The Gradual Phase of the X17 Flare on October 28, 2003     

G. Del Zanna  B. Schmieder  H. Mason  A. Berlicki  S. Bradshaw 《Solar physics》2006,239(1-2):173-191

We present SOHO/CDS observations taken during the gradual phase of the X17 flare that occurred on October 28, 2003. The CDS data are supplemented with TRACE and ground-based observations. The spectral observations allow us to determine velocities from the Doppler shifts measured in the flare loops and in the two ribbon kernels, one hour and a half after the flare peak. Strong downflows (>70 km s⁻¹) are observed along the loop legs at transition-region temperatures. The velocities are close to those expected for free fall. Observations and results from a hydrodynamic simulation are consistent with the heating taking place for a short time near the top of the arcade. Slight upflows are observed in the outer edges of the ribbons (<60 km s⁻¹) in the EUV lines formed at log T < 6.3. These flows could correspond to the so-called “gentle evaporation.” At “flare” temperatures (Fe xix, log T = 6.9), no appreciable flows are observed. The observations are consistent with the general standard reconnection models for two-ribbons flares.  相似文献   

Material ejecta in a disturbed solar filament     

M. A. Raadu  J. M. Malherbe  B. Schmieder  P. Mein 《Solar physics》1971,109(1):59-79

H observations, using the Multichannel Subtractive Double Pass (MSDP) spectrograph operating on the Meudon Solar Tower, have been made of an active region filament which undergoes a disparition brusque. The period of observation was from 10 45 to 13 30 UT on 22 June, 1981. Velocity and intensity fluctuations in H were measured. The proper motions of ejecta were followed allowing their trajectories and vector velocities to be determined. To model the dynamics of ejecta several models using thermal or magnetic driving forces are compared. The most promising model explains the motion as the consequence of magnetic stresses acting on an isolated magnetized plasmoïd in a diverging flux tube.  相似文献   

Implementing Europe's climate targets at the regional level     

Brigitte Wolkinger  Andrea Damm  Stefan Schleicher  Andreas Tuerk  Wolf Grossman 《Climate Policy》2013,13(6):667-689

Having agreed upon a binding emissions reduction path by 2020, the EU plays a leading role in international climate policy. The EU currently pursues a dual approach through an Emissions Trading Scheme (ETS) at the EU level and also via national targets in sectors not covered by the ETS. The latter include the buildings sector, transportation, agriculture, and waste. Emissions from these sectors are mainly subject to policies at provincial and local levels. A method is presented for elaborating and implementing a long-term climate policy process up to 2030 for the regional (provincial) level. Building on regional GHG inventory data, a set of indicators for each sector is developed in order to arrive at a target path consistent with the deduced regional GHG reduction requirement. Policy measures and their implementation are then settled subsequent to this process. Quantitative regional targets are found to be a prerequisite for the formation of regional climate policy as they increase participant responsibility and commitment. A five-step process of stakeholder participation ensures effective implementation of regional climate action plans. Insights from an exemplary European region are drawn upon, and policy issues are discussed in both quantitative and institutional terms.  相似文献   

BAM‐S005 Type A and B: New Silicate Reference Glasses for Microanalysis     

Qi‐Chao Yang  Klaus Peter Jochum  Brigitte Stoll  Ulrike Weis  Dmitry Kuzmin  Michael Wiedenbeck  Heike Traub  Meinrat O. Andreae 《Geostandards and Geoanalytical Research》2012,36(3):301-313

To test whether the silicate reference glasses BAM‐S005‐A and BAM‐S005‐B from BAM (The Federal Institute for Materials Research and Testing, Germany) are suitable materials for microanalysis, we investigated the homogeneity of these reference glasses using the microanalytical techniques EPMA, LA‐ICP‐MS and SIMS. Our study indicated that all major and most trace elements are homogeneously distributed at micrometre sampling scale in both types of glass. However, some trace elements (e.g., Cs, Cl, Cr, Mo and Ni) seem to be inhomogeneously distributed. We also determined the composition of BAM‐S005‐A and BAM‐S005‐B. The EPMA data of major elements confirmed the information values specified by the certificate. With the exception of Sr, Ba, Ce and Pb, our trace element data by LA‐ICP‐MS were also in agreement with the certified values within the stated uncertainty limits. The reasons for the discrepancy in these four elements are still unclear. In addition, we report new data for twenty‐two further trace elements, for which the concentrations were not certified. Based on our investigation, we suggest that both of these materials are suitable for many microanalytical applications.  相似文献   

Magnetic Causes of the Eruption of a Quiescent Filament   总被引：1，自引：0，他引：1  

B. Schmieder  V. Bommier  R. Kitai  T. Matsumoto  T. T. Ishii  M. Hagino  H. Li  L. Golub 《Solar physics》2008,247(2):321-333

During the JOP178 campaign in August 2006, we observed the disappearance of our target, a large quiescent filament located at S25°, after an observation time of three days (24 August to 26 August). Multi-wavelength instruments were operating: THEMIS/MTR (“MulTi-Raies”) vector magnetograph, TRACE (“Transition Region and Coronal Explorer”) at 171 Å and 1600 Å and Hida Domeless Solar telescope. Counter-streaming flows (+/?10 km?s^?1) in the filament were detected more than 24 hours before its eruption. A slow rise of the global structure started during this time period with a velocity estimated to be of the order of 1 km?s^?1. During the hour before the eruption (26 August around 09:00 UT) the velocity reached 5 km?s^?1. The filament eruption is suspected to be responsible for a slow CME observed by LASCO around 21:00 UT on 26 August. No brightening in Hα or in coronal lines, no new emerging polarities in the filament channel, even with the high polarimetry sensitivity of THEMIS, were detected. We measured a relatively large decrease of the photospheric magnetic field strength of the network (from 400 G to 100 G), whose downward magnetic tension provides stability to the underlying stressed filament magnetic fields. According to some MHD models based on turbulent photospheric diffusion, this gentle decrease of magnetic strength (the tension) could act as the destabilizing mechanism which first leads to the slow filament rise and its fast eruption.  相似文献   

Study of an Extended EUV Filament Using SoHO/SUMER Observations of the Hydrogen Lyman Lines     

P. Schwartz  B. Schmieder  P. Heinzel  P. Kotr? 《Solar physics》2012,281(2):707-728

A?filament and its channel close to the solar disk were observed in the complete hydrogen Lyman spectrum, and in several EUV lines by the SUMER (Solar Ultraviolet Measurement of Emitted Radiation) and CDS (Coronal Diagnostic Spectrometer) spectrographs on the SoHO satellite, and in H?? by ground-based telescopes during a multi-instrument campaign in May 2005. It was a good opportunity to get an overview of the volume and the density of the cold plasma in the filament channel; these are essential parameters for coronal mass ejections. We found that the width of the filament depends on the wavelength in which the filament is observed (around 15?arcsec in H??, 30?arcsec in L??, and 60?arcsec in EUV). In L?? the filament is wider than in H?? because cool plasma, not visible in H??, is optically thick at the L?? line center, and its presence blocks the coronal emission. We have derived physical plasma properties of this filament fitting the Lyman spectra and H?? profiles by using a 1D isobaric NLTE model. The vertical temperature profile of the filament slab is flat (T??7000?K) with an increase to ???20?000?K at the top and the bottom of the slab. From an analysis of the L?? and H?? source functions we have concluded that these lines are formed over the whole filament slab. We have estimated the geometrical filling factor in the filament channel. Its low value indicates the presence of multi-threads.  相似文献   

The Preparation and Preliminary Characterisation of Three Synthetic Andesite Reference Glass Materials (ARM‐1, ARM‐2, ARM‐3) for In Situ Microanalysis     

Shitou Wu  Gerhard Wrner  Klaus Peter Jochum  Brigitte Stoll  Klaus Simon  Andreas Kronz 《Geostandards and Geoanalytical Research》2019,43(4):567-584

Three synthetic reference glasses were prepared by directly fusing and stirring 3.8 kg of high‐purity oxide powders to provide reference materials for microanalytical work. These glasses have andesitic major compositions and are doped with fifty‐four trace elements in nearly identical abundance (500, 50, 5 µg g^?1) using oxide powders or element solutions, and are named ARM‐1, 2 and 3, respectively. We further document that sector‐field (SF) ICP‐MS (Element 2 or Element XR) is capable of sweeping seventy‐seven isotopes (from ⁷Li to ²³⁸U, a total of sixty‐eight elements) in 1 s and, thus, is able to quantify up to sixty‐eight elements by laser sampling. Micro‐ and bulk analyses indicate that the glasses are homogeneous with respect to major and trace elements. This paper provides preliminary data for the ARM glasses using a variety of analytical techniques (EPMA, XRF, ICP‐OES, ICP‐MS, LA‐Q‐ICP‐MS and LA‐SF‐ICP‐MS) performed in ten laboratories. Discrepancies in the data of V, Cr, Ni and Tl exist, mainly caused by analytical limitations. Preliminary reference and information values for fifty‐six elements were calculated with uncertainties [2 relative standard error (RSE)] estimated in the range of 1–20%.  相似文献   

Geostandards and Geoanalytical Research Bibliographic Review 2016          下载免费PDF全文

Ulrike Weis  Beate Schwager  Brigitte Stoll  Uwe Nohl  Patricia Karlowski  Isabelle Leisgang  Florentine Zwillich  Klaus Peter Jochum 《Geostandards and Geoanalytical Research》2017,41(4):487-491

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Historical analysis (2000-2005) of the coastal water quality in San Andrés Island, SeaFlower Biosphere Reserve, Caribbean Colombia     

Brigitte Gavio  Shelly Palmer-Cantillo  J. Ernesto Mancera 《Marine pollution bulletin》2010,60(7):1018-1030

To understand the coastal water quality of San Andrès Island, and provide tools for the management of its marine resources, we present the historical analysis of the island monitoring, which includes ammonia, nitrites, nitrate, phosphates, fecal and total coliforms. The anthropogenic pressure on the coastal system is heavy, with water nutrification, posing at risk seagrass and coral ecosystems. During dry season, biologically available nitrogen is 3-9 times higher than the maximum recommended for coral reefs, while during wet season values are 2-6.4 times the maximum. Biologically available phosphorous is also high, 1-8 times the maximum during dry season, 2-13 times during wet season. In some sites the concentration of pathogenic bacteria is above the limits set by law for primary and secondary contact. It is urgent to improve the management of sewage discharge, the main polluting source of San Andres coastal waters.  相似文献   

On the repeatability and consistency of three-component ambient vibration array measurements   总被引：1，自引：0，他引：1  

Brigitte Endrun  Matthias Ohrnberger  Alexandros Savvaidis 《Bulletin of Earthquake Engineering》2010,8(3):535-570

Ambient vibration measurements with small, temporary arrays that produce estimates of surface wave dispersion have become increasingly popular as a low-cost, non-invasive tool for site characterisation. An important requirement for these measurements to be meaningful, however, is the temporal consistency and repeatability of the resulting dispersion and spatial autocorrelation curve estimates. Data acquired within several European research projects (NERIES task JRA4, SESAME, and other multinational experiments) offer the chance to investigate the variability of the derived data products. The dataset analysed here consists of repeated array measurements, with several years of time elapsed between them. The measurements were conducted by different groups in different seasons, using different instrumentations and array layouts, at six sites in Greece and Italy. Ambient vibration amplitude spectra and locations of dominant sources vary between the two measurements at each location. Still, analysis indicates that this does not influence the derived dispersion information, which is stable in time and neither influenced by the instrumentation nor the analyst. The frequency range over which the dispersion curves and spatial autocorrelation curves can be reliably estimated depends on the array dimensions (minimum and maximum aperture) used in the specific deployment, though, and may accordingly vary between the repeated experiments. The relative contribution of Rayleigh and Love waves to the wavefield can likewise change between repeated measurements. The observed relative contribution of Rayleigh waves is generally at or below 50%, with especially low values for the rural sites. Besides, the visibility of higher modes depends on the noise wavefield conditions. The similarity of the dispersion and autocorrelation curves measured at each site indicates that the curves are stable, mainly determined by the sub-surface structure, and can thus be used to derive velocity information with depth. Differences between velocity models for the same site derived from independently determined dispersion and autocorrelation curves—as observed in other studies—are consequently not adequately explained by uncertainties in the measurement part.  相似文献