ALBERT

Beschreibung: Dieser Band enthält Artikel zu 41 Themengebieten der Geophysik, veröffentlicht durch die Deutsche Geophysikalische Gesellschaft in dem Jahr 1981.

Beschreibung: Inhaltsverzeichnis: Journal of Geophysics 49 〈html〉 〈body〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0011.pdf"〉Palaeomagnetism of a Jurassic Ophiolite Series in East Elba (Italy) 〈/a〉〈br〉 (Soffel, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0013.pdf"〉Paleomagnetic Evidence from Mesozoic Carbonate Rocks for the Rotation of Sardinia〈/a〉〈br〉 (Horner, F., Lowrie, W.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0015.pdf"〉A Geotectonic Paradox: Has the Earth Expanded? 〈/a〉〈br〉 (Schmidt, P. W., Embleton, B. J. J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0016.pdf"〉Application of Magnetotelluric and DC Electrical Resistivity Methods in the Neapolitan Geothermal Area〈/a〉〈br〉 (Hunsche, U., Rapolla, A., Musmann, G., Alfano, L.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0018.pdf"〉Velocity Variations in Systems of Anisotropic Symmetry〈/a〉〈br〉 (Crampin, S., Kirkwood, S. C.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0019.pdf"〉Shear-Wave Singularities of Wave Propagation in Anisotropic Media〈/a〉〈br〉 (Crampin, S., Yedlin, M.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0020.pdf"〉Temperature Derivatives of Compressional and Shear Wave Velocities in Crustal and Mantle Rocks at 6 kbar Confining Pressure〈/a〉〈br〉 (Kern, H., Richter, A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0021.pdf"〉A Crustal Gravity Model of the Mare Serenitatis - Mare Crisium Area of the Moon〈/a〉〈br〉 (Janle, P.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0022.pdf"〉On the Origin of the Annual Wave in Hemispheric Geomagnetic Activity〈/a〉〈br〉 (Meyer, J., Damaske, D.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0023.pdf"〉On the Relation Between Magnetic Field-Aligned Electrostatic Electron Acceleration and the Resulting Auroral Energy Flux〈/a〉〈br〉 (Wilhelm, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0024.pdf"〉Application of Different Methods for the Determination of Ionospheric Conductivities from Sounding Rocket Observations〈/a〉〈br〉 (Brüning, K., Baumjohann, W., Wilhelm, K., Stüdemann, W., Urban, A., Ott, W., Spenner, K., Schmidtke, G. L., Fischer, H. M.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0025.pdf"〉Numerical Experiments on Convection in a Chemically Layered Mantle〈/a〉〈br〉 (Christensen, U.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0026.pdf"〉〈i〉Book Reviews〈/i〉〈/a〉〈br〉 (Raikes, S. A., Engelhard, L., Pape, H., Theile, B.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0028.pdf"〉Steady State Creep of Fine Grain Granite at Partial Melting〈/a〉〈br〉 (Auer, F., Berckhemer, H., Oehlschlegel, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0029.pdf"〉Laboratory Synthesis of Aluminium-Substituted Titanomaghemites and Their Characteristic Properties〈/a〉〈br〉 (Özdemir, Ö, O’Reilly, W.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0030.pdf"〉Densities and Magnetic Susceptibilities of Precambrian Rocks of Different Metamorphic Grade〈/a〉〈br〉 (Southern Indian Shield) (Subrahmanyam, C., Verma, R. K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0031.pdf"〉Lithospheric Structure and Teleseismic 〈i〉P〈/i〉-Wave Reflection Delays Under Fennoscandia and Siberia〈/a〉〈br〉 (Stewart, Ian C. F.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0033.pdf"〉Propagation of Surface Waves in Marine Sediments〈/a〉〈br〉 (Essen, H.-H., Janle, H., Schirmer, F., Siebert, J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0035.pdf"〉Simultaneous Observation of an Intense 65 keV Field-Aligned Proton Beam and ULF-waves During a Break-up Event〈/a〉〈br〉 (Stüdemann, W., Goertz, C. K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0036.pdf"〉Observations of Field-Aligned Current Sheets Above Discrete Auroral Arcs〈/a〉〈br〉 (Wilhelm, K., Klöcker, N., Theile, B., Ott, W., Spenner, K., Grabowski, R., Wolf, H., Stüdemann, W., Dehmel, G., Fischer, H. M., Schmidtke, G. L., Baumjohann, W., Riedler, W., Urban, A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0038.pdf"〉Multi-Method Observations and Modelling of the Three-Dimensional Currents Associated with a Very Strong Ps6 Event〈/a〉〈br〉 (Gustafsson, G., Baumjohann, W., Iversen, I.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0040.pdf"〉Variability of Solar EUV Fluxes and Exospheric Temperatures〈/a〉〈br〉 (Schmidtke, G., Börsken, N., Sünder, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0041.pdf"〉Paleomagnetism of Quaternary and Miocene Lavas from North-East and Central Morocco〈/a〉〈br〉 (Najid, D., Westphal, M., Hernandez, J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0042.pdf"〉In Memoriam Wilhelm Hiller〈/a〉〈br〉 (Schneider, Götz)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0043.pdf"〉〈i〉Book Reviews〈/i〉〈/a〉〈br〉 (Wilhelm, H., Neubauer, F. M., Schopper, J. R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0044.pdf"〉Joint Two-Dimensional Observations of Ground Magnetic and Ionospheric Electric Fields Associated with Auroral Zone Currents〈/a〉〈br〉 (Inhester, B., Baumjohann, W., Greenwald, R. A., Nielsen, E.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0045.pdf"〉Current Flow in Auroral Forms Responsible for Ps 6 Magnetic Disturbances〈/a〉〈br〉 (Rostoker, G., Apps, K. S.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0046.pdf"〉Correlation of Geomagnetic Activity Indices ap with the Solar Wind Speed and the Southward Interplanetary Magnetic Field〈/a〉〈br〉 (Schreiber, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0047.pdf"〉High Time-Resolution Correlation Between the Magnetic Field Behaviour at 37 〈i〉R〈/i〉〈sub〉E〈/sub〉 Distance in the Magnetotail Plasma Sheet and Ground Phenomena During Substrom Expansive Phase〈/a〉〈br〉 (Sergeev, V. A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0048.pdf"〉Simultaneous Observations of Energetic Protons Close to the Bow Shock and Far Upstream〈/a〉〈br〉 (Scholer, M., Ipavich, F. M., Gloeckler, G., Hovestadt, D.)〈/a〉〈/li〉 〈li〉〈a href=" https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0049.pdf"〉Non-Adiabatic Expansion of Low-Temperature Solar Wind Radial Temperature Gradients〈/a〉〈br〉 (Geranios, A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0050.pdf"〉Correlation Between Seismic Microactivity, Temperature and Subsidence of Water Level at Reservoirs〈/a〉〈br〉 (Merkler, G., Bock, G., Fuchs, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0052.pdf"〉〈sup〉40〈/sup〉Ar/〈sup〉39〈/sup〉Ar Dating of Himalayan Rocks from the Mount Everest Region〈/a〉〈br〉 (Kaneoka, Ichiro, Kono, Masaru)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0053.pdf"〉A Comparison of the Thermal and Mechanical Structure of the Lithosphere Beneath the Bohemian Massif and the Pannonian Basin〈/a〉〈br〉 (Onuoha, K. M.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0054.pdf"〉Extremal Models for Electromagnetic Induction in Two-Dimensional Perfect Conductors〈/a〉〈br〉 (Weidelt, P.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0055.pdf"〉On a Type Classification of Lower Crustal Layers Under Precambrian Regions〈/a〉〈br〉 (Jones, A. G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0056.pdf"〉Spherical-Earth Gravity and Magnetic Anomaly Modeling by Gauss-Legendre Quadrature Integration〈/a〉〈br〉 (Frese, R. R. B., Hinze, W. J., Braile, L. W., Luca, A. J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0057.pdf"〉Detection Probabilities for Earthquakes in Sweden〈/a〉〈br〉 (Shapira, A., Kulhánek, O., Wahlström, R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0058.pdf"〉The Geocyclotron Revisited: Potentialities of Modulated Wave Injection〈/a〉〈br〉 (Brinca, A. L.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0059.pdf"〉Eine kleine Historie zur Namengebung der Fachdisziplin Geophysik〈/a〉〈br〉 (Buntebarth, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0049/LOG_0060.pdf"〉〈i〉Correction〈/i〉: High Precision Measurement of the Frequency of Mode 〈sub〉0〈/sub〉S〈sub〉0〈/sub〉〈/a〉〈br〉 (Zürn, W., Knopoff, L., Rydelek, P. A.)〈/a〉〈/li〉 〈/body〉 〈/html〉

Beschreibung: research

Beschreibung: DFG, SUB Göttingen

Beschreibung: Dieser Band enthält 78 Artikel zu Themengebieten der Geophysik, veröffentlicht durch die Deutsche Geophysikalische Gesellschaft in dem Jahr 1977.

Beschreibung: Inhaltsverzeichnis: Journal of Geophysics 43 〈html〉 〈body〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0012.pdf"〉Editors' Preface〈/a〉〈br〉 (Fuchs, K., Müller, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0013.pdf"〉Full Wave Theory Applied to a Discontinuous Velocity Increase: The Inner Core Boundary〈/a〉〈br〉 (Cormier, V. F., Richards, P. G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0016.pdf"〉Propagation of Elastic Waves in Vertically Inhomogeneous Media〈/a〉〈br〉 (Ungar, A., Ilan, A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0017.pdf"〉Finite-Difference Modelling for P-Pulse Propagation in Elastic Media with Arbitrary Polygonal Surface〈/a〉〈br〉 (Ilan, A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0020.pdf"〉Extension of Matrix Methods to Structures with Slightly Irregular Stratification〈/a〉〈br〉 (Cisternas, A., Jobert, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0021.pdf"〉Modal Approach to Wave Propagation in Layered Media with Lateral Inhomogeneities〈/a〉〈br〉 (Saastamoinen, P. R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0022.pdf"〉On the Propagation of Seismic Pulses in a Porous Elastic Solid〈/a〉〈br〉 (Mainardi, F., Servizi, G., Turchetti, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0023.pdf"〉Three-Dimensional Seismic Ray Tracing〈/a〉〈br〉 (Julian, B. R., Gubbins, D.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0025.pdf"〉On Geophysical Inverse Problems and Constraints〈/a〉〈br〉 (Sabatier, P. C.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0027.pdf"〉On Impulse Response Data and the Uniqueness of the Inverse Problem〈/a〉〈br〉 (Barcilon, V.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0028.pdf"〉Least-Squares Collocation and the Gravitational Inverse Problem〈/a〉〈br〉 (Moritz, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0029.pdf"〉The Statistical Description and Interpretation of Geophysical Potential Fields Using Covariance Functions〈/a〉〈br〉 (Kautzleben, H., Harnisch, M., Schwahn, W.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0030.pdf"〉A Finite Element Program Package for Electromagnetic Modeling〈/a〉〈br〉 (Kaikkonen, P.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0032.pdf"〉Linear Inverse Problem in Gravity Profile Interpretation〈/a〉〈br〉 (Vigneresse, J. L.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0034.pdf"〉Data Seizing and Information Processing〈/a〉〈br〉 (Picard, C. F., Sallantin, J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0035.pdf"〉Formal Morphostructural Zoning of Mountain Territories〈/a〉〈br〉 (Alekseevskaya, M., Gabrielov, A., Gel’fand, I., Gvishiani, A., Rantsman, E.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0036.pdf"〉Three Dimensional Seismic Velocity Anomalies in the Lithosphere〈/a〉〈br〉 (Aki, Keiiti)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0038.pdf"〉The Inversion of Long Range Seismic Profiles〈/a〉〈br〉 (Kennett, B. L. N.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0040.pdf"〉An Oceanic Long Range Explosion Experiment〈/a〉〈br〉 (Orcutt, J. A., Dorman, L. M.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0041.pdf"〉The Upper Mantle Under Western Europe Inferred from the Dispersion of Rayleigh Modes〈/a〉〈br〉 (Nolet, Guust)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0044.pdf"〉Global and Regional Phase Velocities of Long-Period Fundamental Mode Rayleigh Waves〈/a〉〈br〉 (Mitronovas, W.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0045.pdf"〉The Inversion of Surface Wave Dispersion Data with Random Errors〈/a〉〈br〉 (Knopoff, L., Chang, F.-S.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0048.pdf"〉Finite Difference Calculation of Stress Relaxation Earthquake Models〈/a〉〈br〉 (Stöckl, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0050.pdf"〉On Equivalent Models of Seismic Sources〈/a〉〈br〉 (Jobert, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0051.pdf"〉A Method for Synthesis of the Seismic Coda of Local Earthquakes〈/a〉〈br〉 (Herrmann, R. B.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0055.pdf"〉Application of Two-Timing Methods in Statistical Geophysics〈/a〉〈br〉 (Hasselmann, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0056.pdf"〉Scattered Waves in the Coda of P〈/a〉〈br〉 (Hudson, J. A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0057.pdf"〉Elastic Wave Propagation in a Highly Scattering Medium – A Diffusion Approach〈/a〉〈br〉 (Dainty, A. M., Toksöz, M. N.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0058.pdf"〉Seismic Energy Transmission in an Intensively Scattering Environment〈/a〉〈br〉 (Nakamura, Yosio)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0060.pdf"〉Scattering of Rayleigh Waves by a Ridge〈/a〉〈br〉 (Sabina, F. J., Willis, J. R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0061.pdf"〉Mean-Field Electrodynamics and Dynamo Theory of the Earth's Magnetic Field〈/a〉〈br〉 (Krause, F.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0064.pdf"〉An Example of Nonlinear Dynamo Action〈/a〉〈br〉 (Busse, F. H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0065.pdf"〉Energetics of the Earth's Core〈/a〉〈br〉 (Gubbins, D.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0066.pdf"〉Equation of State of Liquid Iron at the Earth's Core Conditions〈/a〉〈br〉 (Boschi, E., Mulargia, F.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0067.pdf"〉Lithospheric Slab Penetration into the Lower Mantle beneath the Sea of Okhotsk〈/a〉〈br〉 (Jordan, T. H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0069.pdf"〉〈i〉Abstracts and Short Communications〈/i〉〈/a〉〈br〉〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0068.pdf"〉Phenomenological Representation of Seismic Sources〈/a〉〈br〉 (Backus, G., Mulcahy, M.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0070.pdf"〉The Influence of the Core and the Oceans on the Chandler Wobble〈/a〉〈br〉 (Dahlen, F. A., Smith, M. L.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0071.pdf"〉The Earth's Core-Mantle Interface Revisited〈/a〉〈br〉 (Hide, R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0072.pdf"〉Seismic Observations of Structure and Physical Properties of the Subcrustal Lithosphere as Evidence for Dynamical Processes in the Upper Mantle〈/a〉〈br〉 (Fuchs, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0073.pdf"〉Seismic Anisotropy – a Summary〈/a〉〈br〉 (Crampin, Stuart)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0074.pdf"〉Precise Continuous Monitoring of Seismic Velocity Variations〈/a〉〈br〉 (Bungum, H., Risbo, T., Hjortenberg, E.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0075.pdf"〉On the Computation of Theoretical Seismograms for Multimode Surface Waves〈/a〉〈br〉 (Calcagnile, G., Panza, G. F., Schwab, F., Kausel, E.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0076.pdf"〉On the Excitation of the Earth's Seismic Normal Modes〈/a〉〈br〉 (Vlaar, N. J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0077.pdf"〉Seismic Velocities and Density of an Attenuating Earth〈/a〉〈br〉 (Hart, R. S., Anderson, D. L.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0078.pdf"〉A First-Motion Alternative to Geometrical Ray Theory〈/a〉〈br〉 (Chapman, C. H., Dey Sarkar, S. K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0079.pdf"〉Heterogeneous Velocity Structure at the Base of the Mantle〈/a〉〈br〉 (Snoke, J. A., Sacks, I. S.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0080.pdf"〉Heterogeneous velocity structure at the base of the mantle〈/a〉〈br〉 (Sacks, I. S., Snoke, J. A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0081.pdf"〉Theoretical Seismograms of Core Phases Calculated by a Frequency-Dependent Full Wave Theory, and Their Interpretation〈/a〉〈br〉 (Choy, G. L.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0082.pdf"〉Amplitudes of Long-Period PcP, SKS and SKKS and the Structure at the Base of the Mantle and in the Outer Core〈/a〉〈br〉 (Müller, G., Kind, R., Mula, A., Gregersen, S.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0083.pdf"〉Relative Errors in Group Velocity Measurements〈/a〉〈br〉 (Knopoff, L.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0084.pdf"〉The Propagation of Plasma Waves in the Jovian Magnetosphere〈/a〉〈br〉 (Denskat, K. U., Neubauer, F. M.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0085.pdf"〉Statistical Theory of Electromagnetic Induction in Thin Sheets〈/a〉〈br〉 (Treumann, R., Schäfer, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0086.pdf"〉Precursors to P' P' and Upper Mantle Discontinuities〈/a〉〈br〉 (Husebye, E. S., Haddon, R. A. W., King, D. W.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0090.pdf"〉Mantle Heterogeneity and Mislocation Patterns for Seismic Networks〈/a〉〈br〉 (Vermeulen, J. M., Doornbos, D. J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0093.pdf"〉Correlation Between Micro-Activity and Variation of Water Level at the Schlegeis-Reservoir〈/a〉〈br〉 (Blum, R., Bock, G., Fuchs, K., Merkler, G., Widmann, R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0095.pdf"〉Attenuation Coefficients of Acoustic Normal Modes in Shallow Water〈/a〉〈br〉 (Essen, H.-H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0096.pdf"〉Relation of Gravity to Elevation in Zambia〈/a〉〈br〉 (Töpfer, K. D.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0098.pdf"〉Albert Defant (1884 - 1974) 〈/a〉〈br〉 (Krauß, W.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0099.pdf"〉Study of the Structure of the Lower Lithosphere by Explosion Seismology in the USSR〈/a〉〈br〉 (Ryaboy, V. Z.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0102.pdf"〉P-Wave Amplitudes and Sources of Scattering in 〈i〉m〈/i〉〈sub〉b〈/sub〉-Observations〈/a〉〈br〉 (Ringdal, F.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0104.pdf"〉Analyse von Mikroseismikmessungen auf Sylt〈/a〉〈br〉 (Szelwis, R., Janle, P.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0107.pdf"〉Improved Technique for Rapid Interpretation of Gravity Anomalies Caused by Two-Dimensional Sedimentary Basins〈/a〉〈br〉 (Töpfer, K. D.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0109.pdf"〉Investigation of Isostasy by Computing the Correlation Coefficients between Elevations and Bouguer Anomalies〈/a〉〈br〉 (Janle, P.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0110.pdf"〉Geoelectrical Deep Soundings in Southern Africa Using the Cabora Bassa Power Line〈/a〉〈br〉 (Blohm, E. K., Worzyk, P., Scriba, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0112.pdf"〉Spectral Characteristics of Cross-Field and Two Stream Instability as Revealed by Rocket Borne Studies〈/a〉〈br〉 (Gupta, S. P.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0113.pdf"〉〈i〉Short Communication〈/i〉 Observation of PS Reflections from the Moho〈/a〉〈br〉 (Jacob, A. W. B., Booth, D. C.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0115.pdf"〉〈i〉Book Reviews〈/i〉〈/a〉〈br〉 (Makris, J., Weigel, W.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0116.pdf"〉Planetarische Dynamos〈/a〉〈br〉 (Stix, M.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0117.pdf"〉〈i〉Original Investigations〈/i〉 A Note on the Post-Rosenbluth Quasilinear Diffusion Coefficient in the Ring Current Region〈/a〉〈br〉 (Treumann, R., Grafe, A., Lehmann, H.-R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0118.pdf"〉Remote Sensing Experiment for Magnetospheric Electric Fields Parallel to the Magnetic Field〈/a〉〈br〉 (Wilhelm, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0119.pdf"〉A Study of the Echzell/Wetterau Earthquake of November 4, 1975〈/a〉〈br〉 (Neugebauer, H. J., Tobias, E.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0121.pdf"〉Thermoelastic Deformations of a Half-Space – A Green's Function Approach〈/a〉〈br〉 (Müller, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0123.pdf"〉Gravity Variations with Time in Northern Iceland 1965–1975〈/a〉〈br〉 (Torge, W., Drewes, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0125.pdf"〉High Resolution Near Surface Reflection Measurements Using a Vertical Array Technique〈/a〉〈br〉 (Schepers, R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0127.pdf"〉Ausbreitung von Rayleigh-Kanalwellen in Steinkohleflözen – Modellseismische Untersuchungen〈/a〉〈br〉 (Freystätter, S., Dresen, L.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0129.pdf"〉Comment on: Hydromagnetic Waves in a Non-Uniform Plasma〈/a〉〈br〉 (Kupfer, E.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0130.pdf"〉〈i〉Book Reviews〈/i〉〈/a〉〈br〉 (Kisslinger, C., Klußmann, J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0043/LOG_0131.pdf"〉〈i〉Erratum〈/i〉 Full Wave Theory Applied to a Discontinuous Velocity Increase: The Inner Core Boundary〈/a〉〈br〉 (Cormier, V. F., Richards, P. G.)〈/a〉〈/li〉 〈/body〉 〈/html〉

Beschreibung: Dynamo Theory

Beschreibung: research

Beschreibung: DFG, SUB Göttingen

Beschreibung: High-resolution seismic reflection, magnetic and gravity data, acquired offshore of Etna volcano, provide a new insight to understanding the relationship between tectonics and spatial-temporal evolution of volcanism. The Timpe Plateau, a structural high pertaining to the Hyblean foreland domain, located offshore of southeastern Mt. Etna, is speckled by volcanics and strongly affected by strike-slip tectonics. Transpressive deformation produced a push-up and a remarkable shortening along WNW-ESE to NW-SE trending lineaments. Fault segments, bounding basinal areas, show evidence of positive tectonic inversion, suggesting a former transtensive phase. Transtensive tectonics favoured the emplacement of deep magmatic intrusive bodies and Plio-Quaternary scattered volcanics through releasing zones. The continuing of wrench tectonics along different shear zones led to the migration of transtensive regions in the Etna area and the positive inversion of the former ones, where new magma ascent was hampered. This process caused the shifting of volcanism firstly along the main WNW-ESE trending "Southern Etna Shear Zone", then towards the Valle del Bove and finally up to the present-day stratovolcano.

Beschreibung: Published

Beschreibung: 12125

Beschreibung: 1T. Struttura della Terra

Beschreibung: 1V. Storia eruttiva

Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani

Beschreibung: 1A. Geomagnetismo e Paleomagnetismo

Beschreibung: 3A. Geofisica marina e osservazioni multiparametriche a fondo mare

Beschreibung: 2TR. Ricostruzione e modellazione della struttura crostale

Beschreibung: JCR Journal

Beschreibung: Global cloud-resolving models (GCRMs) are a new category of atmospheric global models designed to solve different flavors of the nonhydrostatic equations through the use of kilometer-scale global meshes. GCRMs make it possible to explicitly simulate deep convection, thereby avoiding the need for cumulus parameterization and allowing for clouds to be resolved by microphysical models responding to grid-scale forcing. GCRMs require high-resolution discretization over the globe, for which a variety of mesh structures have been proposed and employed. The first GCRM was constructed 15 years ago, and in recent years, other groups have also begun adopting this approach, enabling the first intercomparison studies of such models. Because conventional general circulation models (GCMs) suffer from large biases associated with cumulus parameterization, GCRMs are attractive tools for researchers studying global weather and climate. In this review, GCRMs are described, with some emphasis on their historical development and the associated literature documenting their use. The advantages of GCRMs are presented, and currently existing GCRMs are listed and described. Future prospects for GCRMs are also presented in the final section.

Beschreibung: The InSight spacecraft was proposed to be a build-to-print copy of the Phoenix vehicle due to the knowledge that the lander payload would be similar and the trajectory would be similar. However, the InSight aerothermal analysts, based on tests performed in CO2 during the Mars Science Laboratory mission (MSL) and completion of Russian databases, considered radiative heat flux to the aftbody from the wake for the first time for a US Mars mission. The combined convective and radiative heat flux was used to determine if the as-flown Phoenix thermal protection system (TPS) design would be sufficient for InSight. All analyses showed that the design would be adequate. Once the InSight lander was successfully delivered to Mars on November 26, 2018, work began to reconstruct the atmosphere and trajectory in order to evaluate the aerothermal environments that were actually encountered by the spacecraft and to compare them to the design environments.The best estimated trajectory (BET) reconstructed for the InSight atmospheric entry fell between the two trajectories considered for the design, when looking at the velocity versus altitude values. The maximum heat rate design trajectory (MHR) flew at a higher velocity and the maximum heat load design trajectory (MHL) flew at a lower velocity than the BET. For TPS sizing, the MHL trajectory drove the design. Reconstruction has shown that the BET flew for a shorter time than either of the design environments, hence total heat load on the vehicle should have been less than used in design. Utilizing the BET, both DPLR and LAURA were first run to analyze the convective heating on the vehicle with no angle of attack. Both codes were run with axisymmetric, laminar flow in radiative equilibrium and vibrational non-equilibrium with a surface emissivity of 0.8. Eight species Mitcheltree chemistry was assumed with CO2, CO, N2, O2, NO, C, N, and O. Both codes agreed within 1% on the forebody and had the expected differences on the aftbody. The NEQAIR and HARA codes were used to analyze the radiative heating on the vehicle using full spherical ray-tracing. The codes agreed within 5% on most aftbody points of interest.The LAURA code was then used to evaluate the conditions at angle of attack at the peak heating and peak pressure times. Boundary layer properties were investigated to confirm that the flow over the forebody was laminar for the flight.Comparisons of the aerothermal heating determined for the reconstructed trajectory to the design trajectories showed that the as-flown conditions were less severe than design

Beschreibung: A series of eight olivine specimens were fabricated by hot-pressing at 1200 degrees Celsius and 300 megapascals (MPa). Each hot-pressed specimen was then wrapped in Pt, Ni or NiFe foil to vary oxygen fugacity (fO2), and interrogated via forced torsional oscillation. Mechanical testing was conducted at 10 oscillation periods between 1 and 1000 seconds, at a confining pressure of 200 MPa, during a slow staged-cooling from a maximum temperature of 1200 degrees Celsius to room temperature. After mechanical testing, each specimen was axially sectioned and EBSD (Electron BackScatter Diffraction) was used for the determination of the representative grain size, and grain size distribution of each sample. In addition, each longitudinal section was mapped via FTIR (Fourier Transform InfraRed spectroscopy) to determine the spatial distribution and concentrations of chemically bound and molecular water. Amongst these specimens, chemically bound water contents were observed to vary between 0 and 1150 atom ppm (parts per million) H/Si, and molecular water concentrations varied between 0 and 245 atom ppm H/Si. Our forced-oscillation results demonstrate that the measured magnitude of anelastic relaxation within the experimental window of oscillation periods is unrelated to the water content. Rather, a relationship was observed between the magnitude of anelastic relaxation and the prevailing redox conditions, which is influenced by the choice of metal sleeving used during the mechanical test. Further, regardless of water content or metal sleeving, each specimen exhibits coupled variations in shear modulus and dissipation within the observational window, indicative of high-temperature background behavior, that can be described by a Burgers-type model. During initial fitting of the Burgers models, the unrelaxed shear modulus at a reference temperature of 900 degrees Celsius (G (sub UR)) and the temperature derivative of the unrelaxed shear modulus (dG (sub U)/dT), were treated as adjustable parameters. For all Fe-bearing olivine samples (but not a hydrous and oxidized Fe-free sample) we observe deficits of G (sub UR), and increased values of dG (sub U)/dT, relative to the expected elastic (anharmonic) behavior of Fo90 olivine. This behavior is indicative of anelastic relaxation occurring at shorter periods than observable within the window of oscillation periods used in the mechanical test. Moving towards a comprehensive seismologically applicable Burgers model, which includes this newly observed effect of redox conditions on anelastic relaxation, we will present our progress in reconciling truly anharmonic and elastic behavior of Fo (sub 90) olivine with our observed forced-oscillation data.

Beschreibung: Improvements and results of a new method are presented that computes a pre-test estimate of the precision error of the drag coefficient of a wind tunnel model. The error estimate is defined as the part of the drag coefficient's precision error that is primarily associated with the precision error of the angle of attack measurement and physical characteristics of the chosen strain-gage balance. The method indirectly describes the precision error of the angle of attack measurement by using an assumed balance gage output variation of one microV/V. The physical characteristics of the balance, on the other hand, are described by partial derivatives of the axial and normal forces with respect to the strain-gage outputs. These derivatives can directly be obtained from the data reduction matrix of the balance. The precision error estimate itself is calculated by applying a simple explicit equation that uses the model reference area, the dynamic pressure, the angle of attack, the coefficients of the linear terms of the data reduction matrix, and the electrical output variation of one microvolt per volt as input. Precision errors at constant angle of attack may be visualized as contour plots by plotting them, for example, versus the Mach number and the total pressure. Characteristics of NASA's MC60E balance are used in combination with the reference area of a generic wind tunnel model in order to demonstrate that error estimates are independent of both the balance load format and the units chosen for the description of balance loads, model reference area, and the dynamic pressure. Finally, experimental data from a wind tunnel test of the Ames Check Standard Model in the NASA Ames 11-foot Transonic Wind Tunnel illustrates the application of the method to real-world test data.

Beschreibung: Wake vortex spacing standards constrict the terminal area throughput and impose severe constraints on the overall capacity and efficiency of the National Airspace System. For more than two decades starting in the early 1990s, the National Aeronautics and Space Administration conducted extensive research on characterizing the formation and evolution of aircraft wakes. This multidisciplinary work included comprehensive field experiments (Pruis et al. 2016), flight tests (Vicroy et al. 1998), and wind tunnel tests (Rossow 1994; Chow et al. 1997). Parametric studies using large eddy simulations (Proctor 1998; Proctor et al. 2006) were conducted in order to develop fast-time models for the prediction of wake transport and decay (Ahmad et al. 2016). Substantial effort was spent on the formulation of acceptable vortex hazard metrics (Tatnall 1995; Hinton and Tatnall 1997). Several wake encounter severity metrics have been suggested in the past, which include the wake circulation strength, vortex-induced rolling moment coefficient (Clv), bank angle, and the roll control ratio (Tatnall 1995; Hinton and Tatnall 1997; Van der Geest 2012). The vortex-induced rolling moment coefficient introduced by Bowles and Tatnall (Tatnall 1995; Gloudemans et al. 2016) has been used extensively for risk and safety analysis of newly proposed air traffic management concepts and procedures. The original method of Bowles and Tatnall assumed a constant wing loading (the wing lift-curve slope, CL is constant), which resulted in an overestimation of the vortexinduced rolling moment coefficient. Bowles (2014) suggested a correction to the original method that provides more accurate values of Clv and which is also consistent with the underlying physics of the problem. The overestimation of Clv in the original method can be corrected by assuming an elliptical lift distribution. Figure 1.1 illustrates the correction in Clv achieved by the modified method.

Beschreibung: Since its development by Wark and Watson (2006), the Ti-in-quartz geothermometer (TitaniQ) has been continuously refined and applied to a variety of lithologies from different crustal settings. Assuming quartz crystallized and incorporated Ti under equilibrium conditions and providing TiO2 activity (alpha (sub TiO2)) is reasonably constrained, crystallization temperatures at typical crustal pressures can be calculated. In turn, when crystallization temperatures are independently constrained, Ti-in-quartz can be used as a geobarometer. Here we explore the application of this technique to impact lithologies. Quartz is ubiquitous in terrestrial impact structures in upper crustal settings and can also form as a post-impact hydrothermal mineral. Together with other geothermometers, such as Ti-in-zircon, Ti-in-quartz can potentially help constrain the temperature-pressure conditions during the formation of the pre-impact target rock at terrestrial impact structures, as well as impact-produced and hydrothermally-altered lithologies. This work presents the first systematic Ti-in-quartz study of impactites and granitoid target rocks from the approximately180-kilometer-diameter, end-Cretaceous Chicxulub crater on the Yucatan Peninsula, Mexico, thereby placing new constraints on the emplacement of felsic plutons within the Maya Block in the Paleozoic, impact melt crystallization at approximately 66 Ma (million years ago), and post-impact hydrothermal overprint inside the Chicxulub crater.

Beschreibung: National airspace, the management for access and operation of these vehicles is required. This management is being developed under the unmanned aircraft system traffic management system (UTM) program. To determine the aerodynamic characteristics of drones, wind tunnel experiments and computation fluid dynamic (CFD) analysis have been conducted. These experiments and analyses are undertaken to understand the flight capabilities of these vehicles in variable head and cross wind conditions. The results of these investigations will provide metrics for the safe operation of these vehicles in and around civil populations and in urban settings. The focus of this paper is to model a drone installed in a wind tunnel for varying pitch attitudes and rotor rpm settings. Specifically, the IRIS drone is modeled in the NASA-Ames 7x10 ft. W/T. The tunnel mounting hardware and the tunnel enclosure are modeled with the IRIS drone geometry. The rotors of the drone are modeled using two methodologies: a rotor disk model and individual blade representations. The results of the analysis are compared with available experimental data to validate the computational approach.

Beschreibung: The Mid-Lift-to-Drag ratio Rigid Vehicle (MRV) is a candidate in the NASA multi-center effort to determine the most cost effective vehicle to deliver a large-mass payload to the surface of Mars for a human mission. Products of this effort include six-degree-of-freedom (6DoF) entry-to-descent trajectory performance studies for each candidate vehicle. These high fidelity analyses help determine the best guidance and control (G&C) strategies for a feasible, robust trajectory. This paper presents an analysis of the MRV's G&C design by applying common entry and descent associated uncertainties using a Fully Numerical Predictor-corrector Entry Guidance (FNPEG) and tunable Apollo powered descent guidance.

Beschreibung: Artificial ice shapes of various geometric fidelity were tested on a wing model based on the Common Research Model. Low Reynolds number test were conducted at Wichita State University's Walter H. Beech Memorial Wind utilizing an 8.9% scale model, and high Reynolds number tests were conducted at ONERA's F1 wind tunnel utilizing a 13.3% scale model. Several identical geometrically-scaled ice shapes were tested at both facilities, and the results were compared at overlapping Reynolds and Mach numbers. This was to ensure that the results and trends observed at low Reynolds number could be applied and continued to high, near-flight Reynolds number. The data from Wichita State University and ONERA F1 agreed well at matched Reynolds and Mach numbers. The lift and pitching moment curves agreed very well for most configurations. This confirmed results from previous tests with other ice shapes that indicated the data from the low Reynolds number tests could be used to understand ice-swept-wing aerodynamics at high Reynolds number. This allows ice aerodynamics testing to be performed at low Reynolds number facilities with much lower operating costs and generate results that are applicable to flight Reynolds number.

Beschreibung: The history of the Greenland Ice Sheet has been influenced by the geodynamic response to ice sheet fluctuations, and this interaction may help explain past deglaciations under modest climate forcing. We hypothesize that when the Iceland hot spot passed beneath northcentral Greenland, it thinned the lithosphere and left anomalous heat likely with partially melted rock; however, it did not break through the crust to supply voluminous flood basalts. Subsequent PlioPleistocene glacialinterglacial cycles caused large and rapidly migrating stresses, driving dike formation and other processes that shifted melted rock toward the surface. The resulting increase in surface geothermal flux favored a thinner, fasterresponding ice sheet that was more prone to deglaciation. If this hypothesis of control through changes in geothermal flux is correct, then the longterm (10 (sup 5) to 10 (sup 6) years) trend now is toward lower geothermal flux, but with higherfrequency (less than or equal to 10( sup 4) to 10 (sup 5) years) oscillations linked to glacialinterglacial cycles. Whether the geothermal flux is increasing or decreasing now is not known but is of societal relevance due to its possible impact on ice flow. We infer that projections of the future of the ice sheet and its effect on sea level must integrate geologic and geophysical data as well as glaciological, atmospheric, oceanic, and paleoclimatic information.

Beschreibung: The intermediate wakes of thin flat plates with circular trailing edges (TEs) are investigated here with direct numerical simulations (DNSs). The separating boundary layers are turbulent in all cases. The near wake in two thin-plate cases (IN & NS), with a focus on the vortex shedding process, was explored in a recent article. Intermittent shedding was observed in Case IN. Case NS, with half the TE diameter of Case IN, was an essentially non-shedding case. A third case (ST) with a sharp trailing edge was also investigated and found to exhibit an intermittent wake instability. The objectives of the present study are twofold. The first is to determine if the wake instability found in Case ST exists in Cases IN and NS as well. The second is to provide the distributions of the turbulent normal intensities and shear stress in the wake and to understand these distributions via the budget terms in the corresponding transport equations. The results show that both Cases IN & NS exhibit a wake instability in the intermediate wake region, that is similar to that found earlier in Case ST. We note that in Case IN, the presence of an intermediate-wake instability results in the co-existence of two different types of instability within a single wake. The distributions of the turbulent normal intensities and shear stress, and the budget terms for the streamwise intensity are included and discussed here. All the budget terms contribute appreciably to the overall budget in the transport equation for streamwise normal intensity.

Beschreibung: US Army MC-4/5 ram-air parachutes were tested in the 80- by 120-Ft test section of the National Full-Scale Aerodynamics Complex. Arrays of targets on the upper and lower surfaces of the central cell of the canopies were measured by stereo photogrammetry, and the target positions were used to estimate both the shape of the cell and angle of attack of the canopy. Forces and moments were measured by a six-axis load cell. Based on the photogrammetry and load-cell measurements, the relationships between lift, drag, and angle of attack were determined over a range of trailing-edge flap deflections, front riser lengths, and free-stream airspeeds. This paper describes the test, with an emphasis on the photogrammetry measurements, and presents a summary of results.

Beschreibung: The Advanced Supersonic Parachute Inflation Research Experiments (ASPIRE) project waslaunched to develop the capability for testing supersonic parachutes at Mars-relevant conditions.Three initial parachute tests, targeted as a risk-reduction activity for NASA's upcomingMars2020 mission, successfully tested two candidate parachute designs and provided valuabledata on parachute inflation, forces, and aerodynamic behavior. Design of the flight tests dependedon flight mechanics simulations which in turn required aerodynamic models for the payload, andthe parachute. Computational Fluid Dynamics (CFD) was used to generate these models preflightand are compared against the flight data after the tests. For the payload, the reconstructedaerodynamic behavior is close to the pre-flight predictions, but the uncertainties in thereconstructed data are high due to the low dynamic pressures and accelerations during the flightperiod of comparison. For the parachute, the predicted time to inflation agrees well with the preflightmodel; the peak aerodynamic force and the steady state drag on the parachute are withinthe bounds of the pre-flight models, even as the models over-predict the parachute drag atsupersonic Mach numbers. Notably, the flight data does not show the transonic drag decreasepredicted by the pre-flight model. The ASPIRE flight tests provide previously unavailablevaluable data on the performance of a large full-scale parachute behind a slender leading bodyat Mars-relevant Mach number, dynamic pressure and parachute loads. This data is used topropose a new model for the parachute drag behind slender bodies to aid future experiments.

Beschreibung: Objectives: Reliable evaluation of mass flow rates through permeable boundaries - Estimate and control discretization error- Consider both computational domain outflow and inflow- Applicable to simulating propulsion-system effects, as well as secondary flow paths - Explore feasibility of handling more general outputs at domain boundaries. Design optimization subject to mass-flow-rate constraints - Improve aerodynamic performance and reduce noise due to sonic boom - Control discretization error in design space to improve confidence in final designs.

Beschreibung: Studies of many objects in petrographic thin section, such as melt inclusions in igneous rocks, chondrules and Ca-Al rich inclusions in chondritic meteorites, or clasts in lunar and other breccias, require or can benefit from knowledge of their bulk compositions. Given the scarcity of these materials, the reluctance of curators to provide more abundant material, and the extreme difficulty of cleanly separating such objects from their rock matrices, geochemical and cosmochemical studies need the ability to determine their bulk compositions from in situ methods, such as defocused beam analysis, or quantitative chemical mapping by electron beam methods.

Beschreibung: A group called as Martian meteorites is composed of shergottites, nakhlites, chassignites, and orthopyroxenite, and they are thought to be derived from Mars. Among the Martian meteorites nakhlites and chassignites show similar cosmic-ray exposure (CRE) ages of 11-12 million years, although petrologic characteristics are very different between them. Both nakhlites and chassignites indicate similar cooling rates, and would have cooled in identical scale of igneous bodies. However, the relationship between nakhlites and chassignites is still unclear, although they might have ejected at the same time, i.e., by accidentally coincidental impact events which occurred at different places on Mars or by a single impact which excavated both nakhlites and chassignites residing in a relatively small area. Here we propose that the chassignites show a genetically close relationship with nakhlites, i.e., both groups could be located within a relatively narrow area from where a single impact could have launched those meteorites, based on noble gas data obtained in our laboratory. If chassignites were really ejected with nakhlites by a single impact, both types of meteorites will provide us with geological/petrological profile in the area where both pyroxene-rich lava (nakhlites) and dunite-rich rocks (chassignites) are located close to the Martian surface. [i.e. discusses NWA 2737, etc. (Martian meteorites that fell in Northwest Africa)]

Beschreibung: Eight olivine specimens were fabricated by use of a solgel method and hot-pressing at 1200 degrees Centigrade and 300 megapascals (MPa) inside of welded Pt capsules. Each hot-pressed specimen was then recovered, precision ground, and wrapped in Pt, Ni or NiFe foil to vary oxygen fugacity (fO2) during the subsequent forced torsional oscillation measurements. Mechanical testing was conducted at 10 oscillation periods between 1 and 1000 seconds, at a confining pressure of 200 MPa, during a slow staged-cooling from a maximum temperature of 1200 degrees Centigrade down to room temperature. After mechanical testing, each specimen was axially sectioned and EBSD (Electron BackScatter Diffraction) was used for the determination of the representative grain size, and grain size distribution of each sample. In addition, each longitudinal section was mapped via FTIR (Fourier Transform Infrared Spectroscopy) to determine the spatial distribution and concentrations of chemically bound and molecular water. Amongst these eight specimens, chemically bound water contents were observed to vary between 0 and 1150 atom parts per million (ppm) H/Si, and molecular water concentrations varied between 0 and 245 atom ppm H/Si. Our forced-oscillation results demonstrate that the measured magnitude of anelastic relaxation within the experimental window of oscillation periods is unrelated to the water content. Rather, a relationship was observed between the magnitude of anelastic relaxation and the prevailing redox conditions, which is influenced by the choice of metal sleeving used during the mechanical test. Further, regardless of water content or metal sleeving, each specimen exhibits coupled variations in shear modulus and dissipation within the observational window, indicative of high-temperature background behavior, that can be described by a Burgers-type model. During initial fitting of the Burgers models, the unrelaxed shear modulus at a reference temperature of 900C (elastic unloading/reloading shear modulus G (sub UR)) and the temperature derivative of the unrelaxed shear modulus (dGU/dT), were treated as adjustable parameters. For all Fe-bearing olivine samples we observe deficits of G (sub UR) and increased values of dGU/dT, relative to the expected elastic (anharmonic) behavior for Fo (Forsterite content percentage) (sub 90) olivine. This behavior is indicative of anelastic relaxation occurring at shorter periods than observable within the window of oscillation periods used in the mechanical test. Moving towards a comprehensive and seismologically applicable Burgers model, which includes this newly observed effect of redox conditions on anelastic relaxation, we will present our progress on reconciling truly anharmonic and elastic behavior of Fo (sub 90) olivine with our observed forced-oscillation data.

Beschreibung: The observed Earth's polar motion on decadal time scales has long been conjectured to be excited by the exchange of equatorial angular momentum between the solid mantle and the fluid outer core, via the mechanism of electromagnetic (EM) core-mantle coupling. However, past estimations of the EM coupling torque from surface geomagnetic observations is too weak to account for the observed decadal polar motion. Our recent estimations from numerical geodynamo simulations have shown the opposite. In this paper, we re-examine in detail the EM coupling mechanism and the properties of the magnetic field in the electrically conducting lower mantle (characterized by a thin D-layer at the base of the mantle). Our simulations find that the toroidal field in the D-layer from the induction and convection of the toroidal field in the outer core could be potentially much stronger than that from the advection of the poloidal field in the outer core. The former, however, cannot be inferred from geomagnetic observations at the Earth's surface, and is missing in previous EM torque estimated from geomagnetic observations. Our deduction suggests further that this field could make the actual EM coupling torque sufficiently strong, at approximately 5 10(exp 19) Nm, to excite, and hence explain, the decadal polar motion to magnitude of approximately 10 mas.

Beschreibung: The observation that arc magmas are the most oxidized on Earth have led petrologists to question whether the subduction process might cause oxidation of the sub-arc mantle source. A strong correlation between the input of slab-derived aqueous fluid and Fe3(+)/Fe in arc magmas has led to the hypothesis that slab fluids may facilitiate the transfer of redox potential from oxidized slab material to mantle wedge and subsequently to primary arc melts. Despite this intuitive link, identifying an efficient and ubiquitous chemical process to transfer oxidation state in slab fluids has been challenging. Pure H2O alone is an inefficient oxidizer in the mantle, necessitating another oxidant within the fluid. Commonly invoked components include S or C, which are likely heterogeneously distributed within subducting slabs, and direct transfer of Fe3(+), which is only possible in very solute-rich fluids. Here we present a new mechanism to explain the oxidation of the sub-arc mantle by slab-derived aqueous fluid, wherein dissolved H(+)(aq) is reduced to H2(aq). Redox equilibrium is satisfied by electron transfer from Fe2(+)(s), which is oxidized in the rock to Fe3(+)(s) in the reaction: 2Fe2(+)(s) + 2H(+)(aq) = 2Fe3(+)(s) + H2(aq). This simple reaction was previously overlooked due to the assumption that all H must be bound by H2O molecules (i.e., no dissolved H), applicable to a pure H2O fluid, but not one with a solute load as addressed here. The application of thermodynamic modeling tools from aqueous geochemistry (DEW, EQ3/6) to mantle petrology predicts this reaction between mantle rock and slab fluid with our own experimentally constrained chemistry and fO2 (QFM+2). Mass transfer model results show an increase in Fe3(+)/Fe in mantle rock from MORB- like (0.15) to arc-like (0.20.3) values at reasonable fluid fluxes, co-incident with increasing H2 activity in the fluid. This can explain the stark correlation between slab fluid input into the mantle wedge and the observed fO2 of arc magmas. Moreover, it does not require diffusion of hydrogen out of the system. Instead, H2 remains dissolved in fluid in equilibrium with oxidized mantle rock.

Beschreibung: The experimental, fully electric X-57 Maxwell is designed to enable lower energy con-sumption at cruise compare to a fuel burning baseline. This is to be achieved using a sumof subsystem benefits incorporated in the electric, airframe, and propulsion systems. AMission Planning Tool captures the three stages of X-57 development in order to assess thedesign of each subsystem in the context of the whole aircraft. The Mission Planning Toolfor the fully electric X-57 Maxwell captures the aerodynamics, propulsion, heat transfer,and power system of the aircraft with trajectory optimization capabilities. It is able tomodel these subsystems through all phases of flight, from taxi to landing. Through thismultidisciplinary approach, we are able to predict the benefit of each subsystem and theeffect of key design assumptions and how the aircraft will react if they are not met or ex-ceeded. As the aircraft progresses and systems are tested, we can use the Mission PlanningTool to continue to predict performance. This paper details the continued development ofthe X-57 Mission Planning Tool and demonstrates its capabilities.

Beschreibung: Compound extremes such as cooccurring soil drought (low soil moisture) and atmospheric aridity (high vapor pressure deficit) can be disastrous for natural and societal systems. Soil drought and atmospheric aridity are 2 main physiological stressors driving widespread vegetation mortality and reduced terrestrial carbon uptake. Here, we empirically demonstrate that strong negative coupling between soil moisture and vapor pressure deficit occurs globally, indicating high probability of cooccurring soil drought and atmospheric aridity. Using the Global Land Atmosphere Coupling Experiment (GLACE)-CMIP5 experiment, we further show that concurrent soil drought and atmospheric aridity are greatly exacerbated by land atmosphere feedbacks. The feedback of soil drought on the atmosphere is largely responsible for enabling atmospheric aridity extremes. In addition, the soil moistureprecipitation feedback acts to amplify precipitation and soil moisture deficits in most regions. CMIP5 models further show that the frequency of concurrent soil drought and atmospheric aridity enhanced by landatmosphere feedbacks is projected to increase in the 21st century. Importantly, land atmosphere feedbacks will greatly increase the intensity of both soil drought and atmospheric aridity beyond that expected from changes in mean climate alone.

Beschreibung: Atmospheric motion vectors (AMVs), derived by tracking patterns, represent the winds in a layer characteristic of the pattern. AMV height (or pressure), important for applications in atmospheric research and operational meteorology, is usually assigned using observed IR brightness temperatures with a modeled atmosphere and can be inaccurate. Stereoscopic tracking provides a direct geometric height measurement of the pattern that an AMV represents. We extend our previous work with multi-angle imaging spectroradiometer (MISR) and GOES to moderate resolution imaging spectroradiometer (MODIS) and the GOES-R series advanced baseline imager (ABI). MISR is a unique satellite instrument for stereoscopy with nine angular views along track, but its images have a narrow (380 km) swath and no thermal IR channels. MODIS provides a much wider (2330 km) swath and eight thermal IR channels that pair well with all but two ABI channels, o e ring a rich set of potential applications. Given the similarities between MODIS and VIIRS, our methods should also yield similar performance with VIIRS. Our methods, as enabled by advanced sensors like MODIS and ABI, require high-accuracy geographic registration in both systems but no synchronization of observations. AMVs are retrieved jointly with their heights from the disparities between triplets of ABI scenes and the paired MODIS granule. We validate our retrievals against MISR-GOES retrievals, operational GOES wind products, and by tracking clear-sky terrain. We demonstrate that the 3D-wind algorithm can produce high-quality AMV and height measurements for applications from the planetary boundary layer (PBL) to the upper troposphere, including cold-air outbreaks, wildfire smoke plumes, and hurricanes.

Beschreibung: NASAs Advanced Air Transport Technology (AATT) project is investigating boundary layer ingesting (BLI) propulsors for advanced subsonic commercial vehicle concepts to enable the reduction of fuel burn. A multidisciplinary team of researchers from NASA, United Technologies Research Center (UTRC), Virginia Polytechnic University, and the Air Force Arnold Engineering Development Complex developed and tested an embedded BLI inlet and distortion-tolerant fan (BLI2DTF) system in the NASA Glenn Research Center (GRC) 8- foot by 6-foot (8x6) transonic wind tunnel. The test demonstrated the component performance goals necessary for an overall fuel burn reduction of 3 to 5 percent on a large hybrid wing body (HWB) aircraft. Special test equipment, including a raised floor with flow effectors and a bleed system, was developed for use in the 8x6 to produce the appropriate incoming boundary layer representative of an HWB application. Detailed measurements were made to determine the inlet total pressure loss and distortion, fan stage efficiency, and aeromechanic performance including blade vibration stress and displacement response. Results from this test were used as input to a vehicle-level system study performed by the AATT project to assess the impact of BLI on an alternative advanced concept aircraft referred to as the NASA D8 (ND8), which is somewhat similar to the HWB in its integration of the propulsor. This paper will provide an overview of the project timeline, special test equipment needed in the wind tunnel to develop the appropriate incoming boundary layer, and the difficulties in designing a propulsor for the test. The paper will conclude with some representative aerodynamic and aeromechanic data from the test itself and conclude with how this data was used in the ND8 system study.

Beschreibung: This manual describes the installation and execution of FUN3D version 13.6, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

Beschreibung: _NASA's Advanced Air Transport Technology (AATT) project is investigating boundary layer ingesting (BLI) propulsors for advanced subsonic commercial vehicle concepts to enable the reduction of fuel burn. A multidisciplinary team of researchers from NASA, United Technologies Research Center (UTRC), Virginia Polytechnic University, and the Air Force Arnold Engineering Development Complex developed and tested an embedded BLI inlet and distortion-tolerant fan (BLI2DTF) system in the NASA Glenn Research Center (GRC) 8-foot by 6-foot (8x6) transonic wind tunnel. The test demonstrated the component performance goals necessary for an overall fuel burn reduction of 3 to 5 percent on a large hybrid wing body (HWB) aircraft. Special test equipment, including a raised floor with flow effectors and a bleed system, was developed for use in the 8x6 to produce the appropriate incoming boundary layer representative of an HWB application. Detailed measurements were made to determine the inlet total pressure loss and distortion, fan stage efficiency, and aeromechanic performance including blade vibration stress and displacement response. Results from this test were used as input to a vehicle-level system study performed by the AATT project to assess the impact of BLI on an alternative advanced concept aircraft referred to as the NASA D8 (ND8), which is somewhat similar to the HWB in its integration of the propulsor. This paper will provide an overview of the project timeline, special test equipment needed in the wind tunnel to develop the appropriate incoming boundary layer, and the difficulties in designing a propulsor for the test. The paper will conclude with some representative aerodynamic and aeromechanic data from the test itself and conclude with how this data was used in the ND8 system study.

Beschreibung: Thermal Protection System (TPS) modeling requires accurate representation and prediction of the thermomechanical behavior of ablative materials. State-of-the-art TPS materials such as Phenolic Impregnated Carbon Ablator (PICA) have a proven flight record and demonstrate exceptional capabilities for handling extreme aerothermal heating conditions. The constant push for lightweight materials that are flexible in their design and performance, and hence allow for a wide range of mission profiles, has led NASA over the past years to develop its Heatshield for Extreme Entry Environment Technology (HEEET). HEEET is based primarily on a dual layer woven carbon fiber architecture and the technology has successfully been tested in arc-jet facilities. These recent developments have sparked interest in the accurate micro-scale modeling of composite weave architectures, to predict the structural response of macro-scale heatshields upon atmospheric entry. This effort can be extended to incorporate in-depth failure mechanics analyses as a result of local thermal gradients or high-velocity particle impact.

Beschreibung: We present the first quantitative calculations of thermospheric heating and cooling times for geomagnetic storms of different intensity, including extreme events. We utilize the neutral mass density database of the CHAllenging Minisatellite Payload and Gravity Recovery And Climate Experiment missions to produce thermospheric global system response to geomagnetic storms caused by coronal mass ejections via superposed epoch analysis during May 2001 to December 2015. Storm events are grouped in five different categories based on the minimum value of the SYMH index. We calculate the time from storm onset for the thermosphere to reach maximum intensification (heating time) and the time from onset for the thermosphere to recover (cooling time). We find that heating and cooling times decrease as storm intensity increases and the effect is more pronounced for the cooling times. For extreme storms, the thermospheric heating time is 9.5 hr, while the cooling time is 22 hr.

Beschreibung: NASA successfully demonstrated next generation SLR, VLBI, and GNSS using the GGAO prototypes.Tier 1 deployment of next generation stations is underway: KPGO (Kokee Park, Hawaii); VGOS station operational; VGOS station at McDonald Observatory, Texas nearly operational; build of long-lead items for first 3 SLR stations underway. Planning and discussions with international partners for Tier 2 deployment underway. Plan for Decadal Survey responsive deployment acceleration under review by NASA.

Beschreibung: Prediction and control of the onset of transition and the associated variation in aerothermodynamic parameters in high-speed flows is key to optimize the performance and design of Thermal Protection Systems (TPS) of next-generation aerospace vehicles [1]. Boundary Layer Transition (BLT) characteristics can influence the surface heating budget determining the TPS thickness and consequently its weight penalty. Ablative heatshields are designed to alleviate the high heat flux at the surface through pyrolysis of their polymeric matrix and subsequent fiber ablation [2]. Pyrolysis leads to out-gassing and non-uniform ablation lead to surface roughness, both of which are known to influence the transition process. An ablator impacts BLT through three main routes: gas injecting into the boundary layer from the wall, changing the surface heat transfer due to wall-flow chemical reactions, and modifying surface roughness [3]. In preparation to Mars 2020 mission post-flight analysis, the predictive transition capability has been initiated toward hard-coupling porous material response analysis and aerothermal environment calculation.

Beschreibung: The Mars Science Laboratory (MSL) Entry, Descent and Landing Instrumentation (MEDLI) collected in-flight data largely used by the ablation community to verify and validate physics-based models for the response of the Phenolic Impregnated Carbon Ablator (PICA) material [1-4]. MEDLI data were recently used to guide the development of NASAs high-fidelity material response models for PICA, implemented in the Porous material Analysis Toolbox based on OpenFOAM (PATO) software [5-6]. A follow-up instrumentation suite, MEDLI2, is planned for the upcoming Mars 2020 mission [7] after the large scientific impact of MEDLI. Recent analyses performed as part of MEDLI2 development draw the attention to significant effects of a protective coating to the aerothermal response of PICA. NuSil, a silicone-based overcoat sprayed onto the MSL heatshield as contamination control, is currently neglected in PICA ablation models. To mitigate the spread of phenolic dust from PICA, NuSil was applied to the entire MSL heatshield, including the MEDLI plugs. NuSil is a space grade designation of the siloxane copolymer, primarily used to protect against atomic oxygen erosion in the Low Earth Orbit environment. Ground testing of PICA-NuSil (PICA-N) models all exhibited surface temperature jumps of the order of 200 K due to oxide scale formation and subsequent NuSil burn-off. It is therefore critical to include a model for the aerothermal response of the coating in ongoing code development and validation efforts.

Beschreibung: Methane is a potent greenhouse gas, but a complete accounting of global methane sources and sinks is still ongoing. Sediments beneath glaciers and ice sheets harbour carbon reserves that, under certain conditions, can be converted to methane. However, the formation and release of such methane is an unquantified component of the arctic methane budget. Lamarche-Gagnon et al. present direct measurements of dissolved methane in proglacial discharge from a land-terminating glacier of the Greenland Ice Sheet. This proglacial discharge was supersaturated with methane and had diffusive methane fluxes similar to other terrestrial rivers for the duration of the summer measurement period. Their results suggest that variability in proglacial discharge is associated with methane release from subglacial environments, implicating both the form and evolution of the subglacial hydrologic system as a newly discovered control in the arctic methane cycle.The study by Lamarche-Gagnon et al. is an important example of how the cryosphere can interact with the surrounding Earth system in unexpected and potentially significant ways. Characterizing the ability of subglacial sediments to convert and store methane and the ability of the subglacial hydrologic system to export this methane to the atmosphere, through both modeling and observational studies, are critical steps in improving our knowledge of the sources and sinks of arctic methane and better constraining their future changes.

Beschreibung: Magnetic reconnection in a quasiparallel bow shock is investigated with twodimensional local particleincell simulations. In the shock transition and downstream regions, large amplitude magnetic fluctuations exist, and abundant current sheets form. In some current sheets, reconnection occurs, and ionscale and electronscale magnetic islands are generated. In electronscale island regions, only electron outflow jets are observed, producing a quadrupolar outofplane magnetic field pattern, while in ionscale islands, both ions and electrons are involved and energized in reconnection. Normalized reconnection rates are obtained to be between around 0.1 to 0.2, and particle acceleration signatures are seen in distribution functions.

Beschreibung: No abstract available

Beschreibung: Kinetic structures of electron diffusion regions (EDRs) under finite guide fields in magnetotail reconnection are reported. The EDRs with guide fields 0.140.5 (in unit of the reconnecting component) are detected by the Magnetospheric Multiscale spacecraft. The key new features include the following: (1) cold inflowing electrons accelerated along the guide field and demagnetized at the magnetic field minimum while remaining a coherent population with a low perpendicular temperature, (2) wave fluctuations generating strong perpendicular electron flows followed by alternating parallel flows inside the reconnecting current sheet under an intermediate guide field, and (3) gyrophase bunched electrons with high parallel speeds leaving the Xline region. The normalized reconnection rates for the three EDRs range from 0.05 to 0.3. The measurements reveal that finite guide fields introduce new mechanisms to break the electron frozenin condition.

Beschreibung: NASA is investigating the potential of integrating acoustic liners into fan cases to reduce fan noise, while maintaining the fans aerodynamic performance. An experiment was conducted to quantify the aerodynamic impact of circumferentially grooved fan cases with integrated acoustic liners on a 1.5 pressure ratio turbofan rotor. In order to improve the ability to measure small performance changes, fan performance calculations were updated to include real gas effects including the effect of humidity. For all fan cases tested, the measured difference in fan isentropic efficiency was found to be less than the measurement repeatability for a torque-based efficiency calculation (approx. = 0.2%), however, an unintended tip clearance difference between configurations makes it difficult to determine if circumferentially grooved fan cases degraded fan performance. Fan exit turbulence measurements showed a 1.5% reduction in total turbulence intensity between hardwall and circumferentially grooved fan cases in the tip vortex region, which is attributed to a disruption in the formation of the tip leakage vortex. This decrease in fan exit turbulence could potentially lead to a 1-2dB reduction in broadband rotor-stator interaction noise. Reduced aerodynamic performance losses associated with over-the-rotor liners could enable further fan noise reduction.

Beschreibung: Nearly all proglacial water discharge from the present-day Greenland Ice Sheet is routed englacially via moulins. Identification of these moulins in high-resolution imagery is a frequent topic of study, but the processes controlling how and where moulins form, including on past ice sheets for which remote-sensing data are not available, remain poorly understood. Because moulins may reasonably compose approximately 10-15% of the englacial-subglacial hydrologic system, the evolution and shape of moulins can alter the timing of meltwater inputs to the bed. This evolution can impact both the form of the subglacial hydrologic system and the structure of associated geomorphological structures. Here, we develop a physical model of moulin formation and evolution to constrain the role of englacial processes in controlling the form and structure of the subglacial hydrologic system. Ice deformation within and around a moulin is both viscous and elastic, with the rate of turbulent and heat dissipation from water circulation in the moulin controlling both moulin wall melting and warming of the surrounding ice. We find moulin geometry is responsive to changes in these parameters over hours to days, indicating that diurnal and multi-day variations in surface melt can substantially alter the geometry of a moulin and the pressure-discharge relationship at the bed of the ice sheet. These results should be considered carefully when determining surface water inputs for subglacial hydrologic models. In the future, a parameter space study of these results will be combined with an analytic model to create a predictive, stochastic model of moulin and crevasse locations. This future model will be applicable to constraining the potential for surface-to-bed connections in regions where the exact ice-sheet surface morphology is not known, including ice sheets under future warming atmospheric conditions, and paleo ice sheets, where moulins created modern landforms.

Beschreibung: A full-scale isolated proprotor test is currently being conducted in the USAF National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel at NASA Ames. The test article is a 3-bladed research rotor derived from the right-hand rotor of the AW609; this rotor was manufactured by Bell Helicopter under contract to NASA. In this paper, this research rotor is referred to as "699". The test, nearly completed, is an integral part of the initial checkout test of the newly developed Tiltrotor Test Rig (TTR), whose purpose is to test advanced, full-scale proprotors in the NFAC. Figure 1 shows the TTR/699 installed in the 40- by 80-Foot test section. The TTR rotor axis is horizontal and the rig rotates in yaw on the wind tunnel turntable for conversion (transition) and helicopter mode testing. To date, a substantial amount of wind tunnel test data has already been acquired. The completed operational conditions include hover, airplane mode (cruise, wind tunnel airspeed V=61 to 267 knots), and the helicopter and conversion conditions (with a comprehensive sweep of the TTR yaw angle ranging, to date, from 90-deg yaw helicopter mode to 30-deg yaw conversion mode, at varying airspeeds). This 699 proprotor performance and loads correlation study uses these newly acquired wind tunnel test data. This paper represents the third analytical study, coming after two earlier analytical studies on the TTR/699; that is, a 2018 paper on pre-test predictions of 699 performance and loads, Ref. 1, and an upcoming January 2019 paper on aeroelastic stability analysis of the TTR/699 installed in the 40- by 80-Foot Wind Tunnel, Ref. 2. Reference 8 will present an overview of the entire TTR/699 test program. For completeness, Ref. 3 addresses the development and initial testing of the TTR. Background information on the TTR effort at NASA Ames can be found at the Aeromechanics website: https://rotorcraft.arc.nasa.gov/Research/Facilities/ttr.html. To the authors' knowledge, the full-scale results presented in this paper are the first of their kind. A literature survey brought up several existing correlation studies, but these were either based on small-scale test data (for example, the studies performed by the University of Maryland) or full-scale aircraft flight test data (for example, flight tests conducted by Bell Helicopter). Separately, the 2009 NASA study involving the JVX rotor is relevant (see Ref.4). The JVX is closely similar to the 699 in size and aerodynamics, and is accordingly a good reference for performance calculations. In Ref. 1 (as mentioned above), pre-test reality checks of the current analytical model were made by comparing JVX and 699 predictions in hover and forward flight (airplane mode).

Beschreibung: Two full seven-equation turbulence models have been implemented into the FUN3D code to evaluate their ability to improve the computation of challenging flows encountered in aerospace propulsion, including mixing flows. These models are the SSG/LRR and Wilcox full second-moment Reynolds stress models. They solve equations for the six components of the Reynolds stress and a seventh equation for the mixing length. Two standard eddy viscosity models are also evaluated for comparison, the Spalart-Allmaras (SA) one-equation model and the Menter Shear Stress Transport (SST-V) two-equation turbulence model. Flow through an axisymmetric reference nozzle is examined at three flow conditions: subsonic unheated, subsonic heated, and near sonic unheated. Centerline profiles of velocity and turbulent kinetic energy and radial profiles of velocity, turbulent kinetic energy and turbulent stresses are examined. characteristics, no significant changes in the downstream flow behavior compared to the baseline case are observed. Furthermore, the total power consumed by the fans for different incoming flow conditions also remain marginally the same. It is hoped that the results, albeit obtained at very low speeds. would serve as a database for this technologically interesting flow field that has not been explored adequately before.

Beschreibung: We consider the formation of a potential drop over the Earth's polar cap during geomagnetically quiet daytime. The observed potential drop is primarily defined by the hydrogen, photoelectron, and polar rain fluxes ratios and depends strongly on the energy distribution of the photoelectron flux. Polar rain is an essential component of the model required for plasma quasineutrality. The potential distribution along the magnetic field line has two regions, with a small, gradual, potential drop of 3 to 4 volts and a potential jump. The value of the potential jump depends on the hydrogen ion to photoelectron flux ratio and is also controlled by polar rain electrons. With quasineutrality required at its upper boundary, the jump only occurs in the presence of polar rain and its location depends on the polar rain flux. Model predictions compare well with FAST (Fast Auroral SnapshoT) observations presented by Kitamura et al.(2012, https://doi.org/10.1029/2011JA017459).

Beschreibung: Heated ethane (C2H6) has been proposed as an alternative to inert gases for use as a motive fluid in the experimental simulation of rocket exhaust plumes. By adjusting stagnation temperature, the isentropic exponent of ethane can be tuned to approximate those produced by common rocket propellants including hydrogen, hypergols, alcohols, and hydrocarbons. As a result, ethane can be made to follow a nozzle expansion process which is nearly identical to realistic rocket engine flow fields. Additionally, its high auto-ignition temperature and resistance to condensation enable the testing of expansion ratios much larger than conventional inertgas testing. NASA SSC has performed quasi-one-dimensional analyses using the Chemical Equilibrium with Applications (CEA) code as a preliminary means to compare flow fields produced by non-reacting ethane to those of reacting combustion products. A LO2/LH2 rocket engine operating at a chamber pressure of 5.0 MPa and a mixture ratio of 6.1 was used as an example case to demonstrate ethanes efficacy as a simulant. Errors for key similarity parameters were compared to legacy cold-flow test methods. Additional errors induced by machining tolerances and chemical impurities were also examined. Results suggest that at a 3% geometric scale and ~500 K ethane stagnation temperature, an error of less than 2.5% throughout the flow field is realistically achievable along the dimensions of Mach number, Reynolds number, pressure ratio, and isentropic exponent. The development of an experimental test bed for validation of this configuration is currently underway.

Beschreibung: A 13.49-percent-thick, slotted, natural-laminar-flow airfoil, the S207, for a transport aircraft has been designed and analyzed theoretically. The two primary objectives of high maximum lift, insensitive to roughness, and low profile drag have been achieved. The drag-divergence Mach number is predicted to be greater than 0.70.

Beschreibung: The values of the key atmospheric turbulence parameters (structure constants) for temperature and water vapor, that is, C(exp 2)(sub T), and C(exp 2)(sub Q), are highly dependent upon the vertical height within the atmosphere thus making it necessary to specify profiles of these values along the atmospheric propagation path. The remote sensing method suggested and described in this work makes use of a rapidly integrating microwave profiling radiometer to capture profiles of temperature and humidity through the atmosphere. The integration times of currently available profiling radiometers are such that they are approaching the temporal intervals over which one can possibly make meaningful assessments of these key atmospheric parameters. These integration times, coupled with the boundary effects of the Earths surface are, however, unconventional for turbulence characterization; the classical Kolmogorov turbulence theory and related 2/3 law for structure functions prevalent in the inertial subrange are no longer appropriate. An alternative to this classical approach is derived from first principles to account for the nuances of turbulent mechanics met with using radiometer sensing, that is, the large-scale turbulence driven by the various possible boundary conditions within the buoyancy subrange. Analytical expressions connecting the measured structure functions to the corresponding structure parameters are obtained. The theory is then applied to an experimental scenario involving radiometric profile measurements of temperature and shows very good results.

Beschreibung: Since the early twentieth century, the amplitudes of tidal constituents in the Gulf of Maine and Bay of Fundy display clear secular trends that are among the largest anywhere observed for a regional body of water. The M2 amplitude at Eastport, Maine, increased at a rate of 14.1 1.2 cm per century until it temporarily dropped during 19801990, apparently in response to changes in the wider North Atlantic. Annual tidal analyses indicate M2 reached an alltime high amplitude last year (2018). Here we report new estimates of tides derived from nineteenth century waterlevel measurements found in the U.S. National Archives. Results from Eastport, Portland, and Pulpit Harbor (tied to Bar Harbor) do not follow the twentieth century trends and indicate that the Gulf of Maine tide changes commenced sometime in the late nineteenth or early twentieth centuries, coincident with a transition to modern rates of sealevel rise as observed at Boston and Portland. General agreement is that sea level rise alone is insufficient to cause the twentiethcentury tide changes. A role for ocean stratification is suggested by the longterm warming of Gulf of Maine waters; archival water temperatures at Boston, Portland, and Eastport show increases of 2 C since the 1880s. In addition, a changing seasonal dependence in M2 amplitudes is reflected in a changing seasonal dependence in water temperatures. The observations suggest that models seeking to reproduce Gulf of Maine tides must consider both sea level rise and longterm changes in stratification.

Beschreibung: NASA's ASPIRE (Advanced Supersonic Parachute Inflation Research Experiments) project was launched to investigate the supersonic deployment, inflation and aerodynamics of full-scale disk-gap-band (DGB) parachutes. Three flight tests (October 2017, March 2018 and July 2018) deployed and examined parachutes meant for the upcoming "Mars 2020" mission. Mars-relevant conditions were achieved by performing the tests at high altitudes over Earth on a sounding rocket platform, with the parachute deploying behind a slender body (roughly 1/6-th the diameter of the capsule that will use this parachute for descent at Mars). All three tests were successful and delivered valuable data and imagery on parachute deployment and performance. CFD simulations were used in designing the flight test, interpreting the flight data, and extrapolating the results obtained during the flight test to predict parachute behavior at Mars behind a blunt capsule. This presentation will provide a brief overview of the test program and flight test data, with emphasis on differences in parachute performance due to the leading body geometry.

Beschreibung: Aerodynamic assessment of icing effects on swept wings is an important component of a larger effort to improve three-dimensional icing simulation capabilities. An understanding of ice-shape geometric fidelity and Reynolds and Mach number effects on iced-wing aerodynamics is needed to guide the development and validation of ice-accretion simulation tools. To this end, wind-tunnel testing was carried out for 8.9% and 13.3% scale semispan wing models based upon the Common Research Model airplane configuration. Various levels of geometric fidelity of an artificial ice shape representing a realistic glaze-ice accretion on a swept wing were investigated. The highest fidelity artificial ice shape reproduced all of the three-dimensional features associated with the glaze ice accretion. The lowest fidelity artificial ice shapes were simple, spanwise-varying horn ice geometries intended to represent the maximum ice thickness on the wing upper surface. The results presented in this paper show that changes in Reynolds and Mach number have only a small effect on the iced-wing aerodynamics relative to the clean-wing configuration. Furthermore, the addition of grit roughness to some lower-fidelity artificial ice shapes resulted in favorable lift and pitching moment comparisons to the wing with the highest fidelity artificial ice shape. For the wing with simple horn ice shapes, the dependence of maximum lift coefficient on horn height and angle are generally consistent with the trends observed for similar experiments conducted on iced airfoils in past research. In terms of usable lift however, the horn height did have a significant effect even for lower horn angles. This could be an important finding since usable lift may be more indicative of the impending iced-swept wing stall and need for additional pitch control than maximum lift coefficient.

Beschreibung: No abstract available

Beschreibung: This paper describes properties and behavior of magnetic reconnection and flux transfer events (FTEs) on the dayside magnetopause using the global hybrid-Vlasov code Vlasiator. We investigate two simulation runs with and without a sunward (positive) B(sub x) component of the interplanetary magnetic field (IMF) when the IMF is southward. The runs are two-dimensional in real space in the noon-midnight meridional (polar) plane and three-dimensional in velocity space. Solar wind input parameters are identical in the two simulations with the exception that the IMF is purely southward in one but tilted 45 toward the Sun in the other. In the purely southward case (i.e., without B(sub x) the magnitude of the magnetosheath magnetic field component tangential to the magnetopause is larger than in the run with a sunward tilt. This is because the shock normal is perpendicular to the IMF at the equatorial plane, whereas in the other run the shock configuration is oblique and a smaller fraction of the total IMF strength is compressed at the shock crossing. Hence, the measured average and maximum reconnection rate are larger in the purely southward run. The run with tilted IMF also exhibits a north-south asymmetry in the tangential magnetic field caused by the different angle between the IMF and the bow shock normal north and south of the equator. Greater north-south asymmetries are seen in the FTE occurrence rate, size, and velocity as well; FTEs moving toward the Southern Hemisphere are larger in size and observed less frequently than FTEs in the Northern Hemisphere.

Beschreibung: Swept wings and control surfaces are common elements of modern aircraft, and it has been shown both experimentally and theoretically that laminar-to-turbulent transition of the three-dimensional boundary layer that develops over them is highly sensitive to surface roughness. Numerous studies have been conducted on the effect of discrete roughness elements or distributed roughness elements on swept flow transition, however so far limited computational effort has been dedicated to the study of transition over swept wings with randomly distributed micron-sized roughness. In the present work, we set up to reproduce the extensive experimental data base generated by Dagenhart et al for the infinite swept wing NLF(2)-0415. To this purpose, we perform scale-resolving simulations of flow transition over smooth and rough surfaces using a high-order space-time spectral-element Discontinuous-Galerkin solver. Different types of surface roughnesses are implemented by elastically deforming the original mesh. The study shows that the experimental results cannot be accounted for by a perfectly smooth wing and reveals a strong sensitivity of the transition process to the representation of the surface roughness. The crossflow patterns and transition location approach those measured for some of the surface profiles, however a correlation between the wavenumber spectrum of the surface, grid resolution and boundary layer stability is yet to be established.

Beschreibung: Paper describing the outreach activities at INGV.

Beschreibung: Published

Beschreibung: 529-535

Beschreibung: 2TM. Divulgazione Scientifica

Beschreibung: JCR Journal

Beschreibung: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in International Journal of Environmental Research and Public Health 15 (2018): 723, doi:10.3390/ijerph15040723.

Beschreibung: There has been a massive increase in recent years of the use of lead (Pb) isotopes in attempts to better understand sources and pathways of Pb in the environment and in man or experimental animals. Unfortunately, there have been many cases where the quality of the isotopic data, especially that obtained by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS), are questionable, resulting in questionable identification of potential sources, which, in turn, impacts study interpretation and conclusions. We present several cases where the isotopic data have compromised interpretation because of the use of only the major isotopes 208Pb/206Pb and 207Pb/206Pb, or their graphing in other combinations. We also present some examples comparing high precision data from thermal ionization (TIMS) or multi-collector plasma mass spectrometry (MC-ICP-MS) to illustrate the deficiency in the Q-ICP-MS data. In addition, we present cases where Pb isotopic ratios measured on Q-ICP-MS are virtually impossible for terrestrial samples. We also evaluate the Pb isotopic data for rat studies, which had concluded that Pb isotopic fractionation occurs between different organs and suggest that this notion of biological fractionation of Pb as an explanation for isotopic differences is not valid. Overall, the brief review of these case studies shows that Q-ICP-MS as commonly practiced is not a suitable technique for precise and accurate Pb isotopic analysis in the environment and health fields

Beschreibung: A family of cases each containing a small separation bubble is treated by direct numerical simulation (DNS), varying two parameters: the severity of the pressure gradients, generated by suction and blowing across the opposite boundary, and the Reynolds number. Each flow contains a well-developed entry region with essentially zero pressure gradient, and all are adjusted to have the same value for the momentum thickness, extrapolated from the entry region to the centre of the separation bubble. Combined with fully defined boundary conditions this will make comparisons with other simulations and turbulence models rigorous; we present results for a set of eight Reynolds-averaged NavierStokes turbulence models. Even though the largest Reynolds number is approximately 5.5 times higher than in a similar DNS study we presented in 1997, the models have difficulties matching the DNS skin friction very closely even in the zero pressure gradient, which complicates their assessment. In the rest of the domain, the separation location per se is not particularly difficult to predict, and the most definite disagreement between DNS and models is near reattachment. Curiously, the better models tend to cluster together in their predictions of pressure and skin friction even when they deviate from the DNS, although their eddy-viscosity levels are widely different in the outer region near the bubble (or they do not rely on an eddy viscosity). Stratfords square-root law is satisfied by the velocity profiles, both at separation and reattachment. The Reynolds-number range covers a factor of two, with the Reynolds number based on the extrapolated momentum thickness equal to approximately 1500 and 3000. This allows tentative estimates of the improvements that even higher values will bring to the model comparisons. The solutions are used to assess models through pressure, skin friction and other measures; the flow fields are also used to produce effective eddy-viscosity targets for the models, thus guiding turbulence-modelling work in each region of the flow.

Beschreibung: The origins, development, implementation, and application of AEROM, NASA's patented reduced-order modeling (ROM) software, are presented. Full computational fluid dynamic (CFD) aeroelastic solutions and ROM aeroelastic solutions, computed at several Mach numbers using the NASA FUN3D CFD code, are presented in the form of root locus plots in order to better reveal the aeroelastic root migrations with increasing dynamic pressure. The method and software have been applied successfully to several con figurations including the Lockheed-Martin N+2 supersonic configuration and the Royal Institute of Technology (KTH, Sweden) generic wind-tunnel model, among others. The software has been released to various organizations with applications that include CFD-based aeroelastic analyses and the rapid modeling of high- fidelity dynamic stability derivatives. Recent results obtained from the application of the method to the AGARD 445.6 wing will be presented that reveal several interesting insights.

Beschreibung: Infrared radiative cooling by nitric oxide (NO) and carbon dioxide (CO2) modulates the thermospheres density and thermal response to geomagnetic storms. Satellite tracking and collision avoidance planning require accurate density forecasts during these events. Over the past several years, failed density forecasts have been tied to the onset of rapid and significant cooling due to production of NO and its associated radiative cooling via emission of infrared radiation at 5.3 m. These results have been diagnosed, after the fact, through analyses of measurements of infrared cooling made by the Sounding of the Atmosphere using Broadband Emission Radiometry instrument now in orbit over 16 years on the National Aeronautics and Space Administration Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics satellite. Radiative cooling rates for NO and CO2 have been further shown to be directly correlated with composition and exospheric temperature changes during geomagnetic storms. These results strongly suggest that a network of smallsats observing the infrared radiative cooling of the thermosphere could serve as space weather sentinels. These sentinels would observe and provide radiative cooling rate data in real time to generate nowcasts of density and aerodynamic drag on space vehicles. Currently, radiative cooling is not directly considered in operational space weather forecast models. In addition, recent research has shown that different geomagnetic storm types generate substantially different infrared radiative response, and hence, substantially different thermospheric density response. The ability to identify these storms, and to measure and predict the Earths response to them, should enable substantial improvement in thermospheric density forecasts.

Beschreibung: The paper is focusing on the representativeness of single lidar stations for zonally averaged ozone profile variations over the middle and upper stratosphere. From the lower to the upper stratosphere, ozone profiles from single or grouped lidar stations correlate well with zonal means calculated from Solar Backscatter Ultraviolet Radiometer (SBUV) satellite overpasses. The best representativeness with significant correlation coefficients is found within 15 degrees of latitude circles north or south of any lidar station. The paper includes also a multiple linear regression analysis on the relative importance of proxy time series for explaining variations in the vertical ozone profiles. Studied proxies represent variability due to influences outside of the earth system (solar cycle), as well as within the earth system i.e. dynamic processes (the Quasi Biennial Oscillation (QBO), the Arctic Oscillation (AO), the Antarctic Oscillation (AAO), the El Nio Southern Oscillation (ENSO)), those due to volcanic aerosol (Aerosol Optical Depth (AOD)), and to the tropopause height changes (including global warming) and those due to manmade contributions to chemistry (Equivalent Effective Stratospheric Chlorine (EESC)). Ozone trends are estimated, with and without removal of proxies, from the total available 1980 to 2015 SBUV record. Except for the chemistry related proxy (EESC) and its orthogonal function, the removal of the other proxies does not alter the significance of the estimated long-term trends. At heights above 15 hPa an inflection point between 1997 and 1999 marks the end of significant negative ozone trends, followed by a recent period between 1998-2015 with positive ozone trends. At heights between 15 hPa and 40 hPa the pre-1998 negative ozone trends tend to become less significant as we move towards 2015, below which the lower stratosphere ozone decline continues in agreement with findings of recent literature.

Beschreibung: Bio-inspired artificial hair sensors have the potential to detect aerodynamic flow features such as stagnation point, flow separation, and flow reattachment that could be beneficial for ight control and performance enhancement of aircraft. In this work, elastic microfence structures were tested on a at-plate setup. The microfences were fabricated from a two-part silicone molded against a template patterned by laser ablation. The response of the microfences to different freestream velocities and to flow reversal at the sensor were recorded via an optical microscope.

Beschreibung: We forecast the global effects of space weather on the geoelectric and geomagnetic fields using a novel combination of methods. We use a realistic three-dimensional (3-D) model of Earth's electrical conductivity and a realistic representation of magnetospheric and ionospheric current systems. Our scheme involves the following steps: (1) We run a global magnetohydrodynamic model of the magnetosphere coupled to an electrostatic model of the ionosphere. (2) We calculate a global time series of the ground magnetic field resulting from the ionospheric, field-aligned, and magnetospheric currents of the global magnetohydrodynamic model. (3) We approximate this external field by an equivalent source current flowing in a thin shell above Earth. (4) We calculate a global time series of geoelectric and geomagnetic fields from the equivalent current and a 3-D conductivity model of Earth that also takes into account the coast effect due to large horizontal conductivity gradient. We verify our implementation by comparing the results against known analytic and numeric solutions, and then apply our scheme to the geomagnetic storm of 14 and 15 December 2006. In particular, we show that accounting for 3-D structure of Earth's conductivity results in significantly enhanced geoelectric field at large lateral gradients of conductivity, especially in coastal regions, both at middle and high latitudes. In the studied geomagnetic storm the largest values of 3-D geoelectric field are detected at high latitudes reaching 2.5 volts per kilometer and the 3-D effect extends inland by a few hundred kilometers.

Beschreibung: The 2016-17 Arctic sea ice growth season (October-March) exhibited the lowest end-of-season sea ice volume and extent of any year since 1979. An analysis of MERRA2 atmospheric reanalysis data and CERES radiative flux data reveals that a record warm and moist Arctic atmosphere supported the reduced sea ice growth through two pathways. First, numerous regional episodes of increased atmospheric temperature and moisture, transported from lower latitudes, increased the cumulative energy input from downwelling longwave surface fluxes. Second, in those same episodes, the efficiency that the atmosphere cooled radiatively to space was reduced, increasing the amount of energy retained in the Arctic atmosphere and reradiated back toward the surface. Overall, the Arctic radiative cooling efficiency shows a decreasing trend since 2000. The results presented highlight the increasing importance of atmospheric forcing on sea ice variability demonstrating that episodic Arctic atmospheric rivers, regions of elevated poleward water vapor transport, and the subsequent surface energy budget response is a critical mechanism actively contributing to the evolution of Arctic sea ice.

Beschreibung: Project Link! is a NASA-led effort to study the feasibility of multi-aircraft aerial docking systems. In these systems, a group of vehicles physically link to each other during flight to form a larger ensemble vehicle with increased aerodynamic performance and mission utility. This paper presents a dynamic model and control architecture for a system of fixed-wing vehicles with this capability. The dynamic model consists of the 6 degree-of-freedom fixed-wing aircraft equations of motion, a spring-damper-magnet system to represent the linkage force between constituent vehicles, and the NASA-Burnham-Hallock wingtip vortex model to represent the close-proximity aerodynamic interactions between constituents before the linking occurs. The control architecture consists of a guidance algorithm to autonomously drive the constituents towards their linking partners and an inner-loop angular rate controller. A simulation was constructed from the model, and the flight dynamic modes of the linked system were compared to the individual vehicles. Simulation results for both before and after linking are presented.

Beschreibung: Structural optimization with a flutter constraint for a vehicle designed to fly in the transonic regime is a particularly difficult task. In this speed range, the flutter boundary is very sensitive to aerodynamic nonlinearities, typically requiring high-fidelity Navier-Stokes simulations. However, the repeated application of unsteady computational fluid dynamics to guide an aeroelastic optimization process is very computationally expensive. This expense has motivated the development of methods that incorporate aspects of the aerodynamic nonlinearity, classical tools of flutter analysis, and more recent methods of optimization. While it is possible to use doublet lattice method aerodynamics, this paper focuses on the use of an unsteady high-fidelity aerodynamic reduced order model combined with successive transformations that allows for an economical way of utilizing high-fidelity aerodynamics in the optimization process. This approach is applied to the common research model wing structural design. The high-fidelity aerodynamics produces a heavier wing than that optimized with doublet lattice aerodynamics. It is found that the optimized lower wing skin thickness distribution using high-fidelity aerodynamics differs significantly from that using doublet lattice aerodynamics.

Beschreibung: Recently launched cloud observing satellites provide information about the vertical structure of deep convection and its microphysical characteristics. In this study, CloudSat reflectivity data is stratified by cloud type, and the contoured frequency by altitude diagrams reveal a doublearc structure in deep convective cores (DCCs) above 8 km. This suggests two distinct hydrometeor modes (snow versus hail/graupel) controlling variability in reflectivity profiles. The daynight contrast in the double arcs is about four times larger than the wetdry season contrast. Using QuickBeam, the vertical reflectivity structure of DCCs is analyzed in two versions of the Superparameterized Community Atmospheric Model (SP-CAM) with single-moment (no graupel) and double-moment (with graupel) microphysics. Doublemoment microphysics shows better agreement with observed reflectivity profiles; however, neither model variant captures the double-arc structure. Ultimately, the results show that simulating realistic DCC vertical structure and its variability requires accurate representation of ice microphysics, in particular the hail/graupel modes, though this alone is insufficient.

Beschreibung: Attribution of Antarctic ozone recovery to the Montreal protocol requires evidence that (1)Antarctic chlorine levels are declining and (2) there is a reduction in ozone depletion in response to achlorine decline. We use Aura Microwave Limb Sounder measurements of O3, HCl, and N2O to demonstratethat inorganic chlorine (Cly) from 2013 to 2016 was 223 93 parts per trillion lower in the Antarctic lowerstratosphere than from 2004 to 2007 and that column ozone depletion declined in response. The mean Clydecline rate, ~0.8%/yr, agrees with the expected rate based on chlorofluorocarbon lifetimes. N2Omeasurements are crucial for identifying changes in stratospheric Cly loading independent of dynamicalvariability. From 2005 to 2016, the ozone depletion and Cly time series show matching periods of decline,stability, and increase. The observed sensitivity of O3 depletion to changing Cly agrees with the sensitivitysimulated by the Global Modeling Initiative chemistry transport model integrated

Beschreibung: The existing database of transition measurements in hypersonic ground facilities has established that the onset of boundary layer transition over a circular cone at zero angle of attack shifts downstream as the nosetip bluntness is increased with respect to a sharp cone. However, this trend is reversed at suciently large values of the nosetip Reynolds number, so that the transition onset location eventually moves upstream with a further increase in nosetip bluntness. This transition reversal phenomenon, which cannot be ex- plained on the basis of linear stability theory, was the focus of a collaborative investigation under the NATO STO group AVT-240 on Hypersonic Boundary-Layer Transition Predic- tion. The current paper provides an overview of that e ort, which included wind tunnel measurements in three di erent facilities and theoretical analysis related to modal and nonmodal ampli cation of boundary layer disturbances. Because neither rst and second- mode waves nor entropy-layer instabilities are found to be substantially ampli ed to ini- tiate transition at large bluntness values, transient (i.e., nonmodal) disturbance growth has been investigated as the potential basis for a physics-based model for the transition reversal phenomenon. Results of the transient growth analysis indicate that disturbances that are initiated within the nosetip or in the vicinity of the juncture between the nosetip and the frustum can undergo relatively signi cant nonmodal ampli cation and that the maximum energy gain increases nonlinearly with the nose radius of the cone. This nding does not provide a de nitive link between transient growth and the onset of transition, but it is qualitatively consistent with the experimental observations that frustum transition during the reversal regime was highly sensitive to wall roughness, and furthermore, was dominated by disturbances that originated near the nosetip.

Beschreibung: Both magnetic and seismic techniques can provide information about the Moho (Mohorovicic discontinuity). We develop a new technique that provides a better estimate of the magnetic thickness of the crust, as compared with previous approaches. It uses prior knowledge from seismology (Crust 1.0), a new high-degree model from CHAMP (CHAllenging Mini-satellite Payload) and Swarm (LCS-1 - a model of Earth's lithospheric field) and a newly developed technique. The technique is appropriate for regions where induced magnetization dominates over remanent magnetization. We compare the predictions from LCS-1 with those from Crust 1.0, with some simple assumptions, and find that the correlations increase until about spherical harmonic degree 30, and then decrease globally. Spatially, the correlations between the seismic and magnetic techniques are strongest over North America and Australia, and weakest over South America and northern Africa. Strong correlations also exist between the two approaches over the Antarctic, northern Europe, and Greenland. While we might expect the seismic and magnetic approaches to correlate over well-characterized regions (i.e. North America), and show weaker correlations over poorly-characterized regions (i.e. South America and north Africa), the strong correlation in the Antarctic and Greenland is puzzling, because both of these regions are poorly-characterized. We discuss some possible explanations, and implications, of this attempt to correlate seismic and magnetic approaches to characterizing the lithosphere.

Beschreibung: Laser Ablation ICP-MS (LA-ICP-MS) has been widely accepted as a microanalytical technique for in-situ trace (ppb) elemental analysis on the micron scale in a variety of geologic materials. LA-ICP-MS (single or multi-collector) provides both elemental and isotopic measurements critical for a wide range of geological research by generating a fine grained aerosol (nm scale) during the laser ablation event and delivering that aerosol to the ICP ion source of the mass spectrometer via an inert carrier gas. LA-ICP-MS, however, suffers from limitations in analyzing high ionization potential elements as well as elements subject to atmospheric and argon based interferences. LA-ICP-MS also has limitations in analyzing major elements due to detector saturation. An alternative laser ablation technique, Laser Induced Breakdown Spectroscopy (LIBS), employs an optical spectrometer integrated into the laser ablation system that analyzes the laser induced plasma at the sample surface across the entire optical spectrum for emission lines of every element in the periodic table. Elements that are difficult or impossible to measure with LA-ICP-MS are now possible to analyze with LIBS down to low ppm levels with CCD and/or ICCD detection. We introduce a new laser based technique, Tandem LA-LIBS, that combines LA for ICP-MS and LIBS into one integrated laser ablation system. This system has the effect of expanding the elemental coverage and the dynamic range of the laser ablation experiment as measurements from ppb to % level matrix elements can now be analyzed in a single ablation experiment. We present both femtosecond and nanosecond Tandem LA-LIBS quantitative and qualitative data on wide range of geological materials for those elements that are difficult or impossible by traditional LA-ICP-MS techniques such as F, H, O, N, C, S, halogens, etc. We also demonstrate that the simultaneous measurement of trace, minor and major elements are now possible in a single laser ablation experiment with Tandem LA-LIBS technology.

Beschreibung: NASAs ASPIRE (Advanced Supersonic Parachute Inflation Research Experiments) project is investigating the supersonic deployment, inflation and aerodynamics of full-scale disk-gap-band (DGB) parachutes. The first two flight tests were carried out in October 2017 and March 2018, while a third test is planned for the fall of 2018. In these tests, Mars-relevant conditions are achieved by deploying the parachutes at high altitudes over Earth using a sounding rocket test platform. As a result, the parachute is deployed behind a slender body (roughly 1/6-th the diameter of the capsule that will use this parachute for descent at Mars). Because there is limited flight and experimental data for supersonic DGBs behind slender bodies, the development of the parachute aerodynamic models was informed by CFD simulations of both the leading body wake and the parachute canopy. This presentation will describe the development of the pre-flight parachute aerodynamic models and compare pre-flight predictions with the reconstructed performance of the parachute during the flight tests. Specific attention will be paid to the differences in parachute performance behind blunt and slender bodies.

Beschreibung: Numerical simulations have been performed for a simplified high-lift configuration that is representative of a modern transport airplane. This configuration includes a leading-edge slat, fuselage, wing, nacelle-pylon and a simple hinged flap. The suction surface of the flap is embedded with multiple rows of fluidic actuators to reduce the extent of reversed flow regions and improve the aerodynamic performance of the configuration with flap in a deployed state. In the current paper, a Lattice Boltzmann Method based high-fidelity computational fluid dynamics (CFD) code, known as PowerFLOW is used to simulate the entire flow field associated with this configuration, including the flow inside the actuators. A fully compressible version of the PowerFLOW code that has been validated for high speed flows is used for the present simulations to accurately represent the transonic flow regimes that are encountered in the flow field generated by the actuators operating at higher mass flow (momentum) rates required to mitigate reverse flow regions on the suction surfaces of the main wing and the flap. The numerical solutions predict the expected trends in aerodynamic forces as the actuation levels are increased. More efficient active flow control (AFC) systems and actuator arrangement for lift augmentation are emerging based on the parametric studies conducted here prior to wind tunnel tests. These numerical solutions will be compared with experimental data, once such data becomes available.

Beschreibung: Practical aspects of the frequency-domain approach for aircraft system identification are explained and demonstrated. Topics related to experiment design, flight data analysis, and dynamic modeling are included. For demonstration purposes, simulated time series data and simulated flight data from an F-16 nonlinear simulation with realistic noise are used. This approach enables detailed evaluations of the techniques and results, because the true characteristics of the data and aircraft dynamics are known for the simulated data. Analytical techniques and practical considerations are examined for the finite Fourier transform, nonparametric frequency response estimation, parametric modeling in the frequency domain, experiment design for frequency-domain modeling, data analysis and modeling in the frequency domain, and real-time calculations. Flight data from a subscale jet transport aircraft are used to demonstrate some of the techniques and technical issues.

Beschreibung: The Tiltrotor Test Rig (TTR) is being developed at the NASA Ames Research Center for testing full-scaleproprotors in the National Full-scale Aerodynamics Complex (NFAC) wind tunnel. The TTR is currentlyundergoing checkout testing to ensure its proper functionality. Part of the checkout process is a groundvibration test, or shake test, to characterize the modal characteristics of the test rig once it is installed in the wind tunnel. This paper presents a summary of the shake test procedure and an overview of the test results. The results include frequency response functions for a number of different test configurations as well as visualizations of the major mode shapes. Excitation methods included random and swept sine shaking as well as hammer impacts. At the conclusion of this paper, some recommendations are given for future shake tests.

Beschreibung: An experimental campaign was conducted to measure and to characterize the freestream disturbance levels in the NASA Langley Research Center 20-Inch Mach 6 Wind Tunnel. A pitot rake was instrumented with fast pressure transducers, hot wires, and an atomic layer thermopile to quantify the fluctuation levels of pressure, mass flux, and heat flux, respectively. In conjunction with these probe-based measurements, focused laser differential interferometry was used to optically measure density fluctuations. Measurements were made at five nominal different unit Reynolds numbers ranging from (3.28 to 26.5) times 10 (sup 6) per meter. The rake was positioned at two different stream-wise locations and several different roll angles to measure flow uniformity within the test section. In general, noise levels were spatially consistent within the tested region. Pitot pressure fluctuation levels ranged from 0.84 percent at the highest Reynolds number tested to 1.89 percent at the lowest Reynolds number tested. Freestream mass-flux fluctuations remained relatively constant between 1.8-2.5 percent of the freestream. The pressure transducers were also used to determine the dominant disturbance speed and angle of propagation. The disturbances were estimated to travel at approximately 54-81 percent of the freestream speed at an angle of approximately 21-44 degrees from the freestream direction, but these measurements had a significant amount of uncertainty. A comparison to previous measurements of pressure made in 2012 and of mass flux made in 1994 show almost no change in the RMS (Root Mean Square) fluctuation of these flow quantities.

Beschreibung: Many crucial geophysical and atmospheric science investigations at Venus require operations on the surface for an entire solar day. Until recently this was not achievable, but new developments in high temperature electronics have now made months long operations on the Venus surface possible even with smallsat class missions. Here we describe a study of a long-lived Venus lander called SAEVe, for Seismic and Atmospheric Exploration of Venus: this was one of the concepts selected in 2017 under NASA's Planetary Science Deep Space SmallSat Studies (PSDS3) call.

Beschreibung: Heat transfer measurements were obtained on the endwall and a 2-D section of a variable speed power turbine (VSPT) rotor blade. Infrared thermography was used to help determine the transition of flow from laminar to turbulent as well asdetermine regions of flow separation. Steady state data was obtained for six incidence angles ranging from +50 degree to-17 degree, and at five flow conditions for each angle.

Beschreibung: The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) has been the home of processing, archiving, and distribution services for data from the Atmospheric Infrared Sounder (AIRS) mission since its launch in 2002. AIRS provides data enabling global observations of the atmospheric state. The GES DISC provides service to both AIRS standard products and Near Real-time (NRT) products. The AIRS NRT product is one important element in the Land, Atmosphere Near real-time Capability for EOS (LANCE). The LANCE processing of the AIRS NRT product and the generation of the imagery are performed at the GES DISC. The AIRS NRT imagery are generated by mosaicking and mapping the available AIRS 6-minute retrieval granules to a global cylindrical projection. The images are constantly refreshed when new granules are produced. The AIRS NRT Viewer and LANCE Worldview provide visualization services to online users for AIRS NRT imagery. The imagery include atmospheric temperature, humidity, precipitation, Dust Score, CO, and SO2. The AIRS Applications Development Team at NASA JPL developed a new orbit-based algorithm and software to improve the AIRS NRT imagery. The GES DISC is collaborating with the AIRS Applications Development Team for the implementation of the new algorithm and software. The improvements include image quality, new color palettes, and variable changes. In this presentation, we will detail the improvements and demonstrate visualization of the new imagery.

Beschreibung: The purpose of the Preliminary Research in AerodyNamicDesign to Lower Drag (PRANDTL-D) project is to show that birds fly using a "bell" shaped spanload rather than using an elliptical shaped spanload and to demonstrate the extensive benefits of this alternative spanload. This validation is done by flying a research glider with a twenty five foot wingspan that collects a range of parameters in flight. To ensure the data collection computers and suite of sensors work together and mesh well with the aircraft, systems engineering principles are applied. Needs for new one-off parts require a systems engineering approach as all the criteria of the plane, such as aerodynamics, structures, and avionics, must be taken into account when making decisions. The result of this approach were effective solutions that had a minimal negative impact on other systems that were not related to the original problem.

Beschreibung: Determining the magnetic field structure, electric currents, and plasma distributions within flux transfer event (FTE)-type flux ropes is critical to the understanding of their origin, evolution, and dynamics. Here the Magnetospheric Multiscale mission's high-resolution magnetic field and plasma measurements are used to identify FTEs in the vicinity of the subsolar magnetopause. The constant-alpha flux rope model is used to identify quasi-force free flux ropes and to infer the size, the core magnetic field strength, the magnetic flux content, and the spacecraft trajectories through these structures. Our statistical analysis determines a mean diameter of 1,700 400 km (~30 9 d(sub i)) and an average magnetic flux content of 100 30 kWb for the quasi-force free FTEs at the Earth's subsolar magnetopause which are smaller than values reported by Cluster at high latitudes. These observed nonlinear size and magnetic flux content distributions of FTEs appear consistent with the plasmoid instability theory, which relies on the merging of neighboring, small-scale FTEs to generate larger structures. The ratio of the perpendicular to parallel components of current density, R(sub J), indicates that our FTEs are magnetically force-free, defined as R(sub J) 〈 1, in their core regions (〈0.6 R(sub flux rope)). Plasma density is shown to be larger in smaller, newly formed FTEs and dropping with increasing FTE size. It is also shown that parallel ion velocity dominates inside FTEs with largest plasma density. Field-aligned flow facilitates the evacuation of plasma inside newly formed FTEs, while their core magnetic field strengthens with increasing FTE size.

Beschreibung: The accurate prediction of wall-roughness effects in turbomachinery is becoming critical as turbine designers address airfoil surface quality and degradation concerns arising from the shift to advanced ceramic matrix composite (CMC) or additively-manufactured airfoils operating in higher temperature environments. In this paper, a recently developed computational capability for accurate and efficient scale-resolving simulations of turbomachinery is extended to analyze the boundary- layer separation and transition characteristics in a rough-wall low-pressure turbine (LPT) cascade. The computational capability is based on an entropy-stable discontinuous-Galerkin spectral-element approach that extends to arbitrarily high orders of spatial and temporal accuracy, and is implemented in an efficient manner for a modern high performance computer architecture. Results from the scale-resolving simulations of both smooth and rough airfoil cascades are presented and compared to previous experiments and numerical simulations. The results show that the suction surface boundary layer undergoes laminar separation, transition, and turbulent reattachment for the smooth airfoil cascade, while in the presence of roughness the separation and transition behavior of the suction surface boundary layer is substantially modified. The differences between the smooth and rough airfoil cascades are then highlighted by a detailed analysis of their respective turbulent flow fields.

Beschreibung: Space-based, operational instruments are in unique positions to monitor volcanic activity globally, especially in remote locations or where suborbital observing conditions are hazardous. The Multi-angle Imaging SpectroRadiometer (MISR) provides hyper-stereo imagery, from which the altitude and microphysical properties of suspended atmospheric aerosols can be derived. These capabilities are applied to plumes emitted at Karymsky volcano from 2000 to 2017. Observed plumes from Karymsky were emitted predominantly to an altitude of 2-4 km, with occasional events exceeding 6 km. MISR plume observations were most common when volcanic surface manifestations, such as lava flows, were identified by satellite-based thermal anomaly detection. The analyzed plumes predominantly contained large (1.28 micron effective radius), strongly absorbing particles indicative of ash-rich eruptions. Differences between the retrievals for Karymsky volcano's ash-rich plumes and the sulfur-rich plumes emitted during the 2014-2015 eruption of Holuhraun (Iceland) highlight the ability of MISR to distinguish particle types from such events. Observed plumes ranged from 30 to 220 km in length, and were imaged at a spatial resolution of 1.1 km. Retrieved particle properties display evidence of downwind particle fallout, particle aggregation and chemical evolution. In addition, changes in plume properties retrieved from the remote-sensing observations over time are interpreted in terms of shifts in eruption dynamics within the volcano itself, corroborated to the extent possible with suborbital data. Plumes emitted at Karymsky prior to 2010 display mixed emissions of ash and sulfate particles. After 2010, all plumes contain consistent particle components, indicative of entering an ash-dominated regime. Post-2010 event timing, relative to eruption phase, was found to influence the optical properties of observed plume particles, with light-absorption varying in a consistent sequence as each respective eruption phase progressed.

Beschreibung: The new check standard model of the NASA Ames 11-ft Transonic Wind Tunnel was chosen for a future validation of the facility's wall interference correction system. The chosen validation approach takes advantage of the fact that test conditions experienced by a large model in the slotted part of the tunnel's test section will change significantly if a subset of the slots is temporarily sealed. Therefore, the model's aerodynamic coefficients have to be recorded, corrected, and compared for two different test section configurations in order to perform the validation. Test section configurations with highly accurate Mach number and dynamic pressure calibrations were selected for the validation. First, the model is tested with all test section slots in open configuration while keeping the model's center of rotation on the tunnel centerline. In the next step, slots on the test section floor are sealed and the model is moved to a new center of rotation that is 33 inches below the tunnel centerline. Then, the original angle of attack sweeps are repeated. Afterwards, wall interference corrections are applied to both test data sets and response surface models of the resulting aerodynamic coefficients in interference-free flow are generated. Finally, the response surface models are used to predict the aerodynamic coefficients for a family of angles of attack while keeping dynamic pressure, Mach number, and Reynolds number constant. The validation is considered successful if the corrected aerodynamic coefficients obtained from the related response surface model pair show good agreement. Residual differences between the corrected coefficient sets will be analyzed as well because they are an indicator of the overall accuracy of the facility's wall interference correction process.

Beschreibung: Moulins permit access of surface meltwater to the glacier bed, causing basal lubrication and ice speedup in the ablation zone of western Greenland during summer. Despite the substantial impact of moulins on ice dynamics, the conditions under which they form are poorly understood. We assimilate a time-series of ice surface velocity from a network of eleven Global Positioning System receivers into an ice sheet model to estimate ice sheet stresses during winter, spring, and summer in an approx. 30 x 10 km region. Surface-parallel von Mises stress increases slightly during spring speedup and early summer, sufficient to allow formation of 16% of moulins mapped in the study area. In contrast, 63% of moulins experience stresses over the tensile strength of ice during a short (hours) supraglacial lake drainage event. Lake drainages appear to control moulin density, which is itself a control on subglacial drainage efficiency and summer ice velocities.

Beschreibung: The present contribution reviews recent experimental results of roughness effects on boundary layer transition on capsule geometries with spherical windward geometries. Experiments in three wind tunnel facilities are considered. The ACE Tunnel of Texas AM University, USA, provided Mach 6 experiments with distributed roughness at relatively low Reynolds numbers, 2.5 10(exp 5) 〈 Re(sub d) 〈 5 10(exp 5), with d denoting the capsule diameter. The observed boundary layer transition compared well with correlations based on transient growth theory, even though the roughness heights were in the order of boundary layer thickness. Larger Reynolds numbers, 1 10(exp 6) 〈 Re(sub d) 〈 310(exp 6), could be assessed in the hypersonic Ludwieg tube, HLB, of TU Braunschweig, Germany. Transition is observed at rather low, subcritical roughness values in the order of 20 m for a roughness patch placed about the geometric center of the capsule model. These experiments varied fluctuation levels of the freestream. The authors assume that the observed transitions that occur downstream of the subcritical roughness patch are due to freestream disturbances in the tunnel, which interact with small roughness heights. Additional experiments in the HLB facility with patches of larger roughness height support the relevance of transient growth theory for low-to-medium roughness heights, relative to boundary layer thickness. The effects of Reynolds numbers and total flow enthalpy on transition with isolated roughness were investigated in the HIEST facility of JAXA, Japan. Here, a model insert with roughness elements of varying height for tripping transition to turbulence was employed. The results are compared to known trip effectiveness correlations for isolated roughness. Overall, the transient growth correlation seems to represent roughness-induced transition behavior on the ACE and HLB entry capsule shapes with roughness over the entire capsule surface. These experiment are however for perfect gases. Comparable experiments on roughness induced transition in a high-enthalpy facility are still needed to confirm the validity of transient-growth correlation for vehicle design.

Beschreibung: No abstract available

Beschreibung: No abstract available

Beschreibung: As part of the geolocation accuracy assessment of lightning flashes detected by the Geostationary Lightning Mapper (GLM) on the GOES-16 and GOES-17 satellites (Geostationary Operational Environmental Satellite), two satellite laser ranging stations employed laser beacon systems to generate transient light pulses that simulate natural lightning around 777.4 nm to validate the pre-launch spec of 5 km. The pulse width, repetition rate, wavelength, and power of the laser-pulses were configured to produce sufficient instrument response to be detected as synthetic lightning events by the GLM instrument. During the testing period from April 2017 to January 2018, the laser systems illuminated the GOES-16 satellite to observe diurnal variation of the GLM system response, with particular emphasis on geolocation accuracy. The final GOES-16 laser beacon tests, which used the latest updates of the geolocation algorithms implemented by the GOES-R Ground Segment, showed the offsets between the GLM geolocated location and the known laser locations were within 5 km.

Beschreibung: Hypersonic boundary-layer flows over a circular cone at moderate angle of incidence can support strong crossflow instability in between the windward and leeward rays on the plane of symmetry. Due to the more efficient excitation of stationary crossflow vortices by surface roughness, a possible path to transition in such flows corresponds to rapid amplification of the high-frequency secondary instabilities of finite amplitude stationary crossflow vortices. In the present paper, the previous analyses of crossflow instability over a 7- degree half-angle, yawed circular cone in a Mach 6 free stream have been extended to the nonlinear evolution of azimuthally localized crossflow vortex packets and the amplification characteristics and nonlinear breakdown of high-frequency secondary instabilities associated with those packets. A comparison between plane marching PSE and direct Navier-Stokes simulations (DNS) reveals favorable agreement in regard to mode shapes, most amplified disturbance frequencies, and N-factor evolution. In contrast, the quasi-parallel predictions are found to result in severe underprediction of the N-factors. The direct numerical simulations also indicate that the breakdown of secondary instabilities in a 3D hypersonic boundary layer shares certain common features with the previous computations of crossflow transition over subsonic swept wings.

Beschreibung: Observed delays in the ground response to solar wind directional discontinuities have been explained as the result of larger than expected magnetosheath propagation times. Recently, Samsonov et al. (2017, https://doi.org/10.1002/2017GL075020) showed that the typical time for a southward interplanetary magnetic field (IMF) turning to propagate across the magnetosheath is 14 min. Here by using a combination of magnetohydrodynamic simulations, spacecraft observations, and analytic calculations, we study the dependence of the propagation time on solar wind parameters and near-magnetopause cutoff speed. Increases in the solar wind speed result in greater magnetosheath plasma flow velocities, decreases in the magnetosheath thickness and, as a result, decreases in the propagation time. Increases in the IMF strength result in increases in the magnetosheath thickness and increases in the propagation time. Both magnetohydrodynamic simulations and observations suggest that propagation times are slightly smaller for northward IMF turnings. Magnetosheath flow deceleration must be taken into account when predicting the arrival times of solar wind structures at the dayside magnetopause.

Beschreibung: The eruption of Mt. Tambora in 1815 was the largest volcanic eruption of the past 500 years. The eruption had significant climatic impacts, leading to the 1816 "year without a summer", and remains a valuable event from which to understand the climatic effects of large stratospheric volcanic sulfur dioxide injections. The eruption also resulted in one of the strongest and most easily identifiable volcanic sulfate signals in polar ice cores, which are widely used to reconstruct the timing and atmospheric sulfate loading of past eruptions. As part of the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP), five state-of-the-art global aerosol models simulated this eruption. We analyze both simulated background (no Tambora) and volcanic (with Tambora) sulfate deposition to polar regions and compare to ice core records. The models simulate overall similar patterns of background sulfate deposition, although there are differences in regional details and magnitude. However, the volcanic sulfate deposition varies considerably between the models with differences in timing, spatial pattern and magnitude. Mean simulated deposited sulfate on Antarctica ranges from 19 to 264 kgkm-2 and on Greenland from 31 to 194 kgkm-2, as compared to the mean ice-core derived estimates of roughly 50 kgkm-2 for both Greenland and Antarctica. The ratio of the hemispheric atmospheric sulfate aerosol burden after the eruption to the average ice sheet deposited sulfate varies between models by up to a factor of 15. Sources of this inter-model variability include differences in both the formation and the transport of sulfate aerosol. Our results suggest that deriving relationships between sulfate deposited on ice sheets and atmospheric sulfate burdens from model simulations may be associated with greater uncertainties than previously thought.

Beschreibung: Aurorasaurus is a citizen science project that offers a new, global data source consisting of ground-based reports of the aurora. For this case study, aurora data collected during the 17-18 March 2015 geomagnetic storm are examined to identify their conjunctions with Defense Meteorological Satellite Program (DMSP) satellite passes over the high latitude auroral regions. This unique set of aurora data can provide ground-truth validation of existing auroral precipitation models. Particularly, the solar wind driven, Oval Variation, Assessment, Tracking, Intensity, and Online Nowcasting (OVATION) Prime 2013 (OP-13) model and a Kp-dependent model of Zhang-Paxton (Z-P) are utilized for our boundary validation efforts. These two similar models are compared for the first time. Global equatorward auroral boundaries are derived from the OP 13 model and the DMSP Special Sensor Ultraviolet Spectrographic Imager (SSUSI) far ultraviolet (FUV) data using the Z-P model at a fixed flux level of 0.2 erg cm(exp -2)s(exp -1). These boundaries are then compared with citizen science reports as well as with each other. Even though there are some large differences between the global boundaries for a few cases, the average difference is about 1.5 deg in geomagnetic latitude, with OP-13 being equatorward of Z-P model. When these boundaries are compared with each other as a function of local time, no clear overall trend as a function of local time was observed. It is also found that the ground based reports are more consistent with the predictions of the OP-13 model.

Beschreibung: Heat transfer measurements were obtained on the endwall of a 2-D section of a variable speed power turbine (VSPT) rotor blade linear cascade. Infrared thermography was used to help determine the transition of flow from laminar to turbulent as well as determine regions of flow separation. Steady state data was obtained for six incidence angles ranging from +15.8 deg to -51 deg, and at five flow conditions for each angle. Nusselt number was used as a method to visualize flow transition and separation on the endwall surface and showed the effects of secondary flows on the surface. Nusselt correlation with Reynolds number from multiple flow conditions was used to plot local values of the correlation exponent and indicated the state of the local boundary layer as the flow transitioned from laminar to turbulent as well as secondary flow features.

Beschreibung: Physical and compositional measurements are made at the approx. 7 km-long (approx. 2200 years B.P.) Kings Bowl basaltic fissure system and surrounding lava field in order to further understand the interaction of fissure-fed lavas with phreatic explosive events. These assessments are intended to elucidate the cause and potential for hazards associated with phreatic phases that occur during basaltic fissure eruptions. In the present paper we focus on a general understanding of the geological history of the site. We utilize geospatial analysis of lava surfaces, lithologic and geochemical signatures of lava flows and explosively ejected blocks, and surveys via ground observation and remote sensing.

Beschreibung: A test of the Boundary Layer Ingesting-Inlet / Distortion-Tolerant Fan was completed in NASA Glenn's 8-Foot by 6-Foot supersonic wind tunnel. Inlet and fan performance were measured by surveys using a set of rotating rake arrays upstream and downstream of the fan stage. Surveys were conducted along the 100 percent speed line and a constant exit corrected flow line passing through the aerodynamic design point. These surveys represented only a small fraction of the data collected during the test. For other operating points, data was recorded as snapshots without rotating the rakes which resulted in a sparser set of recorded data. This paper will discuss analysis of these additional, lower measurement density data points to expand our coverage of the fan map. Several techniques will be used to supplement the snapshot data at test conditions where survey data also exists. The supplemented snapshot data will be compared with survey results to assess the quality of the approach. Effective methods will be used to analyze the data set for which only snapshots exist.

Beschreibung: The TS division (Entry Systems and Technology Division) includes people who 1) Help design spacecraft for different exploration missions; 2) Figure out how hot the environments around a spacecraft will get; 3) Invent new materials that can protect the spacecraft; 4) Figure out how those materials will behave on a spacecraft and how thick they need to be; 5) Plan and perform tests on those materials and spacecraft designs to prove they will fly successfully; and 6) Help get those spacecraft ready to launch. This presentation will describe a little bit about all 6 areas.

Beschreibung: Rising atmospheric carbon dioxide (CO2) concentrations, primarily due to fossil fuel emissions and land-use change, are expected to continue to drive changes in both climate and the terrestrial and ocean carbon cycles. Over the past two-to-three decades, there has been considerable effort to understand how terrestrial and oceanic systems behave (in response to rising atmospheric CO2 and changing climate conditions), quantify the dynamics of system responses to environmental change, and project how the ocean and terrestrial carbon cycle will interact with, and influence, future atmospheric CO2 concentrations and climate. In this presentation, we will summarize key findings related to projected changes to the North American carbon cycle and drivers and associated consequences of these changes, as reported in Chapter 19 of the Second State of the Carbon Cycle Report (SOCCR-2). The findings not only capture projections of emissions from fossil fuel and changes in land cover and land use, but also highlight the decline in future carbon uptake capacity of North American carbon reservoirs and soil carbon losses from the Northern high-latitudes. Such a discussion of future carbon cycle changes is new in SOCCR-2, yet timely. It underlines the progress made since the release of the First State of the Carbon Cycle Report (SOCCR-1) in 2007 in identifying the vulnerability of key carbon pools and their co-evolution with changing climatic conditions. We will also discuss key knowledge gaps and outline a set of future research priorities, including both monitoring and modeling activities, that are necessary to improve projections of future changes to the North American carbon cycle and associated adaptation and resource-management decisions.

Beschreibung: The December 1974 flow in the SW rift zone at Kilauea Volcano, Hawaii, has been established as a Mars analog due to its physical, chemical, and morphological properties, as well as its interaction with the outgassing plume from the primary Kilauea caldera. We focus on a solfatara site that consists of hydrothermally altered basalt and alteration products deposited in and around a passively degassing volcanic vent situated directly adjacent to the December 1974 flow on its northwest side. Reflectance spectra are acquired in the visible/near-infrared (VNIR) region and emission spectra in the mid-infrared (MIR) range to better understand the spectral properties of hydrothermally altered materials. The VNIR signatures are consistent with silica, Fe-oxides, and sulfates (Ca, Fe). Primarily silica-dominated spectral signatures are observed in the MIR and changes in spectral features between samples appear to be driven by grain size effects in this wavelength range. The nature of the sample coating and the thermal emission signatures exhibit variations that may be correlated with distance from the vent. Chemical analyses indicate that most surfaces are characterized by silica-rich material, Fe-oxides, and sulfates (Ca, Fe). The silica and Fe-oxide-dominated MIR/VNIR spectral signatures exhibited by the hydrothermally altered material in this study are distinct from the sulfate-dominated spectral signatures exhibited by previously studied low-temperature aqueous acid-sulfate weathered basaltic glass. This likely reflects a difference in open vs. closed system weathering, where mobile cations are removed from the altered surfaces in the fumarolic setting. This work provides a unique infrared spectral library that includes martian analog materials that were altered in an active terrestrial solfatara (hydrothermal) setting. Hydrothermal environments are of particular interest as they potentially indicate habitable conditions. Key constraints on the habitability and astrobiological potential of ancient aqueous environments are provided through detection and interpretation of secondary mineral assemblages; thus, spectral detection of fumarolic alteration assemblages observed from this study on Mars would suggest a region that could have hosted a habitable environment.

Beschreibung: During the last two plus decades, The Goddard Earth Observing System (GEOS) and Massachusetts Institute of Technology (MIT) modeling groups have developed, respectively, atmosphere-only and ocean-only global general circulation models. These two models (GEOS and MIT-GCM (General Circulation Model)) have demonstrated their data assimilation capabilities with the recent releases of the Modern Era Reanalysis for Research Applications, Version 2 (MERRA-2) atmospheric reanalysis and the Estimating the Circulation and Climate of the Ocean, Version 4 (ECCO-v4) ocean (and sea ice) state estimate. Independently, the two modeling groups have also produced global atmosphere-only and ocean-only simulations with km-scale grid spacing which proved invaluable for process studies and for the development of satellite and in-situ sampling strategies. Recently, a new effort has been made to couple these two models and to leverage their data-assimilation and high resolution capabilities (i.e., eddy-permitting ocean, cloud-permitting atmosphere). The focus in the model development is put on sub-seasonal to decadal time scales. In this talk, I discuss the new coupled model and present some first coupled simulation results. This will include a high-resolution coupled GEOS-MIT simulation, whereby we have coupled a cubed-sphere-720 (approximately 1/8 degrees) configuration of the GEOS atmosphere to a latitude-longitude-cap-1080 (approximately 1/12 degrees) configuration of the MIT ocean. We compare near-surface diagnostics of this fully coupled ocean-atmosphere set-up to equivalent atmosphere-only and ocean-only simulations. In the comparisons we focus in particular on the differences in air-sea interactions between sea surface temperature (SST) and wind for the coupled and uncoupled simulations.

Beschreibung: The Magnetospheric Multiscale mission has observed electron whistler waves at the center and at the edges of magnetic holes in the dayside magnetosheath. The magnetic holes are nonlinear mirror structures since their magnitude is anticorrelated with particle density. In this article, we examine the growth mechanisms of these whistler waves and their interaction with the host magnetic hole. In the observations, as magnetic holes develop and get deeper, an electron population gets trapped and develops a temperature anisotropy favorable for whistler waves to be generated. In addition, the decrease in magnetic field magnitude and the increase in density reduce the electron resonance energy, which promotes the electron cyclotron resonance. To investigate this process, we used expanding box particle-in-cell simulations to produce the mirror instability, which then evolve into magnetic holes. The simulation shows that whistler waves can be generated at the center and edges of magnetic holes, which reproduces the primary features of the MMS observations. The simulation shows that the electron temperature anisotropy develops in the center of the magnetic hole once the mirror instability reaches its nonlinear stage of evolution. The plasma is then unstable to whistler waves at the minimum of the magnetic field structures. In the saturation regime of mirror instability, when magnetic holes are developed, the electron temperature anisotropy appears at the edges of the holes and electron distributions become more isotropic at the magnetic field minimum. At the edges, the expansion of magnetic holes decelerates the electrons, which leads to temperature anisotropies.

Beschreibung: As an extension of Lee et al. (2013), solar cycle variation of carbon monoxide (CO) is analyzed with MLS observation, which covers more than thirteen years (2004-2017) including maximum of solar cycle 24. Being produced primarily by the carbon dioxide (CO2) photolysis in the lower thermosphere, the variations of the mesospheric CO concentration are largely driven by the solar cycle modulated ultraviolet (UV) variation. This solar signal extends down to the lower altitudes by the dynamical descent in the winter polar vortex, showing a time lag that is consistent with the average descent velocity. To characterize a global distribution of the solar impact, MLS CO is correlated with the SORCE measured total solar irradiance (TSI) and UV. As high as 0.8 in most of the polar mesosphere, the linear correlation coefficients between CO and UV/TSI are more robust than those found in the previous work. The photochemical contribution explains most (68%) of the total variance of CO while the dynamical contribution accounts for 21% of the total variance at upper mesosphere. The photochemistry driven CO anomaly signal is extended in the tropics by vertical mixing. The solar cycle signal in CO is further examined with the Whole Atmosphere Community Climate Model (WACCM) 3.5 simulation by implementing two different modeled Spectral Solar Irradiances (SSIs): SRPM 2012 and NRLSSI. The model simulations underestimate the mean CO amount and solar cycle variations of CO, by a factor of 3, compared to those obtained from MLS observation. Different inputs of the solar spectrum have small impacts on CO variation.