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Oceanography and Atmospheric Sciences and Meteorology

2001

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Articles 1 - 30 of 197

Full-Text Articles in Physical Sciences and Mathematics

Seafloor Characterization From Spatial Variation Of Multibeam Backscatter Vs. Grazing Angle, Tianhang Hou, Lloyd C. Huff, Yuri Rzhanov, Larry A. Mayer Dec 2001

Seafloor Characterization From Spatial Variation Of Multibeam Backscatter Vs. Grazing Angle, Tianhang Hou, Lloyd C. Huff, Yuri Rzhanov, Larry A. Mayer

Center for Coastal and Ocean Mapping

Backscatter vs. grazing angle, which can be extracted from multibeam backscatter data, depend on characteristics of the multibeam system and the angular responses of backscatter that are characteristic of different seafloor properties, such as sediment hardness and roughness. Changes in backscatter vs. grazing angle that are contributed by the multibeam system normally remain fixed over both space and time. Therefore, they can readily be determined and removed from backscatter data. The variation of backscatter vs. grazing angle due to the properties of sediments will vary from location to location, as sediment type changes. The sediment component of variability can be …

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Improvement To The International Bathymetric Chart Of The Arctic Ocean (Ibcao): Updating The Data Base And The Grid Model, Martin Jakobsson, Norman Cherkis Dec 2001

Improvement To The International Bathymetric Chart Of The Arctic Ocean (Ibcao): Updating The Data Base And The Grid Model, Martin Jakobsson, Norman Cherkis

Center for Coastal and Ocean Mapping

The project to develop the IBCAO grid model was initiated in 1997 with the objective of providing to the Arctic research community an improved portrayal of the seabed north of 64-deg N, in a form suitable for digital manipulation and visualization. The model was constructed from a compilation of all single-beam and multibeam echo soundings that were available for the polar region, complemented where appropriate by newly released contour information. The grid features a cell size of 2.5 x 2.5 km on a polar stereographic projection; it is constructed on the WGS 84 datum, with true scale at 75-deg N. …

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1998 Debris Flows Near The Yakima River, Kittitas County, Washington—Some Geomorphic Implications, Martin R. Kaatz Dec 2001

1998 Debris Flows Near The Yakima River, Kittitas County, Washington—Some Geomorphic Implications, Martin R. Kaatz

Geography Faculty Scholarship

The geomorphic consequences of debris flows and their asso- ciated storms have been documented in many parts of the United States. Few, if any, have been studied and documented in central Washington. The importance of recurrent debris flows in sculpting Washington landscapes has not been generally recognized compared to other processes. Arid and semi-arid regions are particularly vulnerable to debris flows triggered by sudden intense thunderstorms. Most such areas are sparsely populated and eyewitnesses are uncommon. By contrast, semi-arid central Washington is relatively well popu- lated, and there are likely to be people who have observed the storms. Such witnesses …

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Volumes And Areas Of Early Weichselian Ice Dammed Lakes In Northern Russia, Martin Jakobsson, Jan Mangerud, Valery Astakov, John Inge Svendsen Dec 2001

Volumes And Areas Of Early Weichselian Ice Dammed Lakes In Northern Russia, Martin Jakobsson, Jan Mangerud, Valery Astakov, John Inge Svendsen

Center for Coastal and Ocean Mapping

No abstract provided.

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Harmonising Chart And Navigation-Related Information On Ecdis, Lee Alexander Dec 2001

Harmonising Chart And Navigation-Related Information On Ecdis, Lee Alexander

Center for Coastal and Ocean Mapping

ECDIS is a real-time navigation system that integrates a variety of chart and navigation-related information. More than simply a replacement for a paper nautical chart, ECDIS is capable of continuously determining a vessel's position in relation to land, charted objects, aids-to-navigation, and unseen hazards. Increasingly, ECDIS is being used for both navigation and collision-avoidance tasks. There is growing concern about the display of ever-increasing amounts of both chart and navigation-related information. When it comes to using ECDIS, displaying more information is not necessarily better. Too much information (i.e., clutter) may only lead to confusion. In this regard, there is need …

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One-Gas Models With Height-Dependent Mean Molecular Weight: Effects On Gravity Wave Propagation, R. L. Walterscheid, Michael P. Hickey Ph.D. Dec 2001

One-Gas Models With Height-Dependent Mean Molecular Weight: Effects On Gravity Wave Propagation, R. L. Walterscheid, Michael P. Hickey Ph.D.

Publications

Many models of the thermosphere employ the one-gas approximation where the governing equations apply only to the total gas and the physical properties of the gas that depend on composition (mean molecular weight and specific heats) are height-dependent. It is further assumed that the physical properties of the gas are locally constant; thus motion-induced perturbations are nil. However, motion in a diffusively separated atmosphere perturbs local values of mean molecular weight and specific heats. These motion-induced changes are opposed by mutual diffusion of the constituent gases, which attempts to restore diffusive equilibrium. Assuming that composition is locally constant is equivalent …

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Relationships Between Oceanographic Satellite Data And Alexandrium Distributions In The Gulf Of Maine, Remy Martin Luerssen Dec 2001

Relationships Between Oceanographic Satellite Data And Alexandrium Distributions In The Gulf Of Maine, Remy Martin Luerssen

Electronic Theses and Dissertations

An examination is made of the qualitative and quantitative relationships between satellite derived sea-surface temperature (SST) and chlorophyll patterns and the distribution of Alexandrium, the toxic dinoflagellate species responsible for HABs in the GOM. Daily images coincident with five ECOHAB survey cruises in 1998 and 2000 are composited over each cruise period to create mean patterns for each sample period. Contours of surface Alexandrium cell concentrations are superimposed on the images as well as images showing the strength and location of SST frontal zones to examine qualitative relationships. Results indicate that high concentrations of Alexandrium are located primarily in the …

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Dark Production: A Significant Source Of Oceanic Cos, M. Von Hobe, Gregory A. Cutter, A. J. Kettle, M. O. Andreae Dec 2001

Dark Production: A Significant Source Of Oceanic Cos, M. Von Hobe, Gregory A. Cutter, A. J. Kettle, M. O. Andreae

OES Faculty Publications

Carbonyl sulfide (COS) in air and dissolved in seawater was determined during a cruise in August 1999 in the Sargasso Sea in the northwest Atlantic Ocean. Dissolved concentrations at the sea surface displayed only a weak diel cycle with a mean of 8.6 ± 2.8 pmol dm−3 owing to low abundance of photochemical precursors and high temperatures causing rapid hydrolysis. Depth profiles measured over the oceanic mixed layer revealed significant vertical gradients of COS concentration with higher values at the surface, suggesting that the rate of photochemical production at the surface exceeds the rate of vertical mixing. The mean …

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Three Dimensional Hydrodynamic Modeling Study, Craney Island Eastward Expansion, Lower James River And Elizabeth River, Virginia, Harry V. Wang, S. C. Kim, John D. Boon, A. Y. Kuo, G. M. Sisson, J. M. Brubaker, J. P-Y. Maa Dec 2001

Three Dimensional Hydrodynamic Modeling Study, Craney Island Eastward Expansion, Lower James River And Elizabeth River, Virginia, Harry V. Wang, S. C. Kim, John D. Boon, A. Y. Kuo, G. M. Sisson, J. M. Brubaker, J. P-Y. Maa

Reports

The Craney Island Eastward Expansion Hydrodynamic Model Study was conducted in three phases: 1) model calibration and verification for the Elizabeth River, 2) model testing of four Craney Island expansion options using single variable runs (using a single variable, tidal range, for model input), 3) model testing of two expansion options using historical runs (using multiple variables in real time for model input). The expansion option designs were evaluated for both global and local hydrodynamic change through simulation comparisons with the Base Case condition.

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Gametogenic Cycles Of Marine Mussels, Mytilus Edulis And Mytilus Trossulus, In Cobscook Bay, Maine, Aaron P. Maloy Dec 2001

Gametogenic Cycles Of Marine Mussels, Mytilus Edulis And Mytilus Trossulus, In Cobscook Bay, Maine, Aaron P. Maloy

Electronic Theses and Dissertations

The Mytilus edulis species complex includes three smooth-shelled blue mussels, M. edulis (Linnaeus 1 75 8), M trossulus (Gould 1 850), and M galloprovincialis (Lamarck 18 19). When any two of theses species occur sympatrically, hybridization and backcrossing of hybrid and parental genotypes is evident. Despite introgression of genes between taxa their genetic integrity is maintained. To test the hypothesis that a temporal variation in species-specific spawning times is the mechanism limiting hybridization and maintaining genetic integrity in a M edulis and M. trossulus hybrid zone in eastern Maine, mussels were sampled on monthly to semi-monthly intervals throughout 2000 from …

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The Effects Of Temperature On The Survival, Growth And Development Of Larvae Of Two Blue Mussel Species (Mytilus Edulis And Mytilus Trossulus), Susan Hayhurst Dec 2001

The Effects Of Temperature On The Survival, Growth And Development Of Larvae Of Two Blue Mussel Species (Mytilus Edulis And Mytilus Trossulus), Susan Hayhurst

Electronic Theses and Dissertations

Factors affecting the distribution of Mytilus edulis and Mytilus trossulus in the Gulf of Maine are of great interest because of the blue mussel's economic and ecological importance. Genetic surveys of blue mussel populations indicate that eastern Maine represents the southern distributional limit for M. trossulus but that M. edulis is common throughout the Gulf of Maine. Because hydrographic features in the Gulf of Maine confound temperature variation and larval dispersal patterns, the relative importance of these potential range-limiting mechanisms cannot be ascertained from the distribution of adult mussels. Given that larvae are more vulnerable than adults to temperature extremes, …

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The Role Of Water Motion In Algal Reproduction, Richard Gordon Dec 2001

The Role Of Water Motion In Algal Reproduction, Richard Gordon

Electronic Theses and Dissertations

Environmental conditions, such as water motion, can influence fertilization success and spore dispersal in marine algae. Previous studies on fucoid algae showed that gamete release is restricted to, or enhanced by, periods of low water motion. Few other algal taxa have been investigated, however, including species with an alternation of generations. I investigated gamete and spore release in the macroalgae Alaria esculenta and Ulva lactuca, as well as in the diatom Pseudo-nitachia multiseries to determine if water motion is inhibitory or stimulates propagule production and release. I used orbital shakers to simulate water motion; these were interspersed with stationary platforms …

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Uwit: Underwater Image Toolbox And Mosaicking In Matlab, R. Eustice, O. Pizarro, C. Roman, H. Singh Nov 2001

Uwit: Underwater Image Toolbox And Mosaicking In Matlab, R. Eustice, O. Pizarro, C. Roman, H. Singh

Christopher N. Roman

No abstract provided.

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A Short Summary Of Seabed And Some Data Highlights, H. Singh, R. Eustice, C. Roman, O. Pizarro, N. Mcphee Nov 2001

A Short Summary Of Seabed And Some Data Highlights, H. Singh, R. Eustice, C. Roman, O. Pizarro, N. Mcphee

Christopher N. Roman

No abstract provided.

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High-Precision Dating Of Volcanic Events (A.D. 1301–1995) Using Ice Cores From Law Dome, Antarctica, Anne S. Palmer, Tas D. Van Ommen, Mark A. J. Curran, Vin Morgan, Joe M. Souney, Paul Andrew Mayewski Nov 2001

High-Precision Dating Of Volcanic Events (A.D. 1301–1995) Using Ice Cores From Law Dome, Antarctica, Anne S. Palmer, Tas D. Van Ommen, Mark A. J. Curran, Vin Morgan, Joe M. Souney, Paul Andrew Mayewski

Earth Science Faculty Scholarship

A record of volcanic activity over the period A.D. 1301–1995 has been extracted from three Law Dome ice cores (East Antarctica). The record dating is unambiguous at the annual level from A.D. 1807 to 1995 and has an uncertainty of ±1 year at A.D. 1301. Signals from 20 eruptions are preserved in the record, including those of two unknown eruptions with acid deposition beginning in A.D. 1810.8 and A.D. 1685.8. The beginning of the ice core signal from the A.D. 1815 Tambora eruption is observed in the austral summer of A.D. 1816/1817. The mean observed stratospheric transport and deposition time …

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Reflection Of A Long-Period Gravity Wave Observed In The Nightglow Over Arecibo On May 8–9, 1989?, Michael P. Hickey Ph.D. Nov 2001

Reflection Of A Long-Period Gravity Wave Observed In The Nightglow Over Arecibo On May 8–9, 1989?, Michael P. Hickey Ph.D.

Publications

During the Arecibo Initiative for Dynamics of the Atmosphere (AIDA) campaign in 1989 a characteristic of gravity wave perturbations observed in mesopause region airglow emissions was that airglow brightness fluctuations and airglow-derived temperature fluctuations often occurred either in phase or in antiphase. This stimulated the development of a theory suggesting that such in-phase fluctuations were most probably the result of strong reflections occurring in the mesosphere and lower thermosphere region. Recent examination of a particular wave event and application of simple WKB-type theory has appeared to support this hypothesis. Here we use a full-wave model and a WKB-type model, each …

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Hypsometry And Volume Of The Arctic Ocean And Its Constituent's Seas, Martin Jakobsson Nov 2001

Hypsometry And Volume Of The Arctic Ocean And Its Constituent's Seas, Martin Jakobsson

Center for Coastal and Ocean Mapping

No abstract provided.

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Ecdis Development Laboratory And Navigation Technology Demonstration Center, Lee Alexander, Maxim F. Van Norden, Charles M. Fralick Nov 2001

Ecdis Development Laboratory And Navigation Technology Demonstration Center, Lee Alexander, Maxim F. Van Norden, Charles M. Fralick

Center for Coastal and Ocean Mapping

The U.S. Navy is undergoing a major transition from traditional, paper chart navigation to computer-based electronic charting. The Chief of Naval Operations (CNO) has mandated that all Navy ships will navigate strictly through electronic means by FY07. However, due to some recent groundings, the Navy is now striving to accelerate the full implementation of electronic navigation by FY04. The Naval Oceanographic Office (NAVOCEANO) is making a concerted effort to support this transition with upgrades to state-of-the-art survey ships, instrumentation, and data processing equipment. NAVOCEANO is increasing its capability to rapidly collect and process hydrographic survey data, and to quickly produce …

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Field Evaluation Of Sounding Accuracy In Deep Water Multibeam Swath Bathymetry, Christian De Moustier Nov 2001

Field Evaluation Of Sounding Accuracy In Deep Water Multibeam Swath Bathymetry, Christian De Moustier

Center for Coastal and Ocean Mapping

A new Kongsberg-Simrad EM120 multibeam echo-sounder has been installed aboard Scripps Institution of Oceanography's Research Vessel Roger Revelle in January 2001. This system can map reliably a 20 km swath of seafloor in 4000 m water depth with 191 soundings per ping. Such a wide swath width demands highly accurate (<0.05' RMS) roll information from a motion sensor, and makes estimating sounding accuracy across the swath an interesting challenge. It is shown that good accuracy estimates can be obtained by collecting data on station under control of the GPS-aided dynamic positioning system usually available on most modern long-range oceanographic vessels. A number of motion sensors, with RMS roll accuracy specifications ranging from 0.05' to 0.01' ,were tested with the EM120 sonar on station in 3800 m to 4000 m water depths. Unexpectedly, they yielded roughly the same depth uncertainty as a function of receive beam angle. This result might be explained by synchronization errors between the attitude data and the sonar data leading to beam pointing errors, other types of beam pointing errors, a range of roll accuracy narrower than specified for the motion sensors, or a combination of these factors

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Geozui3d: Data Fusion For Interpreting Oceanographic Data, Colin Ware, Matthew D. Plumlee, Roland J. Arsenault, Larry A. Mayer, Shep M. Smith Lt, Donald H. House Nov 2001

Geozui3d: Data Fusion For Interpreting Oceanographic Data, Colin Ware, Matthew D. Plumlee, Roland J. Arsenault, Larry A. Mayer, Shep M. Smith Lt, Donald H. House

Center for Coastal and Ocean Mapping

GeoZui3D stands for Geographic Zooming User Interface. It is a new visualization software system designed for interpreting multiple sources of 3D data. The system supports gridded terrain models, triangular meshes, curtain plots, and a number of other display objects. A novel center of workspace interaction method unifies a number of aspects of the interface. It creates a simple viewpoint control method, it helps link multiple views, and is ideal for stereoscopic viewing. GeoZui3D has a number of features to support real-time input. Through a CORBA interface external entities can influence the position and state of objects in the display. Extra …

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Estimation Of Error In Large Area Underwater Photomosaics Using Vehicle Navigation Data, C. Roman, H. Singh Oct 2001

Estimation Of Error In Large Area Underwater Photomosaics Using Vehicle Navigation Data, C. Roman, H. Singh

Christopher N. Roman

Creating geometrically accurate photomosaics of underwater sites using images collected from an AUV or ROV is a difficult task due to dimensional errors which grow as a function of 3D image distortion and the mosaicking process. Although photomosiacs are accurate locally their utility for accurately representing a large survey area is jeopardized by this error growth. Evaluating the error in a mosaic is the first step in creating globally accurate photomosaics of an unstructured environment with bounded error. Using vehicle navigation data and sensor offsets it is possible to estimate the error present in large area photomosaics independent of the …

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Seawater Temperature Trends At Usa Tide Gauge Sites, George A. Maul, Andria M. Davis, Jeffrey W. Simmons Oct 2001

Seawater Temperature Trends At Usa Tide Gauge Sites, George A. Maul, Andria M. Davis, Jeffrey W. Simmons

Ocean Engineering and Marine Sciences Faculty Publications

Seawater temperatures have been measured at United States tide gauges throughout most of the 20th century. All available records have been digitized, and the longest 14 have been analyzed by linear least-square regression. The largest positive trend is from Boston MA (+3.6 ± 0.4°C per century), and the largest negative trend is at Charleston SC (-0.1 ± 0.3°C per century). No consistent latitudinal or eastcoast vs. west-coast patterns are discernable, but air temperature trends are typically greater than seawater changes.

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The Origin Of A Polar Ice Sheet In East Antarctica, George H. Denton Oct 2001

The Origin Of A Polar Ice Sheet In East Antarctica, George H. Denton

University of Maine Office of Research Administration: Grant Reports

This award supports a study to determine the sequence and chronology of events that led to the development of the Antarctic ice sheet. A continental-scale ice sheet probably first developed in East Antarctica close to the Eocene-Oligocene boundary under temperate climatic conditions. The purpose of this project is to determine, from landscape analysis (with a numerical chronology), when (and why) these early temperate conditions gave way to a polar environment in Antarctica. From previous field work and recent photographic analysis, an extensive relict landscape (older than 17 million years) with landforms and erosional features characteristic of temperate glaciation has been …

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Poor Water Resources And Drought In The Gujarat/Saurashtra Regions Of India, K. K. Nathan Oct 2001

Poor Water Resources And Drought In The Gujarat/Saurashtra Regions Of India, K. K. Nathan

Drought Network News (1994-2001)

Inadequate water resources pose a big threat to the economy, human activities, and livelihood in the Gujarat/Saurashtra regions of India. Scanty rainfall with wide aberrations in its distribution has made the situation worse, leading to chronic drought in the state in 2001. With the exception of the Narmada and Tapi rivers, there are hardly any water resources to sustain agricultural production in the region. The gradual disappearance of forest cover in the state has further aggravated the drought situation. This has led to large-scale erosion of the topsoil, particularly near the riverside. There is apprehension that the region will soon …

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Creating A Network Of Regional Drought Preparedness Networks: A Call For Action, Donald A. Wilhite Oct 2001

Creating A Network Of Regional Drought Preparedness Networks: A Call For Action, Donald A. Wilhite

Drought Network News (1994-2001)

Drought is a creeping, slow-onset natural hazard that is a normal part of climate for virtually all regions of the world; it results in serious economic, social, and environmental impacts. Its onset and end are often difficult to determine, as is its severity. Drought affects more people than any other natural hazard. Lessons from developed and developing countries demonstrate that drought results in significant impacts, regardless of level of development, although the character of these impacts will differ profoundly. At the Meeting on Opportunities for Sustainable Investment in Rainfed Areas of West Asia and North Africa (WANA), held in June …

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Derivation Of Del180 From Sediment Core Log Data' Implications For Millennial-Scale Climate Change In The Labrador Sea, M. E. Weber, Larry A. Mayer, C. Hillaire-Marcel, G. Bilodeau, F. Rack, R. N. Hiscott, A. E. Aksu Oct 2001

Derivation Of Del180 From Sediment Core Log Data' Implications For Millennial-Scale Climate Change In The Labrador Sea, M. E. Weber, Larry A. Mayer, C. Hillaire-Marcel, G. Bilodeau, F. Rack, R. N. Hiscott, A. E. Aksu

Center for Coastal and Ocean Mapping

Sediment core logs from six sediment cores in the Labrador Sea show millennial-scale climate variability during the last glacial by recording all Heinrich events and several major Dansgaard-Oeschger cycles. The same millennial-scale climate change is documented for surface water δ18O records of Neogloboquadrina pachyderma (left coiled); hence the surface water δ18O record can be derived from sediment core logging by means of multiple linear regression, providing a paleoclimate proxy record at very high temporal resolution (70 years). For the Labrador Sea, sediment core logs contain important information about deepwater current velocities and also reflect the variable …

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Sensor-Assisted Video Mosaicing For Seafloor Mapping, Yuri Rzhanov, Randy G. Cutter Jr., Lloyd C. Huff Oct 2001

Sensor-Assisted Video Mosaicing For Seafloor Mapping, Yuri Rzhanov, Randy G. Cutter Jr., Lloyd C. Huff

Center for Coastal and Ocean Mapping

This paper discusses a proposed processing technique for combining video imagery with auxiliary sensor information. The latter greatly simplifies image processing by reducing complexity of the transformation model. The mosaics produced by this technique are adequate for many applications, in particular habitat mapping. The algorithm is demonstrated through simulations and hardware configuration is described.

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Observations Of Persistent Leonid Meteor Trails 2. Photometry And Numerical Modeling, C. A. Kruschwitz, M. C. Kelley, C. S. Gardner, G. Swenson, A. Z. Liu, X. Chu, J. D. Drummond, B. W. Grime, W. T. Armstrong, J. M. C. Plane, P. Jenniskens Oct 2001

Observations Of Persistent Leonid Meteor Trails 2. Photometry And Numerical Modeling, C. A. Kruschwitz, M. C. Kelley, C. S. Gardner, G. Swenson, A. Z. Liu, X. Chu, J. D. Drummond, B. W. Grime, W. T. Armstrong, J. M. C. Plane, P. Jenniskens

Physical Sciences - Daytona Beach

During the 1998 Leonid meteor shower, multi-instrument observations of persistent meteor trains were made from the Starfire Optical Range on Kirtland Air Force Base, New Mexico, and from a secondary site in nearby Placitas, New Mexico. The University of Illinois Na resonance lidar measured the Na density and temperature in the trains, while various cameras captured images and videos of the trains, some of which were observed to persist for more than 30 min. The Na density measurements allow the contribution of Na airglow to the observed train luminescence to be quantified for the first time. To do this, persistent …

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Illinois River 2000 Pollutant Loads At Arkansas 59 Bridge, Marc A. Nelson, Thomas S. Soerens Oct 2001

Illinois River 2000 Pollutant Loads At Arkansas 59 Bridge, Marc A. Nelson, Thomas S. Soerens

Technical Reports

Automatic water samplers and a U. S. Geological Survey gauging station were established in 1995 on the main stem of the Illinois River at the Arkansas Highway 59 Bridge. Since that time, continuous stage and discharge measurements and water quality sampling have been used to determine pollutant concentrations and loads in the Arkansas portion of the Illinois River. This report represents the results from the measurement and sampling for January 1, 2000 to December 31, 2000

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Fall 2001, Nsu Oceanographic Center Oct 2001

Fall 2001, Nsu Oceanographic Center

Currents

No abstract provided.

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