This paper presents a result of model calculation of the disturbance dynamo electric field, prompt penetration, overshielding and their ionospheric effects during geomagnetic storm on December 14–15, ...2006. The calculations were carried out with use of the Global Self-Consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP model) developed in WD IZMIRAN. Simulations were performed for quiet and disturbed conditions with took into account the magnetospheric convection electric field with and without took into account dynamo electric field. It has allowed to neglecting thermospheric and ionospheric effects of the disturbance dynamo electric field. The analysis of model calculation results was carried out. We have made conclusions about the role of the disturbance dynamo electric field, prompt penetration electric field and overshielding effects in thermospheic and ionospheric parameters during geomagnetic storm.
► This study presents the ionospheric effects of DDEF, PPEF and overshielding. ► Dynamo electric field, DDEF and PPEF lead to the EIA intensification. ► The DDEF leads to increase in Te during storm recovery phase. ► DDEF leads to more pronounce additional layers over F2 peak at equatorial latitudes. ► PPEF and overshielding occur in active and recovery phases of storm, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper presents a study of mesosphere and low thermosphere influence on ionospheric disturbances during 2009 major sudden stratospheric warming (SSW) event. This period was characterized by ...extremely low solar and geomagnetic activity. The study was performed using two first principal models: thermosphere‐ionosphere‐mesosphere electrodynamics general circulation model (TIME‐GCM) and global self‐consistent model of thermosphere, ionosphere, and protonosphere (GSM TIP). The stratospheric anomalies during SSW event were modeled by specifying the temperature and density perturbations at the lower boundary of the TIME‐GCM (30 km altitude) according to data from European Centre for Medium‐Range Weather Forecasts. Then TIME‐GCM output at 80 km was used as lower boundary conditions for driving GSM TIP model runs. We compare models' results with ground‐based ionospheric data at low latitudes obtained by GPS receivers in the American longitudinal sector. GSM TIP simulation predicts the occurrence of the quasi‐wave vertical structure in neutral temperature disturbances at 80–200 km altitude, and the positive and negative disturbances in total electron content at low latitude during the 2009 SSW event. According to our model results the formation mechanisms of the low‐latitude ionospheric response are the disturbances in the n(O)/n(N2) ratio and thermospheric wind. The change in zonal electric field is key mechanism driving the ionospheric response at low latitudes, but our model results do not completely reproduce the variability in zonal electric fields (vertical plasma drift) at low latitudes.
Key Points
Current study combines GSM TIP model with NCAR TIME‐GSM driven by ECMWF data
O/N2 and thermospheric wind contribute to ionospheric variations during SSW
Vertical ion drift plays the primary role in TEC disturbances during SSW
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We present a comparative analysis of first principles Global Self‐consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP) in prediction of ionospheric disturbances during three ...geomagnetic storms: from moderate on 8–9 March 2008 and on 17–18 March 2013 to strong one on 17–18 March 2015, so‐called St. Patrick's Day storms. We have found that in general, the GSM TIP model gave reasonable prediction of both positive and negative ionospheric storms. Most difficulties have been found for the St. Patrick's Day storms. Namely, a strong positive storm at low latitudes above the Pacific and in the South Atlantic Anomaly region on the main and recovery phases could not be predicted by the model. The positive storm could be explained by ionization effect of energetic electron enhancements. Dynamics of negative ionospheric storms at middle latitudes was predicted by the GSM TIP model quite well though the amplitude of storms was underestimated. The latter could result from underestimation of the N2 contribution especially under unusual conditions of anomalous expansion of auroral precipitations to middle latitudes during the 2015 St. Patrick's Day storm.
Key Points
Ionospheric dynamics was modeled for St. Patrick's Day magnetic storms
The storms could be predicted well with some important exceptions
The exceptions are due to anomalous expansion of the auroral oval and effects of energetic particles
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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.
We studied the contribution of the global plasmaspheric and ionospheric electron content (PEC and IEC) into total electron content (TEC). The experimental PEC was estimated by comparison of GPS TEC ...observations and FORMOSAT-3/COSMIC radio occultation IEC measurements. Results are retrieved for the winter solstice (January and December 2009) conditions. Global maps of COSMIC-derived IEC, PEC and GPS TEC were compared with Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP) results. In addition, we used GSM TIP model results in order to estimate the contribution of plasmaspheric electron content into TEC value at the different altitudinal regions. The advantages and problems of the outer ionospheric/plasmaspheric parameters (O+/H+ transition height, TEC and electron density at height above F2 layer peak) representation by the IRI (International Reference Ionosphere) model are discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper presents a study of thermospheric and ionospheric response to the 2008 minor sudden stratospheric warming (SSW) event. This period was characterized by low solar and geomagnetic activity. ...The study was performed using the Global Self‐consistent Model of Thermosphere, Ionosphere, and Protonosphere (GSM TIP). Model results were compared with ionosonde data from Irkutsk, Kaliningrad, Sao Jose dos Campos, and Jicamarca. The SSW event was modeled by specifying the temperature and density perturbations at the lower boundary of the GSM TIP (80 km altitude). GSM TIP simulation allowed the reproduction of the lower thermosphere temperature disturbances (the occurrence of the quasi‐wave 1 structure at 80–130 km altitude with a vertical scale of ∼40 km), the negative response of F2 region electron density and the positive response of electron temperature at 300 km during the 2008 minor SSW event. The main formation mechanism of the global ionospheric response is due to the disturbances (decrease) in then(O)/n(N2) ratio. The change in zonal electric field is another important mechanism of the ionospheric response at low latitudes.
Key Points
We present model evidence of global negative foF2 disturbances during SSW
Decreases in n(O)/n(N2) and westward electric field occur during SSW
During SSW and mesospheric cooling a lower thermospheric warming is detected
This study presents an analysis of the ground-based observations and model simulations of ionospheric electron density disturbances at three longitudinal sectors (eastern European, Siberian and ...American) during geomagnetic storms that occurred on 26–30 September 2011. We use the Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP) to reveal the main mechanisms influencing the storm-time behavior of the total electron content (TEC) and the ionospheric F2 peak critical frequency (foF2) during different phases of geomagnetic storms. During the storm's main phase the long-lasting positive disturbances in TEC and foF2 at sunlit mid-latitudes are mainly explained by the storm-time equatorward neutral wind. The effects of eastward electric field can only explain the positive ionospheric storm in the first few hours of the initial storm phase. During the main phase the ionosphere was more changeable than the plasmasphere. The positive disturbances in the electron content at the plasmaspheric heights (800–20 000 km) at high latitudes can appear simultaneously with the negative disturbances in TEC and foF2. The daytime positive disturbances in foF2 and TEC occurred at middle and low latitudes and at the Equator due to n(O) ∕ n(N2) enhancement during later stage of the main phase and during the recovery phase of the geomagnetic storm. The plasma tube diffusional depletion and negative disturbances in electron and neutral temperature were the main formation mechanisms of the simultaneous formation of the positive disturbances in foF2 and negative disturbances in TEC at low latitudes during the storm's recovery phase.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The prospects for reducing the carbon intensity of the Russian economy and the possibility of achieving climate neutrality of the country’s national economy by 2060 are examined. Based on a ...historical-extrapolation approach to the study of the development of various socio-technical systems and by comparing the dynamics of carbon indicators of the economies of Russia and the leading countries of the world, it is shown that full compensation of anthropogenic greenhouse gases emissions when absorbed by the biosphere (primarily forests) is today rather only theoretically possible. The condition for this is the implementation of extremely ambitious large-scale reform programs in all sectors of the Russian economy, from energy to forestry. Thus, in an optimistic scenario, the decline rate of specific indicators of greenhouse gas emissions per capita should have the maximum values achieved in the world over the last 50 years, i.e. 1%/year. Forest management must include full compensation for increasing deforestation and a 50% reduction in forest losses from fires, which are currently the second (after energy) source of greenhouse gas emissions into the atmosphere. The most likely scenario is one in which the decline rate of specific greenhouse gas emissions per capita is 0.5%/year and a moderate increase in the absorption capacity of forests is ensured, mainly due to the implementation of forest climate projects and a reduction in wildfire emissions. If the latter scenario is implemented, net greenhouse gas emissions could amount to approximately 700 Mt CO
2
(equiv.) by 2060, which will require the nation’s carbon capture and storage industry on an unprecedented scale to achieve climate neutrality.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
ABSTRACT
We present a comprehensive study of the excitation of C i fine-structure levels along 57 sight lines in the Large and Small Magellanic Clouds (LMC and SMC). The sightlines were selected by ...the detection of H2 in FUSE spectra. Using archival HST/COS and HST/STIS spectra, we detected absorption of C i fine-structure levels and measured their populations for 29 and 28 sightlines in the LMC and SMC, respectively. The C i column density ranges from 1013 to $10^{14}\, {\rm cm}^{-2}$ for the LMC and 1013 to $10^{15.4}\, {\rm cm}^{-2}$ for the SMC. We found excitation of C i fine-structure levels in the LMC and SMC to be 2–3 times higher than typical values in local diffuse interstellar medium (ISM). Comparing excitation of both C i fine-structure levels and H2 rotational levels with a grid of PDR Meudon models, we find that neutral cold gas in the LMC and SMC is illuminated by a stronger UV field than in local ISM ($\chi =5^{+7}_{-3}$ units of Mathis field for the LMC and $2^{+4}_{-1}$ for the SMC) and has on average higher thermal pressure (log p/k = 4.2 ± 0.4 and 4.3 ± 0.5, respectively). Magellanic Clouds sight lines likely probe regions near star-formation sites, which also affects the thermal state and C i/H2 relative abundances. At the same time, obtained enhanced UV field is consistent with some measurements at high redshifts. Together with low metallicities, this make Magellanic Clouds an interesting test case to study the central parts of high redshift galaxies.
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