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  • 1
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    Developments in Petrophysics (1997)
    London : The Geological Society
    Details
    Keywords: Petrophysik ; Geophysics ; Petroleum - Geology ; Petroleum engineering ; Rocks
    Description / Table of Contents: P. D. Jackson, D. G. Gunn, R. C. Flint, D. Beamish, P. I. Meldrum, M. A. Lovell, P. K. Harvey, and A. Peyton: A non-contacting resistivity imaging method for characterizing whole round core while in its liner / Geological Society, London, Special Publications, 122:1-10, doi:10.1144/GSL.SP.1997.122.01.01 --- D. J. Prosser, A. Hurst, and M. R. Wilson: One-man-operable probe permeameters / Geological Society, London, Special Publications, 122:11-18, doi:10.1144/GSL.SP.1997.122.01.02 --- S. R. McDougall, A. B. Dixit, and K. S. Sorbie: Network analogues of wettability at the pore scale / Geological Society, London, Special Publications, 122:19-35, doi:10.1144/GSL.SP.1997.122.01.03 --- S. Pugliese and N. Petford: Pore-structure visualization in microdioritic enclaves / Geological Society, London, Special Publications, 122:37-46, doi:10.1144/GSL.SP.1997.122.01.04 --- Paul B. Basan, Ben D. Lowden, Peter R. Whattler, and John J. Attard: Pore-size data in petrophysics: a perspective on the measurement of pore geometry / Geological Society, London, Special Publications, 122:47-67, doi:10.1144/GSL.SP.1997.122.01.05 --- M. S. King, A. Shakeel, and N. A. Chaudhry: Acoustic wave propagation and permeability in sandstones with systems of aligned cracks / Geological Society, London, Special Publications, 122:69-85, doi:10.1144/GSL.SP.1997.122.01.06 --- Shiyu Xu, Just Doorenbos, Sue Raikes, and Roy White: A simple but powerful model for simulating elastic wave velocities in clastic Silicate rocks / Geological Society, London, Special Publications, 122:87-105, doi:10.1144/GSL.SP.1997.122.01.07 --- T. Apuani, M. S. King, C. Butenuth, and M. H. De Freitas: Measurements of the relationship between Sonic wave velocities and tensile strength in Anisotropic rock / Geological Society, London, Special Publications, 122:107-119, doi:10.1144/GSL.SP.1997.122.01.08 --- C. McCann, J. Sothcott, and S. B. Assefa: Prediction of petrophysical properties from seismic quality factor measurements / Geological Society, London, Special Publications, 122:121-130, doi:10.1144/GSL.SP.1997.122.01.09 --- Y. F. Sun and D. Goldberg: Estimation of aspect-ratio changes with pressure from seismic velocities / Geological Society, London, Special Publications, 122:131-139, doi:10.1144/GSL.SP.1997.122.01.10 --- P. K. Harvey, M. A. Lovell, J. C. Lofts, P. A. Pezard, and J. F. Bristow: Petrophysical estimation from downhole Mineralogy logs / Geological Society, London, Special Publications, 122:141-157, doi:10.1144/GSL.SP.1997.122.01.11 --- Paul F. Worthington: Petrophysical estimation of permeability as a function of scale / Geological Society, London, Special Publications, 122:159-168, doi:10.1144/GSL.SP.1997.122.01.12 --- C. A. Gonçalves, P. K. Harvey, and M. A. Lovell: Prediction of petrophysical parameter logs using a multilayer backpropagation neural network / Geological Society, London, Special Publications, 122:169-180, doi:10.1144/GSL.SP.1997.122.01.13 --- Brian P. Moss: The partitioning of petrophysical data: a review / Geological Society, London, Special Publications, 122:181-252, doi:10.1144/GSL.SP.1997.122.01.14 --- A. Revil, P. A. Pezard, and M. Darot: Electrical conductivity, spontaneous potential and ionic diffusion in porous media / Geological Society, London, Special Publications, 122:253-275, doi:10.1144/GSL.SP.1997.122.01.15 --- Brígida Ramati P. Da Rocha and Tarek M. Habashy: Fractal Geometry, porosity and complex resistivity: from rough pore interfaces to hand specimens / Geological Society, London, Special Publications, 122:277-286, doi:10.1144/GSL.SP.1997.122.01.16 --- Brígida Ramati P. Da Rocha and Tarek M. Habashy: Fractal Geometry, porosity and complex resistivity: from hand specimen to field data / Geological Society, London, Special Publications, 122:287-297, doi:10.1144/GSL.SP.1997.122.01.17 --- M. Ben Clennell: Tortuosity: a guide through the maze / Geological Society, London, Special Publications, 122:299-344, doi:10.1144/GSL.SP.1997.122.01.18 --- J. C. Lofts, J. Bedford, H. Boulton, J. A. van Doorn, and P. Jeffreys: Feature recognition and the interpretation of images acquired from horizontal wellbores / Geological Society, London, Special Publications, 122:345-365, doi:10.1144/GSL.SP.1997.122.01.19 --- D. Goldberg and Y. F. Sun: Scattering attenuation as a function of depth in the Upper Oceanic Crust / Geological Society, London, Special Publications, 122:367-375, doi:10.1144/GSL.SP.1997.122.01.20 --- N. Passas, C. Butenuth, and M. H. De Freitas: An application of the Moiré Method to a study of local strains during rock failure in tension / Geological Society, London, Special Publications, 122:377-388, doi:10.1144/GSL.SP.1997.122.01.21
    Pages: Online-Ressource (VII, 393 Seiten) , Illustrationen, Diagramme, Karten
    ISBN: 1897799810
    URL: http://sp.lyellcollection.org/content/122/1
    Language: English
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  • 2
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    GEOSTAR: a GEophysical and Oceanographic STation for Abyssal Research (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The GEOSTAR is a technological and scientific project aimed at the realisation of an autonomous benthic observatory able to perform long-term, continuous and integrated geophysical and environmental measurements in deep seafloors. The observatory is conceived to be a node of existing and future geophysical monitoring networks, making possible their extension offshore. The GEOSTAR observatory prototype hosts sensors for seismic, geomagnetic, gravimetric, geochemical and oceanographic researches up to abyssal depths (4000 m). The first 1-year scientific mission is foreseen within the end of the millennium in the abyssal plain (3400 m) of the Southern Tyrrhenian Sea, where key information about the geodynamics and oceanography of the whole Mediterranean basin can be acquired.
    Description: Published
    Description: 175-183
    Description: JCR Journal
    Description: reserved
    Keywords: Seafloor observatories ; Geophysics ; Water geochemistry ; Physical oceanography ; 03. Hydrosphere::03.01. General::03.01.08. Instruments and techniques ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 03. Hydrosphere::03.02. Hydrology::03.02.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
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    Interactive Exhibits for Geophysical Education: Uncovering the Secrets of the Earth (2008)
    WSEAS
    Details
    Publication Date: 2017-04-04
    Description: The Educational & Outreach Group of the Istituto Nazionale di Geofisica e Vulcanologia (INGV, Rome, Italy) designed a portable museum to bring on the road educational activities focused on the understanding of geomagnetism, plate tectonics, seismology and seismic hazard. Here the main experiments, models and exhibits which have been successfully installed in Genoa for the Science Festival (2003, 2004) and in Rome (2005) with enthusiastic audience participation are shown.
    Description: Published
    Description: 375-381
    Description: 5.8. TTC - Formazione e informazione
    Description: N/A or not JCR
    Description: open
    Keywords: Geophysics ; education ; geomagnetism ; plate tectonics ; seismology ; portable museum ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    Earth-prints Open Archive (2005)
    Details
    Publication Date: 2017-04-03
    Description: Geophysics Open archive. Free access to worldwide scientists during search and submission process. Earth-Prints is an open archive created and maintained by Istituto Nazionale di Geofisica e Vulcanologia with the collaboration of Programma Nazionale Ricerche in Antartide. It is maintained by CILEA .
    Description: Unpublished
    Description: Rome, Italy
    Description: open
    Keywords: Open Access ; Geophysics ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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  • 5
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    Geosystemics (2009)
    WSEAS Press
    Details
    Publication Date: 2017-04-04
    Description: For Geosystemics we define the science that studies the Earth system from a holistic point of view. Earth is thus considered as a whole and unique far-from-the equilibrium complex system, formed by numerous different parts (sub-systems), which do not act independently but interact each other continuously. Most interactions are nonlinear, so that we can usually say that “resultant is more than the sum of the parts”. Interactions are not only in terms of contrasts but, and mostly, cooperative and mutual organizations. We will see some aspects and properties of this approach with a few examples.
    Description: Published
    Description: Cambridge, UK, February 24-26, 2009
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: open
    Keywords: Geosystemics ; Earth system ; Nonlinear Analysis ; Entropy ; Geophysics ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 6
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    A multidisciplinary approach to the evaluation of the mechanism that triggered the Cerda landslide (Sicily, Italy) (2005)
    Elsevier
    Details
    Publication Date: 2020-03-02
    Description: The present paper describes a multidisciplinary approach to the evaluation of a seismically triggered landslide that occurred in the Cerda area (Italy) on September 6, 2002, about 1 h after an earthquake took place in the south Tyrrhenian Sea. The study was focused on an analysis of the role of the seismic input in triggering the landslide, in view of the evidence that no other mass movement was recorded in the adjacent areas despite geological and geomorphological spatial homogeneity. The studied area is located on a slope of the western flank of the Fiume Imera Settentrionale (Northern Sicily), which is made up of clayey–arenitic rocks. The slope inclines gently but is not uniform due to fluvial, gravitative, and rainwash processes. Field data dealing with global positioning system (GPS), geology, geomorphology, geophysics (vertical electrical sounding, or VES), and geochemistry (soil gas fluxes and composition) were acquired and analysed in order to investigate the cause–effect relationships between the earthquake and the mass movement. The GPS survey allowed us to map the ground failures that have also been classified on the basis of their kinematical meaning (i.e., compressive, distensive, or transcurrent structures). The geological analysis revealed outcropping rocks and tectonic structures. The geomorphologic survey highlighted the presence of preexisting landslide bodies. The geophysical survey detected a buried surface located at a depth of about 100 m . Finally, the geochemical survey showed that the gas released from the displaced mass came from a shallow depth and was not related to any active fault system. The abovementioned information allowed us to interpret the landslide event as a partial reactivation of a preexisting landslide body that was triggered by the earthquake.
    Description: Ministero dell’Istruzione, dell’Universita` e della Ricerca (MIUR), Cofinanziamento Progetti di Ricerca di Rilevante Interesse Nazionale (COFIN PRIN) 2002 Project "Valutazione dell’Erosione del Suolo in Ambiente Mediterraneo"
    Description: Published
    Description: 101–116
    Description: partially_open
    Keywords: Landslide ; Earthquake ; Geochemistry ; Geophysics ; GPS ; Triggering mechanism ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
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    Crustal accretion and evolution at slow and ultra-slow spreading mid-ocean ridges (2009)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-25
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2001
    Description: Half of the ocean crust is formed at spreading centers with total opening rates less than 40 km/Myr. The objective of this Thesis is to investigate temporal variations in active ridge processes and crustal aging at slow-spreading centers by comparing axial crustal structure with that on conjugate flanks of the slow-spreading Mid-Atlantic Ridge (MAR) (full rate, 20 km/Myr) and the ultra-slow spreading Southwest Indian Ridge (SWIR) (full rate, 14 km/Myr). Seismic refraction data collected along the rift valley and flanking rift mountains of the OH-l segment (35°N) at the MAR show that the entire crustal section is constructed within a zone that is less than 5 km wide. Shallow-level hydrothermal circulation within the axial valley is suggested by the rift mountain seismic profiles, which show that the upper crust is 20% thinner and 16% faster along strike than zero-age crust. These effects probably result from fissure sealing within the extrusive crust. Deeper crustal velocities remain relatively constant at the segment midpoint within the first 2 Myr, but are reduced near the segment offsets presumably by faulting and fracturing associated with uplift out of the rift valley. A temporal variation in axial melt supply is suggested by a 15% difference in along-strike crustal thickness between the rift valley and rift mountains, with relatively less melt supplied today than 2 Ma. Crustal accretion at the SWIR appears to occur in a similar manner as at the MAR, although gravity and seismic data indicate that the average crustal thickness is 2-4 km less at the ultra-slow spreading SWIR. A 25 Myr record on both flanks of the ridge shows that seafloor spreading has been highly asymmetric through time, with 35% faster crustal accretion on the Antarctic (south) plate. A small-offset non-transform discontinuity between two ridge segments is just as stable as two neighboring transform discontinuities, although a single mantle Bouguer gravity anomaly centered over the non-transform offset indicates that this boundary does not significantly perturb underlying mantle flow. Off-axis magnetic anomalies are recorded with high fidelity despite the very low spreading rates and the absence of a basaltic upper crust in one area. The lower crust may be the dominant off-axis carrier of the magnetic signal, contrary to traditional models of crustal magnetic structure. Morphological and gravity data show evidence of asymmetric crustal accretion across the SWIR ridge axis, with slightly warmer mantle temperatures beneath the slower-spreading African (north) plate.
    Description: Funding was provided by the National Science Foundation through Contract No. OCE-9300450 and by the Joint Oceanographic Institutions through Subcontract No. JSC1-00.
    Keywords: Earth ; Crust ; Geophysics ; Maurice Ewing (Ship) Cruise EW96-08 ; Yokosuka (Ship) Cruise ; Kairei (Ship) Cruise ; Conrad (Ship) Cruise RC2709
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
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  • 8
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    Applications of time series analysis to geophysical data (2007)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-25
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June, 1980
    Description: This thesis consists of three papers applying the techniques of time series analysis to geophysical data. Surface wave dispersion along the Walvis Ridge, South Atlantic Ocean, is obtained by bandpass filtering the recorded seismogram in the frequency domain. The group velocity is anomalously low in the period range of 15-50 s, and formal inversion of the data indicates both crustal thickening to 12.5 km and low shear velocity (4.25-4.35 km/s) to depths of 40-50 km. The electromagnetic induction fields at a deep ocean site northeast of Hawaii were used to determine the electrical conductivity of the earth to 400 km depth. Singular value decomposition of the data matrix indicates three degrees of freedom, suggesting source field complications and a two dimensional conductive structure. Inversion of one of the principal terms in the response function shows an abrupt rise in electrical conductivity to 0.05 mho/m near 160 km with no resolvable decrease below this. A model study suggests that moving source fields influence the induction appreciably in the other principal response tunction. A set of piston cores from the northeast Atlantic Ocean are used to construct paleomagnetic time series covering the interval 25-127 kybp. Stratigraphic control is provided by counts of planktonic toraminifera, and empirical orthogonal function analysis shows a significant decrease in sedimentation rate at the interglaciai/glacial transition. The sediments are magnetically stable and reliable relative paleointensity measurements could be obtained. Spectral analysis of the directions reveals a predominant 10 ky periodicity and no dominant looping direction.
    Description: I was supported for the early parts of this work by a NSF Graduate Fellowship. The Walvis Ridge study was supported by the WHOI Education Office and the Defense Advanced Research Projects Agency. The induction study was funded by the NSF under grants OCE74-12730 and OCE77-8633, and by the WHOI Ocean Industries Program. The paleomagnetic study was supported by NSF contracts OCE77-82255 and ÖCE79-19258.
    Keywords: Geomagnetism ; Electromagnetic fields ; Marine sediments ; Paleomagnetism ; Geophysics ; Marine geophysics ; Atlantis II (Ship : 1963-) Cruise AII94
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
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  • 9
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    Detailed studies of the structure, tectonics, near bottom magnetic anomalies and microearthquake seismicity of the Mid-Atlantic Ridge near 37°N (2006)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-25
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September, 1975
    Description: The Mid-Atlantic Ridge is one of the most well known and yet poorly understood spreading centers in the world. A detailed investigation of the Mid-Atlantic Ridge crest near 37°N (FAMOUS) was conducted using a deeply towed instrument package. The objective was to study the detailed structure and spreading history of the Mid-Atlantic Ridge median valley, to explore the roles of volcanism and faulting in the evolution of oceanic crust, and to study the morphologic expression and structural history of the zone of crustal accretion. In addition, microearthquake surveys were conducted using arrays of free-floating hydrophones. The most recent expression of the accreting plate boundary in the Famous Rift is an alternating series of linear central volcanoes and depressions 1.5 km wide which lie within the inner floor. This lineament is marked by a sharp maximum in crustal magnetization only 2-3 km wide. Magnetic studies indicate that over 90% of the extrusive volcanism occurs within the rift inner floor, a zone 1 to 12 km wide, while volcanism is extremely rare in the rift mountains. Volcanoes created in the inner floor are transported out on, block faults, becoming a lasting part of the topography. Magnetic anomaly transition widths vary from 1 km to 8 km with time and appear to reflect a bi-stable median valley structure. The valley has either a wide inner floor and narrow terraces, in which case the volcanic zone is wide and magnetic anomalies are poorly recorded (wide transition widths); or it has a narrow inner floor and wide terraces, the volcanic zone is then narrow and anomalies are clearly recorded (narrow transition widths). The median valley of any ridge segment varies between these two structures with time. At present the. Famous Rift has a narrow inner floor and volcanic zone (1-3 km) while the south Famous Rift is at the opposite end of the cycle with a wide inner floor and volcanic zone (10-12 km). Over 95% of the large scale (〉2 km) relief of the median valley is accounted for by normal faults dipping toward the valley axis. Normal faulting along fault planes dipping away from the valley begins just past the outer walls of the valley. Outward facing normal faulting accounts for most of the decay of median valley relief in the rift mountains while crustal tilting accounts for less than 20%. The pattern of normal faulting creates a broad, undulating horst and graben relief. Volcanic features contribute little to the large scale relief, but contribute to the short wavelength (〈2km) roughness of the topography. Spreading in the Famous area is highly asymmetric with rates twice as high to the east as to the west. At 1.7 m.y.b.p. the sense of asymmetry reverses in direction with spreading faster to the west, resulting in a gross symmetry when averaged through time. The change in spreading asymmetry occurred in less than 0.15 m.y. Structural studies indicate that the asymmetric spreading is accomplished through asymmetric crustal extension as well as asymmetric crustal accretion. Spreading in the Famous area is 17° oblique. Even on a fine scale there is no indication of readjustment to an orthogonal plate boundary system. Spreading has been stably oblique for at least 6 m.y., even through a change in spreading direction. Magnetic studies reveal that the deep DSDP hole at site 332 was drilled into a magnetic polarity transition, and may have sampled rocks which recorded the earth i s field behavior during a reversal. The presence of negative polarity crust within the Brunhes normal epoch in the inner floor has been determined, and may be due to old crust left behind or recording of a geomagnetic field event. Crustal magnetization decays to lie of its initial value in less than 0.6 m.y. The rapid decay may be facillitated by very intense crustal fracturing observed in the inner floor. Microearthquake, magnetic and structural studies indicate that both the spreading and transform plate boundaries are very narrow (1-2 km) and well-defined for short periods, but migrate over zones 10-20 km wide through time.
    Keywords: Submarine geology ; Geophysics ; Geomorphology ; Plate tectonics ; Knorr (Ship : 1970-) Cruise KN31
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
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  • 10
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    MapTool version 2 : user’s manual (2006)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: MapTool is an interactive computer program for the display of common marine geophysical data. At present, the program displays isolines, color-filled contours, navigation tracklines, and navigated scalar values in a variety of styles. A variety of map projections are supported. This document describes the basic requirements for running the MapTool program, for creating various displays, and generating hard copy output. The supported data file formats are described. All of the options, displays, menus, and windows are documented.
    Description: Funding was provided by the Office of Naval Research under Grant N00014-90-J-1621.
    Keywords: Mapping ; Geophysics ; Digital display software
    Repository Name: Woods Hole Open Access Server
    Type: Technical Report
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  • 11
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    Experiments in a rotating source-sink annulus (2006)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution August, 1971
    Description: An experimental investigation of the different flow regimes in a rotating source-sink annulus is described. Both the steady and transient velocities are measured over a large range of Ekman Reynolds number and Rossby number. Differing probe configurations are used to investigate the corresponding motions in spatially separated regions of the annulus. The steady interior circulation field exhibits a strong dependence on the imposed flux values. The non-dimensional circulation increases with radius over a certain radial range for higher system Rossby number. The observed profile changes are related to the existence of an unstable Ekman layer at some inner radial position. The thickness of the observed Ekman layers is typically 85% of the theoretical scale height. For higher local Reynolds number (ReL), the thickness is generally much smaller. The width of the sidewall boundary layer adjacent to the sink increases with larger system Rossby number. Adjacent to the source, the radial boundary layer is wider than that at the sink wall. Observed oscillations are separable into three types. For ReL 〉 50, instability waves are observed in the Ekman layer flow. In the same Re range, inertial oscillations are detected in the interior region of the annulus. The observed inertial wave frequency at differing radial positions is explained by incorporating Doppler shift corrections and taking account of the steady circulation profiles. The radial wavelength of the inertial waves corresponds to the length of the Class A Ekman layer instabi1ity. For small values of Re and local Rossby number, an axisymmetric disturbance, with a characteristic frequency slightly greater than therotation rate, is observed at the outer radial positions.
    Keywords: Geophysics ; Fluid models
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
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  • 12
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    Geophysical fluid dynamics : notes on the 1960 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 60-46, series later renamed WHOI-.
    Description: National Science Foundation under Research Grant NSF 12556
    Keywords: Geophysics ; Fluid dynamics
    Repository Name: Woods Hole Open Access Server
    Type: Technical Report
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  • 13
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    1982 summer study program in geophysical fluid dynamics : particle motions in fluids (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: The (Lagrangian) motion of a fluid particle was contrasted with the (Eulerian) flow past a fixed point in space during this twenty-fourth summer program in geophysical fluid dynamics at the Woods Hole Oceanographic Institution.
    Description: Office of Naval Research under Contract N00014-82-G-0079 and National Science Foundation Grant MCS-82-00450. Partial support from the Center for Analysis of Marine Systems (CAMS) at Woods Hole Oceanographic Institution.
    Keywords: Geophysics ; Fluid dynamics
    Repository Name: Woods Hole Open Access Server
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  • 14
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    The 1960 Summer Program of Theoretical Studies in Geophysical Fluid Dynamics (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 60-46, series later renamed WHOI-.
    Description: This ten-week work-study-discussion program is centered about a formal course called Geophysical Fluid Dynamics. Eight participants are selected from graduate and postgraduate applicants. In the discussions emphasis is placed on the formulation of tractable research problems in geophysics. The participants are encouraged to work on satisfactory problems thus formulated and to continue with their research after returning to their respective institutions.
    Description: National Science Foundation under Research Grant NSF 12556
    Keywords: Geophysics ; Fluid models ; Fluid dynamics
    Repository Name: Woods Hole Open Access Server
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    The 1959 Summer Program of Theoretical Studies in Geophysical Fluid Dynamics (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 59-53, series later renamed WHOI-.
    Description: This ten-week work-study-discussion program is centered about a formal course called Geophysical Fluid Dynamics. Eight participants are selected from graduate and postgraduate applicants. In the discussions emphasis is placed on the formulation of tractable research problems in geophysics. The participants are encouraged to work on satisfactory problems thus formulated and to continue with their research after returning to their respective institutions.
    Description: National Science Foundation under Research Grant NSF G-9125
    Keywords: Fluid dynamics ; Geophysics ; Fluid models
    Repository Name: Woods Hole Open Access Server
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    Geophysical fluid dynamics : notes on the 1961 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference no. 61-39, series later renamed WHOI-.
    Description: National Science Foundation under Research Grant NSF G-16973
    Keywords: Geophysics ; Fluid models ; Fluid dynamics
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    1980 summer study program in geophysical fluid dynamics : coherent features in geophysical flows (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Four principal lecturers shored the task of presenting the subject "Coherent Features in Geophysical Flows" to the participants of the twenty-second geophysical fluid dynamics summer program. Glenn Flierl introduced the topic and the Kortweg-de Vries equation via a model of finite amplitude motions on the beta plane. He extended the analysis to more complex flows in the ocean and the atmosphere and in the process treated motions of very large amplitude. Larry Redekopp's three lectures summarized an extensive body of the mathematical literature on coherent features. Andrew Ingersoll focussed on the many fascinating features in Jupiter's atmosphere. Joseph Keller supplemented an interesting summary of laboratory observations with suggestive models for treating the flows.
    Description: Office of Naval Research under Contract N00014-79-C-0671
    Keywords: Geophysics ; Fluid dynamics
    Repository Name: Woods Hole Open Access Server
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    Summer study program in geophysical fluid dynamics : dynamic differentation (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Those attending G.F.D. 1984 were introduced to the novel topic of Geological Fluid Mechanics by our Principal Lecturer, Herbert Huppert. He presented his studies both as a discipline with recent fascinating successes, and as a challenge to his listeners to further isolate mathematically tractable examples of these multi-component flows. Geological Fluid Mechanics has been the responsible process for the formation and modification of most of the geological objects studied today. The dynamics of fluid mixtures in magma chambers, the changing fluid boundary conditions and composition during selective crystallization of parts of the melt, and the separation of fluid fractions of different density and viscosity all represent areas in which quantitative theories are currently being tested. However, equally many areas, including convection mechanisms in the Earth's core and quantitative predictions for upper mantle motion, resist simplistic modeling.
    Description: Office of Naval Research under contract N00014-82-G-0079 and the National Science Foundation under Grant MCS-82-800450. Partial support acknowledged from the Center for Anatysis of Marine Systems (CAMS) at the Woods Hole Oceanographic Institution. CAMS is supported by The Exxon Foundation, Mobil Foundation, Inc., The Ambrose Monell Foundation, The R. R. Mellon Family Foundation., the Atlantic Richfield Foundation, and by an anonymous donor.
    Keywords: Geophysics ; Fluid dynamics
    Repository Name: Woods Hole Open Access Server
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  • 19
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    Summer study program in geophysical fluid dynamics : chaos (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: The explosive growth of dynamieal systems theory in the past two decades stems in large part from the realization that it is applicable to many natural phenomena. Indeed, much o f the theoretical development has been sparked by numerical and laboratory experiments which exhibit ordered sequences of behavior that call for a general framework of interpretation We have been fortunate this summer to have had in residence both pioneers and developers of dynamical systems theory and its applications to fluid mechanics. Several recent texts contain the basic principles that Ed Spiegel used as a springboard for five lectures in which he exposed us to elementary examples of bifurcation and chaos, to symmetry breaking, normal forms and temporal and spatial disorder, as well as to pertinent fluid mechanical and astrophysical phenomena. Yves Pomeau continued the development with an elegant summary of different types of intermittency . Stephan Fauve agree to write up his impressive seminars on phase instability and turbulence as an extension of the lecture series. Many of the remaining seminars introduced new concepts in the theory, some with specific examples, others via mathematical development, and still others through ways of interpreting the data that emerge from calculations and experiments. As an outstanding example of this, Albert Libchaber has demonstrated the fascinating correspondence between the frequencies observed in one of his recent fluid mechanics experiments and results from number theory relating the Fibonacci series to the golden mean.
    Description: Office of Naval Research under contract NO0014-82-6-0079 and the National Science Foundation under Grants MCS-82-000450 and DMS-85-04166.
    Keywords: Geophysics ; Fluid dynamics
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  • 20
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    Notes on the 1963 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 63-34, series later renamed WHOI-.
    Description: This year's lectures by Derek Moore form a detailed report of investigations on the fluid motion caused by the motion of a body in a homogeneous rotating fluid. The emphasis has been on the significance of the Taylor-Proudman theorem and the departure of the fluid from the behavior described by the Taylor-Proudman theorem. The plan was to probe deeply into one problem and thereby acquire information in a wider area of study of rotating fluids.
    Description: National Science Foundation under Research Grant NSF GE-15l8
    Keywords: Geophysics
    Repository Name: Woods Hole Open Access Server
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  • 21
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    Notes on the 1966 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 66-46, series later renamed WHOI-.
    Description: The lecturers, Drs. Howard, Stern and Veronis, have introduced the participants to several aspects of geophysical fluid dynamics at the frontiers of current research. Their choice of topic and its development was to serve, on one hand, a pedagogic function and, on the other, to suggest a variety of allied unsolved problems.
    Description: National Science Foundation
    Keywords: Geophysics
    Repository Name: Woods Hole Open Access Server
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  • 22
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    Notes on the 1965 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 65-51, series later renamed WHOI-.
    Description: National Science Foundation
    Keywords: Geophysics
    Repository Name: Woods Hole Open Access Server
    Type: Technical Report
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  • 23
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    Notes on the 1968 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 68-72, series later renamed WHOI-.
    Description: The general circulation of the oceans was the topic of concentration for the 1968 WHOI Summer Program in Geophysical Fluid Dynamics
    Description: National Science Foundation
    Keywords: Ocean circulation ; Geophysics ; Fluid models
    Repository Name: Woods Hole Open Access Server
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  • 24
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    Notes on the 1969 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 69-41, series later renamed WHOI-.
    Description: The principal theme of this eleventh Summer Program has been Astrophysical Fluid Dynamics. As in the past, we have explored the region of overlap in technique and theory of our summer theme and other aspects of Fluid Dynamics. An interesting example of this overlap is the application of the physics of salt-finger instability, a significant oceanographic process, to instabilities due to differential rotation in the sun, a critical problem in stellar evolution.
    Description: National Science Foundation
    Keywords: Geophysics ; Ocean circulation
    Repository Name: Woods Hole Open Access Server
    Type: Technical Report
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  • 25
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    Notes on the 1975 summer study program in geophysical fluid dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: The central topic of this seventeenth Geophysical Fluid Dynamics program was fluid motion in the earth's mantle and core. Our principal lecturer, Dan McKenzie, first addressed himself to the task of separating solid behavior of the mantle from fluid behavior. When the level of protest diminished Dan advanced to his numerical studies of mantle convection. The relationship of these numerical experiments and geophysical observables was impressive indeed for this first generation of mantle modeling. Intertwined seminars from P. Molnar, B. Parsons, J. Sclater and T. Atwater exposed us to data gathering and its rationale at the frontiers of geophysics. The fluid properties of the core may be less suspect than those of the mantle, but how and why the core fluid moves is still a mystery. Our associate principal lecturer, Fritz Busse, discussed the geomagnetic evidence for core motion. Then moving quickly to the more abstract problems of model geodynamos, Fritz described in five lectures his achievement of a first complete dynamic dynamo driven by convection.
    Description: National Science Foundation
    Keywords: Geophysics
    Repository Name: Woods Hole Open Access Server
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  • 26
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    Notes on the 1978 summer study program on dynamo models of geomagnetism in geophysical fluid dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: This was the twentieth Geophysical Fluid Dynamics program at Woods Hole. Stephen Childress of the Courant Institute was our principal lecturer. Dynamo theory, with all its interdisciplinary facets was our central theme. Geomagnetism and the solar magnetic cycle were brought closer to comprehension, yet none claimed a detailed predictive theory was near at hand. Perhaps J. Keller's lecture, entitled "Smooth equations for rough problems", best characterized the nature of these studies. Even then, the smooth equations are quite nonlinear, with Finite-amplitude magnetic solutions yet to be explored. Lectures intertwined with those of Childress exposed us to topics beside and outside his emphasis on a convective geodynamo.
    Description: Office of Naval Research under Contract N00014-78-G0072
    Keywords: Geophysics ; Fluid dynamics
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  • 27
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    Enceladus' south polar sea (2007)
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Icarus 189: 72-82, doi:10.1016/j.icarus.2007.01.010.
    Description: Recent observations of the south pole of Saturn’s moon Enceladus by the Cassini spacecraft have revealed an active world, powered by internal heat. In this paper, we propose that localized subsurface melting on Enceladus has produced an internal south polar sea. Evidence for this localized sea comes from the shape of Enceladus, which does not match a differentiated body at its current orbital position. We show that melting induced by the observed heat flow at the south pole produces a large enough pit to match the shape of Enceladus with a differentiated rock and ice interior. Numerical modeling of melting and ice flow shows that the sea produced beneath the south pole is stable against inflow of ductile ice from its surroundings for the duration of the heating. The shape modification due to melting also produces a negative degree-two gravity anomaly, which can reorient the spin axis of Enceladus in order to place the sea at the pole.
    Keywords: Enceladus ; Satellites ; Shapes ; Interiors ; Geophysics
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 28
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    Notes on the 1967 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2008)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 67-54
    Description: In former years some of the research and seminars of the WHOI Geophysical Fluid Dynamics program was concerned with determining the interior structure and motions of stars and galaxies. This year we have focused our attention downward rather than upward and have attempted to learn some things about the earth's interior. Freeman Gilbert's lectures on the inverse problem in seismology discuss one aspect of the geophysicist's attempts to infer some things about the earth's interior from the evidence which is available at the surface. Paul Robert presented a survey of the difference attempts to attribute the earth's magnetic field to dynamo action. Willem Malkus, Raymond Hide and Stephen Childress supplemented Roberts' lectures with seminars. As students of our physical environment all of us were entertained and stimulated by this introduction to the netherworld.
    Description: National Science Foundation
    Keywords: Geophysics
    Repository Name: Woods Hole Open Access Server
    Type: Technical Report
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  • 29
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    The 1961 Summer Program of Theoretical Studies in Geophysical Fluid Dynamics (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 61-39, series later renamed WHOI-.
    Description: This ten-week work-study-discussion program was centered about a formal course called Geophysical Fluid Dynamics. Sixteen participants were selected from graduate and postgraduate applicants. In the discussions emphasis was placed on the formulation of tractable research problems in geophysics. The participants were encouraged to work on satisfactory problems thus formulated and to continue with their research after returning to their respective institutions.
    Description: National Science Foundation under Research Grant NSF G-16973
    Keywords: Geophysics ; Fluid models ; Fluid dynamics
    Repository Name: Woods Hole Open Access Server
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  • 30
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    Notes on the 1962 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 62-33, series later renamed WHOI-.
    Description: National Science Foundation under Research Grant NSF22332
    Keywords: Geophysics ; Fluid dynamics
    Repository Name: Woods Hole Open Access Server
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  • 31
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    The 1962 Summer Program in Geophysical Fluid Dynamics (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 62-38, series later renamed WHOI-.
    Description: Includes the preprint "Mixing-length Analyses of Turbulent Thermal Convection at Arbitrary Prandtl Number" - R. Kraichnan (1962). N.Y.U. Research Report No. HSN-6.
    Description: National Science Foundation under Research Grant NSF22332
    Keywords: Geophysics ; Fluid dynamics
    Repository Name: Woods Hole Open Access Server
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  • 32
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    Lake Kivu expedition : geophysics, hydrography, sedimentology (preliminary report) (2008)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: In March 1971, seven members of the Woods Hole Oceanographic Institution were engaged in a multidisciplinary study of Lake Kivu. This expedition represents part of a long-range program concerned with the structural and hydrographical settings of the East African Rift Lakes and their relationships to the Red Sea and the Gulf of Aden Rifts. The program started in May 1963 with a geophysical study on Lake Malawi (von Herzen and Vacquier, 1967). Several expeditions of our Institution into the Red Sea and Gulf of Aden area in 1964, 1965 and 1966 (Degens and Ross, 1969) provided detailed geological information on the "northern" extension of the East African Rift. And finally our study of last year on Lake Tanganyika c1osed a major gap in the program; it allowed us to out1ine a model on the evolution of a rift which starts with (i) bulging of the earth's crust, (ii) block-faulting, (iii) volcanism and hydrothermal activity, and which has its final stage in (iv) sea floor spreading (Degens et al. 1971). In the case of Lake Tanganyika, only the second stage of this evolution series has been reached, i.e. block-faulting. In contrast, the Red Sea and the Gulf of Aden had already evolved to active sea floor spreading, almost 25 million years ago. Somewhere along the line between Lake Tanganyika and the Gulf of Aden must lie the "missing link" of this evolution series. Lake Kivu, almost 100 miles to the north of Lake Tanganyika is situated at the highest point of the Rift Valley and is surrounded by active volcanoes and geothermal springs. As recently as 1944, lava flows reached the lake shore. This lake was therefore, a natural choice to test our hypothesis on the origin and development of rifts. Furthermore, the occurrence of large quantities of dissolved gases, e.g., CO2 and methane, represented an interesting geochemical phenomenon worthwhile to investigate.
    Description: Supported by the National Science Foundation with Grants GA 19262, GB 20956, and GU 3927; grants from the Petroleum Research Fund of the American Chemical Society PRF#1943A2; and by private research funds of the Woods Hole Oceanographic Institution.
    Keywords: Geophysics ; Hydrography ; Sedimentology
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  • 33
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    Notes on the 1964 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Originally issued as Reference No. 64-46, series later renamed WHOI-.
    Description: Two distinctive features of large-scale geophysical flows are that they are dominated by the earth's rotation and that they are turbulent. This year's lecture program was an exploration of recent achievements in the study of, first, the simplest examples of turbulence, and second, the rotational constraint.
    Description: National Science Foundation and Travelers' Research Center, Inc
    Keywords: Geophysics
    Repository Name: Woods Hole Open Access Server
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  • 34
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    Notes on the 1973 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Nonlinear wave interactions formed the theme of the fifteenth summer program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution. Owen Phillips was our principal lecturer on this subject, He chose to emphasize interactions among small numbers of discrete wave modes, including both internal and surface gravity waves in his discussions. His lectures provided a stimulating introduction to this important subject. Phillips' lectures were supplemented by a lecture by William Simmons on experiments with interacting internal waves, and a lecture by Carl Wunsch on internal waves in the ocean. Later in the summer, Wunsch gave us a lecture series on practical time-series analysis.
    Description: We thank the National Science Foundation for their continuing support.
    Keywords: Geophysics ; Fluid models
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  • 35
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    Notes on the 1972 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: The effect of gravity on fluids of varying density is of fundamental importance in natural flows. This subject formed the topic of concentration for the fourteenth summer program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution. We had the good fortune to hear Stewart Turner lecture on stratified flows just after he had completed the manuscript for his book on the subject. Turner chose to emphasize nonlinear and turbulent aspects of stratified flows and, therefore, had to give up the deductive approach in favor of treatments based on dimensional analysis and similarity arguments. This summary of the many experimental studies of these flows increased our awareness of the fascinating variety of phenomena in which stratification plays so vital a role.
    Description: Supported by the Division of Fluid Dynamics, Oceanography and Applied Mathematics of the Office of Naval Research.
    Keywords: Geophysics
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  • 36
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    Notes on the 1974 summer study program in geophysical fluid dynamics at the Woods Hole Oceanographic Institution (2009)
    Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: This year the central topic was the general circulation of the oceans. Some of the basic ideas used in wind-driven and thermohaline studies were presented in the introductory course of lectures and simple models that have guided our thinking in the development of the topic were discussed. As part of the introductory lectures Peter Niiler developed a model of the mixed layer, exploring the reasoning and the parameterization behind the theories of this important boundary region at the surface of the ocean. Dennis Moore gave a careful account of transient flows in equatorial regions and showed how dynamical conditions on the eastern and western boundaries are satisfied by a superposition of planetary, Kelvin and Yanai waves. Peter Rhines concluded the series with a discussion of topographically induced low frequency motions. At the request of the students Joseph B. Keller gave a lecture on "Solution of Partial Differential Equations by Ray Theory".
    Description: National Science Foundation
    Keywords: Geophysics
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  • 37
    Electronic Resource
    Electronic Resource
    The importance of radioactivity in geoscience and mining (1995)
    Springer
    Cellular and molecular life sciences 51 (1995), S. 703-709 
    Details
    ISSN: 1420-9071
    Keywords: Geophysics ; geology ; natural radioactivity ; radiometry ; mining ; uranium ores ; radon ; disposal of radioactive waste
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Almost simultaneously with Roentgen rays, natural radioactivity was discovered. Its investigation led to important fundamentals of the geosciences: petrophysics, terrestrial heat flow, isotope geology, and absolute geological chronology. In applied geophysics and geology, exploration of radioactive ores and of tectonic faults, and radiometric well loggings, are used. Production of radioactive water and mining for uranium ores are discussed, including their development (especially in the Saxon ore mountains) and the consequences on health (radon in underground air and houses). Disposal of radioactive waste is touched on briefly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01941267
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  • 38
    Electronic Resource
    Electronic Resource
    The role of the Hermanus Magnetic Observatory in geomagnetic field research (1995)
    Springer
    Astrophysics and space science 230 (1995), S. 439-456 
    Details
    ISSN: 1572-946X
    Keywords: Geophysics ; geomagnetic field
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Geomagnetic field research carried out at the Hermanus Magnetic Observatory over the past decade is reviewed. An important aspect of this research has been the study of geomagnetic field variations, with particular emphasis on ULF geomagnetic pulsations. Features of geomagnetic pulsations which are unique to low latitude locations have been investigated, such as the cavity mode nature of low latitude Pi 2 pulsations and the role played by ionosphericO + ions in the field line resonances responsible for Pc 3 pulsations. A theoretical model has been developed which is able to account for the observed relationships between geomagnetic pulsations and oscillations in the frequency of HF radio waves traversing ionospheric paths. Other facets of the research have been geomagnetic field modelling, aimed at improving the accuracy and resolution of regional geomagnetic field models, and the development of improved geomagnetic activity indices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00658201
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  • 39
    Electronic Resource
    Electronic Resource
    An Approach to a Visual Language for Convective Fluid Flows: Visualization of Geophysical Simulations (1998)
    Springer
    Visual geosciences 3 (1998), S. 1-19 
    Details
    ISSN: 1610-2924
    Keywords: Geophysics ; Numerical modelling ; Visualization ; Language ; Convection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract It was known that deep within numbers and binary data from simulations of geophysical convective flows resided various patterns. Two models of convective fluid flows were being considered. One was a model of two-dimensional (768 × 256) air convection with finite Prandtl number of one and Rayleigh number of 108−1010, and another was a model of three-dimensional (up to 120 × 120 × 90) mantle convection with infinite Prandtl number and Rayleigh number of 106−108. Clearly, phenomena existed which superceded each individual dimensionless computer model to provide a piece of information regarding actual fluid flows. The problem was how to find, prove, and communicate these patterns and phenomena for convection simulations with gigabytes of data. In a search for such an analytical and communicative tool, the alternative of visualization was considered. The need for visualization was recognized and discussed. Then, utilizing both two- and three-dimensional models of high Rayleigh number convection, basic techniques of style and content were developed. Applications of the visualization techniques were designed utilizing IBM’s Data Explorer in order to create communicative images and movies, and after the applications, the problems of data storage and transfer became apparent. Throughout the process though, it became clear how important the language of vision actually could be in the geophysics community. In a field in which words such as plumes and internal waves have in ways replaced mathematics as the basic language for science, there is a need for another resource, another language-the visualization of convective fluid flows.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10069-998-0001-3
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  • 40
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    Initiation of plate boundary slip in the Nankai Trough off the Muroto peninsula, southwest Japan (2005)
    In:  Geophys. Res. Lett., Taipei, EGS, vol. 32, no. 12, pp. 1474-1482, pp. L12306, (ISSN: 1340-4202)
    Details
    Publication Date: 2005
    Keywords: Subduction zone ; Plate tectonics ; decollement ; Geol. aspects ; Ocean Drilling Program ; GRL ; 0500 ; Computational ; Geophysics ; (3200, ; 3252, ; 7833) ; 0900 ; Exploration ; Geophysics ; 3000 ; Marine ; Geology ; and ; Geophysics ; 8000 ; Structural ; Geology ; 8100 ; Tectonophysics
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    BIBLIOGRAPHY SEISMOLOGY
  • 41
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    Lidar measurements at Lauder, NZ (1995)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: In March of 1994, the GSFC Stratospheric Ozone Lidar was deployed to the Network for the Detection of Stratospheric Change (NDSC) site at Lauder, NZ. This was in conjunction with a series of NASA ER-2 flights from Christchurch, NZ south to the Antarctic Circle. These flights were organized to study the chemistry of the stratosphere before, during and after the formation of the well-known 'ozone hole'. Lidar measurements were made at four different time periods corresponding to the times of the ER-2 flights. Lauder is situated nearly along the flight path as the aircraft flew south and so the lidar measurements provide a checkpoint for the ozone, aerosol and temperature instruments onboard the aircraft. Whenever the weather permitted, lidar measurements were made as near to dawn, prior to the flight, and as near to sunset, after the flight. This provided data as close to the aircraft transit time as possible. More than 70 individual lidar measurements were made, each consisting of a vertical profile of ozone, temperature, and aerosol. These were made over three different seasons and show seasonal variation. Of particular interest in the lidar data base is the wintertime stratospheric - mesospheric temperature profiles, which show large variations at the stratopause and also some significant wave activity.
    Keywords: Geophysics
    Type: Optical Remote Sensing of the Atmosphere, Volume 2; 191-192; LC-95-67220
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    NASA TECHNICAL REPORTS
  • 42
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    Comparison of HALOE O3 and H2O observations from UARS with ground and balloonborne measurements (1995)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: The HALogen Occultation Experiment (HALOE) was launched on the Upper Atmosphere Research Satellite (UARS) by the Space Shuttle Discovery at 7:11:04 EDT on September 12, 1991. After allowing for a period of outgassing, HALOE began taking routine science observations on October 11. HALOE uses the experiment approach of solar occultation and the gas filter and broad band radiometer instruments techniques to measure vertical profiles of HCl, HF, CH4, NO, NO2, H2O, O3, aerosol, and temperature versus pressure. The measurements cover a broad altitude range from the upper troposphere in some cases to the lower thermosphere in the case of nitric oxide. Latitude coverage provided by the occultation geometry ranges from 80 deg S to 80 deg N over the course of one year. The experiment has operated essentially without flaw for more than three years. Instrument stability over this time, as judged by the maximum signal change when viewing the sun exoatmospherically is less than or equal to 2 to 3%.
    Keywords: Geophysics
    Type: ; 22-23
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    Accelerated line-by-line calculation of spectral absorption coefficients with high numerical accuracy (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: To model radiative transfer through the atmosphere with high accuracy, one must resort to the calculation of spectral absorption coefficients on a line-by-line basis. The calculation of these coefficients is computationally expensive for three reasons: (1) thousands of spectral lines can contribute to absorption at a single frequency; (2) the tails of spectral line profiles are long (i.e., a given line can contribute to absorption over a wide range of frequencies); and (3) the sampling frequencies at which monochromatic radiances are to be calculated must be spaced sufficiently close together to resolve the thinnest lines of interest (e.g., those that arise in the stratosphere). We have developed a new algorithm to accelerate the calculation of spectral absorption coefficients while retaining high numerical accuracy.
    Keywords: Geophysics
    Type: ; 68-70
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    Aerosol and cloud observations from the Lidar In-space Technology Experiment (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The Lidar In-Space Technology Experiment (LITE) is a backscatter lidar built by NASA Langley Research Center to fly on the Space Shuttle. The purpose of the program was to develop the engineering processes required for space lidar and to demonstrate applications of space lidar to remote sensing of the atmosphere. The instrument was flown on Discovery in September 1994. Global observations of clouds and aerosols were made between the latitudes of 57 deg N and 57 deg S during 10 days of the mission.
    Keywords: Geophysics
    Type: ; 24
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    An overview of the SABER experiment for the TIMED mission (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) experiment has been selected for flight on the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) mission expected to fly in the latter part of this decade. The primary science goal of SABER is to achieve fundamental and important advances in understanding of the energetics, chemistry, and dynamics, in the atmospheric region extending from 60 km to 180 km altitude, which has not been comprehensively observed on a global basis. This will be accomplished using the space flight proven experiment approach of broad spectral band limb emission radiometry. SABER will scan the horizon in 12 selected bands ranging from 1.27 microns to 17 microns wavelength. The observed vertical horizon emission profiles will be mathematically inverted in ground data processing to provide vertical profiles with 2 km vertical resolution, of temperature, O3, H2O, NO, NO2, CO, and CO2. SABER will also observe key emissions needed for energetics studies at 1.27 microns (O2((sup 1)delta)), 2 microns (OH(v = 7,8,9)) 1.6 microns (OH(v = 3,4,5)), 4.3 microns (CO2(v(sub 3))) 5.3 microns (NO) 9.6 microns (O3), and 15 microns (CO2(v(sub 2))). These measurements will be used to infer atomic hydrogen and atomic oxygen, the latter inferred three different ways using only SABER observations. Measurements will be made both night and day over the latitude range from the southern to northern polar regions.
    Keywords: Geophysics
    Type: ; 5-7
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    Global Simulations of Magnetotail Reconnection (2007)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: There is a growing number of observational evidences of dynamic quasi-periodical magnetosphere response to continuously southward interplan etary magnetic field (IMF). However, traditional global MHD simulatio ns with magnetic reconnection supported by numerical dissipation and ad hoc anomalous resistivity driven by steady southward IMF often prod uce only quasi-steady configurations with almost stationary near-eart h neutral line. This discrepancy can be explained by the assumption that global MHD simulations significantly underestimate the reconnectio n rate in the magnetotail during substorm expansion phase. Indeed, co mparative studies of magnetic reconnection in small scale geometries demonstrated that traditional resistive MHD did not produce the fast r econnection rates observed in kinetic simulations. The major approxim ation of the traditional MHD approach is an isotropic fluid assumption) with zero off-diagonal pressure tensor components. The approximatio n, however, becomes invalid in the diffusion region around the reconn ection site where ions become unmagnetized and experience nongyrotropic behaviour. Deviation from gyrotropy in particle distribution functi on caused by kinetic effects manifests itself in nongyrotropic pressu re tensor with nonzero off-diagonal components. We use the global MHD code BATS-R-US and replace ad hoc parameters such as "critical curren t density" and "anomalous resistivity" with a physically motivated di ssipation model. The key element of the approach is to identify diffusion regions where the isotropic fluid MHD approximation is not applic able. We developed an algorithm that searches for locations of magnet otail reconnection sites. The algorithm takes advantage of block-based domain-decomposition technique employed by the BATS-R-US. Boundaries of the diffusion region around each reconnection site are estimated from the gyrotropic orbit threshold condition, where the ion gyroradius is equal to the distance to the reconnection site. Inside diffusion regions ions are treated as nongyrotropic fluid with nonzero off-dia gonal components of the pressure tensor. The primary kinetic mechanism controlling the dissipation in the diffusion region is incorporated into global MHD simulations in terms of spatially localized nongyrotropic corrections to the induction equation. The magnitude of the non-g yrotropic corrections to the electric field and spatial scales of the diffusion regions are calculated self-consistently at each time step of the simulation using local MHD plasma and field parameters at the reconnection site without introduction of any ad hoc parameters. We d emonstrated that magnetotail reconnection is inherently unsteady even when the solar wind is steady. Global MHD simulations with nongyrotropic corrections produce bursts of fast reconnection typically observe d in small-scale kinetic simulations. During the bursts the length of the diffusion region does not exceed 2R(sub E) approximates 12(c/ome ga * pi). The bursts of the fast reconnection last only for a few min utes. After reaching the maximum value the reconnection rate decreases while the length of the diffusion region increases. The decreased ra te, however, is still significantly larger that the steady reconnection rate characteristic for MHD simulations with reconnection supported by numerical resistivity alone. Magnetotail reconnection supported b y nongyrotropic effects results in a tailward retreat of the reconnection site with average speed of the order of 100 km/s, accompanied by magnetotail stretching and thin current sheet formation in the near-E arth plasma sheet. Overall magnetotail response to the steady low-mach-number solar wind with southward IMF exhibits quasi-periodic loading /unloading dynamics typical for frequently observed multiple substorm s.
    Keywords: Geophysics
    Type: 2007 US-Japan Reconnection Workshop; 26-29 Mar. 2007; Saint Michaels, MD; United States
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    Chemistry Experiments (1999)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: The purpose of the chemistry component of the model comparison is to assess to what extent differences in the formulation of chemical processes explain the variance between model results. Observed concentrations of chemical compounds are used to estimate to what degree the various models represent realistic situations. For readability, the materials for the chemistry experiment are reported in three separate sections. This section discussed the data used to evaluate the models in their simulation of the source gases and the Nitrogen compounds (NO(y)) and Chlorine compounds (Cl(y)) species.
    Keywords: Geophysics
    Type: Models and Measurements Intercomparison 2; 190-306; NASA/TM-1999-209554
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  • 48
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    Backscatter Modeling at 2.1 Micron Wavelength for Space-Based and Airborne Lidars Using Aerosol Physico-Chemical and Lidar Datasets (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: Space-based and airborne coherent Doppler lidars designed for measuring global tropospheric wind profiles in cloud-free air rely on backscatter, beta from aerosols acting as passive wind tracers. Aerosol beta distribution in the vertical can vary over as much as 5-6 orders of magnitude. Thus, the design of a wave length-specific, space-borne or airborne lidar must account for the magnitude of 8 in the region or features of interest. The SPAce Readiness Coherent Lidar Experiment under development by the National Aeronautics and Space Administration (NASA) and scheduled for launch on the Space Shuttle in 2001, will demonstrate wind measurements from space using a solid-state 2 micrometer coherent Doppler lidar. Consequently, there is a critical need to understand variability of aerosol beta at 2.1 micrometers, to evaluate signal detection under varying aerosol loading conditions. Although few direct measurements of beta at 2.1 micrometers exist, extensive datasets, including climatologies in widely-separated locations, do exist for other wavelengths based on CO2 and Nd:YAG lidars. Datasets also exist for the associated microphysical and chemical properties. An example of a multi-parametric dataset is that of the NASA GLObal Backscatter Experiment (GLOBE) in 1990 in which aerosol chemistry and size distributions were measured concurrently with multi-wavelength lidar backscatter observations. More recently, continuous-wave (CW) lidar backscatter measurements at mid-infrared wavelengths have been made during the Multicenter Airborne Coherent Atmospheric Wind Sensor (MACAWS) experiment in 1995. Using Lorenz-Mie theory, these datasets have been used to develop a method to convert lidar backscatter to the 2.1 micrometer wavelength. This paper presents comparison of modeled backscatter at wavelengths for which backscatter measurements exist including converted beta (sub 2.1).
    Keywords: Geophysics
    Type: Tenth Biennial Coherent Laser Radar Technology and Applications Conference; 147-150; NASA/CP-1999-209758
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  • 49
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    Enhanced Fair-Weather Electric Fields Soon After Sunrise (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: The typical fair weather electric field at the ground is between -100 and -300 V/m. At the NASA Kennedy Space Center and US Air Force Cape Canaveral Air Station (KSC) the electric field at the ground sometimes reaches -400 to -1200 V/m within an hour or two after sunrise on days that otherwise seem to be fair weather. We refer to the enhanced negative electric fields as the "sunrise enhancement." To investigate the sunrise enhancement at KSC we measured the electric field (E) in the first few hundred meters above the ground before and during several sunrise enhancements. From these E soundings we can infer the presence of charge layers and determine their thickness and charge density.
    Keywords: Geophysics
    Type: 11th International Conference on Atmospheric Electricity; 583-586; NASA/CP-1999-209261
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    Electron density distribution in the magnetosphere (1997)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Eight months of differential potential measurements from the POLAR satellite were used to study the electron density distribution in the magnetosphere and its dependence on the level of geomagnetic activity identified by the Kp index. The differential potential measurement is directly proportional to the electron density, and this technique can be used for detecting fast electron density variation in low-density plasmas with a good accuracy. The inner magnetospheric regions are particularly investigated in this study. The cusp is found to be denser during low Km, and it moves equator-ward with increasing Km. The plasmapause is quite asymmetric, as expected. In particular, on the nightside, the plasmapause is compressed closer to the earth with increasing Kp. While the density gradients at the dayside plasmapause are usually not very steep, they can be quite large at other time sectors. A particularly pronounced sharpening of the plasmapause occurs at the dusk sector with increasing Kp. The density in the region between the dayside plasmapause and magnetopause is relatively high during all Kp levels; the average densities are several electrons per cubic meter. During disturbed periods, the density in the near-earth plasma sheet near midnight increases and becomes higher than the densities towards the flanks of the plasma sheet.
    Keywords: Geophysics
    Type: Proceedings of the 31st ESALB Symposium on Correlated Phenomena at the Sun, in the Heliosphere and in Geospace; 53-58; ESA-SP-415
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    LASE measurements of aerosols and water vapor during TARFOX (1998)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: The TARFOX (Tropospheric Aerosol Radiative Forcing Observational Experiment) intensive field campaign was designed to reduce uncertainties in estimates of the effects of anthropogenic aerosols on climate by measuring direct radiative effects and the optical, physical, and chemical properties of aerosols [1]. TARFOX was conducted off the East Coast of the United States between July 10-31, 1996. Ground, aircraft, and satellite-based sensors measured the sensitivity of radiative fields at various atmospheric levels to aerosol optical properties (i.e., optical thickness, phase function, single-scattering albedo) and to the vertical profile of aerosols. The LASE (Lidar Atmospheric Sensing Experiment) instrument, which was flown on the NASA ER-2 aircraft, measured vertical profiles of total scattering ratio and water vapor during a series of 9 flights. These profiles were used in real-time to help direct the other aircraft to the appropriate altitudes for intensive sampling of aerosol layers. We have subsequently used the LASE aerosol data to derive aerosol backscattering and extinction profiles. Using these aerosol extinction profiles, we derived estimates of aerosol optical thickness (AOT) and compared these with measurements of AOT from both ground and airborne sun photometers and derived from the ATSR-2 (Along Track and Scanning Radiometer 2) sensor on ERS-2 (European Remote Sensing Satellite-2). We also used the water vapor mixing ratio profiles measured simultaneously by LASE to derive precipitable water vapor and compare these to ground based measurements.
    Keywords: Geophysics
    Type: Nineteenth International Laser Radar Conference; 11-14; NASA/CP-1998-207671/PT1
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    Comparison of plasma probes in the lower ionosphere (1997)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: The instrumentation and the observations performed by four identically instrumented sounding rockets, designed to investigate the mesosphere and lower thermosphere, are reported. The four sounding rockets were launched from the Brazilian equatorial range Alcantara in August 1994. The instruments were capable of determining ion and electron densities. The results of data processing showed discrepancies hitherto unnoticed by other experiments.
    Keywords: Geophysics
    Type: ; 381-386
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    SIR-C Studies of the Precambrian Hamisana and Nakasib Structures, NE Sudan, in Arid Regions of Low Relief and in the Subsurface (1996)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: Progress, significant results, and future plans regarding the following project objectives are presented: (a) Develop techniques for optimizing structural analysis of basement trends in arid regions with extremely subdued topography and/or thin aeolian cover. b) Apply results of (a) to map the southern extension of the Hamisana Shear Zone and the western extension of Nakasib Suture. c) Apply results of (b) to constrain the roles of terrane accretion and strike-slip re-organization for late Precambrian crustal evolution in NE Africa.
    Keywords: Geophysics
    Type: Science Results from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR): Progress Report; 170-178; NASA/CR-97-206707
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    Development of a Technique to Relate Aeolian Roughness to Radar Backscatter using Multiparameter SIR-C Data (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Progress and future plans for the following objectives are presented: (1) To develop a technique to obtain values of aeolian roughness for geologic surfaces from values of surface roughness determined from calibrated L- and C-band, like- and cross-polarized, multiple incidence angle radar data from SIR-C; (2) To define the optimal combination of radar parameters from which aeolian roughness can be derived; and (3) To gain an understanding of the physical processes behind the empirical relationship.
    Keywords: Geophysics
    Type: Science Results from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR): Progress Report; 68-70; NASA/CR-97-206707
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    Detection of Polar Stratospheric Clouds Using AVHRR Imagery (1998)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: In recent years, the role of PSCs in the ozone depletion process has become better understood. PSCs provide the surfaces upon which heterogeneous reactions take place that affect the gas phase partitioning between active and reservoir chlorine and nitrogen species. Present methods of PSC detection include in situ measurements by lidar and various satellite-borne instruments such as the Stratospheric Aerosol Measurement II (SAM II) on the Nimbus 7 spacecraft, which produced PSC measurements from 1978 to 1994 and several instruments onboard the Upper Atmospheric Research Satellite (UARS) such as the Cryogenic Limb Array Etalon Spectrometer (CLAES) which provided measurements for 1991-1993. All of the PSC-detection methods devised so far have been hampered by incomplete sampling of the places and times in which PSCs are likely to form. There is a need to understand the climatology of PSCS, in particular the timing of their onset and duration, their vertical distribution, geographic extent, annual variability and responses to volcanic aerosol forcing. Poole and Pitts [1994] assembled a PSC climatology based on SAM II data, but this climatology is incomplete, as it is limited to the edge of the polar night due to the limitations of the solar occultation scan geometry. The Advanced Very High Resolution Radiometer (AVHRR) five- channel sensors onboard the NOAA polar-orbiting satellites have been collecting data over the polar regions continuously since 1979. These operational satellites provide unmatched coverage in space and time of both polar regions, but were not designed for the detection of optically-thin PSCS. However, the AVHRR data archive would be an invaluable source for the construction of a long-term climatology of PSCs if techniques can be developed and tested to detect PSCs in AVHRR data. In the last few years, the members of our group at San Francisco State University and NASA Ames Research Center have been engaged in the development of various PSC detection methods using AVHRR data. There is strong evidence that a subset of PSCS, those that are optically thick, can be readily identified in the AVHRR data set. Our group has also made significant progress in the identification of optically thinner PSCs using a variety of techniques.
    Keywords: Geophysics
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    Validation of Saharan Dust Layer Characteristics with Lidar Observations (1998)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: Lidar backscattering profiles available from the LITE data set have been used to estimate the optical depths of the Saharan dust layer over West Africa and E. Atlantic regions, in the context of validating the 3-D conceptual model of the Saharan dust plume proposed by Karyampudi and Carlson. The aerosol extinction profiles and optical depths were retrieved from LITE using the Fernald et al. (1972) method. An extinction-to-backscattering ratio, S(sub a), of 25 was selected for optical depth calculations. The spatial analysis of total column and Saharan dust layer optical depths show higher optical depths over W. Africa that decrease westward over E. Atlantic. The higher optical depths over W. Africa, in general, are associated with heavy dust being raised from the surface in dust source regions. Rapid depletion of these heavy dust particles, perhaps due to sedimentation, appear to decrease the dust loading within the dust layer as the plume leaves the west African continent. Higher optical depths are generally confined to the southern edge of the dust layer, where the middle level jet appears to transport the heavy dust concentrations that tend to mix downward from vertical mixing associated with the strong vertical shears underneath the middle jet. Thus, LITE measurements although, in general, validate the Saharan dust plume conceptual model, show maximum values of optical depths near the southern edge of the dust plume over the E. Atlantic region instead of near the center of the dust plume as described in the conceptual model.
    Keywords: Geophysics
    Type: Nineteenth International Laser Radar Conference; Part 2; 685-690; NASA/CP-1998-207671/PT2
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    Layering in halocarbons, methane, nitrous oxide, ozone, and water vapour over mid-latitudes (1997)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: The purpose of the balloon flights performed in March 1993 from Aire-sur-Adour (France) was to measure trace gases in the polar vortex during a dynamically active period. These balloon flights revealed coincident layering in long-lived tropospheric source gases. A layer of mid-latitude air, enriched in trace gases, was detected at sampled levels near 15 mbar. High resolution advection models, fine scale distributions of ozone, nitrous oxide, methane, and halocarbons were constructed. The calculations showed how air enriched in trace gases is sampled near 15 mbar when a filament of such air is drawn into the outer portion of the vortex.
    Keywords: Geophysics
    Type: ; 187-192
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    Towards quantifying mesoscale flows in the troposphere using Raman lidar and Sondes (1998)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Water vapor plays an important role in the energetics of the boundary layer processes which in turn play a key role in regulating regional and global climate. It plays a primary role in Earth's hydrological cycle, in radiation balance as a direct absorber of infrared radiation, and in atmospheric circulation as a latent heat energy source, as well as in determining cloud development and atmospheric stability. Water vapor concentration, expressed as a mass mixing ratio (g kg(exp -l)), is conserved in all meteorological processes except condensation and evaporation. This property makes it an ideal choice for studying many of the atmosphere's dynamic features. Raman scattering measurements from lidar also allow retrieval of water vapor mixing ratio profiles at high temporal and vertical resolution. Raman lidars sense water vapor to altitudes not achievable with towers and surface systems, sample the atmosphere at much higher temporal resolution than radiosondes or satellites, and do not require strong vertical gradients or turbulent fluctuations in temperature that is required by acoustic sounders and radars. Analysis of highly-resolved water vapor profiles are used here to characterize two important mesoscale flows: thunderstorm outflows and a cold front passage. The data were obtained at the Atmospheric Radiation Measurement Site (CART) by the groundbased Department of Energy/Sandia National Laboratories lidar (CART Raman lidar or CARL) and Goddard Space Flight Center Scanning Raman Lidar (SRL). A detailed discussion of the SRL and CARL performance during the IOPs is given by others in this meeting.
    Keywords: Geophysics
    Type: Nineteenth International Laser Radar Conference; 403-406; NASA/CP-1998-207671/PT1
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    Chemistry and dynamics of the lower troposphere over North America and the North Atlantic Ocean in fall 1997 observed using an airborne UV DIAL system (1998)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: The NASA Langley Research Center's airborne UV Differential Absorption Lidar (DIAL) system participated in the Subsonic Assessment, Ozone and Nitrogen Oxide Experiment (SONEX) mission from October 13 to November 12, 1997. The purpose of the mission was to study the upper troposphere/lower stratosphere in and near the North Atlantic flight corridor to better understand this region of the atmosphere and how civilian air travel in the corridor might be affecting the atmospheric chemistry. Bases of operations included NASA Ames, California (37.4 deg N, 122.1 deg W); Bangor, Maine (44.8 deg N, 68.8 deg W); Shannon, Ireland (52.7 deg N, 8.9 deg W); and Lajes, Terceira Island, Azores (38.8 deg N, 27.1 deg W). Since the UV DIAL system observes in the nadir as well as the zenith, aerosol and ozone data were obtained from near the Earth's surface to the lower stratosphere. A number of interesting features were noted relating to both chemistry and dynamics of the troposphere, which are reported here.
    Keywords: Geophysics
    Type: Nineteenth International Laser Radar Conference; 379-381; NASA/CP-1998-207671/PT1
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    Results of the NY-Alesund ozone measurements intercomparison NAOMI (1998)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Worldwide, about ten Differential Absorption Lidars are used for long-term monitoring of stratospheric ozone. These systems are an important component of the Network for the Detection of Stratospheric Change. Although DIALs are self-calibrating in principle, regular intercomparisons with other ozone-lidars, microwave radiometers or ozone-sondes are highly desirable to ensure high data quality at a well known level. The Network for the Detection of Stratospheric Change (NDSC) validation policy suggests that such intercomparisons be "blind", meaning all participants submit their data to an impartial referee, without seeing results from the other participants. Here we report on the "blind" intercomparison taking place from January 20th to February 10th 1998 at Ny-Alesund, Spitsbergen (78.92 deg N, 11.95 deg E). Participating groups were from the Alfred Wegener Institute, Potsdam, operating the NDSC DIAL system at Ny-Alesund, from the University of Bremen operating the NDSC microwave radiometer for ozone profiling at Ny-Alesund, and the NASA Goddard Space Flight Center group with the "NDSC travelling standard" STROZ-LITE. The first author acted as the impartial referee. Also used for the intercomparison were data from ECC-6A/Vaisala RS80 ozone sondes routinely launched at Ny-Alesund by the AWI group. A 1% KI solution (3 ml) and the 1986 ECC pump correction (1.092 at 5 hPa) are used. The ECC-data were available to all participants during the campaign and thus were not "blind". Table 1 summarizes the expected performance of the instruments participating in the ozone intercomparison reported in this paper.
    Keywords: Geophysics
    Type: Nineteenth International Laser Radar Conference; 347-350; NASA/CP-1998-207671/PT1
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    Perspectives of the 1st IACG Campaign: Preliminary Results (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: The activities and aims of the Inter-Agency Consultative Group (IACG) for space science are reported on. The principle aim is to enhance the scientific return among the members through the coordination of their fleets of current and future spacecraft. The four current campaigns are: magnetotail energy flow and nonlinear dynamics; boundaries in the collisionless plasma; solar events and their manifestations in interplanetary space and geoscience, and solar sources of heliospheric structure observed out of the ecliptic. The first of these campaigns and its implementation are reviewed.
    Keywords: Geophysics
    Type: Third International Conference on Substorms (ICS-3); 707-711; ESA-SP-389
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    Traveling compression region observed in the mid-tail lobes near substorm expansion phase onset (1996)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: The characteristics of traveling compression regions (TCRs) in the midtail lobes are examined. Through the use of the AL index, isolated substorm events with well developed expansion phases are selected. The TCR events which feature a field compression coincident with modified Bz variations are categorized into different types, and the magnetic variations are interpreted in terms of the relative location of the point of observation to the plasmoid at the time of release and the effects of tail flaring. In order to understand the relationship between the plasmoid release time and the substorm onset time, the time difference between the different types of TCR and the substorm onset determined by Pi 2 pulsations at mid-latitude ground stations, is examined. The results suggest that the downtail release of most of the plasmoids created earthwards of -38 earth radii occurs at almost the same distance as the substorm onset.
    Keywords: Geophysics
    Type: ; 603-607
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    Global Geospace Science (GGS) Program and the Polar Satellite (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: The Global Geospace Science (GGS) program's Polar satellite is reported on. The satellite aims to measure: the plasma flux in the polar magnetosphere and the geomagnetic tail; the plasma flux to and from the ionosphere, and the deposition of particle energy in the upper atmosphere. To accomplish these objectives, the satellite was placed on a 86 deg inclination, elliptical orbit whose apogee is located over the northern polar region. The spacecraft carries instruments for observing and measuring the magnetic field and charged particles as well as the imaging instruments.
    Keywords: Geophysics
    Type: Third International Conference on Substorms (ICS-3); 721-724; ESA-SP-389
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    Special Diagnostics (1999)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: This section contains a number of special diagnostics that are designed to examine certain mechanisms. Section 1 reports on the method used to test the photochemical partitioning in the models. Sections 2 and 3 represent efforts to examine the model calculated production and removal rates for ozone and how the values are combined with transport rates in the models to produce the simulated ozone distributions. Sections 4 and 5 concentrate on polar processes including the dynamics aspect of vortex confinement and the chemical aspects of chlorine activation.
    Keywords: Geophysics
    Type: Models and Measurements Intercomparison 2; 363-448; NASA/TM-1999-209554
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    Transport Experiments (1999)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: MM II defined a series of experiments to better understand and characterize model transport and to assess the realism of this transport by comparison to observations. Measurements from aircraft, balloon, and satellite, not yet available at the time of MM I [Prather and Remsberg, 1993], provide new and stringent constraints on model transport, and address the limits of our transport modeling abilities. Simulations of the idealized tracers the age spectrum, and propagating boundary conditions, and conserved HSCT-like emissions probe the relative roles of different model transport mechanisms, while simulations of SF6 and C02 make the connection to observations. Some of the tracers are related, and transport diagnostics such as the mean age can be derived from more than one of the experiments for comparison to observations. The goals of the transport experiments are: (1) To isolate the effects of transport in models from other processes; (2) To assess model transport for realistic tracers (such as SF6 and C02) for comparison to observations; (3) To use certain idealized tracers to isolate model mechanisms and relationships to atmospheric chemical perturbations; (4) To identify strengths and weaknesses of the treatment of transport processes in the models; (5) To relate evaluated shortcomings to aspects of model formulation. The following section are included:Executive Summary, Introduction, Age Spectrum, Observation, Tropical Transport in Models, Global Mean Age in Models, Source-Transport Covariance, HSCT "ANOY" Tracer Distributions, and Summary and Conclusions.
    Keywords: Geophysics
    Type: Models and Measurements Intercomparison 2; 110-189; NASA/TM-1999-209554
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    Simulation of the Universal-Time Diurnal Variation of the Global Electric Circuit Charging Rate (1999)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: A global lightning model that includes diurnal and annual lightning variation, and total flash density versus latitude for each major land and ocean, has been used as the basis for simulating the global electric circuit charging rate. A particular objective has been to reconcile the difference in amplitude ratios [AR=(max-min)/mean] between global lightning diurnal variation (AR approx. = 0.8) and the diurnal variation of typical atmospheric potential gradient curves (AR approx. = 0.35). A constraint on the simulation is that the annual mean charging current should be about 1000 A. The global lightning model shows that negative ground flashes can contribute, at most, about 10-15% of the required current. For the purpose of the charging rate simulation, it was assumed that each ground flash contributes 5 C to the charging process. It was necessary to assume that all electrified clouds contribute to charging by means other than lightning, that the total flash rate can serve as an indirect indicator of the rate of charge transfer, and that oceanic electrified clouds contribute to charging even though they are relatively inefficient in producing lightning. It was also found necessary to add a diurnally invariant charging current component. By trial and error it was found that charging rate diurnal variation curves in Universal time (UT) could be produced with amplitude ratios and general shapes similar to those of the potential gradient diurnal variation curves measured over ocean and arctic regions during voyages of the Carnegie Institute research vessels.
    Keywords: Geophysics
    Type: 11th International Conference on Atmospheric Electricity; 634-637; NASA/CP-1999-209261
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    Gravitational Wave Search with the Clock Mission (1997)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Doppler tracking of distant spacecraft is the only method currently available to search for gravitational waves in the low-frequency (approx. 0.0001-0.1 Hz) band. In this technique the Doppler system measures the relative dimensionless velocity 2(delta)v/c = (delta)f/f(sub o) between the earth and the spacecraft as a function of time, where (delta)f is the frequency perturbation and f(sub o) is the nominal frequency of the radio link. A gravitational wave of amplitude h incident on this system causes small frequency perturbations, of order h in (delta)f/f(sub o), replicated three times in the observed record (Estabrook and Wahlquist 1975). All experiments to date and those planned for the near future involve only 'two-way' Doppler-i.e., uplink signal coherently transponded by the spacecraft with Doppler measured using a frequency standard common to the transmit and receive chains of the ground station. If, as on the proposed Clock Mission, there is an additional frequency standard on the spacecraft and a suitable earth-spacecraft radio system, some noise sources can be isolated and removed from the data (Vessot and Levine 1978). Supposing that the Clock Mission spacecraft is transferred into a suitable interplanetary orbit, I discuss here how the on-board frequency standard could be employed with an all-Ka-band radio system using the very high stability Deep Space Network station DSS 25 being instrumented for Cassini. With this configuration, the Clock Mission could search for gravitational waves at a sensitivity limited by the frequency standards, rather than plasma or tropospheric scintillation effects, whenever the sun-earth-spacecraft angle is greater than 90 degrees.
    Keywords: Geophysics
    Type: Proceedings of the Workshop on the Scientific Applications of Clocks in Space; 33-40; NASA/CR-97-112594
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    Ionospheric convection during different phases of magnetospheric substorms (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Observations of ionospheric convection flows at a range of local times during the various phases of the substorm cycle are reported on with the aim of investigating the convection behavior during a range of times and phases. The ionospheric flow observations are from the EISCAT and DMSP satellites. The substorm phases are identified from energetic particle measurements from geosynchronous satellites. The growth phase convection indicates an initial expansion of the polar cap. There is an unexplained poleward motion of the flow reversal boundary (FRB). It is concluded that this motion does not necessarily provide a true representation of the balance between reconnection at the dayside and in the tail. The expansion phase flows do not show any evidence for tail reconnection until late in the phase. The convection during the recovery phase is indicative of tail reconnection as there is evidence that there is only a lobe cell driving convection on the dayside.
    Keywords: Geophysics
    Type: ; 103-108
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    GOME Calibration and Validation Using Backscatter UV Techniques (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: GOME radiance, irradiance, and ozone products were validated by NASA Goddard Space Flight Center through three tasks which included, pre-launch calibration comparisons with SBUV and TOMS radiometric standards, validation of GOME Level-1 irradiance and radiance and Level 2 total ozone data products using SBUV/2 and TOMS algorithms and data, and studies of GOME data using the Goddard radiative transfer code. The prelaunch calibration using the NASA large aperture integrating sphere was checked against that provided by TPD. Agreement in the calibration constants, derived in air, between the Goddard and TPD system were better than 3%. Validation of Level-1 irradiance data included comparison of GOME and SSBUV and the UARS solar irradiances measurements. Large wavelength dependent differences, as high as 10%, were noted between GOME and the US instruments. This discrepancy has now been attributed to radiometric sensitivity changes experienced by GOME when operating in a vacuum. GOME Earth radiance data were then compared to the NOAA-14 SBUV/2 radiances. These results show that between 340 and 400 nm the differences in GOME and SBUV/2 data are less than 5% with some wavelength dependence. At wavelengths shorter than 300 nm, differences are of the order of 10% or more where the GOME radiances are larger. To test GOME DOAS retrieved total ozone values, these values were compared with ozone amounts retrieved using GOME radiances in the TOMS version-7 algorithm. The differences showed a solar zenith angle dependence ranging from 0 to 10% where the TOMS algorithm values were higher. GOME radiances below 300 nm were further validated by selecting radiances at wavelengths normally used by SBUV and processing them through the SBUV ozone profile algorithm and then compared to climatological values. The GOME ozone profiles ranged from 10-30% lower over altitude compared to climatological values. This is consistent with the offsets detected in the SBUV/2 radiance comparisons at wavelengths shorter than 300 nm.
    Keywords: Geophysics
    Type: US Participation in the GOME and SCIAMACHY Projects; 85-91; NASA-CR-202573
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    Study of the rotational-level and temperature dependence of the quenching rate of OH fluorescence due to collisions with water molecules (1995)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: The importance of the OH radical as an intermediate in many combustion reactions and in atmospheric photochemistry has led many researchers to use it as a diagnostic tool in these processes. The amount of data that has been acquired over the years for this radical is quite considerable. However, the quenching rate of OH with water molecules as a function of temperature and the rotational level of the excited state is not very well understood. The motivation of the studies undertaken is to bridge the gap between the low temperature measurements and the high temperature ones reported in the literature. The technique generally employed in these diagnostics is laser-induced fluorescence (LIF), through which rotational state selective excitation of the radical is possible. Furthermore, in a combustion medium, water is produced in abundance so that knowledge of the quenching rate of OH due to water molecules plays a crucial role in interpreting the data. In general, the precursor to an understanding of the collisional quenching rates of OH involves a characterization of the mode in which the radical is produced; the resulting rotational and translational distribution, followed by a measurement of the OH temperature; and ultimately obtaining the rate constants from the pressure dependence of the fluorescence signal. The experimental implementation of these measurements therefore involved, as a first step, the production of the OH radicals in a microwave discharge cell using water vapor as the source, wherein a hydrogen atom is abstracted from H2O. The second step involved the absorption of photons from the frequency-doubled output of a pulsed amplified, single-frequency cw ring dye laser. By tuning the laser to the peak of the transition and observing the fluorescence decay after the laser pulse, the lifetime of the OH in a particular rotational electronic state was determined (tau = 1.4 microseconds for Q(sub 1)(3)). Knowledge of this parameter led to a determination of the quenching rate. By varying the water vapor pressure in the cell and measuring the lifetime as a function of pressure a linear plot of the quenching rate as a function of pressure was obtained. Using this plot, the quenching cross section was deduced. It has therefore been possible to measure the local translational temperature and the quenching cross section with one laser system.
    Keywords: Geophysics
    Type: The 1995 NASA-ODU American Society for Engineering Education (ASEE) Summer Faculty Fellowship Program; 86-87; NASA-CR-198210
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    Textural and Carbon Isotopic Analyses of Modern Carbonate Microbialites: Possible Ancient and Martian Analogs (1998)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Many modem and ancient carbonate deposits around the world have been recognized as microbial buildups or microbialites. Ancient microbialite structures have been divided into two basic categories based on their internal fabric or texture. They include stromatolites which have a predominantly laminated internal fabric and thrombolites which have an open-porous clotted fabric, that lacks laminae. The origin of these two basic microbial fabrics is still being debated in the literature. Understanding the origin and the various microorganisms involved in forming these modem fabrics is the key to the interpretation of similar fabrics in ancient and possibly Martian rocks. Therefore, detailed studies are needed on the microbiological makeup and origin of the fabrics in modem microbialites. Such studies may serve as analogs for ancient and Martian microbialites in the future. The purpose of this study is to examine the textures and carbon isotopic signatures of the following modem microbialites from the Bahamas: 1) a modem subtidal microbialite from Iguana Cay, Bahamas and 2) a modem microbial mat (stromatolite) from a hypersaline pond on Lee Stocking Island, Bahamas.
    Keywords: Geophysics
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    Lidar Measurements of Tropospheric Wind Profiles with the Double Edge Technique (1998)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Research has established the importance of global tropospheric wind measurements for large scale improvements in numerical weather prediction. In addition, global wind measurements provide data that are fundamental to the understanding and prediction of global climate change. These tasks are closely linked with the goals of the NASA Earth Science Enterprise and Global Climate Change programs. NASA Goddard has been actively involved in the development of direct detection Doppler lidar methods and technologies to meet the wind observing needs of the atmospheric science community. A variety of direct detection Doppler wind lidar measurements have recently been reported indicating the growing interest in this area. Our program at Goddard has concentrated on the development of the edge technique for lidar wind measurements. Implementations of the edge technique using either the aerosol or molecular backscatter for the Doppler wind measurement have been described. The basic principles have been verified in lab and atmospheric lidar wind experiments. The lidar measurements were obtained with an aerosol edge technique lidar operating at 1064 nm. These measurements demonstrated high spatial resolution (22 m) and high velocity sensitivity (rms variances of 0.1 m/s) in the planetary boundary layer (PBL). The aerosol backscatter is typically high in the PBL and the effects of the molecular backscatter can often be neglected. However, as was discussed in the original edge technique paper, the molecular contribution to the signal is significant above the boundary layer and a correction for the effects of molecular backscatter is required to make wind measurements. In addition, the molecular signal is a dominant source of noise in regions where the molecular to aerosol ratio is large since the energy monitor channel used in the single edge technique measures the sum of the aerosol and molecular signals. To extend the operation of the edge technique into the free troposphere we have developed a variation of the edge technique called the double edge technique. In this paper a ground based aerosol double edge lidar is described and the first measurements of wind profiles in the free troposphere obtained with this lidar will be presented.
    Keywords: Geophysics
    Type: Nineteenth International Laser Radar Conference; Part 2; 587-590; NASA/CP-1998-207671/PT2
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    Application of magnetospheric imaging techniques to global substorm dynamics (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: The application of remote sensing techniques to the analysis of the dynamics of storms and substorm processes is discussed. The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission, its mission and instruments are presented. The following are discussed: neutral atom imaging; radio plasma techniques; photon imaging, and substorm observations.
    Keywords: Geophysics
    Type: ; 655-661
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    Estimates of magnetic flux, and energy balance in the plasma sheet during substorm expansion (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: The energy and magnetic flux budgets of the magnetotail plasma sheet during substorm expansion are investigated. The possible mechanisms that change the energy content of the closed field line region which contains all the major dissipation mechanisms of relevance during substorms, are considered. The compression of the plasma sheet mechanism and the diffusion mechanism are considered and excluded. It is concluded that the magnetic reconnection mechanism can accomplish the required transport. Data-based empirical magnetic field models are used to investigate the magnetic flux transport required to account for the observed magnetic field dipolarizations in the inner magnetosphere. It is found that the magnetic flux permeating the current sheet is typically insufficient to supply the required magnetic flux. It is concluded that no major substorm-type magnetospheric reconfiguration is possible in the absence of magnetic reconnection.
    Keywords: Geophysics
    Type: ; 549-554
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    Hybrid modeling of the formation and structure of thin current sheets in the magnetotail (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Hybrid simulations are used to investigate the formation of a thin current sheet inside the plasma sheet of a magnetotail-like configuration. The initial equilibrium is subjected to a driving electric field which is qualitatively similar to what would be expected from solar wind driving. As a result, a new current sheet with the thickness of approximately the ion inertial length is formed. The current density inside the current sheet region is supplied largely by the electrons. Ion acceleration in the cross-tail direction is absent as the driving electric field fails to penetrate into the equatorial region.
    Keywords: Geophysics
    Type: ; 231-236
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    Substorm associated ion acceleration in the dynamic magnetotail (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: Ion acceleration and flux increase associated with substorm energetic particle injections are investigated on the basis of geosynchronous observations and test proton orbits in the dynamic fields of a three dimensional magnetohydrodynamic simulation of neutral line formation and dipolarization in the magnetotail. The energetic particle flux changes obtained from the test particle orbits agree well with observations that demonstrate rapid ion flux increases at energies of above 20 keV. The injection region inferred from the test particles has a sharp earthward boundary and a sharp ragged tailward boundary. The earthward portion of the enhanced ion flux can be traced to the enhanced cross-tail electric field associated with the near-earth x-type neutral line. Due to the rapid earthward motion of accelerated ions away from the neutral line, this boundary is displaced earthward to where the energetic ions become more adiabatic in the stronger dipolar field.
    Keywords: Geophysics
    Type: ; 243-248
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    Line Coupling in Atmospheric Spectra (1996)
    In:  CASI
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    Publication Date: 2004-12-03
    Description: The theoretical modeling of atmospheric spectra is important for a number of different applications: for instance, in the determination of minor atmospheric constituents such as ozone, carbon dioxide, CFC's etc.; in monitoring the temperature profile for climate studies; and in measuring the incoming and outgoing radiation to input into global climate models. In order to accomplish the above mentioned goal, one needs to know the spectral parameters characterizing the individual spectral lines (frequency, width, strength, and shape) as well as the physical parameters of the atmosphere (temperature, abundances, and pressure). When all these parameters are known, it is usually assumed that the resultant spectra and concomitant absorption coefficient can then be calculated by a superposition of individual profiles of appropriate frequency, strength and shape. However, this is not true if the lines are 'coupled'. Line coupling is a subtle effect that takes place when lines of a particular molecule overlap in frequency. In this case when the initial states and the final states of two transitions are connected by collisions, there is a quantum interference resulting in perturbed shapes. In general, this results in the narrowing of Q-branches (those in which the rotational quantum number does not change), and vibration-rotational R- and P branches (those in which the rotational quantum number changes by +/- 1), and in the spectral region beyond band heads (regions where the spectral lines pile up due to centrifugal distortion). Because these features and spectral regions are often those of interest in the determination of the abundances and pressure-temperature profiles, one must take this effect into account in atmospheric models.
    Keywords: Geophysics
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    Salt Kinematics and InSAR (2005)
    In:  CASI
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    Publication Date: 2005-04-25
    Description: As part of a long-term attempt to learn how the climatic and tectonic signal interact to shape a steady state mountain monitored displacement of a markers in SE termination and also near the summit of a small viscous salt fountain extruding onto the Central plateau of Iran. The marker displacements relate to the first InSAR interferograms of salt extrusion (980913 to 990620) calculated Earth tides, winds, air pressures and temperatures. In the first documented staking exercise, hammered wooden stakes vertically through the surgical marl (c. 1 Ocm deep) onto the top of crystalline salt. These stakes installed in an irregular array elongate E-W along the c.50 m high cliff marking the effective SE terminus of the glacier at Qum Kuh(Centra1 Iran) ,just to the E of a NE trending river cliff about 40 m high. We merely measured the distances between pairs of stakes with known azimuth about 2 m apart to calculate sub horizontal strain in a small part of Qum Kuh. Stakes moved and micro strains for up to 46 pairs of stakes (p strain= ((lengthl-length2)/1engthl) x 10-1) was calculated for each seven stake epochs and plotted against their azimuth on simplified array maps. The data fit well the sine curves cxpected of the maximum and minimum strain ellipses. The first documented stakes located on the SE where the InSAR image show -1 1 to 0 mm pink to purple, 0 to lOmm purple to blue, and show high activity of salt in low activity area of the InSAR image (980913 to 990620).Short term micro strains of stake tie lines record anisotropic expansions due to heating and contraction due to cooling. All epochs changed between 7 to 1 17 days (990928 to000 1 16), showed 200 to 400 micro strain lengthening and shortening. The contraction and extension existed in each epoch, but the final strain was extension in E-W in Epoch land 6, contraction in E-W direction during epochs 2-3-4-5 and 7. The second pair of stakes hammered about 20 cm deep into the deep soils(more than 1 m) , near summit, where the colors change between 19 to 29mm in InSAR image(9809 13 to 990620). Additional information is included in the original abstract.
    Keywords: Geophysics
    Type: Workshop on Radar Investigations of Planetary and Terrestrial Environments; 17; LPI-Contrib-1231
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    Teaching Soil Science in Primary and Secondary Schools (1998)
    In:  CASI
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    Publication Date: 2009-05-03
    Description: Earth's thin layer of soil is a fragile resource, made up of minerals, organic materials, air, water, and billions of living organisms. Soils plays a variety of critical roles that sustain life on Earth. If we think about soil, we tend to see it first as the source of most of the food we eat and the fibers we use, such as wood and cotton. Few students realize that soils also provide the key ingredients to many of the medicines (including antibiotics), cosmetics, and dyes that we use. Fewer still understand the importance of soils in integrating, controlling, and regulating the movement of air, water, materials, and energy between the hydrosphere, lithosphere, atmosphere, and biosphere. Because soil sustains life, it offers both a context and a natural laboratory for investigating these interactions. The enclosed poster, which integrates soil profiles with typical landscapes in which soils form, can also help students explore the interrelationships of Earth systems and gain an understanding of our soil resources. The poster, produced jointly by the American Geological Institute and the Soil Science Society of America, aims to increase awareness of the importance of soil, as does the GLOBE (Global Learning and Observations To Benefit the Environment) Program. Vice President Al Gore instituted the GLOBE Program on Earth Day of 1993 to increase environmental awareness of individuals throughout the world, contribute to a better scientific understanding of the Earth, and help all students reach higher levels of achievement in science and mathematics. GLOBE functions as a partnership between scientists, students, and teachers in which scientists design protocols for specific measurements they need for their research that can be performed by K-12 students. Teachers are trained in the GLOBE protocols and teach them to their students. Students make the measurements, enter data via the Internet to a central data archive, and the data becomes available to scientists and the general community. Students benefit by having a "hands-on"experience in science, math, and technology, using their local environment as a learning laboratory, as well as contact with scientists and other students around the world. Soil investigations have become an essential component of GLOBE. The protocols that have been developed so far within the GLOBE program include GPS Location, Atmosphere/Climate, Soil Characterization, Soil Moisture and Temperature, Land Cover/Biometry, Hydrology, and Satellite Image Classification. For the GLOBE Soil Characterization Protocol, students explore the physical. chemical, and morphological properties of the soil at their study site. They are asked to dig a pit or use an auger to about 1 meter at at least 2 sites.
    Keywords: Geophysics
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    Formaldehyde Distribution over North America: Implications for Satellite Retrievals of Formaldehyde Columns and Isoprene Emission (2006)
    In:  Other Sources
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    Publication Date: 2011-08-26
    Description: Formaldehyde (HCHO) columns measured from space provide constraints on emissions of volatile organic compounds (VOCs). Quantitative interpretation requires characterization of errors in HCHO column retrievals and relating these columns to VOC emissions. Retrieval error is mainly in the air mass factor (AMF) which relates fitted backscattered radiances to vertical columns and requires external information on HCHO, aerosols, and clouds. Here we use aircraft data collected over North America and the Atlantic to determine the local relationships between HCHO columns and VOC emissions, calculate AMFs for HCHO retrievals, assess the errors in deriving AMFs with a chemical transport model (GEOS-Chem), and draw conclusions regarding space-based mapping of VOC emissions. We show that isoprene drives observed HCHO column variability over North America; HCHO column data from space can thus be used effectively as a proxy for isoprene emission. From observed HCHO and isoprene profiles we find an HCHO molar yield from isoprene oxidation of 1.6 +/- 0.5, consistent with current chemical mechanisms. Clouds are the primary error source in the AMF calculation; errors in the HCHO vertical profile and aerosols have comparatively little effect. The mean bias and 1Q uncertainty in the GEOS-Chem AMF calculation increase from 〈1% and 15% for clear skies to 17% and 24% for half-cloudy scenes. With fitting errors, this gives an overall 1 Q error in HCHO satellite measurements of 25-31%. Retrieval errors, combined with uncertainties in the HCHO yield from isoprene oxidation, result in a 40% (1sigma) error in inferring isoprene emissions from HCHO satellite measurements.
    Keywords: Geophysics
    Type: Journal of Geophysical Research; Volume 111
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    Remote sensing measurements of atmospheric methane at 2.3 microns with a nonmechanical GFCR (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Gas filter correlation radiometer (GFCR) is a passive remote sensing technique used in a variety of atmospheric measurements. In recent years, a nonmechanical optical switching GFCR has been invented and developed at NASA Langley Research Center. The use of a polarization modulator, in conjunction with a polarization beamsplitter, enables rapid optical switching without mechanically moving parts. In comparison with the conventional GFCR, which involves mechanical chopping or switching between two optical paths, the nonmechanical GFCR possesses some very attractive advantages such as fast sampling rate, high reliability, low weight, and long operational life time. In a recent study, we have developed a new GFCR configuration and have fabricated a compact, nonmechanical breadboard instrument. Using this instrument, we have carried out atmospheric methane measurements in the 2.3 micron region. Measurement results are compared with theoretical predictions using the HITRAN database.
    Keywords: Geophysics
    Type: Optical Remote Sensing of the Atmosphere, Volume 2; 224-226; LC-95-67220
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    Global tropospheric and total ozone monitoring with a Double-Etalon Fabry-Perot interferometer (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Knowledge of the global scale distribution of atmospheric ozone and its temporal variability can be achieved using a satellite-based nadir-viewing device making high spectral resolution measurements with high signal-to-noise ratios. This would enable observation in the pressure-broadened wings of strong O3 lines while minimizing the impact of undesirable signal contributions associated with, for example, the terrestrial surface and interfering species. The Fabry-Perot interferometer (FPI) provides high spectral resolution and high throughput capabilities that are essential for this measurement task. The periodic nature of the Fabry-Perot instrument function can be advantageous when observation of periodic spectra is desired. However, for most applications, additional optical elements are necessary to reduce the effect of unwanted passbands. This is frequently accomplished using additional Fabry-Perot etalons in a series configuration in conjunction with a bandpass filter. This paper discusses a Fabry-Perot interferometer conceptual instrument design to achieve tropospheric and total ozone monitoring capability from a satellite-based nadir-viewing geometry. The design involves a double-etalon fixed-gap series configuration FPI along with an ultra-narrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately .068 cm(exp -1). The impact of inter-etalon reflections has been reduced to acceptable levels by placement of a slightly attenuating medium in between the etalons. A passive device is selected for low power consumption, and continuous day/night coverage, independent of solar zenith angle, is enabled by observing within the strong 9.6 micron ozone infrared band. The IR-FPI detection will be performed through implementation of the new Circle to Line Interferometer Optical (CLIO) system, developed by researchers at the Space Physics Research Laboratory (SPRL) of the University of Michigan, to accomplish focal plane fringe detection; the CLIO system converts the circular interferometric fringes into a linear pattern which then can be detected by conventional linear array detectors. A multiplex signal advantage is achievable as all necessary frequencies can be measured simultaneously using a multichannel configuration. Through proper selection of channel spectral regions, the FPI optimized for tropospheric O3 measurements can simultaneously observe a stratospheric component and thus the total O3 column abundance.
    Keywords: Geophysics
    Type: Optical Remote Sensing of the Atmosphere, Volume 2; 199-202; LC-95-67220
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    Ozone vertical distribution retrieval from ground-based high resolution infrared solar spectra (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: A practical procedure for the retrieval of ozone vertical profiles from ground-based high resolution Fourier transform infrared solar spectra has been developed. The analysis is based on a multilayer line-by-line forward model and a semi-empirical version of the optimal estimation inversion method of Rodgers. The 1002.6-1003.2 cm(exp -1) spectral interval has been selected for the analysis on the basis of synthetic spectrum calculations. This interval contains numerous ozone lines covering a range of intensities and providing retrieval sensitivity from ground level to about 35 km. Characterization of the method and an error analysis have been performed. For a spectral resolution of 0.05-0.01 cm(exp -1) and a signal-to-noise ratio greater than or equal to 100 the retrieval is stable with a vertical resolution of approximately 5 km attainable near the surface degrading to approximately 10 km in the stratosphere. Synthetic spectra studies show that the a priori profile and weak constraints selected for the retrievals introduce no significant biases for a wide range of ozone profiles.
    Keywords: Geophysics
    Type: Optical Remote Sensing of the Atmosphere, Volume 2; 193-194; LC-95-67220
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    Atmospheric Multiple Scattering Effects on GLAS Altimetry (1999)
    In:  Other Sources
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    Publication Date: 2011-08-23
    Description: Estimates of the effect of pulse stretching on satellite laser altimetry in particular the Geoscience Laser Altimeter System (GLAS), by cloud multiple scattering were made from an analytical method and from Monte Carlo calculations. The path delay of the return pulse was found to be largest for low-level clouds with particle radii (3-20 microns). The magnitude of the path delay was affected by several factors including cloud height, cloud optical depth, cloud particle size, particle shape, and receiver field of view. Polar aerosol and Rayleigh scattering usually added less than 1 cm to the overall path delay. Path delay estimates for all cloud conditions would be less if a simple Gaussian fit of the return pulse peak were used to measure the pulse's centroid. However, care must be taken in determining the centroid as factors such as pulse width, surface slope and the fitting method used will affect the estimate. A planned application for laser altimetry is high precision monitoring of the height change of polar ice sheets. In the absence of a correction algorithm, the required GLAS altimetry accuracies will not be achieved unless atmospheric channel information is used to remove profiles that are likely to be heavily contaminated by multiple scattering.
    Keywords: Geophysics
    Type: IEEE Transactions on Remote Sensing
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    A Study of Fixed-Order Mixed Norm Designs for a Benchmark Problem in Structural Control (1998)
    In:  Other Sources
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    Publication Date: 2011-08-23
    Description: This study investigates the use of H2, p-synthesis, and mixed H2/mu methods to construct full-order controllers and optimized controllers of fixed dimensions. The benchmark problem definition is first extended to include uncertainty within the controller bandwidth in the form of parametric uncertainty representative of uncertainty in the natural frequencies of the design model. The sensitivity of H2 design to unmodelled dynamics and parametric uncertainty is evaluated for a range of controller levels of authority. Next, mu-synthesis methods are applied to design full-order compensators that are robust to both unmodelled dynamics and to parametric uncertainty. Finally, a set of mixed H2/mu compensators are designed which are optimized for a fixed compensator dimension. These mixed norm designs recover the H, design performance levels while providing the same levels of robust stability as the u designs. It is shown that designing with the mixed norm approach permits higher levels of controller authority for which the H, designs are destabilizing. The benchmark problem is that of an active tendon system. The controller designs are all based on the use of acceleration feedback.
    Keywords: Geophysics
    Type: Earthquake Engineering and Structural Dynamics (ISSN 0098-8847); Volume 27; 1315-1330
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    Quantifying the Wave Driving of the Stratosphere (1999)
    In:  Other Sources
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    Publication Date: 2011-08-23
    Description: The zonal mean eddy heat flux is directly proportional to the wave activity that propagates from the troposphere into the stratosphere. This quantity is a simple eddy diagnostic which is easily calculated from conventional meteorological analyses. Because this "wave driving" of the stratosphere has a strong impact on the stratospheric temperature, it is necessary to compare the impact of the flux with respect to stratospheric radiative changes caused by greenhouse gas changes. Hence, we must understand the precision and accuracy of the heat flux derived from our global meteorological analyses. Herein, we quantify the stratospheric heat flux using five different meteorological analyses, and show that there are 30% differences between these analyses during the disturbed conditions of the northern hemisphere winter. Such large differences result from the planetary differences in the stationary temperature and meridional wind fields. In contrast, planetary transient waves show excellent agreement amongst these five analyses, and this transient heat flux appears to have a long term downward trend.
    Keywords: Geophysics
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    Evidence of Convection as a Dominant Source of Condensation Nuclei in the Northern Midlatitude Upper Troposphere (1999)
    In:  Other Sources
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    Publication Date: 2011-08-23
    Description: We examine concurrent upper tropospheric measurements of CN (diameter greater than 4 nm). NO, and NO(Y) during the SONEX Experiment over the North Atlantic (Oct.-Nov., 1997). Elevated CN and NO(Y) concentrations observed in the upper troposphere are attributed largely to enhancements in convective outflows. We estimate that less than 7% of observed high-CN plumes (greater than 10000 /cc) may be attributed to aircraft emissions. Dilution of high-CN convective and aircraft plumes appears to be much more rapid than losses of NO(X) and CN by oxidation and coagulation, respectively, and accounts for much of observed CN concentrations. When taking into account of different time scales against dilution for observable aircraft and convective high-CN plumes (estimated to be 1:4), the contribution by aircraft emissions to CN concentrations is significant, about 20% of the convective source. We find no evidence that particle formation in convective plumes is limited by OH oxidation of SO2.
    Keywords: Geophysics
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  • 88
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    Errors in the J(sub 3) Part of Nutation Series (1996)
    In:  Other Sources
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    Publication Date: 2011-08-23
    Description: This paper points out that the nutation terms of Zhu & Groten due to the tidal potential of degree 3 are erroneous. Correct values are deduced here and they coincide very well with those given in Kinoshita & Souchay. These errors explain the discrepancies between the evaluation of the theories of Zhu & Groten and Kinoshita & Souchay, which can reach values up to 165 micro arc second. Also the two leading nutation terms due to the tidal potential of degree 4 are given. Finally, some of the computer programs (NUTC.F, KSV_1994.F) for evaluating the,13 nutation terms are also erroneous.
    Keywords: Geophysics
    Type: Astronomical Journal (ISSN 0004-6256); Volume 3; No. 3; 1400-1404
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    Dual Spacecraft Observations of Lobe Magnetic Field Perturbations Before, During and after Plasmoid Release (1999)
    In:  Other Sources
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    Publication Date: 2011-08-23
    Description: This study examines a unique data set returned by IMP8 and Geotail on January 29, 1995 during a substorm which resulted in the ejection of a plasmoid. The two spacecraft (s/c) were situated in the north lobe of the tail and both observed a traveling compression region (TCR). From single s/c observations only the length of the plasmoid in X and an estimate of its height in Z can be determined. However, we show that dual s/c measurements of TCRs can be used to model all three dimensions of the underlying plasmoid and to estimate of its rate of expansion or contraction. For this event plasmoid dimensions of Delta(X) approximates 18, Delta(Y) approximates 30, and Delta(Z) approximates 10 R(sub e) are inferred from the IMP8 and Geotail lobe magnetic field measurements. The earthward end of the plasmoid was inferred to be near the mean location of the near-earth neutral line, X approximates -26 R(sub e). Its center was underneath IMP 8 at X approximates -34 R(sub e) and its tailward end appeared to be near X approximates -44 R(sub e). Furthermore, a factor of approximately 2 increase in the amplitude of the TCR occurred in the 1.5 min it took to move from IMP 8 to Geotail. Modeled using conservation of the magnetic flux, this increase in lobe compression implies that the underlying plasmoid was expanding at a rate of approximately 140 km/s. Such an expansion is comparable to recently reported V(sub y) speeds in "young" plasmoids in this region of the tail. Finally, the Geotail measurements indicate that a reconfiguration of the lobe magnetic field closely followed the ejection of the plasmoid which moved magnetic flux tubes into the wake behind the plasmoid where they would convect into the near-earth neutral line and reconnect.
    Keywords: Geophysics
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    Atmos/Atlas 3 Infrared Profile Measurements of Trace Gases in The November 1994 Tropical and Subtropical Upper Troposphere (1998)
    In:  Other Sources
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    Publication Date: 2011-08-23
    Description: Vertical mixing ratio profiles of four relatively long-lives gases, HCN, C2H2, CO, and C2H6, have been retrieved from 0.01/cm resolution infrared solar occultation spectra recorded between latitudes of 5.3degN and 31.4degN. The observations were obtained by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the Atmospheric Laboratory for Applications and Science (ATLAS) 3 shuttle flight, 3-12 November 1994. Elevated mixing ratios below the tropopause were measured for these gases during several of the occultations. The positive correlations obtained between the simultaneously measured mixing ratios suggest that the enhancements are likely the result of surface emissions, most likely biomass burning and/or urban industrial activities, followed by common injection via deep convective transport of the gases to the upper troposphere. The elevated levels of HCN may account for at least part of the "missing NO," in the upper troposphere. Comparisons of the observations with values measured during a recent aircraft campaign are presented.
    Keywords: Geophysics
    Type: Journal of Quantitative Spectroscopy and Radiative Transfer; Volume 60; No. 5; 891-901
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    Simulation of the December 1998 Stratospheric Major Warming (1999)
    In:  Other Sources
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    Publication Date: 2011-08-23
    Description: Prior to 1991, major warmings (defined by increasing zonal mean temperatures and zonal mean easterly winds from 60degN to the pole at 10 hPa) typically occurred approximately once every two Arctic winters; a major warming in mid-Dec. 1998 was the first since Feb. 1991. The Dec. 1998 warming was also the second earliest on record. The earliest, and the only other major warming on record before the end of Dec. was in early Dec 1987; prior to that, the earliest was in late Dec./early Jan. 1984-85. The 1984-85 and 1987 warmings resulted in the warmest and weakest lower stratospheric polar vortices in the 20 years before 1998-99. Fig. 1 compares temperatures and vortex strength in 1998-99 with those in the previous 20 years, using the US National Center for Environmental Prediction (NCEP) record; 1987-88 and 1984-85 are also highlighted. The Dec. 1998 warming had a more pronounced effect on mid-stratospheric temperatures than the Dec. 1987 warming (Fig. 1a), although smaller than that of warmings later in winter (e.g., 1984-85). 10-hPa temperatures fell well below average again in late Jan. 1999 and remained unusually low until an early final warming began in late Feb. 840 K PV gradients (Fig. 1c) set a record minimum in Jan. 1999, but were near average in Feb before the final warming. The effect of the Dec. 1998 warming on lower stratospheric temperatures was comparable to that of other major warmings; there was a brief period of record-high minimum 46-hPa temperatures in early Jan 1999 (Fig. 1b), and temperatures then fell to near average for a short period in mid-Feb. Lower stratospheric PV gradients were the weakest on record during the 1998-99 winter (Fig. 1d). The evolution of the vortex and minimum temperatures during 1998-99 was remarkably similar to that during 1987-88, the only previous year when a major warming was observed before the end of Dec.
    Keywords: Geophysics
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    Volatiles in the Desert: Subtle Remote-sensing Signatures of the Dakhleh Oasis Catastrophic Event, Western Desert, Egypt (2005)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Over the past decade members of the Dakhleh Oasis Project have studied enigmatic signatures in the Pleistocene geologic record of portions of the Dakhleh oasis and palaeo-oasis in Egypt's Western Desert [1,2]. In particular, Si-Ca-Al rich glass melt (Dakhleh Glass, Fig. 1) points to a catastrophic event between c.100,000-200,000 years ago [3] in this well-studied African savannah and freshwater lake Middle Stone Age environment [4,5].
    Keywords: Geophysics
    Type: Workshop on The Role of Volatile and Atmospheres on Martian Impact Craters; 44-45; LPI-Contrib-1273
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    Modern Uplift of the Transantarctic Mountains: Preliminary Results of an Autonomous GPS Array (1998)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: An autonomous GPS array is being implemented in the Transantarctic Mountains, sponsored by NSF and NASA, for the purpose of measuring uplift resulting from post-glacial rebound (PGR). The rebound of the solid earth due to unloading of ice since the Last Glacial Maximum is expected to dominate the measured uplift for most of West Antarctica, dwarfing the signals due to present-day ice sheet mass balance changes and tectonic motion, as long as mantle viscosity is greater than about 10(exp 20) Pa-s. Predicted uplift patterns have been calculated for a range of model scenarios, which illustrate how the uplift pattern might distinguish between different-sized ice sheets and deglaciation histories as represented by the competing models. The scenarios considered by James and Ivins (1998) include ICE-3G, CLIMAP and a variation of the CLIMAP model by Denton et al. For these models, peak uplift rates occur in the Transantarctic Mountains, and differences between models is often large there. Thus, the Transantarctic Mountains are an ideal place to obtain uplift measurements to constrain deglaciation models.
    Keywords: Geophysics
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    Performance of a Bounce-Averaged Global Model of Super-Thermal Electron Transport in the Earth's Magnetic Field (1998)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: In this paper, we report the results of our recent research on the application of a multiprocessor Cray T916 supercomputer in modeling super-thermal electron transport in the earth's magnetic field. In general, this mathematical model requires numerical solution of a system of partial differential equations. The code we use for this model is moderately vectorized. By using Amdahl's Law for vector processors, it can be verified that the code is about 60% vectorized on a Cray computer. Speedup factors on the order of 2.5 were obtained compared to the unvectorized code. In the following sections, we discuss the methodology of improving the code. In addition to our goal of optimizing the code for solution on the Cray computer, we had the goal of scalability in mind. Scalability combines the concepts of portabilty with near-linear speedup. Specifically, a scalable program is one whose performance is portable across many different architectures with differing numbers of processors for many different problem sizes. Though we have access to a Cray at this time, the goal was to also have code which would run well on a variety of architectures.
    Keywords: Geophysics
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    Visualization of High Latitude Ion Upflow in Support of the Image Mission (1996)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The study of the magnetosphere is a 400 year old science that began with the publication by Gilbert, in 1600, of his hypotheses that the Earth was a giant magnet. Since then we have learned many things about the magnetosphere, particularly in the last 40 years of the space age, but we still have many unanswered questions. In spite of the many thousands of observations of this system we still lack a global understanding of how it works. This is due to its large size and tenuous nature that mean that any measurement made of the fields or particles involved only give one a knowledge of the local conditions at a given time. To gain a global perspective through such observations would require the simultaneous operation of thousands of satellites spread throughout the magnetospheric system in addition to observations made on the ground. Such a program would be impractical at least from financial considerations. What is needed for the advancement of magnetospheric physics is to develop the same capabilities that astrophysicists, solar physicists and meteorologists have been using for years --- the ability to stand back from the object under study and see it in its entirety. The challenge for doing this for the magnetosphere is that the particle densities are very low and the material is, for the most part, not luminous. In the last 25 years several ideas have been proposed that would allow at least the imaging of certain portions of the magnetosphere. These include imaging of the plasmasphere through the resonant scattering of solar 304 A from He+ ions, imaging of various hot plasma populations (i.e. the ring current, plasmasheet, upflowing ionospheric ions, etc.) from the neutral atoms that result when ions of these populations charge exchange with the hydrogen geocorona, and imaging the aurora at various wavelengths in the far ultraviolet. In addition, a novel technique for probing various boundaries in the magnetosphere by bouncing low frequency radio waves off of them has been extensively studied. Such a technique is analogous to the way the under water world can be probed with sonar. About five years ago NASA convened a science working group to study the possibility of flying a magnetospheric imaging mission. This resulted in a number of proposals for such a mission, one of which was selected to be the first MIDEX mission, to be launched in early 2000. The mission is called IMAGE (Imager for Magnetopause to Aurora Global Exploration) and its P.I. is J. Burch at SwRI. The IMAGE spacecraft will carry imagers to view the plasmasphere, aurora, ring current, inner plasmasheet, and upflowing ionospheric ions as well as a radio sounder to probe the location, shape and dynamics of the magnetopause, plasmapause, etc. Between its selection last April and the non advocacy mission review, which takes place next spring, the IMAGE teams needs to further refine the design of the mission and its instruments. The theory and modeling (T&M) subgroup of this team has the task of demonstrating what kind of images the instruments on IMAGE will see as well as showing that useful scientific information can be extracted from such images. As a central element to the efforts of the T&M subgroup we have decided to simulate and create synthetic images for the magnetic cloud event of October, 1995. In this event a large cloud, with high plasma densities and strong magnetic fields, ejected from the sun collided with the earth's magnetosphere triggering a three day period of intense magnetic storms and substorms. This event was observed from a number of different spacecraft and on the ground so we have a good data set to work with. In our work we will place the IMAGE spacecraft in the magnetosphere on its proposed orbit, with its proposed instruments, to see what it would see had it been there. Existing models of the plasmasphere, ring current and magnetopause will be run for this event to give the structures for the imaging instruments. There are several models which are lacking and which need to be developed. These include a model for the cusp, the inner plasmasheet and the upflowing ions. My task this summer was to develop the upflowing ion model and use it to create synthetic images.
    Keywords: Geophysics
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    Homepage for the Global Tropospheric Experiment (1995)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The objective of my NASA summer research project was to create a homepage to describe and present results from the NASA Global Tropospheric Experiment (GTE). The GTE is a major component of NASA's Tropospheric Chemistry Program and is managed in the Atmospheric Studies Branch, Atmospheric Sciences Division at the NASA Langley Research Center.
    Keywords: Geophysics
    Type: Langley Aerospace Research Summer Scholars; Part 2; 791-798; NASA-CR-202464
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    A MATLAB/Simulink based GUI for the CERES Simulator (1995)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The Clouds and The Earth's Radiant Energy System (CERES) simulator will allow flight operational familiarity with the CERES instrument prior to launch. It will provide a CERES instrument simulation facility for NASA Langley Research Center. NASA Goddard Space Flight Center and TRW. One of the objectives of building this simulator would be for use as a testbed for functionality checking of atypical memory uploads and for anomaly investigation. For instance, instrument malfunction due to memory damage requires troubleshooting on a simulator to determine the nature of the problem and to find a solution.
    Keywords: Geophysics
    Type: Langley Aerospace Research Summer Scholars; Part 2; 769-779; NASA-CR-202464
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    Comparisons of Upper Tropospheric Humidity Retrievals from TOVS and METEOSAT (1999)
    In:  CASI
    Details
    Publication Date: 2013-08-29
    Description: Two different methods for retrieving Upper Tropospheric Humidities (UTH) from the TOVS (TIROS Operational Vertical Sounder) instruments aboard NOAA polar orbiting satellites are presented and compared. The first one, from the Environmental Technology Laboratory, computed by J. Bates and D. Jackson (hereafter BJ method), estimates UTH from a simplified radiative transfer analysis of the upper tropospheric infrared water vapor channel at wavelength measured by HIRS (6.3 micrometer). The second one results from a neural network analysis of the TOVS (HIRS and MSU) data developed at, the Laboratoire de Meteorologie Dynamique (hereafter the 3I (Improved Initialization Inversion) method). Although the two methods give very similar retrievals in temperate regions (30-60 N and S), an absolute bias up to 16% appears in the convective zone of the tropics. The two datasets have also been compared with UTH retrievals from infrared radiance measurements in the 6.3 micrometer channel from the geostationary satellite METEOSAT (hereafter MET method). The METEOSAT retrievals are systematically drier than the TOVS-based results by an absolute bias between 5 and 25%. Despite the biases, the spatial and temporal correlations are very good. The purpose of this study is to explain the deviations observed between the three datasets. The sensitivity of UTH to air temperature and humidity profiles is analysed as are the clouds effects. Overall, the comparison of the three retrievals gives an assessment of the current uncertainties in water vapor amounts in the upper troposphere as determined from NOAA and METEOSAT satellites.
    Keywords: Geophysics
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    Magnetism of Carbonados (1999)
    In:  CASI
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    Publication Date: 2013-08-29
    Description: Carbonados are porous polycrystalline (with crystal sizes up to 100 micrometer) diamonds. Carbonado is found only in alluvial deposits in Bahia, Brazil and in the Central African Republic (CAR). Alluvial deposit host is 1.5 Ga while the carbonados are between 2.6 - 3.8 Ga. The process of fusing the carbonado microcrystals together is not fully understood, partly due to fact that the origin of these carbonado, is not known. Several modes of origins are proposed for carbonado. First, a crustal origin. Carbonados have a light carbon and helium isotopic signature. They contain an enrichment of the rare-earth elements (REE). Carbonados have tightly trapped atmospheric noble gases and contain an evidence of high He content despite the carbonado expected depletion of He at mantle temperatures. Carbonados have high porosity incompatible with high pressure mantle conditions. Second, a mantle origin is proposed based on similar REE pattern to kimberlites. The presence of nitrogen platelet (by IR spectra) indicates high temperature origin and syngenetic inclusions of rutile, ilmenite, and magnetite indicates high pressure and high temperature conditions consistent with mantle origin as well. Third, it is proposed that carbonado diamonds are a result of early impacts into crustal rocks. This is indicated by the rare and controversial occurrence of high pressure diamond polymorph, londsdaleite, frequently found in diamonds from meteorite impact sites, and by observation of planar deformation features, possibly indicating shock events. Finally, it is suggested that carbonados have an extraterrestrial origin, as indicated by a long term annealing based on observation of a zero-phonon line, attributed to paired nitrogen atoms in association with a vacancy.
    Keywords: Geophysics
    Type: Lunar and Planetary Science Conference; United States
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    Extremely Low Ionospheric Peak Altitudes in the Polar-Hole Region (1999)
    In:  CASI
    Details
    Publication Date: 2013-08-29
    Description: Vertical electron-density (N (sub e)) profiles, deduced from newly-available ISIS-II digital ionospheric topside-sounder data, are used to investigate the "polar-hole" region within the winter, nighttime polar cap ionosphere during solar minimum. The hole region is located around 0200 MLT near the poleward side of the auroral oval. Earlier investigations had revealed very low N (sub e) values in this region (down to 200/cu cm near 300 km). In the present study, such low N, values (approx. 100/cu cm) were only found near the ISIS (International Satellite for Ionospheric Study)-II altitude of 1400 km. The peak ionospheric concentration below the spacecraft remained fairly constant (approx. 10 (exp 5)/cu cm across the hole region but the altitude of the peak dropped dramatically. This peak dropped, surprisingly, to the vicinity of 100 km. These observations suggest that the earlier satellite in situ measurements, interpreted as deep holes in the ionospheric F-region concentration, could have been made during conditions of an extreme decrease in the altitude of the ionospheric N (sub e) peak. The observations, in combination with other data, indicate that the absence of an F-layer peak may be a frequent occurrence at high latitudes.
    Keywords: Geophysics
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