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For the first time, by using a regression procedure, we analyzed the solar activity dependence of the winter anomaly intensity in the ionospheric F2-layer peak electron density (NmF2) and in the Total Electron Content (TEC) on a global scale. We used the data from global ionospheric maps for 1998–2015, from GPS radio occultation observations with COSMIC, CHAMP, and GRACE satellites for 2001–2015, and ground-based ionosonde data. The fundamental features of the winter anomaly in NmF2 and in TEC (spatial distribution and solar activity dependence) are similar for these parameters. We determined the regions, where the winter anomaly may be observed in principle, and the solar activity level, at which the winter anomaly may be recorded in different sectors. A growth in geomagnetic disturbance or in the solar activity level is shown to facilitate the winter anomaly intensity increase. Longitudinal variations in the winter anomaly intensity do not conform partly to the generally accepted Rishbeth theory. We consider the obtained results in the context of spatial and solar cycle variations in O/N2 ratio and thermospheric meridional wind. Additionally, we briefly discuss different definitions of the winter anomaly.

This study investigates subauroral phenomena during the main phase of the 10 May 2024 geomagnetic storm using a combination of ground-based observations from the WD IZMIRAN observatory (magnetometer, ionosonde, and all-sky imager) and Global Self-consistent Model of the Thermosphere, Ionosphere, Protonosphere (GSM TIP) simulations. During 18:00–20:00 UT, we identified the simultaneous occurrence of ionospheric signatures of Polarization Jets (PJ)/Sub-Auroral Ion Drifts (SAID) and Strong Thermal Emission Velocity Enhancement (STEVE) over Kaliningrad, consistent with previously reported PJ/SAID identification from DMSP drift velocity measurements. This identification is supported by: (1) characteristic purple emissions (clearly visible in all three channels) moving rapidly westward; (2) U-shaped structures in ionogram sequences; (3) the reproduction of supersonic westward plasma drifts within a narrow latitudinal band by the first-principles model; and (4) observed and simulated significant Ne depletion. The estimated ion drift velocity from all-sky imaging (assuming an emission altitude of 200 km) is consistent with GSM TIP simulations, which predicted PJ/SAID velocities of 750 m/s driven by a latitudinally narrow ( 3°) but longitudinally extended (>50°) poleward electric field (40 mV/m). Simulations reveal that this PJ/SAID phenomenon causes a reversal of the zonal thermospheric wind at 250 km and induces Ne disturbances across the 200–700 km altitude range. The electron temperature enhancement (up to 1500 K) exhibits a “falling drop” shape, peaking at 350 km, while ion heating exceeds 150 K. The neutral temperature shows a dual response: frictional heating at 120–160 km and localized cooling at 175–250 km due to drop in electron density. Additionally, an increase in atomic oxygen concentration was predicted within the 90–200 km range across the PJ/SAID longitudinal sector.

We present results from a mini-survey of dust spectral features arising in galaxies at redshifts 0.5 < z < 1.2 in our James Webb Space Telescope (JWST) mid-infrared spectra of physically unrelated background quasars. We analyze the JWST Mid-infrared Instrument Medium-Resolution Spectrometer spectra of five quasars presented in Klimenko et al. (Paper I) to determine the best-fit silicate mineralogies. Template profile fits to the 10 μm feature suggest the possible presence of crystalline silicates in three of the galaxies. This contrasts with the predominately amorphous silicate grains in the Milky Way diffuse interstellar medium (ISM). We also measure the extinction curves using existing data from UV to mid-IR. Combining our results with past Spitzer IRS studies, we find the following: (i) the 10 μm silicate peak optical depth (τ10) is about 3 times stronger than expected for the local diffuse ISM over the range AV = 0.1–2.0, with τ10/AV = 0.17 ± 0.09. (ii) The relative strength of the UV bump is similar to that in the local ISM. However, the ratio τ10/A2175 is larger (∼0.1–1), and appears to decrease with AV, approaching the Galactic ISM value (∼0.1) at AV ∼ 1.5–2. (iii) There is no significant correlation of τ10/AV with RV. (iv) τ10 is strongly correlated with the gas-phase Mg ii absorption strength for the quasar sightlines. Possible interpretations include that some quasar sightlines probe dust in the circumgalactic medium (CGM), and that dust grains may have been significantly reprocessed in the ISM and CGM under conditions that may differ from those in the local ISM.

Interstellar dust plays a crucial role in gas cooling and molecule formation, influencing galaxy evolution. However, the composition and structure of dust in distant galaxies are still poorly understood. We have started a JWST Mid-Infrared Instrument (MIRI) medium-resolution spectrograph (MRS) program investigating the dust features in gas-rich and dusty galaxies at redshifts z < 1.2, with strong 2175 Å bumps detected in absorption along the lines of sight to distant background quasars. Here, we describe our program strategy, and present MIRI MRS observations of IR dust features at z = 0.5–1.2 in five quasar spectra that form the first part of our full sample. We identify artifacts in MIRI MRS data that affect the background in IFU cubes, and propose methods to reduce their effects. We pay special attention to modeling the quasar mid-IR continuum, which shows significant variation depending on active galactic nucleus morphology, redshift, and black hole mass. Dust in foreground galaxies produces significant absorption from the 10 μm silicate feature in all five quasar spectra. Compared with the average 10 μm silicate feature in the diffuse interstellar medium (ISM) of the Milky Way, we find differences in the absorption peak position, width of the features, and asymmetry of the profiles. A detailed study of these silicate features is presented in our next paper. In two quasar spectra, we tentatively detect weak IR features near 3.0 and 3.4 μm. Their strengths are comparable to those seen in the Milky Way ISM, but follow-up observations are required in order to confirm these detections.

Geomagnetic storm is one of the most powerful factors affecting the state of the Earth’s ionosphere. Revealing the significance of formation mechanisms for ionospheric storms is still an unresolved problem. The purpose of the study is to obtain a statistical pattern of the response in regional electron content to geomagnetic storms on a global scale to interpret the results using the upper atmosphere model (the Global Self-consistent Model of the Thermosphere, Ionosphere, and Protonosphere), to make the detailed comparison with the thermospheric storm concept, and to compare the obtained pattern with results from previous statistical studies. The regional electron content is calculated based on the global ionospheric maps data, which allows us to cover the midlatitude and high-latitude zones of both hemispheres, as well as the equatorial zone. Most of the obtained statistical pattern agrees with the thermospheric storm concept and with the previous statistical studies: ionospheric responses at ionospheric storm main phases including their seasonal dependences for the high- and midlatitudes and some features of ionospheric responses at recovery phases. However, some of the statistical patterns are inconsistent with the thermospheric storm concept or contradicts the previous statistical studies: negative midlatitude ionospheric responses at recovery phases in the local winter, the domination of the spring response in the equatorial zone, seasonal features of the positive after-effects, the interhemispheric asymmetry of ionospheric responses, and the prestorm enhancement. We obtained that the contribution of electric field to the interpretation of the zonal and diurnal averaged storm-time regional electron content (REC) disturbances is insignificant. The positive after-storm effects at different latitudes are caused by n(O) disturbances.

AbstractThe results of comparing the accuracy and speed of two numerical algorithms for calculating the electric potential in the Earth’s ionosphere are presented. Several test problems for which exact analytical solutions are available are considered. It is shown that both approaches can be used to calculate the electric potential in models of the upper atmosphere, including in the regions of the equatorial electric jet. The combined use of the finite element method and the Fedorenko multigrid method with a preliminary transition to the problem for special potentials leads to a much more accurate and faster solution of the two-dimensional electrical conductivity equation in the ionosphere than the method used earlier in the block for calculating the electric potential of the global self-consistent model of the thermosphere–ionosphere–protonosphere.

AbstractAlternative scenarios for the development of world energy, based on low options for the change in the population of the planet, are being explored from the point of view of preventing dangerous global climate change. It has been shown that in order to keep the increase in the average global temperature within safe limits while maintaining the current growth rates of energy consumption and the population of the planet, a radical restructuring of the world energy industry is necessary—the “great energy transition”—with a complete rejection of the use of fossil fuels in the coming decades, which seems impossible given the inertia of development and spread of energy technologies. Using the author’s approaches to forecasting the volume and structure of world energy consumption, alternative scenarios for carbon dioxide emissions have been formed in the implementation of low, but quite realistic trends for demographic dynamics. Based on simulations of models of the global carbon cycle and climate, it is shown that the development of natural demographic processes is able to restrain growth and ensure a further decrease in the concentration of carbon dioxide in the Earth’s atmosphere, limiting the increase in the average global temperature to a completely safe level of 1.8 degrees compared to the pre-industrial period without large-scale restructuring of the world energy.

— This article examines the prospects for reducing the carbon intensity of the Russian economy and the possibility of achieving climate neutrality of the national economy by 2060. Based on the historical–extrapolation approach to the study of the development of various sociotechnical systems and by comparing them with the dynamics of carbon indicators of the economies of the world’s leading countries, it is shown that full compensation for anthropogenic greenhouse gas (GHG) emissions by absorption by the biosphere (primarily forests) is possible today only theoretically. The condition for this is the implementation of extremely ambitious large-scale programs for reforming all sectors of the national economy, from energy to forestry. Thus, in the optimistic scenario, the rate of reduction of specific indicators of GHG emissions per capita should be the maximum values achieved in the world over the past 50 years, 1% per year, and forest management should include full compensation for increasing logging and a 50% reduction in forest losses from fires, which are currently the second (after energy) source of GHG emissions into the atmosphere. The most likely scenario is one with a rate of reduction of specific GHG emissions per capita of 0.5%/year and a moderate increase in the absorption capacity of forests mainly due to the implementation of forest climate projects and a reduction in wildfire emissions. If the latter scenario is implemented, net GHG emissions could amount to approximately 700 Mt CO 2eq by 2060, which will require a national carbon capture and storage industry of unprecedented scale to achieve climate neutrality.

The prospects for reducing the carbon intensity of the Russian economy and the possibility of achieving climate neutrality of the national economy by 2060 are studied. On the basis of a historical-extrapolation approach to the study of the development of various sociotechnical systems by comparison with the dynamics of carbon indicators of the economies of the leading countries of the world, it is shown that full compensation for anthropogenic emissions of greenhouse gases (GHGs) by absorption by the biosphere (primarily forests) is theoretically possible with implementation of difficult-to-implement large-scale reform programs in all sectors of the country’s economy—from energy to forestry. Thus, in an optimistic scenario, the rate of decline in specific GHG emissions per capita should be the maximum value achieved in the world over the past 50 years at 1% per year, and forest management should include full compensation for growing deforestation and a 50% reduction in forest losses from fires, which are currently the second (after energy) source of GHG emissions into the atmosphere. The most likely scenario is one with a rate of reduction in specific GHG emissions per capita of 0.5%/year, and a significant reduction in the sinking capacity of forests to the level of 1990 due to the aging of forests and imperfect reforestation activities. Under the latter scenario, net GHG emissions by 2060 could reach 0.7 Gt CO 2eq , which would require the creation of a national industry for large-scale carbon capture and storage in order to achieve climate neutrality of the Russian economy.

AbstractThe results of the model estimate of the height of the lower limit of integration of the ratio of the concentrations of atomic oxygen and molecular nitrogen (n(O)/n(N2)) in the thermosphere according to observations using the Thermosphere, Ionosphere, and Mesosphere Energetics and Dynamics Global UltraViolet Imager (TIMED GUVI) method are presented. According to this observation technique, the lower limit of integration (h1) corresponds to the height at which the integral n(N2) takes on the value 1017 cm–2 within the range from the height of the satellite to h1. Estimates of the global self-consistent model of the thermosphere, ionosphere, and protonosphere (GSM TIP) showed that, for the conditions under consideration (January 2013 and March 2015), h1 varies in the range 148–164 km; h1 has diurnal, seasonal, latitudinal, and longitudinal variations; weakly depends on solar radiation; and significantly depends on geomagnetic activity within the above limits. To demonstrate the reproduction of the n(O)/n(N2) variations in the upper atmosphere of the Earth by the GSM TIP model, the measurements are compared with the results of the model calculations, which show their satisfactory agreement.