排序方式: 共有6条查询结果,搜索用时 31 毫秒
1
1.
M. L. Mays O. C. St. Cyr E. Quémerais S. Ferron J.-L. Bertaux S. Yashiro R. Howard 《Solar physics》2007,241(1):113-125
In this study, the possibility that coronal mass ejections (CMEs) may be observed in neutral Lyman-α emission was investigated.
An observing campaign was initiated for SWAN (Solar Wind ANisotropies), a Lyman-α scanning photometer on board the Solar and
Heliospheric Observatory (SOHO) dedicated to monitoring the latitude distribution of the solar wind from its imprints on the
interstellar sky background. This was part of SOHO Joint Observing Program (JOP) 159 and was an exploratory investigation
as it was not known how, or even if, CMEs interact with the solar wind and interstellar neutral hydrogen at this distance
(≈60 and 120 R
S). The study addresses the lack of methods for tracking CMEs beyond the field-of-view of current coronagraphs (30 R
S). In our first method we used LASCO, white-light coronagraphs on SOHO, and EIT, an extreme ultraviolet imaging telescope
also on SOHO, to identify CME candidates which, subject to certain criteria, should have been observable in SWAN. The criteria
included SWAN observation time and location, CME position angle, and extrapolated speed. None of the CME candidates that we
discuss were identified in the SWAN data. For our second method we analyzed all of the SWAN data for 184 runs of the observing
campaign, and this has yielded one candidate CME detection. The candidate CME appears as a dimming of the background Lyman-α
intensity representing ≈10% of the original intensity, moving radially away from the Sun. Multiple candidate CMEs observed
by LASCO and EIT were found which may have caused this dimming. Here we discuss the campaign, data analysis technique and
statistics, and the results. 相似文献
2.
Matthias Braun Jefferson Cardia Sim“非汉字符号”es N.Blindow Steffen Vogt U.F.Bremer M.Pfender H.Saurer F.E.Aquino F.A.Ferron 《地球空间信息科学学报》2001,4(2):47-51
1 IntroductionAtpresent,KingGeorgeIsland (KGI)isoneofthemostfrequentedsitesinAntarctica .Intotal,9permanentresearchstationsareinoperationandseveralresearchcabinshavebeenconstructed .DuetotheeasyaccessviatheChileanairstripthenum beroftheisland’sinhabitantsr… 相似文献
3.
A GIS FOR THE ANTARCTIC SPECIALLY MANAGED AREA OF ADMIRALTY BAY,KING GEORGE ISLAND,ANTARCTICA 总被引:1,自引:0,他引:1
Jefferson Cardia Sim“非汉字符号”es F.A.Ferron Matthias Braun J.Arigony Neto F.E.Aquino 《地球空间信息科学学报》2001,4(2):8-14
1 IntroductionKingGeorgeIsland’s (KGI)ecosystemshavebeensubjectedtovarioustypesofexploitationandobjectofseveralscientificexpeditions,sinceitwasdiscoveredjustafterthefirstsightingofAntarctilandbyWilliamSmithin1 81 9.KGIwasnamedaf tertheBritishkingofthattime … 相似文献
4.
Pascale Bouruet-Aubertot Yannis Cuypers Bruno Ferron Denis Dausse Olivier Ménage Agus Atmadipoera Indra Jaya 《Ocean Dynamics》2018,68(7):779-800
Microstructure measurements were performed along two sections through the Halmahera Sea and the Ombai Strait and at a station in the deep Banda Sea. Contrasting dissipation rates (??) and vertical eddy diffusivities (K z ) were obtained with depth-averaged ranges of \(\sim [9 \times 10^{-10}-10^{-5}]\) W kg??1 and of \(\sim [1 \times 10^{-5}-2 \times 10^{-3}]\) m2 s??1, respectively. Similarly, turbulence intensity, \(I={\epsilon }/(\nu N^{2})\) with ν the kinematic viscosity and N the buoyancy frequency, was found to vary seven orders of magnitude with values up to \(10^{7}\). These large ranges of variations were correlated with the internal tide energy level, which highlights the contrast between regions close and far from internal tide generations. Finescale parameterizations of ?? induced by the breaking of weakly nonlinear internal waves were only relevant in regions located far from any generation area (“far field”), at the deep Banda Sea station. Closer to generation areas, at the “intermediate field” station of the Halmahera Sea, a modified formulation of MacKinnon and Gregg (2005) was validated for moderately turbulent regimes with 100 < I < 1000. Near generation areas marked by strong turbulent regimes such as “near field” stations within strait and passages, ?? is most adequately inferred from horizontal velocities provided that part of the inertial subrange is resolved, according to Kolmogorov scaling. 相似文献
5.
Vladoiu Anda Bouruet-Aubertot Pascale Cuypers Yannis Ferron Bruno Schroeder Katrin Borghini Mireno Leizour Stephane Ismail Sana Ben 《Ocean Dynamics》2019,69(7):787-807
Ocean Dynamics - The dissipation flux coefficient, a measure of the mixing efficiency of a turbulent flow, was computed from microstructure measurements collected with a vertical microstructure... 相似文献
6.
J. Maximino T.M. Ferron Artur C. Bastos Neto Evandro F. Lima Lauro V.S. Nardi Hilton T. Costi Ronaldo Pierosan Maurício Prado 《Journal of South American Earth Sciences》2010,29(2):483-497
This paper presents geochemical, petrographic, and geochronological data on the Uatumã magmatism in the Pitinga Province, where it is represented by volcanic rocks from the Iricoumé Group and granitic rocks from the Mapuera Suite. The Iricoumé Group (1.89–1.88 Ga) is constituted of the Divisor Formation (intermediate volcanic rocks), Ouro Preto Formation (acid effusive rocks), and Paraiso Formation (acid crystal-rich ignimbrites, surge deposits, and basic rocks). The volcanic sequence is intruded by granitoids from the Mapuera Suite (1.88 Ga), mainly represented by monzogranites and syenogranites. Structural and field relations suggest that caldera complex collapse controlled the emplacement of volcanics and granitoids of the Mapuera Suite. Subsequent structure reactivations allowed the younger Madeira Suite (1.82–1.81 Ga) to be emplaced in the central portion of the caldera complex. The felsic Iricoumé magmatism is mainly composed of rhyolites, trachydacites and latites, with SiO2 contents between 64 wt% and 80 wt%. The plutonic rocks from the Mapuera Suite present SiO2 between 65 wt% and 77 wt%. Volcanic and granitic rocks present identical geochemical characteristics and that is attributed to their co-magmatic character. The felsic volcanic rocks and granites are metaluminous to slightly peraluminous and show affinity with silica-saturated alkaline series or with A-type magmas. They have Na2O + K2O between 6.6% and 10.4%, FeOt/(FeOt + MgO) varying between 0.76 and 0.99, Ga/Al ratios between 1.5 and 4.9, like typical A-type rocks; and plot in the within-plate or post-collisional fields in the (Nb + Y) vs. Rb diagram. The Nb/Y ratios indicate that these rocks are comparable to A2-type granites. This magmatism can be related to the (i) potassic alkaline series, with low Sr content in the felsic rocks explained by plagioclase fractionation at low pressure and high temperature or, alternatively, (ii) a bimodal association where magma had high crustal influence. The similarity of the Iricoumé felsic magmatism with A2-type granitoids and their high ETRL/Nb ratios suggest its relation with mantle sources previously modified by subduction, probably in a post-collision environment. Alternatively, this can be interpreted as bimodal within-plate magmatism with contamination by crustal melts. In this context, the extreme F, Nb and Zr enrichment of Madeira Suite could be explained by the presence of a thin crust which favored the presence and continuity of convective systems in the upper mantle. 相似文献
1