ALBERT

Description: Photooxidants play an important role for the oxidation capacity of the troposphere. The presented work deals with seasonal changes of atmospheric photooxidants like hydrogen peroxide (H2O2), methylhydroperoxide (MHP) and formaldehyde (HCHO). The principal purpose was to follow and quantify the mixing-ratios of these photochemical species for the first time over a complete annual cycle in Antarctica. During two field campaigns at the German Antarctic station Neumayer (overwintering campaign from January 1997 until March 1998 and a shorter campaign from January to March 1999) continuous measurements of atmospheric mixing-ratios were performed. A continuous wet-chemical technique was used for peroxides and formaldehyde sampling and analysis. Species were quantified by fluorescence detection. In order to compare the results and measurements with well-known reaction mechanisms a photochemical box model was applied. The obtained time series show a pronounced seasonal variation with higher values during summer. For the first time atmospheric concentrations of H2O2, MHP and HCHO were documented during polar night in winter. The mixing-ratios were significantly higher than expected due to missing actinic radiation essential for photochemical production. Trajectory analyses and calculations with a three-dimensional model showed that during winter the mixing-ratios of photooxidants are mainly affected by long-range transport in the free troposphere. Investigations during the Antarctic ó́zone hole period ́́show no significant impact of the increased UV-B radiation on the photooxidants. The findings of this work contribute to a better understanding of the photochemistry of the investigated trace gases in the clean troposphere of Antarctica and provide a useful data record for further photochemical modeling.

Description: thesis

Description: Besides measurements of atmospheric trace gases and laboratory studies of chemical reactions, modelling has been recognised to be of increasing importance to improve our knowledge of the atmosphere and the capabilities of photochemical models. Main scope of this work was the development of a photochemical atmospheric model, which was especielly designed for the interpretation of Differential Optical Absorption measurments (DOAS). This model has been used to improve our knowledge of atmospheric chemistry. For example, for the first time it was possible to demonstrate that a significant amount of IO in a range of 0.65 to 0.8 pptv is present in the stratosphere in the polar region (Ny-Alesund,Spitzbergen). Moreover it has been shown that such amounts of stratospheric IO lead to an additional Ozone loss in the range of 10 % in cold arctic winters.

Description: thesis

Description: Ozone profile retrieval, ERS-2, GOME, FURM, ozone decline, Northern hemisphere. - Measurements of stratospheric ozone over the Northern hemisphere forthe winter/spring periods of 1997 to 2000 taken with the GOMEinstrument were used to derive the chemical ozone depletion inside thepolar vortex. GOME onboard the ERS-2 satellite measures radiationcoming from the Earth in the UV/vis spectral range.To discern the chemical depletion from dynamical influences, a modelwas developed to calculate vortex averaged diabatic descent ratesusing the radiative transfer model MIDRAD and the FURM ozoneprofiles. The permeability of the Arctic vortex was analysed by usingthe trajectory model TANGO in conjunction with a reverse domainfilling algorithm, developed within the framework of this thesis.The chemical ozone ...

Description: thesis

Description: Ozone chemistry, tracer measurements, radiometry, airborne,submillimeterwave, Arctic, stratosphere. - The Airborne Submillimeter Radiometer (ASUR) is a passive heterodyne instrument using a superconducting detector with an instrumental frequency range from 604.3 to 662.3 GHz.Operating onboard an aircraft to avoid absorption by tropospheric water vapor key species of the stratospheric ozone chemistry can be detected for a vertical altitude range from 15 to 55 km. In the winter 1999/2000 the ASUR instrument participated in the THESEO 2000/SOLVE project onboard the NASA research aircraft DC-8. Three deployments were carried ...

Description: thesis

Description: thesis

Description: Thermohaline circulation, variability, energy and moisture balance model, paleoceanography. - Freshening of high latitude surface water can change the large scale oceanic transport of heat and salt. Consequently, atmospheric and sea ice perturbations over the deep water production sites excite a large scale response establishing an oceanic t̀̀eleconnection'' with time scales of years to centuries. To study these feed-backs, an atmospheric energy and moisture balance model (EMBM), predicting the heat and fresh water fluxes at the surface, and a thermodynamic sea ice model were constructed and coupled to the GFDL ocean model MOM2. The heat and moisture transports by transient eddies in the EMBM are parameterized by diffusion. The coupled model reproduces many aspects of today's oceanic circulation. The most interesting features of the coupled model are the sensitivity of the thermohaline circulation to changes in the configuration, the multidecadal variability in the ocean-sea ice system, and the behaviour of the thermohaline circulation during transitions between glacial and interglacial periods. A very strong thermohaline circulation develops in the coupled system that is not evident in the stand-alone ocean model. An interesting aspect of this behaviour is the existence of a maximum strength in the overturning. Beyond this maximum, evaporation in the subtropics cannot balance the northward salt-transport. As a result, the watermasses over the deep water production sites become fresher, leading to a collapse of the thermohaline circulation. The associated changes in the sea ice cover prevent the system to recover. ...

Description: thesis

Description: Dieser Band enthält 64 Artikel zu Themengebieten der Geophysik, veröffentlicht durch die Deutsche Geophysikalische Gesellschaft in den Jahren 1976 und 1977.

Description: Inhaltsverzeichnis: Journal of Geophysics 42 〈html〉 〈body〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0009.pdf"〉Short-Time Variations of Solar Particle Fluxes during the August 1972 Events〈/a〉〈br〉 (Kremser, G., Riedler, W., Kirsch, E.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0011.pdf"〉Auroral Lyman-Alpha Emission〈/a〉〈br〉 (Dose, V., Schmocker, U., Sele, G.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0012.pdf"〉The Gravity Field of Northeastern Iceland〈/a〉〈br〉 (Schleusener, A., Torge, W., Drewes, H.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0016.pdf"〉Parabolic Field Dependence of Kinks Occurring in the Logarithmic Time Plots of Viscous Magnetization〈/a〉〈br〉 (Markert, H., Heller, F., Steigenberger, N.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0018.pdf"〉Postulated Rotation of Corsica not Confirmed by New Palaeomagnetic Data〈/a〉〈br〉 (Storetvedt, K. M., Petersen, N.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0020.pdf"〉Magnetic Anomalies of the African Red Sea Shelf and Their Implications for the Anomalies of Atlantic Continental Margin〈/a〉〈br〉 (Roeser, H. A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0021.pdf"〉Self-Reversal above Room Temperature due to N-Type Magnetization in Basalt〈/a〉〈br〉 (Schult, A.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0022.pdf"〉Further Utilization of the Fluxgate Magnetometer in the Palaeomagnetic Laboratory〈/a〉〈br〉 (Hummervoll, R.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0023.pdf"〉Note on the Reliability of Subjective Processing of Geomagnetic Pulsation-Records in the Range Pc 2–Pc 5〈/a〉〈br〉 (Korschunow, A.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0024.pdf"〉Die Gesteinsradioaktivität und ihr Einfluß auf das Temperaturfeld in der kontinentalen Kruste〈/a〉〈br〉 (Rybach, L.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0025.pdf"〉A Lithospheric Seismic Profile in Britain〈/a〉〈br〉 (Kaminski, W., Bamford, D., Faber, S., Jacob, B., Nunn, K., Prodehl, C.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0026.pdf"〉Rayleigh Channel Waves for the In-Seam Seismic Detection of Discontinuities〈/a〉〈br〉 (Dresen, L., Freystätter, S.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0028.pdf"〉Ultrasonic Modelling of a Moving Source〈/a〉〈br〉 (Behle, A., Rohde, J.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0029.pdf"〉Propagation of Love-Type Waves in Heterogeneous Elastic Layers〈/a〉〈br〉 (Biswas, A.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0030.pdf"〉Representation and Interpretation of Resistivity Mapping Data in Groundwater Prospecting in Zambia〈/a〉〈br〉 (Töpfer, K. D.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0032.pdf"〉The Iranian Long Period Array (ILPA)〈/a〉〈br〉 (Akasheh, B., Eshghi, I., Soltanian, R.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0033.pdf"〉Appearance of the Atmospheric Scatter Field during a Solar Eclipse〈/a〉〈br〉 (Gerharz, R.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0034.pdf"〉Technique for Simultaneous Observation of Gravity and Vertical Gradient Data〈/a〉〈br〉 (Thyssen-Bornemisza, S.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0035.pdf"〉Modern Standards for Gravity Surveys〈/a〉〈br〉 (Morelli, C.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0036.pdf"〉Book Reviews〈/a〉〈br〉 (Schick, R., Rummel, F.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0037.pdf"〉Tunneling of Low-Frequency Waves through the Subcrustal Lithosphere〈/a〉〈br〉 (Fuchs, K., Schulz, K.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0041.pdf"〉Computation of Reflection Coefficients for Layered Media〈/a〉〈br〉 (Kind, R.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0042.pdf"〉The Seismic Broadband Recording and Data Processing System FBV/DPS and Its Seismological Applications〈/a〉〈br〉 (Plešinger, A., Horálek, J.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0045.pdf"〉Intermediate Aseismicity of the Andean Subduction Zone and Recent Andesitic Volcanism〈/a〉〈br〉 (Hanuš, V., Vaněk, J.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0046.pdf"〉Provisional Seismicity Map of the Republic of Zambia and Its Preliminary Interpretation〈/a〉〈br〉 (Töpfer, K. D.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0047.pdf"〉Goethermal Models of the Crust and Uppermost Mantle of the Fennoscandian Shield on South Norway and the Danish Embayment〈/a〉〈br〉 (Balling, N. P.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0048.pdf"〉Spatial Characteristics of Giant Pulsations〈/a〉〈br〉 (Hillebrand, O.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0050.pdf"〉Latitude-Dependent Waves and Impulse-Produced Waves〈/a〉〈br〉 (Lanzerotti, L. J., Hasegawa, A.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0051.pdf"〉Study of the Spatial Variation of the Magnetic Field Intensity on North-South Profiles in Iran in Comparison with the IGRF Model of 1970〈/a〉〈br〉 (Guya, N. H.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0053.pdf"〉Seismische Oberflächenwellen〈/a〉〈br〉 (Seidl, D., Müller, S.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0055.pdf"〉Crustal Structure of the Central Aegean Sea and the Island of Evia and Crete, Greece, Obtained by Refractional Seismic Experiments〈/a〉〈br〉 (Makris, J., Vees, R.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0057.pdf"〉Fault-Plane Solution of the Earthquake in Northern Italy, 6 May 1976, and Implications for the Tectonics of the Eastern Alps〈/a〉〈br〉 (Müller, G.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0058.pdf"〉Pseudo-Single-Domain Effects and Single-Domain Multidomain Transition in Natural Pyrrhotite Deduced from Domain Structure Observations〈/a〉〈br〉 (Soffel, H.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0059.pdf"〉The Diurnal Variation of the Electron Density of the Mid-Latitude Ionospheric D-Region Deduced from VLF-Measurements〈/a〉〈br〉 (Schäfer, J.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0061.pdf"〉A Detailed Investigation of the Canadian Cordillera Geomagnetic Transition Anomaly〈/a〉〈br〉 (Dragert, H., Clarke, G. K. C.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0065.pdf"〉Magnetotelluric Investigation of a Nearly Circular Saltdome in North Germany〈/a〉〈br〉 (Breymann, U.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0066.pdf"〉Comments on: Postulated Rotation of Corsica not Confirmed by New Palaeomagnetic Data〈/a〉〈br〉 (Westphal, M.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0067.pdf"〉Reply〈/a〉〈br〉 (Storetvedt, K. M., Petersen, N.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0068.pdf"〉Structure of Lunar Impact Craters from Gravity Models〈/a〉〈br〉 (Janle, P.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0069.pdf"〉A Refined Crustal Model and the Isostatic State of the Scandinavian Blue Road Area〈/a〉〈br〉 (Goldflam, St., Hirschleber, H. B., Janler, P.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0070.pdf"〉Earth-Flattening Approximation for Body Waves Derived from Geometric Ray Theory – Improvements, Corrections and Range of Applicability〈/a〉〈br〉 (Müller, G.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0071.pdf"〉On the Variation of Kp at Sector Boundaries〈/a〉〈br〉 (Schreiber, H.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0072.pdf"〉Probleme bei der Untersuchung von räumlich und zeitlich veränderlichen Medien, dargestellt am Beispiel der Ionosphäre〈/a〉〈br〉 (Dieminger, W., Hartmann, G. K.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0073.pdf"〉Heat Flow Map of the Bohemian Massif〈/a〉〈br〉 (Čermák, V.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0074.pdf"〉Palaeomagnetic and Rock Magnetic Investigations of Tertiary Volcanics in Northern Bavaria〈/a〉〈br〉 (Pohl, J., Soffel, H.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0078.pdf"〉Palaeomagnetism of Upper Jurassic Limestones from Southern Germany〈/a〉〈br〉 (Heller, F.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0079.pdf"〉The Maximum Entropy Approach to Inverse Problems〈/a〉〈br〉 (Rietsch, E.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0080.pdf"〉Electromagnetic Scale Model Experiments for the Coastline Effect of Geomagnetic Variations〈/a〉〈br〉 (Spitta, P.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0081.pdf"〉Model Studies on Redox Logging for Minerals〈/a〉〈br〉 (Roy, K. K., Baksi, S. S.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0084.pdf"〉Modelling of the Ionosphere and Comparison of the Calculated and Observed Cosmic Radio Noise Absorption over Delhi〈/a〉〈br〉 (Sharma, M. C., Sarma, S. B. S. S.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0086.pdf"〉Winter Anomaly in VHF Absorption Studies over Delhi〈/a〉〈br〉 (Sarma, S. B. S. S., Sharma, M. C.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0089.pdf"〉In Memoriam Hermann Reich〈/a〉〈br〉 (Closs, H.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0094.pdf"〉Plasma Disturbances Caused by Helios in the Solar Wind〈/a〉 〈i〉Seiten 581-582 fehlen〈/i〉〈br〉 (Isensee, U.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0095.pdf"〉Radial Variation of the Interplanetary Magnetic Field Between 0.3 AU and 1.0 AU〈/a〉〈br〉 (Musmann, G., Neubauer, F. M.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0096.pdf"〉Initial Results from the Helios-1 Search-Coil Magnetometer Experiment〈/a〉〈br〉 (Neubauer, F.M., Beinroth, H. J., Barnstorf, H., Dehmel, G.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0100.pdf"〉Cosmic Ray Measurements on Board Helios 1 from December 1974 to September 1975: Quiet Time Spectra, Radial Gradients, and Solar Events〈/a〉〈br〉 (Kunow, H., Witte, M., Wibberenz, G., Hempre, H., Mueller-Mellin, R., Green, G., Iwers, B., Fuckner, J.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0102.pdf"〉A Survey on Measurements of Medium Energy Protons and Electrons Obtained with the Particle Spectrometer E8 on Board of Helios〈/a〉〈br〉 (Keppler, E., Richter, A. K., Richter, K., Umlauft, G., Wilken, B., Williams, D. J.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0105.pdf"〉Interaction of Low-Energy (〉80 keV) Protons with the January 6 and 8, 1975, Shock Waves: Helios-1 Observations〈/a〉〈br〉 (Richter, A. K., Keppler, E.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0107.pdf"〉Helios-1 Faraday Rotation Experiment: Results and Interpretations of the Solar Occultations in 1975〈/a〉〈br〉 (Volland, H., Bird, M. K.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0109.pdf"〉Time Delay Occultation Data of the Helios Spacecrafts and Preliminary Analysis for Probing the Solar Corona〈/a〉〈br〉 (Edenhofer, P., Esposito, P. B., Hansen, R. T., Hansen, S. F., Lüneburg, E., Martin, W. L., Zygielbaum, A. I.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0111.pdf"〉Observatons of Zodiacal Light from Helios 1 and 2〈/a〉〈br〉 (Leinert, C., Pitz, E., Hanner, M., Link, H.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0112.pdf"〉Interpretation of the Optical Properties of Interplanetary Dust〈/a〉〈br〉 (Giese, R. H.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0114.pdf"〉Micrometeoroid Data from the First Two Orbits of Helios 1〈/a〉〈br〉 (Grün, E., Fechtig, H., Kissel, J., Gammelin, P.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0116.pdf"〉Dynamical Effects on Circumsolar Dust Grains〈/a〉〈br〉 (Schwehm, G., Rohde, M.)〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0042/LOG_0118.pdf"〉Micrometeoroid Orbits Observable by the Helios Micrometeoroid Detector (E 10)〈/a〉〈br〉 (Schmidt, K. D.)〈/li〉 〈/body〉 〈/html〉

Description: research

Description: DFG, SUB Göttingen

Description: Sea-ice, Finite Element Sea-Ice Model, Kalman Filter, Data Assimilation. - The Arctic region is sensitive to climate change. Since the Arctic sea-ice cover influences the surface heat budget of the Earth the observed sea-ice decline is seen as an indication of global warming. Furthermore, the dynamics of sea ice plays an important role for the sea-ice mass distribution in the Arctic, for the production of dense, cold, and salty water in the Arctic Ocean, which contributes to the thermohaline circulation, and also for the freshwater budget of the Nordic Seas. Thus, a realistic description of sea-ice motion is important to draw conclusions for the mass transport and sea-ice mass distribution. The Finite-Element Sea-Ice Model simulates the large-scale physical sea-ice processes like the sea-ice growth and circulation realistically. The model domain covers the entire Arctic Ocean and its marginal seas. Together with the Singular Evolutive Interpolated Kalman (SEIK) Filter and remotely sensed sea-ice drift observations this sea-ice model is applied for data assimilation to investigate details of the sea-ice dynamics. So far, drift assimilation has been carried out to analyze and modify only the drift field with subsequent computation of the advection or redistribution of ice mass which corresponds more to the physical model behavior than a statistical analysis that the SEIK Filter provides. The sea-ice drift data assimilation with the SEIK Filter achieves drift modification and furthermore changes in the two other sea-ice variables concentration and thickness. The modifications of these "unobserved variables" (within the meaning of data assimilation) are validated and it is found that they are in good agreement for at least 2 months for the sea-ice thickness and even 4 months for the sea-ice concentration which is the longest period examined. The drift improvement is achieved due to the sea-ice concentration and ...

Description: thesis

Description: Tectonics, marine geophysics, plate-tectonic reconstruction, new zealand, antarctica, seismic refraction/wide-angle reflection, Gondwana break-up. - The last supercontinent fell into pieces with the break-up of Gondwana. In this context, the separation of the microcontinent of New Zealand from Antarctica is a jigsaw puzzle of many pieces. Its parts lay at the convergent margin of East Gondwana, which changed into a divergent margin within a geologically short time. That is why the microcontinent of New Zealand experienced different tectonic regimes and phases of the Wilson cycle. Although it is a good object of investigation due to its changing history, remarkably little is known about the submerged parts of the microcontinent. Knowledge of the magmatic-tectonic development of the submarine plateaux such as Campbell Plateau and Chatham Rise will improve the understanding of the processes that led to the late Gondwana break-up, and, in turn, lead to better reconstructions of East Gondwana, as Zealandia is a key piece in plate-kinematic reconstructions of this part of Gondwana. The central part of this thesis deals with the separation process of Zealandia from Antarctica leading to an improved reconstruction of New Zealand with emphasis on the submarine plateaux. Bounty Trough separating Chatham Rise from Campbell Plateau, and the Great South Basin separating Campbell Plateau from the South Island are investigated with seismic refraction and reflection methods. They are interpreted jointly with magnetic and gravity data. The results of crustal thickness modelling based on satellite gravity data are combined with existing information about crustal thickness of Zealandia. With these data ...

Description: thesis

Description: Reflection seismics, sediment drifts, bottom currents. - The region south of South Africa has been a crucial gateway for large scale Thermohaline Circulations since late Eocene times. Here, three of the most important currents for maintaining the global heat exchange, namely the warm and surface related Agulhas Current (AC), and the cold and denser North Atlantic Deep Water (NADW) as well as the Atlantic Bottom Water (AABW), flow around South Africa. Due to the special tectonic and geologic situation, a huge amount of the deep and bottom water masses that flow around South Africa have to pass the narrow Agulhas Passage, located between the South African continental shelf and the submarine Agulhas Plateau. As a result, the sedimentary infill of the Transkei Basin, which is located east of the Agulhas Plateau, has been predominantly influenced by NADW and AABW activity since ~36 Ma. Via the analysis of this sedimentary infill, a palaeo current reconstruction of (proto-) NADW and (proto-) AABW revealed changing flow paths and flow strengths since then. These variations in current attributes were triggered by large scale effects, such as the opening of the Tasman Gateway and the Drake Passage in the Late Eocene, or the closure of the Isthmus of Panama in the Pliocene. A more detailed analysis of the Transkei Basin's depocentre locations and interface outlines resulted in a palaeo flow path reconstruction for this region. Moreover, palaeo climate conditions from the Late Cretaceous were partially reconstructed ...

Description: thesis