An anomalous subauroral red arc on 4 August, 1972: comparison of ISIS-2 satellite data with numerical calculations     

V. V. Lobzin  A. V. Pavlov  N. M. Pavlova 《Annales Geophysicae》1999,17(11):1411-1425

This study compares the Isis II satellite measurements of the electron density and temperature, the integral airglow intensity and volume emission rate at 630 nm in the SAR arc region, observed at dusk on 4 August, 1972, in the Southern Hemisphere, during the main phase of the geomagnetic storm. The model results were obtained using the time dependent one-dimensional mathematical model of the Earth’s ionosphere and plasmasphere (the IZMIRAN model). The major enhancement to the IZMIRAN model developed in this study to explain the two component 630 nm emission observed is the analytical yield spectrum approach to calculate the fluxes of precipitating electrons and the additional production rates of N⁺₂, O⁺₂, O⁺(⁴S), O⁺(²D), O⁻(²P), and O⁺(²P) ions, and O(¹D) in the SAR arc regions in the Northern and Southern Hemispheres. In order to bring the measured and modelled electron temperatures into agreement, the additional heating electron rate of 1.05 eV cm⁻³ s⁻¹ was added in the energy balance equation of electrons at altitudes above 5000 km during the main phase of the geomagnetic storm. This additional heating electron rate determines the thermally excited 630 nm emission observed. The IZMIRAN model calculates a 630 nm integral intensity above 350 km of 4.1 kR and a total 630 nm integral intensity of 8.1 kR, values which are slightly lower compared to the observed 4.7 kR and 10.6 kR. We conclude that the 630 nm emission observed can be explained considering both the soft energy electron excited component and the thermally excited component. It is found that the inclusion of N₂(v > 0) and O₂(v > 0) in the calculations of the O⁺(⁴S) loss rate improves the agreement between the calculated N_e and the data on 4 August, 1972. The N₂(v > 0) and O₂(v > 0) effects are enough to explain the electron density depression in the SAR arc F-region and above F2 peak altitude. Our calculations show that the increase in the O⁺ + N₂ rate factor due to the vibrationally excited nitrogen produces the 5–19% reductions in the calculated quiet daytime peak density and the 16–24% decrease in NmF2 in the SAR arc region. The increase in the O⁺ + N₂ loss rate due to vibrationally excited O₂ produces the 7–26% decrease in the calculated quiet daytime peak density and the 12–26% decrease in NmF2 in the SAR arc region. We evaluated the role of the electron cooling rates by low-lying electronic excitation of O₂(a¹δ_g) and O₂(b¹σ_g⁺), and rotational excitation of O₂, and found that the effect of these cooling rates on T_e can be considered negligible during the quiet and geomagnetic storm period 3–4 August, 1972. The energy exchange between electron and ion gases, the cooling rate in collisions of O(³P) with thermal electrons with excitation of O(¹D), and the electron cooling rates by vibrational excitation of O₂ and N₂ are the largest cooling rates above 200 km in the SAR arc region on 4 August, 1972. The enhanced IZMIRAN model calculates also number densities of N₂(B³π_g⁺), N₂(C³π_u), and N₂(A³σ_u⁺) at several vibrational levels, O(¹S), and the volume emission rate and integral intensity at 557.7 nm in the region between 120 and 1000 km. We found from the model that the integral integral intensity at 557.7 nm is much less than the integral intensity at 630 nm.  相似文献   

Hydrogeochemical Aspects of the Behavior of Elements at the Development of the Albynskoe Gold Field,Amur Basin     

Radomskaya  V. I.  Radomskii  S. M.  Pavlova  L. M.  Shumilova  L. P. 《Water Resources》2019,46(2):226-241

Water Resources - Сomposition of chemical elements in natural waters and rocks of the Albynskoe Gold Field have been studied to elusidate the possible environmental effects of open cast...  相似文献   

Early Mesozoic lamprophyres in Gorny Altai: petrology and age boundaries     

E.A. Vasyukova  A.E. Izokh  A.S. Borisenko  G.G. Pavlova  V.P. Sukhorukov  Tran Tuan Anh 《Russian Geology and Geophysics》2011,52(12):1574-1591

The Mesozoic Chuya dike complex was recognized by R.V. Obolenskaya based on the similar mineral composition of dikes and their age characteristics. Lamprophyres occur along the large Terekta–Tolbonur and Kurai–Kobda shear zones. The Chuya complex was studied by the example of two areas, South Chuya and Yustyd, with different levels of erosional truncation. The dikes of the first area are localized in the South Chuya Ridge, where they cut Cambrian–Ordovician metamorphic rocks, and the dikes of the Yustyd area occur in the Devonian terrigenous blackshale deposits of the Yustyd trough. The dikes of these areas differ in structures, textures, the degree of carbonatization, and mineral composition. The performed studies of rocks and minerals confirmed that the dikes of both areas belong to the same complex. They helped to establish the regularities of the lithologic composition of the entire complex and its local areas and to substantiate the recognition of areas not only from their geologic position but also by the composition, structures, and textures of rocks and their mineral composition. Geochronological data show two stages of the complex formation: 236–234 and 250–242 Ma. The results of studies also demonstrate that the lamprophyres and coeval syenites of the Tarkhata massif are fractionates of the same parental melt and can be united into a hypabyssal-plutonic complex. Comparison with other Permo-Triassic lamprophyre complexes showed that the wide variations of the composition of the Chuya rocks and its trend as well as the geochemical anomalies are specific features of complexes of high-K lamprophyres.  相似文献   

Silicate-iron fluid media in rhyolitic magma: Data on rhyolites from the Nilginskaya depression,Central Mongolia     

I. S. Peretyazhko  E. A. Savina  N. S. Karmanov  L. A. Pavlova 《Petrology》2014,22(3):255-292

Relicts of silicate-iron fluid media were found in the Early Cretaceous rhyolites of the Nilginskaya depression, Central Mongolia. They are localized in matrix cavities and in the inclusions in quartz and sanidine phenocrysts. The mineral composition of rhyolites and aggregates of silicate-iron phases has been studied. Calculations showed that crystallization of ilmenite and magnetite in a matrix occurred within a temperature range of 593–700°C and oxygen fugacity $\Delta \log f_{O_2 }$ NNO from ?2.29 to 1.68. The average compositions of the rhyolites and residual glasses in melt inclusions (MI) have A/CNK index of 1.03–1.05. The compositions of MI glasses define a trend from agpaitic to plumasitic types (A/NK and A/CNK change from 0.8–0.9 to 1.1–1.2). According to calculations, the rhyolitic melt was solidified at 640–750°C. Based on cathodoluminescent study, inclusions with silicate-iron phases are observed separately or together with MI in the early and intermediate growth zones of quartz and sanidine crystals. Aggregates found in the inclusions are represented by loose matter consisting of silica with small admixture of Al, Na, K, and Cl; silicate-iron aggregates with wide variations of Fe and Si; essentially Fe-rich micaceous and mica-silicate-iron aggregates. They usually have variable composition (wt %): 30–60 SiO₂, 10–25 Al₂O₃, 10–30 FeO, up to 3 TiO₂, 1.5–4 MgO, up to 3 CaO, up to 3 Na₂O, up to 3 K₂O, and up to 4 P₂O₅. They presumably contain up to 10–15 wt % H₂O. Some inclusions comprise large segregations of siderophyllite enriched in F (3–10 wt %) and Cl (0.1–3.3 wt %). Evolution of the rhyolitic melt from magmatic chamber to its vitrification after ejection led to the decrease of F content. The highest F content (1–1.8 wt %) is typical of MI glasses, while the lowest content (0.05–0.1 wt %) was found in the glassy matrix and rhyolitic samples. The melt degassing was accompanied by the release of F-rich fluid containing up to 1.3 wt % F (based on partition coefficient ^fluid/meltD_F) or 0.2–0.8 mol/dm³ HF (based on composition of micas from matrix and inclusions). Segregations of silicate-iron media existed in the rhyolitic magma. During formation of rhyolitic pile, these media were in a liquid state. The silicate-iron fluid media captured in MI could not be true fluids or silicate melts. They were likely formed during fluid-magmatic interaction and transformation of fluid phases of different density (vapor and liquid true solutions) that existed in a F-rich melt. The high concentrations of F and Cl and elevated alkalinity of fluids contribute their enrichment in silica and other elements, which could lead to the formation of hydrosilicate liquids. It is suggested that such liquids (gels) in dispersed (colloidal) state extracted F and many trace elements (P, Ti, Mg, Ca, REE, As, Nb, Th, and V) from surrounding rhyolitic magma.  相似文献   

High-temporal resolution multimode photospectropolarimeter     

V. L. Plokhotnichenko  G. M. Beskin  V. G. de Bur  S. V. Karpov  D. A. Bad’in  Z. V. Lyubetskaya  A. P. Lyubetskij  V. V. Pavlova 《Astrophysical Bulletin》2009,64(3):308-316

A hardware and software complex of the MANIA experiment designed to search for and study the photometric variability of astrophysical objects with a temporal resolution of 10^?6 s is described. The panoramic photospectropolarimeter uses interchangeable optical units, which allow the observations to be performed in four modes—spectroscopic, spectropolarimetric, photometric, and polarimetric. A coordinate—sensitive detector equipped with a set of microchannel plates is capable of recording flux fluctuations from objects and comparison stars simultaneously in different photometric bands and in different polarization planes. The Quantochron 4–48 data acquisition facility operating on line with a computer acquires observational data with a temporal resolution of 1microsecond. The methods of analysis of panoramic data with high temporal resolution are discussed.  相似文献   

The Arctic surface energy budget as simulated with the IPCC AR4 AOGCMs     

Asgeir Sorteberg  Vladimir Kattsov  John E. Walsh  Tatyana Pavlova 《Climate Dynamics》2007,29(2-3):131-156

Ensembles of simulations of the twentieth- and twentyfirst-century climate, performed with 20 coupled models for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment, provide the basis for an evaluation of the Arctic (70°–90°N) surface energy budget. While the various observational sources used for validation contain differences among themselves, some model biases and across-model differences emerge. For all energy budget components in the twentieth-century simulations (the 20C3M simulation), the across-model variance and the differences from observational estimates are largest in the marginal ice zone (Barents, Kara, Chukchi Seas). Both downward and upward longwave radiation at the surface are underestimated in winter by many models, and the ensenmble mean annual net surface energy loss by longwave radiation is 35 W/m², which is less than for the NCEP and ERA40 reanalyses but in line with some of the satellite estimates. Incoming solar radiation is overestimated by the models in spring and underestimated in summer and autumn. The ensemble mean annual net surface energy gain by shortwave radiation is 39 W/m², which is slightly less than for the observational based estimates, In the twentyfirst-century simulations driven by the SRES A2 scenario, increased concentrations of greenhouse gasses increase (average for 2080–2100 minus average for 1980–2000 averages) the annual average ensemble mean downward longwave radiation by 30.1 W/m². This was partly counteracted by a 10.7 W/m² reduction in downward shortwave radiation. Enhanced sea ice melt and increased surface temperatures increase the annual surface upward longwave radiation by 27.1 W/m² and reduce the upward shortwave radiation by 13.2 W/m², giving an annual net (shortwave plus longwave) surface radiation increase of 5.8 W/m² , with the maximum changes in summer. The increase in net surface radiation is largely offset by an increased energy loss of 4.4 W/m² by the turbulent fluxes.  相似文献   

SENSITIVITY OF THE RUSSIAN AGRICULTURE TO CHANGES IN CLIMATE, CO2 AND TROPOSPHERIC OZONE CONCENTRATIONS AND SOIL FERTILITY     

Oleg D. Sirotenko  Helena V. Abashina  Vera N. Pavlova 《Climatic change》1997,36(1-2):217-232

Russian agriculture sensitivity to changes in climate, soil and atmosphere chemistry were analyzed. Calculated data are presented on crop productivity of grain crops and grasses (C₃) under arid and humid scenarios of climate taking account of one-, two-, three and four-factor natural environment impacts. All four factors under studies (climatic parameters, CO₂ and tropospheric ozone concentrations, soil degradation extent) greatly impact agriculture productivity. The effect of interaction between all considered factors on agroecosystem productivity is studied. It is established that a simple additive scheme for explaining the complex effect of some factors can be much violated. In this case, not only variations in the mean crop yield levels but also variations in the degree of crop stability have been assessed in some regions, that may be more important for determining the social-economic consequences. It turned out that the recurrence of critically very low yields in steppe regions may increase two fold as a result of global warming.  相似文献   

Kombinierter Natrium- und Chloridaustausch als Vorstufe der Membranentsalzung von Wasser Sodium-Chloride Ion Exchange of Water before Membrane Demineralization     

St. Pavlova  I. Dobrevski 《洁净——土壤、空气、水》1993,21(3):173-176

The possibility of using sodium-chloride ion exchange for water pretreatment before membrane demineralization was studied. The parameters of the water obtained are: permanganate oxygen demand, lower than 1.0 mg O₂/dm³; MF_0.45, lower than 150 s; amount of total iron, lower than 50 μg/dm³. This water meets the requirements for all reverse osmosis and electrodialysis membranes.  相似文献   

Palladium (II) Biosorption by the Cell Wall of <Emphasis Type="Italic">Penicillium canescens</Emphasis>     

L.?M.?Pavlova  E.?V.?NekrasovEmail author  V.?I.?Radomskaya  L.?P.?Shumilova  N.?A.?Borodina  A.?P.?Sorokin 《Doklady Earth Sciences》2018,483(1):1442-1444

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Source Provenance and Paleogeographic Conditions during Deposition of Jurassic Continental Sediments in the Southern Part of the Siberian Platform (Implication of Sm–Nd and U–Pb Data)     

E. I. Demonterova  A. V. Ivanov  E. A. Mikheeva  A. V. Arzhannikova  A. O. Frolov  S. G. Arzhannikov  N. V. Bryanskiy  L. A. Pavlova  L. Z. Reznitskii  O. V. Zarubina 《Doklady Earth Sciences》2018,480(2):720-724

The first Sm–Nd isotopic data and U–Pb (LA–ICP–MS) detrital zircon ages from sandstones of the Prisayan and Kuda Formations (the Irkutsk Basin, southern part of the Siberian Platform) have been obtained. They demonstrate that during accumulation of the sediments in the Irkutsk Basin, the contribution of local erosion sources decreased over time, while input from the Paleo–Transbaikalia sources increased. The change in provenance areas was triggered by tectonic rebuilding in Paleo–Transbaikalia caused by the closure of the Mongol–Okhotsk Ocean.  相似文献