Science.gov

Sample records for topography gmrt synthesis

  1. Accessing the Global Multi-Resolution Topography (GMRT) Synthesis through Gmrt Maptool

    NASA Astrophysics Data System (ADS)

    Ferrini, V. L.; Morton, J. J.; Barg, B.; Carbotte, S. M.

    2014-12-01

    The Global Multi-Resolution Topography (GMRT) Synthesis (http://gmrt.marine-geo.org) is a dynamically maintained global multi-resolution synthesis of terrestrial and seafloor elevation data maintained as both images and gridded data values as part of the IEDA Marine Geoscience Data System. GMRT seamlessly brings together a variety of elevation sources, and includes ship-based multibeam sonar collected throughout the global oceans that is processed by the GMRT Team and is gridded to 100-m resolution. New versions of GMRT are released twice each year, typically adding processed multibeam data from ~80 cruises per year. GMRT grids and images can be accessed through a variety of tools and interfaces including GeoMapApp (http://www.geomapapp.org) the GMRT MapTool (http://www.marine-geo.org/tools/maps_grids.php), and images can also be accessed through a Web Map Service. We have recently launched a new version of our web-based GMRT MapTool interface, which provides custom access to the gridded data values in standard formats including GeoTIFF, ArcASCII and GMT NetCDF. Several resolution options are provided for these gridded data, and corresponding images can also be generated. Coupled with this new interface is an XML metadata service that provides attribution information and detailed metadata about source data components (cruise metadata, sensor metadata, and full list of source data files) for any region of interest. Metadata from the attribution service is returned to the user along with the requested data, and is also combined with the data itself in new Bathymetry Attributed Grid (BAG) formatted files.

  2. FIGGS: Faint Irregular Galaxies GMRT Survey - Overview, observations and first results

    E-print Network

    Ayesha Begum; Jayaram N. Chengalur; I. D. Karachentsev; M. E. Sharina; S. S. Kaisin

    2008-02-27

    The Faint Irregular Galaxies GMRT Survey (FIGGS) is a Giant Metrewave Radio Telescope (GMRT) based HI imaging survey of a systematically selected sample of extremely faint nearby dwarf irregular galaxies. The primary goal of FIGGS is to provide a comprehensive and statistically robust characterization of the neutral inter-stellar medium properties of faint, gas rich dwarf galaxies. The FIGGS galaxies represent the extremely low-mass end of the dwarf irregular galaxies population, with a median M${\\rm{_B\\sim-13.0}}$ and median HI mass of $\\sim 3 \\times 10^7$ M$_\\odot$, extending the baseline in mass and luminosity space for a comparative study of galaxy properties. The HI data is supplemented with observations at other wavelengths. In addition, distances accurate to ~ 10% are available for most of the sample galaxies. This paper gives an introduction to FIGGS, describe the GMRT observations and presents the first results from the HI observations. From the FIGGS data we confirm the trend of increasing HI to optical diameter ratio with decreasing optical luminosity; the median ratio of D$_{\\rm HI}$/D$_{\\rm Ho}$ for the FIGGS sample is 2.4. Further, on comparing our data with aperture synthesis surveys of bright spirals, we find at best marginal evidence for a decrease in average surface density with decreasing HI mass. To a good approximation the disks of gas rich galaxies, ranging over 3 orders of magnitude in HI mass, can be described as being drawn from a family with constant HI surface density.

  3. Rate and topography of peptidoglycan synthesis during cell division in Escherichia coli: Concept of a leading edge

    SciTech Connect

    Wientjes, F.B.; Nanninga, N. )

    1989-06-01

    The rate at which the peptidoglycan of Escherichia coli is synthesized during the division cycle was studied with two methods. One method involved synchronization of E. coli MC4100 lysA cultures by centrifugal elutriation and subsequent pulse-labeling of the synchronously growing cultures with (meso-{sup 3}H)diaminopimelic acid (({sup 3}H)Dap). The second method was autoradiography of cells pulse-labeled with ({sup 3}H)Dap. It was found that the peptidoglycan is synthesized at a more or less exponentially increasing rate during the division cycle with a slight acceleration in this rate as the cells start to constrict. Apparently, polar cap formation requires synthesis of extra surface components, presumably to accommodate for a change in the surface-to-volume ratio. Furthermore, it was found that the pool size of Dap was constant during the division cycle. Close analysis of the topography of ({sup 3}H)Dap incorporation at the constriction site revealed that constriction proceeded by synthesis of peptidoglycan at the leading edge of the invaginating cell envelope. During constriction, no reallocation of incorporation occurred, i.e., the incorporation at the leading edge remained high throughout the process of constriction. Impairment of penicillin-binding protein 3 by mutation or by the specific {beta}-lactam antibiotic furazlocillin did not affect ({sup 3}H)Dap incorporation during initiation of constriction. However, the incorporation at the constriction site was inhibited in later stages of the constriction process. It is concluded that during division at least two peptidoglycan-synthesizing systems are operating sequentially.

  4. A real-time software backend for the GMRT

    NASA Astrophysics Data System (ADS)

    Roy, Jayanta; Gupta, Yashwant; Pen, Ue-Li; Peterson, Jeffrey B.; Kudale, Sanjay; Kodilkar, Jitendra

    2010-08-01

    The new era of software signal processing has a large impact on radio astronomy instrumentation. Our design and implementation of a 32 antennae, 33 MHz, dual polarization, fully real-time software backend for the GMRT, using only off-the-shelf components, is an example of this. We have built a correlator and a beamformer, using PCI-based ADC cards and a Linux cluster of 48 nodes with dual gigabit inter-node connectivity for real-time data transfer requirements. The highly optimized compute pipeline uses cache efficient, multi-threaded parallel code, with the aid of vectorized processing. This backend allows flexibility in final time and frequency resolutions, and the ability to implement algorithms for radio frequency interference rejection. Our approach has allowed relatively rapid development of a fairly sophisticated and flexible backend receiver system for the GMRT, which will greatly enhance the productivity of the telescope. In this paper we describe some of the first lights using this software processing pipeline. We believe this is the first instance of such a real-time observatory backend for an intermediate sized array like the GMRT.

  5. Facile synthesis of hydrangea flower-like hierarchical gold nanostructures with tunable surface topographies for single-particle surface-enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Song, C. Y.; Zhou, N.; Yang, B. Y.; Yang, Y. J.; Wang, L. H.

    2015-10-01

    The physicochemical properties of noble metal nanocrystals depend strongly on their size and shape, and it is becoming clear that the design and facile synthesis of particular nanostructures with tailored shape and size is especially important. Herein a novel class of hydrangea flower-like hierarchical gold nanostructures with tunable surface topographies and optical properties are prepared for the first time by a facile, one-pot, seedless synthesis using ascorbic acid (AA) to reduce hydrogen tetrachloroaurate (HAuCl4) in the presence of (1-hexadecyl)trimethylammonium chloride (CTAC). The morphologies of the synthesized gold nanoflowers are controlled and fine-tuned by varying the synthetic conditions such as the concentration of reagents and the growth temperature. Due to their unique hierarchical three-dimensional (3D) structures with rich hot spots, these gold nanoflowers exhibit an efficient performance in single-particle surface-enhanced Raman scattering (SERS). The work stands out as an interesting approach for anisotropic particle synthesis and morphological control, and the proposed novel, hierarchical gold nanoflowers have a number of exciting potential applications in SERS-based sensors.The physicochemical properties of noble metal nanocrystals depend strongly on their size and shape, and it is becoming clear that the design and facile synthesis of particular nanostructures with tailored shape and size is especially important. Herein a novel class of hydrangea flower-like hierarchical gold nanostructures with tunable surface topographies and optical properties are prepared for the first time by a facile, one-pot, seedless synthesis using ascorbic acid (AA) to reduce hydrogen tetrachloroaurate (HAuCl4) in the presence of (1-hexadecyl)trimethylammonium chloride (CTAC). The morphologies of the synthesized gold nanoflowers are controlled and fine-tuned by varying the synthetic conditions such as the concentration of reagents and the growth temperature. Due to their unique hierarchical three-dimensional (3D) structures with rich hot spots, these gold nanoflowers exhibit an efficient performance in single-particle surface-enhanced Raman scattering (SERS). The work stands out as an interesting approach for anisotropic particle synthesis and morphological control, and the proposed novel, hierarchical gold nanoflowers have a number of exciting potential applications in SERS-based sensors. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04827c

  6. Facile synthesis of hydrangea flower-like hierarchical gold nanostructures with tunable surface topographies for single-particle surface-enhanced Raman scattering.

    PubMed

    Song, C Y; Zhou, N; Yang, B Y; Yang, Y J; Wang, L H

    2015-10-01

    The physicochemical properties of noble metal nanocrystals depend strongly on their size and shape, and it is becoming clear that the design and facile synthesis of particular nanostructures with tailored shape and size is especially important. Herein a novel class of hydrangea flower-like hierarchical gold nanostructures with tunable surface topographies and optical properties are prepared for the first time by a facile, one-pot, seedless synthesis using ascorbic acid (AA) to reduce hydrogen tetrachloroaurate (HAuCl4) in the presence of (1-hexadecyl)trimethylammonium chloride (CTAC). The morphologies of the synthesized gold nanoflowers are controlled and fine-tuned by varying the synthetic conditions such as the concentration of reagents and the growth temperature. Due to their unique hierarchical three-dimensional (3D) structures with rich hot spots, these gold nanoflowers exhibit an efficient performance in single-particle surface-enhanced Raman scattering (SERS). The work stands out as an interesting approach for anisotropic particle synthesis and morphological control, and the proposed novel, hierarchical gold nanoflowers have a number of exciting potential applications in SERS-based sensors. PMID:26416701

  7. VizieR Online Data Catalog: LBDS-Lynx region GMRT 150-MHz obs. (Ishwara-Chandra+, 2010)

    NASA Astrophysics Data System (ADS)

    Ishwara-Chandra, C. H.; Sirothia, S. K.; Wadadekar, Y.; Pal, S.; Windhorst, R.

    2011-08-01

    It has been known for nearly three decades that high-redshift radio galaxies exhibit steep radio spectra, and hence ultrasteep spectrum radio sources provide candidates for high-redshift radio galaxies. Nearly all radio galaxies with z>3 have been found using this redshift-spectral index correlation. We have started a programme with the Giant Metrewave Radio Telescope (GMRT) to exploit this correlation at flux density levels about 10 to 100 times deeper than the known high-redshift radio galaxies which were identified primarily using the already available radio catalogues. In our programme, we have obtained deep, high-resolution radio observations at 150MHz with GMRT for several "deep" fields which are well studied at higher radio frequencies and in other bands of the electromagnetic spectrum, with an aim to detect candidate high-redshift radio galaxies. In this paper we present results from the deep 150-MHz observations of the LBDS-Lynx field (Leiden-Berkeley Deep Survey), which has been already imaged at 327, 610 and 1412MHz with the Westerbork Synthesis Radio Telescope and at 1400 and 4860MHz with the Very Large Array. (2 data files).

  8. A software baseband receiver for pulsar astronomy at GMRT

    E-print Network

    Bhal Chandra Joshi; Sunil Ramakrishna

    2006-11-10

    A variety of pulsar studies, ranging from high precision astrometry to tests for theories of gravity, require high time resolution data. Few such observations at more than two frequencies below 1 GHz are available. Giant Meterwave Radio Telescope (GMRT) has the unique capability to provide such multi-frequency pulsar data at low observation frequencies, but the quality and time resolution of pulsar radio signals is degraded due to dispersion in the inter-stellar medium at these frequencies. Such degradation is usually taken care of by employing specialized digital hardware, which implement coherent dedispersion algorithm. In recent years, a new alternative is provided by the availability of cheap computer hardware. In this approach, the required signal processing is implemented in software using commercially off-the-shelf available computing hardware. This makes such a receiver flexible and upgradeable unlike a hardware implementation. The salient features and the modes of operation of a high time resolution pulsar instrument for GMRT based on this approach is described in this paper. The capability of the instrument is demonstrated by illustrations of test observations. We have obtained the average profile of PSR B1937+21 at 235 MHz for the first time and this profile indicates a scattering timescale of about 300 us. Lastly, the possible future extensions of this concept are discussed.

  9. GMRT observations of X-shaped radio sources

    E-print Network

    Dharam Vir Lal; A. Pramesh Rao

    2006-10-23

    We present results from a study of X-shaped sources based on observations using the Giant Metrewave Radio Telescope (GMRT). These observations were motivated by our low frequency study of 3C 223.1 (Lal & Rao 2005), an X-shaped radio source, which showed that the wings (or low-surface-brightness jets) have flatter spectral indices than the active lobes (or high-surface-brightness jets), a result not easily explained by most models. We have now obtained GMRT data at 240 and 610 MHz for almost all the known X-shaped radio sources and have studied the distribution of the spectral index across the sources. While the radio morphologies of all the sources at 240 and 610 MHz show the characteristic X-shape, the spectral characteristics of the X-shaped radio sources, seem to fall into three categories, namely, sources in which (A) the wings have flatter spectral indices than the active lobes, (B) the wings and the active lobes have comparable spectral indices, and (C) the wings have steeper spectral indices than the active lobes. We discuss the implications of the new observational results on the various formation models that have been proposed for X-shaped sources.

  10. GMRT HI observations of the Eridanus group of galaxies

    E-print Network

    A. Omar; K. S. Dwarakanath

    2005-03-24

    The GMRT HI 21cm-line observations of galaxies in the Eridanus group are presented. The Eridanus group, at a distance of ~23 Mpc, is a loose group of \\~200 galaxies. The group extends more than 10 Mpc in projection. The velocity dispersion of the galaxies in the group is ~240 km/s. The galaxies are clustered into different sub-groups. The overall population mix of the group is 30% (E+S0) and 70% (Sp+Irr). The observations of 57 Eridanus galaxies were carried out with the GMRT for ~200 hour. HI emission was detected from 31 galaxies. The channel rms of ~1.0 mJy beam^{-1} was achieved for most of the image-cubes made with 4 hour of data. The corresponding HI column density sensitivity (3-sigma) is ~1x10^{20} cm^{-2} for a velocity-width of ~13.4 km/s. The 3-sigma detection limit of HI mass is ~1.2x10^{7} M_sun for a line-width of 50 km/s. Total HI images, HI velocity fields, global HI line profiles, HI mass surface densities, HI disk parameters and HI rotation curves are presented. The velocity fields are analysed separately for the approaching and the receding sides of the galaxies. This data will be used to study the HI and the radio continuum properties, the Tully-Fisher relations, the dark matter halos, and the kinematical and HI lopsidedness in galaxies.

  11. Improved foreground removal in GMRT 610 MHz observations towards redshifted 21-cm tomography

    E-print Network

    Ghosh, Abhik; Ali, Sk Saiyad; Chengalur, Jayaram N

    2011-01-01

    Foreground removal is a challenge for 21-cm tomography of the high redshift Universe. We use archival GMRT data (obtained for completely different astronomical goals) to estimate the foregrounds at a redshift ~ 1. The statistic we use is the cross power spectrum between two frequencies separated by \\Delta{\

  12. VizieR Online Data Catalog: GMRT Radio Halo Cluster Survey diffuse sources (Venturi+, 2013)

    NASA Astrophysics Data System (ADS)

    Venturi, T.; Giacintucci, S.; Dallacasa, D.; Cassano, R.; Brunetti, G.; Macario, G.; Athreya, R.

    2012-11-01

    High sensitivity imaging was performed using the GMRT at 325MHz and 240MHz. The properties of the diffuse emission in each cluster were compared to our 610MHz images and/or literature information available at other frequencies, in order to derive the integrated spectra over a wide frequency range. (5 data files).

  13. The Extended GMRT Radio Halo Survey II: Further results and analysis of the full sample

    E-print Network

    Kale, R; Giacintucci, S; Dallacasa, D; Cassano, R; Brunetti, G; Cuciti, V; Macario, G; Athreya, R

    2015-01-01

    The intra-cluster medium contains cosmic rays and magnetic fields that are manifested through the large scale synchrotron sources, termed as radio halos, relics and mini-halos. The Extended Giant Metrewave Radio Telescope (GMRT) Radio Halo Survey (EGRHS) is an extension of the GMRT Radio Halo Survey (GRHS) designed to search for radio halos using GMRT 610/235 MHz observations. The GRHS+EGRHS consists of 64 clusters in the redshift range 0.2 -- 0.4 that have an X-ray luminosity larger than 5x10^44 erg/s in the 0.1 -- 2.4 keV band and with declinations > -31 deg in the REFLEX and eBCS X-ray cluster catalogues. In this second paper in the series, GMRT 610/235 MHz data on the last batch of 11 galaxy clusters and the statistical analysis of the full sample are presented. A new mini-halo in RXJ2129.6+0005 and candidate diffuse sources in Z5247, A2552 and Z1953 are discovered. A unique feature of this survey are the upper limits on the detections of 1 Mpc sized radio halos; 4 new are presented here making a total of...

  14. GMRT Low frequency radio observation of Cyg X-3 at the time of flare

    NASA Astrophysics Data System (ADS)

    Pal, Sabyasachi; Rao, A. Pramesh

    2007-06-01

    Trushkin et al. (#Atel 1092) detected beginning of a new flaring activity in galactic black hole candidate Cygnus X-3. We have observed the source from UT 2.99 June to 3.08 June, 2007 in 243 and 614 MHz frequencies using Giant Meterwave Radio Telescope (GMRT). The source was variable and seemed to rise during our observation.

  15. HI Fluctuations at Large Redshifts: III - Simulating the Signal Expected at GMRT

    E-print Network

    Somnath Bharadwaj; Pennathur Sridharan Srikant

    2004-02-11

    We simulate the distribution of neutral hydrogen (HI) at the redshifts z=1.3 and 3.4 using a cosmological N-body simulation along with a prescription for assigning HI masses to the particles. The HI is distributed in clouds whose properties are consistent with those of the damped Lyman-\\alpha absorption systems (DLAs) seen in quasar spectra. The clustering properties of these clouds are identical to those of the dark matter. We use this to simulate the redshifted HI emission expected at 610 MHz and 325 MHz, two of the observing bands a the GMRT. These are used to predict the correlations expected between the complex visibilities measured at different baselines and frequencies in radio-interferometric observations with the GMRT. The visibility correlations directly probe the power spectrum of HI fluctuations at the epoch when the HI emission originated, and this holds the possibility of using HI observations to study large-scale structures at high z.

  16. Facile Synthesis of Conductive Polypyrrole Wrinkle Topographies on Polydimethylsiloxane via a Swelling-Deswelling Process and Their Potential Uses in Tissue Engineering.

    PubMed

    Aufan, M Rifqi; Sumi, Yang; Kim, Semin; Lee, Jae Young

    2015-10-28

    Electrically conducting biomaterials have gained great attention in various biomedical studies especially to influence cell and tissue responses. In addition, wrinkling can present a unique topography that can modulate cell-material interactions. In this study, we developed a simple method to create wrinkle topographies of conductive polypyrrole (wPPy) on soft polydimethylsiloxane surfaces via a swelling-deswelling process during and after PPy polymerization and by varying the thickness of the PPy top layers. As a result, various features of wPPy in the range of the nano- and microscales were successfully obtained. In vitro cell culture studies with NIH 3T3 fibroblasts and PC12 neuronal cells indicated that the conductive wrinkle topographies promote cell adhesion and neurite outgrowth of PC12 cells. Our studies help to elucidate the design of the surface coating and patterning of conducting polymers, which will enable us to simultaneously provide topographical and electrical signals to improve cell-surface interactions for potential tissue-engineering applications. PMID:26444932

  17. Engineering Topography of extracellular microenvironment

    E-print Network

    Chemical Engineering Abstract Topography of extracellular microenvironment can influence cellular. Nanoscaled topography of synthetic materials, through its resemblance to in vivo surroundings, may provide the potential of applying topography to enhance nonviral transfection. Optimization of nonviral gene delivery

  18. OpenTopography

    NASA Astrophysics Data System (ADS)

    Baru, C.; Arrowsmith, R.; Crosby, C.; Nandigam, V.; Phan, M.; Cowart, C.

    2012-04-01

    OpenTopography is a cyberinfrastructure-based facility for online access to high-resolution topography and tools. The project is an outcome of the Geosciences Network (GEON) project, which was a research project funded several years ago in the US to investigate the use of cyberinfrastructure to support research and education in the geosciences. OpenTopography provides online access to large LiDAR point cloud datasets along with services for processing these data. Users are able to generate custom DEMs by invoking DEM services provided by OpenTopography with custom parameter values. Users can track the progress of their jobs, and a private myOpenTopo area retains job information and job outputs. Data available at OpenTopography are provided by a variety of data acquisition groups under joint agreements and memoranda of understanding (MoU). These include national facilities such as the National Center for Airborne Lidar Mapping, as well as local, state, and federal agencies. OpenTopography is also being designed as a hub for high-resolution topography resources. Datasets and services available at other locations can also be registered here, providing a "one-stop shop" for such information. We will describe the OpenTopography system architecture and its current set of features, including the service-oriented architecture, a job-tracking database, and social networking features. We will also describe several design and development activities underway to archive and publish datasets using digital object identifiers (DOIs); create a more flexible and scalable high-performance environment for processing of large datasets; extend support for satellite-based and terrestrial lidar as well as synthetic aperture radar (SAR) data; and create a "pluggable" infrastructure for third-party services. OpenTopography has successfully created a facility for sharing lidar data. In the next phase, we are developing a facility that will also enable equally easy and successful sharing of services related to these data.

  19. Dynamic Topography Revisited

    NASA Astrophysics Data System (ADS)

    Moresi, Louis

    2015-04-01

    Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The relationship between surface topography, gravity anomalies, and temperature structure of convection, Journal of Geophysical Research: Solid Earth (1978-2012), 88(B2), 1129-1144, doi:10.1029/JB088iB02p01129. [3] Robinson, E. M., B. Parsons, and S. F. Daly (1987), The effect of a shallow low viscosity zone on the apparent compensation of mid-plate swells, Earth and Planetary Science Letters, 82(3-4), 335-348, doi:10.1016/0012-821X(87)90207-X.

  20. X Ray Topography

    ERIC Educational Resources Information Center

    Balchin, A. A.

    1974-01-01

    Discusses some aspects in X-ray topography, including formation of dislocations, characteristics of stacking faults, x-ray contrast in defect inspection, Berg-Barrett technique, and Lang traversing crystal and Borrmann's methods. (CC)

  1. The Extended GMRT Radio Halo Survey. II. Further results and analysis of the full sample

    NASA Astrophysics Data System (ADS)

    Kale, R.; Venturi, T.; Giacintucci, S.; Dallacasa, D.; Cassano, R.; Brunetti, G.; Cuciti, V.; Macario, G.; Athreya, R.

    2015-07-01

    The intra-cluster medium contains cosmic rays and magnetic fields that are manifested through the large scale synchrotron sources, termed radio haloes, relics, and mini-haloes. The Extended Giant Metrewave Radio Telescope (GMRT) Radio Halo Survey (EGRHS) is an extension of the GMRT Radio Halo Survey (GRHS) designed to search for radio haloes using GMRT 610/235 MHz observations. The GRHS and EGRHS consists of 64 clusters in the redshift range 0.2-0.4 that have an X-ray luminosity larger than 5 × 1044 erg s-1 in the 0.1-2.4 keV band and declination, ? > -31° in the REFLEX and eBCS X-ray cluster catalogues. In this second paper in the series, GMRT 610/235 MHz data on the last batch of 11 galaxy clusters and the statistical analysis of the full sample are presented. A new mini-halo in RX J2129.6+0005 and candidate diffuse sources in Z5247, A2552, and Z1953 have been discovered. A unique feature of this survey are the upper limits on the detections of 1 Mpc sized radio haloes; 4 new are presented here, making a total of 31 in the survey. Of the sample, 58 clusters with adequately sensitive radio information were used to obtain the most accurate occurrence fractions so far. The occurrence fractions of radio haloes, mini-haloes and relics in our sample are ~22%, ~16% and ~5%, respectively. The P1.4 GHz-LX diagrams for the radio haloes and mini-haloes are presented. The morphological estimators - centroid shift (w), concentration parameter (c), and power ratios (P3/P0) derived from the Chandra X-ray images - are used as proxies for the dynamical states of the GRHS and EGRHS clusters. The clusters with radio haloes and mini-haloes occupy distinct quadrants in the c-w, c-P3/P0 and w-P3/P0 planes, corresponding to the more and less morphological disturbance, respectively. The non-detections span both the quadrants. Appendices are available in electronic form at http://www.aanda.org

  2. Low-frequency GMRT observations of the magnetic Bp star HR Lup (HD 133880)

    NASA Astrophysics Data System (ADS)

    George, Samuel J.; Stevens, Ian R.

    2012-06-01

    We present radio observations of the magnetic chemically peculiar Bp star HR Lup (HD 133880) at 647 and 277 MHz with the GMRT. At both frequencies the source is not detected but we are able to determine upper limits to the emission. The 647 MHz limits are particularly useful, with a 5? value of 0.45 mJy. Also, no large enhancements of the emission were seen. The non-detections, along with previously published higher frequency detections, provide evidence that an optically thick gyrosynchrotron model is the correct mechanism for the radio emission of HR Lup.

  3. GMRT discovery of a 1.69 ms radio pulsar associated with XSS J12270-4859

    NASA Astrophysics Data System (ADS)

    Roy, J.; Bhattacharyya, B.; Ray, P. S.

    2014-02-01

    Following the reported state change observed in the low-mass X-ray binary XSS J12270-4859 (ATel #5647; Bassa et al. 2014, arXiv:1402.0765), we were granted Director's Discretionary Time to search for radio pulsations using the GMRT. We observed at 607 MHz with the GMRT coherent phased-array mode utilizing 70% of the array resulting in a beam width of 30 arcsec. We recorded 3 scans, each of 1-hour beginning on 2014 Feb 12 at 20:46:15 UTC, producing filter-bank outputs of 512 x 0.0651 MHz sampled at 61.44 microsec.

  4. Universal multifractal Martian topography

    NASA Astrophysics Data System (ADS)

    Landais, F.; Schmidt, F.; Lovejoy, S.

    2015-07-01

    In the present study, we investigate the scaling properties of the topography of Mars. Planetary topographic fields are well known to roughly exhibit (mono)fractal behavior. Indeed, the fractal formalism is reproduces much of the variability observed in topography. Still, a single fractal dimension is not enough to explain the huge variability and intermittency. Previous studies have claimed that fractal dimensions might be different from one region to an other, excluding a general description at the planetary scale. In this article, we are analyzing the Martian topographic data with a multifractal formalism to study the scaling intermittency. In the multifractal paradigm, the apparent local variation of the fractal dimension is interpreted as a statistical property of multifractal fields. We analyze the topography measured with the laser altimeter MOLA at 300 m horizontal resolution, 1 m vertical resolution. We adapted the Haar fluctuation method to the the irregularly sampled signal. The results suggest a multifractal behavior from planetary scale down to 10 km. From 10 km to 300 m, the topography seems to be simple monofractal. This transition indicates a significant change in the geological processes governing the Red Planet's surface.

  5. Universal multifractal Martian topography

    NASA Astrophysics Data System (ADS)

    Landais, F.; Schmidt, F.; Lovejoy, S.

    2015-11-01

    In the present study, we investigate the scaling properties of the topography of Mars. Planetary topographic fields are well known to roughly exhibit (mono)fractal behavior. Indeed, the fractal formalism reproduces much of the variability observed in topography. Still, a single fractal dimension is not enough to explain the huge variability and intermittency. Previous studies have claimed that fractal dimensions might be different from one region to another, excluding a general description at the planetary scale. In this article, we analyze the Martian topographic data with a multifractal formalism to study the scaling intermittency. In the multifractal paradigm, the apparent local variation of the fractal dimension is interpreted as a statistical property of multifractal fields. We analyze the topography measured with the Mars Orbiter Laser altimeter (MOLA) at 300 m horizontal resolution, 1 m vertical resolution. We adapted the Haar fluctuation method to the irregularly sampled signal. The results suggest a multifractal behavior from the planetary scale down to 10 km. From 10 to 300 m, the topography seems to be simple monofractal. This transition indicates a significant change in the geological processes governing the Red Planet's surface.

  6. Tidal Conversion by Supercritical Topography

    E-print Network

    Balmforth, Neil J.

    Calculations are presented of the rate of energy conversion of the barotropic tide into internal gravity waves above topography on the ocean floor. The ocean is treated as infinitely deep, and the topography consists of ...

  7. A complete radio study of SNR G15.4+0.1 from new GMRT observations

    NASA Astrophysics Data System (ADS)

    Supan, L.; Castelletti, G.; Joshi, B. C.; Surnis, M. P.; Supanitsky, D.

    2015-04-01

    Aims: The supernova remnant (SNR) G15.4+0.1 is considered to be the possible counterpart of the ?-ray source HESS J1818-154. With the goal of getting a complete view of this remnant and understanding the nature of the ?-ray flux, we conducted a detailed radio study that includes the search for pulsations and a model of the broadband emission for the SNR G15.4+0.1/HESS J1818-154 system. Methods: Low-frequency imaging at 624 MHz and pulsar observations at 624 and 1404 MHz towards G15.4+0.1 were carried out with the Giant Metrewave Radio Telescope (GMRT). We correlated the new radio data with observations of the source at X-ray and infrared wavelengths from XMM-Newton and Herschel observatories, respectively. To characterize the neutral hydrogen (HI) medium towards G15.4+0.1, we used data from the Southern Galactic Plane Survey. We modelled the spectral energy distribution (SED) using both hadronic and leptonic scenarios. Results: From the combination of the new GMRT observations with existing data, we derived a continuum spectral index ? = -0.62 ± 0.03 for the whole remnant. The local synchrotron spectra of G15.4+0.1, calculated from the combination of the GMRT data with 330 MHz observations from the Very Large Array, tends to be flatter in the central part of the remnant, accompanying the region where the blast wave is impinging molecular gas. No spectral index trace was found indicating the radio counterpart to the pulsar wind nebula proposed from X-ray observations. In addition, the search for radio pulsations yielded negative results. Emission at far-infrared wavelengths is observed in the region where the SNR shock is interacting with dense molecular clumps. We also identified HI features forming a shell that wraps most of the outer border of G15.4+0.1. Characteristic parameters were estimated for the shocked HI gas. We found that either a purely hadronic or leptonic model is compatible with the broadband emission known so far.

  8. HI Fluctuations at Large Redshifts: II - the Signal Expected for GMRT

    E-print Network

    Somnath Bharadwaj; Sanjay K. Pande

    2003-07-16

    For the GMRT, we calculate the expected signal from redshifted HI emission at two frequency bands centered at 610 and 325 MHz. The study focuses on the visibility-visibility cross-correlations, proposed earlier as the optimal statistical estimator for detecting and analyzing this signal. These correlations directly probe the power spectrum of density fluctuations at the redshift where the radiation originated, and thereby provide a method for studying the large scale structures at large redshifts. We present detailed estimates of the correlations expected between the visibilities measured at different baselines and frequencies. Analytic fitting formulas representing the salient features of the expected signal are also provided. These will be useful in planning observations and deciding an optimal strategy for detecting this signal.

  9. Prospects for GMRT to Observe Radio Waves from UHE Particles Interacting with the Moon

    E-print Network

    Sukanta Panda; Subhendra Mohanty; Padmanabhan Janardhan; Oscar Stål

    2007-08-13

    Ultra high energy (UHE) particles of cosmic origin impact the lunar regolith and produce radio signals through Askaryan effect, signals that can be detected by Earth based radio telescopes. We calculate the expected sensitivity for observation of such events at the Giant Metrewave Radio Telescope (GMRT), both for UHE cosmic rays (CR) and UHE neutrino interactions. We find that for 30 days of observation time a significant number of detectable events is expected above $10^{20}$ eV for UHECR or neutrino fluxes close to the current limits. Null detection over a period of 30 days will lower the experimental bounds on UHE particle fluxes by magnitudes competitive to both present and future experiments at the very highest energies.

  10. The Dawn Topography Investigation

    NASA Technical Reports Server (NTRS)

    Raymond, C. A.; Jaumann, R.; Nathues, A.; Sierks, H.; Roatsch, T.; Preusker, E; Scholten, F.; Gaskell, R. W.; Jorda, L.; Keller, H.-U.; Zuber, M. T.; Smith, D. E.; Mastrodemos, N.; Mottola, S.

    2011-01-01

    The objective of the Dawn topography investigation is to derive the detailed shapes of 4 Vesta and 1 Ceres in order to create orthorectified image mosaics for geologic interpretation, as well as to study the asteroids' landforms, interior structure, and the processes that have modified their surfaces over geologic time. In this paper we describe our approaches for producing shape models, plans for acquiring the needed image data for Vesta, and the results of a numerical simulation of the Vesta mapping campaign that quantify the expected accuracy of our results. Multi-angle images obtained by Dawn's framing camera will be used to create topographic models with 100 m/pixel horizontal resolution and 10 m height accuracy at Vesta, and 200 m/pixel horizontal resolution and 20 m height accuracy at Ceres. Two different techniques, stereophotogrammetry and stereophotoclinometry, are employed to model the shape; these models will be merged with the asteroidal gravity fields obtained by Dawn to produce geodetically controlled topographic models for each body. The resulting digital topography models, together with the gravity data, will reveal the tectonic, volcanic and impact history of Vesta, and enable co-registration of data sets to determine Vesta's geologic history. At Ceres, the topography will likely reveal much about processes of surface modification as well as the internal structure and evolution of this dwarf planet.

  11. Profile measuring and topography modeling of aluminum alloy sheet surface

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Li, Zhigang

    2006-11-01

    With the development of lightweight vehicles, aluminum alloy sheet plays a more and more important role in auto panel production because of its high strength and low mass. However, aluminum alloy sheet is more difficult to forming than steel and its contact and friction behavior with the die surface in warm forming is more complicated. In order to study the laws of the contact and friction behavior, the topography data of aluminum alloy sheet surface should be obtained first so that the topography model can be set up. The authors introduce the principle and the performance of AF-LI Contact and Non-contact Synthesis Measuring Profilometer, get the topography data of aluminum alloy sheet surface by using contact measuring method. Then a statistical topography model of aluminum alloy sheet surface is set up based on the data.

  12. Hillslope glacier coupling: The interplay of topography and glacial dynamics in High Asia

    E-print Network

    Bookhagen, Bodo

    Hillslope glacier coupling: The interplay of topography and glacial dynamics in High Asia Dirk. Here we provide a regional synthesis of the topography and flow characteristics of 287 glaciers across High Asia using digital elevation analysis and remotely sensed glacier surface velocities. Glaciers

  13. Toward optical coherence topography

    NASA Astrophysics Data System (ADS)

    Sayegh, Samir; Jiang, Yanshui

    2012-03-01

    Commercial OCT systems provide pachymetry measurements. Full corneal topographic information of anterior and posterior corneal surfaces for use in cataract surgery and refractive procedures is a desirable goal and would add to the usefulness of anterior and posterior segment evaluation. While substantial progress has been made towards obtaining "average" central corneal power (D Huang), power in different meridians and topography are still missing. This is usually reported to be due to eye movement. We analyze the role of centration, eye movements and develop a model that allows for the formulation of criteria for obtaining reliable topographic data within ¼ diopter.

  14. RADAR Reveals Titan Topography

    NASA Technical Reports Server (NTRS)

    Kirk, R. L.; Callahan, P.; Seu, R.; Lorenz, R. D.; Paganelli, F.; Lopes, R.; Elachi, C.

    2005-01-01

    The Cassini Titan RADAR Mapper is a K(sub u)-band (13.78 GHz, lambda = 2.17 cm) linear polarized RADAR instrument capable of operating in synthetic aperture (SAR), scatterometer, altimeter and radiometer modes. During the first targeted flyby of Titan on 26 October, 2004 (referred to as Ta) observations were made in all modes. Evidence for topographic relief based on the Ta altimetry and SAR data are presented here. Additional SAR and altimetry observations are planned for the T3 encounter on 15 February, 2005, but have not been carried out at this writing. Results from the T3 encounter relevant to topography will be included in our presentation. Data obtained in the Ta encounter include a SAR image swath

  15. Topography of Io (color)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The images used to create this color composite of Io were acquired by Galileo during its ninth orbit (C9) of Jupiter and are part of a sequence of images designed to map the topography or relief on Io and to monitor changes in the surface color due to volcanic activity. Obtaining images at low illumination angles is like taking a picture from a high altitude around sunrise or sunset. Such lighting conditions emphasize the topography of the volcanic satellite. Several mountains up to a few miles high can be seen in this view, especially near the upper right. Some of these mountains appear to be tilted crustal blocks. Most of the dark spots correspond to active volcanic centers.

    North is to the top of the picture which merges images obtained with the clear, red, green, and violet filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. . The resolution is 8.3 kilometers per picture element. The image was taken on June 27, 1997 at a range of 817,000 kilometers by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  16. Improved foreground removal in GMRT 610 MHz observations towards redshifted 21-cm tomography

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhik; Bharadwaj, Somnath; Ali, Sk. Saiyad; Chengalur, Jayaram N.

    2011-12-01

    Foreground removal is a challenge for 21-cm tomography of the high-redshift Universe. We use archival Giant Metrewave Radio Telescope (GMRT) data (obtained for completely different astronomical goals) to estimate the foregrounds at a redshift of ˜1. The statistic we use is the cross power spectrum between two frequencies separated by ?? at the angular multipole ?, or equivalently the multi-frequency angular power spectrum C?(??). An earlier measurement of C?(??) using these data had revealed the presence of oscillatory patterns along ??, which turned out to be a severe impediment for foreground removal. Using the same data, in this paper we show that it is possible to considerably reduce these oscillations by suppressing the sidelobe response of the primary antenna elements. The suppression works best at the angular multipoles ? for which there is a dense sampling of the u-v plane. For three angular multipoles ?= 1405, 1602 and 1876, this sidelobe suppression along with a low order polynomial fitting completely results in residuals of (? 0.02 mK2), consistent with the noise at the 3? level. Since the polynomial fitting is done after estimation of the power spectrum it can be ensured that the estimation of the H I signal is not biased. The corresponding 99 per cent upper limit on the H I signal is ?, where ? is the mean neutral fraction and b is the bias.

  17. Brightest Cluster Galaxies in the Extended GMRT radio halo cluster sample. Radio properties and cluster dynamics

    E-print Network

    Kale, Ruta; Cassano, Rossella; Giacintucci, Simona; Bardelli, sandro; Dallacasa, Daniele; Zucca, Elena

    2015-01-01

    Brightest Cluster Galaxies (BCGs) show exceptional properties over the whole electromagnetic spectrum. Their special location at the centres of galaxy clusters raises the question of the role of the environment on their radio properties. To decouple the effect of the galaxy mass and of the environment in their statistical radio properties, we investigate the possible dependence of the occurrence of radio loudness and of the fractional radio luminosity function on the dynamical state of the hosting cluster. We studied the radio properties of the BCGs in the Extended GMRT Radio Halo Survey (EGRHS). We obtained a statistical sample of 59 BCGs, which was divided into two classes, depending on the dynamical state of the host cluster, i.e. merging (M) and relaxed (R). Among the 59 BCGs, 28 are radio-loud, and 31 are radio--quiet. The radio-loud sources are located favourably located in relaxed clusters (71\\%), while the reverse is true for the radio-quiet BCGs, mostly located in merging systems (81\\%). The fraction...

  18. Ocean Surface Topography Mission/ Jason 2 Launch

    E-print Network

    Ocean Surface Topography Mission/ Jason 2 Launch PreSS KiT/JUNe 2008 #12;#12;Media Contacts Steve .............................................................................................................................. 7 Why Study Ocean Surface Topography

  19. Topography of chance

    NASA Astrophysics Data System (ADS)

    Eliazar, Iddo I.; Cohen, Morrel H.

    2013-11-01

    We present a model of multiplicative Langevin dynamics that is based on two foundations: the Langevin equation and the notion of multiplicative evolution. The model is a nonlinear mechanism transforming a white-noise input to a dynamic-equilibrium output, using a single control: an underlying convex U-shaped potential function. The output is quantified by a stationary density which can attain a given number of shapes and a given number of randomness categories. The model generates each admissible combination of the output's shape and randomness in a universal and robust fashion. Moreover, practically all the probability distributions that are supported on the positive half-line, and that are commonly encountered and applied across the sciences, can be reverse engineered by this model. Hence, this model is a universal equilibrium mechanism, in the context of multiplicative dynamics, for the robust generation of “chance”: the model's output. In turn, the properties of the produced “chance,” the output's shape and randomness, are determined with mathematical precision by the control's landscape, its topography. Thus, a topographic map of chance is established. As a particular application, probability distributions with power-law tails are shown to be universally and robustly generated by controls on the “edge of convexity”: convex U-shaped potential functions with asymptotically linear wings.

  20. The GMRT High Resolution Southern Sky Survey for pulsars and transients -I. Survey description and initial discoveries

    E-print Network

    Bhattacharyya, Bhaswati; Malenta, Mateusz; Roy, Jayanta; Chengalur, Jayaram N; Keith, Michael; Kudale, Sanjay; McLaughlin, Maura; Ransom, Scott M; Ray, Paul S; Stappers, Benjamin W

    2015-01-01

    We are conducting a survey for pulsars and transients using the Giant Metrewave Radio Telescope (GMRT). The GMRT High Resolution Southern Sky (GHRSS) survey is an off-Galactic-plane (|b|>5) survey in the declination range -40 deg to -54 deg at 322 MHz. With the high time (up to 30.72 micro-sec) and frequency (up to 0.016275 MHz) resolution observing modes, the 5-sigma detection limit is 0.5 mJy for a 2 ms pulsar with 10% duty cycle at 322 MHz. Total GHRSS sky coverage of 2866 square-deg, will result from 1953 pointings, each covering 1.8 square-deg. The 10-sigma detection limit for a 5 ms transient burst is 1.6 Jy for the GHRSS survey. In addition, the GHRSS survey can reveal transient events like the rotating radio transients or the fast radio bursts. With 35% of the survey completed (i.e. 1000 square-deg), we report the discovery of 10 pulsars, one of which is a millisecond pulsar (MSP), this is one of the highest pulsar per square degree discovery rate for any off-Galactic plane survey. We re-detected 23 k...

  1. Deep GMRT 150 MHz observations of the LBDS-Lynx region: Ultra-Steep Spectrum Radio Sources

    E-print Network

    Ishwara-Chandra, C H; Wadadekar, Y; Pal, S; Windhorst, R

    2010-01-01

    It has been known for nearly three decades that high redshift radio galaxies exhibit steep radio spectra, and hence ultra-steep spectrum radio sources provide candidates for high-redshift radio galaxies. Nearly all radio galaxies with z > 3 have been found using this redshift-spectral index correlation. We have started a programme with GMRT to exploit this correlation at flux density levels about 10 to 100 times deeper than the known high-redshift radio galaxies which were identified primarily using the already available radio catalogues. In our programme, we have obtained deep, high resolution radio observations at 150 MHz with GMRT for several 'deep' fields which are well studied at higher radio frequencies and in other bands of the electromagnetic spectrum, with an aim to detect candidate high redshift radio galaxies. In this paper we present results from the deep 150 MHz observations of LBDS-Lynx field, which has been already imaged at 327, 610 and 1412 MHz with the WSRT and at 1400 and 4860 MHz with the ...

  2. Brightest cluster galaxies in the extended GMRT radio halo cluster sample. Radio properties and cluster dynamics

    NASA Astrophysics Data System (ADS)

    Kale, R.; Venturi, T.; Cassano, R.; Giacintucci, S.; Bardelli, S.; Dallacasa, D.; Zucca, E.

    2015-09-01

    Aims: First-ranked galaxies in clusters, usually referred to as brightest cluster galaxies (BCGs), show exceptional properties over the whole electromagnetic spectrum. They are the most massive elliptical galaxies and show the highest probability to be radio loud. Moreover, their special location at the centres of galaxy clusters raises the question of the role of the environment in shaping their radio properties. In the attempt to separate the effect of the galaxy mass and of the environment on their statistical radio properties, we investigate the possible dependence of the occurrence of radio loudness and of the fractional radio luminosity function on the dynamical state of the hosting cluster. Methods: We studied the radio properties of the BCGs in the Extended GMRT Radio Halo Survey (EGRHS), which consists of 65 clusters in the redshift range 0.2-0.4, with X-ray luminosity LX ? 5 × 1044 erg s-1, and quantitative information on their dynamical state from high-quality Chandra imaging. We obtained a statistical sample of 59 BCGs, which we divided into two classes, depending on whether the dynamical state of the host cluster was merging (M) or relaxed (R). Results: Of the 59 BCGs, 28 are radio loud and 31 are radio quiet. The radio-loud sources are favourably located in relaxed clusters (71%), while the reverse is true for the radio-quiet BCGs, which are mostly located in merging systems (81%). The fractional radio luminosity function for the BCGs in merging and relaxed clusters is different, and it is considerably higher for BCGs in relaxed clusters, where the total fraction of radio loudness reaches almost 90%, to be compared to the ~30% in merging clusters. For relaxed clusters, we found a positive correlation between the radio power of the BCGs and the strength of the cool core, consistent with previous studies on local samples. Conclusions: Our study suggests that the radio loudness of the BCGs strongly depends on the cluster dynamics; their fraction is considerably higher in relaxed clusters. We compare our results with similar investigations and briefly discuss them in the framework of AGN feedback.

  3. GMRT observation towards detecting the post-reionization 21-cm signal

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhik; Bharadwaj, Somnath; Ali, Sk. Saiyad; Chengalur, Jayaram N.

    2011-03-01

    The redshifted 21-cm signal from neutral hydrogen (H I) is an important future probe of the high-redshift Universe. We have analysed 610 MHz Giant Metrewave Radio Telescope (GMRT) observations towards detecting this signal from z= 1.32. The multi-frequency angular power spectrum C?(??) is used to characterize the statistical properties of the background radiation across angular scales ˜20 arcsec to 10 arcmin, and a frequency bandwidth of 7.5 MHz with resolution 125 kHz. The measured C?(??) which ranges from 7 to 18 mK2 is dominated by foregrounds, the expected H I signal CHI? (??) ˜ 10-6 to 10-7 mK2 is several orders of magnitude smaller and detecting this is a big challenge. The foregrounds, believed to originate from continuum sources, is expected to vary smoothly with ?? whereas the H I signal decorrelates within ˜0.5 MHz, and this holds the promise of separating the two. For each ?, we use the interval 0.5 ???? 7.5 MHz to fit a fourth-order polynomial which is subtracted from the measured C?(??) to remove any smoothly varying component across the entire bandwidth ??? 7.5 MHz. The residual C?(??), we find, has an oscillatory pattern with amplitude and period, respectively, ˜0.1 mK2 and ??= 3 MHz at the smallest ? value of 1476, and the amplitude and period decreasing with increasing ?. Applying a suitably chosen high pass filter, we are able to remove the residual oscillatory pattern for ?= 1476 where the residual C?(??) is now consistent with zero at the 3? noise level. Based on this we conclude that we have successfully removed the foregrounds at ?= 1476 and the residuals are consistent with noise. We use this to place an upper limit on the H I signal whose amplitude is determined by bar?H1b(CH1ell;(??)?[bar?H1b]2, where bar?H1 and b are the H I neutral fraction and the H I bias, respectively. A value of bar?H1b greater than 7.95 would have been detected in our observation, and is therefore ruled out at the 3? level. For comparison, studies of quasar absorption spectra indicate bar?H1 ? 2.5 × 10-2 which is ˜330 times smaller than our upper limit. We have not succeeded in completely removing the residual oscillatory pattern, whose cause is presently unknown to us, for the larger ? values.

  4. Nanoscale Surface Topography to Guide Bone Growth

    E-print Network

    Nanoscale Surface Topography to Guide Bone Growth P R O J E C T L E A D E R : Jirun Sun (American T S Designed and fabricated devices with nanoscale surface topography. Controlled cell alignment by varying

  5. Investigation of the solar UV/EUV heating effect on the Jovian radiation belt by GMRT-IRTF observation

    NASA Astrophysics Data System (ADS)

    Kita, H.; Misawa, H.; Bhardwaj, A.; Tsuchiya, F.; Tao, C.; Uno, T.; Kondo, T.; Morioka, A.

    2012-12-01

    Jupiter's synchrotron radiation (JSR) is the emission from relativistic electrons, and it is the most effective probe for remote sensing of Jupiter's radiation belt from the Earth. Recent intensive observations of JSR revealed short term variations of JSR with the time scale of days to weeks. Brice and McDonough (1973) proposed a scenario for the short term variations; i.e, the solar UV/EUV heating for Jupiter's upper atmosphere causes enhancement of total flux density. The purpose of this study is to investigate whether sufficient solar UV/EUV heating in Jupiter's upper atmosphere can actually causes variation in the JSR total flux and brightness distribution. Previous JSR observations using the Giant Metrewave Radio Telescope (GMRT) suggested important characteristics of short term variations; relatively low energy particles are accelerated by some acceleration processes which might be driven by solar UV/EUV heating and/or Jupiter's own magnetic activities. In order to evaluate the effect of solar UV/EUV heating on JSR variations, we made coordinated observations using the GMRT and NASA Infra-Red Telescope Facility (IRTF). By using IRTF, we can estimate the temperature of Jupiter's upper atmosphere from spectroscopic observation of H_3^+ infrared emission. Hence, we can evaluate the relationship between variations in Jupiter's upper atmosphere initiated by the solar UV/EUV heating and its linkage with the JSR. The GMRT observations were made during Nov. 6-17, 2011 at the frequency of 235/610MHz. The H_3^+ 3.953 micron line was observed using the IRTF during Nov. 7-12, 2011. During the observation period, the solar UV/EUV flux variations expected on Jupiter showed monotonic increase. A preliminary analysis of GMRT 610MHz band showed a radio flux variation similar to that in the solar UV/EUV. Radio images showed that the emission intensity increased at the outer region and the position of equatorial peak emission moved in the outward direction. If radial diffusion increases globally by the solar UV/EUV heating, it is expected that the peak intensity would increase and the peak position move inwards. However, our results are not consistent with the global enhancement of radial diffusion. In addition to that, the equatorial H_3^+ emission indicated that emission intensity decreased from the first day of observation to the last day. It is expected that equatorial temperature of Jupiter's atmosphere decreases during this observation period. Therefore, we propose that radial diffusion increased not globally but only at the outer region around L=2-3 during this period. From this hypothesis, it is expected that enhancement of radial diffusion at the outer region is caused by high latitude temperature enhancement. We discuss possible causes of the short term variations of JSR from the IRTF observation results at high latitude.

  6. Brain Topography, Volume 6, Number 1, 1993 79 Invertinga Laplacian TopographyMap

    E-print Network

    Klein, Stanley

    Brain Topography, Volume 6, Number 1, 1993 79 Invertinga Laplacian TopographyMap StanleyA. Klein. An Excel spreadsheet implementation of the algorithm is presented. Key words: Topography; Laplacian; Inverse laplacian;Principal components. Introduction Many researchers who measure the topography of evoked

  7. Mars Gravity and Topography Interpretations

    NASA Technical Reports Server (NTRS)

    Zuber, Maria T.; Smith, David E.; Solomon, Sean C.; Phillips, Roger J.

    1999-01-01

    New models of the topography of Mars and its gravity field from the Mars Global Surveyor mission are shedding new light on the structure of the planet and the state of isostatic compensation. Gravity field observations over the flat northern hemisphere plains show a number of anomalies at the 100 to 200 mGal level that have no apparent manifestation in the surface topography. We believe that these anomalies are probably the result of ancient impacts and represent regions of denser material buried beneath the outer depositional crust. Similar anomalies are also found in the region of the north polar ice cap even though a gravity anomaly resulting from the 3 km high icecap has not been uniquely identified. This leads us to speculate that the ice cap is largely compensated and is older than the timescale of isostatic compensation, about 10(exp 15) years.

  8. Topography, Cell Response, and Nerve Regeneration

    PubMed Central

    Hoffman-Kim, Diane; Mitchel, Jennifer A.; Bellamkonda, Ravi V.

    2010-01-01

    In the body, cells encounter a complex milieu of signals, including topographical cues. Imposed topography can affect cells on surfaces by promoting adhesion, spreading, alignment, morphological changes, and changes in gene expression. Neural response to topography is complex, and depends on the dimensions and shapes of physical features. Looking toward repair of nerve injuries, strategies are being explored to engineer guidance conduits with precise surface topographies. How neurons and other cell types sense and interpret topography remains to be fully elucidated. Studies reviewed here include those of topography on cellular organization and function as well as potential cellular mechanisms of response. PMID:20438370

  9. The Shuttle Radar Topography Mission

    NASA Astrophysics Data System (ADS)

    Farr, Tom G.; Rosen, Paul A.; Caro, Edward; Crippen, Robert; Duren, Riley; Hensley, Scott; Kobrick, Michael; Paller, Mimi; Rodriguez, Ernesto; Roth, Ladislav; Seal, David; Shaffer, Scott; Shimada, Joanne; Umland, Jeffrey; Werner, Marian; Oskin, Michael; Burbank, Douglas; Alsdorf, Douglas

    2007-06-01

    The Shuttle Radar Topography Mission produced the most complete, highest-resolution digital elevation model of the Earth. The project was a joint endeavor of NASA, the National Geospatial-Intelligence Agency, and the German and Italian Space Agencies and flew in February 2000. It used dual radar antennas to acquire interferometric radar data, processed to digital topographic data at 1 arc sec resolution. Details of the development, flight operations, data processing, and products are provided for users of this revolutionary data set.

  10. Earth rotation and core topography

    NASA Technical Reports Server (NTRS)

    Hager, Bradford H.; Clayton, Robert W.; Spieth, Mary Ann

    1988-01-01

    The NASA Geodynamics program has as one of its missions highly accurate monitoring of polar motion, including changes in length of day (LOD). These observations place fundamental constraints on processes occurring in the atmosphere, in the mantle, and in the core of the planet. Short-timescale (t less than or approx 1 yr) variations in LOD are mainly the result of interaction between the atmosphere and the solid earth, while variations in LOD on decade timescales result from the exchange of angular momentum between the mantle and the fluid core. One mechanism for this exchange of angular momentum is through topographic coupling between pressure variations associated with flow in the core interacting with topography at the core-mantel boundary (CMB). Work done under another NASA grant addressing the origin of long-wavelength geoid anomalies as well as evidence from seismology, resulted in several models of CMB topography. The purpose of work supported by NAG5-819 was to study further the problem of CMB topography, using geodesy, fluid mechanics, geomagnetics, and seismology. This is a final report.

  11. Landscape response to changes in dynamic topography

    NASA Astrophysics Data System (ADS)

    Ruetenik, Gregory A.; Moucha, Robert; Hoke, Gregory D.

    2015-04-01

    Dynamic topography is characterized by broad wavelength, low amplitude undulations of the Earth's surface maintained by stresses arising from mantle convection. Earth's topography is thus an aggregate of both dynamic and isostatic topography that is modulated by surface processes and changes in topography and/or the climate can be recorded in the offshore sedimentary record. However, it is generally difficult to deconvolve this record into contributions from changes in climate, isostatic topography, and dynamic topography. Herein, we use a landscape evolution model that is capable of producing simulations at the necessary scale and resolution for quantifying landscape response to moderate changes in dynamic topography in the presence of flexural unloading and loading due to erosion and deposition. We demonstrate that moderate changes in dynamic topography coupled with flexural response imposed on a landscape with pre-existing relief and drainage divide, disequilibrates the landscape resulting in a measurable increase in erosion rates and corresponding sedimentary flux to the margin. The magnitude and timing of this erosional response to dynamic topography is dependent on several key landscape evolution parameters, most notably the erosion (advection) coefficient and effective elastic thickness. Moreover, to maximize this response, we find that changes in dynamic topography must be slow enough and long-lived for given rates of erosion otherwise the landscape will not have sufficient time to generate a response. Lastly, this anomalous flux can persist for a significant amount of time beyond the influence of dynamic topography change as the landscape strives to re-equilibrate.

  12. GMRT Radio Halo Survey in galaxy clusters at z = 0.2 -- 0.4. II.The eBCS clusters and analysis of the complete sample

    E-print Network

    T. Venturi; S. Giacintucci; D. Dallacasa; R. Cassano; G. Brunetti; S. Bardelli; G. Setti

    2008-03-28

    We present the results of the GMRT cluster radio halo survey. The main purposes of our observational project are to measure which fraction of massive galaxy clusters in the redshift range z=0.2--0.4 hosts a radio halo, and to constrain the expectations of the particle re--acceleration model for the origin of the non--thermal radio emission. We selected a complete sample of 50 clusters in the X-ray band from the REFLEX (27) and the eBCS (23) catalogues. In this paper we present Giant Metrewave Radio Telescope (GMRT) observations at 610 MHz for all clusters still lacking high sensitivity radio information, i.e. 16 eBCS and 7 REFLEX clusters, thus completing the radio information for the whole sample. The typical sensitivity in our images is in the range 1$\\sigma \\sim 35-100 \\mu$Jy b$^{-1}$. We found a radio halo in A697, a diffuse peripheral source of unclear nature in A781, a core--halo source in Z7160, a candidate radio halo in A1682 and ``suspect'' central emission in Z2661. Including the literature information, a total of 10 clusters in the sample host a radio halo. A very important result of our work is that 25 out of the 34 clusters observed with the GMRT do not host extended central emission at the sensitivity level of our observations, and for 20 of them firm upper limits to the radio power of a giant radio halo were derived. The GMRT Radio Halo Survey shows that radio halos are not common, and our findings on the fraction of giant radio halos in massive clusters are consistent with the statistical expectations based on the re--acceleration model. Our results favour primary to secondary electron models.

  13. The Extended GMRT Radio Halo Survey. I. New upper limits on radio halos and mini-halos

    NASA Astrophysics Data System (ADS)

    Kale, R.; Venturi, T.; Giacintucci, S.; Dallacasa, D.; Cassano, R.; Brunetti, G.; Macario, G.; Athreya, R.

    2013-09-01

    Context. A fraction of galaxy clusters host diffuse radio sources called radio halos, radio relics and mini-halos. These are associated with the relativistic electrons and magnetic fields present on ~Mpc scales in the intra-cluster medium. Aims: We aim to carry out a systematic radio survey of all luminous galaxy clusters selected from the REFLEX and eBCS X-ray catalogues with the Giant Metrewave Radio Telescope, to understand the statistical properties of the diffuse radio emission in galaxy clusters. Methods: We present the sample and first results from the Extended GMRT Radio Halo Survey (EGRHS), which is an extension of the GMRT Radio Halo Survey (GRHS, Venturi et al. 2007, 2008). Analysis of radio data at 610/ 235/ 325 MHz on 12 galaxy clusters are presented. Results: We report the detection of a newly discovered mini-halo in the cluster RX J1532.9+3021 at 610 MHz. The presence of a small-scale relic (~200 kpc) is suspected in the cluster Z348. We do not detect cluster-scale diffuse emission in 11 clusters. Robust upper limits on the detection of radio halo of size of 1 Mpc are determined. We also present upper limits on the detections of mini-halos in a sub-sample of cool-core clusters. The upper limits for radio halos and mini-halos are plotted in the radio power- X-ray luminosity plane and the correlations are discussed. Diffuse extended emission that is not related to the target clusters, but detected as by-products in the sensitive images of two of the cluster fields (A689 and RX J0439.0+0715) is also reported. Conclusions: Based on the information about the presence of radio halos (or upper limits), available on 48 clusters out of the total sample of 67 clusters (EGRHS+GRHS), we find that 23 ± 7% of the clusters host radio halos. The radio halo fraction rises to 31 ± 11%, when only the clusters with X-ray luminosities >8 × 1044 erg s-1 are considered. Mini-halos are found in ~50% of cool-core clusters. A qualitative examination of the X-ray images of the clusters with no diffuse radio emission indicates that a majority of these clusters do not show extreme dynamical disturbances and supports the idea that mergers play an important role in generating radio halos and relics. The analysis of the full sample will be presented in a future work. Appendix A is available in electronic form at http://www.aanda.org

  14. Predicting channel bed topography in hydraulic falls

    NASA Astrophysics Data System (ADS)

    Tam, Alexander; Yu, Zheng; Kelso, Richard M.; Binder, Benjamin J.

    2015-11-01

    We consider inverse methods for predicting the channel bed topography in experiments of hydraulic falls. Nonlinear solutions and weakly nonlinear approximations from Euler-based models are compared to experimental observations. Accurate predictions are obtained for the maximum height of the topography and its constant horizontal level far downstream using the nonlinear method. The weakly nonlinear approximation is shown only to be a good predictor of the maximum height of the topography. The error in the inverse predictions is examined and discussed.

  15. Topography from single radar images.

    PubMed

    Wildey, R L

    1984-04-13

    A mathematical theory and a corresponding numerical procedure have been developed to produce digital topography from radar images as digital photometric arrays. Thus, as radargrammetry is to photogrammetry, so radarclinometry is to photoclinometry. Photoclinometry encompasses a fundamental indeterminacy principle even for terrain that is homogeneous in normal albedo, because the surface normal consistent with a given reflected specific intensity is not unique. A geometric locus of such normal directions is implied, which generates a surface. For microwave backscatter, in specific application to radarclinometry, this surface is a cone whose half-angle is the incidence angle, whose axis contains the radar, and whose apex coincides with the terrain point. Although the indeterminacy can be removed if a properly directed profile of ground truth is available as a constraint, such is seldom the case. In its absence, an auxiliary assumption, such as that the strike line runs perpendicular to the illumination line, is needed. If metric integrity is a goal, then this is an absurd assumption. Herein, "the hypothesis of local cylindricity" has been assumed, a premise regarding the nature of topographic curvature that seems more realistic and that makes possible the production of topography as a set of parallel line integrals. PMID:17744680

  16. Orbital and superorbital variability of LS I +61 303 at low radio frequencies with GMRT and LOFAR

    E-print Network

    Marcote, B; Paredes, J M; Ishwara-Chandra, C H; Swinbank, J D; Broderick, J W; Markoff, S; Fender, R; Wijers, R A M J; Pooley, G G; Stewart, A J; Bell, M E; Breton, R P; Carbone, D; Corbel, S; Eislöffel, J; Falcke, H; Grießmeier, J -M; Kuniyoshi, M; Pietka, M; Rowlinson, A; Serylak, M; van der Horst, A J; van Leeuwen, J; Wise, M W; Zarka, P

    2015-01-01

    LS I +61 303 is a gamma-ray binary that exhibits an outburst at GHz frequencies each orbital cycle of $\\approx$ 26.5 d and a superorbital modulation with a period of $\\approx$ 4.6 yr. We have performed a detailed study of the low-frequency radio emission of LS I +61 303 by analysing all the archival GMRT data at 150, 235 and 610 MHz, and conducting regular LOFAR observations within the Radio Sky Monitor (RSM) at 150 MHz. We have detected the source for the first time at 150 MHz, which is also the first detection of a gamma-ray binary at such a low frequency. We have obtained the light-curves of the source at 150, 235 and 610 MHz, all of them showing orbital modulation. The light-curves at 235 and 610 MHz also show the existence of superorbital variability. A comparison with contemporaneous 15-GHz data shows remarkable differences with these light-curves. At 15 GHz we see clear outbursts, whereas at low frequencies we see variability with wide maxima. The light-curve at 235 MHz seems to be anticorrelated with ...

  17. A High Galactic Latitude HI 21cm-line Absorption Survey using the GMRT: II. Results and Interpretation

    E-print Network

    Rekhesh Mohan; K. S. Dwarakanath; G. Srinivasan

    2004-10-26

    We have carried out a sensitive high-latitude (|b| > 15deg.) HI 21cm-line absorption survey towards 102 sources using the GMRT. With a 3-sigma detection limit in optical depth of ~0.01, this is the most sensitive HI absorption survey. We detected 126 absorption features most of which also have corresponding HI emission features in the Leiden Dwingeloo Survey of Galactic neutral Hydrogen. The histogram of random velocities of the absorption features is well-fit by two Gaussians centered at V(lsr) ~ 0 km/s with velocity dispersions of 7.6 +/- 0.3 km/s and 21 +/- 4 km/s respectively. About 20% of the HI absorption features form the larger velocity dispersion component. The HI absorption features forming the narrow Gaussian have a mean optical depth of 0.20 +/- 0.19, a mean HI column density of (1.46 +/- 1.03) X 10^{20} cm^{-2}, and a mean spin temperature of 121 +/- 69 K. These HI concentrations can be identified with the standard HI clouds in the cold neutral medium of the Galaxy. The HI absorption features forming the wider Gaussian have a mean optical depth of 0.04 +/- 0.02, a mean HI column density of (4.3 +/- 3.4) X 10^{19} cm^{-2}, and a mean spin temperature of 125 +/- 82 K. The HI column densities of these fast clouds decrease with their increasing random velocities. These fast clouds can be identified with a population of clouds detected so far only in optical absorption and in HI emission lines with a similar velocity dispersion. This population of fast clouds is likely to be in the lower Galactic Halo.

  18. Prospects for detection of the lunar Cerenkov emission by the UHE Cosmic Rays and Neutrinos using the GMRT and the Ooty Radio Telescope

    E-print Network

    Govind Swarup; Sukanta Panda

    2008-05-28

    Searching for the Ultra high energy Cosmic rays and Neutrinos of $> 10^{20} eV$ is of great cosmological importance. A powerful technique is to search for the \\v{C}erenkov radio emission caused by UHECR or UHE neutrinos impinging on the lunar regolith. We examine in this paper feasibility of detecting these events by observing with the Giant Metrewave Radio Telescope (GMRT) which has a large collecting area and operates over a wide frequency range with an orthogonal polarisation capability. We discuss here prospects of observations of the \\v{C}erenkov radio emission with the GMRT at 140 MHZ with 32 MHz bandwidth using the incoherent array and also forming 25 beams of the Central Array to cover the moon. We also consider using the Ooty Radio Telescope (ORT) which was specially designed in 1970 for tracking the Moon. With the ORT (530m long and 30m wide parabolic cylinder) it becomes possible to track the Moon for 9.5 hours on a given day by a simple rotation along the long axis of the parabolic cylinder. ORT operates at 325 MHz and has an effective collecting area of ~ 8000 $m^2.$ Recently a digital system has been installed by scientists of the Raman Research Institute (RRI), Bangalore and the Radio Astronomy Centre (RAC) of NCRA/TIFR, at Ooty allowing a bandwidth of 10 MHz with ~ 40 ns sampling. It is possible to form 6 beams covering the Moon and 7th beam far away for discrimination of any terrestrial RFI. Increasing the bandwidth of the existing 12 beam analogue system of the ORT from 4 MHz to 15 MHz to be sampled digitally is planned. It is shown that by observing the Moon for $\\ge$ 1000 hrs using the ORT it will provide appreciably higher sensitivity than past searches made elsewhere. Using the GMRT and ORT, it may be possible to reach sensitivity to test the Waxman-Bachall limit on UHE neutrino flux.

  19. Flat Subduction and Dynamic Topography

    NASA Astrophysics Data System (ADS)

    Lithgow-Bertelloni, C. R.; Dávila, F. M.; Eakin, C. M.; Crameri, F.

    2014-12-01

    Mantle dynamics manifests at the surface via the horizontal motions of plates and the vertical deflections that influence topography and the non-hydrostatic geoid. The pioneering work of Mitrovica et al. (1989) and Gurnis (1990) on this dynamic topography revolutionized our understanding of sedimentary basin formation, sea level changes and continental flooding. The temporal evolution of subduction can explain the migration of basins and even the drainage reversal of the Amazon (Shephard et al., 2012; Eakin et al., 2014). Until recently, flat subduction has been seen as enhancing downward deflection of the overriding plate and increasing flooding. However, this interpretation depends crucially on the details of the morphology and density structure of the slab, which controls the loci and amplitude of the deflection. We tend to ignore morphological details in mantle dynamics because flow can smooth out short wavelength variations. We have shown instead that details matter! Using South America as a natural laboratory because of the large changes in morphology of the Nazca slab along strike, we show that downward deflection of the overriding plate and hence basin formation, do not occur over flat segments but at the leading edge, where slabs plunge back into the mantle. This is true in both Argentina and Peru. The temporal evolution from a 'normally' dipplng slab to a flat slab leads to uplift over flat segments rather than enhanced subsidence. Critical for this result is the use of a detailed morphological model of the present-day Nazca slab with a spatial resolution of 50-100 km and based on relocated seismicity and magnetotelluric results. The density structure of the slab, due to age and the presence of overthickened crust from aseismic ridge subduction is essential. Overthickened crust leads to buoyant slabs. We reproduce formation and deposition of the Acres-Solimoes basin and the evolution of the Amazon drainage basin in Peru as well as the Mar Chiquita depression in Argentina. We explain the uplift of the paleosols of the los Llanos formation and the Fitzcarrald Arch. We show the effects of strong viscosity variations and slab dip on the extent of continental flooding.

  20. Topography and Landforms of Ecuador

    USGS Publications Warehouse

    Chirico, Peter G.; Warner, Michael B.

    2005-01-01

    EXPLANATION The digital elevation model of Ecuador represented in this data set was produced from over 40 individual tiles of elevation data from the Shuttle Radar Topography Mission (SRTM). Each tile was downloaded, converted from its native Height file format (.hgt), and imported into a geographic information system (GIS) for additional processing. Processing of the data included data gap filling, mosaicking, and re-projection of the tiles to form one single seamless digital elevation model. For 11 days in February of 2000, NASA, the National Geospatial-Intelligence Agency (NGA), the German Aerospace Center (DLR), and the Italian Space Agency (ASI) flew X-band and C-band radar interferometry onboard the Space Shuttle Endeavor. The mission covered the Earth between 60?N and 57?S and will provide interferometric digital elevation models (DEMs) of approximately 80% of the Earth's land mass when processing is complete. The radar-pointing angle was approximately 55? at scene center. Ascending and descending orbital passes generated multiple interferometric data scenes for nearly all areas. Up to eight passes of data were merged to form the final processed SRTM DEMs. The effect of merging scenes averages elevation values recorded in coincident scenes and reduces, but does not completely eliminate, the amount of area with layover and terrain shadow effects. The most significant form of data processing for the Ecuador DEM was gap-filling areas where the SRTM data contained a data void. These void areas are a result of radar shadow, layover, standing water, and other effects of terrain, as well as technical radar interferometry phase unwrapping issues. To fill these gaps, topographic contours were digitized from 1:50,000 - scale topographic maps which date from the mid-late 1980's (Souris, 2001). Digital contours were gridded to form elevation models for void areas and subsequently were merged with the SRTM data through GIS and remote sensing image-processing techniques. The data contained in this publication includes a gap filled, countrywide SRTM DEM of Ecuador projected in Universal Transverse Mercator (UTM) Zone 17 North projection, Provisional South American, 1956, Ecuador datum and a non gap filled SRTM DEM of the Galapagos Islands projected in UTM Zone 15 North projection. Both the Ecuador and Galapagos Islands DEMs are available as an ESRI Grid, stored as ArcInfo Export files (.e00), and in Erdas Imagine (IMG) file formats with a 90 meter pixel resolution. Also included in this publication are high and low resolution Adobe Acrobat (PDF) files of topography and landforms maps in Ecuador. The high resolution map should be used for printing and display, while the lower resolution map can be used for quick viewing and reference purposes.

  1. New CAM topography generation software

    NASA Astrophysics Data System (ADS)

    Lauritzen, P. H.; Bacmeister, J. T.; Taylor, M. A.; Neale, R. B.

    2012-12-01

    A new algorithm and associated software (to be released with NCAR's Community Atmosphere Model (CAM), version 5.2) to generate surface height and associated sub-grid-scale orographic variances is presented. The sub-grid-scale variance is separated into scales smaller than approximately 3km (referred to as SGH30), that is used for turbulent mountain stress parameterizations, and scales larger than approximately 3km and less than the model grid scale (referred to as SGH) used for gravity wave drag parameterizations. The raw topographic data is binned to an intermediate gnomonic cubed-sphere grid which, contrary to the older versions of CAM topography generation software, results in a quasi-isotropic separation of scales over the entire sphere for SGH30 and SGH. The cubed-sphere data is thereafter rigorously remapped using a volume conserving method to any target model grid. The algorithm supports structured and unstructured meshes; even meshes with non-convex control volumes. The new consistent specification of sub-grid-scale variances result in several improvements in `AMIP'-style climate simulations using CAM.

  2. Enhanced Characterization of Niobium Surface Topography

    SciTech Connect

    Chen Xu, Hui Tian, Charles Reece, Michael Kelley

    2011-12-01

    Surface topography characterization is a continuing issue for the Superconducting Radio Frequency (SRF) particle accelerator community. Efforts are underway to both to improve surface topography, and its characterization and analysis using various techniques. In measurement of topography, Power Spectral Density (PSD) is a promising method to quantify typical surface parameters and develop scale-specific interpretations. PSD can also be used to indicate how chemical processes modifiesy the roughnesstopography at different scales. However, generating an accurate and meaningful topographic PSD of an SRF surface requires careful analysis and optimization. In this report, polycrystalline surfaces with different process histories are sampled with AFM and stylus/white light interferometer profilometryers and analyzed to indicate trace topography evolution at different scales. evolving during etching or polishing. Moreover, Aan optimized PSD analysis protocol will be offered to serve the SRF surface characterization needs is presented.

  3. Scholte waves generated by seafloor topography

    E-print Network

    Zheng, Yingcai

    2012-01-01

    Seafloor topography can excite strong interface waves called Scholte waves that are often dispersive and characterized by slow propagation but large amplitude. This type of wave can be used to invert for near seafloor shear ...

  4. Corneal topography measurements for biometric applications

    NASA Astrophysics Data System (ADS)

    Lewis, Nathan D.

    The term biometrics is used to describe the process of analyzing biological and behavioral traits that are unique to an individual in order to confirm or determine his or her identity. Many biometric modalities are currently being researched and implemented including, fingerprints, hand and facial geometry, iris recognition, vein structure recognition, gait, voice recognition, etc... This project explores the possibility of using corneal topography measurements as a trait for biometric identification. Two new corneal topographers were developed for this study. The first was designed to function as an operator-free device that will allow a user to approach the device and have his or her corneal topography measured. Human subject topography data were collected with this device and compared to measurements made with the commercially available Keratron Piccolo topographer (Optikon, Rome, Italy). A third topographer that departs from the standard Placido disk technology allows for arbitrary pattern illumination through the use of LCD monitors. This topographer was built and tested to be used in future research studies. Topography data was collected from 59 subjects and modeled using Zernike polynomials, which provide for a simple method of compressing topography data and comparing one topographical measurement with a database for biometric identification. The data were analyzed to determine the biometric error rates associated with corneal topography measurements. Reasonably accurate results, between three to eight percent simultaneous false match and false non-match rates, were achieved.

  5. Geophysical implications of the longwavelength topography of Rhea

    E-print Network

    Nimmo, Francis

    Geophysical implications of the longwavelength topography of Rhea F. Nimmo,1 B. G. Bills,2 P. C 16 October 2010. [1] We use limb profiles to investigate the longwavelength topography topography of Rhea. The degree 3 topography is large enough, if uncompensated, to contaminate estimates

  6. Mantle transition zone topography and structure beneath the Yellowstone hotspot

    E-print Network

    Dueker, Ken

    Mantle transition zone topography and structure beneath the Yellowstone hotspot David Fee and Ken ± 1.6 km, with 36­40 km of peak to peak topography. This topography is spatially uncorrelated, providing no evidence for a lower mantle plume currently beneath the hotspot. The topography suggests

  7. Tidal Conversion by Supercritical Topography NEIL J. BALMFORTH

    E-print Network

    Balmforth, Neil

    Tidal Conversion by Supercritical Topography NEIL J. BALMFORTH University of British Columbia topography on the ocean floor. The ocean is treated as infinitely deep, and the topography consists. The calculations extend the previous results of Balmforth et al. for subcritical topography (wherein waves

  8. POLYGENETIC TOPOGRAPHY OF THE CASCADE RANGE, WASHINGTON STATE, USA

    E-print Network

    Montgomery, David R.

    POLYGENETIC TOPOGRAPHY OF THE CASCADE RANGE, WASHINGTON STATE, USA SARA GRAN MITCHELL Range of Washington State by analyzing the topography, geology, and exhumation patterns across the range-relief topography, 2) post-Miocene surface uplift of the range superimposed on pre-existing high-relief topography

  9. Topography of Mercury from Imaging Data

    NASA Astrophysics Data System (ADS)

    Gaskell, Robert W.; Gillis-Davis, J.; Sprague, A. L.

    2008-09-01

    During its January 2008 flyby of Mercury, the MESSENGER spacecraft acquired over 1200 MDIS images of the planet. Combined with images obtained during the three Mariner 10 flybys, well over half of Mercury's surface has now been imaged. We present preliminary results for the topography of that surface obtained by applying stereography and stereophotoclinometry (SPC) to the images. The technique generates a series of overlapping digital topography/albedo maps called L-maps which can be accurately aligned with each other, in images and on limbs. The L-map centers play the role of control points for the stereographic analysis, which solves for body-fixed control point location, camera pointing and spacecraft position. The L-maps themselves are determined by minimizing the brightness residuals between images and illuminated L-maps. The results must be treated as provisional because there was no significant variation in illumination during the flyby to help distinguish brightness variations due to topography from those due to albedo and because the useful stereo separation was less then 10°. Where there was overlap between the two imaging data sets, local illumination differed by close to 90 degrees, rather too large for the assumptions underlying SPC. We present both global topography for the surface imaged so far and local topography for areas of geological interest, including lobate scarps, vents and craters of interest.

  10. Electronic Cigarette Topography in the Natural Environment.

    PubMed

    Robinson, R J; Hensel, E C; Morabito, P N; Roundtree, K A

    2015-01-01

    This paper presents the results of a clinical, observational, descriptive study to quantify the use patterns of electronic cigarette users in their natural environment. Previously published work regarding puff topography has been widely indirect in nature, and qualitative rather than quantitative, with the exception of three studies conducted in a laboratory environment for limited amounts of time. The current study quantifies the variation in puffing behaviors among users as well as the variation for a given user throughout the course of a day. Puff topography characteristics computed for each puffing session by each subject include the number of subject puffs per puffing session, the mean puff duration per session, the mean puff flow rate per session, the mean puff volume per session, and the cumulative puff volume per session. The same puff topography characteristics are computed across all puffing sessions by each single subject and across all subjects in the study cohort. Results indicate significant inter-subject variability with regard to puffing topography, suggesting that a range of representative puffing topography patterns should be used to drive machine-puffed electronic cigarette aerosol evaluation systems. PMID:26053075

  11. Electronic Cigarette Topography in the Natural Environment

    PubMed Central

    Morabito, P. N.; Roundtree, K. A.

    2015-01-01

    This paper presents the results of a clinical, observational, descriptive study to quantify the use patterns of electronic cigarette users in their natural environment. Previously published work regarding puff topography has been widely indirect in nature, and qualitative rather than quantitative, with the exception of three studies conducted in a laboratory environment for limited amounts of time. The current study quantifies the variation in puffing behaviors among users as well as the variation for a given user throughout the course of a day. Puff topography characteristics computed for each puffing session by each subject include the number of subject puffs per puffing session, the mean puff duration per session, the mean puff flow rate per session, the mean puff volume per session, and the cumulative puff volume per session. The same puff topography characteristics are computed across all puffing sessions by each single subject and across all subjects in the study cohort. Results indicate significant inter-subject variability with regard to puffing topography, suggesting that a range of representative puffing topography patterns should be used to drive machine-puffed electronic cigarette aerosol evaluation systems. PMID:26053075

  12. Topography Restoration of Historic City Research

    NASA Astrophysics Data System (ADS)

    ho, L. Sung; soo, H. Dong

    2015-08-01

    The preservation of historic cities requires a balance between conservation and development because the urban structures of the old and new city are interwoven on same space. Existing restoration plans rely on old records and excavation reports and are based on the present topography. However, historic cities have undergone significant natural and anthropogenic topographic changes such as alluvial sediment accumulation and uneven terrain construction. Therefore, considering only the present topography is misleading. Thus, to understand a historic city's structure more appropriately, it is necessary to comprehend the ancient geographic environment. This study provides an analysis and GIS visualization of the ancient topography of a historic city, Sabi capital city of the Baekje Dynasty, which collapsed 1,500 years ago.

  13. Effects of patterned topography on biofilm formation

    NASA Astrophysics Data System (ADS)

    Vasudevan, Ravikumar

    2011-12-01

    Bacterial biofilms are a population of bacteria attached to each other and irreversibly to a surface, enclosed in a matrix of self-secreted polymers, among others polysaccharides, proteins, DNA. Biofilms cause persisting infections associated with implanted medical devices and hospital acquired (nosocomial) infections. Catheter-associated urinary tract infections (CAUTIs) are the most common type of nosocomial infections accounting for up to 40% of all hospital acquired infections. Several different strategies, including use of antibacterial agents and genetic cues, quorum sensing, have been adopted for inhibiting biofilm formation relevant to CAUTI surfaces. Each of these methods pertains to certain types of bacteria, processes and has shortcomings. Based on eukaryotic cell topography interaction studies and Ulva linza spore studies, topographical surfaces were suggested as a benign control method for biofilm formation. However, topographies tested so far have not included a systematic variation of size across basic topography shapes. In this study patterned topography was systematically varied in size and shape according to two approaches 1) confinement and 2) wetting. For the confinement approach, using scanning electron microscopy and confocal microscopy, orienting effects of tested topography based on staphylococcus aureus (s. aureus) (SH1000) and enterobacter cloacae (e. cloacae) (ATCC 700258) bacterial models were identified on features of up to 10 times the size of the bacterium. Psuedomonas aeruginosa (p. aeruginosa) (PAO1) did not show any orientational effects, under the test conditions. Another important factor in medical biofilms is the identification and quantification of phenotypic state which has not been discussed in the literature concerning bacteria topography characterizations. This was done based on antibiotic susceptibility evaluation and also based on gene expression analysis. Although orientational effects occur, phenotypically no difference was observed between the patterned topography tested. Another potential strategy for biofilm control through patterned topography is based on the design of robust non-wetting surfaces with undercut feature geometries, characterized by 1) breakthrough pressure and 2) triple phase contact line model. It was found that height and presence of undercut had statistically significant effects, directly proportional to breakthrough pressures, whereas extent of undercut did not. A predictive triple phase contact line model was also developed. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  14. Detecting and Quantifying Topography in Neural Maps

    PubMed Central

    Yarrow, Stuart; Razak, Khaleel A.; Seitz, Aaron R.; Seriès, Peggy

    2014-01-01

    Topographic maps are an often-encountered feature in the brains of many species, yet there are no standard, objective procedures for quantifying topography. Topographic maps are typically identified and described subjectively, but in cases where the scale of the map is close to the resolution limit of the measurement technique, identifying the presence of a topographic map can be a challenging subjective task. In such cases, an objective topography detection test would be advantageous. To address these issues, we assessed seven measures (Pearson distance correlation, Spearman distance correlation, Zrehen's measure, topographic product, topological correlation, path length and wiring length) by quantifying topography in three classes of cortical map model: linear, orientation-like, and clusters. We found that all but one of these measures were effective at detecting statistically significant topography even in weakly-ordered maps, based on simulated noisy measurements of neuronal selectivity and sparse sampling of the maps. We demonstrate the practical applicability of these measures by using them to examine the arrangement of spatial cue selectivity in pallid bat A1. This analysis shows that significantly topographic arrangements of interaural intensity difference and azimuth selectivity exist at the scale of individual binaural clusters. PMID:24505279

  15. Seasonally Flooded Hardwood Bottomlands Topography and Vegetation

    E-print Network

    Gray, Matthew

    plantings ­ Results? #12;Difficult at best to restore natural hydrology · River & Site Hydrology AlterationsSeasonally Flooded Hardwood Bottomlands #12;Topography and Vegetation Stream Channel Levee Back influence vegetation and animal communities) Surrounding land use is also important #12;Ridge and Swale

  16. Spherical Harmonic Models of Observed Dynamic Topography

    NASA Astrophysics Data System (ADS)

    Hoggard, M.; White, N. J.; Al-Attar, D.

    2014-12-01

    Mantle convective simulations are often used to predict present-day dynamic topography on Earth. Most of these models suggest that dynamic topography is dominated by degree 2 and 3 patterns which have peak amplitudes of 1-2 km. In order to test the applicability of these results, it is useful to construct an accurate global observational database. We have collated ~1000 seismic reflection profiles and ~500 wide-angle refraction experiments from the oceanic realm. This dataset can be used to calculate residual depth anomalies with respect to the well-known age-depth cooling relationship by carefully taking sedimentary and crustal loading effects into account. Resulting anomalies have wavelengths of 103-104 km with typical amplitudes of ±1 km. Average uncertainties are ±150 meters. We have combined these oceanic residual depths with onshore estimates from GRACE gravity anomalies to generate a spherical harmonic map of present-day dynamic topography. The resultant power spectrum is significantly less red than most predictive models. In other words, there is significantly less power at degrees 2 and 3 and much greater power at degrees 20 to 30 (i.e. wavelengths of 2000-1300 km). This mismatch implies that predictive models are currently compromised by limited resolution of mantle density structure and weak constraints on viscosity variation. Inclusion of accurate shallow mantle structure, which is the likely source of dynamic topography at degrees 20-30, is particularly important for future convective simulations.

  17. Localized Gravity/Topography Admittances on Mars

    NASA Technical Reports Server (NTRS)

    McGovern, Patrick J.; Solomon, Sean C.; Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Head, James W.

    2000-01-01

    Admittances from Mars Global Surveyor (MGS) gravity and topography yield estimates of lithosphere thickness on Mars: central Tharsis > 100 km, Alba Patera = 50 km, southern highlands < 20 km (but south polar cap > 50 km). Alba Patera and Elysium Rise are similar structures.

  18. Baroclinic Eddies Over Topography Claudia Cenedese

    E-print Network

    Dalziel, Stuart

    boundary in a rotating container. Different bottom topographies that simulate both a continental slope front and a gentle continental slope tended to stabilise this second instability while a continental and a continental ridge were introduced in the container and their presence modified the flow in comparison

  19. Sea bottom topography imaging with SAR

    NASA Technical Reports Server (NTRS)

    Vanderkooij, M. W. A.; Wensink, G. J.; Vogelzang, J.

    1992-01-01

    It is well known that under favorable meteorological and hydrodynamical conditions the bottom topography of shallow seas can be mapped with airborne or spaceborne imaging radar. This phenomenon was observed for the first time in 1969 by de Loor and co-workers in Q-band Side Looking Airborne Radar (SLAR) imagery of sandwaves in the North Sea. It is now generally accepted that the imaging mechanism consists of three steps: (1) interaction between (tidal) current and bottom topography causes spatial modulations in the surface current velocity; (2) modulations in the surface current velocity give rise to variations in the spectrum of wind-generated waves, as described by the action balance equation; and (3) variations in the wave spectrum show up as intensity modulations in radar imagery. In order to predict radar backscatter modulations caused by sandwaves, an imaging model, covering the three steps, was developed by the Dutch Sea Bottom Topography Group. This model and some model results will be shown. On 16 Aug. 1989 an experiment was performed with the polarimetric P-, L-, and C-band synthetic aperture radar (SAR) of NASA/JPL. One scene was recorded in SAR mode. On 12 Jul. 1991 another three scenes were recorded, of which one was in the ATI-mode (Along-Track Interferometer). These experiments took place in the test area of the Sea Bottom Topography Group, 30 km off the Dutch coast, where the bottom topography is dominated by sand waves. In-situ data were gathered by a ship in the test area and on 'Measuring Platform Noordwijk', 20 km from the center of the test area. The radar images made during the experiment were compared with digitized maps of the bottom. Furthermore, the profiles of radar backscatter modulation were compared with the results of the model. During the workshop some preliminary results of the ATI measurements will be shown.

  20. Links between climate, erosion, uplift, and topography during intracontinental mountain

    E-print Network

    Watts, A. B. "Tony"

    Links between climate, erosion, uplift, and topography during intracontinental mountain building a window into understanding how climate influences the erosion and resulting geomorphic and sedimentary signatures of continental topography. Specifically, asymmetric erosion of the Hangay, associated

  1. GRAVITY DRIVEN SHALLOW WATER MODELS FOR ARBITRARY TOPOGRAPHY

    E-print Network

    Blömker, Dirk

    GRAVITY DRIVEN SHALLOW WATER MODELS FOR ARBITRARY TOPOGRAPHY FRANC¸OIS BOUCHUT AND MICHAEL over a general topography. A first model is valid for small slope variation, i.e. small curvature, and a second model is valid for arbitrary topography. In both cases no particular assumption is made

  2. Towards Integrated Design of a Robust Feedback Controller and Topography

    E-print Network

    Van den Hof, Paul

    Towards Integrated Design of a Robust Feedback Controller and Topography Estimator for Atomic Force of the sample topography. Dynamical uncertainties of the system pose a strong limitation on the achievable control bandwidth, and on the accuracy of the estimated topography. This contribution discusses

  3. Long wave expansions for water waves over random topography

    E-print Network

    Craig, Walter

    Long wave expansions for water waves over random topography Anne de Bouard1 , Walter Craig2 interacting with the random bottom. We show that the resulting influence of the random topography is expressed numbers: 76B15, 35Q53, 76M50, 60F17 Keywords :Water waves, random topography, long wave asymptotics #12

  4. Generation of internal undular bores by transcritical flow over topography

    E-print Network

    Generation of internal undular bores by transcritical flow over topography R.H.J. Grimshaw1 , D. H, the interaction of a density stratified flow with topography can generate large-amplitude, horizontally. #12;Often, these waves are generated by critical flow over topography, and in this situation the waves

  5. Emergence of Topography and Complex Cell Properties from Natural Images

    E-print Network

    Hyvärinen, Aapo

    Emergence of Topography and Complex Cell Properties from Natural Images using Extensions of ICA complex cells. Second, we deøne a topography between the linear components obtained by ICA components are close to each other in the topography if they are strongly dependent on each other. This leads

  6. Topography of the merit function landscape in optical system design

    E-print Network

    Topography of the merit function landscape in optical system design Eco van Driel, Florian Bociort into the topography of merit function landscapes of arbitrary dimensionality. Keywords: global optimization, saddle the topography of the merit function space between them. Recently, we have shown that optimization paths

  7. RESEARCH ARTICLE Topography-mediated controls on local vegetation

    E-print Network

    Teskey, Robert O.

    RESEARCH ARTICLE Topography-mediated controls on local vegetation phenology estimated from MODIS patterns of phenology in humid temperate forest as a function of topography. Moderate-resolution imaging spectro- radiometer (MODIS) vegetation indices are used to derive local patterns of topography

  8. THE SIMILARITY-IN-TOPOGRAPHY PRINCIPLE: RECONCILING THEORIES OF CONCEPTUAL

    E-print Network

    Barsalou, Lawrence W.

    THE SIMILARITY-IN-TOPOGRAPHY PRINCIPLE: RECONCILING THEORIES OF CONCEPTUAL DEFICITS W. Kyle Simmons deficits, and offer different insights into their origins. Conceptual topography theory (CTT) integrates it with the similarity-in-topography (SIT) principle. According to CTT, feature maps in sensory-motor systems represent

  9. Coarsely resolved topography along protein folding pathways Ariel Fernandez

    E-print Network

    Berry, R. Stephen

    Coarsely resolved topography along protein folding pathways Ariel Ferna´ndez Instituto de Matema . The topography is represented as a sequence of minima and effective saddle points. The dominant folding pathway. Initially misfolded states form and dismantle revealing no definite pattern in the topography and exhibiting

  10. SLOPE DISTRIBUTIONS, THRESHOLD HILLSLOPES, AND STEADY-STATE TOPOGRAPHY

    E-print Network

    Montgomery, David R.

    SLOPE DISTRIBUTIONS, THRESHOLD HILLSLOPES, AND STEADY-STATE TOPOGRAPHY DAVID R. MONTGOMERY hillslopes, and steady-state topography. Plots of drainage area versus slope for these mountain ranges or exponential distributions in areas of active rock uplift and depositional topography, respectively. Local

  11. LONG WAVE EXPANSIONS FOR WATER WAVES OVER RANDOM TOPOGRAPHY

    E-print Network

    LONG WAVE EXPANSIONS FOR WATER WAVES OVER RANDOM TOPOGRAPHY ANNE DE BOUARD 1 , WALTER CRAIG 2 with the ran­ dom bottom. We show that the resulting influence of the random topography is expressed in terms of bottom topography a#ects the equations describing the limit of solutions in the long wave regime. We

  12. Timing and Topography of Nucleus Magnocellularis Innervation by the

    E-print Network

    Rubel, Edwin

    Timing and Topography of Nucleus Magnocellularis Innervation by the Cochlear Ganglion DAVID MOLEA). In the somatosensory system, for example, the topography of thalamocortical projections develops before the synaptic and Crowley, 2002). Thus, the common pattern of development seems to be that the topography of connections

  13. Surface Topography Quantification by Integral and Feature-related Parameters

    E-print Network

    Smid, Michiel

    Surface Topography Quantification by Integral and Feature-related Parameters Quantifizieren von microscopy, the topography of brittle fracture surfaces and wire- eroded surfaces was quantified. The global-related parameters in topographies, which uses methods of computational geometry. The software was tested using

  14. Diet and Dental Topography in Pitheciine Seed Predators

    E-print Network

    Boyer, Doug M.

    Diet and Dental Topography in Pitheciine Seed Predators Justin A. Ledogar,1 * Julia M. Winchester,2. Pitheciines also exhibit highly ``complex'' occlusal topography that promotes the effi- cient breakdown of demands imposed on the postcanine teeth of Pithecia might there- fore select for an average topography

  15. Stratified Flow over Topography: Wave Generation and Boundary Layer Separation

    E-print Network

    Sutherland, Bruce

    Stratified Flow over Topography: Wave Generation and Boundary Layer Separation B. R. Sutherland topography. We have chosen to use periodic, finite­amplitude hills which are representative of the Earth upon internal waves generated by flow over rough topography. 1 Introduction Internal waves propagate

  16. Stratified Flow over Topography: Wave Generation and Boundary Layer Separation

    E-print Network

    Sutherland, Bruce

    Stratified Flow over Topography: Wave Generation and Boundary Layer Separation B. R. Sutherland topography. We have chosen to use periodic, finite-amplitude hills which are representative of the Earth upon internal waves generated by flow over rough topography. 1 Introduction Internal waves propagate

  17. VALIDATION OF SPECTRAL UNMIXING METHODS USING PHOTOMETRY AND TOPOGRAPHY INFORMATION

    E-print Network

    Plaza, Antonio J.

    VALIDATION OF SPECTRAL UNMIXING METHODS USING PHOTOMETRY AND TOPOGRAPHY INFORMATION Rubén Marrero1 topography and photometry of the scene. The validation of the different methods and deconvolution processes topography and most importantly photometry are precisely known. On the other hand better distribution maps

  18. Diffraction imaging (topography) with monochromatic synchrotron radiation

    NASA Technical Reports Server (NTRS)

    Steiner, Bruce; Kuriyama, Masao; Dobbyn, Ronald C.; Laor, Uri

    1988-01-01

    Structural information of special interest to crystal growers and device physicists is now available from high resolution monochromatic synchrotron diffraction imaging (topography). In the review, the importance of superior resolution in momentum transfer and in space is described, and illustrations are taken from a variety of crystals: gallium arsenide, cadmium telluride, mercuric iodide, bismuth silicon oxide, and lithium niobate. The identification and understanding of local variations in crystal growth processes are shown. Finally, new experimental opportunities now available for exploitation are indicated.

  19. Mercury and Vesta - Preliminary shape and topography

    NASA Astrophysics Data System (ADS)

    Gaskell, R. W.; Palmer, E. E.; Mastrodemos, N.; Barnouin, O. S.; Jorda, L.; Taylor, A. H.

    2011-12-01

    This year two spacecraft, MESSENGER and Dawn, were placed into orbit around Mercury and the asteroid Vesta, respectively. We have been using stereophotoclinometry (SPC) to analyze MESSENGER and Dawn images both for navigation and to determine the precise shapes and topography of these bodies. Because SPC requires images at different local Sun elevations and azimuths to distinguish between albedo and topographic variations, Mercury presents the challenges of a slow spin rate and a long solar day. Vesta, on the other hand, rotates more than four times per Earth day, allowing a given area of surface to be viewed under rapidly changing illumination and topographic information to be built up rapidly. The essence of SPC is that small pieces of surface called maplets and modeled with digital elevation and albedo are illuminated and correlated with images. Hundreds of these maplets are found in each image, providing a valuable data type for spacecraft navigation. Hundreds of images go into the construction of each maplet, and the resulting multi-image stereo over a wide range of viewing conditions provides a precise determination of the maplet's body-fixed position. The construction of topography with SPC uses each pixel, allowing resolutions comparable to the images themselves. Mercury's topography varies by about 5 km above and below that of a sphere of radius 2440 km. We compare the SPC-derived shape and topography with data from MESSENGER's Mercury Laser Altimeter (MLA). Vesta, although a tenth of Mercury's size, exhibits variations in elevation between 17 km below and 12 km above the equipotential that best matches its surface. The lowest areas lie on the floor of the south polar impact crater, and the highest points lie on the crater's rim.

  20. Topography over South America from ERS altimetry

    NASA Technical Reports Server (NTRS)

    Brenner, Anita; Frey, Herb; DiMarzio, John; Tsaoussi, Lucia

    1997-01-01

    The results of the surface topography mapping of South America during the ERS-1 geodetic mission are presented. The altimeter waveforms, the range measurement, and the internal and Doppler range corrections were obtained. The atmospheric corrections and solid tides were calculated. Comparisons between Shuttle laser altimetry and ERS-1 altimetry grid showed good agreement. Satellite radar altimetry data can be used to improve the topographic knowledge of regions for which only poor elevation data currently exist.

  1. ATM Coastal Topography-Alabama 2001

    USGS Publications Warehouse

    Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Alabama coastline, acquired October 3-4, 2001. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative scanning Lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning Lidar system that measures high-resolution topography of the land surface, and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for pre-survey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography.

  2. ATM Coastal Topography-Mississippi, 2001

    USGS Publications Warehouse

    Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Mississippi coastline, from Lakeshore to Petit Bois Island, acquired September 9-10, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

  3. Global relationship between oceanic geoid and topography

    NASA Technical Reports Server (NTRS)

    Cazenave, A.; Dominh, K.; Allegre, C. J.; Marsh, J. G.

    1986-01-01

    The transfer function of geoid over topography as a function of wavelength is derived. The relationship between oceanic geoid and seafloor depth is analyzed. The correction of the geoid and topological data for thermal cooling of the oceanic lithosphere, sediment loading, and crustal thickening induced by volcanism under large ocean plateaus is discussed. The global residual depth and geoid anomalies are computed. The admittance and correlation between residual depth and geoid anomalies as a function of wavelength are examined.

  4. Solutions of barotropic trapped waves over topography

    NASA Astrophysics Data System (ADS)

    Zavala Sanson, Luis

    2010-05-01

    Solutions of free, barotropic waves over variable topography are derived. In particular, we examine two cases: waves around axisymmetric seamounts and waves along a sloping bottom. Even though these types of oscillations have been studied before, we revisit the problem because of two main reasons: (i) The linear, barotropic, shallow-water equations with a rigid lid are now solved with no further approximations, in contrast with previous studies. (ii) The solutions are applied to a wide family of seamounts and bottom slopes with profiles proportional to exp(rs) and ys, respectively, where r is the radial distance from the centre of the mountain, y is the direction perpendicular to the slope, and s is an arbitrary positive real number. Most of previous works on seamounts are restricted to the special case s = 2. By varying the shape parameter one can study trapped waves around flat-topped seamounts or guyots (s > 2) or sharp, cone-shaped topographies (s < 2). Similarly, most of previous studies on sloping bottoms report cases with s = 1 (linear slopes), whilst the present results are applied to more general bottom profiles. The resulting dispersion relation in both cases possess a remarkable simplicity that reveals a number of wave characteristics as a function of the topography shape.

  5. EAARL Topography-Padre Island National Seashore

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

    2007-01-01

    This Web site contains 116 Lidar-derived bare earth topography maps and GIS files for Padre Island National Seashore-Texas. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Florida Integrated Science Center (FISC) St. Petersburg, Florida, the National Park Service (NPS) Gulf Coast Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

  6. Optimizing HAPEX topography influences osteoblast response.

    PubMed

    Dalby, Matthew J; Di Silvio, Lucy; Gurav, Neelam; Annaz, Basil; Kayser, Michael V; Bonfield, William

    2002-07-01

    HAPEX (hydroxyapatite-reinforced polyethylene composite) is a second-generation orthopedic biomaterial designed as a bone analog material, which has found clinical success. The use of topography in cell engineering has been shown to affect cell attachment and subsequent response. Thus, by combining bioactivity and enhancing osteoblast response to the implant surface, improved tissue repair and implant life span may be achieved. In this study a primary human osteoblast-like cell model has been used to study the influence of surface topography and chemistry produced by three different production methods. Scanning electron microscopy, fluorescence microscopy, and confocal scanning laser microscopy have been used to study cell adhesion; tritiated thymidine uptake has been used to observe cell proliferation; and the reverse transcriptase-polymerase chain reaction and biochemical methods have been used to study phenotypic expression. Transmission electron microscopy has also been used to look at more long-term morphology. The results show that topography significantly influences cell response, and may be a means of enhancing bone apposition on HAPEX. PMID:12167231

  7. EAARL topography: George Washington Birthplace National Monument

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd

    2007-01-01

    This Web site contains Lidar-derived topography (first return and bare earth) maps and GIS files for George Washington Birthplace National Monument in Virginia. These lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, the National Park Service (NPS), Northeast Coastal and Barrier Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to coastal resource managers.

  8. Evolution of Neogene Dynamic Topography in Africa

    NASA Astrophysics Data System (ADS)

    Paul, Jonathan; Roberts, Gareth; White, Nicky

    2013-04-01

    The characteristic basins and swells of Africa's surface topography probably reflect patterns of convective circulation in the sub-lithospheric mantle. We have interrogated drainage networks to determine the spatial and temporal pattern of convectively driven uplift. ~560 longitudinal river profiles were extracted from a digital elevation model of Africa. An inverse model is then used to minimise the misfit between observed and calculated river profiles as a function of uplift rate history. During inversion, the residual misfit decreases from ~22 to ~5. Our results suggest that Africa's topography began to grow most rapidly after ~30 Ma at peak uplift rates of 0.1-0.15 mm/yr. The algorithm resolves distinct phases of uplift which generate localized swells of high topography and relief (e.g. the Angolan Dome). Uplift rate histories are shown to vary significantly from swell to swell. The calculated magnitudes, timing, and location of uplift agree well with local independent geological constraints, such as intense volcanism at Hoggar (42-39 Ma) and Afar (31-29 Ma), uplifted marine terraces, and warped peneplains. We have also calculated solid sediment flux histories for major African deltas which have persisted through time. This onshore record provides an important indirect constraint on the history of vertical motions at the surface, and agrees well with the offshore flux record, obtained from mapping isopachs of deltaic sediments. Our modelling and reconstructed sedimentary flux histories indicate that the evolution of drainage networks may contain useful information about mantle convective processes.

  9. OpenTopography: Enabling Online Access to High-Resolution Lidar Topography Data and Processing Tools

    NASA Astrophysics Data System (ADS)

    Crosby, Christopher; Nandigam, Viswanath; Baru, Chaitan; Arrowsmith, J. Ramon

    2013-04-01

    High-resolution topography data acquired with lidar (light detection and ranging) technology are revolutionizing the way we study the Earth's surface and overlying vegetation. These data, collected from airborne, tripod, or mobile-mounted scanners have emerged as a fundamental tool for research on topics ranging from earthquake hazards to hillslope processes. Lidar data provide a digital representation of the earth's surface at a resolution sufficient to appropriately capture the processes that contribute to landscape evolution. The U.S. National Science Foundation-funded OpenTopography Facility (http://www.opentopography.org) is a web-based system designed to democratize access to earth science-oriented lidar topography data. OpenTopography provides free, online access to lidar data in a number of forms, including the raw point cloud and associated geospatial-processing tools for customized analysis. The point cloud data are co-located with on-demand processing tools to generate digital elevation models, and derived products and visualizations which allow users to quickly access data in a format appropriate for their scientific application. The OpenTopography system is built using a service-oriented architecture (SOA) that leverages cyberinfrastructure resources at the San Diego Supercomputer Center at the University of California San Diego to allow users, regardless of expertise level, to access these massive lidar datasets and derived products for use in research and teaching. OpenTopography hosts over 500 billion lidar returns covering 85,000 km2. These data are all in the public domain and are provided by a variety of partners under joint agreements and memoranda of understanding with OpenTopography. Partners include national facilities such as the NSF-funded National Center for Airborne Lidar Mapping (NCALM), as well as non-governmental organizations and local, state, and federal agencies. OpenTopography has become a hub for high-resolution topography resources. Datasets hosted by other organizations, as well as lidar-specific software, can be registered into the OpenTopography catalog, providing users a "one-stop shop" for such information. With several thousand active users, OpenTopography is an excellent example of a mature Spatial Data Infrastructure system that is enabling access to challenging data for research, education and outreach. Ongoing OpenTopography design and development work includes the archive and publication of datasets using digital object identifiers (DOIs); creation of a more flexible and scalable high-performance environment for processing of large datasets; expanded support for satellite and terrestrial lidar; and creation of a "pluggable" infrastructure for third-party programs and algorithms. OpenTopography has successfully created a facility for sharing lidar data. In the project's next phase, we are working to enable equally easy and successful sharing of services for processing and analysis of these data.

  10. The topography of Iapetus' leading side

    NASA Astrophysics Data System (ADS)

    Giese, Bernd; Denk, Tilmann; Neukum, Gerhard; Roatsch, Thomas; Helfenstein, Paul; Thomas, Peter C.; Turtle, Elizabeth P.; McEwen, Alfred; Porco, Carolyn C.

    2008-02-01

    We have used Cassini stereo images to study the topography of Iapetus' leading side. A terrain model derived at resolutions of 4-8 km reveals that Iapetus has substantial topography with heights in the range of -10 km to +13 km, much more than observed on the other middle-sized satellites of Saturn so far. Most of the topography is older than 4 Ga [Neukum, G., Wagner, R., Denk, T., Porco, C.C., 2005. Lunar Planet. Sci. XXXVI. Abstract 2034] which implies that Iapetus must have had a thick lithosphere early in its history to support this topography. Models of lithospheric deflection by topographic loads provide an estimate of the required elastic thickness in the range of 50-100 km. Iapetus' prominent equatorial ridge [Porco, C.C., and 34 colleagues, 2005. Science 307, 1237-1242] reaches widths of 70 km and heights of up to 13 km from their base within the modeled area. The morphology of the ridge suggests an endogenous origin rather than a formation by collisional accretion of a ring remnant [Ip, W.-H., 2006. Geophys. Res. Lett. 33, doi: 10.1029/2005GL025386. L16203]. The transition from simple to complex central peak craters on Iapetus occurs at diameters of 11±3 km. The central peaks have pronounced conical shapes with flanking slopes of typically 11° and heights that can rise above the surrounding plains. Crater depths seem to be systematically lower on Iapetus than on similarly sized Rhea, which if true, may be related to more pronounced crater-wall slumping (which widens the craters) on Iapetus than on Rhea. There are seven large impact basins with complex morphologies including central peak massifs and terraced walls, the largest one reaches 800 km in diameter and has rim topography of up to 10 km. Generally, no rings are observed with the basins consistent with a thick lithosphere but still thin enough to allow for viscous relaxation of the basin floors, which is inferred from crater depth-to-diameter measurements. In particular, a 400-km basin shows up-domed floor topography which is suggestive of viscous relaxation. A model of complex crater formation with a viscoplastic (Bingham) rheology [Melosh, H.J., 1989. Impact Cratering. Oxford Univ. Press, New York] of the impact-shocked icy material provides an estimate of the effective cohesion/viscosity at 0.04±0.01 MPa/0.6±0.2 GPas. The local distribution of bright and dark material on the surface of Iapetus is largely controlled by topography and consistent with the dark material being a sublimation lag deposit originating from a bright icy substrate mixed with the dark components, but frost deposits are possible as well.

  11. Macromolecular Topography Leaps into the Digital Age

    NASA Technical Reports Server (NTRS)

    Lovelace, J.; Bellamy, H.; Snell, E. H.; Borgstahl, G.

    2003-01-01

    A low-cost, real-time digital topography system is under development which will replace x-ray film and nuclear emulsion plates. The imaging system is based on an inexpensive surveillance camera that offers a 1000x1000 array of 8 im square pixels, anti-blooming circuitry, and very quick read out. Currently, the system directly converts x-rays to an image with no phosphor. The system is small and light and can be easily adapted to work with other crystallographic equipment. Preliminary images have been acquired of cubic insulin at the NSLS x26c beam line. NSLS x26c was configured for unfocused monochromatic radiation. Six reflections were collected with stills spaced from 0.002 to 0.001 degrees apart across the entire oscillation range that the reflections were in diffracting condition. All of the reflections were rotated to the vertical to reduce Lorentz and beam related effects. This particular CCD is designed for short exposure applications (much less than 1 sec) and so has a relatively high dark current leading to noisy raw images. The images are processed to remove background and other system noise with a multi-step approach including the use of wavelets, histogram, and mean window filtering. After processing, animations were constructed with the corresponding reflection profile to show the diffraction of the crystal volume vs. the oscillation angle as well as composite images showing the parts of the crystal with the strongest diffraction for each reflection. The final goal is to correlate features seen in reflection profiles captured with fine phi slicing to those seen in the topography images. With this development macromolecular topography finally comes into the digital age.

  12. EAARL Coastal Topography - Sandy Hook 2007

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of Gateway National Recreation Area's Sandy Hook Unit in New Jersey, acquired on May 16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for pre-survey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  13. Welcome to Surface Topography: Metrology and Properties

    NASA Astrophysics Data System (ADS)

    Leach, Richard

    2013-11-01

    I am delighted to welcome readers to this inaugural issue of Surface Topography: Metrology and Properties (STMP). In these days of citation indexes and academic reviews, it is a tough, and maybe a brave, job to start a new journal. But the subject area has never been more active and we are seeing genuine breakthroughs in the use of surfaces to control functional performance. Most manufactured parts rely on some form of control of their surface characteristics. The surface is usually defined as that feature on a component or device, which interacts with either the environment in which it is housed (or in which the device operates), or with another surface. The surface topography and material characteristics of a part can affect how fluids interact with it, how the part looks and feels and how two bearing parts will slide together. The need to control, and hence measure, surface features is becoming increasingly important as we move into a miniaturized world. Surface features can become the dominant functional features of a part and may become large in comparison to the overall size of an object. Research into surface texture measurement and characterization has been carried out for over a century and is now more active than ever, especially as new areal surface texture specification standards begin to be introduced. The range of disciplines for which the function of a surface relates to its topography is very diverse; from metal sheet manufacturing to art restoration, from plastic electronics to forensics. Until now, there has been no obvious publishing venue to bring together all these applications with the underlying research and theory, or to unite those working in academia with engineering and industry. Hence the creation of Surface Topography: Metrology and Properties . STMP will publish the best work being done across this broad discipline in one journal, helping researchers to share common themes and highlighting and promoting the extraordinary benefits this field yields across an array of applications in the modern world. To this end, we have gathered leading experts from across our scope to form our inaugural editorial board. Their broad subject knowledge and experience will help to guide the journal and ensure we meet our goal of high-quality research, published quickly, across the breadth of the subject. We are committed to providing a rapid and yet rigorous peer review process. As a launch promotion, all STMP's published content will be free to readers during 2013. The editorial board and I hope you will be as excited by the possibilities of this new journal as we are, and that you will choose to both submit your research and read STMP in the months and years to come. We look forward to reading your papers!

  14. Carbon contamination topography analysis of EUV masks

    SciTech Connect

    Fan, Y.-J.; Yankulin, L.; Thomas, P.; Mbanaso, C.; Antohe, A.; Garg, R.; Wang, Y.; Murray, T.; Wuest, A.; Goodwin, F.; Huh, S.; Cordes, A.; Naulleau, P.; Goldberg, K. A.; Mochi, I.; Gullikson, E.; Denbeaux, G.

    2010-03-12

    The impact of carbon contamination on extreme ultraviolet (EUV) masks is significant due to throughput loss and potential effects on imaging performance. Current carbon contamination research primarily focuses on the lifetime of the multilayer surfaces, determined by reflectivity loss and reduced throughput in EUV exposure tools. However, contamination on patterned EUV masks can cause additional effects on absorbing features and the printed images, as well as impacting the efficiency of cleaning process. In this work, several different techniques were used to determine possible contamination topography. Lithographic simulations were also performed and the results compared with the experimental data.

  15. GMRT Radio Halo Survey in galaxy clusters at z = 0.2 -- 0.4 I.The REFLEX sub--sample

    E-print Network

    T. Venturi; S. Giacintucci; G. Brunetti; R. Cassano; S. Bardelli; D. Dallacasa; G. Setti

    2006-12-02

    Aims. We present the first results of an ongoing project devoted to the search of giant radio halos in galaxy clusters located in the redshift range z=0.2--0.4. One of the main goals of our study is to measure the fraction of massive galaxy clusters in this redshift interval hosting a radio halo, and to constrain the expectations of the particle re--acceleration model for the origin of non--thermal radio emission in galaxy clusters. Methods. We selected 27 REFLEX clusters and here we present Giant Metrewave Radio Telescope (GMRT) observations at 610 MHz for 11 of them. The sensitivity (1$\\sigma$) in our images is in the range 35--100~$\\mu$Jy beam$^{-1}$ for all clusters. Results. We found three new radio halos, doubling the number of halos known in the selected sample. In particular, giant radio halos were found in A 209 and RXCJ 2003.5--2323, and one halo (of smaller size) was found in RXCJ 1314.4--2515. Candidate extended emission on smaller scale was found around the central galaxy in A 3444 which deserves further investigation. Furthermore, a radio relic was found in A 521, and two relics were found in RXCJ 1314.5--2515. The remaining six clusters observed do not host extended emission of any kind.

  16. New insights into the evolution of the FR I radio galaxy 3C 270 (NGC 4261) from VLA and GMRT radio observations

    E-print Network

    Kolokythas, Konstantinos; Giacintucci, Simona; Raychaudhury, Somak; Ishwara-Chandra, C H; Worrall, Diana M; Birkinshaw, Mark

    2015-01-01

    We present Giant Metrewave Radio Telescope (GMRT) 240 MHz observations of the nearby luminous FR I radio source 3C 270, in the group-central elliptical NGC 4261. Combining these data with reprocessed Very Large Array (VLA) 1.55 and 4.8 GHz observations, we produce spectral index maps that reveal a constant spectral index along the jets and a gradual steepening from the ends of the jets through the lobes towards the nucleus. A Jaffe & Perola (JP) model fitted to the integrated spectrum of the source gives an asymptotic low-frequency index of $\\alpha_{inj}=0.53_{-0.02}^{+0.01}$, while JP models fitted to the observed spectral index trend along the lobes allow us to estimate radiative ages of $\\sim29$ Myr and $\\sim37$ Myr for the west and east lobes respectively. Our age estimates are a factor of two lower than the 75-Myr upper limit derived from X-ray data (O'Sullivan et al. 2011). We find unlikely the scenario of an early supersonic phase in which the lobe expanded into the ISM at approximately Mach 6 (350...

  17. Support of long-wavelength topography on Mercury inferred from MESSENGER measurements of gravity and topography

    NASA Astrophysics Data System (ADS)

    James, Peter B.; Zuber, Maria T.; Phillips, Roger J.; Solomon, Sean C.

    2015-02-01

    To explore the mechanisms of support of surface topography on Mercury, we have determined the admittances and correlations of topography and gravity in Mercury's northern hemisphere from measurements obtained by NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. These admittances and correlations can be interpreted in the context of a number of theoretical scenarios, including flexural loading and dynamic flow. We find that long-wavelength (spherical harmonic degree l < 15) surface topography on Mercury is primarily supported through a combination of crustal thickness variations and deep mass anomalies. The deep mass anomalies may be interpreted either as lateral variations in mantle density or as relief on compositional interfaces. Domical topographic swells are associated with high admittances and are compensated at 300-400 km depth in the lower reaches of Mercury's mantle. Quasi-linear topographic rises are primarily associated with shallow crustal compensation and are weakly correlated with positive mass anomalies in the mantle. The center of the Caloris basin features some of the thinnest crust on the planet, and the basin is underlain by a large negative mass anomaly. We also explore models of dynamic flow in the presence of compositional stratification above the liquid core. If there is substantial compositional stratification in Mercury's solid outer shell, relaxation of perturbed compositional interfaces may be capable of creating and sustaining long-wavelength topography.

  18. Gravity/Topography Admittances and Lithospheric Evolution on Mars: The Importance of Finite-Amplitude Topography

    NASA Technical Reports Server (NTRS)

    McGovern, Patrick J.; Solomon, Sean C.; Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Head, J. W., III; Phillips, Roger J.; Simons, Mark

    2001-01-01

    We calculate localized gravity/topography admittances for Mars, in order to estimate elastic lithosphere thickness. A finite-amplitude correction to modeled gravity is required to properly interpret admittances in high-relief regions of Mars. Additional information is contained in the original extended abstract.

  19. Dynamic Topography at Earth's Surface: Fact or Fiction? (Invited)

    NASA Astrophysics Data System (ADS)

    Lithgow-Bertelloni, C. R.; Silver, P. G.

    2009-12-01

    Contributions to Earth’s surface topography range from short-wavelength uncompensated features due to tectonic activity, to variations in crustal structure and long-wavelength deflections of the lithosphere caused by mantle dynamics. The latter we call dynamic topography. Dynamic topography elevates or depresses the surface even if the density anomaly giving rise to flow is deep in the mantle. Dynamic topography is also a major contributor to Earth’s gravitational potential and to surface deformation. However, direct observations of dynamic topography are elusive, because signals are obscured by the isostatic contribution due to crustal and lithospheric structure. The only seemingly unequivocal signals of dynamically supported topography have been found over mantle upwellings on both continents (Africa [Lithgow-Bertelloni and Silver, 1998] and Arabia [Daradich et al., 2004]) and oceanic basins (North-Atlantic [Conrad et al., 2004]). Recent work on Africa’s geomorphic history [Moore et al., 2009] and North Atlantic gravity and topography have called even these results into questions. In downwelling regions (near slabs) no clear signals have been found. I will explore why this dichotomy may exist and relate it to the need for dynamic topography in mantle flow models, with an eye towards the effects of phase transitions, lateral variations in viscosity and layered convection. I will also present recent results on dynamic topography over flat slab segments that overturn the conventional wisdom and explain basin topography in the Andean foreland. Along with the new models I will discuss a recent global lithospheric structure model with which to compute the residual topography, i.e. the “observed” dynamic topography.

  20. Retrieving lunar topography from multispectral LROC images

    NASA Astrophysics Data System (ADS)

    Korokhin, Viktor V.; Velikodsky, Yuri I.; Shalygin, Eugene V.; Shkuratov, Yuriy G.; Kaydash, Vadym G.; Videen, Gorden

    2014-03-01

    A technique for retrieving information about the lunar topography from any individual multispectral LROC Wide Angle Camera (WAC) image has been developed. This technology is possible, since images acquired at different wavelengths correspond to different viewing angles and the influence of color differences between the images on the parallax assessments is small. This method provides the precision of Digital Elevation Models (DEMs) comparable to the global lunar 100 m raster DTM retrieved from the LROC WAC stereo model (GLD100). It potentially allows one to obtain maps of the elevations with better horizontal resolution than those of the GLD100. An empirical model of the distortion for LROC WAC has been developed and used for correction of the initial WAC images. In contrast to the standard pre-flight model, our model allows for compensation of the radial distortion, decentering the optics, and tilt of the CCD array almost fully. The DEMs obtained using our approach exhibit real morphological details in some cases that are invisible in GLD100 maps. Thus, our method suggests additional independent information about the lunar topography. The fact that our elevation maps have the same projection as the initial images allows valid corrections of these images to account for topographic effects (i. e. orthorectification) in contrast to the use of the GLD100 that may have slightly different coordinates referencing in comparison to individual WAC images.

  1. Uncertainty in measurement of surface topography

    NASA Astrophysics Data System (ADS)

    Haitjema, Han

    2015-09-01

    The 2.5-dimensional (2.5D) roughness parameters were standardized in 2012. With their increasing use in science and industry, the request for traceability and uncertainty evaluation for these parameters follows logically. This paper gives an overview of the problems and possibilities that appear when uncertainties have to be associated with values that are derived from a measured surface topography, such as the Ra-value of a periodic specimen, the RSm value of a type-D standard, and the Sa-value of a single cutoff length of a type D standard. It is shown that straightforward implementation of the methods described in the ‘Guide to the Expression of Uncertainty in Measurement’ (GUM) leads to impossible and impracticable equations because of the correlations between some millions of measurement points. A practical solution is found by considering the main aspects of uncertainty, as these are given in the recent ISO 25178 standards series, and applying these to a measured surface topography as a whole.

  2. EAARL Topography-Colonial National Historical Park

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Stevens, Sara; Travers, Laurinda J.

    2008-01-01

    These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, Florida Integrated Science Center (FISC) St. Petersburg, the National Park Service (NPS) Inventory and Monitoring Program, Northeast Coastal and Barrier Network, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs, barrier islands, and various nearshore coastal environments for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to coastal resource managers.

  3. Origin of bending in uncoated microcantilever - Surface topography?

    SciTech Connect

    Lakshmoji, K.; Prabakar, K.; Tripura Sundari, S. Jayapandian, J.; Tyagi, A. K.; Sundar, C. S.

    2014-01-27

    We provide direct experimental evidence to show that difference in surface topography on opposite sides of an uncoated microcantilever induces bending, upon exposure to water molecules. Examination on opposite sides of the microcantilever by atomic force microscopy reveals the presence of localized surface features on one side, which renders the induced stress non-uniform. Further, the root mean square inclination angle characterizing the surface topography shows a difference of 73° between the opposite sides. The absence of deflection in another uncoated microcantilever having similar surface topography confirms that in former microcantilever bending is indeed induced by differences in surface topography.

  4. EAARL Coastal Topography - Northern Gulf of Mexico

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Sallenger, Abby; Wright, C. Wayne; Travers, Laurinda J.; Lebonitte, James

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived coastal topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. One objective of this research is to create techniques to survey areas for the purposes of geomorphic change studies following major storm events. The USGS Coastal and Marine Geology Program's National Assessment of Coastal Change Hazards project is a multi-year undertaking to identify and quantify the vulnerability of U.S. shorelines to coastal change hazards such as effects of severe storms, sea-level rise, and shoreline erosion and retreat. Airborne Lidar surveys conducted during periods of calm weather are compared to surveys collected following extreme storms in order to quantify the resulting coastal change. Other applications of high-resolution topography include habitat mapping, ecological monitoring, volumetric change detection, and event assessment. The purpose of this project is to provide highly detailed and accurate datasets of the northern Gulf of Mexico coastal areas, acquired on September 19, 2004, immediately following Hurricane Ivan. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Airborne Advanced Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532 nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking RGB (red-green-blue) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system on September 19, 2004. The survey resulted in the acquisition of 3.2 gigabytes of data. The data were processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for pre-survey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of 'last return' elevations.

  5. Topographies of forensic practice in Imperial Germany.

    PubMed

    Engstrom, Eric J

    2014-01-01

    This article examines the topography and "cultural machinery" of forensic jurisdictions in Imperial Germany. It locates the sites at which boundary disputes between psychiatric and legal professionals arose and explores the strategies and practices that governed the division of expert labor between them. It argues that the over-determined paradigms of 'medicalization' and 'biologization' have lost much of their explanatory force and that historians need to refocus their attention on the institutional and administrative configuration of forensic practices in Germany. After first sketching the statutory context of those practices, the article explores how contentious jurisdictional negotiations pitted various administrative, financial, public security, and scientific interests against one another. The article also assesses the contested status of psychiatric expertise in the courtroom, as well as post-graduate forensic psychiatric training courses and joint professional organizations, which drew the two professional communities closer together and mediated their jurisdictional disputes. PMID:24125958

  6. Mean Dynamic Topography of the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Farrell, Sinead Louise; Mcadoo, David C.; Laxon, Seymour W.; Zwally, H. Jay; Yi, Donghui; Ridout, Andy; Giles, Katherine

    2012-01-01

    ICESat and Envisat altimetry data provide measurements of the instantaneous sea surface height (SSH) across the Arctic Ocean, using lead and open water elevation within the sea ice pack. First, these data were used to derive two independent mean sea surface (MSS) models by stacking and averaging along-track SSH profiles gathered between 2003 and 2009. The ICESat and Envisat MSS data were combined to construct the high-resolution ICEn MSS. Second, we estimate the 5.5-year mean dynamic topography (MDT) of the Arctic Ocean by differencing the ICEn MSS with the new GOCO02S geoid model, derived from GRACE and GOCE gravity. Using these satellite-only data we map the major features of Arctic Ocean dynamical height that are consistent with in situ observations, including the topographical highs and lows of the Beaufort and Greenland Gyres, respectively. Smaller-scale MDT structures remain largely unresolved due to uncertainties in the geoid at short wavelengths.

  7. Australian topography from Seasat overland altimetry

    NASA Technical Reports Server (NTRS)

    Frey, Herbert; Brenner, Anita C.

    1990-01-01

    Retracking of overland returns from the Seasat altimeter using algorithms originally developed for recovering elevations over ice has led to the successful recovery of high quality continental topography over Australia and other continents. Cross-over analysis both before and after orbit adjustment shows the altimetric data over land to have a 2-3 m quality. Direct comparison of gridded Seasat data with surface data re-averaged in the same way shows excellent agreement except where Seasat data are sparse, due either to poor track spacing or to dropouts caused by loss of tracker lock over steeply sloping ground. These results suggest that useful topographic data can be derived from Seasat and the more recent Geosat altimeters for parts of the world where surface data are few or of poor quality.

  8. EAARL topography: Dry Tortugas National Park

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd

    2008-01-01

    This lidar-derived submarine topography map was produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs for the purposes of habitat mapping, ecological monitoring, change detection, ad event assessment (for example: bleaching, hurricanes, disease outbreaks). As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring water depth and conducting cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to managers of coastal tropical habitats.

  9. Surface Water and Ocean Topography (SWOT) mission

    NASA Astrophysics Data System (ADS)

    Neeck, Steven P.; Lindstrom, Eric J.; Vaze, Parag V.; Fu, Lee-Lueng

    2012-09-01

    The Surface Water Ocean Topography (SWOT) mission was recommended in 2007 by the National Research Council's Decadal Survey, "Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond", for implementation by NASA. The SWOT mission is a partnership between two communities, the physical oceanography and the hydrology, to share high vertical accuracy and high spatial resolution topography data produced by the science payload, principally a Ka-band radar Interferometer (KaRIn). The SWOT payload also includes a precision orbit determination system consisting of GPS and DORIS receivers, a Laser Retro-reflector Assembly (LRA), a Jason-class nadir radar altimeter, and a JASON-class radiometer for tropospheric path delay corrections. The SWOT mission will provide large-scale data sets of ocean sea-surface height resolving scales of 15km and larger, allowing the characterization of ocean mesoscale and submesoscale circulation. The SWOT mission will also provide measurements of water storage changes in terrestrial surface water bodies and estimates of discharge in large (wider than 100m) rivers globally. The SWOT measurements will provide a key complement to other NASA spaceborne global measurements of the water cycle measurements by directly measuring the surface water (lakes, reservoirs, rivers, and wetlands) component of the water cycle. The SWOT mission is an international partnership between NASA and the Centre National d'Etudes Spatiales (CNES). The Canadian Space Agency (CSA) is also expected to contribute to the mission. SWOT is currently nearing entry to Formulation (Phase A). Its launch is targeted for October 2020.

  10. Evolution of Neogene Dynamic Topography in Madagascar

    NASA Astrophysics Data System (ADS)

    Paul, J. D.; Roberts, G.; White, N. J.

    2012-12-01

    Madagascar is located on the fringes of the African superswell. Its position and the existence of a +30 mGal long wavelength free-air gravity anomaly suggest that its present-day topography is maintained by convective circulation of the sub-lithospheric mantle. Residual depth anomalies of oceanic crust encompassing the island imply that Madagascar straddles a dynamic topographic gradient. In June-July 2012, we examined geologic evidence for Neogene uplift around the Malagasy coastline. Uplifted coral reef deposits, fossil beach rock, and terraces demonstrate that the northern and southern coasts are probably being uplifted at a rate of ~0.2 mm/yr. Rates of uplift clearly vary around the coastline. Inland, extensive peneplains occur at elevations of 1 - 2 km. These peneplains are underlain by 10 - 20 m thick laterite deposits, and there is abundant evidence for rapid erosion (e.g. lavaka). Basaltic volcanism also occurred during Neogene times. These field observations can be combined with an analysis of drainage networks to determine the spatial and temporal pattern of convectively driven uplift. ~100 longitudinal river profiles were extracted from a digital elevation model of Madagascar. An inverse model is then used to minimize the misfit between observed and calculated river profiles as a function of uplift rate history. During inversion, the residual misfit decreases from ~20 to ~4. Our results suggest that youthful and rapid uplift of 1-2 km occurred at rates of 0.2-0.4 mm/yr during the last ˜15 Myr. The algorithm resolves distinct phases of uplift which generate localized swells of high topography and relief (e.g. the Hauts Plateaux). Our field observations and modeling indicate that the evolution of drainage networks may contain useful information about mantle convective processes.

  11. Cokriging surface elevation and seismic refraction data for bedrock topography

    SciTech Connect

    Nyquist, J.E.; Doll, W.E. ); Davis, R.K. ); Hopkins, R.A. )

    1992-01-01

    Analysis of seismic refraction data collected at a proposed site of the Advanced Neutron Source (ANS) Facility showed a strong correlation between surface and bedrock topography. By combining seismically determined bedrock elevation data with surface elevation data using cokriging, we were able to significantly improve our map of bedrock topography without collecting additional seismic data.

  12. Cokriging surface elevation and seismic refraction data for bedrock topography

    SciTech Connect

    Nyquist, J.E.; Doll, W.E.; Davis, R.K.; Hopkins, R.A.

    1992-11-01

    Analysis of seismic refraction data collected at a proposed site of the Advanced Neutron Source (ANS) Facility showed a strong correlation between surface and bedrock topography. By combining seismically determined bedrock elevation data with surface elevation data using cokriging, we were able to significantly improve our map of bedrock topography without collecting additional seismic data.

  13. Dental Topography of Platyrrhines and Prosimians: Convergence and Contrasts

    E-print Network

    Boyer, Doug M.

    Dental Topography of Platyrrhines and Prosimians: Convergence and Contrasts Julia M. Winchester,1 topography with that of prosimians. We sampled 111 lower second molars of 11 platyrrhine genera and 121 of 20 prosimian genera. For each tooth we calcu- lated Dirichlet normal energy (DNE), relief index (RFI

  14. Title: Shuttle Radar Topography Mission (SRTM) Data Creator /

    E-print Network

    @yorku.ca Citation: National Aeronautics and Space Administration. "Shuttle Radar Topography Mission (SRTMTitle: Shuttle Radar Topography Mission (SRTM) Data Creator / Copyright Owner: National Aeronautics and Space Administration (NASA) Publisher: Land Information Worldwide Mapping, LLC. Edition: N/A Versions: N

  15. Quantifying landscape evolution response to changes in dynamic topography (Invited)

    NASA Astrophysics Data System (ADS)

    Moucha, R.; Ruetenik, G. A.; Braun, J.; Guillocheau, F.; Hoke, G. D.

    2013-12-01

    Earth's topography is a convolution of complex interactions of the mantle, the crust and surface processes, where the latter are controlled by the dynamics of the atmosphere and sea level change. An outstanding problem in landscape evolution and continental dynamics is the delineation of mantle convective flow induced topography (termed dynamic topography) from the geological record. Therefore, to unravel this record, we need to first understand the complex landscape evolution response to long-term dynamic forcing from the mantle in a controlled study. Recent advances in landscape evolution modeling have overcome a previous limitation in spatial and temporal scales making modeling the effects of large-scale long-term features such as dynamic topography, possible. In this study, we utilize FastScape (Braun and Willett, 2013) to quantify the effect of changes in dynamic topography of Africa on landscape evolution and sediment supply to its margins. We utilize a novel iterative approach that uses backward in time advected models of dynamic topography as the initial drivers of uplift/subsidence in the landscape evolution model. Subsequently, with the margins' sedimentary record acting as constraints we refine the changes in topography as a function of time. Our goal is to obtain a geodynamically and geologically consistent model of African topography throughout the late Cenozoic.

  16. The Global Topography of Mars and Implications for Surface

    E-print Network

    Hauck II, Steven A.

    ) and an absolute accu- racy of 13 m with respect to Mars' center of mass (COM) (12). The global topography of MarsThe Global Topography of Mars and Implications for Surface Evolution David E. Smith,1 * Maria T Zwally,1 Thomas C. Duxbury6 Elevations measured by the Mars Orbiter Laser Altimeter have yielded a high

  17. Somatic synthesis Dendritic synthesis

    E-print Network

    Schuman, Erin M.

    Spine apparatus Polysome RNP Kinesin Protein synthesis machinery mRNA transport Turnover of local protein synthesis Impact of protein × synthesis Low High Neuron size and the benefits of localRNA deep sequencing · nanostring Synaptic input patterns Control of protein translation Protein synthesis

  18. Topography of the complete corticopontine projection: from experiments to principal maps

    E-print Network

    Bjaalie, Jan G.

    Topography of the complete corticopontine projection: from experiments to principal maps Trygve B cellular components, commonly referred to as topographical organization. The topography of cortical, a principal map of the topography of corticopontine projections was developed. This map followed

  19. Topography and refractometry of nanostructures using spatial light interference microscopy (SLIM)

    E-print Network

    Gillette, Martha U.

    Topography and refractometry of nanostructures using spatial light interference microscopy (SLIM topography at a single atomic layer in graphene. Further, using a decoupling procedure that we developed high- throughput topography and refractometry of man-made and biological nanostructures. Quantitative

  20. Stereo Pair: Inverted Topography, Patagonia, Argentina

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Meseta de Somuncura is a broad plateau capped by basalt. Near its western edge is evidence of multiple volcanic events and a complex erosion history. Most notable are the long, narrow-, and winding lava flows that run across most of the right side of the image. These formed from low-viscosity lava that flowed down gullies over fairly flat terrain. Later, erosion of the landscape continued and the solidified flows were more resistant than the older surrounding rocks. Consequently, the flows became the ridges we see here. This natural process of converting gullies to ridges is called topographic inversion. See image PIA02755 (upper left corner) for a good example of topographic inversion in its earlier stages.

    Other features seen here include numerous and varied closed depressions. The regional drainage is not well integrated, and drainage ends up in salty lakes (blue if shallow, black if deep). Wind streaks indicate that winds blow toward the east (right) and blow salt grains off the lakebeds when dry. The bowtie pattern in the upper left has resulted from differing grazing practices among fenced fields.

    This cross-eyed stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with an enhanced Landsat 7satellite color image. The topography data are used to create two differing perspectives of a single image, one perspective for each eye. In doing so, each point in the image is shifted slightly, depending on its elevation. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.

    Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center,Sioux Falls, South Dakota.

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, DC.

    Size: 21.5 kilometers (13.4 miles) x 27.2 kilometers (16.9 miles) Location: 41.6 deg. South lat., 67.9 deg. West lon. Orientation: North toward upper left Image Data: Landsat bands 1,4,7 in blue, green, red Date Acquired: February 19, 2000 (SRTM), January 22, 2000 (Landsat)

  1. New Global Bathymetry and Topography Model Grids

    NASA Astrophysics Data System (ADS)

    Smith, W. H.; Sandwell, D. T.; Marks, K. M.

    2008-12-01

    A new version of the "Smith and Sandwell" global marine topography model is available in two formats. A one-arc-minute Mercator projected grid covering latitudes to +/- 80.738 degrees is available in the "img" file format. Also available is a 30-arc-second version in latitude and longitude coordinates from pole to pole, supplied as tiles covering the same areas as the SRTM30 land topography data set. The new effort follows the Smith and Sandwell recipe, using publicly available and quality controlled single- and multi-beam echo soundings where possible and filling the gaps in the oceans with estimates derived from marine gravity anomalies observed by satellite altimetry. The altimeter data have been reprocessed to reduce the noise level and improve the spatial resolution [see Sandwell and Smith, this meeting]. The echo soundings database has grown enormously with new infusions of data from the U.S. Naval Oceanographic Office (NAVO), the National Geospatial-intelligence Agency (NGA), hydrographic offices around the world volunteering through the International Hydrographic Organization (IHO), and many other agencies and academic sources worldwide. These new data contributions have filled many holes: 50% of ocean grid points are within 8 km of a sounding point, 75% are within 24 km, and 90% are within 57 km. However, in the remote ocean basins some gaps still remain: 5% of the ocean grid points are more than 85 km from the nearest sounding control, and 1% are more than 173 km away. Both versions of the grid include a companion grid of source file numbers, so that control points may be mapped and traced to sources. We have compared the new model to multi-beam data not used in the compilation and find that 50% of differences are less than 25 m, 95% of differences are less than 130 m, but a few large differences remain in areas of poor sounding control and large-amplitude gravity anomalies. Land values in the solution are taken from SRTM30v2, GTOPO30 and ICESAT data. GEBCO has agreed to adopt this model and begin updating it in 2009. Ongoing tasks include building an uncertainty model and including information from the latest IBCAO map of the Arctic Ocean.

  2. Topography and Volcanoes on Io (color)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The images used to create this enhanced color composite of Io were acquired by NASA's Galileo spacecraft during its seventh orbit (G7) of Jupiter. Low sun angles near the terminator (day-night boundary near the left side of the image) offer lighting conditions which emphasize the topography or relief on the volcanic satellite. The topography appears very flat near the active volcanic centers such as Loki Patera (the large dark horse-shoe shaped feature near the terminator) while a variety of mountains and plateaus exist elsewhere. The big reddish-orange ring in the lower right is formed by material deposited from the eruption of Pele, Io's largest volcanic plume.

    North is to the top of this picture which merges images obtained with the clear, red, green, and violet filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. The resolution is 6.1 kilometers per picture element. The images were taken on April 4th, 1997 at a range of 600,000 kilometers.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    Concurrent results from Galileo's exploration of Io appear in the October 15th, 1997 issue of Geophysical Research Letters. The papers are: Temperature and Area Constraints of the South Volund Volcano on Io from the NIMS and SSI Instruments during the Galileo G1 Orbit, by A.G. Davies, A.S. McEwen, R. Lopes-Gautier, L. Keszthelyi, R.W. Carlson and W.D. Smythe. High-temperature hot spots on Io as seen by the Galileo Solid-State Imaging (SSI) experiment, by A. McEwen, D. Simonelli, D. Senske, K. Klassen, L. Keszthelyi, T. Johnson, P. Geissler, M. Carr, and M. Belton. Io: Galileo evidence for major variations in regolith properties, by D. Simonelli, J. Veverka, and A. McEwen.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  3. Spreading of droplet with insoluble surfactant on corrugated topography

    NASA Astrophysics Data System (ADS)

    Li, Chunxi; Pei, Jianjun; Ye, Xuemin

    2014-09-01

    The flow of microscale fluid on a topography surface is a key to further development of MEMS, nanoscience and technology. In the present paper, a theoretical model of the droplet spreading with insoluble surfactant over corrugated topography is established with the lubrication theory, and the evolution equations of film thickness and surfactant concentration in base state and disturbance state are formulated. The droplet dynamics, the nonlinear stability based on nonmodal stability theory, and the effects of topography structure and Marangoni stress are numerically simulated with PDECOL scheme. Results show that the impact of topographical surface is strengthened apparently while the Marangoni stress driven by surfactant concentration is weakened in the mid-late stages of the spreading. The droplet radius on the topography advances faster and the lowest height of liquid/gas interface near the droplet edge reduces remarkably in the intermediate stage compared with those on the flat wall. The quantity of the wavelet similar to the topography increases gradually, with the characteristics of wavelet crest height with time exhibiting a single-hump feature. The spreading stability is enhanced under the disturbance wavenumber of 4, however, is to deteriorate and even to transform into instability when wavenumber increases further. In addition, the reductive Marangoni number, enhancive capillary number, modest Peclet number, the low height of the topography as well as small wavenumber of topography can make contributions to the evident stability of droplet spreading.

  4. Topography on Europa....the Shadow knows

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image of Europa was taken by the Galileo spacecraft under 'low-sun' illumination--the equivalent of taking a picture from a high altitude at sunrise or sunset. Note that in this image the topography of the terrain is emphasized. Planetary geologists use information from images acquired under a variety of lighting conditions to identify different types of structures and interpret how they formed. For example, the length of the shadow cast by a feature (e.g. a ridge or knob) is indicative of that feature's height. In this recent image, ridges and irregularly shaped knobs ranging in size from 5 kilometers across down to the limit of resolution (0.44 kilometers/pixel) can be seen. Measurements from shadow lengths indicate that features in this image range from tens of meters up to approximately one hundred meters in height.

    The Galileo spacecraft acquired this image of Europa's surface during its third orbit around Jupiter. The image covers an area approximately 40 kilometers (25 miles) by 75 kilometers (45 miles), centered near 10S, 190W.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  5. The length-scaling properties of topography

    NASA Technical Reports Server (NTRS)

    Weissel, Jeffrey K.; Pratson, Lincoln F.; Malinverno, Alberto

    1994-01-01

    The scaling properties of synthetic topographic surfaces and digital elevation models (DEMs) of topography are examined by analyzing their 'structure functions,' i.e., the qth order powers of the absolute elevation differences: delta h(sub q) (l) = E((absolute value of h(x + l) - h(x))(exp q)). We find that the relation delta h(sub 1 l) approximately equal cl(exp H) describes well the scaling behavior of natural topographic surfaces, as represented by DEMs gridded at 3 arc sec. Average values of the scaling exponent H between approximately 0.5 and 0.7 characterize DEMs from Ethiopia, Saudi Arabia, and Somalia over 3 orders of magnitude range in length scale l (approximately 0.1-150 km). Differences in appparent topographic roughness among the three areas most likely reflect differences in the amplitude factor c. Separate determination of scaling properties in the x and y coordinate directions allows us to assess whether scaling exponents are azimuthally dependent (anisotropic) or whether they are isotropic while the surface itself is anisotropic over a restricted range of length scale. We explore ways to determine whether topographic surfaces are characterized by simple or multiscaling properties.

  6. Imaging, Reconstruction, And Display Of Corneal Topography

    NASA Astrophysics Data System (ADS)

    Klyce, Stephen D.; Wilson, Steven E.

    1989-12-01

    The cornea is the major refractive element in the eye; even minor surface distortions can produce a significant reduction in visual acuity. Standard clinical methods used to evaluate corneal shape include keratometry, which assumes the cornea is ellipsoidal in shape, and photokeratoscopy, which images a series of concentric light rings on the corneal surface. These methods fail to document many of the corneal distortions that can degrade visual acuity. Algorithms have been developed to reconstruct the three dimensional shape of the cornea from keratoscope images, and to present these data in the clinically useful display of color-coded contour maps of corneal surface power. This approach has been implemented on a new generation video keratoscope system (Computed Anatomy, Inc.) with rapid automatic digitization of the image rings by a rule-based approach. The system has found clinical use in the early diagnosis of corneal shape anomalies such as keratoconus and contact lens-induced corneal warpage, in the evaluation of cataract and corneal transplant procedures, and in the assessment of corneal refractive surgical procedures. Currently, ray tracing techniques are being used to correlate corneal surface topography with potential visual acuity in an effort to more fully understand the tolerances of corneal shape consistent with good vision and to help determine the site of dysfunction in the visually impaired.

  7. Venus atmosphere and extreme surface topography

    NASA Astrophysics Data System (ADS)

    Zasova, L.; Khatuntsev, I.; Patsaeva, M.; Ignatiev, N.; Rodin, A.; Turin, A.; Markiewicz, W.; Piccioni, G.

    2015-10-01

    The temperature fields at several levels in the Venus mesosphere(60-95 km)as well as the altitude of the upper boundary of clouds retrieved from Venera-15 (FS-V15) [1], and the zonal wind fields and albedo of the upper clouds, measured by VMC Venus Express [2], and altitude of the upper boundary of clouds VIRTIS-M VEX [3] data are compared with the topographic map, obtained by Magellan [4] . The results show that the isotherms and the altitude isolines of the upper clouds boundary reproduce the extended surface features Ishtar and Atalanta Planitia. In turn, the shapes of wind isovelocities and albedo at the upper boundary of clouds (VMC) closely follow the details of relief of Terra Aphrodite as well the isolines of altitude of the cloud tops (VIRTIS). In all cases the isolines are shifted with respect to topography by about 30° in the direction of superrotation. Non-hydrostatic general circulation model of the Venus atmosphere[5] demonstrates that the major topographic features such as Maxwell Montes and Terra Aphrodite provide a prominent impact on the atmospheric dynamics at levels as high as 90-95 km.

  8. The cortical topography of local sleep.

    PubMed

    Murphy, Michael; Huber, Reto; Esser, Steve; Riedner, Brady A; Massimini, Marcello; Ferrarelli, Fabio; Ghilardi, M Felice; Tononi, Giulio

    2011-01-01

    In a recent series of experiments, we demonstrated that a visuomotor adaptation task, 12 hours of left arm immobilization, and rapid transcranial magnetic stimulation (rTMS) during waking can each induce local changes in the topography of electroencephalographic (EEG) slow wave activity (SWA) during subsequent non-rapid eye movement (NREM) sleep. However, the poor spatial resolution of EEG and the difficulty of relating scalp potentials to the activity of the underlying cortex limited the interpretation of these results. In order to better understand local cortical regulation of sleep, we used source modeling to show that plastic changes in specific cortical areas during waking produce correlated changes in SWA during sleep in those same areas. We found that implicit learning of a visuomotor adaptation task induced an increase in SWA in right premotor and sensorimotor cortices when compared to a motor control. These same areas have previously been shown to be selectively involved in the performance of this task. We also found that arm immobilization resulted in a decrease in SWA in sensorimotor cortex. Inducing cortical potentiation with repetitive transcranial magnetic stimulation (rTMS) caused an increase in SWA in the targeted area and a decrease in SWA in the contralateral cortex. Finally, we report the first evidence that these modulations in SWA may be related to the dynamics of individual slow waves. We conclude that there is a local, plasticity dependent component to sleep regulation and confirm previous inferences made from the scalp data. PMID:21906021

  9. The strength of contributions from topography mismatch and measurement filtering to simulated net ecosystem exchange in complex terrain

    NASA Astrophysics Data System (ADS)

    Brooks, B.; Desai, A. R.; Stephens, B. B.; Jacobson, A. R.

    2011-12-01

    Global scale carbon cycle inverse models provide invaluable information for the construction of empirically based carbon budgets based on in situ measurements. In landscapes of predominantly smooth topography inverse carbon cycle models are useful for diagnosing the magnitude and climate sensitivity of different regional carbon sinks. However, in landscapes of predominately complex topography inversion model results come with strong caveats for two reasons: 1) Coarse gridding of model topography can lead the model to sample observations at elevations far above the model surface, and 2) Transport wind fields over smoothed model representations of mountain regions are not always sufficiently resolved to inform the model about the source region for assimilated measurements. The uncertainty contributed by incorrect winds and topography mismatches (e.g., differences between the actual measurement elevation and model surface on the order of 1,000 m) is thought to be smaller for higher resolution regional inversion models (e.g., Gockede et al., 2010; Schuh et al. 2010), but these uncertainties are not well constrained for larger scale inversion systems (e.g., Peters et al., 2010), which are one of few ways for determining the relative priority of regional sinks. In this work we examine the effects on net ecosystem exchange (NEE) for a global scale inversion system when 1) topography mismatches are ameliorated, and 2) subset observations consistent with model resolution are used rather than observation-based subsets. Our focus is to use an example inversion model system, CarbonTracker (Peters et al., 2007; 2010), driven by CO2 mixing ratio measurements, including the RACCOON Network in the United States Mountain West (raccoon.ucar.edu), to quantify and compare the contribution to NEE from tower elevation mismatches and filtering strategies across biomes and and in terms of forecast skill (model data mismatch). We further compare our results to the differences in NEE over the same region from both inverse and forward models that participated in the North American Carbon Program Regional-Continental Model Synthesis.

  10. The Formation History of Olympus Mons from Paleo-Topography

    NASA Astrophysics Data System (ADS)

    Jozwiak, L. M.; Isherwood, R. J.; Andrews-Hanna, J. C.

    2011-03-01

    We use lava flows on the flanks of the flexural trough surrounding Olympus Mons to reconstruct the history of volcanic loading and flexure. We constrain the eruption history and rates using paleo-topography, flexural modeling, and crater counting.

  11. Superoleophobic Surfaces through Control of Sprayed-on Stochastic Topography

    E-print Network

    Campos, Raymond

    The liquid repellency and surface topography characteristics of coatings comprising a sprayed-on mixture of fluoroalkyl-functional precipitated silica and a fluoropolymer binder were examined using contact and sliding angle ...

  12. Tectonic control on the persistence of glacially sculpted topography

    NASA Astrophysics Data System (ADS)

    Prasicek, Günther; Larsen, Isaac J.; Montgomery, David R.

    2015-08-01

    One of the most fundamental insights for understanding how landscapes evolve is based on determining the extent to which topography was shaped by glaciers or by rivers. More than 104 years after the last major glaciation the topography of mountain ranges worldwide remains dominated by characteristic glacial landforms such as U-shaped valleys, but an understanding of the persistence of such landforms is lacking. Here we use digital topographic data to analyse valley shapes at sites worldwide to demonstrate that the persistence of U-shaped valleys is controlled by the erosional response to tectonic forcing. Our findings indicate that glacial topography in Earth's most rapidly uplifting mountain ranges is rapidly replaced by fluvial topography and hence valley forms do not reflect the cumulative action of multiple glacial periods, implying that the classic physiographic signature of glaciated landscapes is best expressed in, and indeed limited by, the extent of relatively low-uplift terrain.

  13. Crustal thickness and support of topography on Venus

    E-print Network

    James, Peter Benjamin

    The topography of a terrestrial planet can be supported by several mechanisms: (1) crustal thickness variations, (2) density variations in the crust and mantle, (3) dynamic support, and (4) lithospheric stresses. Each of ...

  14. 2. GENERAL VIEW SHOWING RELATION OF BRIDGE TO THE TOPOGRAPHY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. GENERAL VIEW SHOWING RELATION OF BRIDGE TO THE TOPOGRAPHY OF THE APPROACH ROAD. - Speicher Bridge, Church Road over Tulpehocken Creek between Penn & North Heidelberg Townships, Bernville, Berks County, PA

  15. 23. SPILLWAY NO. 1 LOWER END TOPOGRAPHY AND SECTIONS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. SPILLWAY NO. 1 - LOWER END TOPOGRAPHY AND SECTIONS. February 1934. Reference BS-150. - Cushman No. 1 Hydroelectric Power Plant, Spillway, North Fork of Skokomish River, 5 miles West of Hood Canal, Hoodsport, Mason County, WA

  16. Finite Difference Elastic Wave Modeling Including Surface Topography

    E-print Network

    Al Muhaidib, Abdulaziz

    2011-01-01

    Surface topography and the weathered zone (i.e., heterogeneity near the earth’s surface) have great effects on elastic wave propagation. Both surface waves and body waves are contaminated by scattering and conversion by ...

  17. Tectonic control on the persistence of glacially sculpted topography.

    PubMed

    Prasicek, Günther; Larsen, Isaac J; Montgomery, David R

    2015-01-01

    One of the most fundamental insights for understanding how landscapes evolve is based on determining the extent to which topography was shaped by glaciers or by rivers. More than 10(4) years after the last major glaciation the topography of mountain ranges worldwide remains dominated by characteristic glacial landforms such as U-shaped valleys, but an understanding of the persistence of such landforms is lacking. Here we use digital topographic data to analyse valley shapes at sites worldwide to demonstrate that the persistence of U-shaped valleys is controlled by the erosional response to tectonic forcing. Our findings indicate that glacial topography in Earth's most rapidly uplifting mountain ranges is rapidly replaced by fluvial topography and hence valley forms do not reflect the cumulative action of multiple glacial periods, implying that the classic physiographic signature of glaciated landscapes is best expressed in, and indeed limited by, the extent of relatively low-uplift terrain. PMID:26271245

  18. Tectonic control on the persistence of glacially sculpted topography

    PubMed Central

    Prasicek, Günther; Larsen, Isaac J.; Montgomery, David R.

    2015-01-01

    One of the most fundamental insights for understanding how landscapes evolve is based on determining the extent to which topography was shaped by glaciers or by rivers. More than 104 years after the last major glaciation the topography of mountain ranges worldwide remains dominated by characteristic glacial landforms such as U-shaped valleys, but an understanding of the persistence of such landforms is lacking. Here we use digital topographic data to analyse valley shapes at sites worldwide to demonstrate that the persistence of U-shaped valleys is controlled by the erosional response to tectonic forcing. Our findings indicate that glacial topography in Earth's most rapidly uplifting mountain ranges is rapidly replaced by fluvial topography and hence valley forms do not reflect the cumulative action of multiple glacial periods, implying that the classic physiographic signature of glaciated landscapes is best expressed in, and indeed limited by, the extent of relatively low-uplift terrain. PMID:26271245

  19. Linear and nonlinear stratified spindown over sloping topography

    E-print Network

    Benthuysen, Jessica A

    2010-01-01

    In a stratified rotating fluid, frictionally driven circulations couple with the buoyancy field over sloping topography. Analytical and numerical methods are used to quantify the impact of this coupling on the vertical ...

  20. Engineering microscale topographies to control the cell–substrate interface

    PubMed Central

    Nikkhah, Mehdi; Edalat, Faramarz; Manoucheri, Sam; Khademhosseini, Ali

    2013-01-01

    Cells in their in vivo microenvironment constantly encounter and respond to a multitude of signals. While the role of biochemical signals has long been appreciated, the importance of biophysical signals has only recently been investigated. Biophysical cues are presented in different forms including topography and mechanical stiffness imparted by the extracellular matrix and adjoining cells. Microfabrication technologies have allowed for the generation of biomaterials with microscale topographies to study the effect of biophysical cues on cellular function at the cell–substrate interface. Topographies of different geometries and with varying microscale dimensions have been used to better understand cell adhesion, migration, and differentiation at the cellular and sub-cellular scales. Furthermore, quantification of cell-generated forces has been illustrated with micropillar topographies to shed light on the process of mechanotransduction. In this review, we highlight recent advances made in these areas and how they have been utilized for neural, cardiac, and musculoskeletal tissue engineering application. PMID:22521491

  1. Surface topography and the impact on fatigue performance

    NASA Astrophysics Data System (ADS)

    Ardi, D. T.; Li, Y. G.; Chan, K. H. K.; Blunt, L.; Bache, M. R.

    2015-03-01

    Areal characterization was applied to plain fatigue specimens manufactured from a nickel-based superalloy, Alloy 720Li, to determine the impact of machined/finished surface topography on fatigue performance of this material. Samples were subjected to fatigue testing in the as-turned and shot peened conditions to study the interaction between residual stresses and topography in influencing the fatigue performance. The turning process was deliberately manipulated to produce three distinct finishes which were subsequently given an identical shot peening, resulting in six grades of surface topography. Surface topography was found to influence fatigue even in the presence of peened compressive residual stresses by promoting crack initiation at valley sites. Both the roughness amplitude and spatial characteristics of the surface were found to be important when correlating to fatigue performance.

  2. Infragravity waves over topography: generation, dissipation, and reflection

    E-print Network

    Thomson, James M. (James McArthur)

    2006-01-01

    Ocean surface infragravity waves (periods from 20 to 200 s) observed along the southern California coast are shown to be sensitive to the bottom topography of the shelf region, where propagation is linear, and of the ...

  3. Tunable surface topographies via particle-enhanced soft composites

    E-print Network

    Guttag, Mark A. (Mark Andrew)

    2015-01-01

    We introduce a new class of particle-enhanced soft composites (PESC) that can generate, on demand, custom and reversible surface topographies, with surface features that can be highly localized. These features can be ...

  4. EAARL coastal topography--North Shore, Lake Pontchartrain, Louisiana, 2010

    USGS Publications Warehouse

    Bonisteel-Cormier, J.M.; Nayegandhi, Amar; Fredericks, Xan; Wright, C.W.; Brock, J.C.; Nagle, D.B.; Vivekanandan, Saisudha; Barras, J.A.

    2012-01-01

    This DVD contains lidar-derived coastal topography GIS datasets of a portion of the north shore of Lake Pontchartrain, Louisiana. These datasets were acquired on February 28, March 1, and March 5, 2010.

  5. SRTM Anaglyph: Inverted Topography, Patagonia, Argentina

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Meseta de Somuncura is a broad plateau capped by basalt. Near its western edge is evidence of multiple volcanic events and a complex erosion history. Most notable are the long, narrow, and winding lava flows that run across most of the right side of the image. These formed from low-viscosity lava that flowed down gullies over fairly flat terrain. Later, erosion of the landscape continued, and the solidified flows were more resistant than the older surrounding rocks. Consequently, the flows became the ridges we see here. This natural process of converting gullies to ridges is called topographic inversion. See image PIA02755 (upper left corner) for a good example of topographic inversion in its earlier stages.

    Other features seen here include numerous and varied closed depressions. The regional drainage is not well integrated, but instead the drainage ends up in salty lakes (dark water, some with bright shores). Wind streaks indicate that winds blow toward the east (right) and blow salt grains off the lake beds when dry. The bowtie pattern in the upper left has resulted from differing grazing practices among fenced fields.

    This anaglyph was generated by first draping a Landsat Thematic Mapper image over a topographic map from the Shuttle Radar Topography Mission, then producing the two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and the right eye with a blue filter.

    Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center,Sioux Falls, South Dakota.

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, DC.

    Size: 21.5 kilometers (13.4 miles) x 27.2 kilometers (16.9 miles) Location: 41.6 deg. South lat., 67.9 deg. West lon. Orientation: North toward upper left Image Data: Landsat band 7 (short infrared) Date Acquired: February 19, 2000 (SRTM), January 22, 2000 (Landsat)

  6. Lower mantle heterogeneity, dynamic topography and the geoid

    NASA Technical Reports Server (NTRS)

    Hager, B. H.; Clayton, R. W.; Richards, M. A.; Comer, R. P.; Dziewonski, A. M.

    1984-01-01

    Density contrasts in the lower mantle, recently imaged using seismic tomography, drive convective flow which results in kilometers of dynamically maintained topography at the core-mantle boundary and at the Earth's surface. The total gravity field due to interior density contrasts and boundary topography predicts the largest wavelength components of the geoid remarkably well. Neglecting dynamic surface deformation leads to geoid anomalies of opposite sign than are observed.

  7. The Role of African topography in the South Asian Monsoon

    NASA Astrophysics Data System (ADS)

    Wei, H. H.; Bordoni, S.

    2014-12-01

    The Somali cross-equatorial jet is estimated to contribute up to half of the mass flux crossing the equator during the Asian monsoon season. Previous studies have argued that the Somali jet is strengthened by the East African Highlands, which act as a wall and accelerate the flow (e.g., Krishnamurti et al. 1976, Sashegyi and Geisler 1987). Besides, observational studies have shown a positive correlation between the strength of the Somali jet and the South Asian Monsoon (SAM) precipitation (e.g., Findlater 1969, Halpern and Woiceshyn 2001). These imply that the existence of the topography would relate to a stronger SAM. However, in a more recent study, Chakraborty et al. (2002) found that if the African topography is removed in a comprehensive general circulation model (GCM), the SAM strengthens. In this study, we use the GFDL AM2.1 GCM to conduct experiments with and without topography in Africa, to further examine its influence on the cross-equatorial Somali jet and the SAM. We find that when the African topography is removed, the SAM precipitation increases, consistent with the results in Chakraborty et al. (2002). Interestingly, our results also show that the cross-equatorial Somali jet does weaken in the absence of the African topography, in agreement with previous studies. The moisture budget shows that the increase in precipitation in the no-African topography experiment is primarily due to stronger wind convergence. The dynamics of the cross-equatorial Somali jet is investigated within the framework of the Potential Vorticity (PV) budget, showing the contribution of the changes in friction and diabatic heating to the circulation as the topography is removed. A backward trajectory analysis is also conducted to further examine the influence of topography on both the material tendencies of the PV budget and trajectories of parcels reaching the Indian subcontinent.

  8. Global dynamic topography: geoscience communities requirements

    NASA Astrophysics Data System (ADS)

    Dewez, T.; Costeraste, J.

    2012-04-01

    The advent of free-of-charge global topographic data sets SRTM and Aster GDEM have enabled testing a host of geoscience hypotheses. This is because they first revealed the relief of previously unavailable earth landscapes, enabled quantitative geomorphometric analyses across entire landscapes and improved the resolution of measurements. Availability of such data is now considered standard, and though resolved at 30-m to 90-m pixel, which is amazing seeing where we come from, they are now regarded as mostly obsolete given the sub-meter imagery coming through web services like Google Earth. Geoscientists now appear to desire two additional features: field-scale-compatible elevation datasets (i.e. meter-scale digital models and sub-meter elevation precision) and dispose of regularly updated topography to retrieve earth surface changes, while retaining the key for success: data availability at no charge. A new satellite instrument is currently under phase 0 study at CNES, the French space agency, to fulfil these aims. The scientific community backing this demand is that of natural hazards, glaciology and to a lesser extent the biomass community. The system under study combines a native stereo imager and a lidar profiler. This combination provides spatially resolved elevation swaths together with absolute along-track elevation control point profiles. Data generated through this system, designed for revisit time better than a year, is intended to produce not only single acquisition digital surface models, colour orthoimages and small footprint full-wave-form lidar profiles to update existing topographic coverages, but also time series of them. This enables 3D change detection with centimetre-scale planimetric precision and metric vertical precision, in complement of classical spectral change appoaches. The purpose of this contribution, on behalf of the science team, is to present the mission concepts and philosophy and the scientific needs for such instrument including foreseen societal benefits.

  9. Science in Motion: Isolated Araneiform Topography

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1

    Have you ever found that to describe something you had to go to the dictionary and search for just the right word?

    The south polar terrain is so full of unearthly features that we had to visit Mr. Webster to find a suitable term. 'Araneiform' means 'spider-like'. These are channels that are carved in the surface by carbon dioxide gas. We do not have this process on Earth.

    The channels are somewhat radially organized (figure 1) and widen and deepen as they converge. In the past we've just refered to them as 'spiders.' 'Isolated araneiform topography' means that our features look like spiders that are not in contact with each other.

    Observation Geometry Image PSP_003087_0930 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 24-Mar-2007. The complete image is centered at -87.1 degrees latitude, 126.3 degrees East longitude. The range to the target site was 244.4 km (152.8 miles). At this distance the image scale is 24.5 cm/pixel (with 1 x 1 binning) so objects 73 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel . The image was taken at a local Mars time of 08:22 PM and the scene is illuminated from the west with a solar incidence angle of 81 degrees, thus the sun was about 9 degrees above the horizon. At a solar longitude of 206.4 degrees, the season on Mars is Northern Autumn.

  10. Evolution of Topography in Glaciated Mountain Ranges

    NASA Technical Reports Server (NTRS)

    Brocklehurst, Simon H.

    2002-01-01

    This thesis examines the response of alpine landscapes to the onset of glaciation. The basic approach is to compare fluvial and glacial laudscapes, since it is the change from the former to the latter that accompanies climatic cooling. This allows a detailed evaluation of hypotheses relating climate change to tectonic processes in glaciated mountain belts. Fieldwork was carried out in the eastern Sierra Nevada, California, and the Sangre de Cristo Range, Colorado, alongside digital elevation model analyses in the western US, the Southern Alps of New Zealand, and the Himalaya of northwestern Pakistan. hypothesis is overstated in its appeal to glacial erosion as a major source of relief production and subsequent peak uplift. Glaciers in the eastern Sierra Nevada and the western Sangre de Cristos have redistributed relief, but have produced only modest relief by enlarging drainage basins at the expense of low-relief topography. Glaciers have lowered valley floors and ridgelines by similar amounts, limiting the amount of "missing mass' that can be generated, and causing a decrease in drainage basin relief. The principal response of glaciated landscapes to rapid rock uplift is the development of towering cirque headwalls. This represents considerable relief production, but is not caused by glacial erosion alone. Large valley glaciers can maintain their low gradient regardless of uplift rate, which supports the "glacial buzzsaw" hypothesis. However, the inability of glaciers to erode steep hillslopes as rapidly can cause mean elevations to rise. Cosmogenic isotope dating is used to show that (i) where plucking is active, the last major glaciation removed sufficient material to reset the cosmogenic clock; and (ii) former glacial valley floors now stranded near the crest of the Sierra Nevada are at varying stages of abandonment, suggesting a cycle of drainage reorganiszation and relief inversion due to glacial erosion similar to that observed in river networks. Glaciated landscapes are quite distinct from their fluvial counterparts in both landforms and processes. Given the scarcity of purely fluvial, active mountain ranges, it is essential that glacial erosion be considered amongst the processes sculpting active orogenic belts.

  11. Shuttle Topography Data Inform Solar Power Analysis

    NASA Technical Reports Server (NTRS)

    2013-01-01

    The next time you flip on a light switch, there s a chance that you could be benefitting from data originally acquired during the Space Shuttle Program. An effort spearheaded by Jet Propulsion Laboratory (JPL) and the National Geospatial-Intelligence Agency (NGA) in 2000 put together the first near-global elevation map of the Earth ever assembled, which has found use in everything from 3D terrain maps to models that inform solar power production. For the project, called the Shuttle Radar Topography Mission (SRTM), engineers at JPL designed a 60-meter mast that was fitted onto Shuttle Endeavour. Once deployed in space, an antenna attached to the end of the mast worked in combination with another antenna on the shuttle to simultaneously collect data from two perspectives. Just as having two eyes makes depth perception possible, the SRTM data sets could be combined to form an accurate picture of the Earth s surface elevations, the first hight-detail, near-global elevation map ever assembled. What made SRTM unique was not just its surface mapping capabilities but the completeness of the data it acquired. Over the course of 11 days, the shuttle orbited the Earth nearly 180 times, covering everything between the 60deg north and 54deg south latitudes, or roughly 80 percent of the world s total landmass. Of that targeted land area, 95 percent was mapped at least twice, and 24 percent was mapped at least four times. Following several years of processing, NASA released the data to the public in partnership with NGA. Robert Crippen, a member of the SRTM science team, says that the data have proven useful in a variety of fields. "Satellites have produced vast amounts of remote sensing data, which over the years have been mostly two-dimensional. But the Earth s surface is three-dimensional. Detailed topographic data give us the means to visualize and analyze remote sensing data in their natural three-dimensional structure, facilitating a greater understanding of the features and processes taking place on Earth."

  12. Overland Tsunami Flow through Complex Topography

    NASA Astrophysics Data System (ADS)

    Lynett, P. J.; Cox, D. T.; Park, H.; Wiebe, D. M.

    2012-12-01

    As seen in numerous Japanese eyewitness videos that captured the tsunami inundation on March 11th 2011, flow interaction with the built environment is extremely complex. In addition to the entrainment of sediment and large discrete objects such as cars and ships, tsunami energy amplification due to topographic focusing was widely observed. In coastal towns and cities, this topographic focusing was due to large structures which channelled the flow to either side, often through roadways or other low-obstruction pathways. Structures in the "line-of-fire" of this channelized flow were often found to have been inflicted with relatively greater levels of damage, while the opposite was true for structures in the flow-shadow of large buildings. In this presentation, we attempt to quantify the hydrodynamic variability of flow through complex topography, such as a city layout. Understanding this variability is of particular relevance to on-going engineering efforts to develop standards for tsunami design of coastal structures. A novel set of large-scale experimental data will be introduced and used to validate a depth-integrated model. The experiment was performed in the Tsunami Wave Basin at Oregon State University. Transient long wave flooding in a 1/50 scale model of the town of Seaside, Oregon was tested. Data from the experiment, including water elevations and co-located flow speeds, are used to confirm the simulated dynamics in the numerical model. The model is shown to be capable of accurately reproducing the instantaneous wave elevation, velocity, and momentum flux of a long wave flooding a town. It is found that the numerical prediction is sensitive to the value of the bottom roughness coefficient. The model is then extended to look at the hydrodynamics in more detail and for other cases. Predicted momentum flux values from with structures resolved, with-out structures resolved, and with spatially variable bottom roughness will be discussed. It is found that localized maximum momentum flux values can be two orders of magnitude greater than the alongshore-transect mean. A method to calculate statistical variability of hydrodynamic flow properties, such as might be used in a risk-based analysis, will be discussed.

  13. Linear baroclinic instability in the presence of large scale topography

    NASA Technical Reports Server (NTRS)

    Reynolds, Nathaniel Dunton

    1987-01-01

    The effect of a planetary-scale, wavenumber 2 topography on baroclinically active disturbances is investigated for a channel domain in a two-layer, quasi-geostrophic context. When the lower-layer zonal velocity is nonzero, the topography influences the disturbances by forcing a stationary wave, and the topography and the forced wave influence the growth rates and the spatial structures of the time-dependent solutions. The case of zero zonal velocity in the lower layer was also investigated, for which no forced wave exists. Asymptotic forms of the equations, valid when the topographic effect (governed by the ratio of the nondimensional topographic height to the rotational Froude number) is small, are used to obtain both the stationary and time-dependent solutions. The latter are also obtained using a numerical approach, in which is determined the eigenvalues and eigenfunctions of a matrix representing the dynamical equations. Agreement is good between the two approaches. Recent laboratory experiments with a baroclinic annulus in which there is a false bottom with wavenumber 2 topography, are used to select governing parameters. The simultaneous presence of a stationary forced wave of wavenumber 2 and a time-dependent baroclinic wave of wavenumber 4, which has wavenumber 2 and 6 sidebands due to the topography, yields a flow field that exhibits some principal features of the laboratory experiments. The position of the forced wave and the location of an excursion in latitude of the storm track show qualitative resemblance to those features observed in the atmosphere.

  14. Corneal topography from spectral optical coherence tomography (sOCT)

    PubMed Central

    Ortiz, Sergio; Siedlecki, Damian; Pérez-Merino, Pablo; Chia, Noelia; de Castro, Alberto; Szkulmowski, Maciej; Wojtkowski, Maciej; Marcos, Susana

    2011-01-01

    We present a method to obtain accurate corneal topography from a spectral optical coherence tomography (sOCT) system. The method includes calibration of the device, compensation of the fan (or field) distortion introduced by the scanning architecture, and image processing analysis for volumetric data extraction, segmentation and fitting. We present examples of three-dimensional (3-D) surface topography measurements on spherical and aspheric lenses, as well as on 10 human corneas in vivo. Results of sOCT surface topography (with and without fan-distortion correction) were compared with non-contact profilometry (taken as reference) on a spherical lens, and with non-contact profilometry and state-of-the art commercial corneal topography instruments on aspheric lenses and on subjects. Corneal elevation maps from all instruments were fitted by quadric surfaces (as well as by tenth-order Zernike polynomials) using custom routines. We found that the discrepancy in the estimated radius of curvature from nominal values in artificial corneas decreased from 4.6% (without fan distortion correction) to 1.6% (after fan distortion correction), and the difference in the asphericity decreased from 130% to 5%. In human corneas, the estimated corneal radius of curvature was not statistically significantly different across instruments. However, a Bland-Altman analysis showed consistent differences in the estimated asphericity and corneal shape between sOCT topographies without fan distortion correction and the rest of the measurements. PMID:22162814

  15. Controls on (anomalous) topography in rifted margin settings

    NASA Astrophysics Data System (ADS)

    Huismans, Ritske S.

    2015-04-01

    Contrasting end members of volcanic and non-volcanic passive margin formation show a large variability in basin shape and structure, subsidence history, and associated topographic evolution of the onshore rifted margins. The large range of structural style and associated topography of these systems imply a strong variability in the underlying thermo-mechanical conditions at the time of rifting. Rift - passive margin styles ranging from narrow to ultra wide are explained using forward numerical models with varying rheological structure, with strong crust lithosphere leading to narrow rift formation associated with highly elevated rift shoulders and conversely weak crust lithosphere resulting in highly stretched wide rifted conjugate margins and little flank morphology. In some cases rifted margins appear to indicate the formation of anomalous post rift topography. A number of mechanisms including small-scale convective removal of the lower lithosphere, lithosphere counter-flow, and dynamic topography, have been invoked to explain the anomalous topography. Forward numerical models are used to predict the magnitude and characteristic topography associated with each of these mechanisms and to evaluate their potential for explaining these apparent anomalous characteristics of rifts and rifted margins.

  16. Crystal quality analysis and improvement using x-ray topography.

    SciTech Connect

    Maj, J.; Goetze, K.; Macrander, A.; Zhong, Y.; Huang, X.; Maj, L.; Univ. of Chicago

    2008-01-01

    The Topography X-ray Laboratory of the Advanced Photon Source (APS) at Argonne National Laboratory operates as a collaborative effort with APS users to produce high performance crystals for APS X-ray beamline experiments. For many years the topography laboratory has worked closely with an on-site optics shop to help ensure the production of crystals with the highest quality, most stress-free surface finish possible. It has been instrumental in evaluating and refining methods used to produce high quality crystals. Topographical analysis has shown to be an effective method to quantify and determine the distribution of stresses, to help identify methods that would mitigate the stresses and improve the Rocking curve, and to create CCD images of the crystal. This paper describes the topography process and offers methods for reducing crystal stresses in order to substantially improve the crystal optics.

  17. Laser-based nanoengineering of surface topographies for biomedical applications

    NASA Astrophysics Data System (ADS)

    Schlie, Sabrina; Fadeeva, Elena; Koroleva, Anastasia; Ovsianikov, Aleksandr; Koch, Jürgen; Ngezahayo, Anaclet; Chichkov, Boris. N.

    2011-04-01

    In this study femtosecond laser systems were used for nanoengineering of special surface topographies in silicon and titanium. Besides the control of feature sizes, we demonstrated that laser structuring caused changes in material wettability due to a reduced surface contact area. These laser-engineered topographies were tested for their capability to control cellular behavior of human fibroblasts, SH-SY5Y neuroblastoma cells, and MG-63 osteoblasts. We found that fibroblasts reduced cell growth on the structures, while the other cell types proliferated at the same rate. These findings make laser-surface structuring very attractive for biomedical applications. Finally, to explain the results the correlation between topography and the biophysics of cellular adhesion, which is the key step of selective cell control, is discussed.

  18. Implications of MOLA Global Roughness, Statistics, and Topography

    NASA Technical Reports Server (NTRS)

    Aharonson, O.; Zuber, M. T.; Neumann, G. A.

    1999-01-01

    New insights are emerging as the ongoing high-quality measurements of the Martian surface topography by Mars Orbiter Laser Altimeter (MOLA) on board the Mars Global Surveyor (MGS) spacecraft increase in coverage, resolution, and diversity. For the first time, a global characterization of the statistical properties of topography is possible. The data were collected during the aerobreaking hiatus, science phasing, and mapping orbits of MGS, and have a resolution of 300-400 m along track, a range resolution of 37.5 cm, a range precision of 1-10 m for surface slopes up to 30 deg., and an absolute accuracy of topography of 13 m. The spacecraft's orbit inclination dictates that nadir observations have latitude coverage of about 87.1S to 87.1N; the addition of observations obtained during a period of off-nadir pointing over the north pole extended coverage to 90N. Additional information is contained in the original extended abstract.

  19. A scanning radar altimeter for mapping continental topography

    NASA Technical Reports Server (NTRS)

    Dixon, T. H.

    1986-01-01

    Topographic information constitutes a fundamental data set for the Earth sciences. In the geological and geophysical sciences, topography combined with gravitational information provides an important constraint on the structure and rheologic properties of the crust and lithosphere. Detailed topography data can also be used to map offsets associated with faulting and to reveal the effects of tectonic deformation. In the polar regions, elevation data form a crucial but as yet largely unavailable resource for studying ice sheet mass balance and ice flow dynamics. The vast Antarctic ice sheet is the largest fresh water reservoir on Earth and is an important influence on ocean circulation and global climate. However, our knowledge of its stability is so limited that we cannot even specify whether the Antarctic ice sheet is growing or shrinking. It is clear that there is need for high quality global topography data. A summary of potential applications with their resolution requirements is shown.

  20. Sintered silver joints via controlled topography of electronic packaging subcomponents

    DOEpatents

    Wereszczak, Andrew A.

    2014-09-02

    Disclosed are sintered silver bonded electronic package subcomponents and methods for making the same. Embodiments of the sintered silver bonded EPSs include topography modification of one or more metal surfaces of semiconductor devices bonded together by the sintered silver joint. The sintered silver bonded EPSs include a first semiconductor device having a first metal surface, the first metal surface having a modified topography that has been chemically etched, grit blasted, uniaxial ground and/or grid sliced connected to a second semiconductor device which may also include a first metal surface with a modified topography, a silver plating layer on the first metal surface of the first semiconductor device and a silver plating layer on the first metal surface of the second semiconductor device and a sintered silver joint between the silver plating layers of the first and second semiconductor devices which bonds the first semiconductor device to the second semiconductor device.

  1. Ulva linza zoospore sensitivity to systematic variation of surface topography

    NASA Astrophysics Data System (ADS)

    Sheats, Julian Taylor

    The use of surface topographical microstructure is abundant in nature. The lotus plant uses a fractal-like topography to create a highly non-wetting surface that self-cleans as water drops take dirt particles with them as they roll off. Analysis of how topography affects surface interactions offers a unique opportunity to attack a problem that affects our economy and societal health significantly. The attachment of biological material to manmade surfaces can be looked at as fouling or directed adhesion. Marine fouling on ship hulls costs the United States $600 million each year due to increased fuel usage caused by drag. Hospital-acquired methicillin-resistant Staphylococcus aureus infections cause thousands of deaths annually as a result of colonization of hospital surfaces. The lack of biocompatible synthetic surfaces for implants such as vascular grafts lead to restenosis as cells are unable to develop a natural interaction with the graft surface. In each circumstance there is much to learn about the complicated attachment process. This work expands the investigation of the role of topography in the attachment of the green fouling algae Ulva linza to poly(dimethylsiloxane) surfaces. Spore attachment density was correlated to the Wenzel roughness ratio on low surface energy, high-modulus poly(dimethylsiloxane)-grafted-silicon topographies. The role of topography on a scale less than the size of a spore was investigated on nano-roughened poly(dimethylsiloxane) elastomer surfaces. For a specific group of patterns, the spatial distribution of spores attached to topographies was quantitatively analyzed and shown to correlate with feature dimensions.

  2. Effect of topography on sulfate redistribution in Cumulonimbus cloud development.

    PubMed

    Vujovi?, Dragana; Vu?kovi?, Vladan; Curi?, Mla?en

    2014-03-01

    An aqueous chemical module is created and included into a complex three-dimensional atmospheric cloud-resolving mesoscale model. In the chemical module, oxidation of S(IV) by ozone and hydrogen peroxide in cloud-water and rainwater, as important process of the sulfate production is included. To examine the impact of topography on the sulfate redistribution in a clean and a polluted environment, the complex topography of Serbia is included in the model. Numerical simulations of an isolated summer Cumulonimbus cloud shows that thunderstorms generate very strong vertical sulfate redistribution from the planetary boundary layer to the upper troposphere. This redistribution is sensitive to cloud dynamics, while cloud microphysics and precipitation determine wet removal of the chemical species. In simulations with realistic topography, the chemical species are transported over larger distances close to the surface, while in the upper atmosphere, there is no difference compared to the simulations without topography. The sensitivity tests of cloud chemistry to the physical processes are made. Omission of nucleation and impact scavenging of aerosols in the model simulations shows that 75.8 and 62.5 % of total sulfur mass deposited in the base experiment for the clean and the polluted environment, respectively, is the result of other processes. Exclusion of oxidation accounted for 19.2 and 37.7 % of total sulfur deposited for clean and polluted environment. Ignoring the ice phase almost not change mass of deposited sulfur: there is an increase of 2.9 and 1.5 % for clean and polluted atmosphere, respectively. Real topography conditions affect the sulfate redistribution in the sense of greater possibilities of transport. Numerical simulations without real topography give an artificial increase of deposited sulfur mass of about 25-30 %. PMID:24243093

  3. Dynamic topography in subduction zones: insights from laboratory models

    NASA Astrophysics Data System (ADS)

    Bajolet, Flora; Faccenna, Claudio; Funiciello, Francesca

    2014-05-01

    The topography in subduction zones can exhibit very complex patterns due to the variety of forces operating this setting. If we can deduce the theoretical isostatic value from density structure of the lithosphere, the effect of flexural bending and the dynamic component of topography are difficult to quantify. In this work, we attempt to measure and analyze the topography of the overriding plate during subduction compared to a pure shortening setting. We use analog models where the lithospheres are modeled by thin-sheet layers of silicone putty lying on low-viscosity syrup (asthenosphere). The model is shorten by a piston pushing an oceanic plate while a continental plate including a weak zone to localize the deformation is fixed. In one type of experiments, the oceanic plate bends and subducts underneath the continental one; in a second type the two plates are in contact without any trench, and thus simply shorten. The topography evolution is monitored with a laser-scanner. In the shortening model, the elevation increases progressively, especially in the weak zone, and is consistent with expected isostatic values. In the subduction model, the topography is characterized, from the piston to the back-wall, by a low elevation of the dense oceanic plate, a flexural bulge, the trench forming a deep depression, the highly elevated weak zone, and the continental upper plate of intermediate elevation. The topography of the upper plate is consistent with isostatic values for very early stages, but exhibits lower elevations than expected for later stages. For a same amount of shortening of the continental plate, the thickening is the same and the plate should have the same elevation in both types of models. However, comparing the topography at 20, 29 and 39% of shortening, we found that the weak zone is 0.4 to 0.6 mm lower when there is an active subduction. Theses values correspond to 2.6 to 4 km in nature. Although theses values are high, there are of the same order as dynamic topography and could represent the dynamic effect of the slab sinking into the asthenosphere and lowering the elevation of the upper plate.

  4. Airborne Lidar Simulator for the Lidar Surface Topography (LIST) Mission

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Krainak, Michael A.; Abshire, James B.; Cavanaugh, John; Valett, Susan; Ramos-Izquierdo, Luis

    2010-01-01

    In 2007, the National Research Council (NRC) completed its first decadal survey for Earth science at the request of NASA, NOAA, and USGS. The Lidar Surface Topography (LIST) mission is one of fifteen missions recommended by NRC, whose primary objectives are to map global topography and vegetation structure at 5 m spatial resolution, and to acquire global surface height mapping within a few years. NASA Goddard conducted an initial mission concept study for the LIST mission in 2007, and developed the initial measurement requirements for the mission.

  5. Sound propagation over uneven ground and irregular topography

    NASA Technical Reports Server (NTRS)

    Berthelot, Yves H.; Pierce, Allan D.; Kearns, James A.; Zhou, Ji-Xun

    1988-01-01

    Theoretical, computational, and experimental techniques were developed for predicting the effects of irregular topography on long range sound propagation in the atmosphere. Irregular topography is understood to imply a ground surface that: (1) is not idealizable as being perfectly flat, or (2) that is not idealizable as having a constant specific acoustic impedance. The focus is on circumstances where the propagation is similar to what might be expected for noise from low altitude air vehicles flying over suburban or rural terrain, such that rays from the source arrive at angles close to grazing incidence.

  6. Influence of surface topography on the multilayer film formation

    SciTech Connect

    Grishchenko, Yu. V.; Zanaveskin, M. L.; Tolstikhina, A. L.

    2010-01-15

    The relationship between the topography of substrates and multilayer films deposited on these substrates (which are used in ring laser gyroscopes) has been investigated. The surfaces were studied by atomic-force microscopy. The statistical properties of the surface topography are analyzed within the approach based on a comparative analysis of the power spectral density functions of roughness calculated for the substrate and film. The degree of correlation between the substrate nanotopography and multilayer film is determined, and the influence of the substrate roughness on the optical characteristics of the deposited mirrors is established.

  7. Topography influence on the Lake equations in bounded domains

    E-print Network

    Christophe Lacave; Toan T. Nguyen; Benoit Pausader

    2013-06-10

    We investigate the influence of the topography on the lake equations which describe the two-dimensional horizontal velocity of a three-dimensional incompressible flow. We show that the lake equations are structurally stable under Hausdorff approximations of the fluid domain and $L^p$ perturbations of the depth. As a byproduct, we obtain the existence of a weak solution to the lake equations in the case of singular domains and rough bottoms. Our result thus extends earlier works by Bresch and M\\'etivier treating the lake equations with a fixed topography and by G\\'erard-Varet and Lacave treating the Euler equations in singular domains.

  8. Sound propagation over uneven ground and irregular topography

    NASA Technical Reports Server (NTRS)

    Pierce, A. D.; Main, G. L.; Kearns, J. A.; Benator, D. R.; Parish, J. R., Jr.

    1986-01-01

    The development of theoretical, computational, and experimental techniques for predicting the effects of irregular topography on long range sound propagation in the atmosphere is discussed. Irregular topography here is understood to imply a ground surface that (1) is not idealizable as being perfectly flat or (2) that is not idealizable as having a constant specific acoustic impedance. The study focuses on circumstances where the propagation is similar to what might be expected for noise from low-altitude air vehicles flying over suburban or rural terrain, such that rays from the source arrive at angles close to grazing incidence.

  9. Geoid, topography, and convection-driven crustal deformation on Venus

    NASA Technical Reports Server (NTRS)

    Simons, Mark; Hager, Bradford H.; Solomon, Sean C.

    1992-01-01

    High-resolution Magellan images and altimetry of Venus reveal a wide range of styles and scales of surface deformation that cannot readily be explained within the classical terrestrial plate tectonic paradigm. The high correlation of long-wavelength topography and gravity and the large apparent depths of compensation suggest that Venus lacks an upper-mantle low-viscosity zone. A key difference between Earth and Venus may be the degree of coupling between the convecting mantle and the overlying lithosphere. Mantle flow should then have recognizable signatures in the relationships between surface topography, crustal deformation, and the observed gravity field.

  10. Research of the Method of Local Topography Rapid Reconstructed

    NASA Astrophysics Data System (ADS)

    Zhao, Minrong; Deng, Shengli; Shi, Ze

    For fast and convenient access to the environment based on the geomorphic characteristics of camouflage regional model for the complexity of topography, this article analyzes a variety of terrain modeling method’s advantages and limitations, discussed a variety of modeling methods in the set up of the study of basic on the hybrid modeling method and the integrated use of research results to generate the details of the existing landform characteristics can be controlled on all-terrain results. Generate local terrain adaptive modeling method, as a regional model disguised form with the local terrain topography of the region to adapt to a good camouflage effect.

  11. Mercury's Thermal Evolution, Dynamical Topography and Geoid

    NASA Astrophysics Data System (ADS)

    Ziethe, Ruth; Benkhoff, Johannes

    Among the terrestrial planets Mercury is not only the smallest, but also the densest (after correction for self-compression). To explain Mercury's high density it is considered likely that the planet's mantle was removed during a giant impact event, when proto-Mercury was already differentiated into an iron core and a silicate mantle. Beside the damage to the planet's mantle the vaporization would cause a significant loss of volatile elements, leaving the remaining planet molten and dominated by extremely refractory material.Since the arrival of a spacecraft at the enigmatic planet is not to be expected before 2011 (Messenger) or 2019 (BepiColombo) we might already prepare ourselves for the upcoming results and perform tests that allow some anticipation of the measured data. The hermean mantle is modelled as an internally and bottom heated, isochemical fluid in a spherical shell. The principle of this convection model is widely accepted and is used for various models of thermal evolution of terrestrial planets, e.g., the Earth, Mars or the Moon. We are solving the hydrodynamical equations, derived from the conservation of mass, momentum and energy. A program originally written by S. Zhang is used to solve the temperature field which employs a combination of a spectral and a finite difference method. Beside the large core as a heat source 'from below' the decay of radioactive isotopes provides internal heating of the hermean mantle. The viscosity of the mantel material depends exponentially on the inverse temperature. The model results show the typical behaviour of a one-plate-planet, meaning the surface is not broken into several tectonic plates but the outside is a single rigid shell. The thermal evolution is generally charaterized by the growth of a massive lithosphere on top of the convecting mantle. The lower mantle and core cool comparatively little and stay at temperatures between 1900K and 2000K until about 2.0Ga after the simulation was started. The stagnant lid comprises roughly half the mantle after only 0.5Ga. Since the rigid lithosphere does not take part in the convection anymore, the heat coming from the interior (due to the cooling of the large core) can only be transported through the lithosphere by thermal conduction. This is a significantly less effective mechanism of heat transport than convection and hence the lithosphere forms an insulating layer. As a result, the interior is kept relatively warm.Because the mantle is relatively shallow compared to the planet's radius, and additionally the thick stagnant lid is formed relatively rapid, the convection is confined to a layer of only about 200km to 300km. Convection structures are therefore relatively small structured. The flow patterns in the early evolution show that mantle convection is characterized by numerous upwelling plumes, which are fed by the heat flow from the cooling core. These upwellings are relatively stable regarding their spatial position. As the core cools down the temperature anomalies become colder and less pronounced but not less numerous. In our calculations, a region of partial melt in the mantle forms immediately after the start of the model at a depths of roughly 220km. While in the entire lower mantle the temperature exceeds the solidus, the highest melt degrees can be found in the upwelling plumes. The partial molten region persists a significant time (up to 2.5Ga). How long the partial molten zone actually survives depends strongly on the initial conditions of the model. For instance, an outer layer with a reduced thermal conductivity would keep the lower mantle significantly warmer and a molten layer survives longer. The hot upwellings cause a surface deformation (dynamical topography) which itself causes a gravity anomaly. Due to the weak constraints of important parameters (e.g. sulfur content of the core, mantle rheology, amount and distribution of radiogenic heat sources, planetary contraction, thermal conductivity, etc) numerous models are required to understand the importance and influence of the mentioned variables.

  12. Payload topography camera of Chang'e-3

    NASA Astrophysics Data System (ADS)

    Yu, Guo-Bin; Liu, En-Hai; Zhao, Ru-Jin; Zhong, Jie; Zhou, Xiang-Dong; Zhou, Wu-Lin; Wang, Jin; Chen, Yuan-Pei; Hao, Yong-Jie

    2015-11-01

    Chang'e-3 was China's first soft-landing lunar probe that achieved a successful roving exploration on the Moon. A topography camera functioning as the lander's “eye” was one of the main scientific payloads installed on the lander. It was composed of a camera probe, an electronic component that performed image compression, and a cable assembly. Its exploration mission was to obtain optical images of the lunar topography in the landing zone for investigation and research. It also observed rover movement on the lunar surface and finished taking pictures of the lander and rover. After starting up successfully, the topography camera obtained static images and video of rover movement from different directions, 360° panoramic pictures of the lunar surface around the lander from multiple angles, and numerous pictures of the Earth. All images of the rover, lunar surface, and the Earth were clear, and those of the Chinese national flag were recorded in true color. This paper describes the exploration mission, system design, working principle, quality assessment of image compression, and color correction of the topography camera. Finally, test results from the lunar surface are provided to serve as a reference for scientific data processing and application.

  13. Recent advances in engineering topography mediated antibacterial surfaces

    NASA Astrophysics Data System (ADS)

    Hasan, Jafar; Chatterjee, Kaushik

    2015-09-01

    The tendency of bacterial cells to adhere and colonize a material surface leading to biofilm formation is a fundamental challenge underlying many different applications including microbial infections associated with biomedical devices and products. Although, bacterial attachment to surfaces has been extensively studied in the past, the effect of surface topography on bacteria-material interactions has received little attention until more recently. We review the recent progress in surface topography based approaches for engineering antibacterial surfaces. Biomimicry of antibacterial surfaces in nature is a popular strategy. Whereas earlier endeavors in the field aimed at minimizing cell attachment, more recent efforts have focused on developing bactericidal surfaces. However, not all such topography mediated bactericidal surfaces are necessarily cytocompatible thus underscoring the need for continued efforts for research in this area for developing antibacterial and yet cytocompatible surfaces for use in implantable biomedical applications. This mini-review provides a brief overview of the current strategies and challenges in the emerging field of topography mediated antibacterial surfaces.

  14. Recent advances in engineering topography mediated antibacterial surfaces.

    PubMed

    Hasan, Jafar; Chatterjee, Kaushik

    2015-10-14

    The tendency of bacterial cells to adhere and colonize a material surface leading to biofilm formation is a fundamental challenge underlying many different applications including microbial infections associated with biomedical devices and products. Although, bacterial attachment to surfaces has been extensively studied in the past, the effect of surface topography on bacteria-material interactions has received little attention until more recently. We review the recent progress in surface topography based approaches for engineering antibacterial surfaces. Biomimicry of antibacterial surfaces in nature is a popular strategy. Whereas earlier endeavors in the field aimed at minimizing cell attachment, more recent efforts have focused on developing bactericidal surfaces. However, not all such topography mediated bactericidal surfaces are necessarily cytocompatible thus underscoring the need for continued efforts for research in this area for developing antibacterial and yet cytocompatible surfaces for use in implantable biomedical applications. This mini-review provides a brief overview of the current strategies and challenges in the emerging field of topography mediated antibacterial surfaces. PMID:26372264

  15. Analysis of Multiple Manding Topographies during Functional Communication Training

    ERIC Educational Resources Information Center

    Harding, Jay W.; Wacker, David P.; Berg, Wendy K.; Winborn-Kemmerer, Lisa; Lee, John F.; Ibrahimovic, Muska

    2009-01-01

    We evaluated the effects of reinforcing multiple manding topographies during functional communication training (FCT) to decrease problem behavior for three preschool-age children. During Phase 1, a functional analysis identified conditions that maintained problem behavior for each child. During Phase 2, the children's parents taught them to…

  16. Geoid-to-topography ratios on Venus: A global perspective

    NASA Technical Reports Server (NTRS)

    Simons, Mark; Solomon, Sean C.

    1993-01-01

    Recently available spherical harmonic solutions for the geoid and topography of Venus are sufficiently high resolution that they can be used to address questions concerning the relationship between geoid and topography on a regional scale. We have approached this question by mapping the geoid-to-topography ratio (GTR) on a systematic global basis. For a given point on the surface, we consider the geoid and elevation values at all points on a gridded representation of those fields located within a specified distance of the reference point. From the set of paired values, we determine the correlation coefficient and the best-fitting straight line. The latter is the GTR at that position, and the former is a measure of the significance of the derived ratio. This procedure is then repeated for all points on the global grid, yielding maps of the GTR and the correlation coefficient. Unlike previous studies of the GRT on Venus, this apprach permits us to make an objective and systematic search for regions with anomalous GTR's as well as areas that do not demonstrate any strong correlation between geoid and topography. These maps can be updated regularly as new harmonic models of the Venus geoid are produced from new Magellan tracking data. This procedure permits the development of a global perspective on the relationship between GTR and venusian surface tectonics.

  17. Dental topography of platyrrhines and prosimians: convergence and contrasts.

    PubMed

    Winchester, Julia M; Boyer, Doug M; St Clair, Elizabeth M; Gosselin-Ildari, Ashley D; Cooke, Siobhán B; Ledogar, Justin A

    2014-01-01

    Dental topographic analysis is the quantitative assessment of shape of three-dimensional models of tooth crowns and component features. Molar topographic curvature, relief, and complexity correlate with aspects of feeding behavior in certain living primates, and have been employed to investigate dietary ecology in extant and extinct primate species. This study investigates whether dental topography correlates with diet among a diverse sample of living platyrrhines, and compares platyrrhine topography with that of prosimians. We sampled 111 lower second molars of 11 platyrrhine genera and 121 of 20 prosimian genera. For each tooth we calculated Dirichlet normal energy (DNE), relief index (RFI), and orientation patch count (OPCR), quantifying surface curvature, relief, and complexity respectively. Shearing ratios and quotients were also measured. Statistical analyses partitioned effects of diet and taxon on topography in platyrrhines alone and relative to prosimians. Discriminant function analyses assessed predictive diet models. Results indicate that platyrrhine dental topography correlates to dietary preference, and platyrrhine-only predictive models yield high rates of accuracy. The same is true for prosimians. Topographic variance is broadly similar among platyrrhines and prosimians. One exception is that platyrrhines display higher average relief and lower relief variance, possibly related to lower relative molar size and functional links between relief and tooth longevity distinct from curvature or complexity. Explicitly incorporating phylogenetic distance matrices into statistical analyses of the combined platyrrhine-prosimian sample results in loss of significance of dietary effects for OPCR and SQ, while greatly increasing dietary significance of RFI. PMID:24318939

  18. Enhanced surface hydrophobicity by coupling of surface polarity and topography

    E-print Network

    ) and microscopic (surface atomic polarity) characteristics for water in contact with a model solid surface basedEnhanced surface hydrophobicity by coupling of surface polarity and topography Nicolas on the structure of silica. We vary both the magnitude and direction of the solid surface polarity at the atomic

  19. Bed topography and the development of forced bed surface patches

    E-print Network

    Venditti, Jeremy G.

    Bed topography and the development of forced bed surface patches Peter A. Nelson,1 William E with the local flow and sediment transport fields to produce "forced patches," which are temporally stable areas of the mechanisms responsible for the formation of forced patches, we conducted a nearfield scale flume experiment

  20. Recent advances in engineering topography mediated antibacterial surfaces

    PubMed Central

    Hasan, Jafar

    2015-01-01

    The tendency of bacterial cells to adhere and colonize a material surface leading to biofilm formation is a fundamental challenge underlying many different applications including microbial infections associated with biomedical devices and products. Although, bacterial attachment to surfaces has been extensively studied in the past, the effect of surface topography on bacteria–material interactions has received little attention until more recently. We review the recent progress in surface topography based approaches for engineering antibacterial surfaces. Biomimicry of antibacterial surfaces in nature is a popular strategy. Whereas earlier endeavors in the field aimed at minimizing cell attachment, more recent efforts have focused on developing bactericidal surfaces. However, not all such topography mediated bactericidal surfaces are necessarily cytocompatible thus underscoring the need for continued efforts for research in this area for developing antibacterial and yet cytocompatible surfaces for use in implantable biomedical applications. This mini-review provides a brief overview of the current strategies and challenges in the emerging field of topography mediated antibacterial surfaces. PMID:26372264

  1. Tidal flow over threedimensional topography generates outofforcingplane harmonics

    E-print Network

    harmonics Benjamin King,1 H. P. Zhang,1 and Harry L. Swinney1 Received 10 March 2010; revised 30 April 2010 and mixing near rough topography in the ocean. Citation: King, B., H. P. Zhang, and H. L. Swinney (2010 the barotropic tide [Munk and Wunsch, 1998; Egbert and Ray, 2000]. The transfer of this barotropic energy from

  2. An anatomical and functional topography of human auditory cortical areas

    PubMed Central

    Moerel, Michelle; De Martino, Federico; Formisano, Elia

    2014-01-01

    While advances in magnetic resonance imaging (MRI) throughout the last decades have enabled the detailed anatomical and functional inspection of the human brain non-invasively, to date there is no consensus regarding the precise subdivision and topography of the areas forming the human auditory cortex. Here, we propose a topography of the human auditory areas based on insights on the anatomical and functional properties of human auditory areas as revealed by studies of cyto- and myelo-architecture and fMRI investigations at ultra-high magnetic field (7 Tesla). Importantly, we illustrate that—whereas a group-based approach to analyze functional (tonotopic) maps is appropriate to highlight the main tonotopic axis—the examination of tonotopic maps at single subject level is required to detail the topography of primary and non-primary areas that may be more variable across subjects. Furthermore, we show that considering multiple maps indicative of anatomical (i.e., myelination) as well as of functional properties (e.g., broadness of frequency tuning) is helpful in identifying auditory cortical areas in individual human brains. We propose and discuss a topography of areas that is consistent with old and recent anatomical post-mortem characterizations of the human auditory cortex and that may serve as a working model for neuroscience studies of auditory functions. PMID:25120426

  3. Oral Streptococci Biofilm Formation on Different Implant Surface Topographies

    PubMed Central

    Pita, Pedro Paulo Cardoso; Rodrigues, José Augusto; Ota-Tsuzuki, Claudia; Miato, Tatiane Ferreira; Zenobio, Elton G.; Giro, Gabriela; Figueiredo, Luciene C.; Gonçalves, Cristiane; Gehrke, Sergio A.; Cassoni, Alessandra; Shibli, Jamil Awad

    2015-01-01

    The establishment of the subgingival microbiota is dependent on successive colonization of the implant surface by bacterial species. Different implant surface topographies could influence the bacterial adsorption and therefore jeopardize the implant survival. This study evaluated the biofilm formation capacity of five oral streptococci species on two titanium surface topographies. In vitro biofilm formation was induced on 30 titanium discs divided in two groups: sandblasted acid-etched (SAE- n = 15) and as-machined (M- n = 15) surface. The specimens were immersed in sterilized whole human unstimulated saliva and then in fresh bacterial culture with five oral streptococci species: Streptococcus sanguinis, Streptococcus salivarius, Streptococcus mutans, Streptococcus sobrinus, and Streptococcus cricetus. The specimens were fixed and stained and the adsorbed dye was measured. Surface characterization was performed by atomic force and scanning electron microscopy. Surface and microbiologic data were analyzed by Student's t-test and two-way ANOVA, respectively (P < 0.05). S. cricetus, S. mutans, and S. sobrinus exhibited higher biofilm formation and no differences were observed between surfaces analyzed within each species (P > 0.05). S. sanguinis exhibited similar behavior to form biofilm on both implant surface topographies, while S. salivarius showed the lowest ability to form biofilm. It was concluded that biofilm formation on titanium surfaces depends on surface topography and species involved. PMID:26273590

  4. Tectonic velocities, dynamic topography, and relative sea level

    NASA Astrophysics Data System (ADS)

    Husson, L.; Conrad, C. P.

    2006-12-01

    The competition between ocean volume and dynamic topography in response to variable tectonic velocities can be captured by a simple, yet dynamically consistent, analysis based on the boundary layer theory. Our model reveals that short-lived changes in plate velocity (""tectonic pulses") have a negligible impact on dynamic topography. Tectonic velocities essentially mirror variations in mantle viscosity, but are not indicative of substantial modification of dynamic topography, which primarily reflects mass anomalies in the mantle. This implies that relative sea level is unlikely to be affected by "tectonic pulses" and also that observed tilting of cratonic margins couldn't result from a pulse of increased tectonic velocities. Thus, relative sea level is primarily controlled by the seafloor age distribution, although long-term (>100 myrs) changes in tectonic velocity will produce dynamic topography that reinforces sea level changes associated with changing ridge volume. These results can be related to present day plate motion and trench migration and mantle flow inferred from mantle tomography, in order to characterize the current variation -either dynamic or isostatic- of the volume of the oceans.

  5. Shape and Topography of Saturn's Satellites from Imaging Data

    NASA Astrophysics Data System (ADS)

    Gaskell, R. W.; Mastrodemos, N.; Rizk, B.

    2010-12-01

    Detailed global and local digital topographies of eight of Saturn's satellites are being constructed from ensembles of overlapping maplets which completely cover the visible surfaces. Each maplet is a digital representation of a piece of the surface topography and albedo constructed from imaging data with stereophotoclinometry. Multiple images projected onto the maplet provide brightness values at each pixel which are used in a least-squares estimation for slope and relative albedo. The slopes are then integrated to produce the topography solution. The central pixel of each maplet represents a control point, and the ensemble of these points is used in an estimation for their body-fixed locations, the rotational state of the body, and the position and attitude of the spacecraft. Applications of these data products include studies of cratering of icy bodies and the subsequent relaxation of the surface, while detailed shapes for the small, irregular satellites can be used to predict the surface gravity and local slope at high resolution. For a larger satellite, a precise shape determination is important because often the shape was frozen in when the body was in a different rotational state. This enables an analysis of the rotational and orbital histories of these bodies. The high resolution topography yields surface roughness, slopes, overall elevation variations, and fractal character of the surface.

  6. Two Notions Contrasted: 'Logical Geography' and 'Logical Topography'

    E-print Network

    Sloman, Aaron

    that the distinction is of any significance, but I've altered my text to fit what he wrote.) APOLOGETIC NOTE 1 #12;On 4. (Probably what Ryle meant by the term.) Logical topography Features of the portion of reality, or types of portions of reality, related to a given set of concepts, where the reality may be capable of being divided

  7. Product layout induced topography effects on intrafield levelling

    NASA Astrophysics Data System (ADS)

    Simiz, J.-G.; Hasan, T.; Staals, F.; Le-Gratiet, B.; Tel, W. T.; Prentice, C.; Tishchenko, A.

    2015-09-01

    With continuing dimension shrinkage using the TWINSCAN NXT:1950i scanner on the 28nm node and beyond, the imaging depth of focus (DOF) becomes more critical. Focus budget breakdown studies [Ref 2, 5] show that even though the intrafield component stays the same, it becomes a larger relative percentage of the overall DOF. Process induced topography along with reduced Process Window can lead to yield limitations and defectivity issues on the wafer. In a previous paper, the feasibility of anticipating the scanner levelling measurements (Level Sensor, Agile and Topography) has been shown [1]. This model, built using a multiple variable analysis (PLS: Partial Least Square regression) and GDS densities at different layers showed prediction capabilities of the scanner topography readings up to 0.78 Q² (the equivalent of R² for expected prediction). Using this model, care areas can be defined as parts of the field that cannot be seen nor corrected by the scanner, which can lead to local DOF shrinkage and printing issues. This paper will investigate the link between the care areas and the intrafield focus that can be seen at the wafer level, using offline topography measurements as a reference. Some improvements made on the model are also presented.

  8. EAARL topography-Potato Creek watershed, Georgia, 2010

    USGS Publications Warehouse

    Bonisteel-Cormier, J.M.; Nayegandhi, Amar; Fredericks, Xan; Jones, J.W.; Wright, C.W.; Brock, J.C.; Nagle, D.B.

    2011-01-01

    This DVD contains lidar-derived first-surface (FS) and bare-earth (BE) topography GIS datasets of a portion of the Potato Creek watershed in the Apalachicola-Chattahoochee-Flint River basin, Georgia. These datasets were acquired on February 27, 2010.

  9. Estimating the Bedrock Topography of the Gangotri Glacier in India

    NASA Astrophysics Data System (ADS)

    Gantayat, P.; Kulkarni, A. V.; Srinivasan, J.

    2014-12-01

    Himalayan glaciers make useful contribution in the runoff of many rivers in South Asia. Knowledge of depth and bottom topography is useful in understanding future distribution of glaciers; the evolution of periglacial morphology and the subglacial drainage pattern. In this investigation, we have estimated the bedrock topography of Gangotri glacier which is located in the Indian part of Central Himalayas. The Gangotri glacier is one of the largest glaciers and has an areal extent of around 140 Km2.It is considered traditionally to be the source of River Ganges which is one of the main source of water for a large population living in the Indo-Gangetic plains. The bottom topography was estimated using the ice thickness and surface elevation. Ice thickness was estimated using an ice flow model, surface velocities and slope. Surface velocities were estimated using sub-pixel correlation of Landsat TM and ETM+ imagery for the years 2009 and 2010. The velocities that were estimated ranged from 14-85 m/a in the upper reaches to 20-30 m/a near the snout. The surface elevation was estimated using ASTER DEM and varied from ~4100 m near the snout to ~6600 m in the upper reaches. The combination of surface elevation and depth was used to estimate spatial distribution of bottom topography. The estimated bottom topography varies from ~3900 to 6100 masl and also shows number of depressions as deep as 50-100m. These depressions are potential sites for the formation of periglacial lakes, influencing future retreat and security of the region.

  10. Shape and topography corrections for planetary nuclear spectroscopy

    NASA Astrophysics Data System (ADS)

    Prettyman, Thomas H.; Hendricks, John S.

    2015-11-01

    The elemental composition of planetary surfaces can be determined using gamma ray and neutron spectroscopy. Most planetary bodies for which nuclear spectroscopy data have been acquired are round, and simple, analytic corrections for measurement geometry can be applied; however, recent measurements of the irregular asteroid 4 Vesta by Dawn required more detailed corrections using a shape model (Prettyman et al., Science 2012). In addition, subtle artifacts of topography have been observed in low altitude measurements of lunar craters, with potential implications for polar hydrogen content (Eke et al., JGR 2015). To explore shape and topography effects, we have updated the general-purpose Monte Carlo radiation transport code MCNPX to include a polygonal shape model (Prettyman and Hendricks, LPSC 2015). The shape model is fully integrated with the code’s 3D combinatorial geometry modules. A voxel-based acceleration algorithm enables fast ray-intersection calculations needed for Monte Carlo. As modified, MCNPX can model neutron and gamma ray transport within natural surfaces using global and/or regional shape/topography data (e.g. from photogrammetry and laser altimetry). We are using MCNPX to explore the effect of small-scale roughness, regional-, and global-topography for asteroids, comets and close-up measurements of high-relief features on larger bodies, such as the lunar surface. MCNPX can characterize basic effects on measurements by an orbiting spectrometer such as 1) the angular distribution of emitted particles, 2) shielding of galactic cosmic rays by surrounding terrain and 3) re-entrant scattering. In some cases, re-entrant scattering can be ignored, leading to a fast ray-tracing model that treats effects 1 and 2. The algorithm is applied to forward modeling and spatial deconvolution of epithermal neutron data acquired at Vesta. Analyses of shape/topography effects and correction strategies are presented for Vesta, selected small bodies and cratered planetary surfaces.

  11. The effects of abrupt topography on plankton dynamics.

    PubMed

    Zavala Sansón, L; Provenzale, A

    2009-12-01

    Plankton population dynamics in the upper layer of the ocean depends on upwelling processes that bring nutrients from deeper waters. In turn, these depend on the structure of the vertical velocity field. In coastal areas and in oceanic regions characterized by the presence of strong submarine topographic features, the variable bottom topography induces significant effects on vertical velocities and upwelling/downwelling patterns. As a consequence, large plankton and fish abundances are frequently observed above seamounts, canyons and steep continental shelves. In this work, the dynamics of an NPZ (nutrient-phytoplankton-zooplankton) system is numerically studied by coupling the ecosystem model with a quasi two-dimensional (2D) fluid model with topography. At variance with classical 2D approaches, this formulation allows for an explicit expression of the vertical motions produced when fluid columns are squeezed and stretched as they experience changes of depth. Thus, input or output of nutrients at the surface are associated with fluid motion over the bottom topography. We examine the dynamics of a cyclonic vortex over two basic topographies: a steep escarpment and a submarine mountain. We show that plankton abundance over the escarpment is modulated by the passing of topographic Rossby waves, generated by the vortex-topography interaction. In such configuration, advection effects driven by the flow over the escarpment are of limited relevance for the dynamics of biological fields. By contrast, we find that the flow resulting from the interaction of a vortex with a seamount is sufficiently strong and persistent to allow for a remarkable increase of nutrients, and a corresponding enhancement of phytoplankton and zooplankton concentrations. Over the seamount, advection effects associated with trapped flow perturbations around the summit play an essential role. PMID:19737575

  12. Radiation and dissipation of internal waves generated by geostrophic motions impinging on small-scale topography

    E-print Network

    Nikurashin, Maxim (Maxim Anatolevich)

    2009-01-01

    Observations and inverse models suggest that small-scale turbulent mixing is enhanced in the Southern Ocean in regions above rough topography. The enhancement extends 1 km above the topography suggesting that mixing is ...

  13. In-situ Observation of Switchable Nanoscale Topography for Y-Shaped

    E-print Network

    Natelson, Douglas

    In-situ Observation of Switchable Nanoscale Topography for Y-Shaped Binary Brushes in Fluids Yen network-like surface topography formed by coexisting stretched soluble PAA arms and collapsed insoluble PS

  14. Topography and physiology of ascending streams in the auditory tectothalamic pathway

    E-print Network

    Sherman, S. Murray

    Topography and physiology of ascending streams in the auditory tectothalamic pathway Charles C. Lee in response to photo- stimulation in the IC with caged glutamate were used to map the topography of excitatory

  15. Maximum a Posteriori Models for Cortical Modeling: Feature Detectors, Topography and Modularity

    E-print Network

    Weber, Cornelius

    Maximum a Posteriori Models for Cortical Modeling: Feature Detectors, Topography and Modularity Modeling: Feature Detectors, Topography and Modularity PhD Thesis by Cornelius Weber, Berlin, July 31, 2000

  16. Tectonic geomorphology and hydrocarbon induced topography of the Mid-Channel Anticline, Santa Barbara Basin, California

    E-print Network

    Keller, Ed

    Tectonic geomorphology and hydrocarbon induced topography of the Mid-Channel Anticline, Santa The geomorphology of the western sector of the Mid-Channel Anticline (MCA), Santa Barbara, southern California. Keywords: Active folding; Tectonic geomorphology; Hydrocarbon induced topography 1. Introduction

  17. Comparison of SRTM Topography to USGS and High Resolution Laser Altimetry Topography: Case Studies From the Oregon Coast Range

    NASA Astrophysics Data System (ADS)

    Dietrich, W. E.; Stock, J. D.; Allen, D.; Beluggi, D.; Montgomery, D. R.; Roering, J. J.

    2001-12-01

    The Shuttle Radar Topography mission (SRTM) acquired topographic data for the non-polar regions of earth at a nominal 30-m resolution. This horizontal resolution is dramatically higher than previous ~1 km data, and is likely to be used by a broad cross-section of the earth sciences community for detailed modeling of surface and coupled surface-atmospheric models. These users will need to know how SRTM topography compares with field-scale (e.g., 1-2 m) topography. We compare SRTM 30-m data to 3 sites in the forested steeplands of the Oregon Coast Range where we have acquired 2-3 m spaced topography using laser altimetry and total station surveys over areas from 2-6 km2. At each site, we have field-checked the laser altimetry with ground reconnaissance and measurements, and have identified vegetation cover. In addition, we compare the SRTM data to the existing public access data from the USGS 10- and 30-m data. We compare the coarser resolution data to high resolution data, and to re-gridded versions of the high resolution data for the following landscape metrics: 1) mean slope, 2) local slope distribution, 3) drainage density at a given area threshold, 4) relief as a function of area, 5) link magnitude distribution, and 6) slope versus area for the valley network. We also compare individual hillslope and river profiles by comparing rms error of the coarser data to fine resolution topography, and evaluate the planform errors in the coarser valley network. Our comparisons should guide user's interpretation of SRTM data where ground-truthing data are absent.

  18. Wafer Topography-Aware Optical Proximity Correction for Better DOF Margin and CD Control

    E-print Network

    Kahng, Andrew B.

    Wafer Topography-Aware Optical Proximity Correction for Better DOF Margin and CD Control Puneet are oblivious to the predictable nature of focus variation arising from wafer topography. As a result, designers that is generated by CMP simulation. The wafer topography variations result in local defocus, which we explicitly

  19. The Direct Breaking of Internal Waves at Steep1 Topography2

    E-print Network

    Klymak, Jody M.

    1 The Direct Breaking of Internal Waves at Steep1 Topography2 Jody M. Klymak, Sonya Legg, Matthew H. Alford, Maarten Buijsman,3 Robert Pinkel and Jonathan D. Nash4 5 Abstract6 7 Internal waves are often steep "supercritical" topography (i.e. topography that is steeper than internal wave energy13

  20. Subcellular Topography of Visually Driven Dendritic Activity in the Vertebrate Visual System

    E-print Network

    Engert, Florian

    Neuron Article Subcellular Topography of Visually Driven Dendritic Activity in the Vertebrate+ signals are heterogeneously distributed and topographi- cally biased across a developing dendritic tree to stimulus space. A possible topography of dendritic Ca2+ signaling may reflect the anatomical map

  1. Dynamic topography and anomalously negative residual depth of the Argentine Basin G.E. Shephard a,

    E-print Network

    Liu, Lijun

    GR letter Dynamic topography and anomalously negative residual depth of the Argentine Basin G Handling Editor: A. Aitken Keywords: Dynamic topography Residual basement depth Geodynamic modeling Argentine Basin Subduction Plate tectonics A substantial portion of Earth's topography is known to be caused

  2. Double lateral shearing interferometer for the quantitative measurement of tear film topography

    E-print Network

    Dainty, Chris

    Double lateral shearing interferometer for the quantitative measurement of tear film topography topography features: postblink tear undulation, tear breakup, eyelid-produced bumps and ridges, bubbles. A more suitable technique to study the tear topography was proposed by Licznerski et al.,31 where

  3. Corneal Topography: A review, new ANSI standards and problems to solve Stanley A. Klein

    E-print Network

    Klein, Stanley

    Corneal Topography: A review, new ANSI standards and problems to solve Stanley A. Klein School@spectacle.berkeley.edu Abstract: This review of corneal topography has three sections: 1. a brief introduction to how corneal topography instruments work. A quantitative comparison of the relative accuracy of slope based and position

  4. Gravity-Driven flow of evaporating thin liquid films over substrates with topography

    E-print Network

    Jimack, Peter

    Gravity-Driven flow of evaporating thin liquid films over substrates with topography Gaskell, P. Abstract This paper considers gravity-driven flow of thin liquid films over substrates with topography of gravity-driven flow of thin liquid films over well defined topography, as indicated in Figure 1, in which

  5. JUSTIFICATION OF THE SHALLOW WATER LIMIT FOR A RIGID LID FLOW WITH BOTTOM TOPOGRAPHY

    E-print Network

    Oliver, Marcel

    JUSTIFICATION OF THE SHALLOW WATER LIMIT FOR A RIGID LID FLOW WITH BOTTOM TOPOGRAPHY MARCEL OLIVER with bottom topography. We prove an a priori estimate in the Sobolev space H m for m #21; 3 which shows and the magnitude of the initial data in H m , the gradient of the bottom topography in H m+1 , and the aspect ratio

  6. Some approximate Godunov schemes to compute shallow-water equations with topography

    E-print Network

    Gallouët, Thierry

    Some approximate Godunov schemes to compute shallow-water equations with topography Thierry the computation of shallow-water equations with topography by Finite Volume methods, in a one are based on a discretisation of the topography by a piecewise function constant on each cell of the mesh

  7. City-wide relationships between green spaces, urban land use and topography

    E-print Network

    Queensland, University of

    City-wide relationships between green spaces, urban land use and topography Richard G. Davies in urban form and topography. The total area of buildings and length of the road network are equally strong-cover. Topography. Urban form Urban Ecosyst (2008) 11:269­287 DOI 10.1007/s11252-008-0062-y R. G. Davies :O. Barbosa

  8. Reflectivity and topography of cells grown on glass-coverslips measured with

    E-print Network

    Ovryn, Ben

    Reflectivity and topography of cells grown on glass-coverslips measured with phase-shifted laser the topography and reflection from calibration spheres and from stress fibers and adhesions in both fixed membrane topography," Cell. Biochem. Bio- phys. 1(3), 391­414 (2004). 11. J. T. Groves, R. Parthasarathy

  9. Cortical Projection Topography of the Human Splenium: Hemispheric Asymmetry and Individual Differences

    E-print Network

    Gazzaniga, Michael

    Cortical Projection Topography of the Human Splenium: Hemispheric Asymmetry and Individual topography of the human splenium. Homotopic and heterotopic connections were revealed between the splenium difficult to trace the cortical projection topographies of long white matter fiber tracts of the human brain

  10. Separating the effects of topography and composition in the Clementine UVVIS data set

    E-print Network

    Withers, Paul

    Separating the effects of topography and composition in the Clementine UVVIS data set Paul Withers - 10 May 1999 Remote Sensing of Planetary Surfaces Topography and surface composition both affect corrected for topography are generated for each of the five images. The technique is evaluated by comparing

  11. ForPeerReview Number and Topography of Cones, Rods and Optic Nerve Axons

    E-print Network

    Finlay, Barbara L.

    ForPeerReview Number and Topography of Cones, Rods and Optic Nerve Axons in New and Old World nerve Visual Neuroscience #12;ForPeerReview 1 Number and Topography of Cones, Rods and Optic Nerve AxonsPeerReview 2 Number and Topography of Cones, Rods and Optic Nerve Axons in New and Old World Primates Abstract

  12. The Effect of Topography on Storm-Track Intensity in a Relatively Simple General Circulation Model

    E-print Network

    Son, Seok-Woo

    The Effect of Topography on Storm-Track Intensity in a Relatively Simple General Circulation Model The effect of topography on storm-track intensity is examined with a set of primitive equation model flow impinging on the topography. If the background flow consists of a weak double jet, higher

  13. Under consideration for publication in J. Fluid Mech. 1 Nonlinear dynamics over rough topography

    E-print Network

    Vanneste, Jacques

    Under consideration for publication in J. Fluid Mech. 1 Nonlinear dynamics over rough topography-dimensional, pe- riodic or random, small-scale topography is investigated using an asymptotic approach. Averaged (or homogenised) evolution equations which account for the flow-topography in- teraction are derived

  14. Flow-topography interactions in the northern California Current System observed from geostationary satellite data

    E-print Network

    Balasubramanian, Ravi

    Flow-topography interactions in the northern California Current System observed from geostationary: Castelao, R. M., J. A. Barth, and T. P. Mavor (2005), Flow-topography interactions in the northern in regions of simple topography, to the north of Newport (44.65°N). Recently, however, interest in regions

  15. Topography-Correlated Confocal Raman Microscopy with Cylindrical Vector Beams for Probing Nanoscale Structural Order

    E-print Network

    Schreiber, Frank

    Topography-Correlated Confocal Raman Microscopy with Cylindrical Vector Beams for Probing Nanoscale, such as radially or azimuthally polarized doughnut beams, are combined with topography studies of pentacene thin in the mirror focus and kept within a nanometer distance from the surface to probe the topography using shear

  16. Control of the ocean circulation by boundaries and topography P.B. Rhines

    E-print Network

    Control of the ocean circulation by boundaries and topography P.B. Rhines University of Washington enstrophy and zonal momentum, which no longer hold in the ocean basins or with uneven topography. Since circulation. Generalizations to stratified oceans and oceans with continental-rise bottom topography are given

  17. Leveraging XSEDE HPC resources to address computational challenges with high-resolution topography

    E-print Network

    Tarboton, David

    Leveraging XSEDE HPC resources to address computational challenges with high-resolution topography topography data. These web services make results from community software packages and other cyberinfrastructure-based applications available to the wider earth sciences community via the OpenTopography Facility

  18. Exact three-dimensional spectral solution to surface-groundwater interactions with arbitrary surface topography

    E-print Network

    surface topography Anders Wo¨rman,1 Aaron I. Packman,2 Lars Marklund,1 Judson W. Harvey,3 and Susa H. [1] It has been long known that land surface topography governs both groundwater flow patterns that the surface topography can be separated in a Fourier-series spectrum that provides an exact solution

  19. Tectonic velocities, dynamic topography, and relative sea level Laurent Husson1,2

    E-print Network

    Conrad, Clint

    Tectonic velocities, dynamic topography, and relative sea level Laurent Husson1,2 and Clinton P] A simple dynamic model based on boundary layer theory shows that dynamic topography is unlikely to vary of dynamic topography, which primarily reflects mass anomalies in the mantle. This implies that relative sea

  20. Gravity/Topography Transfer Function and Isostatic Geoid Anomalies (Copyright 2002, David T. Sandwell)

    E-print Network

    Sandwell, David T.

    1 Gravity/Topography Transfer Function and Isostatic Geoid Anomalies (Copyright 2002, David T to develop a linear relationship between gravity and topography. This relationship can be used in a variety of ways. (1) If both the topography and gravity are measured over an area that is several times greater

  1. ERRORS IN VIKING LANDER ATMOSPHERIC PROFILES DISCOVERED USING MOLA TOPOGRAPHY. Paul Withers1

    E-print Network

    Withers, Paul

    ERRORS IN VIKING LANDER ATMOSPHERIC PROFILES DISCOVERED USING MOLA TOPOGRAPHY. Paul Withers1 , R. D above the spatially-varying martian topography, were used to constrain the reconstructed trajectory of martian topography pro- vided by the laser altimeter (MOLA) aboard the Mars Global Surveyor spacecraft

  2. SYNTHETIC APERTURE INVERSION FOR NON-FLAT TOPOGRAPHY C. J. Nolan *

    E-print Network

    Cheney, Margaret

    SYNTHETIC APERTURE INVERSION FOR NON-FLAT TOPOGRAPHY C. J. Nolan * , M. Cheney ** * Department topography is known but not necessarily flat. We consider two cases, corresponding to the degree and the topography to avoid artifacts. We show that the algorithm correctly reproduces certain features of the scene

  3. Coremantle boundary topography as a possible constraint on lower mantle chemistry and dynamics

    E-print Network

    Rhoads, James

    Core­mantle boundary topography as a possible constraint on lower mantle chemistry and dynamics November 2009 Editor: Y. Ricard Keywords: mantle convection core­mantle boundary CMB topography), each of which uniquely affects the topography on Earth's core­mantle boundary (CMB). The thermochemical

  4. Topography, relief, and TRMM-derived rainfall variations along the Bodo Bookhagen1,2

    E-print Network

    Bookhagen, Bodo

    Topography, relief, and TRMM-derived rainfall variations along the Himalaya Bodo Bookhagen1. To investigate the influence of topography and relief on rainfall generation and resultant erosion, we processed distribution of rainfall and (2) the large-scale relationships between topography, relief, and rainfall

  5. Central-Upwind Scheme for Shallow Water Equations with Discontinuous Bottom Topography

    E-print Network

    Chertock, Alina

    Central-Upwind Scheme for Shallow Water Equations with Discontinuous Bottom Topography Andrew are achieved, in particular, by using continuous piecewise linear interpolation of the bottom topography function. However, when the bottom function is discontinuous or a model with a moving bottom topography

  6. Dynamic topography and anomalously negative residual depth of the Argentine Basin G.E. Shephard a,

    E-print Network

    Müller, Dietmar

    GR letter Dynamic topography and anomalously negative residual depth of the Argentine Basin G: A. Aitken Keywords: Dynamic topography Residual basement depth Geodynamic modeling Argentine Basin Subduction Plate tectonics A substantial portion of Earth's topography is known to be caused by the viscous

  7. Controls of climate, topography, vegetation and lithology on drainage density extracted from high resolution topography

    NASA Astrophysics Data System (ADS)

    Sangireddy, H.; Carothers, R. A.; Passalacqua, P.; Stark, C. P.

    2014-12-01

    Drainage density is a useful topographic metric that varies as a function of geomorphic processes and that serves to quantify links with topography, climate, vegetation, and lithology. Here we analyze 101 sub-basins across thirteen states in the USA using high-resolution digital terrain models (DTMs) in combination with data on the spatial variation of precipitation, soil, geology, and land cover. We test the following hypotheses: (1) Drainage density carries strong, codependent signatures of rainfall variability, soil type, and topographic relief; (2) Drainage density reflects the extent of landscape dissection on the sub-catchment scale and the subsequent processes of vegetation recovery and gullying.We employ a dimensionless drainage density (Ddd) metric defined as the ratio of likely channelized pixels in a basin to its total number of pixels, and map this metric across meter-resolution lidar DTMs using GeoNet [Passalacqua et al., 2010]. We assess the resolution-dependent scaling of Ddd and observe that it is a much weaker scaling function of DTM resolution than the dimensional formulation of drainage density (Dg), which is classically defined as the ratio of total channel length to total basin area.In order to characterize the correlation structure of drainage density with climatic parameters such as mean annual precipitation (MAP), we use a Gaussian mixture model and identify two sub-groups of landscapes that display different correlations. We observe that Ddd and MAP are negatively correlated in arid and semi-arid environments and positively correlated in humid environments. The transition occurs at a MAP around 900-1000mm/yr and coincides with the maximum observed values of soil thickness and available water content. Landscape relief has a negative correlation with Ddd in arid environments while the correlation is positive in humid climates. We discuss the implication of our results for understanding eco-geomorphic processes and for modeling landscape evolution.References:Passalacqua, P., Do Trung, T., Foufoula-Georgiou, E., Sapiro, G., & Dietrich, W. E. (2010). A geometric framework for channel network extraction from lidar: Nonlinear diffusion and geodesic paths. Journal of Geophysical Research: Earth Surface (2003-2012), 115(F1).

  8. Irregular topography at the Earth's inner core boundary.

    PubMed

    Dai, Zhiyang; Wang, Wei; Wen, Lianxing

    2012-05-15

    Compressional seismic wave reflected off the Earth's inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth's ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4-8 km with a lateral length scale of 2-4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable. PMID:22547788

  9. Waves in the OH emissive layer: photogrammetry and topography.

    PubMed

    Hersé, M; Moreels, G; Clairemidi, J

    1980-02-01

    The waves in the OH emissive layer, which appear on photographs of the sky in the near IR taken with large aperture cameras, are distorted by atmospheric refraction and by a perspective effect. Two methods have been developed to allow restitution of the topography of the waves in a simple way. In the first method a grid is computed, which is superimposed on an enlargement of the original 24 x 36-mm negative frame. In the second method the image is projected on an aspherical surface that is tilted with respect to the enlarger beam. The topography of a wave display, photographed from the Pic du Midi Observatory during the night of 19-20 November 1976, is obtained using both methods. The photometric aspect of the photographs may be interpreted under the simple assumption that the emissive layer has a constant thickness and is ruffled like the wavy surface of the sea. PMID:20216855

  10. Defect Analysis in Crystals using X-ray Topography

    SciTech Connect

    Raghothamachar,B.; Dhanaraj, G.; Bai, J.; Dudley, M.

    2006-01-01

    A brief review of X-ray topography - a nondestructive method for direct observation and characterization of defects in single crystals - is presented here. The origin and development of this characterization method and the different techniques derived from it are described. Emphasis is placed on synchrotron X-ray topography and its application in studying various crystal imperfections. Mechanisms of contrast formation on X-ray topographs are discussed, with emphasis on contrast associated with dislocations. Determination of Burgers vectors and line directions of dislocations from analysis of X-ray topographs is explained. Contrast from inclusions is illustrated, and their differentiation from dislocations is demonstrated with the aid of simulated topographs. Contrast arising from the deformation fields associated with cracks is also briefly covered.

  11. Ice sheet topography from retracked ERS-1 altimetry

    NASA Technical Reports Server (NTRS)

    Zwally, H. Jay; Brenner, Anita C.; Dimarzio, John; Seiss, Timothy

    1994-01-01

    An objective of the ERS-1 radar altimeter is to measure the surface topography of the polar ice sheets to a precision on the order of a meter. ERS-1 Waveform Altimeter Product (WAP) data was corrected for several processing errors. A range correction from the WAP waveforms, using the multiparameter retracking algorithm to account for range tracking limitations inherent to radar altimetry, was derived. From crossover analysis, the resulting precision is shown to be about 2.1 m in ocean mode and 2.2 m in ice mode. A topography map, produced with 23 days of corrected data, shows details of the western part of west Antarctic ice sheet and part of the Ross ice shelf including ice divides, ice stream boundaries, and ice shelf grounding lines.

  12. Geophysical, petrological and mineral physics constraints on Earth's surface topography

    NASA Astrophysics Data System (ADS)

    Guerri, Mattia; Cammarano, Fabio; Tackley, Paul J.

    2015-04-01

    Earth's surface topography is controlled by isostatically compensated density variations within the lithosphere, but dynamic topography - i.e. the topography due to adjustment of surface to mantle convection - is an important component, specially at a global scale. In order to separate these two components it is fundamental to estimate crustal and mantle density structure and rheological properties. Usually, crustal density is constrained from interpretation of available seismic data (mostly VP profiles) based on empirical relationships such those in Brocher [2005]. Mantle density structure is inferred from seismic tomography models. Constant coefficients are used to interpret seismic velocity anomalies in density anomalies. These simplified methods are unable to model the effects that pressure and temperature variations have on mineralogical assemblage and physical properties. Our approach is based on a multidisciplinary method that involves geophysical observables, mineral physics constraints, and petrological data. Mantle density is based on the thermal interpretation of global seismic tomography models assuming various compositional structures, as in Cammarano et al. [2011]. We further constrain the top 150 km by including heat-flow data and considering the thermal evolution of the oceanic lithosphere. Crustal density is calculated as in Guerri and Cammarano [2015] performing thermodynamic modeling of various average chemical compositions proposed for the crust. The modeling, performed with the code PerpleX [Connolly, 2005], relies on the thermodynamic dataset from Holland and Powell [1998]. Compressional waves velocity and crustal layers thickness from the model CRUST 1.0 [Laske et al., 2013] offer additional constrains. The resulting lithospheric density models are tested against gravity (GOCE) data. Various crustal and mantle density models have been tested in order to ascertain the effects that uncertainties in the estimate of those features have on the modeled topography. We also test several viscosity models, either radially symmetric, the V1 profile from Mitrovica and Forte [2004], or more complex laterally varying structures. All the property fields are expanded in spherical harmonics, until degree 24, and implemented in the code StagYY [Tackley, 2008] to perform mantle instantaneous flow modeling and compute surface topography and gravitational field. Our results show the importance of constraining the crustal and mantle density structure relying on a multidisciplinary approach that involves experimentally robust thermodynamic datasets. Crustal density field has a strong effect on the isostatic component of topography. The models that we test, CRUST 1.0 and those in Guerri and Cammarano [2015], produce strong differences in the computed isostatic topography, in the range ±600 m. For the lithospheric mantle, relying on experimentally robust material properties constraints is necessary to infer a reliable density model that takes into account chemical heterogeneities. This approach is also fundamental to correctly interpret seismic models in temperature, a crucial parameter, necessary to determine the lithosphere-asthenosphere boundary, where static effects on topography leave place to dynamic ones. The comparison between results obtained with different viscosity fields, either radially symmetric or vertically and laterally varying, shows how lateral viscosity variations affect the results, in particular the modeled geoid, at different wavelengths. References: Brocher, T. M. (2005), Empirical Relations between Elastic Wavespeeds and Density in the Earth's Crust, Bulletin of the Seismological Society of America, 95(6), 2081-2092. Cammarano, F., P. J. Tackley, and L. Boschi (2011), Seismic, petrological and geodynamical constraints on thermal and compositional structure of the upper mantle: global thermochemical models, Geophys. J. Int. Connolly, J. A. D. (2005), Computation of phase equilibria by linear programming: A tool for geodynamic modeling and its application to subduction zone decarbonation, Earth and

  13. Role of membrane stresses in the support of planetary topography

    NASA Technical Reports Server (NTRS)

    Turcotte, D. L.; Willemann, R. J.; Haxby, W. F.; Norberry, J.

    1981-01-01

    The role of membrane stresses and bending stresses in supporting topographic loads on planetary elastic lithospheres is examined. A dimensionless parameter is introduced in order to determine the ability of a spherical shell to support loads through membrane stresses. It is determined that when this parameter is large, membrane stresses can fully support topographic loads with flexure, and when it is small the influence of the membrane stresses can be neglected. Equations governing the behavior of a spherical shell are solved for a topographic load expressed in terms of spherical harmonics, and spherical harmonic expansions of the measured gravity and topography for Mars and the moon are compared with the theory. It is concluded that membrane stresses play an important role in the support of topographic loads on the moon and Mars. The correlation of observed gravitational potential anomalies with the topography on Mars is explained by membrane stresses in the elastic lithosphere.

  14. Method and Apparatus for Creating a Topography at a Surface

    DOEpatents

    Adams, David P. (Albuquerque, NM); Sinclair, Michael B. (Albuquerque, NM); Mayer, Thomas M. (Albuquerque, NM); Vasile, Michael J. (Albuquerque, NM); Sweatt, William C. (Albuquerque, NM)

    2008-11-11

    Methods and apparatus whereby an optical interferometer is utilized to monitor and provide feedback control to an integrated energetic particle column, to create desired topographies, including the depth, shape and/or roughness of features, at a surface of a specimen. Energetic particle columns can direct energetic species including, ions, photons and/or neutral particles to a surface to create features having in-plane dimensions on the order of 1 micron, and a height or depth on the order of 1 nanometer. Energetic processes can include subtractive processes such as sputtering, ablation, focused ion beam milling and, additive processes, such as energetic beam induced chemical vapor deposition. The integration of interferometric methods with processing by energetic species offers the ability to create desired topographies at surfaces, including planar and curved shapes.

  15. Stresses in a submarine topography under ocean waves

    SciTech Connect

    Mei, C.C.; McTigue, D.F.

    1984-09-01

    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, and obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular, the dynamic pore pressure and the combined static and dynamic effective stresses are presented.

  16. Stresses in a submarine topography under ocean waves

    SciTech Connect

    Mei, C.C.; McTigue, D.F.

    1984-01-01

    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, to obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular the dynamic pore pressure and the combined static and dynamic effective stresses are presented. 10 references, 11 figures.

  17. Irregular topography at the Earth’s inner core boundary

    PubMed Central

    Dai, Zhiyang; Wang, Wei; Wen, Lianxing

    2012-01-01

    Compressional seismic wave reflected off the Earth’s inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth’s ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4–8 km with a lateral length scale of 2–4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable. PMID:22547788

  18. Topography, relief, climate and glaciers: a global prespective

    NASA Astrophysics Data System (ADS)

    Champagnac, Jean-Daniel; Valla, Pierre; Herman, fred

    2014-05-01

    The examination of the relationship between Earth's topography and present and past climate (i.e. long-term elevation of glaciers Equilibrium Line Altitude) reveals that the elevation of mountain ranges may be limited or controlled by glaciations. This is of prime importance, because glacial condition would lead to a limit the mountain development, hence the accumulation of gravitational energy and prevent the development of further glacial conditions as well as setting the erosion in (peri)glacial environments. This study examines the relationships between topography and the global Equilibrium Line Altitude of alpine glaciers around the world (long term snowline, i.e. the altitude where the ice mass balance is null). Two main observations can be drawn: 1) The distance between the (averaged and maximum) topography, and the ELA decreases pole ward the poles, and even become reversed (mean elevation above to ELA) at high latitude. Correlatively, the elevation of very large portion of land at mid-latitude cannot be related to glaciations, simply because it was never glaciated (large distance between topography and long-term mean ELA). The maximum distance between the ELA and the topography is greater close to the equator and decreases poleward. In absence of glacial and periglacial erosion, this trend cannot have its origin in glacial and periglacial processes. Moreover, the ELA elevation shows a significant (1000 - 1500m) depression in the intertropical zone. This depression of the ELA is not reflected at all in the topography. 2) The distribution of relief on Earth, if normalized by the mean elevation of mountain ranges (as a proxy for available space to create relief) shows a latitudinal band of greater relief between 40° and 60° (or between ELA of 500m to 2500m a.s.l.). This mid-latitude relatively greater relief challenges the straightforward relationship between glaciations, erosion and topography. Oppositely, it suggests that glacier may be more efficient agent in temperate area, with important amplitude between glacial and interglacial climate. This is consistent with the view of a very variable glacier erodibility that can erode and protect the landscape, as well as with studies documenting a bimodal location of the preferred glacial erosion, at relatively high elevation (around the long-term ELA), and at much lower elevation (close to the glacial maximum lower reaches), thanks to efficient water lubrication of the glacier bases that greatly enhance the sliding velocity. These findings show that the relation between the mountain topography and the long term snowline is not as straightforward as previously proposed. Beside the role of tectonic forcing highlighted by several authors, the importance of the glacial erosion appears to be crucial at mid latitude, but more complex at both high and low latitude. Moreover, the relief at mid latitude appears to be higher, hence suggesting a positive correlation between relief and topographic control of glacier on the landscape.

  19. The Formation of Non-Zonal Jets over Sloped Topography

    NASA Astrophysics Data System (ADS)

    Boland, E.; Thompson, A. F.; Shuckburgh, E.; Haynes, P. H.

    2012-04-01

    We present the results of an investigation into the effect of a spatially uniform slope in bottom topography in a quasi-geostrophic, doubly periodic, two-layer model. A slope in the meridional direction results in the enhancement of the 'beta' effect, producing zonal jets, familiar from many previous studies. The novel aspect of this investigation is that the bottom slope has arbitrary orientation. Jets continue to form but they are non-zonal and tilted relative to layer-wise potential vorticity gradients. We show that these non-zonal jets follow the barotropic potential vorticity gradient, and we find that eddy energies are larger when the barotropic potential vorticity gradient is aligned with the direction of the shear in the system. The tilted jets are also demonstrated to be weaker barriers to transport than their zonal counterparts using an effective diffusivity diagnostic. These results are shown to be independent of the ratio of layer depths and to carry over to more complicated topographies containing slopes. We also interpret these results in the light of linear Rossby wave theory, showing the extent to which the jet orientation can be explained by the alteration of the linear dispersion relation by the presence of sloped topography, and the extent to which a Rhines scale can explain the separation of such jets. This work is of relevance to the many regions of the oceans where strong non-zonal jets are present, and is a significant step towards understanding the influence of topography on the dynamical properties of jets.

  20. Evaluating Marie Byrd Land stability using an improved basal topography

    NASA Astrophysics Data System (ADS)

    Holschuh, N.; Pollard, D.; Alley, R. B.; Anandakrishnan, S.

    2014-12-01

    Prior understanding of the ice-sheet setting in Marie Byrd Land (MBL) was derived primarily from geologic and geochemical studies of the current nunataks, with very few geophysical surveys imaging the ice covered regions. The geologic context suggested that the ice rests on a broad regional high, in contrast to the deep basins and trenches that characterize the majority of West Antarctica. This assumed topography would favor long-term stability for the West Antarctic Ice Sheet (WAIS) in MBL. Airborne geophysical data collected in 2009 reveal a much deeper bed than previously estimated, including a significant trough underlying DeVicq Glacier and evidence for extensive glacial erosion. Using these data, we produce a new map of subglacial topography, with which we model the sensitivity of WAIS to a warming ocean using the ice-sheet model of Pollard and DeConto (2012b). We compare the results to estimates of ice loss during WAIS collapse using the previously defined subglacial topography, to determine the impact of the newly discovered subglacial features. Our results indicate that the topographic changes are not sufficient to destabilize the northern margin of MBL currently feeding the Getz Ice Shelf; the majority of ice loss occurs from flow toward the Siple Coast. However, despite only slight dynamic differences, using the new bed as a boundary condition results in an additional 8 cm of sea-level rise during major glacial retreat, an increase of just over 2%. Precise estimation of past and future ice retreat, as well as a complete understanding of the geologic history of the region, will require a higher resolution picture of the bed topography around the Executive Committee mountains.

  1. ATM Coastal Topography-Florida 2001: Western Panhandle

    USGS Publications Warehouse

    Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the western Florida panhandle coastline, acquired October 2-4 and 7-10, 2001. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative scanning Lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning Lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography.

  2. ATM Coastal Topography-Florida 2001: Eastern Panhandle

    USGS Publications Warehouse

    Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the eastern Florida panhandle coastline, acquired October 2, 2001. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative scanning Lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning Lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography.

  3. Moho depth and residual topography of the Antarctic continent

    NASA Astrophysics Data System (ADS)

    Baranov, Alexey; Molinari, Irene; Morelli, Andrea; Danesi, Stefania

    2013-04-01

    A new Moho depth map for the Antarctic continent has been recently assembled (ANTMoho), merging information retrieved from geophysical and geological studies selected from the literature. A large volume of old and new data have been analyzed: from active seismic prospection,including DSS profiles acquired by Soviet Union field experiments, to recent passive seismic receiver function and geological studies. ANTMoho has a reference lateral resolution of 1 degree. The oldest Archean and Proterozoic crust of East Antarctica has a thickness of 36-56 km (with an average of about 41 km). The continental crust of the Transantarctic Mountains, the Antarctic Peninsula and Wilkes Basin has a thickness of 30-40 km (with an average Moho of about 30 km). The youngest rifted continental crust of the West Antarctic Rift System has a thickness of 16-28 km (with an average Moho of about 26 km). The mean Moho depth of the whole model is 33.8 km. We compare this new model to other available for the whole continent (Bassin et al., 2000; Block et al., 2009) and study the possible geodynamic consequences calculating the residual topography -- an indicator of dynamic response to large-scale mantle flow. We adopt the semianalytical methodology implemented in the HC code (developed and maintained by Prof. T. Becker). The spatial resolution is limited by the L=127 of the input model. The Transantarctic Mountains appear not to be isostatically compensated, such as the neighboring Wilkes Subglacial Basin. East Antarctica on a large scale does not show significant uncompensated topography. There are however some smaller-scale residual topography features, that correlate with sub-glacial topography and that may indicate some limitation in resolution or laterally-variable crustal density. Better knowledge of crustal structure is therefore an important tool for better understanding of the complex dynamic processes acting at a regional scale.

  4. ATM Coastal Topography-Texas, 2001: UTM Zone 15

    USGS Publications Warehouse

    Klipp, Emily S.; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Yates, Xan; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Texas coastline within UTM zone 15, from Matagorda Peninsula to Galveston Island, acquired October 12-13, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

  5. ATM Coastal Topography-Texas, 2001: UTM Zone 14

    USGS Publications Warehouse

    Klipp, Emily S.; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Yates, Xan; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Texas coastline within UTM zone 14, acquired October 12-13, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

  6. Shaded relief map of US topography from digital elevations

    USGS Publications Warehouse

    Pike, R.J.; Thelin, G.P.

    1989-01-01

    Much geologic and geophysical information that lies encoded within land surface form can be revealed by image processing large files of digitized elevations in fast machines and mapping the results. This convergence of computers, analytic software, data, and output devices has created exciting opportunities for automating the numerical and spatial study of topography. One recent result is the accompanying shaded relief map of the conterminous 48 states. -from Authors

  7. Influence of topography on tropical African vegetation coverage

    NASA Astrophysics Data System (ADS)

    Jung, Gerlinde; Prange, Matthias; Schulz, Michael

    2015-07-01

    Hominid evolution in the late Miocene has long been hypothesized to be linked to the retreat of the tropical rainforest in Africa. One cause for the climatic and vegetation change often considered was uplift of Africa, but also uplift of the Himalaya and the Tibetan Plateau was suggested to have impacted rainfall distribution over Africa. Recent proxy data suggest that in East Africa open grassland habitats were available to the common ancestors of hominins and apes long before their divergence and do not find evidence for a closed rainforest in the late Miocene. We used the coupled global general circulation model CCSM3 including an interactively coupled dynamic vegetation module to investigate the impact of topography on African hydro-climate and vegetation. We performed sensitivity experiments altering elevations of the Himalaya and the Tibetan Plateau as well as of East and Southern Africa. The simulations confirm the dominant impact of African topography for climate and vegetation development of the African tropics. Only a weak influence of prescribed Asian uplift on African climate could be detected. The model simulations show that rainforest coverage of Central Africa is strongly determined by the presence of elevated African topography. In East Africa, despite wetter conditions with lowered African topography, the conditions were not favorable enough to maintain a closed rainforest. A discussion of the results with respect to other model studies indicates a minor importance of vegetation-atmosphere or ocean-atmosphere feedbacks and a large dependence of the simulated vegetation response on the land surface/vegetation model.

  8. Electronic cigarettes: abuse liability, topography and subjective effects

    PubMed Central

    Evans, Sarah E; Hoffman, Allison C

    2014-01-01

    Objective To review the available evidence evaluating the abuse liability, topography, subjective effects, craving and withdrawal suppression associated with e-cigarette use in order to identify information gaps and provide recommendations for future research. Methods Literature searches were conducted between October 2012 and January 2014 using five electronic databases. Studies were included in this review if they were peer-reviewed scientific journal articles evaluating clinical laboratory studies, national surveys or content analyses. Results A total of 15 peer-reviewed articles regarding behavioural use and effects of e-cigarettes published between 2010 and 2014 were included in this review. Abuse liability studies are limited in their generalisability. Topography (consumption behaviour) studies found that, compared with traditional cigarettes, e-cigarette average puff duration was significantly longer, and e-cigarette use required stronger suction. Data on e-cigarette subjective effects (such as anxiety, restlessness, concentration, alertness and satisfaction) and withdrawal suppression are limited and inconsistent. In general, study data should be interpreted with caution, given limitations associated with comparisons of novel and usual products, as well as the possible effects associated with subjects’ previous experience/inexperience with e-cigarettes. Conclusions Currently, very limited information is available on abuse liability, topography and subjective effects of e-cigarettes. Opportunities to examine extended e-cigarette use in a variety of settings with experienced e-cigarette users would help to more fully assess topography as well as behavioural and subjective outcomes. In addition, assessment of ‘real-world’ use, including amount and timing of use and responses to use, would clarify behavioural profiles and potential adverse health effects. PMID:24732159

  9. Correcting for surface topography in X-ray fluorescence imaging

    PubMed Central

    Geil, E. C.; Thorne, R. E.

    2014-01-01

    Samples with non-planar surfaces present challenges for X-ray fluorescence imaging analysis. Here, approximations are derived to describe the modulation of fluorescence signals by surface angles and topography, and suggestions are made for reducing this effect. A correction procedure is developed that is effective for trace element analysis of samples having a uniform matrix, and requires only a fluorescence map from a single detector. This procedure is applied to fluorescence maps from an incised gypsum tablet. PMID:25343805

  10. Bridges of the sella turcica - anatomy and topography.

    PubMed

    Skrzat, Janusz; Mroz, Izabela; Marchewka, Justyna

    2012-01-01

    This paper presents anatomy and topography of the inconstant osseous bridges that may occur in the sella turcica region. The interclinoid bridge and the caroticoclinoid bridge can be formed in consequence of abnormal ossification of the dural folds or disturbances in development of the sphenoid bone. Their presence may be of clinical importance because of potential influence on the neurovascular structures passing in the vicinity of the clinoid processes of the sphenoid bone. PMID:24852690

  11. Anomalous topography on the continental shelf around Hudson Canyon

    USGS Publications Warehouse

    Knebel, H. J.

    1979-01-01

    Recent seismic-reflection data show that the topography on the Continental Shelf around Hudson Canyon is composed of a series of depressions having variable spacings (< 100 m to 2 km), depths (1-10 m), outlines, and bottom configurations that give the sea floor an anomalous "jagged" appearance in profile. The acoustic and sedimentary characteristics, the proximity to relict shores, and the areal distribution indicate that this rough topography is an erosional surface formed on Upper Pleistocene silty sands about 13,000 to 15,000 years ago by processes related to Hudson Canyon. The pronounced southward extension of the surface, in particular, may reflect a former increase in the longshore-current erosion capacity caused by the loss of sediments over the canyon. Modern erosion or nondeposition of sediments has prevented the ubiquitous sand sheet on the Middle Atlantic shelf from covering the surface. The "anomalous" topography may, in fact, be characteristic of areas near other submarine canyons that interrupt or have interrupted the longshore drift of sediments. ?? 1979.

  12. Laboratory studies of pyroclastic flows that interact with topography

    NASA Astrophysics Data System (ADS)

    Andrews, B.; Manga, M.

    2012-04-01

    We performed a set of scaled laboratory experiments to simulate pyroclastic density currents (PDCs) using dilute mixtures of warm talc powder in air. The experiments were designed to evaluate the effects of topography on current runout, buoyancy reversal and liftoff, and mass partitioning into buoyant plumes. The densimetric and thermal Richardson, Froude, Stokes, and settling numbers for our experiments match those of PDCs and the laboratory currents are fully turbulent, although the experiments have lower Reynolds numbers than PDCs, thus our experiments are dynamically similar to natural currents. Comparisons of currents traversing flat topography or encountering barriers shows that runout distance is not significantly reduced for currents that traverse barriers with height less than 1.5 times the current thickness, but currents do not pass taller barriers. Buoyancy reversals occur in most currents, resulting in liftoff and generation of a buoyant plume. Liftoff occurs near the maximum runout distance for currents traveling over flat topography, but is focused near or above barriers for currents that encounter barriers. Notably, plume formation above barriers can result in reversal of flow direction downstream of the obstruction as portions of the current flow back and feed the rising plume. Greater than half of the initial particle mass composing the density currents usually partitions into the buoyant plumes; that fraction is greater for currents that liftoff closer to the source, thus topographic barriers increase mass partitioning from currents into buoyant plumes.

  13. Permian karst topography in the Wichita uplift, southwestern Oklahoma

    SciTech Connect

    Donovan, R.N. Busbey, A.B. . Geology Dept.)

    1993-02-01

    The Wichita uplift in southwestern Oklahoma is one part of a record of Pennsylvania and early Permian deformation that affected the Southern Oklahoma aulacogen. As a result of a partial inversion, the Lower Paleozoic section of this aulacogen was sequentially stripped off an uplift between the Wichita uplift and the Anadarko basin, resulting in the exposure of ultrabasic rocks deep in the Cambrian igneous fill of the aulacogen. Following the late Paleozoic tectonism, the topography of the uplift was entombed beneath Permian sediments and remained essentially undisturbed until exhumation during the present erosional cycle. Modern erosion is gradually exposing this topography, permitting morphometric analysis of the Permian hill forms. Because of the variation of lithology in the uplift, it is possible to isolate the effects of weathering processes such as intense hydrolysis of the igneous rocks (producing, among other features, or topography) and limestone dissolution, in the form of a surface and subsurface karst imprint. The latter process resulted in a network of small caves that are essentially fissures eroded along tectonic fractures. These small caves can be found in all the exposed areas of limestone. They are particularly noteworthy for three reasons: in at least five examples they contain a complex fauna of Permian vertebrates (mostly fragmentary), speleothems in some examples contain hydrocarbon inclusions, derived from the underlying Anadarko basin, some of the caves yield evidence of post burial evolution in the form of clay infiltration from the surface and brine flushing from the underlying Anadarko basin.

  14. Gravity-induced stresses near topography of small slope

    SciTech Connect

    McTigue, D.F.; Mei, C.C.

    1981-10-10

    Topographic modification of gravity-induced near-surface stresses results in significant departures from a lithostatic state. A perturbation scheme provides approximate analytic solutions for plane strain of an elastic half-space with an irregularly shaped free surface of small characteristic slope. The leading order effect of the topography is equivalent to that of a distributed normal load on a plane boundary, and the correction is due to a distributed shear traction on a plane boundary. Topography can exert a strong influence on the state of stress in the upper crust. An analytical solution to a relevant class of problems in elastostatics is presented: the gravity-induced stress field in a half-space with an irregularly shaped free surface. The analysis also is extended to consider the effect of topography on the stresses due to a far-field tectonic compression or tension. Motivation for this study stems from a broad range of problems in geology and geophysics. 20 references.

  15. Surface topography estimated by inversion of satellite gravity gradiometry observations

    NASA Astrophysics Data System (ADS)

    Ramillien, Guillaume

    2015-04-01

    An integration of mass elements is presented for evaluating the six components of the 2-order gravity tensor (i.e., second derivatives of the Newtonian mass integral for the gravitational potential) created by an uneven sphere topography consisting of juxtaposed vertical prisms. The method is based on Legendre polynomial series with the originality of taking elastic compensation of the topography by the Earth's surface into account. The speed of computation of the polynomial series increases logically with the observing altitude from the source of anomaly. Such a forward modelling can be easily used for reduction of observed gravity gradient anomalies by the effects of any spherical interface of density. Moreover, an iterative least-square inversion of the observed gravity tensor values ??? is proposed to estimate a regional set of topographic heights. Several tests of recovery have been made by considering simulated gradiometry anomaly data, and for varying satellite altitudes and a priori levels of accuracy. In the case of GOCE-type gradiometry anomalies measured at an altitude of ~300 km, the search converges down to a stable and smooth topography after 20-30 iterations while the final r.m.s. error is ~100 m. The possibility of cumulating satellite information from different orbit geometries is also examined for improving the prediction.

  16. Puffing Topography and Nicotine Intake of Electronic Cigarette Users

    PubMed Central

    Behar, Rachel Z.; Hua, My; Talbot, Prue

    2015-01-01

    Background Prior electronic cigarette (EC) topography data are based on two video analyses with limited parameters. Alternate methods for measuring topography are needed to understand EC use and nicotine intake. Objectives This study evaluated EC topography with a CReSS Pocket device and quantified nicotine intake. Methods Validation tests on pressure drop, flow rate, and volume confirmed reliable performance of the CReSS Pocket device. Twenty participants used Blu Cigs and V2 Cigs for 10 minute intervals with a 10–15 minute break between brands. Brand order was reversed and repeated within 7 days Data were analyzed to determine puff duration, puff count, volume, flow rate, peak flow, and inter-puff interval. Nicotine intake was estimated from cartomizer fluid consumption and topography data. Results Nine patterns of EC use were identified. The average puff count and inter-puff interval were 32 puffs and 17.9 seconds. All participants, except one, took more than 20 puffs/10 minutes. The averages for puff duration (2.65 seconds/puff), volume/puff (51ml/puff), total puff volume (1,579 ml), EC fluid consumption (79.6 mg), flow rate (20 ml/s), and peak flow rate (27 ml/s) were determined for 10-minute sessions. All parameters except total puff count were significantly different for Blu versus V2 EC. Total volume for Blu versus V2 was four-times higher than for conventional cigarettes. Average nicotine intake for Blu and V2 across both sessions was 1.2 ± 0.5 mg and 1.4 ± 0.7 mg, respectively, which is similar to conventional smokers. Conclusions EC puffing topography was variable among participants in the study, but often similar within an individual between brands or days. Puff duration, inter-puff interval, and puff volume varied from conventional cigarette standards. Data on total puff volume and nicotine intake are consistent with compensatory usage of EC. These data can contribute to the development of a standard protocol for laboratory testing of EC products. PMID:25664463

  17. Reconstructing Pliocene coastlines, topography and bathymetry: A geodynamic perspective

    NASA Astrophysics Data System (ADS)

    Chandan, D.; Peltier, W. R.

    2014-12-01

    The middle Pliocene period (~3.3-3.0 Mya) was characterized by warm temperatures (2-3? higher) and high carbon-dioxide (~400 ppmv) concentrations which has led to its recognition as a possible analogue for the future climate. Under the auspices of the Pliocene Modeling and Intercomparison Project (PlioMIP), general circulation models (GCM's) are being employed to simulate mid-Pliocene climate to better understand the biases in these models, which are presently used to make future climate predictions. Necessary boundary conditions for these simulations — land mask, topography, surface albedo and vegetation cover are being provided by the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) project. Bathymetry, which is not part of the PRISM supplied dataset has been adjusted by raising the sea-level by an assumed constant eustatic amount. At present the PRISM land mask, topography and bathymetry reconstructions do not incorporate the gravitationally self consistent changes that would be required to account for the mass loss from the Greenland and Antarctic ice-sheets that produced the assumed rise in eustatic sea level. The effects of dynamic topography induced corrections, due to the action of the mantle convection process, have also been neglected.The influence of these corrections on the predictions of Pliocene climate using modern GCM's remains unexplored. The continuing failure of these models to simulate proxy inferred levels of warming in high-latitude [Dowsett et al., 2013, Sci. Rep.] regions where the magnitude of the required corrections are expected to be largest make it especially important that their impact be assessed. Here, we present the results from a preliminary of the required modifications to the boundary condition data sets.We compute the gravitationally self consistent corrections using the viscoelastic theory of global, glacial isostatic adjustment and relative sea level history for a spherically symmetric Earth model. Dynamic topography related changes are computed using a 3D convection model initialized using seismic tomography. Together, this creates an updated picture of the mid-Pliocene shoreline, topography and bathymetry that can be employed as boundary conditions for future Pliocene climate modeling.

  18. Global snowline and mountain topography: a contrasted view

    NASA Astrophysics Data System (ADS)

    Champagnac, Jean-Daniel; Herman, Frédéric; Valla, Pierre

    2013-04-01

    The examination of the relationship between Earth's topography and present and past climate (i.e., long-term elevation of glaciers Equilibrium Line Altitude) reveals that the elevation of mountain ranges may be limited or controlled by glaciations (e.g. Porter, 1989). This is of prime importance, because glacial condition would lead to a limit the mountain development, hence the accumulation of gravitational energy and prevent the development of further glacial conditions as well as setting the erosion in (peri)glacial environments. In this study, we examine the relationships between topography and the global Equilibrium Line Altitude of alpine glaciers around the world (~ long term snowline, i.e. the altitude where the ice mass balance is null). This analysis reinforce a global study previously published (Champagnac et al., 2012), and provide a much finer view of the climate-topography-tectonics relationships. Specifically, two main observations can be drawn: 1) The distance between the (averaged and maximum) topography, and the ELA decreases pole ward the poles, and even become reversed (mean elevation above to ELA) at high latitude. Correlatively, the elevation of very large portion of land at mid-latitude cannot be related to glaciations, simply because it was never glaciated (large distance between topography and long-term mean ELA). The maximum distance between the ELA and the topography is greater close to the equator and decreases poleward. In absence of glacial and periglacial erosion, this trend cannot have its origin in glacial and periglacial processes. Moreover, the ELA elevation shows a significant (1000~1500m) depression in the intertropical zone. This depression of the ELA is not reflected at all in the topography 2) The distribution of relief on Earth, if normalized by the mean elevation of mountain ranges (as a proxy for available space to create relief, see Champagnac et al., 2012 for details) shows a latitudinal band of greater relief between ~40 and ~60° (or between ELA of ~500m to ~2500m a.s.l.). This mid-latitude relatively greater relief challenges the straightforward relationship between glaciations, erosion and topography. Oppositely, it suggests that glacier may be more efficient agent in temperate area, with an important amplitude between glacial and interglacial climate. This is consistent with the view of a very variable glacier erodibility that can erode and protect the landscape, as well as with studies documenting a bimodal location of the preferred glacial erosion, at relatively high elevation (around the long-term ELA), and at much lower elevation (close to the glacial maximum lower reaches), thanks to efficient water lubrication of the glacier bases that greatly enhance the sliding velocity (Herman et al., 2011). These findings show that the relation between the mountain topography and the long term snowline is not as straightforward as previously proposed (e.g. Egholm et al., 2009) . Beside the role of tectonic forcing highlighted by several authors (e.g. Pedersen et al., 2010;Spotila and Berger, 2010),, the importance of the glacial erosion appears to be crucial at mid latitude, but more complex at both high and low latitude. Moreover, the relief at mid latitude appears to be higher, hence suggesting a positive correlation between relief and topographic control of glacier on the landscape Champagnac, J.-D., Molnar, P., Sue, C., and Herman, F.: Tectonics, Climate, and Mountain Topography, Journal of Geophysical Research B: Solid Earth, 117, doi:10.1029/2011JB008348, 2012. Egholm, D. L., Nielsen, S. B., Pedersen, V. K., and Lesemann, J. E.: Glacial effects limiting mountain height, Nature, 460, 884-888, 2009. Herman, F., Beaud, F., Champagnac, J.-D., Lemieux, J.-M., and Sternai, P.: Glacial hydrology and erosion patterns: A mechanism for carving glacial valleys, Earth and Planetary Science Letters, 310, 498-508, 2011. Pedersen, V. K., Egholm, D. L., and Nielsen, S. B.: Alpine glacial topography and the rate of rock column uplift: a global perspective, Geomorphology, 122, 129-139, 10.1

  19. Open questions in surface topography measurement: a roadmap

    NASA Astrophysics Data System (ADS)

    Leach, Richard; Evans, Christopher; He, Liangyu; Davies, Angela; Duparré, Angela; Henning, Andrew; Jones, Christopher W.; O'Connor, Daniel

    2015-03-01

    Control of surface topography has always been of vital importance for manufacturing and many other engineering and scientific disciplines. However, despite over one hundred years of quantitative surface topography measurement, there are still many open questions. At the top of the list of questions is ‘Are we getting the right answer?’ This begs the obvious question ‘How would we know?’ There are many other questions relating to applications, the appropriateness of a technique for a given scenario, or the relationship between a particular analysis and the function of the surface. In this first ‘open questions’ article we have gathered together some experts in surface topography measurement and asked them to address timely, unresolved questions about the subject. We hope that their responses will go some way to answer these questions, address areas where further research is required, and look at the future of the subject. The first section ‘Spatial content characterization for precision surfaces’ addresses the need to characterise the spatial content of precision surfaces. Whilst we have been manufacturing optics for centuries, there still isn’t a consensus on how to specify the surface for manufacture. The most common three methods for spatial characterisation are reviewed and compared, and the need for further work on quantifying measurement uncertainties is highlighted. The article is focussed on optical surfaces, but the ideas are more pervasive. Different communities refer to ‘figure, mid-spatial frequencies, and finish’ and ‘form, waviness, and roughness’, but the mathematics are identical. The second section ‘Light scattering methods’ is focussed on light scattering techniques; an important topic with in-line metrology becoming essential in many manufacturing scenarios. The potential of scattering methods has long been recognized; in the ‘smooth surface limit’ functionally significant relationships can be derived from first principles for statistically stationary, random surfaces. For rougher surfaces, correlations can be found experimentally for specific manufacturing processes. Improvements in computational methods encourage us to revisit light scattering as a powerful and versatile tool to investigate surface and thin film topographies, potentially providing information on both topography and defects over large areas at high speed. Future scattering techniques will be applied for complex film systems and for sub-surface damage measurement, but more research is required to quantify and standardise such measurements. A fundamental limitation of all topography measurement systems is their finite spatial bandwidth, which limits the slopes that they can detect. The third section ‘Optical measurements of surfaces containing high slope angles’ discusses this limitation and potential methods to overcome it. In some cases, a rough surface can allow measurement of slopes outside the classical optics limit, but more research is needed to fully understand this process. The last section ‘What are the challenges for high dynamic range surface measurement?’ presents the challenge facing metrologists by the use of surfaces that need measurement systems with very high spatial and temporal bandwidths, for example, those found in roll-to-roll manufacturing. High resolution, large areas and fast measurement times are needed, and these needs are unlikely to be fulfilled by developing a single all-purpose instrument. A toolbox of techniques needs to be developed which can be applied for any specific manufacturing scenario. The functional significance of surface topography has been known for centuries. Mirrors are smooth. Sliding behaviour depends on roughness. We have been measuring surfaces for centuries, but we still face many challenges. New manufacturing paradigms suggest that we need to make rapid measurements online that relate to the functional performance of the surface. This first ‘open questions’ collection addresses a subset of the challenges facing the surface metrology commun

  20. Geophysics of Titan from gravity, topography and spin state

    NASA Astrophysics Data System (ADS)

    Nimmo, F.; Bills, B. G.

    2011-12-01

    For the terrestrial planets, combined analyses of gravity and topography have greatly improved our understanding of these bodies' interiors [1]. The spin state and orientation of a planetary body can also be diagnostic of its internal structure [2]. Recently acquired topography [3], gravity [4] and spin pole constraints [5] now permit these kinds of geophysical analyses at Titan. Titan's degree-two gravity coefficients, but not those of its topography, are in the 10/3 ratio expected for a hydrostatic body. One explanation for this discrepancy is the existence of a floating isostatic ice shell whose thickness varies spatially due to tidal dissipation [6]. Shell thickness variations can result in slow non-synchronous rotation [7]. Furthermore, such variations will affect the gravity, an effect that should be taken into account when using gravity to calculate Titan's moment of inertia [4]. The relationship between the degree-three gravity and topography can be used to place constraints on the thickness and rigidity of the ice shell. Based on the inferred heat fluxes of [6], Titan's ice shell is unlikely to be less than 90% compensated at degree three. The measured degree-three gravity [4] and topography [3] coefficients show a strong correlation (r=0.84). For a completely compensated ice shell, the implied shell thickness is about 350 km, while if the shell is 90% compensated the thickness is 250 km. These shell thickness estimates significantly exceed those based on theoretical models [8,9] and surface topography [6]. One possible explanation for this discrepancy is that there are other sources of degree-three gravity (e.g. bumps on the presumed silicate core) that do not contribute significantly to the surface topography. Further gravity observations will help to resolve this issue. If a satellite's spin and orbit poles remain coplanar as the latter precesses around the invariable pole, the satellite is said to occupy a damped Cassini state and the obliquity (angle between spin and orbit pole) is diagnostic of its moment of inertia [10]. Titan's spin pole is very nearly coplanar with the orbit and invariable poles, suggesting occupation of a Cassini state. Its obliquity of 0.32 degrees [5] corresponds to a normalized moment of inertia of 0.45, much larger than the value of 0.34 derived from gravity [4]. This discrepancy is probably due mostly to decoupling of the ice shell from the interior by an ocean, though excitation of the obliquity by the atmosphere [11] or ocean may also play a role. [1] Wieczorek, M.A., Treatise Geophys. 10, 165-206, 2007. [2] Williams, J.G. et al., JGR 106, 27933-27968, 2001. [3] Zebker, H.A. et al., Science 324, 921-923, 2009. [4] Iess, L. et al., Science 327, 1367-1369, 2010. [5] Stiles, B.W. et al., Astron. J. 135, 1669-1680, 2008. [6] Nimmo, F., B.G. Bills, Icarus 208, 896-904, 2010. [7] Ojakangas, G.W., D.J. Stevenson, Icarus 81, 220-41, 1989. [8] Tobie, G. et al., Nature 440, 61-64, 2006. [9] Sohl, F. et al., JGR 108, 5130, 2003. [10] Bills, B.G., F. Nimmo, Icarus 214, 351-355, 2011. [11] Tokano, T. et al., JGR 116, E05002, 2011.

  1. Effect of mesoscale topography over the Tibetan Plateau on summer precipitation in China: A regional model study

    E-print Network

    Wang, Yuqing

    Effect of mesoscale topography over the Tibetan Plateau on summer precipitation in China 2008; accepted 27 August 2008; published 8 October 2008. [1] The effect of mesoscale topography over and topography. In the sensitivity simulation, the mesoscale feature in topography over the TP was smoothed out

  2. Wide angle cornea-sclera (ocular) topography Stanley A. Klein, John Corzine, School of Optometry, University of California, Berkeley

    E-print Network

    Klein, Stanley

    Wide angle cornea-sclera (ocular) topography Stanley A. Klein, John Corzine, School of Optometry is noisier, it is the only topographer available able to measure scleral topography that is critically OCULAR TOPOGRAPHY During the period from 1992 to 1999 corneal topography became a major focus for cornea

  3. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 43, NO. 8, AUGUST 2005 1707 Validation of the Shuttle Radar Topography

    E-print Network

    Sarabandi, Kamal

    of the Shuttle Radar Topography Mission Height Data Charles G. Brown, Jr., Member, IEEE, Kamal Sarabandi, Fellow, IEEE, and Leland E. Pierce, Senior Member, IEEE Abstract--The Shuttle Radar Topography Mission (SRTM Radar Topography Mission, validation. I. INTRODUCTION THE Shuttle Radar Topography Mission (SRTM

  4. P300 Topography Differs in Schizophrenia and Manic Dean F. Salisbury, Martha E. Shenton, and Robert W. McCarley

    E-print Network

    P300 Topography Differs in Schizophrenia and Manic Psychosis Dean F. Salisbury, Martha E. Shenton demonstrated in schizophrenia. P300 amplitude and topography in psychotic affective disorder, a crucial topography alone, differences in topography imply different generator configurations. Based on previous

  5. Crater topography on Titan: Implications for landscape evolution

    NASA Astrophysics Data System (ADS)

    Neish, C.; Kirk, R.; Lorenz, R.; Bray, V.; Schenk, P.; Stiles, B.; Turtle, E.; Cassini Radar Team

    2012-04-01

    Unique among the icy satellites, Titan’s surface shows evidence for extensive modification by fluvial and aeolian erosion, which act to change the topography of its surface over time. Quantifying the extent of this landscape evolution is difficult, since the original, ‘non-eroded’ surface topography is generally unknown. However, fresh craters on icy satellites have a well-known shape and morphology, which has been determined from extensive studies on the airless worlds of the outer solar system (Schenk et al., 2004). By comparing the topography of craters on Titan to similarly sized, pristine analogues on airless bodies, we can obtain one of the few direct measures of the amount of erosion that has occurred on Titan. Cassini RADAR has imaged >30% of the surface of Titan, and more than 60 potential craters have been identified in this data set (Wood et al., 2010; Neish and Lorenz, 2012). Topographic information for these craters can be obtained from a technique known as ‘SARTopo’, which estimates surface heights by comparing the calibration of overlapping synthetic aperture radar (SAR) beams (Stiles et al., 2009). We present topography data for several craters on Titan, and compare the data to similarly sized craters on Ganymede, for which topography has been extracted from stereo-derived digital elevation models (Bray et al., 2012). We find that the depths of craters on Titan are generally within the range of depths observed on Ganymede, but several hundreds of meters shallower than the average (Fig. 1). A statistical comparison between the two data sets suggests that it is extremely unlikely that Titan’s craters were selected from the depth distribution of fresh craters on Ganymede, and that is it much more probable that the relative depths of Titan are uniformly distributed between ‘fresh’ and ‘completely infilled’. This is consistent with an infilling process that varies linearly with time, such as aeolian infilling. Figure 1: Depth of craters on Titan (gray diamonds) compared to similarly sized, fresh craters on Ganymede (central peaks, +; central pits, *) and a handful of relaxed craters (black squares) from Bray et al. (2012). References: Bray, V., et al.: "Ganymede crater dimensions - implications for central peak and central pit formation and development". Icarus, Vol. 217, pp. 115-129, 2012. Neish, C.D., Lorenz, R.D.: "Titan’s global crater population: A new assessment". Planetary and Space Science, Vol. 60, pp. 26-33, 2012. Schenk, P.M., et al.: "Ages and interiors: the cratering record of the Galilean satellites". In: Bagenal, F., McKinnon, W.B. (Eds.), Jupiter: The Planet, Satellites, and Magnetosphere, Cambridge University Press, Cambridge, UK, pp. 427-456, 2004. Stiles, B.W., et al.: "Determining Titan surface topography from Cassini SAR data". Icarus, Vol. 202, pp. 584-598, 2009. Wood, C.A., et al.: "Impact craters on Titan". Icarus, Vol. 206, pp. 334-344, 2010.

  6. Influence of subduction history on South American topography

    NASA Astrophysics Data System (ADS)

    Flament, Nicolas; Gurnis, Michael; Müller, R. Dietmar; Bower, Dan J.; Husson, Laurent

    2015-11-01

    The Cenozoic evolution of South American topography is marked by episodes of large-scale uplift and subsidence not readily explained by lithospheric deformation. The drying up of the inland Pebas system, the drainage reversal of the Amazon river, the uplift of the Sierras Pampeanas and the uplift of Patagonia have all been linked to the evolution of mantle flow since the Miocene in separate studies. Here we investigate the evolution of long-wavelength South American topography as a function of subduction history in a time-dependent global geodynamic model. This model is shown to be consistent with these inferred changes, as well as with the migration of the Chaco foreland basin depocentre, that we partly attribute to the inboard migration of subduction resulting from Andean mountain building. We suggest that the history of subduction along South America has had an important influence on the evolution of the topography of the continent because time-dependent mantle flow models are consistent with the history of vertical motions as constrained by the geological record at four distant areas over a whole continent. Testing alternative subduction scenarios reveals flat slab segments are necessary to reconcile inferred Miocene shorelines with a simple model paleogeography. As recently suggested, we find that the flattening of a subduction zone results in dynamic uplift between the leading edge of the flat slab segment and the trench, and in a wave of dynamic subsidence associated with the inboard migration of the leading edge of flat subduction. For example, the flattening of the Peruvian subduction contributed to the demise of Pebas shallow-water sedimentation, while continental-scale tilting also contributed to the drainage reversal of the Amazon River. The best correlation to P-wave tomography models for the Peruvian flat slab segment is obtained for a case when the asthenosphere, here considered to be 150 km thick and 10 times less viscous than the upper mantle, is restricted to the oceanic domain.

  7. Topography and biological noise determine acoustic detectability on coral reefs

    NASA Astrophysics Data System (ADS)

    Cagua, E. F.; Berumen, M. L.; Tyler, E. H. M.

    2013-12-01

    Acoustic telemetry is an increasingly common tool for studying the movement patterns, behavior and site fidelity of marine organisms, but to accurately interpret acoustic data, the variability, periodicity and range of detectability between acoustic tags and receivers must be understood. The relative and interactive effects of topography with biological and environmental noise have not been quantified on coral reefs. We conduct two long-term range tests (1- and 4-month duration) on two different reef types in the central Red Sea to determine the relative effect of distance, depth, topography, time of day, wind, lunar phase, sea surface temperature and thermocline on detection probability. Detectability, as expected, declines with increasing distance between tags and receivers, and we find average detection ranges of 530 and 120 m, using V16 and V13 tags, respectively, but the topography of the reef can significantly modify this relationship, reducing the range by ~70 %, even when tags and receivers are in line-of-sight. Analyses that assume a relationship between distance and detections must therefore be used with care. Nighttime detection range was consistently reduced in both locations, and detections varied by lunar phase in the 4-month test, suggesting a strong influence of biological noise (reducing detection probability up to 30 %), notably more influential than other environmental noises, including wind-driven noise, which is normally considered important in open-water environments. Analysis of detections should be corrected in consideration of the diel patterns we find, and range tests or sentinel tags should be used for more than 1 month to quantify potential changes due to lunar phase. Some studies assume that the most usual factor limiting detection range is weather-related noise; this cannot be extrapolated to coral reefs.

  8. Development of topography in 3-D continental-collision models

    NASA Astrophysics Data System (ADS)

    Pusok, A. E.; Kaus, Boris J. P.

    2015-05-01

    Understanding the formation and evolution of high mountain belts, such as the Himalayas and the adjacent Tibetan Plateau, has been the focus of many tectonic and numerical models. Here we employ 3-D numerical simulations to investigate the role that subduction, collision, and indentation play on lithosphere dynamics at convergent margins, and to analyze the conditions under which large topographic plateaus can form in an integrated lithospheric and upper mantle-scale model. Distinct dynamics are obtained for the oceanic subduction side (trench retreat, slab rollback) and the continental-collision side (trench advance, slab detachment, topographic uplift, lateral extrusion). We show that slab pull alone is insufficient to generate high topography in the upper plate, and that external forcing and the presence of strong blocks such as the Tarim Basin are necessary to create and shape anomalously high topographic fronts and plateaus. Moreover, scaling is used to predict four different modes of surface expression in continental-collision models: (I) low-amplitude homogeneous shortening, (II) high-amplitude homogeneous shortening, (III) Alpine-type topography with topographic front and low plateau, and (IV) Tibet-Himalaya-type topography with topographic front and high plateau. Results of semianalytical models suggest that the Argand number governs the formation of high topographic fronts, while the amplitude of plateaus is controlled by the initial buoyancy ratio of the upper plate. Applying these results to natural examples, we show that the Alps belong to regime (III), the Himalaya-Tibet to regime (IV), whereas the Andes-Altiplano fall at the boundary between regimes (III) and (IV).

  9. Gravity Field, Topography, and Interior Structure of Amalthea

    NASA Astrophysics Data System (ADS)

    Anderson, J. D.; Anabtawi, A.; Jacobson, R. A.; Johnson, T. V.; Lau, E. L.; Moore, W. B.; Schubert, G.; Taylor, A. H.; Thomas, P. C.; Weinwurm, G.

    2002-12-01

    A close Galileo flyby of Jupiter's inner moon Amalthea (JV) occurred on 5 November 2002. The final aimpoint was selected by the Galileo Radio Science Team on 5 July 2002. The closest approach distance for the selected aimpoint was 221 km from the center of mass, the latitude was - 45.23 Deg and the west longitude was 266.41 Deg (IAU/IAG/COSPAR cartographic coordinate system). In order to achieve an acceptable impact probability (0.15%), and yet fly close to Amalthea, the trajectory was selected from a class of trajectories running parallel to Amalthea's long axis. The Deep Space Network (DSN) had the capability to generate continuous coherent radio Doppler data during the flyby. Such data can be inverted to obtain information on Amalthea's gravity field. Amalthea is irregular and neither a triaxial ellipsoid nor an equilibrium body. It has a volume of about 2.4 x 106 km3, and its best-fit ellipsoid has dimensions 131x73x67 km. Its mass can be determined from the 2002 flyby, and in combination with the volume, a density can be obtained accurate to about 5%, where the error is dominated by the volume uncertainty. Similarly, gravity coefficients (Cnm Snm) can be detected up to fourth degree and order, and the second degree field (quadrupole) can be measured. Topography data are available from Voyager imaging and from images taken with Galileo's solid state imaging system at various times between February and June 1997. By combining the gravity and topography data, new information can be obtained on Amalthea's interior. For example if the gravity coefficients agree with those calculated from the topography, assuming constant density, we can conclude that Amalthea is homogeneous. On the other hand, if the gravity coefficients are smaller than predicted from topography, we can conclude that there is a concentration of mass toward Amalthea's center. We are presenting preliminary pre-publication results at the Fall meeting. This work was sponsored by the Galileo Project and was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. G.S., P.C.T., and W.B.M. acknowledge support by grants from NASA under the Planetary Geology and Geophysics program. G.W. is a visiting PhD student at JPL, May 2002 - May 2003, and acknowledges support from the Austrian Ministry for Technology and a Zonta - Amelia Earhart fellowship.

  10. Dynamic wetting and spreading and the role of topography.

    PubMed

    McHale, Glen; Newton, Michael I; Shirtcliffe, Neil J

    2009-11-18

    The spreading of a droplet of a liquid on a smooth solid surface is often described by the Hoffman-de Gennes law, which relates the edge speed, v(e), to the dynamic and equilibrium contact angles ? and ?(e) through [Formula: see text]. When the liquid wets the surface completely and the equilibrium contact angle vanishes, the edge speed is proportional to the cube of the dynamic contact angle. When the droplets are non-volatile this law gives rise to simple power laws with time for the contact angle and other parameters in both the capillary and gravity dominated regimes. On a textured surface, the equilibrium state of a droplet is strongly modified due to the amplification of the surface chemistry induced tendencies by the topography. The most common example is the conversion of hydrophobicity into superhydrophobicity. However, when the surface chemistry favors partial wetting, topography can result in a droplet spreading completely. A further, frequently overlooked consequence of topography is that the rate at which an out-of-equilibrium droplet spreads should also be modified. In this report, we review ideas related to the idea of topography induced wetting and consider how this may relate to dynamic wetting and the rate of droplet spreading. We consider the effect of the Wenzel and Cassie-Baxter equations on the driving forces and discuss how these may modify power laws for spreading. We relate the ideas to both the hydrodynamic viscous dissipation model and the molecular-kinetic theory of spreading. This suggests roughness and solid surface fraction modified Hoffman-de Gennes laws relating the edge speed to the dynamic and equilibrium contact angle. We also consider the spreading of small droplets and stripes of non-volatile liquids in the capillary regime and large droplets in the gravity regime. In the case of small non-volatile droplets spreading completely, a roughness modified Tanner's law giving the dependence of dynamic contact angle on time is presented. We review existing data for the spreading of small droplets of polydimethylsiloxane oil on surfaces decorated with micro-posts. On these surfaces, the initial droplet spreads with an approximately constant volume and the edge speed-dynamic contact angle relationship follows a power law [Formula: see text]. As the surface texture becomes stronger the exponent goes from p = 3 towards p = 1 in agreement with a Wenzel roughness driven spreading and a roughness modified Hoffman-de Gennes power law. Finally, we suggest that when a droplet spreads to a final partial wetting state on a rough surface, it approaches its Wenzel equilibrium contact angle in an exponential manner with a time constant dependent on roughness. PMID:21715886

  11. X-ray topography study of complex silicon microcircuits

    NASA Technical Reports Server (NTRS)

    Parker, D. L.

    1981-01-01

    The correlation between the yield of silicon microcircuits wafers versus defects observed in X-ray topographs produced by a high speed curved wafer X-ray topographic camera was investigated. Most of the topographs were made after final wafer probe. Results indicated that most high volume silicon wafer processing does not need X-ray topography as a routine process control. It is further indicated that in changing any existing process or developing a new process the technique can be of significant benefit.

  12. EAARL Topography - Natchez Trace Parkway 2007: First Surface

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Segura, Martha; Yates, Xan

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Natchez Trace Parkway in Mississippi, acquired on September 14, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  13. EAARL Topography - Jean Lafitte National Historical Park and Preserve 2006

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Segura, Martha; Yates, Xan

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) and bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Jean Lafitte National Historical Park and Preserve in Louisiana, acquired on September 22, 2006. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  14. EAARL Coastal Topography - Fire Island National Seashore 2007

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) and bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of Fire Island National Seashore in New York, acquired on April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for pre-survey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  15. The world next door - Results in landscape topography

    E-print Network

    Ulf H. Danielsson; Niklas Johansson; Magdalena Larfors

    2006-12-20

    Recently, it has become clear that neighboring multiple vacua might have interesting consequences for the physics of the early universe. In this paper we investigate the topography of the string landscape corresponding to complex structure moduli of flux compactified type IIB string theory. We find that series of continuously connected vacua are common. The properties of these series are described, and we relate the existence of infinite series of minima to certain unresolved mathematical problems in group theory. Numerical studies of the mirror quintic serve as illustrating examples.

  16. EAARL Topography - Vicksburg National Military Park 2008: Bare Earth

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Segura, Martha; Yates, Xan

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Vicksburg National Military Park in Mississippi, acquired on March 6, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  17. EAARL Submerged Topography - U.S. Virgin Islands 2003

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived submerged topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), South Florida-Caribbean Network, Miami, FL; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate bathymetric datasets of a portion of the U.S. Virgin Islands, acquired on April 21, 23, and 30, May 2, and June 14 and 17, 2003. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  18. EAARL Coastal Topography - Northern Gulf of Mexico, 2007: Bare Earth

    USGS Publications Warehouse

    Smith, Kathryn E.L.; Nayegandhi, Amar; Wright, C. Wayne; Bonisteel, Jamie M.; Brock, John C.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. The purpose of this project is to provide highly detailed and accurate datasets of select barrier islands and peninsular regions of Louisiana, Mississippi, Alabama, and Florida, acquired on June 27-30, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  19. EAARL Coastal Topography-Chandeleur Islands, Louisiana, 2010: Bare Earth

    USGS Publications Warehouse

    Nayegandhi, Amar; Bonisteel-Cormier, Jamie M.; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Nagle, David B.; Vivekanandan, Saisudha; Yates, Xan; Klipp, Emily S.

    2010-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived bare-earth (BE) and submerged topography datasets were produced collaboratively by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Chandeleur Islands, acquired March 3, 2010. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations. For more information about similar projects, please visit the Decision Support for Coastal Science and Management website.

  20. EAARL Topography - George Washington Birthplace National Monument 2008

    USGS Publications Warehouse

    Brock, John C.; Nayegandhi, Amar; Wright, C. Wayne; Stevens, Sara; Yates, Xan

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) and first surface (FS) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the George Washington Birthplace National Monument in Virginia, acquired on March 26, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  1. EAARL Coastal Topography - Northeast Barrier Islands 2007: First Surface

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Yates, Xan; Bonisteel, Jamie M.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the northeast coastal barrier islands in New York and New Jersey, acquired April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  2. EAARL Coastal Topography - Northeast Barrier Islands 2007: Bare Earth

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the northeast coastal barrier islands in New York and New Jersey, acquired April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  3. EAARL Coastal Topography--Cape Canaveral, Florida, 2009: First Surface

    USGS Publications Warehouse

    Bonisteel-Cormier, J.M.; Nayegandhi, Amar; Plant, Nathaniel; Wright, C.W.; Nagle, D.B.; Serafin, K.S.; Klipp, E.S.

    2011-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography datasets were produced collaboratively by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Kennedy Space Center, FL. This project provides highly detailed and accurate datasets of a portion of the eastern Florida coastline beachface, acquired on May 28, 2009. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine aircraft, but the instrument was deployed on a Pilatus PC-6. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the "bare earth" under vegetation from a point cloud of last return elevations.

  4. Evolution of topography on comets. II - Icy craters and trenches

    NASA Technical Reports Server (NTRS)

    Colwell, Joshua E.; Jakosky, Bruce M.; Sandor, Bradford J.; Stern, S. Alan

    1990-01-01

    The determination of the effects of topography on the sublimation rates of comets and other icy bodies is presently approached via a model of ice heating and sublimation from topographical features. The energy balance equation is solved for cylindrical trenches and spherical craters; the model encompasses shadowing, solar heating, the trapping of thermal radiation and sublimed gas molecules, and reflection of sunlight within the cavity. Generally, an enhancement is found in the net sublimation rate for trenches and craters farther from the sun than some critical distance which depends on the albedo.

  5. Applications of laser ranging to ocean, ice, and land topography

    NASA Technical Reports Server (NTRS)

    Degnan, John J.

    1991-01-01

    The current status and some future applications of satellite laser ranging (SLR) are briefly reviewed. The demonstrated subcentimeter precision of ground-based SLR systems is attracting new users, particularly, in the area of high-resolution ocean, ice, and land topography. Future airborne or spaceborne SLR system will not only provide topographic data with a horizontal and vertical resolution never achieved previously, but, in addition, ground-based SLR systems, via precise tracking of spaceborne microwave and laser altimeters, will permit the expression of the topographic surface in a common geocentric reference frame.

  6. Topography of the Moon from the Clementine Lidar

    NASA Technical Reports Server (NTRS)

    Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Lemoine, Frank G.

    1997-01-01

    Range measurements from the lidar instrument carried aboard the Clementine spacecraft have been used to produce an accurate global topographic model of the Moon. This paper discusses the function of the lidar; the acquisition, processing, and filtering of observations to produce a global topographic model; and the determination of parameters that define the fundamental shape of the Moon. Our topographic model: a 72nd degree and order spherical harmonic expansion of lunar radii, is designated Goddard Lunar Topography Model 2 (GLTM 2). This topographic field has an absolute vertical accuracy of approximately 100 m and a spatial resolution of 2.5 deg. The field shows that the Moon can be described as a sphere with maximum positive and negative deviations of approx. 8 km, both occurring on the farside, in the areas of the Korolev and South Pole-Aitken (S.P.-Aitken) basins. The amplitude spectrum of the topography shows more power at longer wavelengths as compared to previous models, owing to more complete sampling of the surface, particularly the farside. A comparison of elevations derived from the Clementine lidar to control point elevations from the Apollo laser altimeters indicates that measured relative topographic heights generally agree to within approx. 200 in over the maria. While the major axis of the lunar gravity field is aligned in the Earth-Moon direction, the major axis of topography is displaced from this line by approximately 10 deg to the cast and intersects the farside 24 deg north of the equator. The magnitude of impact basin topography is greater than the lunar flattening (approx. 2 km) and equatorial ellipticity (approx. 800 m), which imposes a significant challenge to interpreting the lunar figure. The floors of mare basins are shown to lie close to an equipotential surface, while the floors of unflooded large basins, except for S.P.-Aitken, lie above this equipotential. The radii of basin floors are thus consistent with a hydrostatic mechanism for the absence of significant farside maria except for S.P.-Aitken, whose depth and lack of mare require significant internal compositional and/or thermal heterogeneity. A macroscale surface roughness map shows that roughness at length scales of 10(exp 1) - 10(exp 2) km correlates with elevation and surface age.

  7. EAARL Coastal Topography-Pearl River Delta 2008: Bare Earth

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Miner, Michael D.; Yates, Xan; Bonisteel, Jamie M.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the University of New Orleans (UNO), Pontchartrain Institute for Environmental Sciences (PIES), New Orleans, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Pearl River Delta in Louisiana and Mississippi, acquired March 9-11, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  8. EAARL Coastal Topography-Pearl River Delta 2008: First Surface

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Miner, Michael D.; Michael, D.; Yates, Xan; Bonisteel, Jamie M.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the University of New Orleans (UNO), Pontchartrain Institute for Environmental Sciences (PIES), New Orleans, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Pearl River Delta in Louisiana and Mississippi, acquired March 9-11, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

  9. Mars ultraviolet reflectance compared with imaging, topography and geology

    NASA Astrophysics Data System (ADS)

    Simmons, K. E.; Mankoff, K. D.; Hendrix, A. R.; Barth, C. A.

    2003-04-01

    We compare ultraviolet reflectance spectra from the Mariner Mars 1971 (MM71) Ultraviolet Spectrometer (UVS) with imaging data from the Viking Mars Digital Image Model (MDIM), with surface topography from the Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA), and with geology from the USGS Survey Atlas of Mars digital maps. We use a new web-accessible database of MM71 UVS Reflectances and two software tools: 1) a surface and atmosphere database visualization tool called Albatross and 2) a web-based Mars data comparison tool called MDC. See http://lasp.colorado.edu/software_tools/. We present several examples, including the northern polar region and Lyot Crater.

  10. Pre-glacial topography of the European Alps

    NASA Astrophysics Data System (ADS)

    Sternai, P.; Herman, F.; Champagnac, J.-D.; Fox, M.; Salcher, B.; Willett, S. D.

    2012-04-01

    We present a reconstruction of the Alpine topography prior to Quaternary glaciation, based on the assumption that the pre-glacial topography of the Alps was a fluvial landscape in equilibrium with tectonic and isostatic rock uplift. Amongst the models that have been proposed, the stream-power law has been profitably used for modeling the dynamics of fluvial bedrock channel incision: dz-= U - KAmSn dt (1) where dz/dt (m a-1) is the time rate of change of channel elevation, U(m a-1) is rock-uplift rate, A(m) is upstream drainage area, S is local channel gradient, K is a dimensionless coefficient of erosion and m and n are positive constants related to basin hydrology and erosion process. Under steady-state conditions (dz/dt = 0), equation (1) can be solved to yield an expression for equilibrium channel gradient: 1 ( U-)n - (m) S = K A n (2) where the ratios U/K and m/n are generally referred to as the steepness and concavity index, respectively. Particular focus is put on the spatial variability of the steepness index over the Alpine mountain belt. Assuming a constant concavity index, the pre-glacial topography of the Alps is obtained through an inversion technique that resolves local slopes (as described in eq. 2) by minimizing the misfit between the elevations of the actual and modeled channel heads. Comparing the present-day and reconstructed pre-glacial topography, we infer patterns and magnitudes of exhumation and rock uplift produced by Quaternary glaciation in the Alps. We find a correspondence between rock type and pre-glacial channel steepness which may indicate that rock erodibility has a significant importance in determining the pre-glacial fluvial network elevation. Our results also provide insight into patterns of glacial erosion and associated isostatic adjustment, and provide estimates of the increase of valley-scale topographic relief and decrease of mean elevation that glaciation seems to have produced in the Alps.

  11. EAARL Submarine Topography - Northern Florida Keys Reef Tract

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Travers, Laurinda J.; Wilson, Iris

    2007-01-01

    This Web site contains 32 Lidar-derived bare earth topography maps and GIS files for the Northern Florida Keys Reef Tract. These lidar-derived submarine topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

  12. EAARL submarine topography: Florida Keys National Marine Sanctuary

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Woolard, Jason; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

    2007-01-01

    This Web site contains 46 Lidar-derived submarine topography maps and GIS files for the Florida Keys National Marine Sanctuary. These Lidar-derived submarine topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Oceanic and Atmospheric Administration (NOAA), Remote Sensing Division, the National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography within cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to coastal resource managers.

  13. Tropical Pacific response to continental ice sheet topography

    NASA Astrophysics Data System (ADS)

    Lee, Shih-Yu; Chiang, John C. H.; Chang, Ping

    2015-05-01

    The last glacial maximum was marked by maximum land ice extent and lowest greenhouse gases concentration during the last ice age. We explore the impact of glacial continental ice sheet topography on the large-scale tropical ocean-atmosphere climate, in particular the tropical Pacific, in an intermediate complexity coupled model. Increasing the thickness of continental ice sheets causes a southward displaced Pacific Intertropical Convergence Zone (ITCZ) and a strengthening (weakening) of northern (southern) hemisphere winter Hadley cell. The equatorial zonal sea surface temperature gradient weakened with an increased continental ice sheets thickness, the reduction being caused by cooling in the western equatorial Pacific and warming in the eastern equatorial Pacific. The evolution of the tropical climate with changing ice thickness has distinct quasi-linear and nonlinear parts. While the linear part is a direct response to the ice topographic changes, the nonlinear part was a result of the tropical thermocline adjustment. Our analysis of a fully-coupled transient deglacial simulation strongly indicates the dominant role of ice sheet topography in determining the deglacial evolution of the simulated Pacific climate. The thickness of continental ice sheet, separate from ice albedo effect, has significant impact on the tropical ocean-atmosphere climate in particular with the meridional displacement in the Pacific ITCZ. The altered circulation states seen in the model may aid understanding of the relationship between tropical and high-latitude climate records in glacial-interglacial cycles.

  14. Topography and Areal Organization of Mouse Visual Cortex

    PubMed Central

    Garrett, Marina E.; Nauhaus, Ian; Marshel, James H.

    2014-01-01

    To guide future experiments aimed at understanding the mouse visual system, it is essential that we have a solid handle on the global topography of visual cortical areas. Ideally, the method used to measure cortical topography is objective, robust, and simple enough to guide subsequent targeting of visual areas in each subject. We developed an automated method that uses retinotopic maps of mouse visual cortex obtained with intrinsic signal imaging (Schuett et al., 2002; Kalatsky and Stryker, 2003; Marshel et al., 2011) and applies an algorithm to automatically identify cortical regions that satisfy a set of quantifiable criteria for what constitutes a visual area. This approach facilitated detailed parcellation of mouse visual cortex, delineating nine known areas (primary visual cortex, lateromedial area, anterolateral area, rostrolateral area, anteromedial area, posteromedial area, laterointermediate area, posterior area, and postrhinal area), and revealing two additional areas that have not been previously described as visuotopically mapped in mice (laterolateral anterior area and medial area). Using the topographic maps and defined area boundaries from each animal, we characterized several features of map organization, including variability in area position, area size, visual field coverage, and cortical magnification. We demonstrate that higher areas in mice often have representations that are incomplete or biased toward particular regions of visual space, suggestive of specializations for processing specific types of information about the environment. This work provides a comprehensive description of mouse visuotopic organization and describes essential tools for accurate functional localization of visual areas. PMID:25209296

  15. Feasibility of skin surface elastography by tracking skin surface topography

    NASA Astrophysics Data System (ADS)

    Coutts, Louise V.; Miller, Naomi R.; Harland, Christopher C.; Bamber, Jeffrey C.

    2013-12-01

    Recent advances have led to a multitude of image modalities being used for visualization of tissue stiffness. High-resolution images of tissue stiffness are desirable, as they have the potential to provide useful diagnostic information. A noncontact optical imaging method has the attractions of low cost, simplicity, and utility when skin contact is undesirable. However, previous optical techniques have required the application of paint or ink to the surface of the skin and so have required contact. Therefore, the present study assessed the feasibility of tracking skin surface topography to produce elastograms. The study showed, by analyzing a variety of silicone skin surface replicas from various body sites of subjects of different ages, that skin surface elastography by tracking surface topography would be feasible. The study further showed that the quality of the strain images can be optimized by measuring skin line pattern frequency. Skin samples with high skin line frequency will achieve best spatial resolution, in the order of 1 mm, comparable to contact techniques reported previously. A mechanically inhomogeneous silicone replica was then imaged, illustrating the technique's ability to detect strain contrast. Finally, the feasibility of implementing the technique in vivo was illustrated using a single pigmented skin lesion.

  16. Synchrotron X-ray topography of electronic materials.

    PubMed

    Tuomi, T

    2002-05-01

    Large-area transmission, transmission section, large-area back-reflection, back-reflection section and grazing-incidence topography are the geometries used when recording high-resolution X-ray diffraction images with synchrotron radiation from a bending magnet, a wiggler or an undulator of an electron or a positron storage ring. Defect contrast can be kinematical, dynamical or orientational even in the topographs recorded on the same film at the same time. In this review article limited to static topography experiments, examples of defect studies on electronic materials cover the range from voids and precipitates in almost perfect float-zone and Czochralski silicon, dislocations in gallium arsenide grown by the liquid-encapsulated Czochralski technique, the vapour-pressure controlled Czochralski technique and the vertical-gradient freeze technique, stacking faults and micropipes in silicon carbide to misfit dislocations in epitaxic heterostructures. It is shown how synchrotron X-ray topographs of epitaxic laterally overgrown gallium arsenide layer structures are successfully explained by orientational contrast. PMID:11972374

  17. Variation in road surface temperature due to topography and wind

    NASA Astrophysics Data System (ADS)

    Gustavsson, T.

    1990-12-01

    The present study involves a discussion of nocturnal temperature variation due to topography and prevailing wind speed. It is part of the ongoing project “Applied climatology for increased traffic safety and road maintenance”, which aims at a development of a local climatological model applicable to winter road conditions. The temperature recordings which are used are from sensors in the Swedish Road Weather Information System in the county of Skaraborg. During clear and calm nights, local air temperature differences have been related to different topographical environments. The main factors resulting in large temperature differences are the effect of wind shelter, stagnation or production of cold air, and of cold air advection. Variation in air temperatures during clear and windy nights has also been studied. At wind speeds higher than 4 5 m/s, the temperature variation is low. With decreasing wind speed the variation in temperature increases, but only for sensor sites which have some wind shelter by topography or vegetation. The air temperature variation which develops during clear nights affects the road surface temperature. In this paper, the connection between road surface temperature differences and air temperature variation is discussed. A linear relationship between the two variables exists.

  18. X-Ray Topography Techniques for Defect Characterization of Crystals

    NASA Astrophysics Data System (ADS)

    Raghothamachar, Balaji; Dudley, Michael; Dhanaraj, Govindhan

    X-ray topography is the general term for a family of x-ray diffraction imaging techniques capable of providing information on the nature and distribution of structural defects such as dislocations, inclusions/precipitates, stacking faults, growth sector boundaries, twins, and low-angle grain boundaries in single-crystal materials. From the first x-ray diffraction image, recorded by Berg in 1931, to the double-crystal technique developed by Bond and Andrus in 1952 and the transmission technique developed by Lang in 1958 through to present-day synchrotron-radiation-based techniques, x-ray topography has evolved into a powerful, nondestructive method for the rapid characterization of large single crystals of a wide range of chemical compositions and physical properties, such as semiconductors, oxides, metals, and organic materials. Different defects are readily identified through interpretation of contrast using well-established kinematical and dynamical theories of x-ray diffraction. This method is capable of imaging extended defects in the entire volume of the crystal and in some cases in wafers with devices fabricated on them. It is well established as an indispensable tool for the development of growth techniques for highly perfect crystals (for, e.g., Czochralski growth of silicon) for semiconductor and electronic applications. The capability of in situ characterization during crystal growth, heat treatment, stress application, device operation, etc. to study the generation, interaction, and propagation of defects makes it a versatile technique to study many materials processes.

  19. The contribution of eddies to striations in absolute dynamic topography

    NASA Astrophysics Data System (ADS)

    Buckingham, C. E.; Cornillon, P. C.

    2013-01-01

    AbstractDistinct 4 year averages of absolute dynamic <span class="hlt">topography</span> reveal striations in all ocean basins during 1993-2008. Striations are alternating mesoscale jet-like structures observed in time-averaged zonal geostrophic velocity, u>¯. They are characterized by speeds O(1 cm s-1) and are nominally separated by 200 km in the meridional direction. Similar patterns have been observed in sea level anomaly, mean dynamic <span class="hlt">topography</span>, and Argo float measurements. Use of a tracked-eddy database in concert with a contour identification and eddy removal algorithm demonstrates that eddies are a dominant source of striations in u>¯ in the South Pacific (20°S-50°S, 200°E-280°E). Eddies with lifetimes ? 4 weeks account for 46-57% of the variance in u>¯ and correlation coefficients between total and eddy-only u>¯ are 0.90-0.93. Attention is given to the ability of the algorithm to correctly identify eddies and suggests that a more appropriate bound on the variance due to eddies is ˜ 30-70%. This permits the existence of latent zonal jets and/or ?-plumes. Additional findings of the study include (1) a large number of eddies having a broad range of amplitudes and scales contribute most to the eddy-induced patterns and (2) the standard deviation of u>¯ does not decay inversely with averaging period as proposed by a model of random eddies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001SPIE.4186..827H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001SPIE.4186..827H"><span id="translatedtitle">Effects of shifter edge <span class="hlt">topography</span> on through focus performance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hotta, Shoji; Pistor, Thomas V.; Adam, Konstantinos; Neureuther, Andrew R.</p> <p>2001-01-01</p> <p>We have investigated the effects of the <span class="hlt">topography</span> of the phase-shifting mask on the aerial image characteristics in DUV lithography. The calculation of near fields is carried out through simulation of the mask with TEMPEST and linking the resultant near fields to EM-Aerial for imaging. It is shown that the Fourier spectrum for an alternating phase-shifting mask can be decomposed into Fourier spectra for single openings. The amplitude and phase of the diffraction orders for the single opening are utilized for the systematic analysis of the shifter edge <span class="hlt">topography</span>. The analysis framework developed in this paper clearly identifies the effects of the wall of the phase shifter, the residual transmittance through the chromium area, and the cross-talk between adjacent features. This analysis framework also allows these effects be merged in design. The near field profile in the vicinity of the shifter wall is also investigated for different feature sizes, and the optimum design for different feature sizes is discussed. The effect of the wall angle profile is shown to be acceptable.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatGe...8..789G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatGe...8..789G"><span id="translatedtitle">Minimal erosion of Arctic alpine <span class="hlt">topography</span> during late Quaternary glaciation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gjermundsen, Endre F.; Briner, Jason P.; Akçar, Naki; Foros, Jørn; Kubik, Peter W.; Salvigsen, Otto; Hormes, Anne</p> <p>2015-10-01</p> <p>The alpine <span class="hlt">topography</span> observed in many mountainous regions is thought to have formed during repeated glaciations of the Quaternary period. Before this time, landscapes had much less relief. However, the spatial patterns and rates of Quaternary exhumation at high latitudes--where cold-based glaciers may protect rather than erode landscapes--are not fully quantified. Here we determine the exposure and burial histories of rock samples from eight summits of steep alpine peaks in northwestern Svalbard (79.5° N) using analyses of 10Be and 26Al concentrations. We find that the summits have been preserved for at least the past one million years. The antiquity of Svalbard’s alpine landscape is supported by the preservation of sediments older than one million years along a fjord valley, which suggests that both mountain summits and low-elevation landscapes experienced very low erosion rates over the past million years. Our findings support the establishment of northwestern Svalbard’s alpine <span class="hlt">topography</span> during the early Quaternary. We suggest that, as the Quaternary ice age progressed, glacial erosion in the Arctic became inefficient and confined to ice streams, and high-relief alpine landscapes were preserved by minimally erosive glacier armour.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120008707','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120008707"><span id="translatedtitle">Lunar <span class="hlt">Topography</span>: Results from the Lunar Orbiter Laser Altimeter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Neumann, Gregory; Smith, David E.; Zuber, Maria T.; Mazarico, Erwan</p> <p>2012-01-01</p> <p>The Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO) has been operating nearly continuously since July 2009, accumulating over 6 billion measurements from more than 2 billion in-orbit laser shots. LRO's near-polar orbit results in very high data density in the immediate vicinity of the lunar poles, with full coverage at the equator from more than 12000 orbital tracks averaging less than 1 km in spacing at the equator. LRO has obtained a global geodetic model of the lunar <span class="hlt">topography</span> with 50-meter horizontal and 1-m radial accuracy in a lunar center-of-mass coordinate system, with profiles of <span class="hlt">topography</span> at 20-m horizontal resolution, and 0.1-m vertical precision. LOLA also provides measurements of reflectivity and surface roughness down to its 5-m laser spot size. With these data LOLA has measured the shape of all lunar craters 20 km and larger. In the proposed extended mission commencing late in 2012, LOLA will concentrate observations in the Southern Hemisphere, improving the density of the polar coverage to nearly 10-m pixel resolution and accuracy to better than 20 m total position error. Uses for these data include mission planning and targeting, illumination studies, geodetic control of images, as well as lunar geology and geophysics. Further improvements in geodetic accuracy are anticipated from the use of re ned gravity fields after the successful completion of the Gravity Recovery and Interior Laboratory (GRAIL) mission in 2012.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70047737','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70047737"><span id="translatedtitle">Ground motion in the presence of complex <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hartzell, Stephen; Meremonte, Mark; Ramírez-Guzmán, Leonardo; McNamara, Daniel</p> <p>2014-01-01</p> <p>To study the influence of <span class="hlt">topography</span> on ground motion, eight seismic recorders were deployed for a period of one year over Poverty Ridge on the east side of the San Francisco Bay Area, California. This location is desirable because of its proximity to local earthquake sources and the significant topographic relief of the array (439 m). Topographic amplification is evaluated as a function of frequency using a variety of methods, including reference?site?based spectral ratios and single?station horizontal?to?vertical spectral ratios using both shear waves from earthquakes and ambient noise. Field observations are compared with the predicted ground motion from an accurate digital model of the <span class="hlt">topography</span> and a 3D local velocity model. Amplification factors from the theoretical calculations are consistent with observations. The fundamental resonance of the ridge is prominently observed in the spectra of data and synthetics; however, higher?frequency peaks are also seen primarily for sources in line with the major axis of the ridge, perhaps indicating higher resonant modes. Excitations of lateral ribs off of the main ridge are also seen at frequencies consistent with their dimensions. The favored directions of resonance are shown to be transverse to the major axes of the topographic features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900049448&hterms=Asthenosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DAsthenosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900049448&hterms=Asthenosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DAsthenosphere"><span id="translatedtitle">Internal structure of Io and the global distribution of its <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ross, M. N.; Schubert, G.; Spohn, T.; Gaskell, R. W.</p> <p>1990-01-01</p> <p>A global <span class="hlt">topography</span> is presently calculated for two multilayer Io models in which dissipation occurs in a viscous asthenosphere and a solid mantle: (1) a 'thermal swell' model, in which <span class="hlt">topography</span> and heat flow are positively correlated, and (2) a 'differentiated lithosphere' model, in which <span class="hlt">topography</span> and heat flow are negatively correlated. Both the polar <span class="hlt">topography</span> and the hypsometric distribution of elevations in the differentiated lithosphere model are better matched with observations than the thermal swell model. The shift of the equatorial basin-swell pattern indicates a recent zonal rotation of about 25 deg for Io's lithosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22722085','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22722085"><span id="translatedtitle">Eye shape and retinal <span class="hlt">topography</span> in owls (Aves: Strigiformes).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lisney, Thomas J; Iwaniuk, Andrew N; Bandet, Mischa V; Wylie, Douglas R</p> <p>2012-01-01</p> <p>The eyes of vertebrates show adaptations to the visual environments in which they evolve. For example, eye shape is associated with activity pattern, while retinal <span class="hlt">topography</span> is related to the symmetry or 'openness' of the habitat of a species. Although these relationships are well documented in many vertebrates including birds, the extent to which they hold true for species within the same avian order is not well understood. Owls (Strigiformes) represent an ideal group for the study of interspecific variation in the avian visual system because they are one of very few avian orders to contain species that vary in both activity pattern and habitat preference. Here, we examined interspecific variation in eye shape and retinal <span class="hlt">topography</span> in nine species of owl. Eye shape (the ratio of corneal diameter to eye axial length) differed among species, with nocturnal species having relatively larger corneal diameters than diurnal species. All the owl species have an area of high retinal ganglion cell (RGC) density in the temporal retina and a visual streak of increased cell density extending across the central retina from temporal to nasal. However, the organization and degree of elongation of the visual streak varied considerably among species and this variation was quantified using H:V ratios. Species that live in open habitats and/or that are more diurnally active have well-defined, elongated visual streaks and high H:V ratios (3.88-2.33). In contrast, most nocturnal and/or forest-dwelling owls have a poorly defined visual streak, a more radially symmetrical arrangement of RGCs and lower H:V ratios (1.77-1.27). The results of a hierarchical cluster analysis indicate that the apparent interspecific variation is associated with activity pattern and habitat as opposed to the phylogenetic relationships among species. In seven species, the presence of a fovea was confirmed and it is suggested that all strigid owls may possess a fovea, whereas the tytonid barn owl (Tyto alba) does not. A size-frequency analysis of cell soma area indicates that a number of different RGC classes are represented in owls, including a population of large RGCs (cell soma area >150 µm(2)) that resemble the giant RGCs reported in other vertebrates. In conclusion, eye shape and retinal <span class="hlt">topography</span> in owls vary among species and this variation is associated with different activity patterns and habitat preferences, thereby supporting similar observations in other vertebrates. PMID:22722085</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/ds/399/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/ds/399/"><span id="translatedtitle">EAARL Coastal <span class="hlt">Topography</span> - Northern Gulf of Mexico, 2007: First Surface</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Smith, Kathryn E.L.; Nayegandhi, Amar; Wright, C. Wayne; Bonisteel, Jamie M.; Brock, John C.</p> <p>2009-01-01</p> <p>These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) elevation data were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. The project provides highly detailed and accurate datasets of select barrier islands and peninsular regions of Louisiana, Mississippi, Alabama, and Florida, acquired June 27-30, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, <span class="hlt">topography</span>, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal <span class="hlt">topography</span> within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial <span class="hlt">topography</span>. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/ds/665/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/ds/665/"><span id="translatedtitle">EAARL coastal <span class="hlt">topography</span>--Alligator Point, Louisiana, 2010</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nayegandhi, Amar; Bonisteel-Cormier, J.M.; Wright, C.W.; Brock, J.C.; Nagle, D.B.; Vivekanandan, Saisudha; Fredericks, Xan; Barras, J.A.</p> <p>2012-01-01</p> <p>This project provides highly detailed and accurate datasets of a portion of Alligator Point, Louisiana, acquired on March 5 and 6, 2010. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the National Aeronautics and Space Administration (NASA) Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, <span class="hlt">topography</span>, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine aircraft, but the instrument was deployed on a Pilatus PC-6. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal <span class="hlt">topography</span> within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial <span class="hlt">topography</span>. Specialized filtering algorithms have been implemented to determine the "bare earth" under vegetation from a point cloud of last return elevations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhD...48T5308E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhD...48T5308E"><span id="translatedtitle">Evolution of <span class="hlt">topography</span> and material removal during nanoscale grinding</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eder, S. J.; Cihak-Bayr, U.; Vernes, A.; Betz, G.</p> <p>2015-11-01</p> <p>In this work we perform molecular dynamics simulations to quantify and parametrize the evolution of a bcc Fe work piece <span class="hlt">topography</span> during nanometric grinding with multiple hard abrasive particles. The final surface quality depends on both the normal pressure and the abrasive geometry. We fit the time development of the substrate’s root mean squared roughness to an exponential function, allowing the definition of a run-in regime, during which the surface ‘forgets’ about its initial state, and a steady-state regime where the roughness no longer changes. The time constants associated with smoothing and material removal are almost inversely proportional to each other, highlighting the distinctiveness of these two simultaneously occurring processes. We also describe an attempt to reduce the time required to achieve the smoothest possible surface finish by periodically re-adjusting the normal pressure during the grinding process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999Geo....27..563G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999Geo....27..563G"><span id="translatedtitle">Plate detachment, asthenosphere upwelling, and <span class="hlt">topography</span> across subduction zones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gvirtzman, Zohar; Nur, Amos</p> <p>1999-06-01</p> <p>This study analyzes the <span class="hlt">topography</span> across subduction zones, considering the separate contributions of the crust and the mantle lithosphere to the observed surface elevation. We have found a transition from a region where the overriding plate is coupled to the descending slab and pulled down along with it to a region where the overriding plate floats freely on the asthenosphere. When the subducting slab retreats oceanward rapidly this transition is abrupt, and the edge of the overriding plate is uplifted. We propose that at some point during rapid slab rollback the overriding plate detaches and rebounds like a boat released from its keel. This event is associated with suction of asthenospheric material into the gap that is opened between the plates up to the base of the crust. As a result, the forearc uplifts, and magmatism in the arc increases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940008862','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940008862"><span id="translatedtitle">The American Geophysical Union Chapman Conference on Tectonics and <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1992-01-01</p> <p>The Chapman Conference on Tectonics and <span class="hlt">Topography</span> was held 31 Aug. - 4 Sep. 1992. The conference was designed to bring together disparate groups of earth scientists who increasingly found themselves working on similar problems but in relative isolation. Thus, process geomorphologists found themselves face-to-face with numerical modelers and field geomorphologists, hydrologists encountered geologists, and tectonophysicists found people with related data. The keynote speakers represented a wide variety of disciplines, all of which were relevant to the interdisciplinary theme of the conference. One of the most surprising issues that surfaced was the relative dearth of data that exists about erosion--process and rates. This was exacerbated by a reminder that erosion is critical to the evaluation of surface uplift.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/559930','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/559930"><span id="translatedtitle">Friction and atomically resolved <span class="hlt">topography</span> in AFM imaging</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ogletree, D.F.; Carpick, R.W.; Salmeron, M.</p> <p>1997-12-31</p> <p>Topographic AFM images that resolve the atomic lattice of the sample have been reported for many different materials under a wide range of experimental conditions, including experiments in ambient environments, in liquids, in electrochemical control and in ultra-high vacuum. Lattice resolution has been observed for layered materials, alkali-hailide crystals, metals, oxides, molecular crystals and also for ordered molecular films produced by self-assembly or by Langmuir-Blodgett techniques. We will show that this apparent topographic resolution can be explained as a by product of {open_quotes}stick-slip{close_quotes} friction on the atomic level. Numerical simulations of AFM friction and topographic images will be presented to illustrate the relation between stick-slip friction and <span class="hlt">topography</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760009913','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760009913"><span id="translatedtitle">Geologic structure of shallow maria. [<span class="hlt">topography</span> of lunar maria</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dehon, R. A.; Waskom, J. A.</p> <p>1975-01-01</p> <p>Isopach maps and structural contour maps of the eastern mare basins (30 deg N to 30 deg S; 0 deg to 100 deg E), constructed from measurements of partially buried craters, are presented and discussed. The data, which are sufficiently scattered to yield gross thickness variations, are restricted to shallow maria with less than 1500-2000 m of mare basalts. The average thickness of basalt in the irregular maria is between 200 and 400 m. Correlations between surface <span class="hlt">topography</span>, basalt thickness, and basin floor structure are apparent in most of the basins that were studied. The mare surface is commonly depressed in regions of thick mare basalts; mare ridges are typically located in regions of pronounced thickness changes; and arcuate mare rilles are confined to thin mare basalts. Most surface structures are attributed to shallow stresses developed within the mare basalts during consolidation and volume reduction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991P%26SS...39..225B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991P%26SS...39..225B"><span id="translatedtitle"><span class="hlt">Topography</span> of the Martian tropical regions with ISM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bibring, J.-P.; Erard, S.; Gondet, B.; Langevin, Y.; Soufflot, A.; Combes, M.; Cara, C.; Drossart, P.; Encrenaz, T.; Lellouch, E.; Rosenqvist, J.; Moroz, V. I.; Dyachkov, A. V.; Grygoriev, A. V.; Havinson, N. G.; Khatuntsev, I. V.; Kiselev, A. V.; Ksanfomality, L. V.; Nikolsky, Yu. V.; Masson, P.; Forni, O.; Sotin, C.</p> <p>1991-02-01</p> <p>The measurement of the CO2 column density on Mars, from the 2-micron band, in the Phobos/ISM spectra allows the determination of the altitude of the surface of Mars, with a horizontal spatial resolution of 20 km. The uncertainties involved in this method are described and compared with previous measurements of the Martian <span class="hlt">topography</span>. Several topographic maps have been calculated, in the region of the high Martian volcanoes and Valles Marineris. Comparison with topographic maps derived from Mariner 9 and Viking measurements shows a good agreement. An average accuracy of about 400 m is obtained, which constitutes a significant improvement, compared with previous altimetry errors, of the order of 1 km. The method has a uniform accuracy over a full observation sequence (about 3000 km wide), and is complementary to the Viking photogrammetric measurements, more accurate on a 100 km scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16741111','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16741111"><span id="translatedtitle">Mass and local <span class="hlt">topography</span> measurements of Itokawa by Hayabusa.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abe, Shinsuke; Mukai, Tadashi; Hirata, Naru; Barnouin-Jha, Olivier S; Cheng, Andrew F; Demura, Hirohide; Gaskell, Robert W; Hashimoto, Tatsuaki; Hiraoka, Kensuke; Honda, Takayuki; Kubota, Takashi; Matsuoka, Masatoshi; Mizuno, Takahide; Nakamura, Ryosuke; Scheeres, Daniel J; Yoshikawa, Makoto</p> <p>2006-06-01</p> <p>The ranging instrument aboard the Hayabusa spacecraft measured the surface <span class="hlt">topography</span> of asteroid 25143 Itokawa and its mass. A typical rough area is similar in roughness to debris located on the interior wall of a large crater on asteroid 433 Eros, which suggests a surface structure on Itokawa similar to crater ejecta on Eros. The mass of Itokawa was estimated as (3.58 +/- 0.18) x 10(10) kilograms, implying a bulk density of (1.95 +/- 0.14) grams per cubic centimeter for a volume of (1.84 +/- 0.09) x 10(7) cubic meters and a bulk porosity of approximately 40%, which is similar to that of angular sands, when assuming an LL (low iron chondritic) meteorite composition. Combined with surface observations, these data indicate that Itokawa is the first subkilometer-sized small asteroid showing a rubble-pile body rather than a solid monolithic asteroid. PMID:16741111</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1051628','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1051628"><span id="translatedtitle">Characterization of Mo/Si multilayer growth on stepped <span class="hlt">topographies</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Boogaard, A. J. R. vcan den; Louis, E.; Zoethout, E.; Goldberg, K. A.; Bijkerk, F.</p> <p>2011-08-31</p> <p>Mo/Si multilayer mirrors with nanoscale bilayer thicknesses have been deposited on stepped substrate <span class="hlt">topographies</span>, using various deposition angles. The multilayer morphology at the stepedge region was studied by cross section transmission electron microscopy. A transition from a continuous- to columnar layer morphology is observed near the step-edge, as a function of the local angle of incidence of the deposition flux. Taking into account the corresponding kinetics and anisotropy in layer growth, a continuum model has been developed to give a detailed description of the height profiles of the individual continuous layers. Complementary optical characterization of the multilayer system using a microscope operating in the extreme ultraviolet wavelength range, revealed that the influence of the step-edge on the planar multilayer structure is restricted to a region within 300 nm from the step-edge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPSC...10..803L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPSC...10..803L"><span id="translatedtitle">Enceladus' internal ocean constrained from Cassini gravity and <span class="hlt">topography</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lefevre, A.; Tobie, G.; Choblet, G.; Cadek, O.; Mitri, G.; Massé, M.; Behounkova, M.</p> <p>2015-10-01</p> <p>The intense activity at the south pole of Enceladus hints at an interna l water reservoir. The detection of sodium and potassium salts (about 1%) in icy grains emanating from Enceladus' south polar faults [1] indicates that the plume source is most likely connected to a salty subsurface ocean. The recent discovery of silicon-rich particles originating from Enceladus further indicates that hydrothermal interactions is currently occurring at the base of the ocean, and that hydrothermal products are quickly transferred to the plume source[2]. Based on <span class="hlt">topography</span> and gravity data collected by the Cassini spacecraft[3, 4], this depth of ice/ocean interface is estimated to about 30-40 km underneath the South Pole. However the depth of ocean/rock interface as well as the extension of the ocean still remains unconstrained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.agu.org/pubs/crossref/2010/2010EO070001.shtml','USGSPUBS'); return false;" href="http://www.agu.org/pubs/crossref/2010/2010EO070001.shtml"><span id="translatedtitle">Forecasting hurricane impact on coastal <span class="hlt">topography</span>: Hurricane Ike</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Plant, Nathaniel G.; Stockdon, Hilary F.; Sallenger, Asbury H., Jr.; Turco, Michael J.; East, Jeffery W.; Taylor, Arthur A.; Shaffer, Wilson A.</p> <p>2010-01-01</p> <p>Extreme storms can have a profound impact on coastal <span class="hlt">topography</span> and thus on ecosystems and human-built structures within coastal regions. For instance, landfalls of several recent major hurricanes have caused significant changes to the U.S. coastline, particularly along the Gulf of Mexico. Some of these hurricanes (e.g., Ivan in 2004, Katrina and Rita in 2005, and Gustav and Ike in 2008) led to shoreline position changes of about 100 meters. Sand dunes, which protect the coast from waves and surge, eroded, losing several meters of elevation in the course of a single storm. Observations during these events raise the question of how storm-related changes affect the future vulnerability of a coast.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20150005639&hterms=water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26Nf%3DPublication-Date%257CLT%2B20121231%26N%3D0%26No%3D20%26Ntt%3Dwater','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20150005639&hterms=water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26Nf%3DPublication-Date%257CLT%2B20121231%26N%3D0%26No%3D20%26Ntt%3Dwater"><span id="translatedtitle">The Proposed Surface Water and Ocean <span class="hlt">Topography</span> (SWOT) Mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fu, Lee-Lueng; Alsdorf, Douglas; Rodriguez, Ernesto; Morrow, Rosemary; Mognard, Nelly; Vaze, Parag; Lafon, Thierry</p> <p>2012-01-01</p> <p>A new space mission concept called Surface Water and Ocean <span class="hlt">Topography</span> (SWOT) is being developed jointly by a collaborative effort of the international oceanographic and hydrological communities for making high-resolution measurement of the water elevation of both the ocean and land surface water to answer the questions about the oceanic submesoscale processes and the storage and discharge of land surface water. The key instrument payload would be a Ka-band radar interferometer capable of making high-resolution wide-swath altimetry measurement. This paper describes the proposed science objectives and requirements as well as the measurement approach of SWOT, which is baselined to be launched in 2019. SWOT would demonstrate this new approach to advancing both oceanography and land hydrology and set a standard for future altimetry missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70121561','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70121561"><span id="translatedtitle">Recent and relict <span class="hlt">topography</span> of Boo Bee patch reef, Belize</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Halley, R.B.; Shinn, E.A.; Hudson, J.H.; Lidz, B.</p> <p>1977-01-01</p> <p>Five core borings were taken on and around Boo Bee Patch Reef to better understand the origin of such shelf lagoon reefs. The cores reveal 4 stages of development: (1) subaerial exposure of a Pleistocene "high" having about 8 meters of relief, possibly a Pleistocene patch reef; (2) deposition of peat and impermeable terrigenous clay 3 meters thick around the high; (3) initiation of carbonate sediment production by corals and algae on the remaining 5 meters of hard Pleistocene <span class="hlt">topography</span> and carbonate mud on the surrounding terrigenous clay; and (4) accelerated organic accumulation on the patch reef. Estimates of patch reef sedimentation rates (1.6 m/1000 years) are 3 to 4 times greater than off-reef sedimentation rates (0.4-0.5 m/1000 years). During periods of Pleistocene sedimentation on the Belize shelf, lagoon patch reefs may have grown above one another, stacking up to form reef accumulation of considerable thickness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000053500','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000053500"><span id="translatedtitle">The Shuttle Radar <span class="hlt">Topography</span> Mission: A Global DEM</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farr, Tom G.; Kobrick, Mike</p> <p>2000-01-01</p> <p>Digital topographic data are critical for a variety of civilian, commercial, and military applications. Scientists use Digital Elevation Models (DEM) to map drainage patterns and ecosystems, and to monitor land surface changes over time. The mountain-building effects of tectonics and the climatic effects of erosion can also be modeled with DEW The data's military applications include mission planning and rehearsal, modeling and simulation. Commercial applications include determining locations for cellular phone towers, enhanced ground proximity warning systems for aircraft, and improved maps for backpackers. The Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM) (Fig. 1), is a cooperative project between NASA and the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense. The mission is designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and south latitude. The DEM will have 30 m pixel spacing and about 15 m vertical errors.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1048123','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1048123"><span id="translatedtitle">SRF Cavity Surface <span class="hlt">Topography</span> Characterization Using Replica Techniques</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>C. Xu, M.J. Kelley, C.E. Reece</p> <p>2012-07-01</p> <p>To better understand the roll of <span class="hlt">topography</span> on SRF cavity performance, we seek to obtain detailed topographic information from the curved practical cavity surfaces. Replicas taken from a cavity interior surface provide internal surface molds for fine Atomic Force Microscopy (AFM) and stylus profilometry. In this study, we confirm the replica resolution both on surface local defects such as grain boundary and etching pits and compare the surface uniform roughness with the aid of Power Spectral Density (PSD) where we can statistically obtain roughness parameters at different scales. A series of sampling locations are at the same magnetic field chosen at the same latitude on a single cell cavity to confirm the uniformity. Another series of sampling locations at different magnetic field amplitudes are chosen for this replica on the same cavity for later power loss calculation. We also show that application of the replica followed by rinsing does not adversely affect the cavity performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA04174&hterms=World+Top+Cities&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DWorld%2527s%2BTop%2BCities','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA04174&hterms=World+Top+Cities&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DWorld%2527s%2BTop%2BCities"><span id="translatedtitle">New Orleans <span class="hlt">Topography</span>, Radar Image with Colored Height</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p>[figure removed for brevity, see original site] Click on the image for the animation <p/> <i>About the animation</i>: This simulated view of the potential effects of storm surge flooding on Lake Pontchartrain and the New Orleans area was generated with data from the Shuttle Radar <span class="hlt">Topography</span> Mission. Although it is protected by levees and sea walls against storm surges of 18 to 20 feet, much of the city is below sea level, and flooding due to storm surges caused by major hurricanes is a concern. The animation shows regions that, if unprotected, would be inundated with water. The animation depicts flooding in one-meter increments. <p/> <i>About the image</i>: The city of New Orleans, situated on the southern shore of Lake Pontchartrain, is shown in this radar image from the Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM). In this image bright areas show regions of high radar reflectivity, such as from urban areas, and elevations have been coded in color using height data also from the SRTM mission. Dark green colors indicate low elevations, rising through yellow and tan, to white at the highest elevations. <p/> New Orleans is near the center of this scene, between the lake and the Mississippi River. The line spanning the lake is the Lake Pontchartrain Causeway, the world's longest overwater highway bridge. Major portions of the city of New Orleans are actually below sea level, and although it is protected by levees and sea walls that are designed to protect against storm surges of 18 to 20 feet, flooding during storm surges associated with major hurricanes is a significant concern. <p/> Data used in this image were acquired by the Shuttle Radar <span class="hlt">Topography</span> Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, Washington, D.C. <p/> Location: 30.2 degrees North latitude, 90.1 degrees East longitude Orientation: North toward the top, Mercator projection Size: 80.3 by 68.0 kilometers (49.9 by 42.3 miles) Image Data: Radar image and colored Shuttle Radar <span class="hlt">Topography</span> Mission elevation model Date Acquired: February 2000</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EOSTr..94S.131B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EOSTr..94S.131B"><span id="translatedtitle">Eddies contribute to striations in sea surface <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balcerak, Ernie</p> <p>2013-03-01</p> <p>Scientists recently observed striations in sea surface <span class="hlt">topography</span> in all ocean basins. These striations appear as alternating mesoscale jet-like structures; they have speeds on the order of 1 centimeter per second and are typically separated by about 200 kilometers in the meridional direction. The cause of these striations has been debated. Contributing to this scientific discussion, Buckingham and Cornillon used a database of tracked eddies and a contour identification and eddy removal algorithm to show that eddies are a significant source of striations. The authors noted that a small portion of the energy was unaccounted for by propagating eddies, allowing for the existence of weak zonal flows. (Journal of Geophysical Research-Oceans, doi:10.1029/2012JC008231, 2013)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25770899','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25770899"><span id="translatedtitle">Scaffolds for hand tissue engineering: the importance of surface <span class="hlt">topography</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kloczko, E; Nikkhah, D; Yildirimer, L</p> <p>2015-11-01</p> <p>Tissue engineering is believed to have great potential for the reconstruction of the hand after trauma, congenital absence and tumours. Due to the presence of multiple distinct tissue types, which together function in a precisely orchestrated fashion, the hand counts among the most complex structures to regenerate. As yet the achievements have been limited. More recently, the focus has shifted towards scaffolds, which provide a three-dimensional framework to mimic the natural extracellular environment for specific cell types. In particular their surface structures (or <span class="hlt">topographies</span>) have become a key research focus to enhance tissue-specific cell attachment and growth into fully functioning units. This article reviews the current understanding in hand tissue engineering before focusing on the potential for scaffold topographical features on micro- and nanometre scales to achieve better functional regeneration of individual and composite tissues. PMID:25770899</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AIPC..907...64P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AIPC..907...64P"><span id="translatedtitle">Different Approach to the Aluminium Oxide <span class="hlt">Topography</span> Characterisation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poljacek, Sanja Mahovic; Gojo, Miroslav; Raos, Pero; Stoic, Antun</p> <p>2007-04-01</p> <p>Different surface topographic techniques are being widely used for quantitative measurements of typical industrial aluminium oxide surfaces. In this research, specific surface of aluminium oxide layer on the offset printing plate has been investigated by using measuring methods which have previously not been used for characterisation of such surfaces. By using two contact instruments and non-contact laser profilometer (LPM) 2D and 3D roughness parameters have been defined. SEM micrographs of the samples were made. Results have shown that aluminium oxide surfaces with the same average roughness value (Ra) and mean roughness depth (Rz) typically used in the printing plate surface characterisation, have dramatically different surface <span class="hlt">topographies</span>. According to the type of instrument specific roughness parameters should be used for defining the printing plate surfaces. New surface roughness parameters were defined in order to insure detailed characterisation of the printing plates in graphic reproduction process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21057071','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21057071"><span id="translatedtitle">Different Approach to the Aluminium Oxide <span class="hlt">Topography</span> Characterisation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Poljacek, Sanja Mahovic; Gojo, Miroslav; Raos, Pero; Stoic, Antun</p> <p>2007-04-07</p> <p>Different surface topographic techniques are being widely used for quantitative measurements of typical industrial aluminium oxide surfaces. In this research, specific surface of aluminium oxide layer on the offset printing plate has been investigated by using measuring methods which have previously not been used for characterisation of such surfaces. By using two contact instruments and non-contact laser profilometer (LPM) 2D and 3D roughness parameters have been defined. SEM micrographs of the samples were made. Results have shown that aluminium oxide surfaces with the same average roughness value (Ra) and mean roughness depth (Rz) typically used in the printing plate surface characterisation, have dramatically different surface <span class="hlt">topographies</span>. According to the type of instrument specific roughness parameters should be used for defining the printing plate surfaces. New surface roughness parameters were defined in order to insure detailed characterisation of the printing plates in graphic reproduction process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2741225','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2741225"><span id="translatedtitle">Enhanced surface hydrophobicity by coupling of surface polarity and <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Giovambattista, Nicolas; Debenedetti, Pablo G.; Rossky, Peter J.</p> <p>2009-01-01</p> <p>We use atomistic computer simulation to explore the relationship between mesoscopic (liquid drop contact angle) and microscopic (surface atomic polarity) characteristics for water in contact with a model solid surface based on the structure of silica. We vary both the magnitude and direction of the solid surface polarity at the atomic scale and characterize the response of an aqueous interface in terms of the solvent molecular organization and contact angle. We show that when the <span class="hlt">topography</span> and polarity of the surface act in concert with the asymmetric charge distribution of water, the hydrophobicity varies substantially and, further, can be maximal for a surface with significant polarity. The results suggest that patterning of a surface on several length scales, from atomic to ?m lengths, can make important independent contributions to macroscopic hydrophobicity. PMID:19706474</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3641517','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3641517"><span id="translatedtitle">Nicotine intake and smoking <span class="hlt">topography</span> in smokers with bipolar disorder</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Williams, Jill M; Gandhi, Kunal K; Lu, Shou-En; Steinberg, Marc L; Benowitz, Neal L</p> <p>2013-01-01</p> <p>Objectives Cigarette smoking behavior in bipolar disorder (BPD), including the effects of mood-stabilizing medications, has not been well characterized. Methods We compared serum nicotine, nicotine metabolite levels, and smoking <span class="hlt">topography</span> in 75 smokers with BPD to 86 control smokers (CON). For some comparisons, an additional control group of 75 smokers with schizophrenia (SCZ) were included. Results There were no differences between the BPD and CON groups in baseline smoking characteristics or serum nicotine or cotinine levels. Fifty-one smokers with BPD (68.9%) were taking one of the following mood stabilizers: valproic acid, lamotrigine, carbamazepine, oxcarbazepine, lithium, or topiramate. The 3-hydroxycotinine-to-cotinine ratio, a marker of cytochrome P450 2A6 (CYP2A6) metabolic activity, was significantly higher in BPD versus CON and versus SCZ (0.68 versus 0.49 versus 0.54; p = 0.002). The difference between groups, however, was no longer significant when the analysis was repeated with those taking hepatic enzyme-inducing drugs (carbamazepine, oxcarbazepine, and topiramate) included as a covariate. The time between puffs, or interpuff interval (IPI), was shorter in BPD versus CON by an average of 3.0 sec (p < 0.05), although this was no longer significant when we removed smokers from the analysis of those taking hepatic enzyme inducers. Conclusions Smokers with BPD are not different from CON on most measures of nicotine intake and smoking <span class="hlt">topography</span>. We found an increased rate of nicotine metabolism in smokers taking mood stabilizers that are hepatic enzyme inducers, including carbamazepine, oxcarbazepine, and topiramate. Smokers with rapid nicotine metabolism might be expected to smoke more intensely to compensate for the more rapid disappearance of nicotine from the blood and brain, and may have more difficulty in quitting smoking, although this requires further study. PMID:22938167</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMEP31B0811B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMEP31B0811B"><span id="translatedtitle">The Signature of Life in Stabilized Dune <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barchyn, T. E.; Hugenholtz, C.</p> <p>2012-12-01</p> <p>Life dramatically affects aeolian dunes on Earth by modifying dune morphology and immobilizing sediment. Complete immobilization (stabilization) occurs when vegetation growth shelters the surface and eliminates sediment transport (and the capacity of the dune to clear vegetation). In unidirectional dune forms stabilization is usually preceded by a period of transition dominated by pronounced morphological change (e.g., parabolic dunes). Here, we hypothesize that stabilized <span class="hlt">topography</span> holds previously unidentified clues detailing the kinematics and behavior of vegetation during stabilization (a 'signature'). During stabilization dune ridges advance downwind and 'bulldoze' vegetation in their path. We split dune ridges into a series of wind-parallel 'dune slices' and outline how slipface vegetation could prove to be a 'tipping point' in stabilization for each dune slice. Slipface vegetation sets off a self-reinforcing stabilization feedback, simplifying our treatment and yielding two predictable behaviors: slipfaces either clear vegetation (deposition rate > vegetation deposition tolerance), or succumb to vegetation and become immobilized (deposition rate < vegetation deposition tolerance). We model slipface deposition rates through slipface geometry and show how predictable variations in classical dune forms (i) could be responsible for incipient transformation of barchan to parabolic dunes, (ii) result in a progressive stabilization feedback fundamentally inconsistent with widely used dune activity indices, and (iii) record a quantitative signature of the relative kinematics of sediment flux and vegetation growth in stabilized slipface geometries. To explore the idea in real dune fields, we extract slipface deposition rates through slipface geometry recorded in digital terrain data for three dune fields: (i) Bigstick Sand Hills, SK, Canada, (ii) White Sands, NM, USA, and (iii) Cape Cod, MA, USA. With independent estimates of sediment flux and vegetation deposition tolerance we show how all three dune fields show consistent results with characteristic deposition rates approximately 60% of vegetation deposition tolerance. These results open the possibility that a consistent and identifiable 'signature of life' could be coded into all stabilized dune <span class="hlt">topography</span> worldwide.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.7688P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.7688P"><span id="translatedtitle">Relations between heat flow, <span class="hlt">topography</span> and Moho depth for Europe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Polkowski, Marcin; Majorowicz, Jacek; Grad, Marek</p> <p>2013-04-01</p> <p>The relation between heat flow, <span class="hlt">topography</span> and Moho depth for recent maps of Europe is presented. New heat flow map of Europe (Majorowicz and Wybraniec, 2010) is based on updated database of uncorrected heat flow values to which paleoclimatic correction is applied across the continental Europe. Correction is depth dependent due to a diffusive thermal transfer of the surface temperature forcing of which glacial-interglacial history has the largest impact. This explains some very low uncorrected heat flow values 20-30 mW/m2 in the shields, shallow basin areas of the cratons, and in other areas including orogenic belts were heat flow was likely underestimated. New integrated map of the European Moho depth (Grad et al., 2009) is the first high resolution digital map for European plate understand as an area from Ural Mountains in the east to mid-Atlantic ridge in the west, and Mediterranean Sea in the south to Spitsbergen and Barents Sea in Arctic in the north. For correlation we used: onshore heat flow density data with palaeoclimatic correction (5318 locations), <span class="hlt">topography</span> map (30 x 30 arc seconds; Danielson and Gesch, 2011) and Moho map (longitude, latitude and Moho depth, each 0.1 degree). Analysis was done in areas where data from all three datasets were available. Continental Europe area could be divided into two large domains related with Precambrian East European craton and Palaeozoic Platform. Next two smaller areas correspond to Scandinavian Caledonides and Anatolia. Presented results show different correlations between Moho depth, elevation and heat flow for all discussed regions. For each region more detailed analysis of these relation in different elevation ranges is presented. In general it is observed that Moho depth is more significant to HF then elevation. Depending on region and elevation range HF value in mW/m2 is up to two times larger than Moho depth in km, while HF relation to elevation varies much more.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70031552','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70031552"><span id="translatedtitle"><span class="hlt">Topography</span> and geomorphology of the Huygens landing site on Titan</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Soderblom, L.A.; Tomasko, M.G.; Archinal, B.A.; Becker, T.L.; Bushroe, M.W.; Cook, D.A.; Doose, L.R.; Galuszka, D.M.; Hare, T.M.; Howington-Kraus, E.; Karkoschka, E.; Kirk, R.L.; Lunine, J.I.; McFarlane, E.A.; Redding, B.L.; Rizk, B.; Rosiek, M.R.; See, C.; Smith, P.H.</p> <p>2007-01-01</p> <p>The Descent Imager/Spectral Radiometer (DISR) aboard the Huygens Probe took several hundred visible-light images with its three cameras on approach to the surface of Titan. Several sets of stereo image pairs were collected during the descent. The digital terrain models constructed from those images show rugged <span class="hlt">topography</span>, in places approaching the angle of repose, adjacent to flatter darker plains. Brighter regions north of the landing site display two styles of drainage patterns: (1) bright highlands with rough <span class="hlt">topography</span> and deeply incised branching dendritic drainage networks (up to fourth order) with dark-floored valleys that are suggestive of erosion by methane rainfall and (2) short, stubby low-order drainages that follow linear fault patterns forming canyon-like features suggestive of methane spring-sapping. The topographic data show that the bright highland terrains are extremely rugged; slopes of order of 30?? appear common. These systems drain into adjacent relatively flat, dark lowland terrains. A stereo model for part of the dark plains region to the east of the landing site suggests surface scour across this plain flowing from west to east leaving ???100-m-high bright ridges. Tectonic patterns are evident in (1) controlling the rectilinear, low-order, stubby drainages and (2) the "coastline" at the highland-lowland boundary with numerous straight and angular margins. In addition to flow from the highlands drainages, the lowland area shows evidence for more prolific flow parallel to the highland-lowland boundary leaving bright outliers resembling terrestrial sandbars. This implies major west to east floods across the plains where the probe landed with flow parallel to the highland-lowland boundary; the primary source of these flows is evidently not the dendritic channels in the bright highlands to the north. ?? 2007 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.chee.uh.edu/sites/chbe.egr.uh.edu/files/faculty/economou/jap_02_exp_molding.pdf','EPRINT'); return false;" href="http://www.chee.uh.edu/sites/chbe.egr.uh.edu/files/faculty/economou/jap_02_exp_molding.pdf"><span id="translatedtitle">Plasma molding over surface <span class="hlt">topography</span>: Energy and angular distribution of ions extracted out of large holes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Economou, Demetre J.</p> <p></p> <p>Plasma molding over surface <span class="hlt">topography</span>: Energy and angular distribution of ions extracted out November 2001 Plasma molding over surface <span class="hlt">topography</span> was investigated by measuring the energy and angular of plasma to mold around surfaces of com- plex shape finds application in coating of curved objects, etching</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://zabaras.com/Publications/PDFiles/MoldTopography.pdf','EPRINT'); return false;" href="http://zabaras.com/Publications/PDFiles/MoldTopography.pdf"><span id="translatedtitle">A thermomechanical study of the effects of mold <span class="hlt">topography</span> on the solidification of Aluminum alloys</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Zabaras, Nicholas J.</p> <p></p> <p>1 A thermomechanical study of the effects of mold <span class="hlt">topography</span> on the solidification of Aluminum-3801, USA A thermomechanical study of the effects of mold <span class="hlt">topography</span> on the solidification of Aluminum alloys at early times is provided. The various coupling mechanisms between the solid-shell and mold</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=mouse&pg=3&id=EJ792097','ERIC'); return false;" href="http://eric.ed.gov/?q=mouse&pg=3&id=EJ792097"><span id="translatedtitle"><span class="hlt">Topography</span> of Responses in Conditional Discrimination Influences Formation of Equivalence Classes</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kato, Olivia M.; de Rose, Julio C.; Faleiros, Pedro B.</p> <p>2008-01-01</p> <p>The effects of response <span class="hlt">topography</span> on stimulus class formation were studied in two experiments. In Experiment 1, 32 college students were assigned to 2 response <span class="hlt">topographies</span> and 2 stimulus sets, in a 2 x 2 design. Students selected stimuli by either moving a mouse to lace an arrow-shaped cursor on the stimulus or pressing a key corresponding to…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://topex.ucsd.edu/sandwell/publications/138.pdf','EPRINT'); return false;" href="http://topex.ucsd.edu/sandwell/publications/138.pdf"><span id="translatedtitle">Constraints on 3-D stress in the crust from support of mid-ocean ridge <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Sandwell, David T.</p> <p></p> <p>is the morphologic result of rifting, magmatism, and trans- form faulting associated with seafloor spreading driven of these stresses may be constrained using seafloor <span class="hlt">topography</span> and gravity. The <span class="hlt">topography</span> is divided into a short the slow spreading mid-Atlantic ridge, 40­50 MPa along the ultra­slow spreading ridges in the western</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.earthdynamics.org/papers-ED/2010/2010-Steinberger-etal-Icarus.pdf','EPRINT'); return false;" href="http://www.earthdynamics.org/papers-ED/2010/2010-Steinberger-etal-Icarus.pdf"><span id="translatedtitle">Deep versus shallow origin of gravity anomalies, <span class="hlt">topography</span> and volcanism on Earth, Venus and Mars</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Torsvik, Trond Helge</p> <p></p> <p>Deep versus shallow origin of gravity anomalies, <span class="hlt">topography</span> and volcanism on Earth, Venus and Mars Available online xxxx Keywords: Earth Venus, Interior Mars, Interior Volcanism a b s t r a c t The relation dynamics of planets. From the power spectra of gravity and <span class="hlt">topography</span> on Earth, Venus and Mars we infer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://geo.mff.cuni.cz/~oc/jgr06.pdf','EPRINT'); return false;" href="http://geo.mff.cuni.cz/~oc/jgr06.pdf"><span id="translatedtitle">Modeling the dynamic component of the geoid and <span class="hlt">topography</span> of Venus</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Cerveny, Vlastislav</p> <p></p> <p>Modeling the dynamic component of the geoid and <span class="hlt">topography</span> of Venus M. Pauer,1,2 K. Fleming,3 and O) the density structure of Venus' mantle can be approximated by a model in which the mass anomaly distribution of the geoid and <span class="hlt">topography</span> of Venus, J. Geophys. Res., 111, E11012, doi:10.1029/2005JE002511. 1. Introduction</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://perso.ens-lyon.fr/thierry.dauxois/PAPERS/pf21_121702.2009.pdf','EPRINT'); return false;" href="http://perso.ens-lyon.fr/thierry.dauxois/PAPERS/pf21_121702.2009.pdf"><span id="translatedtitle">A laboratory study of low-mode internal tide scattering by finite-amplitude <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Dauxois, Thierry</p> <p></p> <p>A laboratory study of low-mode internal tide scattering by finite-amplitude <span class="hlt">topography</span> Thomas concerning the scattering of a low-mode internal tide by finite-amplitude Gaussian <span class="hlt">topography</span>. Experiments produces significant reflection of the internal tide and transfer of energy from low to high modes. © 2009</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://tidesandcurrents.noaa.gov/publications/techrpt41.pdf','EPRINT'); return false;" href="http://tidesandcurrents.noaa.gov/publications/techrpt41.pdf"><span id="translatedtitle">NOAA Technical Report NOS CO-OPS 041 NORTH CAROLINA BATHYMETRY/<span class="hlt">TOPOGRAPHY</span> SEA LEVEL</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>NOAA Technical Report NOS CO-OPS 041 NORTH CAROLINA BATHYMETRY/<span class="hlt">TOPOGRAPHY</span> SEA LEVEL RISE PROJECT: DETERMINATION OF SEA LEVEL TRENDS Silver Spring, Maryland May 2004 noaa National Oceanic and Atmospheric Technical Report NOS CO-OPS 041 NORTH CAROLINA BATHYMETRY/<span class="hlt">TOPOGRAPHY</span> SEA LEVEL RISE PROJECT: DETERMINATION</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ipgp.fr/~wieczor/MyPapers/Neumann_et_al_2004.pdf','EPRINT'); return false;" href="http://www.ipgp.fr/~wieczor/MyPapers/Neumann_et_al_2004.pdf"><span id="translatedtitle">Crustal structure of Mars from gravity and <span class="hlt">topography</span> G. A. Neumann,1,2</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Wieczorek, Mark</p> <p></p> <p>Crustal structure of Mars from gravity and <span class="hlt">topography</span> G. A. Neumann,1,2 M. T. Zuber,1,2 M. A; accepted 11 June 2004; published 10 August 2004. [1] Mars Orbiter Laser Altimeter (MOLA) <span class="hlt">topography</span> and gravity models from 5 years of Mars Global Surveyor (MGS) spacecraft tracking provide a window</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OcSci..11..829Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OcSci..11..829Y"><span id="translatedtitle">Impacts of mean dynamic <span class="hlt">topography</span> on a regional ocean assimilation system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, C.; Zhu, J.; Tanajura, C. A. S.</p> <p>2015-10-01</p> <p>An ocean data assimilation system was developed for the Pacific-Indian oceans with the aim of assimilating altimetry data, sea surface temperature, and in situ measurements from Argo (Array for Real-time Geostrophic Oceanography), XBT (expendable bathythermographs), CTD (conductivity temperature depth), and TAO (Tropical Atmosphere Ocean). The altimetry data assimilation requires the addition of the mean dynamic <span class="hlt">topography</span> to the altimetric sea level anomaly to match the model sea surface height. The mean dynamic <span class="hlt">topography</span> is usually computed from the model long-term mean sea surface height, and is also available from gravimetric satellite data. In this study, the impact of different mean dynamic <span class="hlt">topographies</span> on the sea level anomaly assimilation is examined. Results show that impacts of the mean dynamic <span class="hlt">topography</span> cannot be neglected. The mean dynamic <span class="hlt">topography</span> from the model long-term mean sea surface height without assimilating in situ observations results in worsened subsurface temperature and salinity estimates. Even if all available observations including in situ measurements, sea surface temperature measurements, and altimetry data are assimilated, the estimates are still not improved. This proves the significant impact of the MDT (mean dynamic <span class="hlt">topography</span>) on the analysis system, as the other types of observations do not compensate for the shortcoming due to the altimetry data assimilation. The gravimeter-based mean dynamic <span class="hlt">topography</span> results in a good estimate compared with that of the experiment without assimilation. The mean dynamic <span class="hlt">topography</span> computed from the model long-term mean sea surface height after assimilating in situ observations presents better results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.usu.edu/geo/shervais/Shervais%20-%20My%20Articles/ShervaisHanan-Tectonics.pdf','EPRINT'); return false;" href="http://www.usu.edu/geo/shervais/Shervais%20-%20My%20Articles/ShervaisHanan-Tectonics.pdf"><span id="translatedtitle">Lithospheric <span class="hlt">topography</span>, tilted plumes, and the track of the Snake RiverYellowstone hot spot</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Shervais, John W.</p> <p></p> <p>Lithospheric <span class="hlt">topography</span>, tilted plumes, and the track of the Snake River­Yellowstone hot spot John; published 24 September 2008. [1] The trace of the Snake River­Yellowstone hot spot is the world's best), Lithospheric <span class="hlt">topography</span>, tilted plumes, and the track of the Snake River­Yellowstone hot spot, Tectonics, 27</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70013048','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70013048"><span id="translatedtitle">The role of erosion by fish in shaping <span class="hlt">topography</span> around Hudson submarine canyon.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Twichell, D.C.; Grimes, Craig B.; Jones, R. S.; Able, K.W.</p> <p>1985-01-01</p> <p>The close match of areas of rough <span class="hlt">topography</span> and high tilefish populations, the active burrowing of the sea floor, and the clustered distribution of the burrows suggest that the hummocky <span class="hlt">topography</span> in this area may be the result of continuous erosion by tilefish and associated crustaceans during the Holocene. -from Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S13A4420B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S13A4420B"><span id="translatedtitle">Effects of <span class="hlt">Topography</span> on Ground Motion in Southern California and the Wasatch Front Regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bielak, J.; Restrepo, D. L.; Taborda, R.</p> <p>2014-12-01</p> <p>We examine the effect of realistic surficial <span class="hlt">topography</span> by conducting a set of deterministic 3D ground motion numerical simulations in the Southern California, and the Wasatch Front regions. We incorporate the highly heterogeneous surficial <span class="hlt">topography</span> of both regions by implementing a Virtual <span class="hlt">Topography</span> scheme into Hercules, the octree-based finite-element earthquake simulator developed by the Quake Group at Carnegie Mellon University. We used ˜80×80×40 km3 volumes to perform fmax = 5 Hz simulations subjected to rupture sources representative of large earthquakes. Each region was simulated using three different models: (i) realistic 3D velocity structure with realistic <span class="hlt">topography</span> (CMP model); (ii) realistic 3D velocity structure without <span class="hlt">topography</span> (SQD model); and (iii) homogeneous half space with realistic <span class="hlt">topography</span> (HMG) model. Our results illustrate how realistic <span class="hlt">topography</span> greatly modifies the ground response. In particular, they highlight the importance of the combined interaction between source-effects, source-directivity, focusing, soft-soil conditions, and the 3D <span class="hlt">topography</span>. We provide quantitative evidence of this interaction by the inclusion of maps of topographic amplification factors between the CMP and the SQD models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....7987K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....7987K"><span id="translatedtitle">In need of combined <span class="hlt">topography</span> and bathymetry DEM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kisimoto, K.; Hilde, T.</p> <p>2003-04-01</p> <p>In many geoscience applications, digital elevation models (DEMs) are now more commonly used at different scales and greater resolution due to the great advancement in computer technology. Increasing the accuracy/resolution of the model and the coverage of the terrain (global model) has been the goal of users as mapping technology has improved and computers get faster and cheaper. The ETOPO5 (5 arc minutes spatial resolution land and seafloor model), initially developed in 1988 by Margo Edwards, then at Washington University, St. Louis, MO, has been the only global terrain model for a long time, and it is now being replaced by three new topographic and bathymetric DEMs, i.e.; the ETOPO2 (2 arc minutes spatial resolution land and seafloor model), the GTOPO30 land model with a spatial resolution of 30 arc seconds (c.a. 1km at equator) and the 'GEBCO 1-MINUTE GLOBAL BATHYMETRIC GRID' ocean floor model with a spatial resolution of 1 arc minute (c.a. 2 km at equator). These DEMs are products of projects through which compilation and reprocessing of existing and/or new datasets were made to meet user's new requirements. These ongoing efforts are valuable and support should be continued to refine and update these DEMs. On the other hand, a different approach to create a global bathymetric (seafloor) database exists. A method to estimate the seafloor <span class="hlt">topography</span> from satellite altimetry combined with existing ships' conventional sounding data was devised and a beautiful global seafloor database created and made public by W.H. Smith and D.T. Sandwell in 1997. The big advantage of this database is the uniformity of coverage, i.e. there is no large area where depths are missing. It has a spatial resolution of 2 arc minute. Another important effort is found in making regional, not global, seafloor databases with much finer resolutions in many countries. The Japan Hydrographic Department has compiled and released a 500m-grid <span class="hlt">topography</span> database around Japan, J-EGG500, in 1999. Although the coverage of this database is only a small portion of the Earth, the database has been highly appreciated in the academic community, and accepted in surprise by the general public when the database was displayed in 3D imagery to show its quality. This database could be rather smoothly combined with the finer land DEM of 250m spatial resolution (Japan250m.grd, K. Kisimoto, 2000). One of the most important applications of this combined DEM of <span class="hlt">topography</span> and bathymetry is tsunami modeling. Understanding of the coastal environment, management and development of the coastal region are other fields in need of these data. There is, however, an important issue to consider when we create a combined DEM of <span class="hlt">topography</span> and bathymetry in finer resolutions. The problem arises from the discrepancy of the standard datum planes or reference levels used for topographic leveling and bathymetric sounding. Land <span class="hlt">topography</span> (altitude) is defined by leveling from the single reference point determined by average mean sea level, in other words, land height is measured from the geoid. On the other hand, depth charts are made based on depth measured from locally determined reference sea surface level, and this value of sea surface level is taken from the long term average of the lowest tidal height. So, to create a combined DEM of <span class="hlt">topography</span> and bathymetry in very fine scale, we need to avoid this inconsistency between height and depth across the coastal region. Height and depth should be physically continuous relative to a single reference datum across the coast within such new high resolution DEMs. (N.B. Coast line is not equal to 'altitude-zero line' nor 'depth-zero line'. It is defined locally as the long term average of the highest tide level.) All of this said, we still need a lot of work on the ocean side. Global coverage with detailed bathymetric mapping is still poor. Seafloor imaging and other geophysical measurements/experiments should be organized and conducted internationally and interdisciplinary ways more than ever. We always need greater technological advancement</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940011842','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940011842"><span id="translatedtitle">An inversion of geoid and <span class="hlt">topography</span> for mantle and crustal structure on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kiefer, Walter; Bills, Bruce; Frey, Herb; Nerem, Steve; Roark, Jim; Zuber, Maria</p> <p>1993-01-01</p> <p>Mars has the largest amplitude geoid anomalies and surface <span class="hlt">topography</span> known on the terrestrial planets. A number of prior studies have analyzed Martian gravity anomalies and <span class="hlt">topography</span> in terms of isostasy and flexure of the crust and lithosphere. Other studies have emphasized the role of mantle convection in producing gravity anomalies and <span class="hlt">topography</span> in some regions of Mars. Geoid and <span class="hlt">topography</span> observations for simultaneous estimates of density anomalies in the crust and mantle of Mars are inverted. In performing this study, a recent degree 50 spherical harmonic expansion of the Martian gravity field (GMM-l) and a corresponding resolution expansion of the USGS Mars <span class="hlt">topography</span> model are used. However, our analysis is restricted to harmonic degrees up to L equals 25, which are better determined than the higher harmonics. This provides a half-wavelength horizontal resolution of 425 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JPhCS.311a2022M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JPhCS.311a2022M"><span id="translatedtitle">Surface <span class="hlt">topography</span> of cylindrical gear wheels after smoothing in abrasive mass, honing and shot peening</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Michalski, J.; Pawlus, P.; ?elasko, W.</p> <p>2011-08-01</p> <p>The present paper presents the analysis of surface <span class="hlt">topography</span> of gear teeth as the result of final machining processes. Teeth of multiple cylindrical gears shaped by grinding were smoothed in abrasive mass, honed or shot peened. The measurement of gears were made using coordinate measuring machine and 3D surface <span class="hlt">topography</span> stylus instrument. The following deviations were studied; pitch deviation, total pitches deviations, variation of teeth thickness and deviation of gear radial run-out. Changes in teeth surface <span class="hlt">topography</span> during machining process were determined. 3D surface <span class="hlt">topography</span> parameters, surface directionality as well as areal autocorrelation and power spectral density functions were taken into consideration. As the results of the analysis, the best surface <span class="hlt">topography</span> with regard to gear operational properties was recommended.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MeScT..26h5304X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MeScT..26h5304X"><span id="translatedtitle">Ultrasound imaging measurement of submerged <span class="hlt">topography</span> in the muddy water physical model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiao, Xiongwu; Guo, Bingxuan; Li, Deren; Zou, Xianjian; Zhang, Peng; liu, Jian-chen; Zang, Yu-fu</p> <p>2015-08-01</p> <p>The real-time, accurate measurement of submerged <span class="hlt">topography</span> is vital for the analysis of riverbed erosion and deposition. This paper describes a novel method of measuring submerged <span class="hlt">topography</span> in the B-scan image obtained using an ultrasound imaging device. Results show the distribution of gray values in the image has a process of mutation. This mutation process can be used to adaptively track the topographic lines between riverbed and water, based on the continuity of <span class="hlt">topography</span> in the horizontal direction. The extracted topographic lines, of one pixel width, are processed by a wavelet filtering method. Compared with the actual <span class="hlt">topography</span>, the measurement accuracy is within 1?mm. It is suitable for the real-time measurement and analysis of all current model <span class="hlt">topographies</span> with the advantage of good self-adaptation. In particular, it is visible and intuitive for muddy water in the movable-bed model experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6894878','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6894878"><span id="translatedtitle">Displacements and tilts from dip-slip faults and magma chambers beneath irregular surface <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>McTigue, D.F.; Segall, P.</p> <p>1988-06-01</p> <p>Surface displacements and tilts due to buried deformation sources are influenced by <span class="hlt">topography</span>. The leading-order corrections due to <span class="hlt">topography</span> of arbitrary profile, but small slope, are determined for dip-slip faults (edge dislocations) and magma bodies (lines of inflation) in a two-dimensional elastic medium. The vertical displacement correction is simply the product of the <span class="hlt">topography</span> and the horizontal normal strain due to the source in a flat half-space. The correction for a normal fault beneath an idealized basin-and-range <span class="hlt">topography</span> is a slight increase in the uplift on the range side. The effect of <span class="hlt">topography</span> for a line of inflation beneath a symmetric volcano is to reduce the central uplift. Failure to account for topographic influences can bias estimates of source depth and geometry. copyright American Geophysical Union 1988</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/62299','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/62299"><span id="translatedtitle">Radiation and Dissipation of Internal Waves Generated by Geostrophic Motions Impinging on Small-Scale <span class="hlt">Topography</span>: Theory</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Nikurashin, Maxim</p> <p></p> <p>Observations and inverse models suggest that small-scale turbulent mixing is enhanced in the Southern Ocean in regions above rough <span class="hlt">topography</span>. The enhancement extends O(1) km above the <span class="hlt">topography</span>, suggesting that mixing ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.cs.helsinki.fi/u/ahyvarin/papers/VR01.ps.gz','EPRINT'); return false;" href="http://www.cs.helsinki.fi/u/ahyvarin/papers/VR01.ps.gz"><span id="translatedtitle">A twolayer sparse coding model learns simple and complex cell receptive fields and <span class="hlt">topography</span> from natural images</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Hyvärinen, Aapo</p> <p></p> <p>A two­layer sparse coding model learns simple and complex cell receptive fields and <span class="hlt">topography</span> from principle of sparseness can also lead to emergence of <span class="hlt">topography</span> (columnar organization) and complex cell</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://zabaras.com/Publications/PDFiles/MSE05-Part2.pdf','EPRINT'); return false;" href="http://zabaras.com/Publications/PDFiles/MSE05-Part2.pdf"><span id="translatedtitle">A coupled thermomechanical, thermal transport and segregation analysis of the solidification of Aluminum alloys on molds of uneven <span class="hlt">topographies</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Zabaras, Nicholas J.</p> <p></p> <p>of Aluminum alloys on molds of uneven <span class="hlt">topographies</span> Deep Samantaa and Nicholas Zabarasa a Materials Process the mold-metal interface, are observed for different mold <span class="hlt">topographies</span> during the early stages in the melt, melt superheat and varying mold surface <span class="hlt">topography</span> on nucleation of air- gaps and evolution</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.chee.uh.edu/sites/chbe.egr.uh.edu/files/faculty/economou/ieee_plasma_molding_02.pdf','EPRINT'); return false;" href="http://www.chee.uh.edu/sites/chbe.egr.uh.edu/files/faculty/economou/ieee_plasma_molding_02.pdf"><span id="translatedtitle">2048 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 30, NO. 5, OCTOBER 2002 Plasma Molding Over Surface <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Economou, Demetre J.</p> <p></p> <p><span class="hlt">Topography</span>: Simulation of Ion Flow, and Energy and Angular Distributions Over Steps in RF High model was developed to study plasma "molding" over surface <span class="hlt">topography</span>. The radio frequency (RF) sheath <span class="hlt">topography</span>. The intermediate case is shown as L H [case (ii)]. the ion flux, IED, and ion angular</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.cs.colorado.edu/~cai/papers/jcp2011.pdf','EPRINT'); return false;" href="http://www.cs.colorado.edu/~cai/papers/jcp2011.pdf"><span id="translatedtitle">Parallel Multilevel Methods for Implicit Solution of Shallow Water Equations with Nonsmooth <span class="hlt">Topography</span> on the Cubed-sphere $</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Cai, Xiao-Chuan</p> <p></p> <p><span class="hlt">Topography</span> on the Cubed-sphere $ Chao Yanga,b , Xiao-Chuan Caia aDepartment of Computer Science, University for the case with nonsmooth <span class="hlt">topography</span> and the use of two- and three-level overlapping Schwarz methods and nonsmooth bottom <span class="hlt">topography</span>, and scales perfectly in terms of the strong scalability and reasonably well</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://web.mit.edu/raffaele/www/Publications_files/FerrariNikurashin10_1.pdf','EPRINT'); return false;" href="http://web.mit.edu/raffaele/www/Publications_files/FerrariNikurashin10_1.pdf"><span id="translatedtitle">Radiation and Dissipation of Internal Waves Generated by Geostrophic Motions Impinging on Small-Scale <span class="hlt">Topography</span>: Theory</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Ferrari, Raffaele</p> <p></p> <p>-Scale <span class="hlt">Topography</span>: Theory MAXIM NIKURASHIN Princeton University, Princeton, New Jersey RAFFAELE FERRARI mixing is enhanced in the Southern Ocean in regions above rough <span class="hlt">topography</span>. The enhancement extends O(1) km above the <span class="hlt">topography</span>, sug- gesting that mixing is supported by the breaking of gravity waves</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://geode.colorado.edu/~small/docs/2008WRR.pdf','EPRINT'); return false;" href="http://geode.colorado.edu/~small/docs/2008WRR.pdf"><span id="translatedtitle">Measurement of the connectivity of runoff source areas as determined by vegetation pattern and <span class="hlt">topography</span>: A tool</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Small, Eric</p> <p></p> <p>and <span class="hlt">topography</span>: A tool for assessing potential water and soil losses in drylands A´ ngeles G. Mayor,1 Susana source areas considering both vegetation pattern and <span class="hlt">topography</span>. Flowlength is calculated as the average and <span class="hlt">topography</span>: A tool for assessing potential water and soil losses in drylands, Water Resour. Res., 44, W10423</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ltl.iams.sinica.edu.tw/document/journal_paper/Opt_Lett_24_1732_99.pdf','EPRINT'); return false;" href="http://ltl.iams.sinica.edu.tw/document/journal_paper/Opt_Lett_24_1732_99.pdf"><span id="translatedtitle">1732 OPTICS LETTERS / Vol. 24, No. 23 / December 1, 1999 Deconvolution of local surface response from <span class="hlt">topography</span> in</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>from <span class="hlt">topography</span> in nanometer profilometry with a dual-scan method Chao-Wei Tsai, Chau-Hwang Lee of <span class="hlt">topography</span> and elasticity profiles. Similarly, in scanning tunneling microscopy (STM) the magnitude a simple yet accurate method for the deconvolution of <span class="hlt">topography</span> from lo- cal surface responses. We</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991SPIE.1492..176D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991SPIE.1492..176D"><span id="translatedtitle">Applications of laser ranging to ocean, ice, and land <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Degnan, John J.</p> <p>1991-09-01</p> <p>Satellite laser ranging (SLR) has been used for over two decades in the study of a variety of geophysical phenomena, including global tectonic plate motion, regional crustal deformation near plate boundaries, Earth''s gravity field, the orientation of its polar axis and rate of spin, lunar dynamics and general relativistic studies. The subcentimeter precision of the technique is now attracting the attention of a new community of scientists, notably those interested in high- resolution ocean, ice, and land <span class="hlt">topography</span>. Over the next several years, the international SLR network will provide an essential link between the geocentric terrestrial reference frame (as presently defined by the international VLBI and SLR networks) and two new oceanographic satellites, ERS-1 and TOPEX-Poseidon, which will range to sea and ice surfaces using microwave altimeters. The combined SLR/altimetry data set will provide precise orbits, improved gravity models, and estimates of the marine geoid. The latter are necessary to infer the dynamic sea surface <span class="hlt">topography</span> and will enable measurements of parameters important to an understanding of global change, such as mean sea level and ice sheet thickness. Laser tracking of oceanographic satellites from multiple sites as they overfly special calibration towers equipped with tide gauges will also provide periodic estimates of microwave altimeter bias. The few-centimeter precision orbits determined by the SLR network will be used as ''ground truth'' data in the intercomparison and performance evaluation of developmental space radio-navigation systems such as GPS (TOPEX/Poseidon) and PRARE (ERS-1). Future spaceborne two-color SLR instruments, such as NASA''s geoscience laser ranging system (GLRS), can monitor the tectonically-induced motions of tide gauges by bouncing laser pulses off of collocated retroreflectors. Similar systems can measure the barometric loading over the open ocean. When used as transmitters in spaceborne or airborne altimeters, the narrow beamwidths and short pulsewidths available from lasers can provide high spatial resolution (both horizontal and vertical) topographic data over land and ice in support of a diverse set of science applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006epsc.conf..619S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006epsc.conf..619S"><span id="translatedtitle">Kinetic model of dusty atmosphere around cometary nucleus with <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Skorov, Yu. V.; Keller, H. U.; Markelov, G. N.</p> <p></p> <p>The key to the explanation of most phenomena associated with the 'activity' of comets is the proper understanding of processes taking place within a thin layer around the nucleus/cometary atmosphere interface. As a comet is heated by the Sun, the highly variable dusty atmosphere is formed due to sublimation of volatile components of the cometary nucleus and lifting of nonvolatile grains. We believe that a cometary nucleus can be described as a body of high porosity and low density. The solar radiation can penetrate to a substantial skin depth. Thus both energy absorption and sublimation in the uppermost porous layer have a volumetric character. Due to intermolecular collisions in the innermost coma, backflows are formed. Therefore the nucleus and the innermost coma of an active comet constitute an interacting physical system. Our thermophysical model consists of a main block where the nonlinear nonstationary heat-conduction equation is solved and of three auxiliary blocks where the following are modeled: the absorption of the solar radiation; the transport of products of sublimation in the nonisothermal near-surface layer; and the backward gas flows caused by intermolecular collisions in the inner coma. The kinetic model of the near surface coma is treated by the Direct Simulation Monte Carlo (DSMC) model of dust-gas flows. Most of the time a cometary atmosphere is in a transitional and free-molecular regime and the kinetic approach is required to obtain a reliable solution. A modern implementation of DSMC and fast computers allow us to compute the gas flow in the near continuum regime. If the dust to gas mass ratio is low we can use an iterative approach consisting of the initialization, the pure gas flow computation, and the main procedure that includes tracking of dust grains in the gas flow. Tracking and computation of the gas flow is repeated until the solution converges. In high resolution pictures of a nuclei obtained by spacecraft, surface <span class="hlt">topography</span> is observed. Cometary nuclei show material inhomogeneity that also leads to significant variations of activity. Gas flows for realistic <span class="hlt">topography</span> (e.g. flat-bottom circular craters and mesas) as well as "spotty" surfaces are modeled. We show that the structure of the innermost coma depends on the nucleus shape and observe such phenomena as shock waves and jets. We conclude that dust grains mitigate gas flow discontinuities and that shock waves are less visible. Apart from that, dust grains effect gas density distribution: gas is being pushed away from dust jets and leaks into regions with a deficit of dust grains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000110441&hterms=Mystery&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMystery','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000110441&hterms=Mystery&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMystery"><span id="translatedtitle">The Mystery of the Mars North Polar Gravity-<span class="hlt">Topography</span> Correlation(Or Lack Thereof)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Phillips, R. J.; Sjogren, W. L.; Johnson, C. L.</p> <p>1999-01-01</p> <p>Maps of moderately high resolution gravity data obtained from the Mars Global Surveyor (MGS) gravity calibration orbit campaign and high precision <span class="hlt">topography</span> obtained from the Mars Orbiter Laser Altimeter (MOLA) experiment reveal relationships between gravity and <span class="hlt">topography</span> in high northern latitudes of Mars. Figure 1 shows the results of a JPL spherical harmonic gravity model bandpass filtered between degrees 6 and 50 contoured over a MOLA topographic image. A positive gravity anomaly exists over the main North Polar cap, but there are at least six additional positive gravity anomalies, as well as a number of smaller negative anomalies, with no obvious correlation to <span class="hlt">topography</span>. Additional information is contained in the original extended abstract.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPSC...10..514S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPSC...10..514S"><span id="translatedtitle">Estimation of Ganymede's <span class="hlt">Topography</span>, Rotation and Tidal Deformation - a Study of Synthetic Ganymede Laser Altimeter Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steinke, T.; Stark, A.; Steinbrügge, G.; Hussmann, H.; Oberst, J.</p> <p>2015-10-01</p> <p>We implement an iterative least-squares inversion routine to study the estimation of several dynamic Ganymede rotation parameters by laser altimetry. Based on spherical harmonic expansions of the global <span class="hlt">topography</span> we use simulated Ganymede Laser Al-timeter observations representing the synthetic <span class="hlt">topography</span> of the satellite. Besides the static <span class="hlt">topography</span> we determine the dynamical parameters, such as the rotation rate, the amplitudes of physical librations, the spin pole orientation, and the tidal deformation. This parameters may strengthen implications for a liquid ocean beneath Ganymede's icy shell and, in addition, constrain geodetic frame parameters essential for various space-borne experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006EOSTr..87..174G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006EOSTr..87..174G"><span id="translatedtitle">New Products From the Shuttle Radar <span class="hlt">Topography</span> Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gesch, Dean; Farr, Tom; Slater, James; Muller, Jan-Peter; Cook, Sally</p> <p>2006-05-01</p> <p>New data products with broad applicability to the Earth sciences are now available from the Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM). SRTM, a joint project of the National Geospatial-Intelligence Agency (NGA) and NASA, flew aboard the Space Shuttle Endeavour on an 11 day mission in February 2000 with the goal of collecting a near-global data set of high-resolution elevation data [Farr and Kobrick, 2000]. Data from the mission have been available to researchers for several years, but newly available products offer enhanced usability and applicability. Final products include elevation data resulting from a substantial editing effort by the NGA in which water bodies and coastlines were well defined and data artifacts known as spikes and wells (single pixel errors) were removed. This second version of the SRTM data set, also referred to as `finished' data, represents a significant improvement over earlier versions that had nonflat water bodies, poorly defined coastlines, and numerous noise artifacts. The edited data are available at a one-arc-second resolution (approximately 30 meters) for the United States and its territories, and at a three-arc-second resolution (approximately 90 meters) for non-U.S. areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4206323','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4206323"><span id="translatedtitle">OCT 3-D surface <span class="hlt">topography</span> of isolated human crystalline lenses</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sun, Mengchan; Birkenfeld, Judith; de Castro, Alberto; Ortiz, Sergio; Marcos, Susana</p> <p>2014-01-01</p> <p>Quantitative 3-D Optical Coherence Tomography was used to measure surface <span class="hlt">topography</span> of 36 isolated human lenses, and to evaluate the relationship between anterior and posterior lens surface shape and their changes with age. All lens surfaces were fitted to 6th order Zernike polynomials. Astigmatism was the predominant surface aberration in anterior and posterior lens surfaces (accounting for ~55% and ~63% of the variance respectively), followed by spherical terms, coma, trefoil and tetrafoil. The amount of anterior and posterior surface astigmatism did not vary significantly with age. The relative angle between anterior and posterior surface astigmatism axes was on average 36.5 deg, tended to decrease with age, and was >45 deg in 36.1% lenses. The anterior surface RMS spherical term, RMS coma and 3rd order RMS decreased significantly with age. In general, there was a statistically significant correlation between the 3rd and 4th order terms of the anterior and posterior surfaces. Understanding the coordination of anterior and posterior lens surface geometries and their topographical changes with age sheds light into the role of the lens in the optical properties of the eye and the lens aging mechanism. PMID:25360371</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140006611','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140006611"><span id="translatedtitle">Crater <span class="hlt">Topography</span> on Titan: Implications for Landscape Evolution</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Neish, Catherine D.; Kirk, R.L.; Lorenz, R. D.; Bray, V. J.; Schenk, P.; Stiles, B. W.; Turtle, E.; Mitchell, K.; Hayes, A.</p> <p>2013-01-01</p> <p>We present a comprehensive review of available crater <span class="hlt">topography</span> measurements for Saturn's moon Titan. In general, the depths of Titan's craters are within the range of depths observed for similarly sized fresh craters on Ganymede, but several hundreds of meters shallower than Ganymede's average depth vs. diameter trend. Depth-to-diameter ratios are between 0.0012 +/- 0.0003 (for the largest crater studied, Menrva, D approximately 425 km) and 0.017 +/- 0.004 (for the smallest crater studied, Ksa, D approximately 39 km). When we evaluate the Anderson-Darling goodness-of-fit parameter, we find that there is less than a 10% probability that Titan's craters have a current depth distribution that is consistent with the depth distribution of fresh craters on Ganymede. There is, however, a much higher probability that the relative depths are uniformly distributed between 0 (fresh) and 1 (completely infilled). This distribution is consistent with an infilling process that is relatively constant with time, such as aeolian deposition. Assuming that Ganymede represents a close 'airless' analogue to Titan, the difference in depths represents the first quantitative measure of the amount of modification that has shaped Titan's surface, the only body in the outer Solar System with extensive surface-atmosphere exchange.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060010995&hterms=longevity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dlongevity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060010995&hterms=longevity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dlongevity"><span id="translatedtitle">Extraction of Martian valley networks from digital <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stepinski, T. F.; Collier, M. L.</p> <p>2004-01-01</p> <p>We have developed a novel method for delineating valley networks on Mars. The valleys are inferred from digital <span class="hlt">topography</span> by an autonomous computer algorithm as drainage networks, instead of being manually mapped from images. Individual drainage basins are precisely defined and reconstructed to restore flow continuity disrupted by craters. Drainage networks are extracted from their underlying basins using the contributing area threshold method. We demonstrate that such drainage networks coincide with mapped valley networks verifying that valley networks are indeed drainage systems. Our procedure is capable of delineating and analyzing valley networks with unparalleled speed and consistency. We have applied this method to 28 Noachian locations on Mars exhibiting prominent valley networks. All extracted networks have a planar morphology similar to that of terrestrial river networks. They are characterized by a drainage density of approx.0.1/km, low in comparison to the drainage density of terrestrial river networks. Slopes of "streams" in Martian valley networks decrease downstream at a slower rate than slopes of streams in terrestrial river networks. This analysis, based on a sizable data set of valley networks, reveals that although valley networks have some features pointing to their origin by precipitation-fed runoff erosion, their quantitative characteristics suggest that precipitation intensity and/or longevity of past pluvial climate were inadequate to develop mature drainage basins on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFMOS32B0248B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFMOS32B0248B"><span id="translatedtitle">Airborne Sea-Surface <span class="hlt">Topography</span> in an Absolute Reference Frame</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brozena, J. M.; Childers, V. A.; Jacobs, G.; Blaha, J.</p> <p>2003-12-01</p> <p>Highly dynamic coastal ocean processes occur at temporal and spatial scales that cannot be captured by the present generation of satellite altimeters. Space-borne gravity missions such as GRACE also provide time-varying gravity and a geoidal msl reference surface at resolution that is too coarse for many coastal applications. The Naval Research Laboratory and the Naval Oceanographic Office have been testing the application of airborne measurement techniques, gravity and altimetry, to determine sea-surface height and height anomaly at the short scales required for littoral regions. We have developed a precise local gravimetric geoid over a test region in the northern Gulf of Mexico from historical gravity data and recent airborne gravity surveys. The local geoid provides a msl reference surface with a resolution of about 10-15 km and provides a means to connect airborne, satellite and tide-gage observations in an absolute (WGS-84) framework. A series of altimetry reflights over the region with time scales of 1 day to 1 year reveal a highly dynamic environment with coherent and rapidly varying sea-surface height anomalies. AXBT data collected at the same time show apparent correlation with wave-like temperature anomalies propagating up the continental slope of the Desoto Canyon. We present animations of the temporal evolution of the surface <span class="hlt">topography</span> and water column temperature structure down to the 800 m depth of the AXBT sensors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.sciencedirect.com/science/article/pii/S0019103509001456','USGSPUBS'); return false;" href="http://www.sciencedirect.com/science/article/pii/S0019103509001456"><span id="translatedtitle">Determining Titan surface <span class="hlt">topography</span> from Cassini SAR data</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stiles, Bryan W.; Hensley, Scott; Gim, Yonggyu; Bates, David M.; Kirk, Randolph L.; Hayes, Alex; Radebaugh, Jani; Lorenz, Ralph D.; Mitchell, Karl L.; Callahan, Philip S.; Zebker, Howard; Johnson, William T.K.; Wall, Stephen D.; Lunine, Jonathan I.; Wood, Charles A.; Janssen, Michael; Pelletier, Frederic; West, Richard D.; Veeramacheneni, Chandini</p> <p>2009-01-01</p> <p>A technique, referred to as SARTopo, has been developed for obtaining surface height estimates with 10 km horizontal resolution and 75 m vertical resolution of the surface of Titan along each Cassini Synthetic Aperture Radar (SAR) swath. We describe the technique and present maps of the co-located data sets. A global map and regional maps of Xanadu and the northern hemisphere hydrocarbon lakes district are included in the results. A strength of the technique is that it provides topographic information co-located with SAR imagery. Having a topographic context vastly improves the interpretability of the SAR imagery and is essential for understanding Titan. SARTopo is capable of estimating surface heights for most of the SAR-imaged surface of Titan. Currently nearly 30% of the surface is within 100 km of a SARTopo height profile. Other competing techniques provide orders of magnitude less coverage. We validate the SARTopo technique through comparison with known geomorphological features such as mountain ranges and craters, and by comparison with co-located nadir altimetry, including a 3000 km strip that had been observed by SAR a month earlier. In this area, the SARTopo and nadir altimetry data sets are co-located tightly (within 5-10 km for one 500 km section), have similar resolution, and as expected agree closely in surface height. Furthermore the region contains prominent high spatial resolution <span class="hlt">topography</span>, so it provides an excellent test of the resolution and precision of both techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.5403A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.5403A"><span id="translatedtitle">Dust as a potential tracer for the flow over <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alpert, Pinhas; Barkan, Yossi</p> <p>2015-04-01</p> <p>The distribution of mineral dust around topographical obstacles is examined, using the dimensionless Froude number (Fr) that describes different flow regimes in a fluid. Flow around a peak with a close-to-circular shape in dusty environment like the Sahara and the Sahel was examined in order to investigate the distribution of the dust around the obstacle in different flow regimes as expressed by the Fr number. The Total Ozone Mapping Spectrometer Aerosol Index (TOMS-AI) daily Aerosol Index, and the u and v wind components were used for the years 1979-1992, i.e. 14 years. It is first shown by the TOMS-AI data that the shape of the dust distribution around the circular peak is in good agreement with the shape of the peak itself. Additionally good correlation exists between the vertical distribution of the dust above the peak and the Froude Number in its vicinity. This method allows for the first time the investigation of flow above and around topographical obstacles in the open space employing dust as the flow-tracer. References: J. Barkan and P. Alpert, "Dust as a potential tracer for the flow over <span class="hlt">topography</span>", Intern. J. Geosci., (in press) 2015. J. Barkan and P. Alpert, "A unique case-study of near-circular Saharan dust transport over the Atlantic Ocean", Atmospheric and Climate Sciences (ACS), 4, 164-170, 2014.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003JPhD...36A..17B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JPhD...36A..17B"><span id="translatedtitle">A novel digital x-ray <span class="hlt">topography</span> system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bowen, D. K.; Wormington, M.; Feichtinger, P.</p> <p>2003-05-01</p> <p>X-ray <span class="hlt">topography</span> (XRT) is recognized as being a powerful tool for directly imaging defects in single crystals, semiconductor wafers and epitaxially grown layers. The timely identification of defects can lead to increased yields and significant cost savings in wafer processing. The primary limitation to its general usage within the semiconductor community has been the difficulty in system use and difficulty in integration into an in-line analytical tool. We have developed a novel, high-speed digital XRT method that can be implemented on a standard high-resolution x-ray diffraction (HRXRD) system equipped with a wafer translation stage and a microfocus tube (or a small aperture in front of a standard point source). It is also appropriate for an in-line fab tool with robot loading and automated operation. In this paper, we discuss the theory and present examples from work undertaken on a variety of materials, including: silicon, compound semiconductors and ionic crystals. Reflection and transmission methods are illustrated. Data were collected on a HRXRD system with a microfocus source and a CCD detector, and an innovative software integration and processing algorithm. Algorithms for full automation of the alignment, exposure and data collection processes have been worked out. It is estimated that the dedicated XRT tool now in prototype form will be capable of scanning a full 300 mm wafer in reflection in under two hours at 50 ?m resolution and one hour at 15 ?m resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Tecto..33..982W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Tecto..33..982W"><span id="translatedtitle">Accurate measurements of residual <span class="hlt">topography</span> from the oceanic realm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Winterbourne, Jeffrey; White, Nicky; Crosby, Alistair</p> <p>2014-06-01</p> <p>In the oceans, our understanding of plate subsidence as a function of age permits residual depth anomalies to be identified and mapped. These anomalies may reflect dynamic <span class="hlt">topography</span> and could be an important means for constraining convective circulation of the sublithospheric mantle. Here we analyze a global database of seismic reflection and wide-angle profiles from heavily sedimented oceanic crust, which abuts continental lithosphere. At 449 locations, we calculated water-loaded subsidence, compared it with a reference age-depth relationship, and determined residual depth. We then combined these spot measurements of residual depth with observations from mid-oceanic ridges and from selected ship track bathymetry to construct a global map of residual depth. Our results suggest that the amplitude of residual depth varies by up to ±1 km with wavelengths of order 103 km. We compare our residual depths with free-air gravity and seismic tomographic anomalies. Our results show that residual depths correlate with long-wavelength gravity anomalies. In contrast, correlations between residual depths and vertically averaged shear velocity anomalies within the upper and/or the lower mantle are weaker. The largest discrepancies occur at short (˜1000 km) wavelengths. These combined observations suggest that residual depth anomalies could be generate by density variations within a thin (˜102 km) low-viscosity layer beneath the lithosphere. Our global compilation should play a significant role in helping to refine predictive geodynamical models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4542339','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4542339"><span id="translatedtitle">Dynamic scalp <span class="hlt">topography</span> reveals neural signs just before performance errors</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ora, Hiroki; Sekiguchi, Tatsuhiko; Miyake, Yoshihiro</p> <p>2015-01-01</p> <p>Performance errors may cause serious consequences. It has been reported that ongoing activity of the frontal control regions across trials associates with the occurrence of performance errors. However, neural mechanisms that cause performance errors remain largely unknown. In this study, we hypothesized that some neural functions required for correct outcomes are lacking just before performance errors, and to determine this lack of neural function we applied a spatiotemporal analysis to high-density electroencephalogram signals recorded during a visual discrimination task, a d2 test of attention. To our knowledge, this is the first report of a difference in the temporal development of scalp ERP between trials with error, and correct outcomes as seen by <span class="hlt">topography</span> during the d2 test of attention. We observed differences in the signal potential in the frontal region and then the occipital region between reaction times matched with correct and error outcomes. Our observations suggest that lapses of top-down signals from frontal control regions cause performance errors just after the lapses. PMID:26289925</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARQ50011P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARQ50011P"><span id="translatedtitle">Renewable Interfaces: Surface <span class="hlt">Topography</span> Actuation for Complex Biological Adhesion Control</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pocivavsek, Luka; Ye, Sangho; Cao, Kathleen; Lee, Ka Yee C.; Velankar, Sachin; Wagner, William</p> <p>2015-03-01</p> <p>Controlling adhesion at biological interfaces is a complex problem with great biomedical importance. We use dynamic wrinkling, generated with PDMS/UVO chemistry under different macroscopic strains (?ij ~ 0 . 3), to create a mechanical interfacial term that frustrates particle adhesion. This device actuates surface <span class="hlt">topography</span> between flat (zero surface confinement ?ij) and wrinkled surfaces (?ij ~(A / ?) 2 , where A and ? are wrinkle amplitude and wavelength, respectively), with a maximum rate of 0.6 Hz. Un-actuated PDMS placed in contact with whole sheep blood shows near total surface coverage with adhered platelets over 90 min. Actuation showed a nearly 100-fold decrease in platelet adhesion. Interestingly, topographic actuation is four times as effective compared to flat surface actuation in controlling platelet adhesion. Our model explores the competition between surface tension terms (U? = ??ij) and interfacial elastic terms (U? =Eij (t .?ij2 +t3 . (?ij /?2)) generated because of actuation and wrinkling, where Eij is platelet modulus and t is characteristic platelet length scale. The condition for de-adhesion is U? >U? .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3077576','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3077576"><span id="translatedtitle">Nicotine metabolite ratio predicts smoking <span class="hlt">topography</span> and carcinogen biomarker level</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Strasser, Andrew A.; Benowitz, Neal L.; Pinto, Angela G.; Tang, Kathy Z.; Hecht, Stephen S.; Carmella, Steve G.; Tyndale, Rachel F.; Lerman, Caryn E.</p> <p>2010-01-01</p> <p>Background Variability in smoking behavior is partly attributable to heritable individual differences in nicotine clearance rates. This can be assessed as the ratio of the metabolites cotinine (COT) and 3'-hydroxycotinine (3HC) (referred to as the nicotine metabolism ratio, NMR). We hypothesized that faster NMR would be associated with greater cigarette puff volume and higher levels of total NNAL, a carcinogen biomarker. Methods Current smokers (n=109) smoked one of their preferred brand cigarettes through a smoking <span class="hlt">topography</span> device and provided specimens for NMR and total NNAL assays. Results Faster nicotine metabolizers (third and fourth quartiles versus first quartile) based on the NMR exhibited significantly greater total puff volume and total NNAL; the total puff volume by daily cigarette consumption interaction was a significant predictor of total NNAL level. Conclusion A heritable biomarker of nicotine clearance predicts total cigarette puff volume and total NNAL. Impact If validated, the NMR could contribute to smoking risk assessment in epidemiological studies and potentially in clinical practice. PMID:21212060</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JAG....86...88W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JAG....86...88W"><span id="translatedtitle">Numerical investigation of Rayleigh-wave propagation on <span class="hlt">topography</span> surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Limin; Luo, Yinhe; Xu, Yixian</p> <p>2012-11-01</p> <p>Rayleigh waves propagate along the free surface and vanish exponentially in the vertical direction, which suggests that they are strongly influenced by free-surface <span class="hlt">topography</span>. Since they have strong energy, Rayleigh waves are the most damaging wave during earthquake, and have strong noise in petroleum exploration. Because of their strong energy and the dispersive characteristic in a vertically inhomogeneous earth, however, they are widely utilized in environmental and engineering geophysics. To study how Rayleigh-wave behaves with topographic free surface, we proposed a finite difference scheme incorporating the acoustic/elastic interface approach into a 'stair-case' mesh for modeling surface-wave propagation. The effectiveness and accuracy were demonstrated by modeling results of a two-dimensional homogeneous half-space model with a slope free surface. The characteristics of Rayleigh-wave propagation strongly affected by topographic free surface are demonstrated by numerical examples of three simple topographic models. The most important revealed by modeling results is that, the dispersion characteristics are determined by the thicknesses of the underground layers in the direction perpendicular to the slope free surface. The middle of receiver-spread assumption was further verified, which provides a guideline to applying surface-wave methods to near-surface problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060010016&hterms=journal+physique&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Djournal%2Bphysique','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060010016&hterms=journal+physique&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Djournal%2Bphysique"><span id="translatedtitle">Crustal structure of Mars from gravity and <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Neumann, G. A.; Zuber, M. T.; Wieczorek, M. A.; McGovern, P. J.; Lemoine, F. G.; Smith, D. E.</p> <p>2004-01-01</p> <p>Mars Orbiter Laser Altimeter (MOLA) <span class="hlt">topography</span> and gravity models from 5 years of Mars Global Surveyor (MGS) spacecraft tracking provide a window into the structure of the Martian crust and upper mantle. We apply a finite-amplitude terrain correction assuming uniform crustal density and additional corrections for the anomalous densities of the polar caps, the major volcanos, and the hydrostatic flattening of the core. A nonlinear inversion for Moho relief yields a crustal thickness model that obeys a plausible power law and resolves features as small as 300 km wavelength. On the basis of petrological and geophysical constraints, we invoke a mantle density contrast of 600 kg m-3; with this assumption, the Isidis and Hellas gravity anomalies constrain the global mean crustal thickness to be >45 km. The crust is characterized by a degree 1 structure that is several times larger than any higher degree harmonic component, representing the geophysical manifestation of the planet's hemispheric dichotomy. It corresponds to a distinction between modal crustal thicknesses of 32 km and 58 km in the northern and southern hemispheres, respectively. The Tharsis rise and Hellas annulus represent the strongest components in the degree 2 crustal thickness structure. A uniform highland crustal thickness suggests a single mechanism for its formation, with subsequent modification by the Hellas impact, erosion, and the volcanic construction of Tharsis. The largest surviving lowland impact, Utopia, post-dated formation of the crustal dichotomy. Its crustal structure is preserved, making it unlikely that the northern crust was subsequently thinned by internal processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70043896','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70043896"><span id="translatedtitle">Crater <span class="hlt">topography</span> on Titan: implications for landscape evolution</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Neish, C.D.; Kirk, R.L.; Lorenz, R.D.; Bray, V.J.; Schenk, P.; Stiles, B.W.; Turtle, E.; Mitchell, Ken; Hayes, A.</p> <p>2013-01-01</p> <p>We present a comprehensive review of available crater <span class="hlt">topography</span> measurements for Saturn’s moon Titan. In general, the depths of Titan’s craters are within the range of depths observed for similarly sized fresh craters on Ganymede, but several hundreds of meters shallower than Ganymede’s average depth vs. diameter trend. Depth-to-diameter ratios are between 0.0012 ± 0.0003 (for the largest crater studied, Menrva, D ~ 425 km) and 0.017 ± 0.004 (for the smallest crater studied, Ksa, D ~ 39 km). When we evaluate the Anderson–Darling goodness-of-fit parameter, we find that there is less than a 10% probability that Titan’s craters have a current depth distribution that is consistent with the depth distribution of fresh craters on Ganymede. There is, however, a much higher probability that the relative depths are uniformly distributed between 0 (fresh) and 1 (completely infilled). This distribution is consistent with an infilling process that is relatively constant with time, such as aeolian deposition. Assuming that Ganymede represents a close ‘airless’ analogue to Titan, the difference in depths represents the first quantitative measure of the amount of modification that has shaped Titan’s surface, the only body in the outer Solar System with extensive surface–atmosphere exchange.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2224113','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2224113"><span id="translatedtitle"><span class="hlt">TOPOGRAPHY</span> OF THE ORGANIC COMPONENTS IN MOTHER-OF-PEARL</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Grégoire, Charles</p> <p>1957-01-01</p> <p>1. The <span class="hlt">topography</span> of the organic components (conchiolin) has been investigated on positive, postshadow-cast, formvar, and carbon replicas of mother-of-pearl from shells of a Cephalopod, of two Gastropods, and of six Pelecypods. All these shells are characterized by a true nacreous inner shell layer. 2. The material included normal shell surfaces, fragments of cleavage obtained by fracture, and surfaces polished tangentially and transversally to the inner surface of the shells. Replicas of these surfaces were prepared before and after etching of graded heaviness, induced by a chelating agent (sequestrene NA 2, titriplex III). Micrographs of the successive steps of the process of corrosion have been recorded. 3. Corrosion unmasked, on the nacreous surfaces, organic membranes or sheets, running as continuous formations in between adjacent mineral lamellae, and separating the individual crystals of aragonite which are aligned in rows and constitute each lamella. 4. The interlamellar sheets of material exhibit a reticulated structure, which is especially visible in preparations orientated tangentially to the lamellae and to the tabular surface of the aragonite crystals. The pattern of this lace-like structure, different in the various species studied, appeared in the same species as closely similar to that reported previously in leaflets of thoroughly decalcified mother-of-pearl, dissociated by ultrasonic waves. The present results support former conclusions with regard to the existence of taxonomic differences between Cephalopods, Gastropods, and Pelecypods in the morphological organization of the organic phase within mother-of-pearl. PMID:13475393</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMIN43A1501B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMIN43A1501B"><span id="translatedtitle">Display of Magellan SAR and <span class="hlt">Topography</span> Data in Google Earth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beyer, R. A.; Mehnert, E.; Sandwell, D. T.; Kolb, E.; Austin Foulkes, J.; Schwehr, K.; Johnson, C. L.</p> <p>2012-12-01</p> <p>Much of our understanding of the geodynamics and geology of Venus has been derived from radar imagery and <span class="hlt">topography</span> from the Magellan mission (NASA 1989-1994). These data were archived at the Planetary Data System (PDS) and are easily and freely available. Unfortunately, the Magellan Venus data are far less accessible than those of the Earth, Mars, and the Moon. Data for these bodies are available via the Google Earth geobrowser, allowing anyone to easily explore the latest imagery and surface information. In an effort to promote public interest in Venus, we have created content for Google Earth that displays three types of information from the Magellan-era. First the FMAP compilation of the Magellan SAR imagery has been assembled into a global overlay image for rapid panning and zooming. Second, the reprocessed altimetry data [Ford and Pettingell, 1992; Rappaport et al. 1999] have been carefully edited and merged with a global spherical harmonic analysis [Wieczorek, 2007] to form a 10-km resolution global DEM of the planet. Finally the IAU feature names along with the content from ``The Face of Venus'' [Roth and Wall, 1995] have been assembled as an overlay to provide basic naming and geology information. A draft version of this material is available by adding this Network Link in Google Earth: http://byss.arc.nasa.gov/ge-venus/venus.kml. We welcome comments and suggestions on how to best represent Venus data for the public</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19945746','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19945746"><span id="translatedtitle">The effect of <span class="hlt">topography</span> of polymer surfaces on platelet adhesion.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koh, Li Buay; Rodriguez, Isabel; Venkatraman, Subbu S</p> <p>2010-03-01</p> <p>In this study, the effect of surface <span class="hlt">topography</span> on fibrinogen and platelet adsorption was investigated. High aspect ratio surface features, in the submicron to nanometer range, were constructed on the poly- (lactic-co-glycolic-acid) (PLGA) films. The topographic surfaces were fabricated by solvent-mediated polymer casting on a master template. Fibrinogen adsorption and platelets adhesion on these topographic surfaces were quantified by enzyme linked immunosorbent assay (ELISA) and lactate dehydrogenase (LDH) assay respectively, while the activation of platelets was quantified by flow cytometric analysis using fluorescein isothiocyanate (FITC) tagging. The lowest fibrinogen adsorption amount and platelet activity was observed on surfaces with specific topographical features in the submicron range with a significant reduction in adhesion when compared to the pristine PLGA films. The topographical parameters found to induce low levels of fibrinogen adsorption and platelet response were high aspect ratio structures (>3:1) with reduced interspacing (<200 nm) or high density. The results signify that topographical manipulation of thrombogenic surfaces of biodegradable polymers is a feasible approach for reducing their thrombogenicity. PMID:19945746</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JBO....19a1006C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JBO....19a1006C"><span id="translatedtitle">Discriminant analysis of functional optical <span class="hlt">topography</span> for schizophrenia diagnosis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chuang, Ching-Cheng; Nakagome, Kazuyuki; Pu, Shenghong; Lan, Tsuo-Hung; Lee, Chia-Yen; Sun, Chia-Wei</p> <p>2014-01-01</p> <p>Abnormal prefrontal function plays a central role in the cognition deficits of schizophrenic patients; however, the character of the relationship between discriminant analysis and prefrontal activation remains undetermined. Recently, evidence of low prefrontal cortex (PFC) activation in individuals with schizophrenia has also been found during verbal fluency tests (VFT) and other cognitive tests with several neuroimaging methods. The purpose of this study is to assess the hemodynamic changes of the PFC and discriminant analysis between schizophrenia patients and healthy controls during VFT task by utilizing functional optical <span class="hlt">topography</span>. A total of 99 subjects including 53 schizophrenic patients and 46 age- and gender-matched healthy controls were studied. The results showed that the healthy group had larger activation in the right and left PFC than in the middle PFC. Besides, the schizophrenic group showed weaker task performance and lower activation in the whole PFC than the healthy group. The result of the discriminant analysis showed a significant difference with P value <0.001 in six channels (CH 23, 29, 31, 40, 42, 52) between the schizophrenic and healthy groups. Finally, 68.69% and 71.72% of subjects are correctly classified as being schizophrenic or healthy with all 52 channels and six significantly different channels, respectively. Our findings suggest that the left PFC can be a feature region for discriminant analysis of schizophrenic diagnosis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Icar..260..215J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Icar..260..215J"><span id="translatedtitle">Lithospheric structure of Venus from gravity and <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiménez-Díaz, Alberto; Ruiz, Javier; Kirby, Jon F.; Romeo, Ignacio; Tejero, Rosa; Capote, Ramón</p> <p>2015-11-01</p> <p>There are many fundamental and unanswered questions on the structure and evolution of the venusian lithosphere, which are key issues for understanding Venus in the context of the origin and evolution of the terrestrial planets. Here we investigate the lithospheric structure of Venus by calculating its crustal and effective elastic thicknesses (Tc and Te, respectively) from an analysis of gravity and <span class="hlt">topography</span>, in order to improve our knowledge of the large scale and long-term mechanical behaviour of its lithosphere. We find that the venusian crust is usually 20-25 km thick with thicker crust under the highlands. Our effective elastic thickness values range between 14 km (corresponding to the minimum resolvable Te value) and 94 km, but are dominated by low to moderate values. Te variations deduced from our model could represent regional variations in the cooling history of the lithosphere and/or mantle processes with limited surface manifestation. The crustal plateaus are near-isostatically compensated, consistent with a thin elastic lithosphere, showing a thickened crust beneath them, whereas the lowlands exhibit higher Te values, maybe indicating a cooler lithosphere than that when the venusian highlands were emplaced. The large volcanic rises show a complex signature, with a broad range of Te and internal load fraction (F) values. Finally, our results also reveal a significant contribution of the upper mantle to the strength of the lithosphere in many regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26172788','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26172788"><span id="translatedtitle">Anomalous sea surface structures as an object of statistical <span class="hlt">topography</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Klyatskin, V I; Koshel, K V</p> <p>2015-06-01</p> <p>By exploiting ideas of statistical <span class="hlt">topography</span>, we analyze the stochastic boundary problem of emergence of anomalous high structures on the sea surface. The kinematic boundary condition on the sea surface is assumed to be a closed stochastic quasilinear equation. Applying the stochastic Liouville equation, and presuming the stochastic nature of a given hydrodynamic velocity field within the diffusion approximation, we derive an equation for a spatially single-point, simultaneous joint probability density of the surface elevation field and its gradient. An important feature of the model is that it accounts for stochastic bottom irregularities as one, but not a single, perturbation. Hence, we address the assumption of the infinitely deep ocean to obtain statistic features of the surface elevation field and the squared elevation gradient field. According to the calculations, we show that clustering in the absolute surface elevation gradient field happens with the unit probability. It results in the emergence of rare events such as anomalous high structures and deep gaps on the sea surface almost in every realization of a stochastic velocity field. PMID:26172788</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100033697','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100033697"><span id="translatedtitle">STS-99 Shuttle Radar <span class="hlt">Topography</span> Mission Stability and Control</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hamelin, Jennifer L.; Jackson, Mark C.; Kirchwey, Christopher B.; Pileggi, Roberto A.</p> <p>2001-01-01</p> <p>The Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM) flew aboard Space Shuttle Endeavor February 2000 and used interferometry to map 80% of the Earth's landmass. SRTM employed a 200-foot deployable mast structure to extend a second antenna away from the main antenna located in the Shuttle payload bay. Mapping requirements demanded precision pointing and orbital trajectories from the Shuttle on-orbit Flight Control System (PCS). Mast structural dynamics interaction with the FCS impacted stability and performance of the autopilot for attitude maneuvers and pointing during mapping operations. A damper system added to ensure that mast tip motion remained with in the limits of the outboard antenna tracking system while mapping also helped to mitigate structural dynamic interaction with the FCS autopilot. Late changes made to the payload damper system, which actually failed on-orbit, required a redesign and verification of the FCS autopilot filtering schemes necessary to ensure rotational control stability. In-flight measurements using three sensors were used to validate models and gauge the accuracy and robustness of the pre-mission notch filter design.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990078398&hterms=Fahnestock&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DFahnestock','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990078398&hterms=Fahnestock&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DFahnestock"><span id="translatedtitle">Interferometric estimation of ice sheet motion and <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Joughlin, Ian; Kwok, Ron; Fahnestock, Mark; Winebrenner, Dale; Tulaczyk, Slawek; Gogenini, Prasad</p> <p>1997-01-01</p> <p>With ERS-1/2 satellite radar interferometry, it is possible to make measurements of glacier motion with high accuracy and fine spatial resolution. Interferometric techniques were applied to map velocity and <span class="hlt">topography</span> for several outlet glaciers in Greenland. For the Humboldt and Petermann glaciers, data from several adjacent tracks were combined to make a wide-area map that includes the enhanced flow regions of both glaciers. The discharge flux of the Petermann glacier upstream of the grounding line was estimated, thereby establishing the potential use of ERS-1/2 interferometric data for monitoring ice-sheet discharge. Interferograms collected along a single track are sensitive to only one component of motion. By utilizing data from ascending and descending passes and by making a surface-parallel flow assumption, it is possible to measure the full three-dimensional vector flow field. The application of this technique for an area on the Ryder glacier is demonstrated. Finally, ERS-1/2 interferograms were used to observe a mini-surge on the Ryder glacier that occurred in autumn of 1995.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3312788','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3312788"><span id="translatedtitle">Automated object-based classification of <span class="hlt">topography</span> from SRTM data</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dr?gu?, Lucian; Eisank, Clemens</p> <p>2012-01-01</p> <p>We introduce an object-based method to automatically classify <span class="hlt">topography</span> from SRTM data. The new method relies on the concept of decomposing land-surface complexity into more homogeneous domains. An elevation layer is automatically segmented and classified at three scale levels that represent domains of complexity by using self-adaptive, data-driven techniques. For each domain, scales in the data are detected with the help of local variance and segmentation is performed at these appropriate scales. Objects resulting from segmentation are partitioned into sub-domains based on thresholds given by the mean values of elevation and standard deviation of elevation respectively. Results resemble reasonably patterns of existing global and regional classifications, displaying a level of detail close to manually drawn maps. Statistical evaluation indicates that most of classes satisfy the regionalization requirements of maximizing internal homogeneity while minimizing external homogeneity. Most objects have boundaries matching natural discontinuities at regional level. The method is simple and fully automated. The input data consist of only one layer, which does not need any pre-processing. Both segmentation and classification rely on only two parameters: elevation and standard deviation of elevation. The methodology is implemented as a customized process for the eCognition® software, available as online download. The results are embedded in a web application with functionalities of visualization and download. PMID:22485060</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA11029&hterms=Phoenix+project&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPhoenix%2Bproject','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA11029&hterms=Phoenix+project&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPhoenix%2Bproject"><span id="translatedtitle">Wind-Related <span class="hlt">Topography</span> in Phoenix's Region of Mars (Animation)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2008-01-01</p> <p><p/> [figure removed for brevity, see original site] Click on image for animation <p/> This movie shifts from a global zoom indicating the Phoenix landing area on Mars to a topographical map indicating relative elevations in the landing region. The elevations could affect wind patterns at the site. <p/> In particular, Phoenix is in a broad, shallow valley. The edge of the valley, about 150 meters (500 feet) above the floor, may provide enough of a slope to the east of Phoenix to explain winds coming from the east during nights at the site. Cooler, denser air could be sinking down the slope and toward the lander. <p/> Atmospheric scientists on the Phoenix team are analyzing wind patterns to distiguish effects of nearby <span class="hlt">topography</span> from larger-scale movement of the atmosphere in the polar region. <p/> The elevation information for this topographical mapping comes from the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor orbiter. The blue-coded area is the valley floor. Orange and yellow indicate relatively higher elevations. <p/> The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver. JPL managed the Mars Global Surveyor mission for the NASA Science Mission Directorate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMED31A0743K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMED31A0743K"><span id="translatedtitle">Leveraging High Resolution <span class="hlt">Topography</span> for Education and Outreach: Updates to Open<span class="hlt">Topography</span> to make EarthScope and Other Lidar Datasets more Prominent in Geoscience Education</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kleber, E.; Crosby, C. J.; Arrowsmith, R.; Robinson, S.; Haddad, D. E.</p> <p>2013-12-01</p> <p>The use of Light Detection and Ranging (lidar) derived <span class="hlt">topography</span> has become an indispensable tool in Earth science research. The collection of high-resolution lidar <span class="hlt">topography</span> from an airborne or terrestrial platform allows landscapes and landforms to be represented at sub-meter resolution and in three dimensions. In addition to its high value for scientific research, lidar derived <span class="hlt">topography</span> has tremendous potential as a tool for Earth science education. Recent science education initiatives and a community call for access to research-level data make the time ripe to expose lidar data and derived data products as a teaching tool. High resolution topographic data fosters several Disciplinary Core Ideas (DCIs) of the Next Generation Science Standards (NGS, 2013), presents respective Big Ideas of the new community-driven Earth Science Literacy Initiative (ESLI, 2009), teaches to a number National Science Education Standards (NSES, 1996), and Benchmarks for Science Literacy (AAAS, 1993) for science education for undergraduate physical and environmental earth science classes. The spatial context of lidar data complements concepts like visualization, place-based learning, inquiry based teaching and active learning essential to teaching in the geosciences. As official host to EarthScope lidar datasets for tectonically active areas in the western United States, the NSF-funded Open<span class="hlt">Topography</span> facility provides user-friendly access to a wealth of data that is easily incorporated into Earth science educational materials. Open<span class="hlt">Topography</span> (www.opentopography.org), in collaboration with EarthScope, has developed education and outreach activities to foster teacher, student and researcher utilization of lidar data. These educational resources use lidar data coupled with free tools such as Google Earth to provide a means for students and the interested public to visualize and explore Earth's surface in an interactive manner not possible with most other remotely sensed imagery. The education section of the Open<span class="hlt">Topography</span> portal has recently been strengthened with the addition of several new resources and the re-organization of existing content for easy discovery. New resources include a detailed frequently asked questions (FAQ) section, updated 'How-to' videos for downloading data from Open<span class="hlt">Topography</span> and additional webpages aimed at students, educators and researchers leveraging existing and updated resources from Open<span class="hlt">Topography</span>, EarthScope and other organizations. In addition, the OpenLandform catalog, an online collection of classic geologic landforms depicted in lidar, has been updated to include additional tectonic landforms from EarthScope lidar datasets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000081438&hterms=Basalt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DBasalt','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000081438&hterms=Basalt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DBasalt"><span id="translatedtitle">Emplacement of Long Lava Flows: Detailed <span class="hlt">Topography</span> of the Carrizozo Basalt Lava Flow, New Mexico</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zimbelman, J. R; Johnston, A. K.</p> <p>2000-01-01</p> <p>The Carrizozo flow in south-central New Mexico was examined to obtain detailed <span class="hlt">topography</span> for a long basaltic lava flow. This information will be helpful in evaluating emplacement models for long lava flows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=207463','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=207463"><span id="translatedtitle">Modeling surface winds in mountainous catchments as a function of <span class="hlt">topography</span> and vegetation</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>In order to develop accurate distributed hydrological models, spatially accurate meteorological forcing fields are required. In mountainous basins, elevation and <span class="hlt">topography</span> strongly influence temperature, precipitation, vapor pressure, and wind. At the watershed scale, temperature, precipitation, ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/96954','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/96954"><span id="translatedtitle">The Impact of Finite-Amplitude Bottom <span class="hlt">Topography</span> on Internal Wave Generation in the Southern Ocean</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Nikurashin, Maxim</p> <p></p> <p>Direct observations in the Southern Ocean report enhanced internal wave activity and turbulence in a kilometer-thick layer above rough bottom <span class="hlt">topography</span> collocated with the deep-reaching fronts of the Antarctic Circumpolar ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.fs.fed.us/psw/publications/documents/psw_gtr184/psw_gtr184_005_HarrisNorm.pdf','EPRINT'); return false;" href="http://www.fs.fed.us/psw/publications/documents/psw_gtr184/psw_gtr184_005_HarrisNorm.pdf"><span id="translatedtitle">The Effect of <span class="hlt">Topography</span>, Vegetation, and Weather on Cattle Distribution at the San</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>The Effect of <span class="hlt">Topography</span>, Vegetation, and Weather on Cattle Distribution at the San Joaquin were implemented to judge the effects of these management techniques on cattle distribution. Animal period. Our study identified topographic, vegetative and environmental forces that affected cattle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://kuscholarworks.ku.edu/handle/1808/17298','EPRINT'); return false;" href="http://kuscholarworks.ku.edu/handle/1808/17298"><span id="translatedtitle">Subglacial <span class="hlt">topography</span> and geothermal heat flux: potential interactions with drainage of the Greenland ice sheet</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>van der Veen, Cornelis J.; Leftwich, T.; von Frese, R.; Csatho, B. M.; Li, J.</p> <p>2007-06-05</p> <p>[1] Many of the outlet glaciers in Greenland overlie deep and narrow trenches cut into the bedrock. It is well known that pronounced <span class="hlt">topography</span> intensifies the geothermal heat flux in deep valleys and attenuates this flux on mountains. Here we...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/30048','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/30048"><span id="translatedtitle"><span class="hlt">Topography</span> effects in the 1999 Athens earthquake : engineering issues in seismology</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Assimaki, Dominic, 1975-</p> <p>2004-01-01</p> <p>It is well known that irregular <span class="hlt">topography</span> can substantially affect the amplitude and frequency characteristics of seismic motion. Macroseismic observations of destructive earthquakes often show higher damage intensity at ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://web.stanford.edu/group/denny/Publications/ODonnell_Denny_wave_forces_surface_topography_LNO_2008.pdf','EPRINT'); return false;" href="http://web.stanford.edu/group/denny/Publications/ODonnell_Denny_wave_forces_surface_topography_LNO_2008.pdf"><span id="translatedtitle">Hydrodynamic forces and surface <span class="hlt">topography</span>: Centimeter-scale spatial variation in wave forces</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Denny, Mark</p> <p></p> <p>that protection from hydrodynamic forces is not a certain consequence of a rugose substratum, suggesting. On the rugose rock surfaces of wave-swept shores, interactions between substratum <span class="hlt">topography</span> and wave</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070018234&hterms=itokawa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D20%26Ntt%3Ditokawa','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070018234&hterms=itokawa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D20%26Ntt%3Ditokawa"><span id="translatedtitle">High Resolution Global <span class="hlt">Topography</span> of Itokawa from Hayabusa Imaging and LIDAR Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gaskell, Robert W.; Barnouin-Jha, O. S.; Scheeres, D. J.; Mukai, T.; Hirata, N.; Abe, S.; Saito, J.; Hashimoto, T.; Ishiguro, M.; Kubota, T.</p> <p>2006-01-01</p> <p>This viewgraph document reviews the <span class="hlt">topography</span> of the Itokawa asteroid. It summarizes some of the relevant information about the asteroid, and how using the imaging from Hayabusa and LIDAR data, a topographic image of Itokawa was derived.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/62004','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/62004"><span id="translatedtitle">A laboratory study of low-mode internal tide scattering by finite-amplitude <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Peacock, Thomas</p> <p></p> <p>We present the first laboratory experimental results concerning the scattering of a low-mode internal tide by finite-amplitude Gaussian <span class="hlt">topography</span>. Experiments performed at the Coriolis Platform in Grenoble used a recently ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/36242','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/36242"><span id="translatedtitle">Experimental investigation of internal tide generation by two-dimensional <span class="hlt">topography</span> using synthetic Schlieren</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Echeverri Mondragón, Paula</p> <p>2006-01-01</p> <p>An experimental investigation of internal tide generation at two-dimensional <span class="hlt">topography</span> was carried out using the synthetic Schlieren experimental technique. Two linear models were tested: Balmforth, Ierley and Young's [1] ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRE..118..908B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRE..118..908B"><span id="translatedtitle">Convection-driven compaction as a possible origin of Enceladus's long wavelength <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Besserer, J.; Nimmo, F.; Roberts, J. H.; Pappalardo, R. T.</p> <p>2013-05-01</p> <p>The long wavelength surface <span class="hlt">topography</span> of Enceladus shows depressions about 1 km in depth and ˜102 km wide. One possible cause of this <span class="hlt">topography</span> is spatially variable amounts of compaction of an initially porous ice shell, driven by spatial variations in heat flux. Here, we show that the heat flux variations associated with convection in the shell can quantitatively match the observed features. We develop a simple model of viscous compaction that includes the effect of porosity on thermal conductivity, and find that an initial shell porosity of at least 20-25% is required to develop the observed <span class="hlt">topography</span> over ˜1 Ga. This mechanism produces topographic depressions, not rises, above convective upwellings, and does not generate detectable gravity anomalies. Unlike transient dynamic <span class="hlt">topography</span>, it can potentially leave a permanent record of ancient convective processes in the shallow lithospheres of icy satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://oaktrust.library.tamu.edu//handle/1969.1/ETD-TAMU-1993-THESIS-A316','EPRINT'); return false;" href="http://oaktrust.library.tamu.edu//handle/1969.1/ETD-TAMU-1993-THESIS-A316"><span id="translatedtitle">The effect of <span class="hlt">topography</span> on the wavelet response of seismic arrays </span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Al-Shuhail, Abdullatif Abdulrahman</p> <p>1993-01-01</p> <p>Analyzing seismic arrays using their responses to wavelets provides a more convenient and direct method of analysis than using their conventional time-harmonic responses. In this study, the effect of <span class="hlt">topography</span> on the wavelet response of seismic...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAG...116...93W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAG...116...93W"><span id="translatedtitle">Effect of near-surface <span class="hlt">topography</span> on high-frequency Rayleigh-wave propagation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Limin; Xu, Yixian; Xia, Jianghai; Luo, Yinhe</p> <p>2015-05-01</p> <p>Rayleigh waves, which are formed due to interference of P- and Sv-waves near the free surface, propagate along the free surface and vanish exponentially in the vertical direction. Their propagation is strongly influenced by surface <span class="hlt">topography</span>. Due to the high resolution and precision requirements of near-surface investigations, the high-frequency Rayleigh waves are usually used for near-surface structural detecting. Although there are some numerical studies on high-frequency Rayleigh-wave propagation on topographic free surface, detailed analysis of characters of high-frequency Rayleigh-wave propagation on topographic free surface remains untouched. Hence, research of propagation of Rayleigh waves on complex topographic surface becomes critical for Rayleigh-wave methods in near-surface applications. To study the propagation of high-frequency Rayleigh waves on topographic free surface, two main topographic models are designed in this study. One of the models contains a depressed topographic surface, and another contains an uplifted topographic surface. We numerically simulate the propagation of high-frequency Rayleigh waves on these two topographic surfaces by finite-difference method. Soon afterwards, we analyze the propagation character of high-frequency Rayleigh waves on such topographic models, and compare the variations on its energy and frequency before and after passing the topographic region. At last, we discuss the relationship between the variations and topographical steepness of each model. Our numerical results indicate that influence of depressed <span class="hlt">topography</span> for high-frequency Rayleigh waves is more distinct than influence of uplifted <span class="hlt">topography</span>. Rayleigh waves produce new scattering body waves during passing the depressed <span class="hlt">topography</span> with reduction of amplitude and loss of high-frequency components. Moreover, the steeper the depressed <span class="hlt">topography</span> is, the more energy of Rayleigh waves is lost. The uplifted <span class="hlt">topography</span> with gentle slope produces similar influence as the depressed <span class="hlt">topography</span> on propagation of high-frequency Rayleigh waves. When slopes are getting steep, however, the obstacle influence of the uplifted <span class="hlt">topography</span> becomes weak. In addition, in the uplifted-<span class="hlt">topography</span> case, part of Rayleigh-wave energy is absorbed by the uplifted terrain, which includes the trapped energy between the uplifted boundaries and the generation of scattering waves. Meanwhile, local <span class="hlt">topography</span> strongly affects the character of Rayleigh-wave dispersion. Egregious error may be introduced, when pick Rayleigh-wave phase velocities on dispersion energy images for an MASW survey, if the local free-surface <span class="hlt">topography</span> is ignored.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.P22B..05D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.P22B..05D"><span id="translatedtitle">Modeling Floods in Athabasca Valles, Mars, Using CTX Stereo <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dundas, C. M.; Keszthelyi, L. P.; Denlinger, R. P.; Thomas, O. H.; Galuszka, D.; Hare, T. M.; Kirk, R. L.; Howington-Kraus, E.; Rosiek, M.</p> <p>2012-12-01</p> <p>Among the most remarkable landforms on Mars are the outflow channels, which suggest the occurrence of catastrophic water floods in the past. Athabasca Valles has long been thought to be the youngest of these channels [1-2], although it has recently become clear that the young crater age applies to a coating lava flow [3]. Simulations with a 2.5-dimensional flood model have provided insight into the details of flood dynamics but have also demonstrated that the Digital Elevation Model (DEM) from the Mars Orbiter Laser Altimeter (MOLA) Mission Experiment Gridded Data Records includes significant artifacts at this latitude at the scales relevant for flood modeling [4]. In order to obtain improved <span class="hlt">topography</span>, we processed stereo images from the Context Camera (CTX) of the Mars Reconnaissance Orbiter (MRO) using methods developed for producing topographic models of the Moon with images from the Lunar Reconnaissance Orbiter Camera, a derivative of the CTX camera. Some work on flood modeling with CTX stereo has been published by [5], but we will present several advances, including corrections to the published CTX optical distortion model and improved methods to combine the stereo and MOLA data. The limitations of current methods are the accuracy of control to MOLA and the level of error introduced when the MRO spacecraft is not in a high-stability mode during stereo imaging, leading to jitter impacting the derived <span class="hlt">topography</span>. Construction of a mosaic of multiple stereo pairs, controlled to MOLA, allows us to consider flow through the cluster of streamlined islands in the upper part of the channel [6], including what is suggested to be the best example of flood-formed subaqueous dunes on Mars [7]. We will present results from running a flood model [4, 8] through the high-resolution (100 m/post) DEM covering the streamlined islands and subaqueous dunes, using results from a lower-resolution model as a guide to the inflow. By considering a range of flow levels below estimated peak flow, we can examine the flow behavior at the site of the apparent subaqueous dunes and, in particular, assess whether the flow in this area is uniquely conducive to the formation of such bedforms [e.g., 9]. [1] Berman D. C. and Hartmann W. K. (2002) Icarus 159, 1-17. [2] Burr D. M. et al. (2002) Icarus 159, 53-73. [3] Jaeger W. L. et al. (2010) Icarus 205, 230-243. [4] Keszthelyi L. P. et al. (2007) GRL 34, L21206. [5] McIntyre et al. (2012) JGR 117, E03009. [6] Burr D. (2005) Geomorphology 69, 242-252. [7] Burr D. M. et al. (2004) Icarus 171, 68-83. [8] Denlinger R. P. and O'Connell D. R. H. (2008) J. Hyd. Eng. 134, 1590-1602. [9] Kleinhans M. G. (2005) JGR 110, E12003.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.T43B2661Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.T43B2661Q"><span id="translatedtitle">The origin of the Iberian microplate high <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quintana, L.; Pulgar, J. A.; Alonso, J. L.; Fernandez Viejo, G.</p> <p>2013-12-01</p> <p>The Iberian microplate is about 1100 km width, 3500 km long, and experienced contraction during the Cenozoic convergence of the Eurasian and African plates. In this process two main mountain ranges were created in the boundaries of the microplate: the Cantabrian-Pyrenean range in the north and the Betic-Rif orogenic system in the south, with a maximun height of 3479 m over sea level. However, in the interior of the microplate there is also several ranges and plateaus, with maximun heights of 2592 m. The origin of these interior high <span class="hlt">topography</span> is controversial and has been explained by means of several procesess as: a) transference of displacement from the south border of the microplate, b) lithospheric folding, or c) more complex deep mantle related processes. In this work we investigate the relation between the northern border range of the microplate and some Iberian interior reliefs as: a) the Spanish Central System range, located in the central part of the microplate, with peaks over 2500 m, and b) the North-Iberian meseta, situated between these two ranges, and with average heights of 750 m. In order to solve this relation we have built a crustal-scale cross-section, through the northern half of the Iberian microplate, by using field geological mapping, subsoil information and deep geophysical data. The section acroos the central part of the Cantabrian range shows the well-known Iberian microplate continental subduction beneath the Eurasian plate, with a prominent crustal root that reaches up to 45 km depth. In this section an important difference between the upper and lower crust shortening values has been found. Thus, the upper crust has been shortened 97 km while the lower crust 122 km. The section across de Central System range shows a slightly thickened crust. In this range also exist a difference in the shortening values between upper and lower crust, but in the contrary sense than the Cantabrian range. Thus, the Central System range has been shortened between 24-50 km in the upper crust, while the lower crust shows minor shortening. To solve this controversy, we propose that the Cantabrian and the Central System ranges are connected through a middle crustal detachment, 300 km long, beneath the North-Iberian meseta. Thus the default of shortening of the Central System lower crust is balanced by the excess of shortening of the Cantabrian lower crust subduction. At the same time we propose that the middle crustal detachment is not horizonal but rather a very low angle ramp dipping to the north. With this geometry we explain also the uplift of the North-Iberian meseta.We conclude that the mechanism that best explain the origin of the Iberian microplate interior high <span class="hlt">topography</span> is the transference of displacement from the border ranges to the interior ones of the microplate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/980232','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/980232"><span id="translatedtitle">High Resolution <span class="hlt">Topography</span> Analysis on Threading Edge Dislocations in 4H-SiC Epilayers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kamata, I.; Nagano, M; Tsuchida, H; Chen, Y; Dudley, M</p> <p>2009-01-01</p> <p>Threading edge dislocations (TEDs) in a 4H-SiC epitaxial layer are investigated using high-resolution synchrotron <span class="hlt">topography</span>. Six types of TED image are confirmed to correspond to the Burgers vector directions by a comparison of computer simulated images and observed <span class="hlt">topography</span> images in crystal boundaries. Using a mapping method, a wide spatial distribution of the six types of TED is examined in a quarter section of a 2-inch wafer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SuTMP...2b5004P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SuTMP...2b5004P"><span id="translatedtitle">The effect of selected parameters of the honing process on cylinder liner surface <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pawlus, P.; Dzierwa, A.; Michalski, J.; Reizer, R.; Wieczorowski, M.; Majchrowski, R.</p> <p>2014-04-01</p> <p>Many truck cylinder liners made from gray cast iron were machined. Ceramic and diamond honing stones were used in the last stages of operation: coarse honing and plateau honing. The effect of honing parameters on the cylinder liner surface <span class="hlt">topography</span> was studied. Selected surface <span class="hlt">topography</span> parameters were response variables. It was found that parameters from the Sq group were sensitive to honing parameter change. When plateau honing time varied, the Smq parameter increased, while the other parameters, Spq and Svq, were stable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23613185','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23613185"><span id="translatedtitle">Mechanical forces regulate stem cell response to surface <span class="hlt">topography</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saldaña, Laura; Crespo, Lara; Bensiamar, Fátima; Arruebo, Manuel; Vilaboa, Nuria</p> <p>2014-01-01</p> <p>The interactions between bone tissue and orthopedic implants are strongly affected by mechanical forces at the bone-implant interface, but the interplay between surface <span class="hlt">topographies</span>, mechanical stimuli, and cell behavior is complex and not well understood yet. This study reports on the influence of mechanical stretch on human mesenchymal stem cells (hMSCs) attached to metallic substrates with different roughness. Controlled forces were applied to plasma membrane of hMSCs cultured on smooth and rough stainless steel surfaces using magnetic collagen-coated particles and an electromagnet system. Degree of phosphorylation of focal adhesion kinase (p-FAK) on the active form (Tyr-397), prostaglandin E2 (PGE2) and vascular endothelial growth factor (VEGF) levels increased on rough samples under static conditions. Cell viability and fibronectin production decreased on rough substrates, while hMSCs maturated to the osteoblastic lineage to a similar extent on both surfaces. PGE2 production and osteoprotegerin/receptor activator of nuclear factor kappa-B ligand ratio increased after force application on both surfaces, although to a greater extent on smooth substrates. p-FAK on Tyr-397 was induced fairly rapidly by mechanical stimulation on rough surfaces while cells cultured on smooth samples failed to activate this kinase in response to tensile forces. Mechanical forces enhanced VEGF secretion and reduced cell viability, fibronetin levels and osteoblastic maturation on smooth surfaces but not on rough samples. The magnetite beads model used in this study is well suited to characterize the response of hMSCs cultured on metallic surfaces to tensile forces and collected data suggest a mechanism whereby mechanotransduction driven by FAK is essential for stem cell growth and functioning on metallic substrates. PMID:23613185</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://arxiv.org/pdf/0710.0389v1','EPRINT'); return false;" href="http://arxiv.org/pdf/0710.0389v1"><span id="translatedtitle">Long wave expansions for water waves over random <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Anne de Bouard; Walter Craig; Oliver Díaz-Espinosa; Philippe Guyenne; Catherine Sulem</p> <p>2007-10-01</p> <p>In this paper, we study the motion of the free surface of a body of fluid over a variable bottom, in a long wave asymptotic regime. We assume that the bottom of the fluid region can be described by a stationary random process $\\beta(x, \\omega)$ whose variations take place on short length scales and which are decorrelated on the length scale of the long waves. This is a question of homogenization theory in the scaling regime for the Boussinesq and KdV equations. The analysis is performed from the point of view of perturbation theory for Hamiltonian PDEs with a small parameter, in the context of which we perform a careful analysis of the distributional convergence of stationary mixing random processes. We show in particular that the problem does not fully homogenize, and that the random effects are as important as dispersive and nonlinear phenomena in the scaling regime that is studied. Our principal result is the derivation of effective equations for surface water waves in the long wave small amplitude regime, and a consistency analysis of these equations, which are not necessarily Hamiltonian PDEs. In this analysis we compute the effects of random modulation of solutions, and give an explicit expression for the scattered component of the solution due to waves interacting with the random bottom. We show that the resulting influence of the random <span class="hlt">topography</span> is expressed in terms of a canonical process, which is equivalent to a white noise through Donsker's invariance principle, with one free parameter being the variance of the random process $\\beta$. This work is a reappraisal of the paper by Rosales & Papanicolaou \\cite{RP83} and its extension to general stationary mixing processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26561984','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26561984"><span id="translatedtitle">Mapping the <span class="hlt">Topography</span> of a Protein Energy Landscape.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hutton, Richard D; Wilkinson, James; Faccin, Mauro; Sivertsson, Elin M; Pelizzola, Alessandro; Lowe, Alan R; Bruscolini, Pierpaolo; Itzhaki, Laura S</p> <p>2015-11-25</p> <p>Protein energy landscapes are highly complex, yet the vast majority of states within them tend to be invisible to experimentalists. Here, using site-directed mutagenesis and exploiting the simplicity of tandem-repeat protein structures, we delineate a network of these states and the routes between them. We show that our target, gankyrin, a 226-residue 7-ankyrin-repeat protein, can access two alternative (un)folding pathways. We resolve intermediates as well as transition states, constituting a comprehensive series of snapshots that map early and late stages of the two pathways and show both to be polarized such that the repeat array progressively unravels from one end of the molecule or the other. Strikingly, we find that the protein folds via one pathway but unfolds via a different one. The origins of this behavior can be rationalized using the numerical results of a simple statistical mechanics model that allows us to visualize the equilibrium behavior as well as single-molecule folding/unfolding trajectories, thereby filling in the gaps that are not accessible to direct experimental observation. Our study highlights the complexity of repeat-protein folding arising from their symmetrical structures; at the same time, however, this structural simplicity enables us to dissect the complexity and thereby map the precise <span class="hlt">topography</span> of the energy landscape in full breadth and remarkable detail. That we can recapitulate the key features of the folding mechanism by computational analysis of the native structure alone will help toward the ultimate goal of designed amino-acid sequences with made-to-measure folding mechanisms-the Holy Grail of protein folding. PMID:26561984</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.T33B4667K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.T33B4667K"><span id="translatedtitle">A magmatic probe of dynamic <span class="hlt">topography</span> beneath western North America</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klöcking, M.; White, N. J.; Maclennan, J.</p> <p>2014-12-01</p> <p>A region centered on the Yellowstone hotspot and encompassing the Colorado Plateau sits at an elevation 2 km higher than the cratonic North America. This difference broadly coincides with tomographically observed variations in lithospheric thickness: ~120 km beneath western North America, ~240 km beneath the craton. Thermochronology of the Grand Canyon area, sedimentary flux to the Gulf of Mexico, and river profile inversion all suggest that regional uplift occurred in at least two separate stages. High resolution seismic tomographic models, using USArray data, have identified a ring of low velocity material beneath the edges of the Colorado Plateau. Magmatism coincides with these low velocity zones and shows distinct phases: an overall increase in volume around 40 Ma and a change from lithospheric to asthenospheric signatures around 5 Ma. Volcanism is also observed to migrate north-east with time. Here, we attempt to integrate these different observations with lithospheric thickness. A dynamic <span class="hlt">topography</span> model of progressive lithospheric erosion over a hot mantle plume might account for uplift as well as the temporal and spatial distribution of magmatism across western North America. Thinning of the lithosphere around the edges of the Colorado Plateau in combination with the hotter mantle potential temperature of a plume could create isostatic and dynamic uplift as well as allowing for melt production. To test this model, we have analysed around 100 samples from volcanic centers across western North America by ICP-MS for rare earth elements (REE). Most of the samples are younger than 5 Ma, and all of them have previously been analysed by XRF. Using trace element ratios such as La/Yb and Nb/Y we assess depth of melting and melt fraction, respectively. In addition, we use REE inversion modelling to estimate melt fractions as a function of depth and temperature of melting. The results are compared to existing constraints on lithospheric thickness and mantle potential temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010307','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010307"><span id="translatedtitle">Mapping the <span class="hlt">Topography</span> of Mercury with MESSENGER Laser Altimetry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sun, Xiaoli; Cavanaugh, John F.; Neumann, Gregory A.; Smith, David E..; Zubor, Maria T.</p> <p>2012-01-01</p> <p>The Mercury Laser Altimeter onboard MESSENGER involves unique design elements that deal with the challenges of being in orbit around Mercury. The Mercury Laser Altimeter (MLA) is one of seven instruments on NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. MESSENGER was launched on 3 August 2004, and entered into orbit about Mercury on 18 March 2011 after a journey through the inner solar system. This involved six planetary flybys, including three of Mercury. MLA is designed to map the <span class="hlt">topography</span> and landforms of Mercury's surface. It also measures the planet's forced libration (motion about the spin axis), which helps constrain the state of the core. The first science measurements from orbit taken with MLA were made on 29 March 2011 and continue to date. MLA had accumulated about 8.3 million laser ranging measurements to Mercury's surface, as of 31 July 2012, i.e., over six Mercury years (528 Earth days). Although MLA is the third planetary lidar built at the NASA Goddard Space Flight Center (GSFC), MLA must endure a much harsher thermal environment near Mercury than the previous instruments on Mars and Earth satellites. The design of MLA was derived in part from that of the Mars Orbiter Laser Altimeter on Mars Global Surveyor. However, MLA must range over greater distances and often in off-nadir directions from a highly eccentric orbit. In MLA we use a single-mode diode-pumped Nd:YAG (neodymium-doped yttrium aluminum garnet) laser that is highly collimated to maintain a small footprint on the planet. The receiver has both a narrow field of view and a narrow spectral bandwidth to minimize the amount of background light detected from the sunlit hemisphere of Mercury. We achieve the highest possible receiver sensitivity by employing the minimum receiver detection threshold.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990115791','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990115791"><span id="translatedtitle">Erosion of Terrestrial Rift Flank <span class="hlt">Topography</span>: A Quantitative Study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weissel, Jeffrey K.</p> <p>1999-01-01</p> <p>Many rifted or passive continental margins feature a seaward-facing erosional escarpment which abruptly demarcates deeply weathered, low relief, interior uplands from a deeply incised, high relief coastal zone. It is generally accepted that these escarpments originate at the time of continental rifting and propagate inland through the elevated rift flank <span class="hlt">topography</span> at rates on the order of 1 km/Myr over the course of a margin's history. Considering the length of passive margins worldwide and an average rift flank plateau height of several hundred meters, it is clear that sediment eroded from passive margins is an important component of the mass flux from continents to oceans through geologic time. The overall goal of the research reported here is to develop a quantitative understanding of the kinematics of escarpment propagation across passive margins and the underlying geological processes responsible for this behavior. Plateau-bounding escarpments in general exhibit two basic forms depending on the direction of surface water drainage on the plateau interior relative to the escarpment. Where surface water flows away from the escarpment, the escarpment takes the form of subdued embayments and promontories, such that its overall trend remains fairly straight as it evolves with time. Where upland streams flow across the escarpment, it takes the form of dramatic, narrow gorges whose heads appear to propagate up the plateau drainage systems as large-scale knickpoints. From work on the Colorado Plateau, Schmidt (1987) noted that the Colorado River is located much closer to the Grand Canyon's south rim, a drainage divide escarpment, than to the north rim, which is a gorge-like escarpment. The main implication is that the gorge-like form might be associated with higher long-term average erosion rates compared to the drainage divide escarpment type.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/8936728','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/8936728"><span id="translatedtitle">EEG spectral <span class="hlt">topography</span> in neurology: II. A new system and a theoretical comparison of interpolation techniques.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Satherley, B L; Jones, R D; Bones, P J</p> <p>1996-09-01</p> <p>An EEG spectral <span class="hlt">topography</span> system has been developed to produce maps of the time-averaged spectra of a 16-channel EEG. The design of this system is based upon the discussions of the contentious issues of <span class="hlt">topography</span> presented in Part I and a theoretical study of two-dimensional interpolation techniques. The comparison of techniques is based upon simulated electric fields on a three-layer spherical head model. Four two-dimensional interpolation techniques are investigated: bilinear, nearest neighbour, bicubic splines, and thin-plate splines. The most accurate method, a 2nd degree thin-plate spline, is employed in the new <span class="hlt">topography</span> system. The EEG spectral <span class="hlt">topography</span> system adopts the following procedures: the EEG is recorded using the 16 channel ipsilateral-ears montage; spectral analysis is applied to several overlapping epochs, relatively free of artifacts, of length 5.12 s; the averaged frequency spectrum is divided into specified frequency bands; for each channel, the average spectral component of each band is mapped onto a plane representing the head; and the maps are completed using 2nd degree thin-plate spline interpolation. A particular aim of the development was to produce a <span class="hlt">topography</span> system compatible with the present EEG recording system at Christchurch Hospital. This has been achieved and, consequently, the <span class="hlt">topography</span> system is of immediate clinical use. The system is currently part of a major clinical study. PMID:8936728</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1512898A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1512898A"><span id="translatedtitle">Spatial patterns in the evolution of Cenozoic dynamic <span class="hlt">topography</span> and its influence on the Antarctic continent</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, Lester; Ferraccioli, Fausto; Eagles, Graeme; Steinberger, Bernhard; Ritsema, Jeroen</p> <p>2013-04-01</p> <p>Our knowledge of dynamic <span class="hlt">topography</span> in Antarctica remains in an infancy stage compared to other continents. We assess the space-time variability in dynamic <span class="hlt">topography</span> in Antarctica by analysing grids of global dynamic <span class="hlt">topography</span> in the Cenozoic (and late Cretaceous) based on the tomographic model S40RTS. Our model reveals that the Gamburtsev Province and Dronning Maud Land, two of the major nucleation sites for the East Antarctic Ice Sheet (EAIS) were ~500 m higher 60 Ma ago. The increased elevation may have facilitated ephemeral ice cap development in the early Cenozoic. Between ca 25 and 50 Ma the northern Wilkes Subglacial Basin was ca 200 m higher than today and a major increase in regional elevation (>600 m) occurred over the last 20-15 Ma over the northern and southern Victoria Land in the Transantarctic Mountains (TAM). The most prominent signal is observed over the Ross Sea Rift (RSR) where predicted Neogene dynamic <span class="hlt">topography</span> exceeds 1,000 m. The flow of warm mantle from the West Antarctic Rift System (WARS)may have driven these dynamic <span class="hlt">topography</span> effects over the TAM and RSR. However, we found that these effects are comparatively less significant over the Marie Byrd Land Dome and the interior of the WARS. If these contrasting dynamic <span class="hlt">topography</span> effects are included, then the predicted elevations of the Ross Sea Embayment ca 20 Ma ago are more similar to the interior of the WARS, with significant implications for the early development of the West Antarctic Ice Sheet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JPhCS.311a2021R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JPhCS.311a2021R"><span id="translatedtitle">3D surface <span class="hlt">topography</span> of cylinder liner forecasting during plateau honing process</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reizer, R.; Pawlus, P.</p> <p>2011-08-01</p> <p>Areal surface <span class="hlt">topographies</span> after plateau honing process were measured. A correlation analysis of surface texture parameters was then carried out. As the results, the following parameters describing plateau honed cylinder 3D surface <span class="hlt">topography</span> were selected: amplitude Sq, Sz, spatial: Str, Std, hybrid S?q as well as functional: Spq, Svq and Smq. 3D surface <span class="hlt">topographies</span> were modeled. The modeled surface <span class="hlt">topographies</span> were correctly matched to measured ones in 77% of all analyzed cases. The plateau honing experiment was then carried out using an orthogonal selective research plan. Two machining parameters were input variables: coarse honing pressure pv and plateau honing time t. Chosen cylinder liners texture parameters were output values. As the result of the experiment, regression equations connecting plateau honing process parameters pv and t with recommended 3D surface <span class="hlt">topography</span> parameters were obtained. Finally, cylinder liner surface <span class="hlt">topographies</span> were predicted for various values of machining parameters. Proper matching accuracy of modeled to measured textures was assured in 67% of analyzed cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26706505','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26706505"><span id="translatedtitle">Surface <span class="hlt">topography</span> of hydroxyapatite promotes osteogenic differentiation of human bone marrow mesenchymal stem cells.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Wanlei; Han, Weiqi; He, Wei; Li, Jianlei; Wang, Jirong; Feng, Haotian; Qian, Yu</p> <p>2016-03-01</p> <p>Effective and safe induction of osteogenic differentiation is one of the key elements of bone tissue engineering. Surface <span class="hlt">topography</span> of scaffold materials was recently found to promote osteogenic differentiation. Utilization of this <span class="hlt">topography</span> may be a safer approach than traditional induction by growth factors or chemicals. The aim of this study is to investigate the enhancement of osteogenic differentiation by surface <span class="hlt">topography</span> and its mechanism of action. Hydroxyapatite (HA) discs with average roughness (Ra) of surface <span class="hlt">topography</span> ranging from 0.2 to 1.65?m and mean distance between peaks (RSm) ranging from 89.7 to 18.6?m were prepared, and human bone-marrow mesenchymal stem cells (hBMSCs) were cultured on these discs. Optimal osteogenic differentiation was observed on discs with surface <span class="hlt">topography</span> characterized by Ra ranging from 0.77 to 1.09?m and RSm ranging from 53.9 to 39.3?m. On this surface configuration of HA, hBMSCs showed oriented attachment, F-actin arrangement, and a peak in the expression of Yes-associated protein (YAP) and PDZ binding motif (TAZ) (YAP/TAZ). These results indicated that the surface <span class="hlt">topography</span> of HA promoted osteogenic differentiation of hBMSCs, possibly by increasing cell attachment and promoting the YAP/TAZ signaling pathway. PMID:26706505</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoJI.203.1263K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoJI.203.1263K"><span id="translatedtitle">High surface <span class="hlt">topography</span> related to upper mantle flow beneath Eastern Anatolia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Komut, Tolga</p> <p>2015-11-01</p> <p>Eastern Anatolia region between north-south colliding Arabian and Eurasian plates has no significant crustal root and shallow (upper) mantle flow beneath seems to be vertically supporting its high <span class="hlt">topography</span>. It has a high surface heat flow and the underlying mantle is characterized by low seismic velocity zones. Using a mantle density/temperature variation field derived from P-wave seismic velocity, current shallow mantle flow and resultant dynamic <span class="hlt">topography</span> of Eastern Anatolia and adjacent Arabian foreland and Caucasus areas were calculated along a vertical section. The section crosses the tectonic boundaries interrelated with slab bodies (high seismic velocity/cold regions) and the low velocity zones above the slabs. According to the modelling experiments, the surface <span class="hlt">topography</span> of Eastern Anatolia seems to be supported by shallow mantle flow dynamics. On the other hand, residual <span class="hlt">topography</span> for the region was calculated using high resolution crustal thickness data. Positive residual <span class="hlt">topography</span> that suggests an undercompensated state of Eastern Anatolia is in concordance with the dynamic <span class="hlt">topography</span> anomaly. The modelled local shallow mantle flow support due to the density contrast between hot (low velocity) zones and underlying cold slab bodies beneath the area may be the present-day snapshot of the mantle flow uplift in Eastern Anatolia presence of which was previously suggested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20030071095&hterms=patrick+smith&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpatrick%2Bsmith','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20030071095&hterms=patrick+smith&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpatrick%2Bsmith"><span id="translatedtitle">Localized Gravity/<span class="hlt">Topography</span> Admittance and Correlation Spectra on Mars: Implications for Regional and Global Evolution</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McGovern, Patrick J.; Solomon, Sean C.; Smith, David E.; Zuber, Maria T.; Simons, Mark; Wieczorek, Mark A.; Phillips, Roger J.; Neumann, Gregory A.; Aharonson, Oded; Head, James W.</p> <p>2002-01-01</p> <p>[i] From gravity and <span class="hlt">topography</span> data collected by the Mars Global Surveyor spacecraft we calculate gravity/<span class="hlt">topography</span> admittances and correlations in the spectral domain and compare them to those predicted from models of lithospheric flexure. On the basis of these comparisons we estimate the thickness of the Martian elastic lithosphere (T(sub e)) required to support the observed topographic load since the time of loading. We convert T(sub e) to estimates of heat flux and thermal gradient in the lithosphere through a consideration of the response of an elastic/plastic shell. In regions of high <span class="hlt">topography</span> on Mars (e.g., the Tharsis rise and associated shield volcanoes), the mass-sheet (small-amplitude) approximation for the calculation of gravity from <span class="hlt">topography</span> is inadequate. A correction that accounts for finite-amplitude <span class="hlt">topography</span> tends to increase the amplitude of the predicted gravity signal at spacecraft altitudes. Proper implementation of this correction requires the use of radii from the center of mass (collectively known as the planetary shape ) in lieu of <span class="hlt">topography</span> referenced to a gravitational equipotential. Anomalously dense surface layers or buried excess masses are not required to explain the observed admittances for the Tharsis Montes or Olympus Mons volcanoes when this correction is applied. Derived T, values generally decrease with increasing age of the lithospheric load, in a manner consistent with a rapid decline of mantle heat flux during the Noachian and more modest rates of decline during subsequent epochs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GGG....14.1333S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GGG....14.1333S"><span id="translatedtitle">Constraints on core-mantle boundary <span class="hlt">topography</span> from normal mode splitting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Soldati, Gaia; Koelemeijer, Paula; Boschi, Lapo; Deuss, Arwen</p> <p>2013-05-01</p> <p>The frequencies of Earth's normal modes are split by rotation, ellipticity, and internal structure of the Earth. Thus, models of mantle heterogeneity and discontinuity <span class="hlt">topography</span> generate splitting that may be tested against observations. We insert maps of core-mantle boundary (CMB) <span class="hlt">topography</span>, which are derived via either a purely seismic or a joint tomographic/geodynamic inversion of body waves data, on top of tomographic model S20RTS. We then calculate synthetic splitting functions for normal modes that have been shown to be sensitive to CMB <span class="hlt">topography</span> and compare these to observed normal mode splitting data. The CMB <span class="hlt">topography</span> maps obtained via geodynamically constrained tomography fit normal mode data better than purely seismic maps, in particular when the geodynamic constraint also accounts for the presence of post-perovskite in the D? region. We test the significance of the reduction in misfit using the concept of observability which suggests that normal modes are able to observe the difference between the different CMB <span class="hlt">topography</span> maps. In addition, we find that the statistical significance, assessed by checking what fraction of 1000 randomly generated CMB models achieve a comparatively good fit as the desired model, is higher than 92% for degree 2 and 98% for all degrees. In summary, we have identified a model of CMB <span class="hlt">topography</span> that fits body wave data and improves, at least to some extent, the fit to normal mode data, and is coherent with the large-scale pattern of deep mantle heterogeneity expected on the basis of convection modeling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.T24C..03Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.T24C..03Y"><span id="translatedtitle">The Impact of Drainage Reorganization on Cenozoic <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yanites, B. J.; Ehlers, T. A.</p> <p>2011-12-01</p> <p>Landscape evolution and the resulting sedimentary deposits are controlled by the development and organization of drainage basins. As a landscape evolves within a climatic and tectonic environment, drainage reorganization events can occur, where one river basin grows at the expense of another. The added discharge downstream of a river capture location will generate a transient topographic response. The records of these events are preserved the sedimentary record and modern <span class="hlt">topography</span>. Drainage reorganization has been proposed to occur in a number of major drainage systems around the world including the Colorado, Rhine, Snake, Yellow, Yangtze, Indus, and Zambezi rivers as well as a number of smaller rivers. Yet little work has focused on quantifying the topographic and erosional consequence of such events. Here we propose a simple model that quantifies the impacts of drainage capture on the evolution of a drainage basin. The model is based on the inverse slope-contributing drainage area relationship observed in rivers throughout the world and describes the expected river elevation change as drainage area is added (and therefore slopes lowered) by a capture event. Furthermore, we develop a numerical model of drainage capture that quantifies the transience of erosion and sediment production based on a shear stress dependent fluvial incision and sediment transport model. Our focus here is on quantifying the impact of capture of the Rhine/Aare river system (~45,000 km2) during the late Pliocene/early Pleistocene. Our models suggest 500-800 m of river elevation change (lowering profiles) occurred over short time periods (less than a million years), contributing as much as 0.4 mm/yr of erosion to the Alpine foreland and Swiss Alps when averaged over the last few million years. The predicted incision magnitudes are consistent with incision measured from the elevation of Pliocene and early Pleistocene river gravels, suggesting that the majority of incision across northern Switzerland can be explained by drainage reorganization. We also present estimates of incision magnitudes for other capture events around the world, and show that the erosion impacts of drainage reorganization events are capable of producing significant pulses of sediments out of the basin. This has implications for the interpretation of sedimentary deposits and their relation to tectonic and climatic changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012cosp...39.1359N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39.1359N"><span id="translatedtitle">Gravity, <span class="hlt">topography</span>, and magnetic field of Mercury from MESSENGER</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neumann, Gregory</p> <p>2012-07-01</p> <p>On 18 March 2011, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was inserted into a ˜12-hour, near-polar orbit around Mercury, with an initial periapsis altitude of 200 km, initial periapse latitude of 60°N, and apoapsis at ˜15,200 km altitude in the southern hemisphere. This orbit has permitted the mapping of regional gravitational structure in the northern hemisphere, and laser altimetry from the MESSENGER spacecraft has yielded a geodetically controlled elevation model for the same hemisphere. The shape of a planet combined with gravity provides fundamental information regarding its internal structure and geologic and thermal evolution. Elevations in the northern hemisphere exhibit a unimodal distribution with a dynamic range of 9.63 km, less than that of the Moon (19.9 km), but consistent with Mercury's higher surface gravitational acceleration. After one Earth-year in orbit, refined models of gravity and <span class="hlt">topography</span> have revealed several large positive gravity anomalies that coincide with major impact basins. These candidate mascons have anomalies that exceed 100 mGal and indicate substantial crustal thinning and superisostatic uplift of underlying mantle. An additional uncompensated 1000-km-diameter gravity and topographic high at 68°N, 33° E lies within Mercury's northern volcanic plains. Mercury's northern hemisphere crust is generally thicker at low latitudes than in the polar region. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/MR^2 = 0.353 ± 0.017, where M=3.30 × 10 ^{23} kg and R=2440 km are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of C_m/C = 0.452 ± 0.035. One proposed model for Mercury's radial density distribution consistent with these results includes silicate crust and mantle layers overlying a dense solid (possibly Fe-S) layer, a liquid Fe-rich outer core of radius 2030 ± 37 km, and an assumed solid inner core. Magnetic field measurements indicate a northward offset of Mercury's axial magnetic dipole from the geographic equator by 479 ± 3 km and provide evidence for a regional-scale magnetic field approximately collocated with the northern volcanic plains of possible crustal origin. These results from MESSENGER indicate a complex and asymmetric evolution of internal structure and dynamics in this end-member inner planet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120009897','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120009897"><span id="translatedtitle">Gravity, <span class="hlt">Topography</span>, and Magnetic Field of Mercury from Messenger</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Neumann, Gregory A.; Solomon, Sean C.; Zuber, Maria T.; Phillips, Roger J.; Barnouin, Olivier; Ernst, Carolyn; Goosens, Sander; Hauck, Steven A., II; Head, James W., III; Johnson, Catherine L.; Lemoine, Frank G.; Margot, Jean-Luc; McNutt, Ralph; Mazarico, Erwan M.; Oberst, Jurgen; Peale, Stanley J.; Perry, Mark; Purucker, Michael E.; Rowlands, David D.; Torrence, Mark H.</p> <p>2012-01-01</p> <p>On 18 March 2011, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was inserted into a 12-hour, near-polar orbit around Mercury, with an initial periapsis altitude of 200 km, initial periapse latitude of 60 deg N, and apoapsis at approximately 15,200 km altitude in the southern hemisphere. This orbit has permitted the mapping of regional gravitational structure in the northern hemisphere, and laser altimetry from the MESSENGER spacecraft has yielded a geodetically controlled elevation model for the same hemisphere. The shape of a planet combined with gravity provides fundamental information regarding its internal structure and geologic and thermal evolution. Elevations in the northern hemisphere exhibit a unimodal distribution with a dynamic range of 9.63 km, less than that of the Moon (19.9 km), but consistent with Mercury's higher surface gravitational acceleration. After one Earth-year in orbit, refined models of gravity and <span class="hlt">topography</span> have revealed several large positive gravity anomalies that coincide with major impact basins. These candidate mascons have anomalies that exceed 100 mGal and indicate substantial crustal thinning and superisostatic uplift of underlying mantle. An additional uncompensated 1000-km-diameter gravity and topographic high at 68 deg N, 33 deg E lies within Mercury's northern volcanic plains. Mercury's northern hemisphere crust is generally thicker at low latitudes than in the polar region. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/MR2 = 0.353 +/- 0.017, where M=3.30 x 10(exp 23) kg and R=2440 km are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of Cm/C = 0.452 +/- 0.035. One proposed model for Mercury's radial density distribution consistent with these results includes silicate crust and mantle layers overlying a dense solid (possibly Fe-S) layer, a liquid Fe-rich outer core of radius 2030 +/- 37 km, and an assumed solid inner core. Magnetic field measurements indicate a northward offset of Mercury's axial magnetic dipole from the geographic equator by 479 +/-3 km and provide evidence for a regional-scale magnetic field approximately collocated with the northern volcanic plains of possible crustal origin. These results from MESSENGER indicate a complex and asymmetric evolution of internal structure and dynamics in this end-member inner planet.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS33C1093C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS33C1093C"><span id="translatedtitle">The Ocean Surface <span class="hlt">Topography</span> JASON-CS/SENTINEL-6 Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cullen, R.; Francis, R.</p> <p>2014-12-01</p> <p>The Jason-CS/Sentinel-6 programme will consist of 2 spacecraft and will be the latest in a series of ocean surface <span class="hlt">topography</span> missions that will span nearly three decades. They follow the altimeters on-board TOPEX/Poseidon through to Jason-3 (expected March 2015). Jason-CS will continue to fulfil objectives of the reference series whilst introducing a major enhancement in capability providing the operational and science oceanographic community with the state of the art in terms of platform, measurement instrumentation design thus securing optimal operational and science data return. The programme is a part of the EC Copernicus initiative, whose objective is to support Europe's goals regarding sustainable development and global governance of the environment by providing timely and quality data, information, services and knowledge. The programme brings together: ESA for development, procurement & early orbit activities; EUMETSAT for mission management, ground segment, flight ops, contributing funding of the 1st satellite and participation in funding for the 2nd satellite; NOAA for US payload instruments, launcher, ground stations & operations; NASA for developing the US payload, launcher procurement and funding US science; EU for funding the operations and participation in funding (with EUMETSAT) for the 2nd satellite; CNES for mission expertise and provision of POD. The consortium plan to procure 2 satellites with the 1st planned for launch readiness in the 1st half of 2020 with the 2nd satellite 5 years later. The first major commitment to funding was given by the ESA member states that approved the programme in June 2014 and in addition the European Union funding is also secure. The design will be based on a platform derived from CryoSat-2 but adjusted to the specific requirements of the higher orbit. The principle payload instrument is a high precision Ku/C band radar altimeter with retrieval of geophysical parameters (surface elevation, wind speed and SWH) from the altimeter data require supporting measurements: a DORIS receiver for POD; The Climate Quality Advanced Microwave Radiometer (AMR-C) provided by JPL for high stability path delay correction. Orbit tracking data are also provided by GPS & LRA. An additional US GPS receiver, GNSS-RO, will be dedicated to radio-occultation measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoJI.203..384O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoJI.203..384O"><span id="translatedtitle">Effect of the Earth's surface <span class="hlt">topography</span> on quasi-dynamic earthquake cycles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohtani, Makiko; Hirahara, Kazuro</p> <p>2015-10-01</p> <p>We take account of the effect of Earth's surface <span class="hlt">topography</span> in quasi-dynamic earthquake cycle simulations using a boundary integral equation method. While we have so far assumed a homogeneous elastic half-space medium with a flat free surface, Earth's actual surface <span class="hlt">topography</span> is complicated. Here, we constructed new slip response functions in half-space with an arbitrarily shaped surface <span class="hlt">topography</span> in which we used slip response functions in full-space by introducing imaginary free surface cells in addition to embedded fault ones. By comparing analytical slip response functions in the case of a flat surface overlying half-space with the new ones, we developed a computationally efficient method for setting the Earth's surface region, which was divided into cells with the appropriate sizes depending on the fault source cell depth to maintain the computational accuracy. With these new slip response functions, we simulated simple interplate earthquake cycles in the region close to the Japan Trench, off Miyagi, Tohoku, in northeast Japan, which has the amplitude of 7 km in depth. Compared with the case where the flat surface level was set at the trench depth, the slip response functions for the case where actual seafloor <span class="hlt">topography</span> was used had smaller amplitudes. Hence, the actual <span class="hlt">topography</span> produces smaller recurrence times for earthquake cycles than that for the flat surface case. These effects of the actual Earth's surface <span class="hlt">topography</span> mainly come from changes in the distance between the surface and the fault compared with the flat surface case. Changes in the slip response function also represent changes in the fault stiffness of the system. Considering the actual <span class="hlt">topography</span> of the Earth's surface to be convex upwards as opposed to the flat, the fault stiffness becomes larger compared to the case of the flat Earth's surface. This leads to a change in the frictional instability, and sometime leads to the change in the way of rupture.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.C31A0581C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.C31A0581C"><span id="translatedtitle">The relationship between ice velocity and bed <span class="hlt">topography</span> on Byrd Glacier, Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Child, S.; Stearns, L. A.; Purdon, K.; Li, J.; Rodriguez-Morales, F.; Crowe, R.; Gomez-Garcia, D.</p> <p>2012-12-01</p> <p>Bed <span class="hlt">topography</span> controls the pattern and magnitude of ice velocity, far into the catchment basin of many Antarctic outlet glaciers. Predictive models of glacier dynamics and ice sheet mass balance rely on well-prescribed bed <span class="hlt">topography</span>, but in many regions bed <span class="hlt">topography</span> is largely unknown. This particular study investigates the relationship between bed and surface <span class="hlt">topography</span> and ice velocity in the catchment basin and trunk of Byrd Glacier. Byrd Glacier drains ~19 % of the area of the East Antarctic Ice Sheet (1,070,400 km2), and has the potential to play a significant role in the ice sheet's total mass balance. In 2011/2012, the Center for Remote Sensing of Ice Sheets (CReSIS) collected airborne radar data over Byrd Glacier. These new measurements of bed <span class="hlt">topography</span>, along with updated surface digital elevation models (DEMs) and basin-wide ice velocity maps, are used to investigate the flow dynamics of Byrd Glacier with improved accuracy. Surface DEMs are derived from new high-resolution WorldView imagery; ice velocity is derived from repeat visible imagery, coupled with InSAR results (Rignot et al., 2011). Results exhibit relatively smooth depressions surrounding the inferred subglacial lakes, ~200 km upflow of the grounding line on Byrd Glacier (Stearns et al., 2008). Downflow of the subglacial lakes is a complex pattern of hills and valleys as ice enters the glacier trunk. At the mouth of the trunk is a large overdeepening (~2500 m) that coincides with faster ice flow. We use along- and across-flow radar profiles to perform detailed comparisons of ice velocity, bed <span class="hlt">topography</span> and surface <span class="hlt">topography</span> throughout the Byrd Glacier region. Gridded products are used to complete an updated force balance assessment. These results provide us with a better understanding of Byrd Glacier's flow dynamics and sensitivity to external perturbations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990103109&hterms=spaceborne+laser&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dspaceborne%2Blaser','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990103109&hterms=spaceborne+laser&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dspaceborne%2Blaser"><span id="translatedtitle">The Laser Vegetation Imaging Sensor (LVIS): An Airborne Laser Altimeter for Mapping Vegetation and <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bryan, J.; Rabine, David L.</p> <p>1998-01-01</p> <p>The Laser Vegetation Imaging Sensor (LVIS) is an airborne laser altimeter designed to quickly and extensively map surface <span class="hlt">topography</span> as well as the relative heights of other reflecting surfaces within the laser footprint. Since 1997, this instrument has primarily been used as the airborne simulator for the Vegetation Canopy Lidar (VCL) mission, a spaceborne mission designed to measure tree height, vertical structure and ground <span class="hlt">topography</span> (including sub-canopy <span class="hlt">topography</span>). LVIS is capable of operating from 500 m to 10 km above ground level with footprint sizes from 1 to 60 m. Laser footprints can be randomly spaced within the 7 degree telescope field-of-view, constrained only by the operating frequency of the ND:YAG Q-switched laser (500 Hz). A significant innovation of the LVIS altimeter is that all ranging, waveform recording, and range gating are performed using a single digitizer, clock base, and detector. A portion of the outgoing laser pulse is fiber-optically fed into the detector used to collect the return signal and this entire time history of the outgoing and return pulses is digitized at 500 Msamp/sec. The ground return is then located using software digital signal processing, even in the presence of visibly opaque clouds. The surface height distribution of all reflecting surfaces within the laser footprint can be determined, for example, tree height and ground elevation. To date, the LVIS system has been used to monitor topographic change at Long Valley caldera, CA, as part of NASA's <span class="hlt">Topography</span> and Surface Change program, and to map tree structure and sub-canopy <span class="hlt">topography</span> at the La Selva Biological Research Station in Costa Rica, as part of the pre-launch calibration activities for the VCL mission. We present results that show the laser altimeter consistently and accurately maps surface <span class="hlt">topography</span>, including sub-canopy <span class="hlt">topography</span>, and vegetation height and structure. These results confirm the measurement concept of VCL and highlight the benefits of airborne prototypes of spaceborne instruments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.5114D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.5114D"><span id="translatedtitle">How to approximate viscoelastic dynamic <span class="hlt">topographies</span> of stagnant lid planetary bodies?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dumoulin, Caroline; ?adek, Ond?ej; Choblet, Gaël</p> <p>2013-04-01</p> <p>Planetary mantles are viscoelastic media. However, since numerical models of thermal convection in a viscoelastic spherical shell are still very challenging, most of the studies concerning dynamic <span class="hlt">topography</span> of planetary surfaces generated by mantle convection use one of the following simplified rheological set-up: i) IVF (instantaneous viscous flow), ii) viscous body with a free surface, or iii) hybrid methods combining viscous deformation and elastic filtering of the <span class="hlt">topography</span>. Justifications for the use of such approximations instead of a fully viscoelastic rheology have been made on the basis of simple tests with step-like viscosity structures, with small to moderate viscosity contrasts. However, because the rheology of planetary materials is thermally activated, the radial stratification of viscosity is more likely to be a continuous function of depth, and global viscosity contrasts might be very large. In our study, we systematically compare viscoelastic dynamic <span class="hlt">topography</span> induced by an internal load to <span class="hlt">topographies</span> generated by the three different simplified approaches listed above using a realistic viscosity profile for a stagnant lid associated to the lithosphere of a one plate planete. To this purpose, we compute response functions of surface <span class="hlt">topography</span> and geoid using three different semi-spectral models that all include self-gravitation: a) a linear Maxwell body with a pseudo free upper surface, b) a viscous body with a pseudo free upper surface, and c) a viscous body with a free-slip condition at the surface. Results obtained with this last model (IVF) can then be filtered using the elastic thin shell approximation: the effective elastic thickness then corresponds to the elastic thickness that is needed to fit the viscoelastic <span class="hlt">topography</span> with an elastic filtering of the IVF <span class="hlt">topography</span>. We show that the effective elastic thickness varies strongly with the degree of the load, with the depth of the load, and with the duration of the loading. These results naturally depend on the ratio between the mantle and the lithospheric thicknesses. We show that, in the case of Mars, it is not possible to approximate viscoelastic <span class="hlt">topographies</span> generated by a stable plume using the elastic filtering of viscous dynamic <span class="hlt">topographies</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.4450M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.4450M"><span id="translatedtitle">Integrated approach to estimate the ocean's time variable dynamic <span class="hlt">topography</span> including its covariance matrix</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Müller, Silvia; Brockmann, Jan Martin; Schuh, Wolf-Dieter</p> <p>2015-04-01</p> <p>The ocean's dynamic <span class="hlt">topography</span> as the difference between the sea surface and the geoid reflects many characteristics of the general ocean circulation. Consequently, it provides valuable information for evaluating or tuning ocean circulation models. The sea surface is directly observed by satellite radar altimetry while the geoid cannot be observed directly. The satellite-based gravity field determination requires different measurement principles (satellite-to-satellite tracking (e.g. GRACE), satellite-gravity-gradiometry (GOCE)). In addition, hydrographic measurements (salinity, temperature and pressure; near-surface velocities) provide information on the dynamic <span class="hlt">topography</span>. The observation types have different representations and spatial as well as temporal resolutions. Therefore, the determination of the dynamic <span class="hlt">topography</span> is not straightforward. Furthermore, the integration of the dynamic <span class="hlt">topography</span> into ocean circulation models requires not only the dynamic <span class="hlt">topography</span> itself but also its inverse covariance matrix on the ocean model grid. We developed a rigorous combination method in which the dynamic <span class="hlt">topography</span> is parameterized in space as well as in time. The altimetric sea surface heights are expressed as a sum of geoid heights represented in terms of spherical harmonics and the dynamic <span class="hlt">topography</span> parameterized by a finite element method which can be directly related to the particular ocean model grid. Besides the difficult task of combining altimetry data with a gravity field model, a major aspect is the consistent combination of satellite data and in-situ observations. The particular characteristics and the signal content of the different observations must be adequately considered requiring the introduction of auxiliary parameters. Within our model the individual observation groups are combined in terms of normal equations considering their full covariance information; i.e. a rigorous variance/covariance propagation from the original measurements to the final product is accomplished. In conclusion, the developed integrated approach allows for estimating the dynamic <span class="hlt">topography</span> and its inverse covariance matrix on arbitrary grids in space and time. The inverse covariance matrix contains the appropriate weights for model-data misfits in least-squares ocean model inversions. The focus of this study is on the North Atlantic Ocean. We will present the conceptual design and dynamic <span class="hlt">topography</span> estimates based on time variable data from seven satellite altimeter missions (Jason-1, Jason-2, Topex/Poseidon, Envisat, ERS-2, GFO, Cryosat2) in combination with the latest GOCE gravity field model and in-situ data from the Argo floats and near-surface drifting buoys.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MAR.H1357Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MAR.H1357Z"><span id="translatedtitle">Generation of internal gravity waves by tidal flow over random oceanic <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Jiajun; Zhang, Likun; Swinney, Harry</p> <p>2015-03-01</p> <p>Internal waves (IWs) are gravity waves that propagate within density-stratified fluids such as the ocean, atmosphere, and protoplanetary disks. IWs generated by tidal flow over oceanic <span class="hlt">topography</span> provide much of the energy needed to sustain vertical mixing, which plays a critical role in ocean circulation and global climate. Therefore, it is important to determine the amount of energy that is extracted from tidal flow over <span class="hlt">topography</span> and radiated into IWs. We conduct 2D numerical simulations to determine the IW power generated by tidal flow over random <span class="hlt">topographies</span> that have the seafloor spectrum. The power is found to saturate with increasing topographic roughness, and to scale linearly with the characteristic height of the <span class="hlt">topography</span>. The linear dependence on the topographic height is, surprisingly, nearly independent of the value of the exponent characterizing the topographic spectrum. Our results should lead to improved predictions of the IW power generated by tidal flow over global ocean <span class="hlt">topography</span>. Research supported by the Office of Naval Research and the Texas Advanced Computing Center. JZ is supported also by the President's Graduate Fellowship from the National University of Singapore.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.6654S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.6654S"><span id="translatedtitle">Mesozoic ocean basins and the link to modeled dynamic <span class="hlt">topography</span> of the circum-Arctic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shephard, Grace; Flament, Nicolas; Heine, Christian; Dietmar Müller, R.</p> <p>2013-04-01</p> <p>The tectonic evolution of the circum-Arctic is complex, punctuated by the opening and closing of several ocean basins, and the accretion and deformation of numerous autochthonous and allochthonous terranes. Here, we present a new plate tectonic reconstruction for the circum-Arctic and adjacent regions since the start of the Jurassic, incorporating the opening of the Amerasia Basin and associated closure of the South Anuyi Ocean. The location of palaeo-subduction zones can be used to infer mantle heterogeneity structure beneath north-eastern North America, the Canadian Arctic Islands, Northern Atlantic and Russia. We use this kinematic plate reconstruction to drive forward geodynamic models of mantle flow from which we compute the spatio-temporal evolution of dynamic <span class="hlt">topography</span>. The passage of the evolving circum-Arctic over subducting slabs is expected to impart long-wavelength subsidence followed by uplift. Separating the isostatic and dynamic contributions to circum-Arctic <span class="hlt">topography</span> is challenging because of the paucity of offshore and onshore regional datasets, and is complicated by multiple processes, including rifting, long-wavelength mantle flow, magmatic underplating, sediment loading, and volcanism. Therefore, we focus on the possible correlation between the evolution of long-wavelength <span class="hlt">topography</span> and post-Jurassic subduction zones. We compare the dynamic <span class="hlt">topography</span> predicted by our geodynamic models to residual <span class="hlt">topography</span>, published palaeo-geographic maps and anomalous tectonic subsidence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.C43C0623M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.C43C0623M"><span id="translatedtitle">The Importance of Basal <span class="hlt">Topography</span> for Greenland Ice Sheet Margin Hydrology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moustafa, S.; Rennermalm, A. K.; Smith, L. C.; Pitcher, L. H.; Chu, V. W.</p> <p>2012-12-01</p> <p>Nearly half of the Greenland ice sheet's total mass loss is controlled by surface mass balance, primarily driven by meltwater runoff exiting at its margin via supra-, en-, and sub-glacial drainage networks into fjords and pro-glacial lakes and rivers. Despite the importance of meltwater runoff, Greenland's hydrologic drainage patterns are not well understood. This is partly due to a scarcity of ice sheet meltwater runoff observations and detailed information about supra- and sub-glacial <span class="hlt">topography</span>, which are responsible for dictating runoff flow patterns. However, such data are available locally in southwest Greenland for the Akuliarusiarsuup Kuua (AK) River watershed. In this study, NASA IceBridge supra-glacial (Airborne Topographic Mapper (ATM)) and sub-glacial (Multichannel Coherent Radar Depth Sounder (MCoRDS)) <span class="hlt">topography</span> and in situ hydrologic data from 2009-2012 are used to study three nested riverine systems within the AK River watershed ranging from 8 to 101 km2. Examination of relationships between drainage patterns modeled from topographic data and actual ice sheet runoff losses provide insight into drainage basin delineation accuracy, scale-dependency, and surface and sub-glacial <span class="hlt">topography</span> controls on ice sheet margin hydrology. Finally, an assessment is made to determine the importance of incorporating basal <span class="hlt">topography</span> within meltwater runoff models versus surface <span class="hlt">topography</span> alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11324205','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11324205"><span id="translatedtitle">Wavelength-dependent roughness: a quantitative approach to characterizing the <span class="hlt">topography</span> of rough titanium surfaces.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wieland, M; Textor, M; Spencer, N D; Brunette, D M</p> <p>2001-01-01</p> <p><span class="hlt">Topographies</span> of grit-blasted, etched, grit-blasted and etched, and microfabricated and etched surfaces of commercially pure titanium have been investigated. Such surface <span class="hlt">topographies</span> vary across the scale range of interest for dental implants, extending from nanometers to millimeters. The complete characterization of <span class="hlt">topography</span> requires the use of complementary methods. This study compared the topographic characterization methods of non-contact laser profilometry, interference microscopy, stereo-scanning electron microscopy (stereo-SEM), and atomic force microscopy. Non-contact laser profilometry was shown to be a useful method to characterize topographic features in the micron to millimeter range, whereas interference microscopy and stereo-SEM can be employed down to the submicron range. Stereo-SEM is particularly useful for quantifying <span class="hlt">topographies</span> with complex, strongly corrugated ("sharp"), and high-aspect-ratio features and was shown to be complementary to non-contact laser profilometry and interference microscopy. Because of tip-related envelope problems, atomic force microscopy was not found to be suitable for the type of surfaces investigated in this study. Independent of the method used, the commonly used "integral" amplitude roughness parameters, such as Ra, Rq, or Rt, were often of limited value in the description of actual implant surfaces. The application of the wavelength-dependent roughness approach was shown to be an effective method for the description of surface <span class="hlt">topographies</span> in the complete range of characteristic roughness and is also a useful means of examining the effects of surface treatment processes. PMID:11324205</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoJI.203.1909A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoJI.203.1909A"><span id="translatedtitle">Calculating gravitationally self-consistent sea level changes driven by dynamic <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Austermann, J.; Mitrovica, J. X.</p> <p>2015-12-01</p> <p>We present a generalized formalism for computing gravitationally self-consistent sea level changes driven by the combined effects of dynamic <span class="hlt">topography</span>, geoid perturbations due to mantle convection, ice mass fluctuations and sediment redistribution on a deforming Earth. Our mathematical treatment conserves mass of the surface (ice plus ocean) load and the solid Earth. Moreover, it takes precise account of shoreline migration and the associated ocean loading. The new formalism avoids a variety of approximations adopted in previous models of sea level change driven by dynamic <span class="hlt">topography</span>, including the assumption that a spatially fixed isostatic amplification of `air-loaded' dynamic <span class="hlt">topography</span> accurately accounts for ocean loading effects. While our approach is valid for Earth models of arbitrary complexity, we present numerical results for a set of simple cases in which a pattern of dynamic <span class="hlt">topography</span> is imposed, the response to surface mass loading assumes that Earth structure varies only with depth and that isostatic equilibrium is maintained at all times. These calculations, involving fluid Love number theory, indicate that the largest errors in previous predictions of sea level change driven by dynamic <span class="hlt">topography</span> occur in regions of shoreline migration, and thus in the vicinity of most geological markers of ancient sea level. We conclude that a gravitationally self-consistent treatment of long-term sea level change is necessary in any effort to use such geological markers to estimate ancient ice volumes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4357464','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4357464"><span id="translatedtitle">Biodiversity of Jinggangshan Mountain: The Importance of <span class="hlt">Topography</span> and Geographical Location in Supporting Higher Biodiversity</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liu, Gang; Huang, Fang-Fang; Liu, Jin-Gang; Liao, Wen-Bo; Wang, Ying-Yong; Ren, Si-Jie; Chen, Chun-Quan; Peng, Shao-Lin</p> <p>2015-01-01</p> <p>Diversity is mainly determined by climate and environment. In addition, <span class="hlt">topography</span> is a complex factor, and the relationship between <span class="hlt">topography</span> and biodiversity is still poorly understood. To understand the role of <span class="hlt">topography</span>, i.e., altitude and slope, in biodiversity, we selected Jinggangshan Mountain (JGM), an area with unique <span class="hlt">topography</span>, as the study area. We surveyed plant and animal species richness of JGM and compared the biodiversity and the main geographic characteristics of JGM with the adjacent 4 mountains. Gleason’s richness index was calculated to assess the diversity of species. In total, 2958 spermatophyte species, 418 bryophyte species, 355 pteridophyte species and 493 species of vertebrate animals were recorded in this survey. In general, the JGM biodiversity was higher than that of the adjacent mountains. Regarding topographic characteristics, 77% of JGM’s area was in the mid-altitude region and approximately 40% of JGM’s area was in the 10°–20° slope range, which may support more vegetation types in JGM area and make it a biodiversity hotspot. It should be noted that although the impact of <span class="hlt">topography</span> on biodiversity was substantial, climate is still a more general factor driving the formation and maintenance of higher biodiversity. Topographic conditions can create microclimates, and both climatic and topographic conditions contribute to the formation of high biodiversity in JGM. PMID:25763820</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.G33E..07A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.G33E..07A"><span id="translatedtitle">SWOT, The Surface Water and Ocean <span class="hlt">Topography</span> Satellite Mission (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alsdorf, D.; Andreadis, K.; Bates, P. D.; Biancamaria, S.; Clark, E.; Durand, M. T.; Fu, L.; Lee, H.; Lettenmaier, D. P.; Mognard, N. M.; Moller, D.; Morrow, R. A.; Rodriguez, E.; Shum, C.</p> <p>2009-12-01</p> <p>Surface fresh water is essential for life, yet we have surprisingly poor knowledge of its variability in space and time. Similarly, ocean circulation fundamentally drives global climate variability, yet the ocean current and eddy field that affects ocean circulation and heat transport at the sub-mesoscale resolution and particularly near coastal and estuary regions, is poorly known. About 50% of the vertical exchange of water properties (nutrients, dissovled CO2, heat, etc) in the upper ocean is taking place at the sub-mesoscale. Measurements from the Surface Water and Ocean <span class="hlt">Topography</span> satellite mission (SWOT) will make strides in understanding these processes and improving global ocean models for studying climate change. SWOT is a swath-based interferometric-altimeter designed to acquire elevations of ocean and terrestrial water surfaces at unprecedented spatial and temporal resolutions. The mission will provide measurements of storage changes in lakes, reservoirs, and wetlands as well as estimates of discharge in rivers. These measurements are important for global water and energy budgets, constraining hydrodynamic models of floods, carbon evasion through wetlands, and water management, especially in developing nations. Perhaps most importantly, SWOT measurements will provide a fundamental understanding of the spatial and temporal variations in global surface waters, which for many countries are the primary source of water. An on-going effort, the “virtual mission” (VM) is designed to help constrain the required height and slope accuracies, the spatial sampling (both pixels and orbital coverage), and the trade-offs in various temporal revisits. Example results include the following: (1) Ensemble Kalman filtering of VM simulations recover water depth and discharge, reducing the discharge RMSE from 23.2% to 10.0% over an 84-day simulation period, relative to a simulation without assimilation. (2) Ensemble-based data assimilation of SWOT like measurements yields bathymetric slope and depth to within 3.0 microradians and 50 cm, respectively. (3) SWOT measurements of storage changes in lakes larger than 1 km2 will have relative errors generally less than 5% whereas errors for one-hectare size lakes will be about 20%. (4) SWOT estimates of discharge compared to a one-year model-based “truth” data set suggest that instantaneous discharge estimates will have a median relative RMSE of 10.9% and that 86% of all instantaneous errors will be less than 25%. (5) Based on a global distribution of gauge-based discharge and candidate SWOT orbits with varying spatial and temporal sampling, SWOT errors in instantaneous discharge will be less than 25% for rivers wider than 50 m, whereas errors in monthly discharge will be less than 20% for rivers with drainage areas larger than 7000 km2. (6) We estimate that currently available satellite nadir altimetry data cannot monitor more than 15% of the global lake volume variation, whereas from 50% to more than 65% of the global lake volume variation will be observed by SWOT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008NIMPB.266.2035D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008NIMPB.266.2035D"><span id="translatedtitle">White beam synchrotron <span class="hlt">topography</span> using a high resolution digital X-ray imaging detector</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Danilewsky, A. N.; Rack, A.; Wittge, J.; Weitkamp, T.; Simon, R.; Riesemeier, H.; Baumbach, T.</p> <p>2008-05-01</p> <p>X-ray <span class="hlt">topography</span> is a well known imaging technique to characterise strain and extended defects in single crystals. Topographs are typically collected on X-ray films. On the one hand such photographic films show a limited dynamic range and the production of films will be discontinued step by step in the near future. On the other hand new imaging detectors improved for X-ray tomography become more and more attractive even for <span class="hlt">topography</span> because of increasing resolution, dynamic range, speed and active area. In this paper we report about the upgrade of the TOPO-TOMO beamline at the synchrotron light source ANKA, Research Centre Karlsruhe, with a high resolution digital camera for the <span class="hlt">topography</span> use.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OPhy...13....4R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OPhy...13....4R"><span id="translatedtitle"><span class="hlt">Topography</span>, mechanical and tribological properties of nanocomposite carbon-palladium films</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rymarczyk, Joanna; Kolodziejczyk, Lukasz; Czerwosz, Elzbieta</p> <p>2015-01-01</p> <p>In this work, the differences in nanomechanical properties, <span class="hlt">topography</span> and morphology of carbonpalladium (C-Pd) films were studied. These films were prepared with a Physical Vapour Deposition method on various substrates with different technological parameters. We show that duration of the PVD process is a crucial factor affecting the palladium content in these films. The differences in thickness of films depend on the distance between source boats and substrates. The nanomechanical properties of C-Pd films were studied with nanoindentation. Their <span class="hlt">topography</span> and morphology was ascertained with Atomic Force Microscopy and Scanning Electron Microscopy. It was found that the mechanical properties of C-Pd films depend on the content of palladium and on the morphology and <span class="hlt">topography</span> of these films. The various types of carbon-palladium films containing palladium nanograins incorporated in a carbon matrix that were, investigated in this paper, seem to be promising materials for numerous applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.8021V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.8021V"><span id="translatedtitle">Noise-driven cooperative dynamics between vegetation and <span class="hlt">topography</span> in riparian zones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vesipa, R.; Camporeale, C.; Ridolfi, L.</p> <p>2015-10-01</p> <p>Riparian ecosystems exhibit complex biotic and abiotic dynamics, where the triad vegetation-sediments-stream determines the ecogeomorphological features of the river landscape. Random fluctuations of the water stage are a key trait of this triad, and a number of behaviors of the fluvial environment can be understood only taking into consideration the role of noise. In order to elucidate how randomness shape riparian transects, a stochastic model that takes into account the main links between vegetation, sediments, and the stream is adopted, emphasizing the capability of vegetation to alter the plot <span class="hlt">topography</span>. A minimalistic approach is pursued, and the probability density function of vegetation biomass is analytically evaluated in any transect plot. This probability density function strongly depends on the vegetation-<span class="hlt">topography</span> feedback. We demonstrate how the vegetation-induced modifications of the bed <span class="hlt">topography</span> create more suitable conditions for the survival of vegetation in a stochastically dominated environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015STP.....1a.104D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015STP.....1a.104D"><span id="translatedtitle">Taking account of <span class="hlt">topography</span> when calculating the resistance of the global atmospheric conductor (Russian Title: ???? ??????? ??? ?????????? ????????????? ??????????? ???????????? ??????????)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Denisenko, Valery; Yakubaylik, Oleg</p> <p>2015-03-01</p> <p>The role of <span class="hlt">topography</span> in the formation of the global electric circuit is analyzed. The <span class="hlt">topography</span> of the Earth's surface is defined by data base GLOBE, that gives the height above the mean sea level in geodetic coordinates with 30 angular seconds grid step. The atmosphere is considered as a global conductor between the Earth's surface and the ionosphere, which are simu-lated as ideal conductors. Empirical models of air conductivity are used. To simplify the description of large-scale phenomena the model is reduced to the one-dimensional simulation of the vertical columns of air. It is shown that the inclusion of the relief decreases the resistance of the atmosphere by 10 % and the local resistance over large mountains can be a few times de-creased. It is noted that in the more general models of the electrical conductivity of the atmosphere taking <span class="hlt">topography</span> into account is also essential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000110297&hterms=stationary&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dstationary','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000110297&hterms=stationary&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dstationary"><span id="translatedtitle">Stationary Wave Activity Simulated by the NASA Ames MGCM Incorporating New MOLA <span class="hlt">Topography</span> Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bridger, A. F. C.; Hollingsworth, J. L.; Haberle, R. M.; Schaeffer, J.</p> <p>1999-01-01</p> <p>Annual simulations of Mars' atmosphere have been conducted with the NASA Ames Mars General Circulation Model (MGCM) using the newly-acquired MOLA <span class="hlt">topography</span> data. The data is provided at 1 x 1 deg resolution, and is used by the MGCM at 7.5 x 9 deg resolution. The vertical domain in the simulations reported here extends to around 80 km. Simulated stationary wave activity is examined in each hemisphere as a function of season (at every 30 deg of Ls), dust loading (dust visible opacities of 0.3, 1, and 3), and <span class="hlt">topography</span> (comparing results with MOLA vs. Smith-Zuber <span class="hlt">topography</span>). Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMIN21B1480N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMIN21B1480N"><span id="translatedtitle">A framework for integration of scientific applications into the Open<span class="hlt">Topography</span> workflow</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nandigam, V.; Crosby, C.; Baru, C.</p> <p>2012-12-01</p> <p>The NSF-funded Open<span class="hlt">Topography</span> facility provides online access to Earth science-oriented high-resolution LIDAR <span class="hlt">topography</span> data, online processing tools, and derivative products. The underlying cyberinfrastructure employs a multi-tier service oriented architecture that is comprised of an infrastructure tier, a processing services tier, and an application tier. The infrastructure tier consists of storage, compute resources as well as supporting databases. The services tier consists of the set of processing routines each deployed as a Web service. The applications tier provides client interfaces to the system. (e.g. Portal). We propose a "pluggable" infrastructure design that will allow new scientific algorithms and processing routines developed and maintained by the community to be integrated into the Open<span class="hlt">Topography</span> system so that the wider earth science community can benefit from its availability. All core components in Open<span class="hlt">Topography</span> are available as Web services using a customized open-source Opal toolkit. The Opal toolkit provides mechanisms to manage and track job submissions, with the help of a back-end database. It allows monitoring of job and system status by providing charting tools. All core components in Open<span class="hlt">Topography</span> have been developed, maintained and wrapped as Web services using Opal by Open<span class="hlt">Topography</span> developers. However, as the scientific community develops new processing and analysis approaches this integration approach is not scalable efficiently. Most of the new scientific applications will have their own active development teams performing regular updates, maintenance and other improvements. It would be optimal to have the application co-located where its developers can continue to actively work on it while still making it accessible within the Open<span class="hlt">Topography</span> workflow for processing capabilities. We will utilize a software framework for remote integration of these scientific applications into the Open<span class="hlt">Topography</span> system. This will be accomplished by virtually extending the Open<span class="hlt">Topography</span> service over the various infrastructures running these scientific applications and processing routines. This involves packaging and distributing a customized instance of the Opal toolkit that will wrap the software application as an OPAL-based web service and integrate it into the Open<span class="hlt">Topography</span> framework. We plan to make this as automated as possible. A structured specification of service inputs and outputs along with metadata annotations encoded in XML can be utilized to automate the generation of user interfaces, with appropriate tools tips and user help features, and generation of other internal software. The Open<span class="hlt">Topography</span> Opal toolkit will also include the customizations that will enable security authentication, authorization and the ability to write application usage and job statistics back to the Open<span class="hlt">Topography</span> databases. This usage information could then be reported to the original service providers and used for auditing and performance improvements. This pluggable framework will enable the application developers to continue to work on enhancing their application while making the latest iteration available in a timely manner to the earth sciences community. This will also help us establish an overall framework that other scientific application providers will also be able to use going forward.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..DFD.R1003D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..DFD.R1003D"><span id="translatedtitle">Energy flux of internal waves generated by tidal flow over <span class="hlt">topography</span> beneath a turning depth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Drake, Matthew; Paoletti, M. S.; Lee, F. M.; Morrison, P. J.; Swinney, H. L.</p> <p>2012-11-01</p> <p>We present experimental and computational studies of internal gravity wave generation by tidal flow over 2D <span class="hlt">topography</span> in a stably stratified fluid designed to model the deep ocean. King et al. found that there exist regions in the deep ocean where the buoyancy frequency (proportional to the square root of the density gradient) becomes less than the tidal frequency [King et al., J. Geophys. Res. 117, C04008 (2012)]. Below such ``turning depths'' the internal gravity waves become evanescent. The effect of turning depths on global internal wave generation has not been examined. Here we present experiments and 2D Navier-Stokes simulations that determine the far-field energy flux as a function of the distance of the turning depth above the <span class="hlt">topography</span>. We examine how the energy flux depends on the tidal frequency, stratification, topographic profile, and the distance of the <span class="hlt">topography</span> below the turning depth. Supported by ONR MURI Grant N000141110701.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MeScT..23e4010S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MeScT..23e4010S"><span id="translatedtitle">Development of ballistics identification—from image comparison to <span class="hlt">topography</span> measurement in surface metrology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Song, J.; Chu, W.; Vorburger, T. V.; Thompson, R.; Renegar, T. B.; Zheng, A.; Yen, J.; Silver, R.; Ols, M.</p> <p>2012-05-01</p> <p>Fired bullets and ejected cartridge cases have unique ballistics signatures left by the firearm. By analyzing the ballistics signatures, forensic examiners can trace these bullets and cartridge cases to the firearm used in a crime scene. Current automated ballistics identification systems are primarily based on image comparisons using optical microscopy. The correlation accuracy depends on image quality which is largely affected by lighting conditions. Because ballistics signatures are geometrical micro-<span class="hlt">topographies</span> by nature, direct measurement and correlation of the surface <span class="hlt">topography</span> is being investigated for ballistics identification. A Two-dimensional and Three-dimensional <span class="hlt">Topography</span> Measurement and Correlation System was developed at the National Institute of Standards and Technology for certification of Standard Reference Material 2460/2461 bullets and cartridge cases. Based on this system, a prototype system for bullet signature measurement and correlation has been developed for bullet signature identifications, and has demonstrated superior correlation results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3623177','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3623177"><span id="translatedtitle">Effect of Micro- and Nanoscale <span class="hlt">Topography</span> on the Adhesion of Bacterial Cells to Solid Surfaces</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hsu, Lillian C.; Fang, Jean; Borca-Tasciuc, Diana A.; Worobo, Randy W.</p> <p>2013-01-01</p> <p>Attachment and biofilm formation by bacterial pathogens on surfaces in natural, industrial, and hospital settings lead to infections and illnesses and even death. Minimizing bacterial attachment to surfaces using controlled <span class="hlt">topography</span> could reduce the spreading of pathogens and, thus, the incidence of illnesses and subsequent human and financial losses. In this context, the attachment of key microorganisms, including Escherichia coli, Listeria innocua, and Pseudomonas fluorescens, to silica and alumina surfaces with micron and nanoscale <span class="hlt">topography</span> was investigated. The results suggest that orientation of the attached cells occurs preferentially such as to maximize their contact area with the surface. Moreover, the bacterial cells exhibited different morphologies, including different number and size of cellular appendages, depending on the topographical details of the surface to which they attached. This suggests that bacteria may utilize different mechanisms of attachment in response to surface <span class="hlt">topography</span>. These results are important for the design of novel microbe-repellant materials. PMID:23416997</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/978296','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/978296"><span id="translatedtitle">Structural Characterization of Doped GaSb Single Crystals by X-ray <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Honnicke, M.G.; Mazzaro, I.; Manica, J.; Benine, E.; M da Costa, E.; Dedavid, B. A.; Cusatis, C.; Huang, X. R.</p> <p>2009-09-13</p> <p>We characterized GaSb single crystals containing different dopants (Al, Cd and Te), grown by the Czochralski method, by x-ray <span class="hlt">topography</span> and high angular resolution x-ray diffraction. Lang <span class="hlt">topography</span> revealed dislocations parallel and perpendicular to the crystal's surface. Double-crystal GaSb 333 x-ray <span class="hlt">topography</span> shows dislocations and vertical stripes than can be associated with circular growth bands. We compared our high-angular resolution x-ray diffraction measurements (rocking curves) with the findings predicted by the dynamical theory of x-ray diffraction. These measurements show that our GaSb single crystals have a relative variation in the lattice parameter ({Delta}d/d) on the order of 10{sup -5}. This means that they can be used as electronic devices (detectors, for example) and as x-ray monochromators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3549305','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3549305"><span id="translatedtitle">GLUTATHIONE <span class="hlt">SYNTHESIS</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lu, Shelly C.</p> <p>2012-01-01</p> <p>BACKGROUND Glutathione (GSH) is present in all mammalian tissues as the most abundant non-protein thiol that defends against oxidative stress. GSH is also a key determinant of redox signaling, vital in detoxification of xenobiotics, regulates cell proliferation, apoptosis, immune function, and fibrogenesis. Biosynthesis of GSH occurs in the cytosol in a tightly regulated manner. Key determinants of GSH <span class="hlt">synthesis</span> are the availability of the sulfur amino acid precursor, cysteine, and the activity of the rate-limiting enzyme, glutamate cysteine ligase (GCL), which is composed of a catalytic (GCLC) and a modifier (GCLM) subunit. The second enzyme of GSH <span class="hlt">synthesis</span> is GSH synthetase (GS). SCOPE OF REVIEW This review summarizes key functions of GSH and focuses on factors that regulate the biosynthesis of GSH, including pathological conditions where GSH <span class="hlt">synthesis</span> is dysregulated. MAJOR CONCLUSIONS GCL subunits and GS are regulated at multiple levels and often in a coordinated manner. Key transcription factors that regulate the expression of these genes include NF-E2 related factor 2 (Nrf2) via the antioxidant response element (ARE), AP-1, and nuclear factor kappa B (NF?B). There is increasing evidence that dysregulation of GSH <span class="hlt">synthesis</span> contributes to the pathogenesis of many pathological conditions. These include diabetes mellitus, pulmonary and liver fibrosis, alcoholic liver disease, cholestatic liver injury, endotoxemia and drug-resistant tumor cells. GENERAL SIGNIFICANCE GSH is a key antioxidant that also modulates diverse cellular processes. A better understanding of how its <span class="hlt">synthesis</span> is regulated and dysregulated in disease states may lead to improvement in the treatment of these disorders. PMID:22995213</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/946355','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/946355"><span id="translatedtitle">A Generalized Subsurface Flow Parameterization Considering Subgrid Spatial Variability of Recharge and <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Huang, Maoyi; Liang, Xu; Leung, Lai R.</p> <p>2008-12-05</p> <p>Subsurface flow is an important hydrologic process and a key component of the water budget, especially in humid regions. In this study, a new subsurface flow formulation is developed that incorporates spatial variability of both <span class="hlt">topography</span> and recharge. It is shown through theoretical derivation and case studies that the power law and exponential subsurface flow parameterizations and the parameterization proposed by Woods et al.[1997] are all special cases of the new formulation. The subsurface flows calculated using the new formulation compare well with values derived from observations at the Tulpehocken Creek and Walnut Creek watersheds. Sensitivity studies show that when the spatial variability of <span class="hlt">topography</span> or recharge, or both is increased, the subsurface flows increase at the two aforementioned sites and the Maimai hillslope. This is likely due to enhancement of interactions between the groundwater table and the land surface that reduce the flow path. An important conclusion of this study is that the spatial variability of recharge alone, and/or in combination with the spatial variability of <span class="hlt">topography</span> can substantially alter the behaviors of subsurface flows. This suggests that in macroscale hydrologic models or land surface models, subgrid variations of recharge and <span class="hlt">topography</span> can make significant contributions to the grid mean subsurface flow and must be accounted for in regions with large surface heterogeneity. This is particularly true for regions with humid climate and relatively shallow groundwater table where the combined impacts of spatial variability of recharge and <span class="hlt">topography</span> are shown to be more important. For regions with arid climate and relatively deep groundwater table, simpler formulations, especially the power law, for subsurface flow can work well, and the impacts of subgrid variations of recharge and <span class="hlt">topography</span> may be ignored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TCD.....9.6495P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TCD.....9.6495P"><span id="translatedtitle">Characterizing Arctic sea ice <span class="hlt">topography</span> using high-resolution IceBridge data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petty, A. A.; Tsamados, M. C.; Kurtz, N. T.; Farrell, S. L.; Newman, T.; Harbeck, J. P.; Feltham, D. L.; Richter-Menge, J. A.</p> <p>2015-11-01</p> <p>We present an analysis of Arctic sea ice <span class="hlt">topography</span> using high resolution, three-dimensional, surface elevation data from the Airborne Topographic Mapper, flown as part of NASA's Operation IceBridge mission. Surface features in the sea ice cover are detected using a newly developed surface feature picking algorithm. We derive information regarding the height, volume and geometry of surface features from 2009-2014 within the Beaufort/Chukchi and Central Arctic regions. The results are delineated by ice type to estimate the topographic variability across first-year and multi-year ice regimes. The results demonstrate that Arctic sea ice <span class="hlt">topography</span> exhibits significant spatial variability, mainly driven by the increased surface feature height and volume (per unit area) of the multi-year ice that dominates the Central Arctic region. The multi-year ice <span class="hlt">topography</span> exhibits greater interannual variability compared to the first-year ice regimes, which dominates the total ice <span class="hlt">topography</span> variability across both regions. The ice <span class="hlt">topography</span> also shows a clear coastal dependency, with the feature height and volume increasing as a function of proximity to the nearest coastline, especially north of Greenland and the Canadian Archipelago. A strong correlation between ice <span class="hlt">topography</span> and ice thickness (from the IceBridge sea ice product) is found, using a square-root relationship. The results allude to the importance of ice deformation variability in the total sea ice mass balance, and provide crucial information regarding the tail of the ice thickness distribution across the western Arctic. Future research priorities associated with this new dataset are presented and discussed, especially in relation to calculations of atmospheric form drag.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.S23A2465M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.S23A2465M"><span id="translatedtitle"><span class="hlt">Topography</span>-dependent Eikonal Traveltime Tomography for Upper Crustal Structure beneath Irregular Surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, T.; Zhang, Z.</p> <p>2013-12-01</p> <p>Upper crustal seismic structure provides important linkage between the mapped surface geology and deep structure or geodynamics. Seismic P-wave velocity model of upper crust can be established by first-arrival traveltime tomography which faces challenge from irregular surface. As one feasible way to deal with irregular surface, the physical space is expanded by infilling lower velocity medium above the irregular surface, to keep classic eikonal equation solver usable in traveltime modelling. The unexpected consequences from this kind of dealing with irregular surface include the occurrence of unphysical ray paths by the transition from irregular surface of free boundary into inner discontinuity in the expanded calculation space. An alternative way, namely irregular surface flattening (with transformation between curvilinear and Cartesian coordinate systems) was recently proposed which resulted in the development of <span class="hlt">topography</span>-dependent eikonal equation and its solver for traveltime forward modelling. Here, we present <span class="hlt">topography</span>-dependent eikonal traveltime tomography for upper crustal seismic velocity model. Where, the backprojection algorithm was utilized to solve the linearized equations, first-arrival traveltime field and ray paths were calculated with <span class="hlt">topography</span>-dependent eikonal equation solver. Our tomography scheme was evaluated in the presence of <span class="hlt">topography</span> through three models with different <span class="hlt">topography</span> complexity and a real data acquired in the eastern Kunlun with complicate <span class="hlt">topography</span>. These results highlight the potential advantage of our irregular surface flattening scheme in keeping the free surface in physical and computational space. The comparison of tomography results between the conventional irregular surface expansion and our flattening schemes suggests the tomography scheme can be used to construct shallow seismic velocity structure in deep seismic sounding and even near surface velocity model building.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013CliPD...9.6683M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013CliPD...9.6683M"><span id="translatedtitle">Dependence of Eemian Greenland temperature reconstructions on the ice sheet <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Merz, N.; Born, A.; Raible, C. C.; Fischer, H.; Stocker, T. F.</p> <p>2013-12-01</p> <p>The influence of a reduced Greenland ice sheet (GrIS) on Greenland's surface climate during the Eemian interglacial is studied using a comprehensive climate model. We find a distinct impact of changes in the GrIS <span class="hlt">topography</span> on Greenland's surface air temperatures (SAT) even when correcting for changes in surface elevation which influences SAT through the lapse rate effect. The resulting lapse rate corrected SAT anomalies are thermodynamically driven by changes in the local surface energy balance rather than dynamically caused through anomalous advection of warm/cold air masses. The large-scale circulation is indeed very stable among all sensitivity experiments and the NH flow pattern does not depend on Greenland's <span class="hlt">topography</span> in the Eemian. In contrast, Greenland's surface energy balance is clearly influenced by changes in the GrIS <span class="hlt">topography</span> and this impact is seasonally diverse. In winter, the variable reacting strongest to changes in the <span class="hlt">topography</span> is the sensible heat flux (SHFLX). The reason is its dependence on surface winds, which themselves are controlled to a large extent by the shape of the GrIS. Hence, regions where a receding GrIS causes higher surface wind velocities also experience anomalous warming through SHFLX. Vice-versa, regions that become flat and ice-free are characterized by low wind speeds, low SHFLX and anomalous cold winter temperatures. In summer, we find surface warming induced by a decrease in surface albedo in deglaciated areas and regions which experience surface melting. The Eemian temperature records derived from Greenland proxies, thus, likely include a temperature signal arising from changes in the GrIS <span class="hlt">topography</span>. For the NEEM ice core site, our model suggests that up to 3.2 °C of the annual mean Eemian warming can be attributed to these <span class="hlt">topography</span>-related processes and hence is not necessarily linked to large-scale climate variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014CliPa..10.1221M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014CliPa..10.1221M"><span id="translatedtitle">Dependence of Eemian Greenland temperature reconstructions on the ice sheet <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Merz, N.; Born, A.; Raible, C. C.; Fischer, H.; Stocker, T. F.</p> <p>2014-06-01</p> <p>The influence of a reduced Greenland Ice Sheet (GrIS) on Greenland's surface climate during the Eemian interglacial is studied using a set of simulations with different GrIS realizations performed with a comprehensive climate model. We find a distinct impact of changes in the GrIS <span class="hlt">topography</span> on Greenland's surface air temperatures (SAT) even when correcting for changes in surface elevation, which influences SAT through the lapse rate effect. The resulting lapse-rate-corrected SAT anomalies are thermodynamically driven by changes in the local surface energy balance rather than dynamically caused through anomalous advection of warm/cold air masses. The large-scale circulation is indeed very stable among all sensitivity experiments and the Northern Hemisphere (NH) flow pattern does not depend on Greenland's <span class="hlt">topography</span> in the Eemian. In contrast, Greenland's surface energy balance is clearly influenced by changes in the GrIS <span class="hlt">topography</span> and this impact is seasonally diverse. In winter, the variable reacting strongest to changes in the <span class="hlt">topography</span> is the sensible heat flux (SHF). The reason is its dependence on surface winds, which themselves are controlled to a large extent by the shape of the GrIS. Hence, regions where a receding GrIS causes higher surface wind velocities also experience anomalous warming through SHF. Vice-versa, regions that become flat and ice-free are characterized by low wind speeds, low SHF, and anomalous low winter temperatures. In summer, we find surface warming induced by a decrease in surface albedo in deglaciated areas and regions which experience surface melting. The Eemian temperature records derived from Greenland proxies, thus, likely include a temperature signal arising from changes in the GrIS <span class="hlt">topography</span>. For the Eemian ice found in the NEEM core, our model suggests that up to 3.1 °C of the annual mean Eemian warming can be attributed to these <span class="hlt">topography</span>-related processes and hence is not necessarily linked to large-scale climate variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8571E..3DS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8571E..3DS"><span id="translatedtitle">OCT corneal <span class="hlt">topography</span> within ¼ diopter in the presence of saccadic eye movements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sayegh, Samir I.</p> <p>2013-03-01</p> <p>Refractive surgeons and cataract surgeons need accurate measurements of corneal curvature/power. Increased expectations of patients, the increasing number of patients having undergone prior surgeries and patients with corneal pathologies dictate the need for reliable curvature measurements to enhance the predictability and the quality of surgical outcomes. Eye movements can negatively influence these measurements. We present a model of eye movements based on peak saccade velocities and formulate criteria for obtaining OCT <span class="hlt">topography</span> within ¼ of a diopter. Using these criteria we illustrate how next generation MHz systems will allow full corneal OCT <span class="hlt">topography</span> in both healthy and pathological corneas</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://arxiv.org/pdf/0811.1171v1','EPRINT'); return false;" href="http://arxiv.org/pdf/0811.1171v1"><span id="translatedtitle">Sensitivity of a Barotropic Ocean Model to Perturbations of the Bottom <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Eugene Kazantsev</p> <p>2008-11-07</p> <p>In this paper, we look for an operator that describes the relationship between small errors in representation of the bottom <span class="hlt">topography</span> in a barotropic ocean model and the model's solution. The study shows that the model's solution is very sensitive to <span class="hlt">topography</span> perturbations in regions where the flow is turbulent. On the other hand, the flow exhibits low sensitivity in laminar regions. The quantitative measure of sensitivity is influenced essentially by the error growing time. At short time scales, the sensitivity exhibits the polynomial dependence on the error growing time. And in the long time limit, the dependence becomes exponential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870063001&hterms=Asthenosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DAsthenosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870063001&hterms=Asthenosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DAsthenosphere"><span id="translatedtitle">Dynamic <span class="hlt">topography</span> and gravity anomalies for fluid layers whose viscosity varies exponentially with depth</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Revenaugh, Justin; Parsons, Barry</p> <p>1987-01-01</p> <p>Adopting the formalism of Parsons and Daly (1983), analytical integral equations (Green's function integrals) are derived which relate gravity anomalies and dynamic boundary <span class="hlt">topography</span> with temperature as a function of wavenumber for a fluid layer whose viscosity varies exponentially with depth. In the earth, such a viscosity profile may be found in the asthenosphere, where the large thermal gradient leads to exponential decrease of viscosity with depth, the effects of a pressure increase being small in comparison. It is shown that, when viscosity varies rapidly, <span class="hlt">topography</span> kernels for both the surface and bottom boundaries (and hence the gravity kernel) are strongly affected at all wavelengths.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://arxiv.org/pdf/1505.06867.pdf','EPRINT'); return false;" href="http://arxiv.org/pdf/1505.06867.pdf"><span id="translatedtitle">A laboratory study of low-mode internal tide scattering by finite-amplitude <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Peacock, Thomas; Didelle, Henri; Viboud, Samuel; Dauxois, Thierry</p> <p>2015-01-01</p> <p>We present the first laboratory experimental results concerning the scattering of a low-mode internal tide by a gaussian <span class="hlt">topography</span>. Experiments performed at the Coriolis Platform in Grenoble used a recently-conceived internal wave generator as a means of producing a high-quality mode-1 wave field. The evolution of the wave field in the absence and presence of a supercritical Gaussian was studied by performing spatiotemporal modal decompositions of velocity field data obtained using Particle Image Velocimetry (PIV). The results support predictions that large-amplitude supercritical <span class="hlt">topography</span> produces significant reflection of the internal tide and transfer of energy from low to high modes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18097084','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18097084"><span id="translatedtitle">X-ray diffractometry and <span class="hlt">topography</span> of lattice plane curvature in thermally deformed Si wafer.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yi, J M; Chu, Y S; Argunova, T S; Domagala, J Z; Je, J H</p> <p>2008-01-01</p> <p>The correlation between the microscopic lattice plane curvature and the dislocation structure in thermal warpage of 200 mm-diameter Czochralski Si (001) wafers has been investigated using high-resolution X-ray diffractometry and <span class="hlt">topography</span>. It is found that the (004) lattice plane curvature is locally confined between two neighboring slip bands, with the rotation axis parallel to the slip bands. High-resolution <span class="hlt">topography</span> reveals that the curvature resulted from a fragmented dislocation structure. The local confinement is attributed to the multiplication of the dislocations that are generated between the two slip bands. PMID:18097084</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AIPC.1677f0016S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPC.1677f0016S"><span id="translatedtitle">Forward modeling of magnetotelluric transverse electric mode with <span class="hlt">topography</span> using finite element method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Susilawati, Anggie; Srigutomo, Wahyu</p> <p>2015-09-01</p> <p>2-D Numerical modeling of magnetotelluric method with <span class="hlt">topography</span> effect was made using finite element method. This model is created by modeling the subsurface structure. The model used is a homogeneous earth model and conductive anomaly model with overburden layer. Response of the model was then compared with the response from the model without considering the effect of <span class="hlt">topography</span>. Based on these responses, there is a difference between the two types of models. These differences suggest topographic effects should be incorporated into the modeling scheme.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1412740F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1412740F"><span id="translatedtitle">Sentinel-3 Surface <span class="hlt">Topography</span> Mission: Payload, Data Products and Cal/Val Preparation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Féménias, P.; Rebhan, H.; Donlon, C.; Buongiorno, A.; Mavrocordatos, C.</p> <p>2012-04-01</p> <p>Sentinel-3 is an Earth observation satellite mission designed for GMES to ensure the long-term collection of high-quality measurements delivered in an operational manner to GMES ocean, land, atmospheric, emergency and security services. Primary sentinel-3 <span class="hlt">topography</span> mission measurement requirements have been derived from GMES user needs as follows: • Sea surface <span class="hlt">topography</span> (SSH), significant wave height (Hs) and surface wind speed derived over the global ocean to an equivalent accuracy and precision as that presently achieved by ENVISAT Radar Altimeter-2 (RA-2). • Enhanced surface <span class="hlt">topography</span> measurements in the coastal zone, sea ice regions and over inland rivers, their tributaries and lakes. To address the above requirements, the Sentinel-3 <span class="hlt">Topography</span> payload will carry a Synthetic Aperture Radar Altimeter (SRAL) instrument, a passive microwave radiometer (MWR) a GPS receiver and laser retro-reflector for precise orbit determination providing continuing the legacy of ENVISAT RA-2 and Cryosat. Three level of timeliness are defined within GMES for the S-3 <span class="hlt">Topography</span> mission: • NRT products, delivered to the users in less than 3 hours after acquisition of data by the sensor, • Short time critical (STC) products, delivered to the users in less than 48 hours after the acquisition and, • Non-time critical (NTC) products delivered not later than 1 month after acquisition or from long-term archives. The Sentinel-3 <span class="hlt">topography</span> data products will provide continuity of ENVISAT type measurement capability in Europe to determine sea, ice and land surface <span class="hlt">topography</span> measurements with high accuracy, timely delivery and in a sustained operational manner for GMES users. The Sentinel-3 data will also provide fundamental inputs to a variety of value-adding downstream services for industry, government agencies, commercial users, service providers and appropriate regulatory authorities. The Calibration and Validation of the Sentinel-3 <span class="hlt">topography</span> products will nominally rely on the cross-comparison with the ESA Envisat Altimetry mission and will be a significant challenge due to the stringent S-3 mission measurement requirements and their safeguarding all over the mission lifetime.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040087511&hterms=self-assembly&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dself-assembly','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040087511&hterms=self-assembly&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dself-assembly"><span id="translatedtitle"><span class="hlt">Topography</span> and transport properties of oligo(phenylene ethynylene) molecular wires studied by scanning tunneling microscopy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dholakia, Geetha R.; Fan, Wendy; Koehne, Jessica; Han, Jie; Meyyappan, M.</p> <p>2003-01-01</p> <p>Conjugated phenylene(ethynylene) molecular wires are of interest as potential candidates for molecular electronic devices. Scanning tunneling microscopic study of the <span class="hlt">topography</span> and current-voltage (I-V) characteristics of self-assembled monolayers of two types of molecular wires are presented here. The study shows that the <span class="hlt">topography</span> and I-Vs, for small scan voltages, of the two wires are quite similar and that the electronic and structural changes introduced by the substitution of an electronegative N atom in the central phenyl ring of these wires does not significantly alter the self-assembly or the transport properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5491745','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5491745"><span id="translatedtitle"><span class="hlt">Topography</span> of glycosylation reactions in the rough endoplasmic reticulum membrane</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Perez, M.; Hirschberg, C.B.</p> <p>1986-05-25</p> <p>The translocation of UDP-glucose and GDP-mannose from an external to a luminal compartment has been examined in rat liver vesicles derived from the rough endoplasmic reticulum (RER). RER vesicles with the same topographical orientation as in vivo were incubated with a mixture of (/sup 3/H)UDP-glucose and UDP-(/sup 14/C)glucose to demonstrate that the intact sugar nucleotide was translocated into the lumen of the vesicles. The translocation of UDP-glucose was dependent on temperature and was saturable at high concentrations of the sugar nucleotide. The transfer of glucose to endogenous acceptors was dependent on the translocation of UDP-glucose into the lumen of the RER since leaky vesicles resulted in both a decrease in transport and transfer of glucose to endogenous acceptors. Preliminary results suggest that the mechanism of UDP-glucose transport into RER-derived vesicles is via a coupled exchange with luminal UMP. Using the same experimental approach to detect translocation of UDP-glucose into the lumen of RER vesicles, we were unable to detect transport of GDP-mannose. Incubation of leaky vesicles with GDP-mannose resulted in stimulation of the amount of mannose transferred to endogenous acceptors, in marked contrast to that observed for UDP-glucose and UDP-N-acetylglucosamine. These results suggest that whereas UDP-glucose is translocated across the RER membrane in vitro, GDP-mannose is not transported. In addition, these results tentatively suggest that there is asymmetric <span class="hlt">synthesis</span> of the lipid-linked oligosaccharides within the membrane of the RER.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www2.jpl.nasa.gov/srtm/SRTM_paper.pdf','EPRINT'); return false;" href="http://www2.jpl.nasa.gov/srtm/SRTM_paper.pdf"><span id="translatedtitle">The Shuttle Radar <span class="hlt">Topography</span> Mission Farr, Tom G., Paul A. Rosen, Edward Caro, Robert Crippen, Riley Duren, Scott Hensley, Michael</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>1 The Shuttle Radar <span class="hlt">Topography</span> Mission Farr, Tom G., Paul A. Rosen, Edward Caro, Robert Crippen Barbara, CA Douglas Alsdorf Ohio State University Columbus, OH The Shuttle Radar <span class="hlt">Topography</span> Mission Agencies, and flew in February 2000. It used dual radar antennas to acquire interferometric radar data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://websrv.mece.ualberta.ca/mrflynn/nif15.pdf','EPRINT'); return false;" href="http://websrv.mece.ualberta.ca/mrflynn/nif15.pdf"><span id="translatedtitle">Gravity current flow over sinusoidal <span class="hlt">topography</span> in a two-layer ambient Mitchell Nicholson and Morris R. Flynn</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Flynn, Morris R.</p> <p></p> <p>Gravity current flow over sinusoidal <span class="hlt">topography</span> in a two-layer ambient Mitchell Nicholson to IP: 142.244.179.59 On: Wed, 23 Sep 2015 15:10:24 #12;PHYSICS OF FLUIDS 27, 096603 (2015) Gravity released gravity currents propagating through a two-layer ambient and over sinusoidal <span class="hlt">topography</span></p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.5230S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.5230S"><span id="translatedtitle">Sequential assimilation of multi-mission dynamical <span class="hlt">topography</span> into a global finite-element ocean model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Skachko, S.; Danilov, S.; Janji?, T.; Schröter, J.; Sidorenko, D.; Savcenko, R.; Bosch, W.</p> <p>2009-04-01</p> <p>Sequential assimilation of ocean dynamic <span class="hlt">topography</span>, derived from altimeter data combined with a referenced earth geoid, into gen- eral circulation ocean models is a complex problem. Our previous study based on the finite-element ocean model (FEOM) revealed the existence of a significant systematical bias between the mean dynamic <span class="hlt">topography</span> of the model and ocean dynamic <span class="hlt">topography</span>. To overcome this problem an adiabatic pressure correction method was used which reduces model drift from the mean ocean dynamic <span class="hlt">topography</span>. Another difficulty for the sequential assimilation of surface data is related to projection of the surface perturbation update to the layers of the ocean model. To this end a method is used according to which the temperature and salinity are updated following the vertical structure of the first baroclinic mode. It is shown that the method leads to a partially successful assimilation approach reducing the RMS difference between the model and data from 16 cm to 2 cm. This improvement of the mean state was accompanied by significant improvement of temporal variability in our analysis. However, it remains suboptimal, showing a tendency in the forecast phase of returning toward a free run without data assimilation. To improve the analysis quality and to reduce the tendency of the model to reject the changes made by the filter another approach is proposed based on the correlation between a steric height and elevation variability. The results of such an approach are discussed and compared to the results of our previous work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2860220','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2860220"><span id="translatedtitle">Patterning of Novel Breast Implant Surfaces by Enhancing Silicone Biocompatibility, Using Biomimetic <span class="hlt">Topographies</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Barr, S.; Hill, E.; Bayat, A.</p> <p>2010-01-01</p> <p>Introduction and Aims: Silicone biocompatibility is dictated by cell-surface interaction and its understanding is important in the field of implantation. The role of surface <span class="hlt">topography</span> and its associated cellular morphology needs investigation to identify qualities that enhance silicone surface biocompatability. This study aims to create well-defined silicone <span class="hlt">topographies</span> and examine how breast tissue–derived fibroblasts react and align to these surfaces. Methods: Photolithographic microelectronic techniques were modified to produce naturally inspired <span class="hlt">topographies</span> in silicone, which were cultured with breast tissue–derived human fibroblasts. Using light, immunofluorescent and atomic force microscopy, the cytoskeletal reaction of fibroblasts to these silicone surfaces was investigated. Results: Numerous, well-defined micron-sized pillars, pores, grooves, and ridges were manufactured and characterized in medical grade silicone. Inimitable immunofluorescent microscopy represented in our high magnification images of vinculin, vimentin, and the actin cytoskeleton highlights the differences in fibroblast adhesion between fabricated silicone surfaces. These unique figures illustrate that fibroblast adhesion and the reactions these cells have to silicone can be manipulated to enhance biointegration between the implant and the breast tissue. An alteration of fibroblast phenotype was also observed, exhibiting the propensity of these surfaces to induce categorical remodeling of fibroblasts. Conclusions: This unique study shows that fibroblast reactions to silicone <span class="hlt">topographies</span> can be tailored to induce physiological changes in cells. This paves the way for further research necessary to develop more biocompatible constructs capable of eliminating capsular contracture by subverting the foreign body response. PMID:20458346</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://users.loni.usc.edu/~thompson/PDF/Frisoni2007BrainCortexLOAD.pdf','EPRINT'); return false;" href="http://users.loni.usc.edu/~thompson/PDF/Frisoni2007BrainCortexLOAD.pdf"><span id="translatedtitle">The <span class="hlt">topography</span> of grey matter involvement in early and late onset Alzheimer's disease</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Thompson, Paul</p> <p></p> <p>The <span class="hlt">topography</span> of grey matter involvement in early and late onset Alzheimer's disease Giovanni B, The National Centre for Research and Care of Alzheimer's and Mental Diseases, 3 Service of Neuroradiology and Telemedicine, IRCCS Centro San Giovanni di Dio FBF, The National Centre for Research and Care of Alzheimer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://topex.ucsd.edu/geodynamics/02_Tectonics_Triple_Junctions.ppt.pdf','EPRINT'); return false;" href="http://topex.ucsd.edu/geodynamics/02_Tectonics_Triple_Junctions.ppt.pdf"><span id="translatedtitle">Observations related to plate tectonics " Ocean and continent <span class="hlt">topography</span>, hypsometry, and crustal thickness.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Sandwell, David T.</p> <p></p> <p>· Observations related to plate tectonics " Ocean and continent <span class="hlt">topography</span>, hypsometry, and crustal and gravity anomaly Marine magnetic anomalies " · Plate tectonic theory ­ types of plate boundaries! · Plate of plate tectonics states that the lithosphere (strong layer) is divided into a small number of nearly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ifa.hawaii.edu/~norb1/Papers/2010-internal_preprint.pdf','EPRINT'); return false;" href="http://www.ifa.hawaii.edu/~norb1/Papers/2010-internal_preprint.pdf"><span id="translatedtitle">Expressions for Tidal Conversion at Seafloor <span class="hlt">Topography</span> using Physical-Space Integrals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Schörghofer, Norbert</p> <p></p> <p>by a bell- shaped <span class="hlt">topography</span> is calculated analytically to this order. A concise formalism using Hilbert. Through this process, energy of the barotropic tides is converted into internal wave energy (Wunsch, 1975 of internal wave propagation, it is called "subcritical". Bell (1975a,b) has obtained an explicit formula</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=poems&id=EJ997995','ERIC'); return false;" href="http://eric.ed.gov/?q=poems&id=EJ997995"><span id="translatedtitle">A <span class="hlt">Topography</span> of Collaboration: Methodology, Identity and Community in Self-Study of Practice Research</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hamilton, Mary Lynn; Pinnegar, Stefinee</p> <p>2013-01-01</p> <p>Through the use of the metaphoric tool of <span class="hlt">topography</span>, two educational researchers explore the development of their understanding of collaboration in self-study of teacher education practices research. The researchers communicate their perceptions through the presentation of four topographic moments. Each topographic moment is represented by a poem…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://kuscholarworks.ku.edu/handle/1808/18708','EPRINT'); return false;" href="http://kuscholarworks.ku.edu/handle/1808/18708"><span id="translatedtitle">The trough-system algorithm and its application to spatial modeling of Greenland subglacial <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Herzfeld, Ute C.; McDonald, Brian W.; Wallin, Bruce F.; Chen, Phillip A.; Mayer, Helmut; Paden, John D.; Leuschen, Carl</p> <p>2014-07-01</p> <p>Dynamic ice-sheet models are used to assess the contribution of mass loss from the Greenland ice sheet to sea-level rise. Mass transfer from ice sheet to ocean is in a large part through outlet glaciers. Bed <span class="hlt">topography</span> ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Behavior&id=EJ990842','ERIC'); return false;" href="http://eric.ed.gov/?q=Behavior&id=EJ990842"><span id="translatedtitle">Functions of Maladaptive Behavior in Intellectual and Developmental Disabilities: Behavior Categories and <span class="hlt">Topographies</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Rojahn, Johannes; Zaja, Rebecca H.; Turygin, Nicole; Moore, Linda; van Ingen, Daniel J.</p> <p>2012-01-01</p> <p>Research has shown that different maladaptive behavior categories may be maintained by different contingencies. We examined whether behavior categories or behavior <span class="hlt">topographies</span> determine functional properties. The "Questions about Behavioral Function" with its five subscales ("Attention", "Escape", "Nonsocial", "Physical", and "Tangible") was…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ics.uci.edu/~fowlkes/papers/Luna_et_al_TEC2011.pdf','EPRINT'); return false;" href="http://www.ics.uci.edu/~fowlkes/papers/Luna_et_al_TEC2011.pdf"><span id="translatedtitle">Multiscale Biomimetic <span class="hlt">Topography</span> for the Alignment of Neonatal and Embryonic Stem Cell-Derived Heart Cells</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Fowlkes, Charless</p> <p></p> <p>Multiscale Biomimetic <span class="hlt">Topography</span> for the Alignment of Neonatal and Embryonic Stem Cell- prised of biomimetic wrinkles that simulate the heart's complex anisotropic and multiscale architecture corneal and lens epi- thelial cells.3­13 The addition of a robust, scalable, and tunable biomimetic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://frederic.chambat.free.fr/geophy/chambat_valette_moon_published08.pdf','EPRINT'); return false;" href="http://frederic.chambat.free.fr/geophy/chambat_valette_moon_published08.pdf"><span id="translatedtitle">A stress interpretation scheme applied to lunar gravity and <span class="hlt">topography</span> data</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>A stress interpretation scheme applied to lunar gravity and <span class="hlt">topography</span> data F. Chambat1 and B to be directly related to the deviatoric stresses without any rheological assumptions. In this approach a new set above the corresponding equipotential surfaces and (2) the stress difference. The method is applied</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://topex.ucsd.edu/sandwell/publications/139.pdf','EPRINT'); return false;" href="http://topex.ucsd.edu/sandwell/publications/139.pdf"><span id="translatedtitle">SAR interferometry at Venus for <span class="hlt">topography</span> and change detection Franz J. Meyer a,b,n</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Sandwell, David T.</p> <p></p> <p>SAR interferometry at Venus for <span class="hlt">topography</span> and change detection Franz J. Meyer a,b,n , David T 1 March 2012 Received in revised form 4 October 2012 Accepted 5 October 2012 Keywords: Venus of Venus in the early 1990's, techniques of synthetic aperture radar interferometry (InSAR) have become</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.damtp.cam.ac.uk/lab/people/sd103/papers/2006/ISSF6_NyeDalziel.pdf','EPRINT'); return false;" href="http://www.damtp.cam.ac.uk/lab/people/sd103/papers/2006/ISSF6_NyeDalziel.pdf"><span id="translatedtitle">Scattering of internal gravity waves from rough <span class="hlt">topography</span> Abigail Nye and Stuart Dalziel</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Dalziel, Stuart</p> <p></p> <p>and subsequent mixing patterns near benthic <span class="hlt">topography</span>. This research aims to determine the scattering behaviour of internal gravity wave energy flux at boundaries containing topographic features of length scales for comparison with wavefields scattered from more complicated boundaries. Consideration of rough boundaries</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=functional+AND+training&pg=3&id=EJ821874','ERIC'); return false;" href="http://eric.ed.gov/?q=functional+AND+training&pg=3&id=EJ821874"><span id="translatedtitle">Evaluation of a Pre-Treatment Assessment to Select Mand <span class="hlt">Topographies</span> for Functional Communication Training</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ringdahl, Joel E.; Falcomata, Terry S.; Christensen, Tory J.; Bass-Ringdahl, Sandie M.; Lentz, Alison; Dutt, Anuradha; Schuh-Claus, Jessica</p> <p>2009-01-01</p> <p>Recent research has suggested that variables related to specific mand <span class="hlt">topographies</span> targeted during functional communication training (FCT) can affect treatment outcomes. These include effort, novelty of mands, previous relationships with problem behavior, and preference. However, there is little extant research on procedures for identifying which…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/ds765','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/ds765"><span id="translatedtitle">Coastal <span class="hlt">topography</span>–Northeast Atlantic coast, post-hurricane Sandy, 2012</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stockdon, Hilary F.; Doran, Kara S.; Sopkin, Kristin L.; Smith, Kathryn E.L.; Fredericks, Xan</p> <p>2013-01-01</p> <p>This Data Series contains lidar-derived bare-earth (BE) <span class="hlt">topography</span>, dune elevations, and mean-high-water shoreline position datasets for most sandy beaches for Fire Island, New York, and from Cape Henlopen, Delaware to Cape Lookout, North Carolina. The data were acquired post-Hurricane Sandy, which made landfall as an extratropical cyclone on October 29, 2012.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840018937','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840018937"><span id="translatedtitle">A critical assessment of viscous models of trench <span class="hlt">topography</span> and corner flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhang, J.; Hager, B. H.; Raefsky, A.</p> <p>1984-01-01</p> <p>Stresses for Newtonian viscous flow in a simple geometry (e.g., corner flow, bending flow) are obtained in order to study the effect of imposed velocity boundary conditions. Stress for a delta function velocity boundary condition decays as 1/R(2); for a step function velocity, stress goes as 1/R; for a discontinuity in curvature, the stress singularity is logarithmic. For corner flow, which has a discontinuity of velocity at a certain point, the corresponding stress has a 1/R singularity. However, for a more realistic circular-slab model, the stress singularity becomes logarithmic. Thus the stress distribution is very sensitive to the boundary conditions, and in evaluating the applicability of viscous models of trench <span class="hlt">topography</span> it is essential to use realistic geometries. <span class="hlt">Topography</span> and seismicity data from northern Hoshu, Japan, were used to construct a finite element model, with flow assumed tangent to the top of the grid, for both Newtonian and non-Newtonian flow (power law 3 rheology). Normal stresses at the top of the grid are compared to the observed trench <span class="hlt">topography</span> and gravity anomalies. There is poor agreement. Purely viscous models of subducting slables with specified velocity boundary conditions do not predict normal stress patterns compatible with observed <span class="hlt">topography</span> and gravity. Elasticity and plasticity appear to be important for the subduction process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Topography&id=EJ1007479','ERIC'); return false;" href="http://eric.ed.gov/?q=Topography&id=EJ1007479"><span id="translatedtitle">Effects of Fluency Instruction on Selection-Based and <span class="hlt">Topography</span>-Based Comprehension Measures</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Barnes, Clarissa S.; Rehfeldt, Ruth Anne</p> <p>2013-01-01</p> <p>A multiple probe across participants design was used to assess the effects of an intervention package on reading fluency and section-based and <span class="hlt">topography</span>-based comprehension tasks. Participants were three adolescents diagnosed with high functioning pervasive developmental disorders. The intervention package consisted of listen passage preview,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22113611','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22113611"><span id="translatedtitle">Upgraded X-ray <span class="hlt">topography</span> and microtomography beamline at the Kurchatov synchrotron radiation source</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Senin, R. A. Khlebnikov, A. S.; Vyazovetskova, A. E.; Blinov, I. A.; Golubitskii, A. O.; Kazakov, I. V.; Vorob'ev, A. A.; Buzmakov, A. V.; Asadchikov, V. E.; Shishkov, V. A.; Mukhamedzhanov, E. Kh.; Kovalchuk, M. V.</p> <p>2013-05-15</p> <p>An upgraded X-ray <span class="hlt">Topography</span> and Microtomography (XRT-MT) station is described, the parameters of the optical schemes and detectors are given, and the experimental possibilities of the station are analyzed. Examples of tomographic reconstructions are reported which demonstrate spatial resolutions of 2.5 and 10 {mu}m at fields of view of 2.5 and 10 mm, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1021840','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1021840"><span id="translatedtitle">Integrated Surface <span class="hlt">Topography</span> Characterization of Variously Polished Niobium for Superconducting Particle Accelerators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hui Tian, Charles Reece, Michael Kelley, G. Ribeill</p> <p>2009-05-01</p> <p>As superconducting niobium radio-frequency (SRF) cavities approach fundamental material limits, there is increased interest in understanding the details of topographical influences on realized performance limitations. Micro-and nano-roughness are implicated in both direct geometrical field enhancements as well as complications of the composition of the 50 nm surface layer in which the super-currents flow. Interior surface chemical polishing (BCP/EP) to remove mechanical damage leaves surface <span class="hlt">topography</span>, including pits and protrusions of varying sharpness. These may promote RF magnetic field entry, locally quenching superconductivity, so as to degrade cavity performance. A more incisive analysis of surface <span class="hlt">topography</span> than the widely-used average roughness is needed. In this study, a power spectral density (PSD) approach based on Fourier analysis of surface <span class="hlt">topography</span> data acquired by both stylus profilometry and atomic force microscopy (AFM) is being used to distinguish the scale-dependent smoothing effects. The topographical evolution of the Nb surface as a function of different steps of EP is reported, resulting in a novel qualitative and quantitative description of Nb surface <span class="hlt">topography</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.652a2005P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.652a2005P"><span id="translatedtitle">The change in the surface <span class="hlt">topography</span> of magnesium under high-flux C ion irradiation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Potyomkin, G. V.; Ligachev, A. E.; Zhidkov, M. V.; Kolobov, Y. R.; Remnev, G. E.; Y Gazizova, M.; Bozhko, S. A.; Pavlov, S. K.</p> <p>2015-11-01</p> <p>The <span class="hlt">topography</span> of the surface of the magnesium sample after irradiation by the high-intensity pulsed ion beam of a TEMP-4M accelerator was studied. The irradiation causes the formation of a regular comb structure and the creation of craters, their depth reaches 1-1.5 ?m.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=285022','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=285022"><span id="translatedtitle">Relationship between cotton yield and soil electrical conductivity, <span class="hlt">topography</span>, and landsat imagery</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Understanding spatial and temporal variability in crop yield is a prerequisite to implementing site-specific management of crop inputs. Apparent soil electrical conductivity (ECa), soil brightness, and <span class="hlt">topography</span> are easily obtained data that can explain yield variability. The objectives of this stu...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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