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  • Space Sciences (General)  (3)
  • Polymer and Materials Science  (2)
  • 1
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    Community-wide Validation of Geospace Model Ground Magnetic Field Perturbation Predictions to Support Model Transition to Operations (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In this paper we continue the community-wide rigorous modern space weather model validation efforts carried out within GEM, CEDAR and SHINE programs. In this particular effort, in coordination among the Community Coordinated Modeling Center (CCMC), NOAA Space Weather Prediction Center (SWPC), modelers, and science community, we focus on studying the models' capability to reproduce observed ground magnetic field fluctuations, which are closely related to geomagnetically induced current phenomenon. One of the primary motivations of the work is to support NOAA SWPC in their selection of the next numerical model that will be transitioned into operations. Six geomagnetic events and 12 geomagnetic observatories were selected for validation.While modeled and observed magnetic field time series are available for all 12 stations, the primary metrics analysis is based on six stations that were selected to represent the high-latitude and mid-latitude locations. Events-based analysis and the corresponding contingency tables were built for each event and each station. The elements in the contingency table were then used to calculate Probability of Detection (POD), Probability of False Detection (POFD) and Heidke Skill Score (HSS) for rigorous quantification of the models' performance. In this paper the summary results of the metrics analyses are reported in terms of POD, POFD and HSS. More detailed analyses can be carried out using the event by event contingency tables provided as an online appendix. An online interface built at CCMC and described in the supporting information is also available for more detailed time series analyses.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN15054 , Space Weather; 11; 6; 369-385
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Geospace Environment Modeling 2008-2009 Challenge: Ground Magnetic Field Perturbations (2011)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Acquiring quantitative metrics!based knowledge about the performance of various space physics modeling approaches is central for the space weather community. Quantification of the performance helps the users of the modeling products to better understand the capabilities of the models and to choose the approach that best suits their specific needs. Further, metrics!based analyses are important for addressing the differences between various modeling approaches and for measuring and guiding the progress in the field. In this paper, the metrics!based results of the ground magnetic field perturbation part of the Geospace Environment Modeling 2008 2009 Challenge are reported. Predictions made by 14 different models, including an ensemble model, are compared to geomagnetic observatory recordings from 12 different northern hemispheric locations. Five different metrics are used to quantify the model performances for four storm events. It is shown that the ranking of the models is strongly dependent on the type of metric used to evaluate the model performance. None of the models rank near or at the top systematically for all used metrics. Consequently, one cannot pick the absolute winner : the choice for the best model depends on the characteristics of the signal one is interested in. Model performances vary also from event to event. This is particularly clear for root!mean!square difference and utility metric!based analyses. Further, analyses indicate that for some of the models, increasing the global magnetohydrodynamic model spatial resolution and the inclusion of the ring current dynamics improve the models capability to generate more realistic ground magnetic field fluctuations.
    Keywords: Space Sciences (General)
    Type: GSFC.JA.00421.2012 , Space Weather; 9
    Format: text
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    NASA TECHNICAL REPORTS
  • 3
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    Community-Wide Validation of Geospace Model Local K-Index Predictions to Support Model Transition to Operations (2016)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: We present the latest result of a community-wide space weather model validation effort coordinated among the Community Coordinated Modeling Center (CCMC), NOAA Space Weather Prediction Center (SWPC), model developers, and the broader science community. Validation of geospace models is a critical activity for both building confidence in the science results produced by the models and in assessing the suitability of the models for transition to operations. Indeed, a primary motivation of this work is supporting NOAA/SWPCs effort to select a model or models to be transitioned into operations. Our validation efforts focus on the ability of the models to reproduce a regional index of geomagnetic disturbance, the local K-index. Our analysis includes six events representing a range of geomagnetic activity conditions and six geomagnetic observatories representing midlatitude and high-latitude locations. Contingency tables, skill scores, and distribution metrics are used for the quantitative analysis of model performance. We consider model performance on an event-by-event basis, aggregated over events, at specific station locations, and separated into high-latitude and midlatitude domains. A summary of results is presented in this report, and an online tool for detailed analysis is available at the CCMC.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN40879 , Space Weather (ISSN 1542-7390) (e-ISSN 1542-7390); 14; 7; 469-480
    Format: text
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    NASA TECHNICAL REPORTS
  • 4
    Electronic Resource
    Electronic Resource
    Copolymerisation von Butadien/Styrol mit anionischen Emulgatoren (1979)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 30 (1979), S. 194-198 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Investigations on the effect of the structure of some important anionic emulsifiers of the carboxyl, sulfat and sulfonate series on the emulsion polymerization of butadiene with styrene are described. The overall reaction rate vBr of emulsion copolymerization is differently affected by these compounds in dependence on the chain length of the alkyl or alkylaryl groups. This effect shows particularly in the stage of particle formation. Further effects on the decomposition of potassium peroxide disulfate caused by carboxyl, sulfate and sulfonate groups were found. No effect of the number of C atoms in the alkyl chain of carboxylic acid salts (C12—C18) was detected.
    Notes: Es werden Untersuchungen über den Einfluß der Struktur einiger wichtiger anionischer Emulgatoren der Carboxyl-Sulfat- und Sulfonatreihe auf die Emulsionscopolymerisation von Butadien/Styrol mitgeteilt. Die Verbindungen üben, in Abhängigkeit von der Kettenlänge ihres Alkyl- bzw. Alkylarylrestes, einen unterschiedlichen Einfluß auf die Bruttoreaktionsgeschwindigkeit vBr der Emulsionscopolymerisation aus. Dieser Einfluß zeigt sich besonders in der Teilchenbildungsperiode. Es wurden weiterhin Einflüsse auf den Kaliumperoxodisulfatzerfall in Abhängigkeit von der Carboxyl-, Sulfat- bzw. Sulfonatgruppe gefunden. Ein Einfluß der C-Atomzahl in der Alkylkette von Carbonsäuresalzen (C12—C18) war nicht zu erkennen.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1979.010300402
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Morphologische Besonderheiten polymerer Mehrkomponentensysteme auf der Basis von Dithiolen und Diisocyanaten (1979)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 30 (1979), S. 496-502 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polyurethanes obtained by reacting mercapto-terminated oligobutadienes, decanedithiol and diisocyanate were investigated by electron microscopy and x-ray scattering. The dependence of the morphological structure on the content of short-chain dithiol is discussed. Heterogeneities in micro- and macroregions were observed, which are caused by crystalline regions and phase separation in chemically different blocks.
    Notes: Polyurethane auf der Basis von mercapto-terminierten Oligobutadienen, Decandithiol und Diisocyanat werden mittels Elektronenmikroskopie und Röntgenstreuung untersucht. Ihre morphologischen Besonderheiten werden in Abhängigkeit vom Gehalt an Kurzkettendithiol diskutiert. Es treten Heterogenitäten im Mikro- und Makrobereich auf, die durch kristalline Bereiche und Phasentrennung in chemisch unterschiedliche Blöcke bedingt sind.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1979.010300807
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