archive-de.com » DE » G » GEO-LEO.DE

Total: 1104

Choose link from "Titles, links and description words view":

Or switch to "Titles and links view".
  • Development and application of 2D and 3D transient electromagnetic inverse solutions based on adjoint Green functions
    of transient electromagnetic TEM methods a multidimensional inverse solution is introduced which allows for a explicit sensitivity calculation with reduced computational effort The main conservation of computational load is obtained by solving Maxwell s equations directly in time domain This is achieved by means of a high efficient Krylov subspace technique that is particularly developed for the fast computation of EM fields in the diffusive regime Traditional modeling procedures for Maxwell s equations yields solutions independently for every frequency or in the time domain at a given time through explicit time stepping Because of this frequency domain methods are rendered extremely time consuming for multi frequency simulations Likewise the stability conditions required by explicit time stepping techniques often result in highly inefficient calculations for large diffusion times and conductivity contrasts The computation of sensitivities is carried out using the adjoint Green functions approach For time domain applications it is realized by convolution of the background electrical field information originating from the primary signal with the impulse response of the receiver acting as secondary source In principle the adjoint formulation may be extended allowing for a fast gradient calculation without calculating and storing the whole sensitivity matrix but just the gradient

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-3178-1 (2016-02-15)
    Open archived version from archive


  • Late Quaternary environmental history of Taylor Valley, southern Victoria Land, Antarctica, reconstructed by a multidisciplinary study of lake sediments
    Kategorien Klimaschwankungen und Klimaänderungen im Quartär Quartär Paläolimnologie Geologie Antarktis Geologie Geochronologie einzelner Regionen im allgemeinen Geologische Bohrungen in einzelnen Regionen Zur Langanzeige Zusammenfassung In the unglaciated areas of Antarctica lake sediments act as archives of the regional environmental and climatic history In most cases the records are restricted to the Holocene Amongst the few exceptions are lakes in the McMurdo Dry Valleys southern Victoria Land which are known to have remained mostly ice free during the Last Glacial Maximum Within the scope of an U S American German expedition in austral summer 2002 2003 several sediment cores were recovered from the three major lakes in the Taylor Valley lakes Fryxell Hoare and Bonney In order to reconstruct the late Quaternary regional environmental and climate history sedimentological biogeochemical mineralogical and chronological investigations were conducted on the sediment sequences recovered from Lake Hoare core Lz1020 and East Lake Bonney core Lz1023 within the scope of this thesis Sediment cores from Lake Hoare with a maximum length of 2 3 m mainly consist of coarse grained material and penetrate back into the late Weichselian when Taylor Valley was occupied by the large proglacial Lake Washburn This lake was dammed by the advanced

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-3177-3 (2016-02-15)
    Open archived version from archive

  • Untersuchungen zur Gaschemie und Anwendbarkeit isotopischer Geothermometrie an hydrothermalen Systemen des mittelatlantischen Rückens
    net 11858 00 1735 0000 0001 3176 5 Dateiname Weber2009 pdf PDF 6 1 MB Google View Download Kategorien Geothermische Verfahren Geophysik Druck und Temperaturbestimmungen Mineralogie Atlantischer Ozean Geophysik Atlantischer Ozean Geologie Zur Langanzeige Zusammenfassung In der vorliegenden Arbeit wurde untersucht welche Parameter die Anwendbarkeit der Geothermometer für Wasserstoff im System Wasserstoff Methan Wasser und Kohlenstoff im System Methan Kohlendioxid bestimmen Dazu wurden die Hydrothermalsysteme Turtle Pits Red Lion Comfortless Cove Wideawake Lilliput Nibelungen und Logatchev untersucht Analysen der Wassersäule zeigten hydrothermale Prägung wie erhöhte Konzentration von Wasserstoff und Methan sowie eine erhöhte Trübe des Seewassers bei schwarzen Rauchern Diese Untersuchungen führten auch zur Entdeckung des südlichsten bekannten Hydrothermalfeldes im Atlantik dem Lilliputfeld Es wurden Messungen der Konzentration und der Isotopensignatur von Wasserstoff und Methan durchgeführt Die Hydrothermalsysteme wurden zusätzlich mit Hilfe von weiteren fluidchemischen Daten und geologischen Eigenschaften der Quellen charakterisiert Aus den Isotopendaten konnte mit Hilfe der Gleichung für die isotopische Gleichgewichtsfraktionierung eine apparente Isotopentemperatur berechnet werden Es wurde untersucht inwieweit diese apparente Temperatur den realen Temperaturen in den Hydrothermalsystemen entspricht Beim Wasserstoffthermometer konnte eine gute Vereinbarkeit mit der Austrittstemperatur fokussierter Quellen festgestellt werden Für diffuse Quellen gilt dies jedoch nicht da bei diesen häufg eine Vermischung mit

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-3176-5 (2016-02-15)
    Open archived version from archive

  • The sediment record of Lake Ohrid (Albania/Macedonia)
    Dateiname Vogel2009 pdf PDF 19 4 MB Google View Download Zur Langanzeige Zusammenfassung This thesis had two primary objectives One objective was to explore and develop applications of Fourier transform infrared spectroscopy FTIRS for the quantification of biogeochemical properties in lake sediment the other objective was to assess the Lake Ohrid Albania Macedonia sediment record with an emphasis on tephrostratigraphy and inferences of climatic and environmental changes using a 15 m long sediment succession core Co1202 from the north eastern part of the lake Studies presented in this thesis were conducted within the scope of an envisaged deep drilling campaign at Lake Ohrid and therefore represent important preliminary studies FTIR spectra of lacustrine sediment samples were calibrated to infer concentrations of total organic carbon TOC total inorganic carbon TIC total nitrogen TN and biogenic silica BSi To test the applicability of the FTIRS technique site specific FTIRS calibrations and FTIRS calibrations based on a surface sediment dataset from 94 northern Swedish lakes were constructed Both approaches demonstrated significant correlations between FTIRS inferred and conventionally assessed biogeochemical property concentrations ranging between R2 0 79 0 99 for TOC R2 0 85 0 99 for TIC R2 0 62 0 84 for

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-3174-9 (2016-02-15)
    Open archived version from archive

  • Neon, Helium and Argon isotope systematics of the Hawaiian hotspot
    Mailer2009 pdf PDF 1 5 MB Google View Download Kategorien Isotopengeologie Regionaler Vulkanismus Geologie Pazifischer Ozean Geologie Pazifischer Ozean Geophysik Zur Langanzeige Zusammenfassung This study presents noble gas compositions He Ne Ar Kr and Xe of lavas from several Hawaiian volcanoes Lavas from the Hawaii Scientific Drilling Project HSDP core surface samples from Mauna Kea Mauna Loa Kilauea Hualalai Kohala and Haleakala as well as lavas from a deep well

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-3172-D (2016-02-15)
    Open archived version from archive

  • Diurnal to annual variability of the atmospheric boundary layer over West Africa
    by the pronounced contrast between tropical moist air masses over the Gulf of Guinea in the south and the dry desert climate over the Sahara in the north The sharp border between the two air masses exhibits a pronounced meridional annual cycle and follows the path of the sun northward This circulation system is called West African monsoon 34 In the past the knowledge about the factors that control the monsoon and its strength was limited due to the small number of high quality observations Therefore little is known about the reasons for the significant decline of annual rainfall over the Sahel area during the past 40 years which represents the most pronounced climatic signal worldwide During the past few years intensive atmospheric observations were performed in the framework of the international project 34 African Monsoon Multidisciplinary Analyses 34 AMMA in order to obtain high quality data and to improve the process understanding This work gathered and analyzed ground based remote sensing observations which were performed in Benin and Niger during the AMMA field campaigns These data give an insight into diurnal and annual cycles of atmospheric parameters such as water vapor temperature profiles cloud cover cloud liquid water content

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-3171-F (2016-02-15)
    Open archived version from archive

  • Geophysik Alle Dokumente nach Autor
    geben Sie die ersten Buchstaben ein Sortierung aufsteigend absteigend Ergebnisse 5 10 20 40 60 80 100 Anzeige der Dokumente 45 64 von 369 Vorherige Seite Nächste Seite Autorenname Dannowski Grit Daßinnies Matthias Ch Delacou Bastien Demirel Hande Dengler Marcus Devey Colin Dillon Melanie Dill Robert Ding Feng Dobslaw Henryk Donnelly Alison Donner Ralf Donner Reik Dorner Dorothée Dostal Jan Duhnke Karin Eckert Andreas Ehrhardt Lutz Axel Ehrlich Heike Eichmann

    Original URL path: http://e-docs.geo-leo.de/handle/11858/512/browse?rpp=20&order=ASC&sort_by=-1&etal=-1&type=author&starts_with=D (2016-02-15)
    Open archived version from archive

  • Geophysik Alle Dokumente nach Autor
    Sie die ersten Buchstaben ein Sortierung aufsteigend absteigend Ergebnisse 5 10 20 40 60 80 100 Anzeige der Dokumente 141 160 von 372 Vorherige Seite Nächste Seite Autorenname Itter Arndt Jaksch Katrin Jiang Xiaodian Jochmann Horst Kahl Wolf Achim Kaiser Claudia Kaiser Johannes W Karow Tobias Kaschenz Julia Kaschwich Tina Kellner Antje Kern Stefan Kesten Dagmar Khiry Manal Awad Kickelbick Dirk Kito Tadashi Klasen Nicole Klauw Sebastiaan Nicolaas Gerardus Cornelis

    Original URL path: http://e-docs.geo-leo.de/handle/11858/512/browse?rpp=20&order=ASC&sort_by=-1&etal=-1&type=author&starts_with=I (2016-02-15)
    Open archived version from archive



  •