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Makarov V. I. Stoyanova M. N. Sivaraman K. R. 《Journal of Astrophysics and Astronomy》1982,3(4):379-382
Ring-like filaments have been detected on the spectroheliograms in the H-alpha line. Inside these filaments the magnetic field
flux has a predominant polarity. Some of the dark filaments are connected by filament channels which can be seen at the limb
either as (a) weak prominences or (b) dense low chromospheric features or (c) multi-channel system of matter flow between
two prominences or (d) common quiescent prominences. The filament and the filament channel together form a continuous closed
contour and outline the region of thef polarity particularly at the beginning of the solar cycle. The change in sign of the polar field of the Sun is associated
with the drift of the filament band to high latitudes. 相似文献
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Stéphane Reboulet Peter F. Rawson Josep A. Moreno-Bedmar Maria B. Aguirre-Urreta Ricardo Barragán Yuri Bogomolov Miguel Company Celestina González-Arreola Vyara Idakieva Stoyanova Alexander Lukeneder Bertrand Matrion Vasily Mitta Hasina Randrianaly Zdenek Vaši?ek Evgenij J. Baraboshkin Didier Bert Stéphane Bersac Tamara N. Bogdanova Luc G. Bulot Jean-Louis Latil Irina A. Mikhailova Pierre Ropolo Ottilia Szives 《Cretaceous Research》2011,32(6):786-793
The 4th Kilian Group meeting (Dijon, France, 30th August 2010) focused on the Aptian and Albian Stages. For the Aptian, a two-fold division of the stage was adopted for the Mediterranean area with a boundary between the Dufrenoyia furcata and Epicheloniceras martini Zones. The main changes to the zonal scheme concern the Lower Aptian with: the introduction of a Deshayesites luppovi Subzone in the upper part of the Deshayesites oglanlensis Zone; the replacement of Deshayesites weissi by Deshayesites forbesi as new index-species of the second interval zone; the introduction of a Roloboceras hambrovi Subzone in the upper part of the D. forbesi Zone; and the subdivision of the D. furcata Zone into the D. furcata and Dufrenoyia dufrenoyi Subzones. For the Albian, the upper part of the Douvilleiceras mammillatum Zone (Lower Albian) is now characterized by a Lyelliceras pseudolyelli Subzone. The main amendments concern the Upper Albian. The base of this substage is defined by the base of the Dipoloceras cristatum Zone. Above it, the Upper Albian zonal scheme comprises in stratigraphic order the Mortoniceras pricei, Mortoniceras inflatum, Mortoniceras fallax, Mortoniceras rostratum, Mortoniceras perinflatum and Arrhaphoceras briacensis Zones. 相似文献
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Time series analysis and forecasting for air pollution in small urban area: an SARIMA and factor analysis approach 总被引:3,自引:3,他引:0
Snezhana Georgieva Gocheva-Ilieva Atanas Valev Ivanov Desislava Stoyanova Voynikova Doychin Todorov Boyadzhiev 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(4):1045-1060
Despite the existing public and government measures for monitoring and control of air quality in Bulgaria, in many regions, including typical and most numerous small towns, air quality is not satisfactory. In this paper, factor analysis and Box–Jenkins methodology are applied to examine concentrations of primary air pollutants such as NO, NO2, NOx, PM10, SO2 and ground level O3 in the town of Blagoevgrad, Bulgaria within a 1 year period from 1st September 2011 to 31st August 2012, based on hourly measurements. By using factor analysis with PCA and Promax rotation, a high multicollinearity between the six pollutants has been detected. The pollutants were grouped in three factors and the degree of contribution of the factors to the overall pollution was determined. This was interpreted as the presence of common sources of pollution. The main part of the study involves the performance of time series analysis and the development of univariate stochastic seasonal autoregressive integrated moving average (ARIMA) models with recording on a hourly basis as seasonality. The study also incorporates the Yeo–Johnson power transformation for variance stabilizing of the data and model selection by using Bayersian information criterion. The obtained SARIMA models demonstrated very good fitting performance with regard to the observed air pollutants and short-term predictions for 72 h ahead, in particular in the case of ozone and particulate matter PM10. The presented statistical approaches allow the building of non-complex models, effective for short-term air pollution forecasting and useful for advance warning purposes in urban areas. 相似文献
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M. N. Stoyanova 《Solar physics》1970,15(2):349-355
A new spectroscopic method of deriving the three-dimensional information (escalation) worked out at the Pulkovo Observatory was applied to observations of solar faculae. The size of the investigated area was 70 × 18. Two series of spectra were obtained simultaneously in four spectral regions (H, D1,2, (Nai), H, and H, K (Caii)) with a quadruple-camera spectrograph attached to the second horizontal solar telescope at Pulkovo on 13 August, 1968.It was found from the analysis of the maps of brightness distribution in the cores of the lines and continuum that the facular emission lies in ropes which incline to the solar surface. 相似文献
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The photospheric, chromospheric, and magnetic field structure of large active region No. 18474 of July 1982 are studied. Various morphological features observed are described and their possible role in the evolution of sunspots group discussed. The abundance of different light bridges is a characteristic feature for this group. It is shown that the light bridges in the photosphere coincide with the location and direction of arch filaments or fibril streams in the chromosphere, and appear in the region of a developing rotating magnetic field. 相似文献
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