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Articles 391 - 420 of 586

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Be-10/Be-7 Tracer Of Atmospheric Transport And Stratosphere-Troposphere Exchange, C. Jordan, Jack E. Dibb, R C. Finkel Apr 2003

Be-10/Be-7 Tracer Of Atmospheric Transport And Stratosphere-Troposphere Exchange, C. Jordan, Jack E. Dibb, R C. Finkel

Earth Sciences

The 10Be/7Be ratio is a sensitive tracer of atmospheric transport and stratosphere-troposphere exchange (STE). Data from five NASA aircraft field missions (PEM: West A and B, Tropics A; SONEX; and SUCCESS) have been assembled to produce the largest data set of 10Be,7Be, and their ratio collected to date (>300 samples). Ratios near 0.60 are indicative of tropospheric air with little stratospheric influence, while higher ratios are found in stratospheric air. Samples from the lower stratosphere were all collected within 2.5 km of the tropopause and had ratios >1.27. Of these lower stratosphere samples …

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The International Bathymetric Chart Of The Arctic Ocean (Ibcao): An Improved Morphological Framework For Oceanographic Investigations, Ron Macnab, Martin Jakobsson Apr 2003

The International Bathymetric Chart Of The Arctic Ocean (Ibcao): An Improved Morphological Framework For Oceanographic Investigations, Ron Macnab, Martin Jakobsson

Center for Coastal and Ocean Mapping

The IBCAO initiative set out in late 1997 to assemble and merge all available bathymetric observations from northern regions, with the intent of constructing a reliable and up-to-date portrayal of the Arctic seabed in digital and printed form. In early 2000, a provisional grid and map were placed in circulation for public review and comment. Available for free downloading from a website hosted by the U.S. National Geophysical Data Center, these products won immediate acceptance from a broad spectrum of Arctic investigators who recognized the potential worth of the new information in a variety of applications ranging from straightforward map …

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Paleomagnetic Chronology Of Arctic Ocean Sediment Cores: Reversals And Excursions -The Conundrum, Reidar Lovlie, Martin Jakobsson, Jan Backman Apr 2003

Paleomagnetic Chronology Of Arctic Ocean Sediment Cores: Reversals And Excursions -The Conundrum, Reidar Lovlie, Martin Jakobsson, Jan Backman

Center for Coastal and Ocean Mapping

Chronologies of Arctic Ocean sediment cores are mainly based on interpretation of paleomagnetic inclination records. The first paleomagnetic chronology assigned zones with negative inclinations to polarity reversals (Steuerwald et al, 1968) because geomagnetic excursions at that time were a novel observation and had only been reported from lavas. Arctic Ocean sedimentation rates were thus established to be in the mm/ka-range. A general recognition of excursions as real features of the geomagnetic field emerged more than three decades later, and presently there is still no consensus regarding the number (or name), duration and age of global synchronous excursions within the Brunhes …

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Analysis Of Data Relevant To Establishing Outer Limits Of A Continental Shelf Under Law Of The Sea Article 76, Martin Jakobsson, Larry A. Mayer, Andy Armstrong Apr 2003

Analysis Of Data Relevant To Establishing Outer Limits Of A Continental Shelf Under Law Of The Sea Article 76, Martin Jakobsson, Larry A. Mayer, Andy Armstrong

Center for Coastal and Ocean Mapping

Coastal states may extend the limits of their juridically defined continental shelf beyond 200 nautical miles from their baselines under the provisions set forth in Article 76 of the United Nations Convention on the Law of the Sea (UNCLOS). In a preparatory desktop study, the University of New Hampshire’s Center for Coastal and Ocean Mapping/Joint Hydrographic Center analysed existing U.S. bathymetric and geophysical data holdings, identified data adequacy, and survey requirements to prepare a U.S. claim beyond the Exclusive Economical Zone (EEZ). In this paper we describe the methodology for our desktop study with particular emphasis on how we assembled …

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Fusing Information In A 3d Chart-Of-The-Future Display, Roland J. Arsenault, Matthew D. Plumlee, Shep M. Smith Lt, Colin Ware, Rick Brennan, Larry A. Mayer Mar 2003

Fusing Information In A 3d Chart-Of-The-Future Display, Roland J. Arsenault, Matthew D. Plumlee, Shep M. Smith Lt, Colin Ware, Rick Brennan, Larry A. Mayer

Center for Coastal and Ocean Mapping

No abstract provided.

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Providing The Third Dimension: High-Resolution Multibeam Sonar As A Tool For Archaeological Investigations - An Example From The D-Day Beaches Of Normandy, Larry A. Mayer, Brian R. Calder, J S. Schmidt, C Malzone Mar 2003

Providing The Third Dimension: High-Resolution Multibeam Sonar As A Tool For Archaeological Investigations - An Example From The D-Day Beaches Of Normandy, Larry A. Mayer, Brian R. Calder, J S. Schmidt, C Malzone

Center for Coastal and Ocean Mapping

In general, marine archaeological investigations begin in the archives, using historic maps, coast surveys, and other materials, to define submerged areas suspected to contain potentially significant historical sites. Following this research phase, a typical archaeological survey uses sidescan sonar and marine magnetometers as initial search tools. Targets are then examined through direct observation by divers, video, or photographs. Magnetometers can demonstrate the presence, absence, and relative susceptibility of ferrous objects but provide little indication of the nature of the target. Sidescan sonar can present a clear image of the overall nature of a target and its surrounding environment, but the …

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Marine Information Objects (Mio) And Ecdis: Concept And Practice, Lee Alexander Mar 2003

Marine Information Objects (Mio) And Ecdis: Concept And Practice, Lee Alexander

Center for Coastal and Ocean Mapping

Marine Information Objects (MIOs) consist of chart- and navigation-related information that supplement the minimum information required by ECDIS to ensure safety of navigation at sea. As related to the use of Electronic Navigational Chart (ENC) data, MIOs are additional, non-mandatory information not already covered by existing IMO, IHO, or IEC standards. Such information includes ice coverage, tide/water level, current flow, meteorological, oceanographic, and marine habitats. A Harmonization Group on MIOs (HGMIO) has been established between IHO and IEC to recommend additional data and display specifications that may be incorporated into future editions of IHO and IEC standards. This paper discusses …

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Electronic Chart Of The Future: The Hampton Roads Project, Rick Brennan, Colin Ware, Lee Alexander, Andy Armstrong, Larry A. Mayer, Lloyd C. Huff, Brian R. Calder, Shep M. Smith Lt, Matthew D. Plumlee, Roland J. Arsenault, Gerd Glang Mar 2003

Electronic Chart Of The Future: The Hampton Roads Project, Rick Brennan, Colin Ware, Lee Alexander, Andy Armstrong, Larry A. Mayer, Lloyd C. Huff, Brian R. Calder, Shep M. Smith Lt, Matthew D. Plumlee, Roland J. Arsenault, Gerd Glang

Center for Coastal and Ocean Mapping

ECDIS is evolving from a two-dimensional static display of chart-related data to a decision support system capable of providing real-time or forecast information. While there may not be consensus on how this will occur, it is clear that to do this, ENC data and the shipboard display environment must incorporate both depth and time in an intuitively understandable way. Currently, we have the ability to conduct high-density hydrographic surveys capable of producing ENCs with decimeter contour intervals or depth areas. Yet, our existing systems and specifications do not provide for a full utilization of this capability. Ideally, a mariner should …

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Fusing Information In A 3d Chart-Of-The-Future Display, Roland J. Arsenault, Shep M. Smith Lt, Colin Ware, Larry A. Mayer, Matthew D. Plumlee Mar 2003

Fusing Information In A 3d Chart-Of-The-Future Display, Roland J. Arsenault, Shep M. Smith Lt, Colin Ware, Larry A. Mayer, Matthew D. Plumlee

Center for Coastal and Ocean Mapping

The Data Visualization Research Lab at the Center for Coastal and Ocean Mapping is investigating how three-dimensional navigational displays can most effectively be constructed. This effort is progressing along multiple paths and is implemented in the GeoNav3D system, a 3D chart-of-the-future research prototype. We present two lines of investigation here. First, we explore how tide, depth, and planning information can be combined (fused) into a single view, in order to give the user a more realistic picture of effective water depths. In the GeoNav3D system, 3D shaded bathymetry, coded for color depth, is used to display navigable areas. As in …

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Effect Of Sulfate Aerosol On Tropospheric Nox And Ozone Budgets: Model Simulations And Topse Evidence, Xuexi Tie, L K. Emmons, Larry Horowitz, Guy Brasseur, Brian Ridley, Elliot Atlas, Craig Stround, Peter Hess, Andrzej Klonecki, Sasha Madronich, R. Talbot, Jack E. Dibb Feb 2003

Effect Of Sulfate Aerosol On Tropospheric Nox And Ozone Budgets: Model Simulations And Topse Evidence, Xuexi Tie, L K. Emmons, Larry Horowitz, Guy Brasseur, Brian Ridley, Elliot Atlas, Craig Stround, Peter Hess, Andrzej Klonecki, Sasha Madronich, R. Talbot, Jack E. Dibb

Earth Sciences

The distributions of NOx and O3 are analyzed during TOPSE (Tropospheric Ozone Production about the Spring Equinox). In this study these data are compared with the calculations of a global chemical/transport model (Model for OZone And Related chemical Tracers (MOZART)). Specifically, the effect that hydrolysis of N2O5 on sulfate aerosols has on tropospheric NOx and O3 budgets is studied. The results show that without this heterogeneous reaction, the model significantly overestimates NOx concentrations at high latitudes of the Northern Hemisphere (NH) in winter and spring in comparison to the observations during TOPSE; …

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Seasonal Distributions Of Fine Aerosol Sulfate In The North American Arctic Basin During Topse, Eric Scheuer, R. Talbot, Jack E. Dibb, Garry Seid, Linsey J. Debell, Barry Lefer Feb 2003

Seasonal Distributions Of Fine Aerosol Sulfate In The North American Arctic Basin During Topse, Eric Scheuer, R. Talbot, Jack E. Dibb, Garry Seid, Linsey J. Debell, Barry Lefer

Earth Sciences

We used the mist chamber/ion chromatography technique to quantify fine aerosol SO4=(<2.7 μm) in the Arctic during the Tropospheric Ozone Production about the Spring Equinox Experiment (TOPSE) with about 2.5 min time resolution. Our effective sample area ranged from 50° to 86°N and 53° to 100°W. The seasonal evolution of fine aerosol sulfate in the Arctic troposphere during TOPSE was consistent with the phenomenon of Arctic haze. Arctic haze has been attributed to pollution from sources in the Arctic and pollution transported meridionally along stable isentropes into the Arctic in geographically broad but vertically narrow bands. These layers became more prevalent at higher altitudes as the season progressed toward summer, and the relevant isentropes are not held so close to the surface. Mean fine particle SO4= mixing ratios during TOPSE in February below 1000 m were elevated (112 pptv) and highly variable (between 28 and 290 pptv) but were significantly lower at higher altitudes (about 40 pptv). As the season progressed, elevated mixing ratios and higher variability were observed at higher altitudes, up to 7 km. In May, mixing ratios at the lowest altitudes declined but still remained higher than in February at all altitudes. The high variability in our measurements likely reflects the vertical heterogeneity of the wintertime …

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An Estimate Of The Stratospheric Contribution To Springtime Tropospheric Ozone Maxima Using Topse Measurements And Beryllium-7 Simulations, Dale J. Allen, Jack E. Dibb, Brian Ridley, Kenneth E. Pickering, R. Talbot Feb 2003

An Estimate Of The Stratospheric Contribution To Springtime Tropospheric Ozone Maxima Using Topse Measurements And Beryllium-7 Simulations, Dale J. Allen, Jack E. Dibb, Brian Ridley, Kenneth E. Pickering, R. Talbot

Earth Sciences

Measurements of tropospheric ozone (O3) between 30°N and 70°N show springtime maxima at remote locations. The contribution of seasonal changes in stratosphere–troposphere exchange (STE) to these maxima was investigated using measurements from the Tropospheric Ozone Production about the Spring Equinox Experiment (TOPSE) campaign and the beryllium-7 (7Be) distribution from a calculation driven by fields from the Goddard Earth Observing System Data Assimilation System (GEOS DAS). Comparison with TOPSE measurements revealed that upper tropospheric model-calculated 7Be mixing ratios were reasonable (a change from previous calculations) but that lower tropospheric mixing ratios were too low most likely …

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Coupled Evolution Of Brox-Clox-Hox-Nox Chemistry During Bromine-Catalyzed Ozone Depletion Events In The Arctic Boundary Layer, M J. Evans, D J. Jacob, E L. Atlas, C A. Cantrell, Fred Eisele, F Flocke, A Fried, R L. Mauldin, Brian Ridley, B Wert, R. Talbot, D R. Blake, B J. Heikes, J Snow, J Walega, Andrew Weinheimer, Jack E. Dibb Feb 2003

Coupled Evolution Of Brox-Clox-Hox-Nox Chemistry During Bromine-Catalyzed Ozone Depletion Events In The Arctic Boundary Layer, M J. Evans, D J. Jacob, E L. Atlas, C A. Cantrell, Fred Eisele, F Flocke, A Fried, R L. Mauldin, Brian Ridley, B Wert, R. Talbot, D R. Blake, B J. Heikes, J Snow, J Walega, Andrew Weinheimer, Jack E. Dibb

Earth Sciences

Extensive chemical characterization of ozone (O3) depletion events in the Arctic boundary layer during the TOPSE aircraft mission in March–May 2000 enables analysis of the coupled chemical evolution of bromine (BrOx), chlorine (ClOx), hydrogen oxide (HOx) and nitrogen oxide (NOx) radicals during these events. We project the TOPSE observations onto an O3 chemical coordinate to construct a chronology of radical chemistry during O3 depletion events, and we compare this chronology to results from a photochemical model simulation. Comparison of observed trends in ethyne (oxidized by Br) and ethane …

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Stratospheric Influence On The Northern North American Free Troposphere During Topse: 7be As A Stratospheric Tracer, Jack E. Dibb, R. Talbot, Eric Scheuer, Garry Seid, Linsey J. Debell, Barry Lefer, Brian Ridley Feb 2003

Stratospheric Influence On The Northern North American Free Troposphere During Topse: 7be As A Stratospheric Tracer, Jack E. Dibb, R. Talbot, Eric Scheuer, Garry Seid, Linsey J. Debell, Barry Lefer, Brian Ridley

Earth Sciences

We use 7Be, with HNO3 and O3, to identify air masses sampled from the NCAR C-130 during TOPSE that retained clear evidence of stratospheric influence. A total of 43 such air masses, spread fairly evenly across the February to May sampling period, and 40°N–86°N latitude range, were encountered. South of 55°N, nearly all clear stratospheric influence was restricted to altitudes above 6 km. At higher latitudes stratospherically influenced air masses were encountered as low as 2 km. Approximately 12% of all TOPSE sampling time at altitudes above 2 km was spent in stratospherically impacted air, above …

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Ozone Depletion Events Observed In The High Latitude Surface Layer During The Topse Aircraft Program, Brian Ridley, Elliot Atlas, D Montzka, Edward V. Browell, C A. Cantrell, D R. Blake, N J. Blake, L Cinquini, Michael T. Coffey, L K. Emmons, Ronald C. Cohen, Russell J. Deyoung, Jack E. Dibb, Fred Eisele, F Flocke, A Fried, F E. Grahek, William B. Grant, Jonathan Hair, James W. Hannigan, B J. Heikes, Barry Lefer, R L. Mauldin, Jennie Moody, R E. Shetter, J Snow, R. Talbot, J A. Thornton, J Walega, Andrew Weinheimer, B Wert, Anthony Wimmers Feb 2003

Ozone Depletion Events Observed In The High Latitude Surface Layer During The Topse Aircraft Program, Brian Ridley, Elliot Atlas, D Montzka, Edward V. Browell, C A. Cantrell, D R. Blake, N J. Blake, L Cinquini, Michael T. Coffey, L K. Emmons, Ronald C. Cohen, Russell J. Deyoung, Jack E. Dibb, Fred Eisele, F Flocke, A Fried, F E. Grahek, William B. Grant, Jonathan Hair, James W. Hannigan, B J. Heikes, Barry Lefer, R L. Mauldin, Jennie Moody, R E. Shetter, J Snow, R. Talbot, J A. Thornton, J Walega, Andrew Weinheimer, B Wert, Anthony Wimmers

Earth Sciences

During the Tropospheric Ozone Production about the Spring Equinox (TOPSE) aircraft program, ozone depletion events (ODEs) in the high latitude surface layer were investigated using lidar and in situ instruments. Flight legs of 100 km or longer distance were flown 32 times at 30 m altitude over a variety of regions north of 58° between early February and late May 2000. ODEs were found on each flight over the Arctic Ocean but their occurrence was rare at more southern latitudes. However, large area events with depletion to over 2 km altitude in one case were found as far south as …

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Investigations Into Free Tropospheric New Particle Formation In The Central Canadian Arctic During The Winter/Spring Transition As Part Of Topse, R J. Weber, D A. Orsini, B Wang, Eric Scheuer, R. Talbot, Jack E. Dibb, Garry Seid, Linsey J. Debell, R L. Mauldin, E Kosciuch, C A. Cantrell, Fred Eisele Feb 2003

Investigations Into Free Tropospheric New Particle Formation In The Central Canadian Arctic During The Winter/Spring Transition As Part Of Topse, R J. Weber, D A. Orsini, B Wang, Eric Scheuer, R. Talbot, Jack E. Dibb, Garry Seid, Linsey J. Debell, R L. Mauldin, E Kosciuch, C A. Cantrell, Fred Eisele

Earth Sciences

In this paper, we investigate the role of in situ new particle production in the central Canadian sub-Arctic and Arctic as part of the TOPSE experiment. Airborne measurements conducted primarily in the free troposphere were made from 50° to 90°W longitude and 60° to 85°N latitude during the period from February to May 2000. Data pertinent to this paper include 3–4 nm diameter (Dp) particles, ultrafine condensation nuclei (Dp > 3 nm), fine particles (0.2 < Dp < 3 μm), and the possible nucleation precursor, sulfuric acid, and its precursor, sulfur dioxide. For data averaged over this period, most species showed little evidence for a latitudinal trend. Fine aerosol number concentrations, however, showed a slight increase with latitude. The evolution of various species concentrations over the period of the study show that fine particles also had a consistent temporal trend, increasing at all altitudes from February to May, whereas sulfur dioxide at the surface tended to peak in late March. Ultrafine condensation nuclei and 3–4 nm particles showed no temporal trends. Little evidence for in situ new particle production was observed during the study, except for one atypical event where SO2concentrations were 3.5 ppbv, 2 orders of magnitude higher than typical levels. This paper cannot address the question of whether the observed condensation nuclei were …

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Steady State Free Radical Budgets And Ozone Photochemistry During Topse, C A. Cantrell, Lee Mauldin, M Zondlo, Fred Eisele, E Kosciuch, R E. Shetter, Barry Lefer, S R. Hall, T L. Campos, Brian Ridley, J Walega, A Fried, B Wert, F Flocke, Andrew Weinheimer, James W. Hannigan, Michael T. Coffey, Elliot Atlas, S Stephens, B J. Heikes, J Snow, D R. Blake, N J. Blake, A Katzenstein, J Lopez, Edward V. Browell, Jack E. Dibb, Eric Scheuer, Garry Seid, R. Talbot Feb 2003

Steady State Free Radical Budgets And Ozone Photochemistry During Topse, C A. Cantrell, Lee Mauldin, M Zondlo, Fred Eisele, E Kosciuch, R E. Shetter, Barry Lefer, S R. Hall, T L. Campos, Brian Ridley, J Walega, A Fried, B Wert, F Flocke, Andrew Weinheimer, James W. Hannigan, Michael T. Coffey, Elliot Atlas, S Stephens, B J. Heikes, J Snow, D R. Blake, N J. Blake, A Katzenstein, J Lopez, Edward V. Browell, Jack E. Dibb, Eric Scheuer, Garry Seid, R. Talbot

Earth Sciences

A steady state model, constrained by a number of measured quantities, was used to derive peroxy radical levels for the conditions of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) campaign. The analysis is made using data collected aboard the NCAR/NSF C-130 aircraft from February through May 2000 at latitudes from 40° to 85°N, and at altitudes from the surface to 7.6 km. HO2 + RO2 radical concentrations were measured during the experiment, which are compared with model results over the domain of the study showing good agreement on the average. Average measurement/model ratios are 1.04 (σ …

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Springtime Photochemistry At Northern Mid And High Latitudes, Yuhang Wang, Brian Ridley, A Fried, C A. Cantrell, D D. Davis, Gao Chen, J Snow, B J. Heikes, R. Talbot, Jack E. Dibb, F Flocke, Andrew Weinheimer, N J. Blake, D R. Blake, R E. Shetter, Barry Lefer, Elliot Atlas, Michael T. Coffey, J Walega, B Wert Feb 2003

Springtime Photochemistry At Northern Mid And High Latitudes, Yuhang Wang, Brian Ridley, A Fried, C A. Cantrell, D D. Davis, Gao Chen, J Snow, B J. Heikes, R. Talbot, Jack E. Dibb, F Flocke, Andrew Weinheimer, N J. Blake, D R. Blake, R E. Shetter, Barry Lefer, Elliot Atlas, Michael T. Coffey, J Walega, B Wert

Earth Sciences

Physical and chemical properties of the atmosphere at 0–8 km were measured during the Tropospheric Ozone Production about the Spring Equinox (TOPSE) experiments from February to May 2000 at mid (40°–60°N) and high latitudes (60°–80°N). The observations were analyzed using a diel steady state box model to examine HOx and O3 photochemistry during the spring transition period. The radical chemistry is driven primarily by photolysis of O3 and the subsequent reaction of O(1D) and H2O, the rate of which increases rapidly during spring. Unlike in other tropospheric experiments, observed H2O2 …

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Tunable Diode Laser Measurements Of Formaldehyde During The Topse 2000 Study: Distributions, Trends, And Model Comparisons, A Fried, Yuhang Wang, C A. Cantrell, B Wert, J Walega, Brian Ridley, Elliot Atlas, R E. Shetter, Barry Lefer, Michael T. Coffey, James W. Hannigan, D R. Blake, N J. Blake, Simone Meinardi, R. Talbot, Jack E. Dibb, Eric Scheuer, Oliver Wingenter, J Snow, B J. Heikes, Dieter Ehhalt Feb 2003

Tunable Diode Laser Measurements Of Formaldehyde During The Topse 2000 Study: Distributions, Trends, And Model Comparisons, A Fried, Yuhang Wang, C A. Cantrell, B Wert, J Walega, Brian Ridley, Elliot Atlas, R E. Shetter, Barry Lefer, Michael T. Coffey, James W. Hannigan, D R. Blake, N J. Blake, Simone Meinardi, R. Talbot, Jack E. Dibb, Eric Scheuer, Oliver Wingenter, J Snow, B J. Heikes, Dieter Ehhalt

Earth Sciences

Airborne measurements of formaldehyde (CH2O) were acquired employing tunable diode laser absorption spectroscopy (TDLAS) during the 2000 Tropospheric Ozone Production About the Spring Equinox (TOPSE) study. This study consisted of seven deployments spanning the time period from 4 February to 23 May 2000 and covered a wide latitudinal band from 40°N to 85°N. The median measured CH2O concentrations, with a few exceptions, did not show any clear temporal trends from February to May in each of five altitude and three latitude bins examined. Detailed measurement–model comparisons were carried out using a variety of approaches employing two …

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Optically Stimulated Luminescence Dating Supports Central Arctic Ocean Cm-Scale Sedimentation Rates, Martin Jakobsson, Jan Backman, Andrew Murray, Reidar Lovlie Feb 2003

Optically Stimulated Luminescence Dating Supports Central Arctic Ocean Cm-Scale Sedimentation Rates, Martin Jakobsson, Jan Backman, Andrew Murray, Reidar Lovlie

Center for Coastal and Ocean Mapping

This paper presents new results from Optically Stimulated Luminescence (OSL) dating on a sediment core raised from the crest of the Lomonosov Ridge in the central Arctic Ocean. There has been much debate about dating sediment cores from the central Arctic Ocean and by using an independent absolute dating technique we aim to test whether or not relatively fast, cm-scale/ka, sedimentation rates were typical of Arctic’s Pleistocene depositional mode. On the basis of mainly paleomagnetic reversal stratigraphy, many previous studies suggest mm-scale/ka sedimentation rates. A common feature in these studies is that the first down core paleomagnetic negative inclination is …

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The Grounding Of An Ice Shelf In The Central Arctic Ocean: A Modeling Experiment, Martin Jakobsson, M Siegert, Mark Paton Jan 2003

The Grounding Of An Ice Shelf In The Central Arctic Ocean: A Modeling Experiment, Martin Jakobsson, M Siegert, Mark Paton

Center for Coastal and Ocean Mapping

A numerical ice sheet model was used in a first test towards evaluating the hypothesis that, during a period of large-scale glaciation, an ice shelf emanating from the Barents/Kara Seas grounded across parts of the Lomonosov Ridge to a depth of around 1000 m below present sea level (Jakobsson, 1999; Polyak et al., 2001). Despite that we not include complex ice shelf physics or grounding line mechanics in our model and treat the process of marine melting in a simple manner, our experiments are the necessary first steps toward providing a comprehensive reconstruction of the former ice-sheet/ice-shelf system in the …

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Seafloor Segmentation Based On Bathymetric Measurements From Multibeam Echosounders Data, Yuri Rzhanov, Randy G. Cutter Jr., Larry A. Mayer Jan 2003

Seafloor Segmentation Based On Bathymetric Measurements From Multibeam Echosounders Data, Yuri Rzhanov, Randy G. Cutter Jr., Larry A. Mayer

Center for Coastal and Ocean Mapping

Bathymetric data depicts the geomorphology of the seabottom and allows characterization of spatial distributions of apparent benthic habitats. The variability of seafloor topography can be defined as a texture. This prompts for the application of well developed image processing techniques for automatic delineation of regions with clucially different physiographic characteristics. In the present paper histograms of biologically motivated invariant image attributes are used for characterization of local geomorphological feahires. This technique can be naturally applied in a range of spatial scales. Local feature vectors are then submitted to a procedure which divides the set into a number of clusters each …

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Ozone, Aerosol, Potential Vorticity, And Trace Gas Trends Observed At High-Latitudes Over North America From February To May 2000, Edward V. Browell, Jonathan Hair, Carolyn Butler, William B. Grant, Russell J. Deyoung, Marta Fenn, Vincent G. Brackett, Marian B. Clayton, Lorraine A. Brasseur, David B. Harper, Brian Ridley, Andrzej Klonecki, Peter Hess, L K. Emmons, Xuexi Tie, Elliot Atlas, C A. Cantrell, Anthony Wimmers, D R. Blake, Michael T. Coffey, James W. Hannigan, Jack E. Dibb, R. Talbot, F Flocke, Andrew Weinheimer, A Fried, B Wert, J Snow, Barry Lefer Jan 2003

Ozone, Aerosol, Potential Vorticity, And Trace Gas Trends Observed At High-Latitudes Over North America From February To May 2000, Edward V. Browell, Jonathan Hair, Carolyn Butler, William B. Grant, Russell J. Deyoung, Marta Fenn, Vincent G. Brackett, Marian B. Clayton, Lorraine A. Brasseur, David B. Harper, Brian Ridley, Andrzej Klonecki, Peter Hess, L K. Emmons, Xuexi Tie, Elliot Atlas, C A. Cantrell, Anthony Wimmers, D R. Blake, Michael T. Coffey, James W. Hannigan, Jack E. Dibb, R. Talbot, F Flocke, Andrew Weinheimer, A Fried, B Wert, J Snow, Barry Lefer

Earth Sciences

Ozone (O3) and aerosol scattering ratio profiles were obtained from airborne lidar measurements on thirty-eight flights over seven deployments covering the latitudes of 40°–85°N between 4 February and 23 May 2000 as part of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) field experiment. Each deployment started from Broomfield, Colorado, with bases in Churchill, Canada, and on most deployments, Thule Air Base, Greenland. Nadir and zenith lidar O3 measurements were combined with in situ O3measurements to produce vertically continuous O3 profiles from near the surface to above the tropopause. Potential vorticity (PV) distributions …

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A World Class Ecdis Laboratory, Darrell H. Smith, Lee Alexander Jan 2003

A World Class Ecdis Laboratory, Darrell H. Smith, Lee Alexander

Center for Coastal and Ocean Mapping

No abstract provided.

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Automatic Statistical Processing Of Multibeam Echosounder Data, Brian R. Calder Jan 2003

Automatic Statistical Processing Of Multibeam Echosounder Data, Brian R. Calder

Center for Coastal and Ocean Mapping

This paper presents the CUBE (Combined Uncertainty and Bathymetry Estimator) algorithm. Our aim is to take advantage of statistical redundancy in dense Multibeam Echosounder data to identify outliers while tracking the uncertainty associated with the estimates that we make of the true depth in the survey area. We recognise that a completely automatic system is improbable, but propose that significant benefits can still be had if we can automatically process good quality data, and highlight areas that probably need further attention. We outline CUBE and its associated support structures, and apply it to a dataset from Woods Hole, MA, USA. …

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Mapping And Characterizing Subtidal Oyster Reefs Using Acoustic Techniques, Underwater Videography And Quadrat Counts, Raymond E. Grizzle, J R. Adams, Semme J. Dijkstra, Brian Smith, R W. Ward Jan 2003

Mapping And Characterizing Subtidal Oyster Reefs Using Acoustic Techniques, Underwater Videography And Quadrat Counts, Raymond E. Grizzle, J R. Adams, Semme J. Dijkstra, Brian Smith, R W. Ward

Center for Coastal and Ocean Mapping

Populations of the eastern oyster Crassostrea virginica have been in long-term decline in most areas. A major hindrance to effective oyster management has been lack of a methodology for accurately and economically obtaining data on their distribution and abundance patterns. Here, we describe early results from studies aimed at development of a mapping and monitoring protocol involving acoustic techniques, underwater videography, and destructive sampling (excavated quadrats). Two subtidal reefs in Great Bay, New Hampshire, were mapped with side-scan sonar and with videography by systematically imaging multiple sampling cells in a grid covering the same areas. A single deployment was made …

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On The Effect Of Random Errors In Gridded Bathymetric Compilations, Martin Jakobsson, Brian R. Calder, Larry A. Mayer Dec 2002

On The Effect Of Random Errors In Gridded Bathymetric Compilations, Martin Jakobsson, Brian R. Calder, Larry A. Mayer

Center for Coastal and Ocean Mapping

We address the problem of compiling bathymetric data sets with heterogeneous coverage and a range of data measurement accuracies. To generate a regularly spaced grid, we are obliged to interpolate sparse data; our objective here is to augment this product with an estimate of confidence in the interpolated bathymetry based on our knowledge of the component of random error in the bathymetric source data. Using a direct simulation Monte Carlo method, we utilize data from the International Bathymetric Chart of the Arctic Ocean database to develop a suitable methodology for assessment of the standard deviations of depths in the interpolated …

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Arctic Ocean Physiography, Martin Jakobsson, Arthur Grantz, Yngue Kristoffersen, Ron Macnab Dec 2002

Arctic Ocean Physiography, Martin Jakobsson, Arthur Grantz, Yngue Kristoffersen, Ron Macnab

Center for Coastal and Ocean Mapping

The first order physiographic provinces of the Arctic Ocean has been defined using the recently updated International Bathymetric Chart of the Arctic Ocean (IBCAO) grid model as the main database and a semi-quantitative approach. The first step in our classification of physiographic provinces is an evaluation of seafloor gradients contained in a slope model that was derived from the IBCAO grid. The slope information reveals certain seafloor process-related features, which add to the bathymetric information. Using interactive 3D-visualization, the slope and bathymetric information were simultaneously analyzed and certain slope intervals of the Arctic Ocean seafloor were found to generally characterize …

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Multi-Scale Visualization Of Remote Sensing And Topographic Data Of The Amazon Rain Forest, Luciano E. Fonseca, F P. Miranda, C Beisl, J Souza-Fonseca Dec 2002

Multi-Scale Visualization Of Remote Sensing And Topographic Data Of The Amazon Rain Forest, Luciano E. Fonseca, F P. Miranda, C Beisl, J Souza-Fonseca

Center for Coastal and Ocean Mapping

PETROBRAS (the Brazilian national oil company) built a pipeline to transport crude oil from the Urucu River region to a terminal in the vicinities of Coari, a city located in the right margin of the Solimoes River. The oil is then shipped by tankers to another terminal in Manaus, capital city of the Amazonas state. At the city of Coari, changes in water level between dry and wet seasons reach up to 14 meters. This strong seasonal character of the Amazonian climate gives rise to four distinct scenarios in the annual hydrological cycle: low water, high water, receding water, and …

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An Integrated Bathymetric And Topographic Digital Terrain Model Of The Canadian Arctic Archipelago, Goran Alm, Ron Macnab, Martin Jakobsson, Johan Kleman, Mark Mccracken Dec 2002

An Integrated Bathymetric And Topographic Digital Terrain Model Of The Canadian Arctic Archipelago, Goran Alm, Ron Macnab, Martin Jakobsson, Johan Kleman, Mark Mccracken

Center for Coastal and Ocean Mapping

No abstract provided.

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