study, atmospheric CH4 concentrations were measured over 28 days in the fall and early winter of 2023. The main study areas were the Barents Sea and the southern regions of the Kara Sea, with special attention paid to the bays of the western coast of the Novaya Zemlya archipelago. During the study period, atmospheric CH4 concentrations ranged from 2.018 to 2.122 ppm, with an average value of 2.039 ± 0.013 ppm. Variations in atmospheric CH4 in the surface layer were mainly due to meteorological conditions, as well as the geographical location of the vessel and the time of measurements. High-resolution coupled measurements of marine and atmospheric CH4 data are critical for understanding the scale of methane emissions at the ocean-atmosphere interface, especially in winter when the mixing layer increases, convection intensifies, and more methane from the water column can enter the atmosphere. In addition, our data can be used as input parameters for climate models.
Izvestiya, Atmospheric and Oceanic Physics. 2025;61(6):815–832
815–832
URBAN CLIMATE RESEARCH IN RUSSIAN FEDERATION IN XXI CENTURY
Resumo
This review is an analysis of high-profile papers that have appeared in the last two decades, which analyses the characteristics of climate and microclimate of cities in the Russian Federation from different perspectives. The review is divided into five subsections: from the impact of climate change on air quality and recurrence of hazardous weather events to the characteristics of urban heat island, its impact on energy and thermal comfort conditions for the population, as well as the climate of cities in the Arctic zone of the Russian Federation. It is noted that more than half of the papers are devoted to studies of the climate of two federal cities in the Russian Federation, Moscow and St. Petersburg, which can be explained by the geographical institutional affiliation of the research teams conducting the studies. On the other hand, among the millionaire cities of the Russian Federation there are also those that have not been subjected to close study from the climatological point of view (in the periodic scientific literature) in the last more than two decades (e.g., Samara). All the above-mentioned features point to the lack of studies of urban climate from the beginning of the XXI century to the current moment at different spatial scales.
Izvestiya, Atmospheric and Oceanic Physics. 2025;61(6):833-852
833-852