Science.gov

Sample records for ocean environment based

  1. Model-Based Detection in a Shallow Water Ocean Environment

    SciTech Connect

    Candy, J V

    2001-07-30

    A model-based detector is developed to process shallow water ocean acoustic data. The function of the detector is to adaptively monitor the environment and decide whether or not a change from normal has occurred. Here we develop a processor incorporating both a normal-mode ocean acoustic model and a vertical hydrophone array. The detector is applied to data acquired from the Hudson Canyon experiments at various ranges and its performance is evaluated.

  2. Broadband model-based processing for shallow ocean environments

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1998-07-01

    Most acoustic sources found in the ocean environment are spatially complex and broadband. In the case of shallow water propagation, these source characteristics complicate the analysis of received acoustic data considerably. A common approach to the broadband problem is to decompose the received signal into a set of narrow-band lines. This then allows the problem to be treated as a multiplicity of narrow-band problems. Here a model-based approach is developed for the processing of data received on a vertical array from a broadband source where it is assumed that the propagation is governed by the normal-mode model. The goal of the processor is to provide an enhanced (filtered) version of the pressure at the array and the modal functions. Thus a pre-processor is actually developed, since one could think of several applications for these enhanced quantities such as localization, modal estimation, etc. It is well-known that in normal-mode theory a different modal structure evolves for each temporal frequency; thus it is not surprising that the model-based solution to this problem results in a scheme that requires a {open_quotes}bank{close_quotes} of narrow-band model-based processors{emdash}each with its own underlying modal structure for the narrow frequency band it operates over. The {open_quotes}optimal{close_quotes} Bayesian solution to the broadband pressure field enhancement and modal function extraction problem is developed. It is shown how this broadband processor can be implemented (using a suboptimal scheme) in pseudo real time due to its inherent parallel structure. A set of noisy broadband data is synthesized to demonstrate how to construct the processor and achieve a minimum variance (optimal Bayesian) design. It is shown that both broadband pressure-field and modal function estimates can be extracted illustrating the feasibility of this approach. {copyright} {ital 1998 Acoustical Society of America.}

  3. Sequential Model-Based Detection in a Shallow Ocean Acoustic Environment

    SciTech Connect

    Candy, J V

    2002-03-26

    A model-based detection scheme is developed to passively monitor an ocean acoustic environment along with its associated variations. The technique employs an embedded model-based processor and a reference model in a sequential likelihood detection scheme. The monitor is therefore called a sequential reference detector. The underlying theory for the design is developed and discussed in detail.

  4. Monitoring the Ocean Acoustic Environment: A Model-Based Detection Approach

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    2000-03-13

    A model-based approach is applied in the development of a processor designed to passively monitor an ocean acoustic environment along with its associated variations. The technique employs an adaptive, model-based processor embedded in a sequential likelihood detection scheme. The trade-off between state-based and innovations-based monitor designs is discussed, conceptually. The underlying theory for the innovations-based design is briefly developed and applied to a simulated data set.

  5. Model-based processing for shallow ocean environments: The broadband problem

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1996-01-31

    Most acoustic sources found is the ocean environmental are spatially complex and broadband. When propagating in a shallow ocean these source characteristics complicate the analysis of received acoustic data considerably. The enhancement of broadband acoustic pressure- field measurements using a vertical array is discussed. Here a model- based approach is developed for a broadband source using a normal- mode propagation model.

  6. Supporting Teachers' Use of a Project-Based Learning Environment in Ocean Science: Web-Based Educative Curriculum Materials

    ERIC Educational Resources Information Center

    Duncan, Ravit Golan; El-Moslimany, Hebbah; McDonnell, Janice; Lichtenwalner, Sage

    2011-01-01

    The development of inquiry and project-based materials is challenging in many ways, not the least of which is the design of supports for teachers implementing such materials. We report on the design of educative and just-in-time teacher supports for an online project-based unit in ocean science. The teacher supports were visible as tabs on the…

  7. Connections: Ocean Environments. Unit Grade 5.

    ERIC Educational Resources Information Center

    Ney, Catherine R.

    Ocean Environments for Grade 5 is a 12-week interdisciplinary ocean environmental unit designed for teachers to use with their students. The unit emphasizes investigation and understanding of our ocean environments, including their geological, physical, and biological characteristics. It also stresses awareness of public policy decisions related…

  8. Broadband acoustic source processing in a noisy shallow ocean environment

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1996-07-18

    Acoustic sources found in the ocean environment are spatially complex and broadband, complicating the analysis of received acoustic data considerably. A model-based approach is developed for a broadband source in a shallow ocean environment characterized by a normal-mode propagation model. Here we develop the optimal Bayesian solution to the broadband pressure-field enhancement and modal function extraction problem.

  9. Predicting the Arctic Ocean Environment in the 21st century

    NASA Astrophysics Data System (ADS)

    Aksenov, Yevgeny; Popova, Ekaterina; Yool, Andrew; Nurser, George

    2015-04-01

    Recent environmental changes in the Arctic have clearly demonstrated that climate change is faster and more vigorously in the Polar Regions than anywhere else. Significantly, change in the Arctic Ocean (AO) environment presents a variety of impacts, from ecological to social-economic and political. Mitigation of this change and adaptation to it requires detailed and robust environmental predictions. Here we present a detailed projection of ocean circulation and sea ice from the present until 2099, based on an eddy-permitting high-resolution global simulation of the NEMO ¼ degree ocean model. The model is forced at the surface with HadGEM2-ES atmosphere model output from the UK Met. Office IPCC Assessment Report 5 (AR5) Representative Concentration Pathways 8.5 (RCP8.5) scenario. The HadGEM2-ES simulations span 1860-2099 and are one of an ensemble of runs performed for the Coupled Model Intercomparison Project 5 (CMIP5) and IPCC AR5. Between 2000-2009 and 2090-2099 the AO experiences a significant warming, with sea surface temperature increasing on average by about 4° C, particularly in the Barents and Kara Seas, and in the Greenland Sea and Hudson Bay. By the end of the simulation, Arctic sea ice has an average annual thickness of less than 10 cm in the central AO, and less than 0.5 m in the East-Siberian Sea and Canadian Archipelago, and disappears entirely during the Arctic summer. In summer, opening of large areas of the Arctic Ocean to the wind and surface waves leads to the Arctic pack ice cover evolving into the Marginal Ice Zone (MIZ). In winter, sea ice persists until the 2030s; then it sharply declines and disappears from the Central Arctic Ocean by the end of the 21st century, with MIZ provinces remaining in winter along the Siberian, Alaskan coasts and in the Canadian Arctic Archipelago. Analysis of the AO circulation reveals evidence of (i) the reversal of the Arctic boundary currents in the Canadian Basin, from a weak cyclonic current in 2040-2049 to

  10. Model-based ocean acoustic passive localization

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1994-01-24

    The detection, localization and classification of acoustic sources (targets) in a hostile ocean environment is a difficult problem -- especially in light of the improved design of modern submarines and the continual improvement in quieting technology. Further the advent of more and more diesel-powered vessels makes the detection problem even more formidable than ever before. It has recently been recognized that the incorporation of a mathematical model that accurately represents the phenomenology under investigation can vastly improve the performance of any processor, assuming, of course, that the model is accurate. Therefore, it is necessary to incorporate more knowledge about the ocean environment into detection and localization algorithms in order to enhance the overall signal-to-noise ratios and improve performance. An alternative methodology to matched-field/matched-mode processing is the so-called model-based processor which is based on a state-space representation of the normal-mode propagation model. If state-space solutions can be accomplished, then many of the current ocean acoustic processing problems can be analyzed and solved using this framework to analyze performance results based on firm statistical and system theoretic grounds. The model-based approach, is (simply) ``incorporating mathematical models of both physical phenomenology and the measurement processes including noise into the processor to extract the desired information.`` In this application, we seek techniques to incorporate the: (1) ocean acoustic propagation model; (2) sensor array measurement model; and (3) noise models (ambient, shipping, surface and measurement) into a processor to solve the associated localization/detection problems.

  11. Oceanic satellite data service system based on web

    NASA Astrophysics Data System (ADS)

    Kang, Yan; Pan, Delu; He, Xianqiang; Wang, Difeng; Chen, Jianyu; Chen, Xiaoyan

    2011-11-01

    The ocean satellite observation is more and more important to study the global change, protect ocean resource and implement ocean engineering for their large area cover and high frequency observation, which have already given us a global view of ocean environment parameters, including the sea surface temperature, ocean color, wind, wave, sea level and sea ice, etc... China has made great progress in ocean environment remote sensing over the last couple of years. These data are widely used for a variety of applications in ocean environment studies, coastal water quality monitoring environmental, fishery resources protection, development and utilization of fishery resources, coastal engineering and oceanography. But the data are no online information access and dissemination, no online visualization & browsing, no online query and analyze capability. To facilitate the application of the data and to help disseminating the data, a web-service system has developed. The system provides capabilities of online oceanic satellite information access, query, visualize and analyze. It disseminates oceanic satellite data to the users via real time retrieval, processing and publishing through standards-based geospatial web services. A region of interest can also be exported directly to Google Earth for displaying or downloaded. This web service system greatly improves accessibility, interoperability, usability, and visualization of oceanic satellite data without any client-side software installation.

  12. Nitrogen recycling efficiency in steady-state oceanic environments

    NASA Astrophysics Data System (ADS)

    King, Frederick D.

    1987-06-01

    Nitrogen recycling in oceanic environments is considered on a cost to benefit basis; recycling efficiency ( R) defines the ratio of total heterotrophic nitrogen regeneration to the rate of phytoplankton grazed. A simple model is derived which demonstrates that R is a function of the excretion to ingestion ratios of organisms at each trophic level as well as the length of the food chain. R is discussed in relation to ecological efficiency, and model equations are solved for relative production, regeneration and egestion for 1-5 trophic levels using an ecological efficiency characteristic of an oceanic environment. Analysis of the microbial loop on the basis of recycling efficiency indicates that marine microheterotrophs may not contribute as much to nitrogen regeneration as previously suggested. Finally, the ecological role of nitrogen recycling is discussed in relation to the maintenance of nutrient-sufficient relatively high growing algal populations in oceanic waters depleted of inorganic nitrogen.

  13. Non-deterministic analysis of ocean environment loads

    SciTech Connect

    Fang Huacan; Xu Fayan; Gao Guohua; Xu Xingping

    1995-12-31

    Ocean environment loads consist of the wind force, sea wave force etc. Sea wave force not only has randomness, but also has fuzziness. Hence the non-deterministic description of wave environment must be carried out, in designing of an offshore structure or evaluation of the safety of offshore structure members in service. In order to consider the randomness of sea wave, the wind speed single parameter sea wave spectrum is proposed in the paper. And a new fuzzy grading statistic method for considering fuzziness of sea wave height H and period T is given in this paper. The principle and process of calculating fuzzy random sea wave spectrum will be published lastly.

  14. Optimal Localization of Ocean Acoustic Sources in AN Uncertain Environment

    NASA Astrophysics Data System (ADS)

    Richardson, Anthony Merle

    1990-01-01

    In this paper, a method for determining the position of an underwater acoustic source from observations of the associated acoustic field and information about the acoustic environment is presented. This algorithm, unlike matched field processing algorithms, does not require complete knowledge of the acoustic environment, but can determine source position even with uncertain or imprecise information about the environment. The algorithm is termed the optimum uncertain field processing algorithm. Parameter estimation theory is utilized to derive the new algorithm. This provides a systematic, optimal approach to the problem, and allows environmental uncertainty to be easily incorporated into the algorithm. In addition to estimating source position, estimates of parameters of the acoustic environment can also be calculated. This makes simultaneous source localization and acoustic tomographic estimation of ocean parameters possible. A detailed discussion of the acoustic propagation models used in the research is presented. The defining equation for the optimum uncertain field processor is then derived. It is shown that the algorithm reduces to a popular matched field processing technique for the special case in which the environment is completely known. A series of studies that illustrate the robust performance of the uncertain field processor, relative to the performance of matched field processing methods, is made. Estimation of ocean acoustic parameters is also illustrated. The affects of environmental uncertainty, source position, and frequency on localization performance are examined.

  15. Paludification and Forest Retreat in Northern Oceanic Environments

    PubMed Central

    CRAWFORD, R. M. M.; JEFFREE, C. E.; REES, W. G.

    2003-01-01

    Examination of temperature variations over the past century for Europe and the Arctic from northern Norway to Siberia suggests that variations in the North Atlantic Oscillation are associated with an increase in oceanicity in certain maritime regions. A southward depression of the treeline in favour of wet heaths, bogs and wetland tundra communities is also observed in northern oceanic environments. The physiological basis for this change in ecological succession from forest to bog is discussed in relation to the long‐term effects of flooding on tree survival. The heightened values currently detected in the North Atlantic Oscillation Index, together with rising winter temperatures, and increased rainfall in many areas in northern Europe, presents an increasing risk of paludification with adverse consequences for forest regeneration, particularly in areas with oceanic climates. Climatic warming in oceanic areas may increase the area covered by bogs and, contrary to general expectations, lead to a retreat rather than an advance in the northern limit of the boreal forest. High water‐table levels are not automatically detrimental to forest survival as can be seen in swamp, bottomland and mangrove forests. Consequently, the inhibitory effects of flooding on tree survival and regeneration in northern regions should not be uncritically accepted as merely due to high water levels. Evidence is discussed which suggests that physiological and ecological factors may interact to inhibit forest regeneration in habitats where there is a risk of prolonged winter‐flooding combined with warmer winters and cool moist summers. PMID:12509342

  16. Fiber Optic Cables in a Harsh Ocean Environment

    NASA Astrophysics Data System (ADS)

    Glavas, Xenophon G.

    1987-02-01

    Fiber optic cables have found widespread use in the ocean, but to fulfill its mission the cable must survive deployment and operation scenarios. Preservation of the manufactured strength and the optical transmission capacity of the optical fiber over its application lifetime are the primary system objectives. Other secondary objectives defined by system requirements include: fiber count, flexibility, weight, strength, lifetime, manufacturability, diameter, specific gravity, torsion stiffness, temperature influence, pressure effects, abrasion, cyclic flexure resistance, to name a few. This paper will discuss fiber optic cables, causes of failures, and their materials for use in the ocean for three general classes: a. Low cost, disposable cables. This requires the replacement rather than the repair of subject cables. Several applications fall into this category namely torpedo guidance, rapidly dispensible acoustic systems, and sonobuoy links. Life expectancy is months. b. Moderate cost, replaceable cables. This class of cables also requires the replacement of the cable; however, the system lifetime requires the cable be manufactured with the best materials for ocean service so once it is deployed, survival is ensured for many months or even years. Once the cable has failed, there will be no attempt to repair or recover the product, only replace it. Again, this type of cable would see an environment that spans the ocean depths. c. High cost, repairable cables. This class of cables constitutes the family of cables that generally require many years of service, extremely high cable bandwidth (high fiber count), span the major ocean depths and service continents or nations for their communications needs. The starting point for any cable design is defining the requirements the cable must meet. A systems approach is used to derive and impose on the design those requirements that influence cable function, life, cost and transmission capacity. A system analyses defines the

  17. Particles in the oceans: Implication for a safe marine environment.

    PubMed

    Blasco, Julian; Corsi, Ilaria; Matranga, Valeria

    2015-10-01

    Strategies and technologies for the ecosafety assessment and design of engineered particles entering the marine environment are urgently needed. As the application of nanoparticles in science and technology grows, the need to understand their impact on the marine environment becomes increasingly important. This Editorial introduces a Special Issue on the topic of a sustainable and safety use of nanoparticles for protecting, recovering and supporting the oceans' environment and consequently human health. The issue focus on the impact of micro/nano-plastics and metallic nanoparticles on marine organisms, as well as some methodological aspects associated to the eco/toxicity and analytical approaches for in deep physico-chemical characterization of nanoparticles in marine waters and sediment media. Important and urgent topics are addressed in the field of nano-ecosafety in order to assess more precisely both exposure routes and environmental hazards of nanoparticles in the ocean. Ecotoxicological and toxicological data, obtained using a wide variety of organisms representative of different trophic levels and biological organization, from whole animals to macromolecules, will be useful for a better definition of cleaner and safer nanoparticles. Efforts in developing a broad understanding of target species, expected results, benchmarks and timelines, will be of primary importance. PMID:26515473

  18. Marine-acquired infections. Hazards of the ocean environment.

    PubMed

    Chang, W J; Pien, F D

    1986-09-15

    Numerous pathogenic bacteria are found in seawater. They can cause several environmental infections, such as conjunctivitis, otitis externa, wound infections, pneumonia, and gastrointestinal illness. The incidence of some of these infections could be lowered if people took care to avoid eating undercooked seafood, swimming in brackish water, or sustaining lacerations in a marine environment. However, such infections will probably increase in frequency as more people visit ocean resorts. Prompt elimination of the infective agent, adequate wound care, and avoidance of reexposure can minimize the severity of the condition. PMID:3763516

  19. Radioactive pollution: Ocean environments. (Latest citations from Oceanic abstracts). Published Search

    SciTech Connect

    Not Available

    1994-04-01

    This bibliography contains citations concerning radioactive pollution of the marine environment. Distrubutions of radionuclides that indicate artificial radioactive contamination are discussed including iodine-131, various uranium isotopes, Cesium-137, Cobalt-60, Strontium-90, Ruthenium-160, and plutonium isotopes. Ecosystems considered include coral reefs and atolls, planktonic zones in the open ocean, salt marshes, estuaries, coastal waters, and the Mediterranean Sea. Sources of radioactive contamination examined include atomic bomb blasts, fossil fuel combustion, radioactive waste disposal, and nuclear accidents. Experimental simulation of radionuclide transport in marine biota is included. (Contains a minimum of 161 citations and includes a subject term index and title list.)

  20. Radioactive pollution: Ocean environments. (Latest citations from Oceanic abstracts). Published Search

    SciTech Connect

    1997-07-01

    This bibliography contains citations concerning radioactive pollution of the marine environment. Distrubutions of radionuclides that indicate artificial radioactive contamination are discussed including iodine-131, various uranium isotopes, Cesium-137, Cobalt-60, Strontium-90, Ruthenium-160, and plutonium isotopes. Ecosystems considered include coral reefs and atolls, planktonic zones in the open ocean, salt marshes, estuaries, coastal waters, and the Mediterranean Sea. Sources of radioactive contamination examined include atomic bomb blasts, fossil fuel combustion, radioactive waste disposal, and nuclear accidents. Experimental simulation of radionuclide transport in marine biota is included. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  1. Radioactive pollution: Ocean environments. (Latest citations from Oceanic abstracts). Published Search

    SciTech Connect

    1996-05-01

    This bibliography contains citations concerning radioactive pollution of the marine environment. Distrubutions of radionuclides that indicate artificial radioactive contamination are discussed including iodine-131, various uranium isotopes, Cesium-137, Cobalt-60, Strontium-90, Ruthenium-160, and plutonium isotopes. Ecosystems considered include coral reefs and atolls, planktonic zones in the open ocean, salt marshes, estuaries, coastal waters, and the Mediterranean Sea. Sources of radioactive contamination examined include atomic bomb blasts, fossil fuel combustion, radioactive waste disposal, and nuclear accidents. Experimental simulation of radionuclide transport in marine biota is included. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  2. Lidar description of the evaporative duct in ocean environments

    NASA Astrophysics Data System (ADS)

    Willitsford, Adam; Philbrick, C. R.

    2005-08-01

    The description of radar propagation in the presence of the evaporation duct has proven to be a difficult problem in both littoral and open ocean environments. To properly characterize the propagation of a radar beam at low elevation angles, the evaporation duct must be located and scattering properties quantified. The two key elements defining an evaporation duct are the gradients in density and specific humidity. The gradients of the neutral density are determined from the rotational Raman temperature profile. The profile of water vapor is measured directly from the vibrational Raman scattered returns. High spatial resolution and high temporal resolution measurements of water vapor and temperature are required to accurately describe the evaporation duct. Raman lidar techniques can provide these measurements continuously with high accuracy and high resolution so the development of the evaporation duct can be studied. A detailed simulation of a Raman lidar has been developed and applied to a near horizontal path, to examine the expected accuracy for high vertical resolution profiles. The simulation also allows various atmospheric scenarios to be investigated and analyzed. The evaporation duct is an atmospheric phenomenon that causes radar propagation to remain trapped in the surface layer. The duct can be thought of as a waveguide that bends and reflects the radar beam along a path effectively trapping it and guiding it over long distances. This is a major problem for radar propagation paths in both littoral and open ocean environments. Moreover, ducting skews details of radar returns such that radar objects are hidden, or are detected at unexpected distances, or may appear with apparent cross-sections and speeds much different than their actual values.

  3. Microplastics in coastal and marine environments of the western tropical and sub-tropical Atlantic Ocean.

    PubMed

    Costa, Monica F; Barletta, Mário

    2015-11-01

    Microplastic pollution is a global issue. It is present even in remote and pristine coastal and marine environments, likely causing impacts of unknown scale. Microplastics are primary- and secondary-sourced plastics with diameters of 5 mm or less that are either free in the water column or mixed in sandy and muddy sediments. Since the early 1970s, they have been reported to pollute marine environments; recently, concern has increased as soaring amounts of microplastics in the oceans were detected and because the development of unprecedented processes involving this pollutant at sea is being unveiled. Coastal and marine environments of the western tropical and sub-tropical Atlantic Ocean (WTAO) are contaminated with microplastics at different quantities and from a variety of types. The main environmental compartments (water, sediments and biota) are contaminated, but the consequences are still poorly understood. Rivers and all scales of fishery activities are identified as the most likely sources of this pollutant to coastal waters; however, based on the types of microplastics observed, other maritime operations are also possible sources. Ingestion by marine biota occurs in the vertebrate groups (fish, birds, and turtles) in these environments. In addition, the presence of microplastics in plankton samples from different habitats of estuaries and oceanic islands is confirmed. The connectivity among environmental compartments regarding microplastic pollution is a new research frontier in the region. PMID:26457869

  4. Stock assessment and management implications of horse mackerel ( Trachurus japonicus) in Korean waters, based on the relationships between recruitment and the ocean environment

    NASA Astrophysics Data System (ADS)

    Zhang, Chang Ik; Lee, Jae Bong

    This study presents an example of horse mackerel ( Trachurus japonicus) stock to demonstrate that marine environmental factors are important in stock assessment for the new Korean Total Allowable Catch (TAC)-based fisheries management system. The estimated survival rate ( S) of horse mackerel ranged from 0.25 to 0.36. The instantaneous coefficient of natural mortality ( M) was 0.48/year, and the age at first capture was 0.83 year. Annual biomass of horse mackerel in Korean waters was estimated by a biomass-based cohort analysis using annual catch in weight at age during 1965-1995. Yield-per-recruit and spawning biomass-per-recruit were estimated under various harvest strategies at Fmax, F0.1, F30% and F40%. A method for estimating acceptable biological catch (ABC) is proposed for dealing with the large differences in the quality and quantity of information and data available. Using recruitment of horse mackerel estimated from various spawner-recruitment relationship models combined with salinity, volume transport, and zooplankton biomass as environmental factors, the ABC under the best information available was estimated to range from 3100 to 3800 mt.

  5. Model-based inversion for a shallow ocean application

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1994-03-01

    A model-based approach to invert or estimate the sound speed profile (SSP) from noisy pressure-field measurements is discussed. The resulting model-based processor (MBP) is based on the state-space representation of the normal-mode propagation model. Using data obtained from the well-known Hudson Canyon experiment, a noisy shallow water ocean environment, the processor is designed and the results compared to those predicted using various propagation models and data. It is shown that the MBP not only predicts the sound speed quite well, but also is able to simultaneously provide enhanced estimates of both modal and pressure-field measurements which are useful for localization and rapid ocean environmental characterization.

  6. Comparison of aerosol size distribution in coastal and oceanic environments

    NASA Astrophysics Data System (ADS)

    Kusmierczyk-Michulec, Jolanta; van Eijk, Alexander M.

    2006-08-01

    The results of applying the empirical orthogonal functions (EOF) method to decomposition and approximation of aerosol size distributions are presented. A comparison was made for two aerosol data sets, representing coastal and oceanic environments. The first data set includes measurements collected at the Irish Atlantic coast in 1994 and 1995, the second one data collected during the Rough Evaporation Duct (RED) experiment that took place off Oahu, Hawaii in 2001. The main finding is that aerosol size distributions can be represented by a superposition of the mean size distribution and the first eigenvector multiplied by an amplitude function. For the two aerosol data sets the mean size distribution is very similar in the range of small particles sizes (radius < 1μm) but the main difference appears for larger aerosols (radius > 1μm). It is also reflected by the spectral shape of the eigenvector. The differences can be related to the type of aerosols present at both locations, and the amplitude function can be associated to meteorological conditions. The amplitude function also indicates the episodes with the maximum/minimum continental influence. The results of this analysis will be used in upgrades of the ANAM model.

  7. Ecological impacts of ocean acidification in coastal marine environments (Invited)

    NASA Astrophysics Data System (ADS)

    Harley, C.; Crim, R.; Gooding, R.; Nienhuis, S.; Tang, E.

    2010-12-01

    Rising atmospheric carbon dioxide concentrations are driving rapid and potentially unprecedented reductions in pH and carbonate ion availability in coastal marine environments. This process, known as ocean acidification (OA), has far-reaching implications for the performance and survival of marine organisms, particularly those with calcified shells and skeletons. Here, we highlight the ways in which OA impacts plants and animals in a coastal benthic food web, with an emphasis on what we know and what we don’t know about the ways in which the responses of individual organisms will scale up to long-term changes in community structure. Our system of interest is the rocky shore benthic community that is broadly represented from Alaska through California. Ecologically important species include producers (micro- and macro-algae), grazers (urchins and gastropods), filter feeders (mussels), and predators (sea stars). Although the direct effects of OA on coastal phytoplankton and kelps remain poorly understood, it appears as though elevated CO2 will increase the doubling rate of benthic diatoms. Small changes in food supply, however, may pale in comparison to the direct effects of OA on heavily calcified grazers and filter feeders. Sea urchin and mussel growth are both reduced by increased CO2 in the lab, and decadal-scale reductions in pH are associated with reduced turban snail growth in the field. Although adult abalone growth appears to be unaffected by CO2, larval development is impaired and larval survival is significantly reduced in acidified conditions. In contrast to the negative effects of OA on heavily calcified herbivores and filter feeders, lightly calcified sea stars actually grow faster when CO2 is experimentally increased. The acidification-induced changes described here are likely to result in substantial shifts in the benthic ecosystem. Increasing predation pressure may further reduce the abundance of grazers and filter feeders that are already suffering

  8. Task performance under water. An evaluation of manual dexterity efficiency in the open ocean underwater environment.

    PubMed

    Hancock, P A; Miller, E K

    1986-06-01

    The present review examines studies which have reported on the performance of submerged operators on manual dexterity tasks in the practical arena of the open ocean underwater environment. The previous emphasis on the primacy of the factor situational anxiety, in degrading efficiency, is questioned. The case for environmentally-based factors and performer skill level as potent influences on performance is advanced. In postulating a potential linear relationship between depth of operation and performance decrement for air-breathing divers, the review seeks to stimulate further experimental examination of this important applied issue. PMID:15676579

  9. TARA OCEANS: A Global Analysis of Oceanic Plankton Ecosystems (2013 DOE JGI Genomics of Energy and Environment 8th Annual User Meeting)

    SciTech Connect

    Karsenti, Eric

    2013-03-01

    Eric Karsenti of EMBL delivers the closing keynote on "TARA OCEANS: A Global Analysis of Oceanic Plankton Ecosystems" at the 8th Annual Genomics of Energy & Environment Meeting on March 28, 2013 in Walnut Creek, Calif.

  10. Coastal Ocean Observing Network - Open Source Architecture for Data Management and Web-Based Data Services

    NASA Astrophysics Data System (ADS)

    Pattabhi Rama Rao, E.; Venkat Shesu, R.; Udaya Bhaskar, T. V. S.

    2012-07-01

    The observations from the oceans are the backbone for any kind of operational services, viz. potential fishing zone advisory services, ocean state forecast, storm surges, cyclones, monsoon variability, tsunami, etc. Though it is important to monitor open Ocean, it is equally important to acquire sufficient data in the coastal ocean through coastal ocean observing systems for re-analysis, analysis and forecast of coastal ocean by assimilating different ocean variables, especially sub-surface information; validation of remote sensing data, ocean and atmosphere model/analysis and to understand the processes related to air-sea interaction and ocean physics. Accurate information and forecast of the state of the coastal ocean at different time scales is vital for the wellbeing of the coastal population as well as for the socio-economic development of the country through shipping, offshore oil and energy etc. Considering the importance of ocean observations in terms of understanding our ocean environment and utilize them for operational oceanography, a large number of platforms were deployed in the Indian Ocean including coastal observatories, to acquire data on ocean variables in and around Indian Seas. The coastal observation network includes HF Radars, wave rider buoys, sea level gauges, etc. The surface meteorological and oceanographic data generated by these observing networks are being translated into ocean information services through analysis and modelling. Centralized data management system is a critical component in providing timely delivery of Ocean information and advisory services. In this paper, we describe about the development of open-source architecture for real-time data reception from the coastal observation network, processing, quality control, database generation and web-based data services that includes on-line data visualization and data downloads by various means.

  11. Real-time generation of infrared ocean scene based on GPU

    NASA Astrophysics Data System (ADS)

    Jiang, Zhaoyi; Wang, Xun; Lin, Yun; Jin, Jianqiu

    2007-12-01

    Infrared (IR) image synthesis for ocean scene has become more and more important nowadays, especially for remote sensing and military application. Although a number of works present ready-to-use simulations, those techniques cover only a few possible ways of water interacting with the environment. And the detail calculation of ocean temperature is rarely considered by previous investigators. With the advance of programmable features of graphic card, many algorithms previously limited to offline processing have become feasible for real-time usage. In this paper, we propose an efficient algorithm for real-time rendering of infrared ocean scene using the newest features of programmable graphics processors (GPU). It differs from previous works in three aspects: adaptive GPU-based ocean surface tessellation, sophisticated balance equation of thermal balance for ocean surface, and GPU-based rendering for infrared ocean scene. Finally some results of infrared image are shown, which are in good accordance with real images.

  12. Oceanic minerals: their origin, nature of their environment, and significance.

    PubMed

    Kastner, M

    1999-03-30

    The chemical and isotopic compositions of oceanic biogenic and authigenic minerals contain invaluable information on the evolution of seawater, hence on the history of interaction between tectonics, climate, ocean circulation, and the evolution of life. Important advances and greater understanding of (a) key minor and trace element cycles with various residence times, (b) isotopic sources and sinks and fractionation behaviors, and (c) potential diagenetic problems, as well as developments in high-precision instrumentation, recently have been achieved. These advances provided new compelling evidence that neither gradualism nor uniformitarianism can explain many of the new important discoveries obtained from the chemistry and isotopic compositions of oceanic minerals. Presently, the best-developed geochemical proxies in biogenic carbonates are 18O/16O and Sr/Ca ratios (possibly Mg/Ca) for temperature; 87Sr/86Sr for input sources, Cd/Ca and Ba/Ca ratios for phosphate and alkalinity concentrations, respectively, thus also for ocean circulation; 13C/12C for ocean productivity; B isotopes for seawater pH;, U, Th isotopes, and 14C for dating; and Sr and Mn concentrations for diagenesis. The oceanic authigenic minerals most widely used for chemical paleoceanography are barite, evaporite sulfates, and hydrogenous ferromanganese nodules. Marine barite is an effective alternative monitor of seawater 87Sr/86Sr, especially where carbonates are diagenetically altered or absent. It also provides a high-resolution record of seawater sulfate S isotopes, (evaporite sulfates only carry an episodic record), with new insights on factors affecting the S and C cycles and atmospheric oxygen. High-resolution studies of Sr, Nd, and Pb isotopes of well-dated ferromanganese nodules contain invaluable records on climate driven changes in oceanic circulation. PMID:10097047

  13. Oceanic minerals: Their origin, nature of their environment, and significance

    PubMed Central

    Kastner, Miriam

    1999-01-01

    The chemical and isotopic compositions of oceanic biogenic and authigenic minerals contain invaluable information on the evolution of seawater, hence on the history of interaction between tectonics, climate, ocean circulation, and the evolution of life. Important advances and greater understanding of (a) key minor and trace element cycles with various residence times, (b) isotopic sources and sinks and fractionation behaviors, and (c) potential diagenetic problems, as well as developments in high-precision instrumentation, recently have been achieved. These advances provided new compelling evidence that neither gradualism nor uniformitarianism can explain many of the new important discoveries obtained from the chemistry and isotopic compositions of oceanic minerals. Presently, the best-developed geochemical proxies in biogenic carbonates are 18O/16O and Sr/Ca ratios (possibly Mg/Ca) for temperature; 87Sr/86Sr for input sources, Cd/Ca and Ba/Ca ratios for phosphate and alkalinity concentrations, respectively, thus also for ocean circulation; 13C/12C for ocean productivity; B isotopes for seawater pH;, U, Th isotopes, and 14C for dating; and Sr and Mn concentrations for diagenesis. The oceanic authigenic minerals most widely used for chemical paleoceanography are barite, evaporite sulfates, and hydrogenous ferromanganese nodules. Marine barite is an effective alternative monitor of seawater 87Sr/86Sr, especially where carbonates are diagenetically altered or absent. It also provides a high-resolution record of seawater sulfate S isotopes, (evaporite sulfates only carry an episodic record), with new insights on factors affecting the S and C cycles and atmospheric oxygen. High-resolution studies of Sr, Nd, and Pb isotopes of well-dated ferromanganese nodules contain invaluable records on climate driven changes in oceanic circulation. PMID:10097047

  14. Ocean Wave Simulation Based on Wind Field.

    PubMed

    Li, Zhongyi; Wang, Hao

    2016-01-01

    Ocean wave simulation has a wide range of applications in movies, video games and training systems. Wind force is the main energy resource for generating ocean waves, which are the result of the interaction between wind and the ocean surface. While numerous methods to handle simulating oceans and other fluid phenomena have undergone rapid development during the past years in the field of computer graphic, few of them consider to construct ocean surface height field from the perspective of wind force driving ocean waves. We introduce wind force to the construction of the ocean surface height field through applying wind field data and wind-driven wave particles. Continual and realistic ocean waves result from the overlap of wind-driven wave particles, and a strategy was proposed to control these discrete wave particles and simulate an endless ocean surface. The results showed that the new method is capable of obtaining a realistic ocean scene under the influence of wind fields at real time rates. PMID:26808718

  15. Ocean Wave Simulation Based on Wind Field

    PubMed Central

    2016-01-01

    Ocean wave simulation has a wide range of applications in movies, video games and training systems. Wind force is the main energy resource for generating ocean waves, which are the result of the interaction between wind and the ocean surface. While numerous methods to handle simulating oceans and other fluid phenomena have undergone rapid development during the past years in the field of computer graphic, few of them consider to construct ocean surface height field from the perspective of wind force driving ocean waves. We introduce wind force to the construction of the ocean surface height field through applying wind field data and wind-driven wave particles. Continual and realistic ocean waves result from the overlap of wind-driven wave particles, and a strategy was proposed to control these discrete wave particles and simulate an endless ocean surface. The results showed that the new method is capable of obtaining a realistic ocean scene under the influence of wind fields at real time rates. PMID:26808718

  16. Forecasting the ocean optical environment in support of Navy mine warfare operations

    NASA Astrophysics Data System (ADS)

    Ladner, S. D.; Arnone, R.; Jolliff, J.; Casey, B.; Matulewski, K.

    2012-06-01

    A 3D ocean optical forecast system called TODS (Tactical Ocean Data System) has been developed to determine the performance of underwater LIDAR detection/identification systems. TODS fuses optical measurements from gliders, surface satellite optical properties, and 3D ocean forecast circulation models to extend the 2-dimensional surface satellite optics into a 3-dimensional optical volume including subsurface optical layers of beam attenuation coefficient (c) and diver visibility. Optical 3D nowcast and forecasts are combined with electro-optical identification (EOID) models to determine the underwater LIDAR imaging performance field used to identify subsurface mine threats in rapidly changing coastal regions. TODS was validated during a recent mine warfare exercise with Helicopter Mine Countermeasures Squadron (HM-14). Results include the uncertainties in the optical forecast and lidar performance and sensor tow height predictions that are based on visual detection and identification metrics using actual mine target images from the EOID system. TODS is a new capability of coupling the 3D optical environment and EOID system performance and is proving important for the MIW community as both a tactical decision aid and for use in operational planning, improving timeliness and efficiency in clearance operations.

  17. The Chinese FY-1 Meteorological Satellite Application in Observation on Oceanic Environment

    NASA Astrophysics Data System (ADS)

    Weimin, S.

    meteorological satellite is stated in this paper. exploration of the ocean resources has been a very important question of global strategy in the world. The exploration of the ocean resources includes following items: Making full use of oceanic resources and space, protecting oceanic environment. to observe the ocean is by using of satellite. In 1978, US successfully launched the first ocean observation satellite in the world --- Sea Satellite. It develops ancient oceanography in to advanced space-oceanography. FY-1 B and FY- IC respectively. High quality data were acquired at home and abroad. FY-1 is Chinese meteorological satellite, but with 0.43 ~ 0.48 μm ,0.48 ~ 0.53 μm and 0.53 ~ 0.58 μm three ocean color channels, actually it is a multipurpose remote sensing satellite of meteorology and oceanography. FY-1 satellite's capability of observation on ocean partly, thus the application field is expanded and the value is increased. With the addition of oceanic channels on FY-1, the design of the satellite is changed from the original with meteorological observation as its main purpose into remote sensing satellite possessing capability of observing meteorology and ocean as well. Thus, the social and economic benefit of FY-1 is increased. the social and economic benefit of the development of the satellite is the key technique in the system design of the satellite. technically feasible but also save the funds in researching and manufacturing of the satellite, quicken the tempo of researching and manufacturing satellite. the scanning radiometer for FY-1 is conducted an aviation experiment over Chinese ocean. This experiment was of vital importance to the addition of oceanic observation channel on FY-1. FY-1 oceanic channels design to be correct. detecting ocean color. This is the unique character of Chinese FY-1 meteorological satellite. meteorological remote sensing channel on FY-1 to form detecting capability of three visible channels: red, yellow and blue

  18. Response to Comment on "Open-ocean fish reveal an omnidirectional solution to camouflage in polarized environments".

    PubMed

    Brady, Parrish; Gilerson, Alex; Kattawar, George; Sullivan, Jim; Twardowski, Mike; Dierssen, Heidi; Cummings, Molly

    2016-08-01

    Cronin et al take issue with our evidence for polarocryptic carangid fish based on concerns of pseudoreplication, our contrast metric, and habitat. We clarify (i) the importance of camouflage in near-surface open ocean environments and (ii) the use of a Stokes contrast metric and further (iii) conduct individual-based statistics on our data set to confirm the reported polarocrypsis patterns. PMID:27493177

  19. Ocean predictability studies in a parallel computing environment. Final report

    SciTech Connect

    Leary, R.H.

    1992-11-01

    The goal of the SDSC effort described here is to evaluate the performance potential of the Oberhuber isopycnal (OPYC) ocean global circulation model on the 64-node iPSC/860 parallel computer at SDSC and its near term successor, the Intel Paragon, relative to that of a single vector processor of a CRAY Y-MP and its near term successor, the CRAY C90. This effort is in support of a larger joint project with researchers at Scripps Institution of Oceanography to study the properties of long (10 to 100-year scale), computationally intensive integrations of ocean global circulation models. Generally, performance of the OPYC model on the iPSC/860 has proved quite disappointing, with a simplified version of the entire model running at approximately 1.4 Mflops on a single i860 node in its original form and after extensive optimization, including coding in assembler, at 3.2 Mflops. The author estimates overall performance to be limited to 75 Mflops or less on the 64-node machine, as compared to 180 Mflops for a single CRAY Y-MP processor and 500 Mflops for a single CRAY C90 processor. Similarly, he believes an implementation on an Intel Paragon, even with several hundred nodes, will not be competitive with a single processor C90 implementation. Additionally, the Hamburg Large Scale Geostrophic (LSG) model has been implemented on high-performance workstations and evaluated for its computational potential as an alternative to OPYC for the long term integrations.

  20. Iron Resources and Oceanic Nutrients: Advancement of Global Environment Simulations

    NASA Astrophysics Data System (ADS)

    Debaar, H. J.

    2002-12-01

    The concept of a single factor limiting plankton blooms, is presently giving way to co-limitation by light, and the nutrients N, P, Si and Fe. Primary production, export into the deep sea, and CO2 uptake from the atmosphere together form the 'biological pump' in Ocean Biogeochemical Climate Models (OBCM's). Thus far OBCM's assume just one limiting nutrient (P) and one universal phytoplankton species, for C budgets and CO2 exchange. New realistic OBCM's are being developed for budgeting and exchanges of both CO2 and DMS, implementing (i) co-limitation by 4 nutrients of 5 major taxonomic classes of phytoplankton, (ii) DMS(P) pathways, (iii) global iron cycling, (iv) chemical forms of iron and (v) iron supply into surface waters. The new OBCM's will predict realistic climate scenario's, notably climatic feedbacks on oceanic biogeochemistry. IRONAGES is a European consortium of twelve institutes and is coordinated by Royal NIOZ. Input from below of iron from anoxic sediments of coastal margins has been assessed (March 2002) along a 2-D vertical section from Europe into the centre of the north Atlantic. Input from above of Fe(II) dissolved in rainwater from Sahara dust blown over the central Atlantic will be quantified at sea (October 2002), and related to observed plankton production. Different chemical forms of iron are being assessed and a certification excercise for Fe in seawater also under aegis of SCOR Working Group 109 is being completed (December 2002). For two major DMS-producing algal groups Phaeocystis sp. and Emiliania huxleyi the life cycle, Fe limitation, export production, CO2 uptake and DMS emissions have been synthesized from existing literature and laboratory experiments. This is being fed into ecosystem modeling, as well as into DMS(P) pathway modeling. Also know-how has been synthesized for three other major classes (diatoms, N2-fixing Trichodesmium and nano-pico-plankton) and fed into the ecosystem modeling. Pathways of DMS(P) in blooms are being

  1. Parallel Implementation of the Unified Curvilinear Ocean and Atmospheric (UCOAM) Model and Supporting Computational Environment

    NASA Astrophysics Data System (ADS)

    Thomas, Mary Prouty

    A new parallel framework and associated cyberinfrastructure has been verified to efficiently and accurately run Unified Curvilinear Ocean and Atmospheric Model (UCOAM) simulations. UCOAM is a high-resolution (sub-km), non-hydrostatic, large eddie simulation (LES) computational fluid dynamics model that is capable of running ocean and atmospheric simulations. UCOAM is the only environmental model in existence today that uses a full 3D curvilinear coordinate system, which results in increased accuracy, resolution, and reduced times to solution. UCOAM is a petascale model: for 10 meter resolutions, array sizes will scale as theta(1012) bytes, resulting in a large on node memory footprint; meaningful model simulations will generate terabytes of data and run for long periods of time; the non-hydrostatic model will require 3D communications. A parallel framework (PFW) has been developed that is capable of distributing data and computations across arbitrary 3D processor arrangements, of managing the Arikawa-C staggered grid variables and several finite difference stencils. The framework is written in Fortran 95, is component based and modular, and is completely decoupled from the application. The PFW communication model is based on the Message Passing Interface (MPI), but can be extended to include other parallel approaches. The framework uses a simple block-block data distribution scheme and can handle arbitrary processor arrangements. The framework manages and tracks communications between arbitrary groups of processors in 1, 2, and 3 dimensions, and is aware of the locations of axial, diagonal and tri-diagonal neighbors. The application framework is based on the PFW and can support any UCOAM based application. To facilitate simulations, a computational environment (CE) based on the Cyberinfrastructure Web Application Framework (CyberWeb) has been developed to support access to and development of web services, portals, and cyberinfrastructure. The parallel framework has

  2. 11th National Conference on Science, Policy, and the Environment: Our Changing Oceans

    SciTech Connect

    Peter Saundry

    2012-04-17

    On January 19-21, 2011, The National Council for Science and the Environment (NCSE) successfully convened its 11th National Conference on Science, Policy and the Environment: Our Changing Oceans in Washington, DC at the Ronald Reagan Building and International Trade Center. Over 1,247 participants attended the conference, representing federal, state and local governments, university and colleges across the US, civil society organizations, the business community, and international entities. In addition, the conference was webcast to an audience across several states. The conference provided a forum to examine the profound changes our ocean will undergo over the next 25-50 years and share various perspectives on the new research, tools, and policy initiatives to protect and sustain our ocean. Conference highlights and recommendations are available to the public on NCSE's conference website, www.OurChangingOceans.org.

  3. Plastic pollution in the marine environment. (Latest citations from Oceanic Abstracts). Published Search

    SciTech Connect

    Not Available

    1993-02-01

    The bibliography contains citations concerning the adverse effects of synthetic polymers on oceans and beaches. The citations examine the impact of discarded plastics upon fish, seabirds, and other aquatic animals. The sources of plastic litter and the efforts of coastal communities to manage plastics pollution are referenced. International agreements designed to protect the marine environment by banning ocean dumping of plastics are discussed. (Contains a minimum of 145 citations and includes a subject term index and title list.)

  4. Compared chemistry of natural gas hydrates from different oceanic environments

    NASA Astrophysics Data System (ADS)

    Charlou, J.; Donval, J.; Ondreas, H.; Foucher, J.; Voisset, M.; Chazallon, B.; Jean-Baptiste, P.; Sauter, E.; Levache, D.

    2004-12-01

    Natural gas hydrates are generally associated with pockmarks or mud volcanoes on margins. They occurred both in deep sedimentary structures, and sometimes as outcrops on the seafloor. The gas hydrates studied here were collected from gravity sediment cores and occur as small fragments and massive crystal aggregates, mostly disseminated irregularly in the sediment. In most cases, they escape in the overlying deep seawater creating CH4-rich plumes which extend 100-150 m above the seafloor. These plumes are also enriched in particles, manganese, iron related to discharges of high turbid fluids issued from sediments and in all cases methane is rejected from sediment as free gas or as a consequence of the decomposition of gas hydrates. Specific equipments are necessary for collecting, and storing these gas hydrates in good conditions to avoid decomposition. The crystalline structure of solid gas hydrates is studied by Raman Spectrometry and Synchrotron techniques and show mainly methane gas hydrate of cubic Structure I. Analyses of hydrate water show variations (depletions or enrichments) of mineral elements compared to ambient deep seawater. Gas analysis shows that CH4 is the major component but CO2 and heavier gases (C2H4, C2H6, H2S) are also present as traces. In addition, many families of organic compounds detected by chromatography-mass spectrometry are present as traces. In most cases, the carbon and hydrogen isotopic data indicate a primarily microbial origin for the CH4 which is generated through bacterial CO2 reduction. All these chemical data contribute to understand the origin, formation and stability of gas hydrates trapped in sediments on oceanic margins. Specimens of natural gas hydrates recently collected on the African and Norvegian margins will be discussed.

  5. The upper ocean environment responses to typhoon Prapiroon (2012)

    NASA Astrophysics Data System (ADS)

    Li, Ying X.; Yang, Yuan J.; Sun, Liang; Fu, Yun F.

    2014-11-01

    Satellite-observed daily sea level anomaly (SLA), sea surface temperature (SST) and sea surface salinity (SSS) are used to determine the impact of the typhoon Prapiroon (2012) on the sea surface. The typhoon, Prapiroon, has a unique track when it went through the area (126°E-133°E, 17°N-25.5°N), where it influenced the sea greatly. For example, the lowest SST in this area was 25.2°C on October 8 before it entered, while the SST dropped to 20.7 °C on October 15. On the other hand, the lowest SLA dropped from -20 cm (on October 8) to -53 cm (on October 29). Accompanied with this, the SSS increased about 0.8-0.9 psu in some region. This is qualitative but quantitative agree with the Argo data of 0.2 psu SSS increase. One possible reason is the precipitation of typhoon, as the SSS data by Aquarius are easily affected by precipitation. And such significant SST cooling and SSS increasing were mainly due to vertical mixing, caused by longterm strong wind stirring brought by Parpiroon. We find that both the cold patch and eddies were transported westward. The horizontal advection took the cold water to 100 km away, this non-local effect could have notable impact on ocean dynamics and bio-physical processes. In addition we analyzed the possible factors of the temperature and salinity decreasing below the thermocline by calculating the Ekman pumping velocity due to the typhoon. It reveals that this is caused by Ekman pumping and upwelling in the cyclonic eddy, and Ekman pumping is the main factor.

  6. Radioactive pollution: ocean environments. January 1974-May 1989 (Citations from Oceanic Abstracts). Report for January 1974-May 1989

    SciTech Connect

    Not Available

    1989-06-01

    This bibliography contains citations concerning radioactive pollution of the marine environment. Distributions of radionuclides indicative of artificial radioactive contamination are discussed including iodine-131, various uranium isotopes, cesium-137, cobalt-60, strontium-90, ruthenium-160, and plutonium isotopes. Ecosystems considered include coral reefs and atolls, planktonic zones in the open ocean, salt marshes, estuaries, coastal waters, and the Mediterranean Sea. Sources of radioactive contamination examined include atomic bomb blasts, fossil-fuel combustion, radioactive waste disposal, and nuclear accidents. Experimental simulation of radionuclide transport in marine biota is included. (Contains 108 citations fully indexed and including a title list.)

  7. Core microbial functional activities in ocean environments revealed by global metagenomic profiling analyses.

    PubMed

    Ferreira, Ari J S; Siam, Rania; Setubal, João C; Moustafa, Ahmed; Sayed, Ahmed; Chambergo, Felipe S; Dawe, Adam S; Ghazy, Mohamed A; Sharaf, Hazem; Ouf, Amged; Alam, Intikhab; Abdel-Haleem, Alyaa M; Lehvaslaiho, Heikki; Ramadan, Eman; Antunes, André; Stingl, Ulrich; Archer, John A C; Jankovic, Boris R; Sogin, Mitchell; Bajic, Vladimir B; El-Dorry, Hamza

    2014-01-01

    Metagenomics-based functional profiling analysis is an effective means of gaining deeper insight into the composition of marine microbial populations and developing a better understanding of the interplay between the functional genome content of microbial communities and abiotic factors. Here we present a comprehensive analysis of 24 datasets covering surface and depth-related environments at 11 sites around the world's oceans. The complete datasets comprises approximately 12 million sequences, totaling 5,358 Mb. Based on profiling patterns of Clusters of Orthologous Groups (COGs) of proteins, a core set of reference photic and aphotic depth-related COGs, and a collection of COGs that are associated with extreme oxygen limitation were defined. Their inferred functions were utilized as indicators to characterize the distribution of light- and oxygen-related biological activities in marine environments. The results reveal that, while light level in the water column is a major determinant of phenotypic adaptation in marine microorganisms, oxygen concentration in the aphotic zone has a significant impact only in extremely hypoxic waters. Phylogenetic profiling of the reference photic/aphotic gene sets revealed a greater variety of source organisms in the aphotic zone, although the majority of individual photic and aphotic depth-related COGs are assigned to the same taxa across the different sites. This increase in phylogenetic and functional diversity of the core aphotic related COGs most probably reflects selection for the utilization of a broad range of alternate energy sources in the absence of light. PMID:24921648

  8. Core Microbial Functional Activities in Ocean Environments Revealed by Global Metagenomic Profiling Analyses

    PubMed Central

    Ferreira, Ari J. S.; Siam, Rania; Setubal, João C.; Moustafa, Ahmed; Sayed, Ahmed; Chambergo, Felipe S.; Dawe, Adam S.; Ghazy, Mohamed A.; Sharaf, Hazem; Ouf, Amged; Alam, Intikhab; Abdel-Haleem, Alyaa M.; Lehvaslaiho, Heikki; Ramadan, Eman; Antunes, André; Stingl, Ulrich; Archer, John A. C.; Jankovic, Boris R.; Sogin, Mitchell; Bajic, Vladimir B.; El-Dorry, Hamza

    2014-01-01

    Metagenomics-based functional profiling analysis is an effective means of gaining deeper insight into the composition of marine microbial populations and developing a better understanding of the interplay between the functional genome content of microbial communities and abiotic factors. Here we present a comprehensive analysis of 24 datasets covering surface and depth-related environments at 11 sites around the world's oceans. The complete datasets comprises approximately 12 million sequences, totaling 5,358 Mb. Based on profiling patterns of Clusters of Orthologous Groups (COGs) of proteins, a core set of reference photic and aphotic depth-related COGs, and a collection of COGs that are associated with extreme oxygen limitation were defined. Their inferred functions were utilized as indicators to characterize the distribution of light- and oxygen-related biological activities in marine environments. The results reveal that, while light level in the water column is a major determinant of phenotypic adaptation in marine microorganisms, oxygen concentration in the aphotic zone has a significant impact only in extremely hypoxic waters. Phylogenetic profiling of the reference photic/aphotic gene sets revealed a greater variety of source organisms in the aphotic zone, although the majority of individual photic and aphotic depth-related COGs are assigned to the same taxa across the different sites. This increase in phylogenetic and functional diversity of the core aphotic related COGs most probably reflects selection for the utilization of a broad range of alternate energy sources in the absence of light. PMID:24921648

  9. Development of a computational environment for the General Curvilinear Ocean Model

    NASA Astrophysics Data System (ADS)

    Thomas, Mary P.; Castillo, Jose E.

    2009-07-01

    The General Curvilinear Ocean Model (GCOM) differs significantly from the traditional approach, where the use of Cartesian coordinates forces the model to simulate terrain as a series of steps. GCOM utilizes a full three-dimensional curvilinear transformation, which has been shown to have greater accuracy than similar models and to achieve results more efficiently. The GCOM model has been validated for several types of water bodies, different coastlines and bottom shapes, including the Alarcon Seamount, Southern California Coastal Region, the Valencia Lake in Venezuela, and more recently the Monterey Bay. In this paper, enhancements to the GCOM model and an overview of the computational environment (GCOM-CE) are presented. Model improvements include migration from F77 to F90; approach to a component design; and initial steps towards parallelization of the model. Through the use of the component design, new models are being incorporated including biogeochemical, pollution, and sediment transport. The computational environment is designed to allow various client interactions via secure Web applications (portal, Web services, and Web 2.0 gadgets). Features include building jobs, managing and interacting with long running jobs; managing input and output files; quick visualization of results; publishing of Web services to be used by other systems such as larger climate models. The CE is based mainly on Python tools including a grid-enabled Pylons Web application Framework for Web services, pyWSRF (python-Web Services-Resource Framework), pyGlobus based web services, SciPy, and Google code tools.

  10. Cycling of DDT in the global environment 1950-2002: World ocean returns the pollutant

    NASA Astrophysics Data System (ADS)

    Stemmler, Irene; Lammel, Gerhard

    2009-12-01

    The global distribution and fate of the insecticide DDT was modeled for the first time using a spatially resolved global multicompartment chemistry-transport model comprising a 3D coupled atmosphere and ocean GCM, coupled to 2D vegetation surfaces and top soils. DDT enters the model environment as a pesticide in agriculture only. Final sinks of DDT in the total environment are degradation in air (hydroxyl radical reaction), on vegetation surfaces, in ocean sediments and soils. The process resolution of the ocean compartment, i.e., either a fixed or variable size and sinking velocity of suspended particles, has almost no effect on the large-scale cycling and fate of DDT. The residence times in various ocean basins were declining but varied regionally. The global ocean absorbed until 1977 and since then has been losing DDT, while large sea areas are still accumulating the pollutant. The main sink is volatilization to the atmosphere. In 1990, the year when emissions ceased, 292 kt of DDT were deposited to the global ocean, 301 kt were volatilized, and 41 kt were exported from the surface layer to the deeper levels. The sea region that has been representing the most significant (secondary) DDT source is the western N Atlantic (Gulf stream and N Atlantic Drift regions). It has been a source since approximately 1970. Also large parts of the tropical ocean and the southern mid-latitude ocean have turned net volatilizational (i.e., volatilization flux > deposition flux) during the 1980s. Despite the emissions migrating southward as a consequence of substance ban in mid latitudes, the geographic distribution of the contaminant (and, hence, environmental exposure) has been migrating steadily northward since the 1960s.

  11. Ocean Model Analysis and Prediction System (Ocean Maps): Operational Ocean Forecasting Base on Near Real-Time Satellite Altimetry

    NASA Astrophysics Data System (ADS)

    Brassington, G. B.

    2006-07-01

    BLU Elink> is a join t Australian governmen t initiative to develop Austr alia's f irst operational ocean forecasting system called O cean MAPS. The project has transitioned to th e implemen tation and trial phase using the infrastructure of the Bureau of Meteorology. OceanMAPS has a g lobal grid with 1/10° by 1/10° resolution in the Australian region (90E-180E, 70S- 16N) and uses the Modular Ocean Model version 4 optimised for the NEC SX6. The analysis uses an ensemb le based multi-variate optimal interpolation scheme wh ere model error cov ariances ar e der ived from a 72-member ensemble of in tra-seasonal anomalies based on a 12-year ocean only model integration. The scheme has been formulated to assimilate near real- time sea level heigh t anomalies processed from Jason-1, ENVISAT and Geosat Follow-On and profile observations including Argo, X BT and the TAO array. The operation al configuration including the data manag emen t of the near real- time observ ations is review ed.

  12. Studies of oceanic tectonics based on GEOS-3 satellite altimetry

    NASA Technical Reports Server (NTRS)

    Poehls, K. A.; Kaula, W. M.; Schubert, G.; Sandwell, D.

    1979-01-01

    Using statistical analysis, geoidal admittance (the relationship between the ocean geoid and seafloor topography) obtained from GEOS-3 altimetry was compared to various model admittances. Analysis of several altimetry tracks in the Pacific Ocean demonstrated a low coherence between altimetry and seafloor topography except where the track crosses active or recent tectonic features. However, global statistical studies using the much larger data base of all available gravimetry showed a positive correlation of oceanic gravity with topography. The oceanic lithosphere was modeled by simultaneously inverting surface wave dispersion, topography, and gravity data. Efforts to incorporate geoid data into the inversion showed that the base of the subchannel can be better resolved with geoid rather than gravity data. Thermomechanical models of seafloor spreading taking into account differing plate velocities, heat source distributions, and rock rheologies were discussed.

  13. Ontology-Based Modelling of Ocean Satellite Images

    NASA Astrophysics Data System (ADS)

    Almendros-Jiménez, Jesús M.; Piedra, José A.; Cantón, Manuel

    In this paper we will define an ontology about the semantic content of ocean satellite images in which we are able to represent types of ocean structures, spatial and morphological concepts, and knowledge about measures of temperature, chrolophyll concentration, among others. Such ontology will provide the basis of a classification system based on the low-level features of images. We have tested our approach using the Protegé semantic web tool.

  14. Self-Organizing Maps-based ocean currents forecasting system.

    PubMed

    Vilibić, Ivica; Šepić, Jadranka; Mihanović, Hrvoje; Kalinić, Hrvoje; Cosoli, Simone; Janeković, Ivica; Žagar, Nedjeljka; Jesenko, Blaž; Tudor, Martina; Dadić, Vlado; Ivanković, Damir

    2016-01-01

    An ocean surface currents forecasting system, based on a Self-Organizing Maps (SOM) neural network algorithm, high-frequency (HF) ocean radar measurements and numerical weather prediction (NWP) products, has been developed for a coastal area of the northern Adriatic and compared with operational ROMS-derived surface currents. The two systems differ significantly in architecture and algorithms, being based on either unsupervised learning techniques or ocean physics. To compare performance of the two methods, their forecasting skills were tested on independent datasets. The SOM-based forecasting system has a slightly better forecasting skill, especially during strong wind conditions, with potential for further improvement when data sets of higher quality and longer duration are used for training. PMID:26979129

  15. Self-Organizing Maps-based ocean currents forecasting system

    PubMed Central

    Vilibić, Ivica; Šepić, Jadranka; Mihanović, Hrvoje; Kalinić, Hrvoje; Cosoli, Simone; Janeković, Ivica; Žagar, Nedjeljka; Jesenko, Blaž; Tudor, Martina; Dadić, Vlado; Ivanković, Damir

    2016-01-01

    An ocean surface currents forecasting system, based on a Self-Organizing Maps (SOM) neural network algorithm, high-frequency (HF) ocean radar measurements and numerical weather prediction (NWP) products, has been developed for a coastal area of the northern Adriatic and compared with operational ROMS-derived surface currents. The two systems differ significantly in architecture and algorithms, being based on either unsupervised learning techniques or ocean physics. To compare performance of the two methods, their forecasting skills were tested on independent datasets. The SOM-based forecasting system has a slightly better forecasting skill, especially during strong wind conditions, with potential for further improvement when data sets of higher quality and longer duration are used for training. PMID:26979129

  16. Self-Organizing Maps-based ocean currents forecasting system

    NASA Astrophysics Data System (ADS)

    Vilibić, Ivica; Šepić, Jadranka; Mihanović, Hrvoje; Kalinić, Hrvoje; Cosoli, Simone; Janeković, Ivica; Žagar, Nedjeljka; Jesenko, Blaž; Tudor, Martina; Dadić, Vlado; Ivanković, Damir

    2016-03-01

    An ocean surface currents forecasting system, based on a Self-Organizing Maps (SOM) neural network algorithm, high-frequency (HF) ocean radar measurements and numerical weather prediction (NWP) products, has been developed for a coastal area of the northern Adriatic and compared with operational ROMS-derived surface currents. The two systems differ significantly in architecture and algorithms, being based on either unsupervised learning techniques or ocean physics. To compare performance of the two methods, their forecasting skills were tested on independent datasets. The SOM-based forecasting system has a slightly better forecasting skill, especially during strong wind conditions, with potential for further improvement when data sets of higher quality and longer duration are used for training.

  17. Brachiopod taxa and shell portions reliably recording past ocean environments: Toward establishing a robust paleoceanographic proxy

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kazuyuki; Asami, Ryuji; Iryu, Yasufumi

    2011-07-01

    Fossils of rhynchonelliform brachiopods (marine invertebrates) constitute ˜70% of the samples used for delineating a well-known Phanerozoic trend in oxygen isotope composition (δ18O) of low-Mg calcite shells. The trend represents secular variations in temperature and/or δ18O of ancient seawater. However, the use of brachiopods as a paleoceanographic proxy is based on the presupposition that the shell calcite is precipitated in isotopic equilibrium with ambient seawater. Here, we show that high-resolution time series of the shell δ18O values along the maximum growth axes of two long-lived cool-water brachiopods are identical to, greater than, or less than those of calcite precipitated in isotopic equilibrium with ambient seawater, depending on the difference in shell growth rates. Coupled with δ18O data from subtropical and warm-temperate brachiopod species examined in our previous studies, we provide a sound framework illustrating which taxa and shell portions reliably recorded past ocean environments.

  18. Carbon-based ocean productivity and phytoplankton physiology from space

    NASA Astrophysics Data System (ADS)

    Behrenfeld, Michael J.; Boss, Emmanuel; Siegel, David A.; Shea, Donald M.

    2005-03-01

    Ocean biogeochemical and ecosystem processes are linked by net primary production (NPP) in the ocean's surface layer, where inorganic carbon is fixed by photosynthetic processes. Determinations of NPP are necessarily a function of phytoplankton biomass and its physiological status, but the estimation of these two terms from space has remained an elusive target. Here we present new satellite ocean color observations of phytoplankton carbon (C) and chlorophyll (Chl) biomass and show that derived Chl:C ratios closely follow anticipated physiological dependencies on light, nutrients, and temperature. With this new information, global estimates of phytoplankton growth rates (μ) and carbon-based NPP are made for the first time. Compared to an earlier chlorophyll-based approach, our carbon-based values are considerably higher in tropical oceans, show greater seasonality at middle and high latitudes, and illustrate important differences in the formation and demise of regional algal blooms. This fusion of emerging concepts from the phycological and remote sensing disciplines has the potential to fundamentally change how we model and observe carbon cycling in the global oceans.

  19. Imaging Enhancement on Deep Seismic Reflection with Petrel and Ocean Working Environment

    NASA Astrophysics Data System (ADS)

    Yu, P.; Huang, D.; Feng, X.; Li, L.; Liu, W.; Wang, Y.; Zhao, Q.

    2011-12-01

    SinoProbe has been initiated to enhance understanding of earth deep structure, resources and geological disasters forecasting throughout Chinese continent. Besides traditional deep exploration methods, various state-of-the-art technologies have been carried out in order to acquire data and jointly utilize all possible information reflecting deep crust and mantle structures and evolution.Petrel, a powerful software application developed by Schlumberger, has been successfully applied to the O&G industry. It is now a complete seismic-to-simulation application for 3D and 2D seismic interpretation. However, it has a great potential to allow the user to extend utilization with multiple types of data sets to deal with much deeper geophysical information. Petrel all-in-one concept, that functionally comprises of massive data integration, multiple domains experts participation and 3D geological object-oriented etc., will come benefit to the deep earth study. Currently, there is no special tool designed for this purpose so that Petrel is required to extend its potential to cope with not only O&G area but also a larger area with unique requests of deeper objects.Ocean, a software framework for Petrel, provides an open development environment offering seamless integration of developer intellectual contribution to the Petrel mainstream workflow. It is able to accelerate the development and deployment of user's Petrel-like workflows to resolve complex problems. It can be implemented by means of plug-ins utilities although there is additional challenge to write a robust code with Ocean framework. Deep seismic reflection profiling is a well recognized technique to reveal the fine structure of lithosphere. Moreover, it can perform a significant role for prospective evaluation of O&G and mineral resources, and geological disasters. Its near-vertical deep seismic reflection method can enhance broad band seismic observations for imaging of the deep crust and continental geodynamics

  20. SSL: Signal Similarity-Based Localization for Ocean Sensor Networks

    PubMed Central

    Chen, Pengpeng; Ma, Honglu; Gao, Shouwan; Huang, Yan

    2015-01-01

    Nowadays, wireless sensor networks are often deployed on the sea surface for ocean scientific monitoring. One of the important challenges is to localize the nodes’ positions. Existing localization schemes can be roughly divided into two types: range-based and range-free. The range-based localization approaches heavily depend on extra hardware capabilities, while range-free ones often suffer from poor accuracy and low scalability, far from the practical ocean monitoring applications. In response to the above limitations, this paper proposes a novel signal similarity-based localization (SSL) technology, which localizes the nodes’ positions by fully utilizing the similarity of received signal strength and the open-air characteristics of the sea surface. In the localization process, we first estimate the relative distance between neighboring nodes through comparing the similarity of received signal strength and then calculate the relative distance for non-neighboring nodes with the shortest path algorithm. After that, the nodes’ relative relation map of the whole network can be obtained. Given at least three anchors, the physical locations of nodes can be finally determined based on the multi-dimensional scaling (MDS) technology. The design is evaluated by two types of ocean experiments: a zonal network and a non-regular network using 28 nodes. Results show that the proposed design improves the localization accuracy compared to typical connectivity-based approaches and also confirm its effectiveness for large-scale ocean sensor networks. PMID:26610520

  1. SSL: Signal Similarity-Based Localization for Ocean Sensor Networks.

    PubMed

    Chen, Pengpeng; Ma, Honglu; Gao, Shouwan; Huang, Yan

    2015-01-01

    Nowadays, wireless sensor networks are often deployed on the sea surface for ocean scientific monitoring. One of the important challenges is to localize the nodes' positions. Existing localization schemes can be roughly divided into two types: range-based and range-free. The range-based localization approaches heavily depend on extra hardware capabilities, while range-free ones often suffer from poor accuracy and low scalability, far from the practical ocean monitoring applications. In response to the above limitations, this paper proposes a novel signal similarity-based localization (SSL) technology, which localizes the nodes' positions by fully utilizing the similarity of received signal strength and the open-air characteristics of the sea surface. In the localization process, we first estimate the relative distance between neighboring nodes through comparing the similarity of received signal strength and then calculate the relative distance for non-neighboring nodes with the shortest path algorithm. After that, the nodes' relative relation map of the whole network can be obtained. Given at least three anchors, the physical locations of nodes can be finally determined based on the multi-dimensional scaling (MDS) technology. The design is evaluated by two types of ocean experiments: a zonal network and a non-regular network using 28 nodes. Results show that the proposed design improves the localization accuracy compared to typical connectivity-based approaches and also confirm its effectiveness for large-scale ocean sensor networks. PMID:26610520

  2. Effect of the 'Vesulian events' on the foraminifers and ostracods in the Tethyan oceanic environment

    NASA Astrophysics Data System (ADS)

    Görög, Ágnes; Wernli, Roland; Tóth, Emőke

    2014-05-01

    In the north-western Tethys, at the Early/Late Bajocian boundary the 'Vesulian Unconformity' can be recognized as a result of carbonate crisis caused by transgression, culminating in the late Niortense -early Garantiana zones, followed by cooling and sudden regression. Later, in the Zigzag and Progracilis zones there was a regression causing also first-order crisis in the ammonite fauna. Up to know only the early Bajocian (BARBIERI, 1964; MONOSTORI, 1995; WERNLI and GöRöG, 1999, 2000) and middle - late Bathonian (GöRöG and WERNLI, 2002) microfauna of the Tethyan oceanic realm were studied and we have no information about late Bajocian -early Bathonian interval. The study of the foraminifera and ostracoda fauna from succession of Gyenespuszta, Bakony Mts, Hungary fill the gap of the records about these ages. The succession consists of ammonitico rosso type limestones, deposited on a submarine high. Despite the heavy condensation a relatively complete stratigraphic sequence (4 m) from the late Bajocian Humphresianum Zone up to late Bathonian Retrocostatum Zone could be identified based on ammonites (GALáCZ, 1970, 1980), which is unique in the Tethys. From each of the 18 beds, thin sections were made for microfauna and microfacies studies and the microfauna were extracted by pure acetic acid. In the ostracoda fauna is relative poor (13 species) consisting of smooth bairdids, Paracypris, Bythocypris, Pontocyprella and Polycope species. Several are known only from the Tethyan oceanic environment, while others occurred also in deep sublittoral - bathyal zone of the epicontinental areas. In the foraminifera fauna 55 benthic and 6 plankton protoglobigerinids (Globuligerina oxfordiana, G. bathoniana, G. aff. bathoniana, Conoglobigerina? aff. dagestanica, C.? avariformis forma alta and sphaerica) could be identified. The fauna differs from the epicontinental ones basically in the ratio of the different forms. Throughout the succession the protoglobigerinids (10

  3. An ENSO prediction approach based on ocean conditions and ocean-atmosphere coupling

    NASA Astrophysics Data System (ADS)

    Tseng, Yu-heng; Hu, Zeng-Zhen; Ding, Ruiqiang; Chen, Han-ching

    2016-05-01

    A simple statistical model for the El Niño-Southern Oscillation (ENSO) prediction is derived based on the evolution of the ocean heat condition and the oceanic Kelvin wave propagation associated with westerly wind events (WWEs) and easterly wind surges (EWSs) in the tropical Pacific. The multivariate linear regression model solely relies on the pentad thermocline depth anomaly evolution in 25 days along with the zonal surface wind modulation. It successfully hindcasts all ENSOs except for the 2000/01 La Niña, using the pentad (or monthly) mean tropical atmosphere ocean array data since 1994 with an averaged skill (measured by anomaly correlation) of 0.62 (or 0.67) with a 6-month lead. The exception is mainly due to the long-lasting cold sea surface temperature anomalies in the subtropics resulting from the strong 1998/99 La Niña, even though the tropical warm water volume (WWV) had rebounded and turned phases after 2000. We also note that the hindcast skill is comparable using pentad or monthly mean NCEP global ocean data assimilation system data for the same time period. The hindcast skill of the proposed statistical model is better than that based on the WWV index in terms of the monthly correlation, normalized RMSEs and ENSO occurrences, which suggest that including the evolution of the subsurface ocean temperature anomaly and the WWEs/EWSs in the central tropical Pacific can enhance the ability to predict ENSO. The hindcast skill is also comparable to the predictions using other dynamical and statistical models, indicating that these processes are the keys to ENSO development. The dynamics behind the statistical model are consistent with the physical processes of ENSO development as follows: the tropical WWV resulting from the interannually-varying meridional subtropical cell transport provides a sufficient heat source. When the seasonal phase lock of ocean-atmosphere coupling triggers the positive (negative) zonal wind anomaly in boreal summer and fall, an

  4. An Adaptive Particle Filtering Approach to Tracking Modes in a Varying Shallow Ocean Environment

    SciTech Connect

    Candy, J V

    2011-03-22

    The shallow ocean environment is ever changing mostly due to temperature variations in its upper layers (< 100m) directly affecting sound propagation throughout. The need to develop processors that are capable of tracking these changes implies a stochastic as well as an 'adaptive' design. The stochastic requirement follows directly from the multitude of variations created by uncertain parameters and noise. Some work has been accomplished in this area, but the stochastic nature was constrained to Gaussian uncertainties. It has been clear for a long time that this constraint was not particularly realistic leading a Bayesian approach that enables the representation of any uncertainty distribution. Sequential Bayesian techniques enable a class of processors capable of performing in an uncertain, nonstationary (varying statistics), non-Gaussian, variable shallow ocean. In this paper adaptive processors providing enhanced signals for acoustic hydrophonemeasurements on a vertical array as well as enhanced modal function estimates are developed. Synthetic data is provided to demonstrate that this approach is viable.

  5. Temperature and depth profiles recorded during dives of elephant seals reflect distinct ocean environments

    NASA Astrophysics Data System (ADS)

    Campagna, Claudio; Rivas, Andrés L.; Marin, M. Rosa

    2000-03-01

    Foraging adult southern elephant seals, Mirounga leonina, from Penı´nsula Valdés, Argentina, dive continuously while travelling across the continental shelf towards deep waters of the SW Atlantic. This study attempted to identify distinct ocean environments encountered by these seals during foraging migrations based on bathymetric and water temperature profiles, and to interpret these profiles in terms of mixing and systems of currents. Depth and water temperature were obtained with data loggers carried by 14 diving adult animals during spring (October-December) and summer (February-March) months. Dive depths allowed us to unmistakably differentiate extensive areas of the SW Atlantic: the Patagonian shelf, shelf slope and open waters of the Argentine Basin. Water temperature profiles added further details to the latter general oceanographic areas, and could be related to large-scale oceanographic processes that led to different water column structures. Temperature data reflected the mixing effects of winds and tides in coastal waters, the formation of a thermocline in mid-shelf areas, the northward flow of the sub-antartic Malvinas Current at the edge of the shelf, and the effect of the subtropical Brazil Current further east over deep off-shelf waters. Some of these distinct areas are known for their enhanced primary production associated with frontal systems. The study shows that elephant seals could be useful, low-cost platforms to obtain oceanographic data. Studies that require extensive sampling of physical variables in large areas over long periods of time would benefit from this approach, pending on more precise and frequent locations of animals at sea.

  6. Passive localization in ocean acoustics: A model-based approach

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1995-09-01

    A model-based approach is developed to solve the passive localization problem in ocean acoustics using the state-space formulation for the first time. It is shown that the inherent structure of the resulting processor consists of a parameter estimator coupled to a nonlinear optimization scheme. The parameter estimator is designed using the model-based approach in which an ocean acoustic propagation model is used in developing the model-based processor required for localization. Recall that model-based signal processing is a well-defined methodology enabling the inclusion of environmental (propagation) models, measurement (sensor arrays) models, and noise (shipping, measurement) models into a sophisticated processing algorithm. Here the parameter estimator is designed, or more appropriately the model-based identifier (MBID) for a propagation model developed from a shallow water ocean experiment. After simulation, it is then applied to a set of experimental data demonstrating the applicability of this approach. {copyright} {ital 1995} {ital Acoustical} {ital Society} {ital of} {ital America}.

  7. Convective available potential energy in the environment of oceanic and continental clouds: Correction and comments

    NASA Technical Reports Server (NTRS)

    Lucas, Christopher; Zipser, Edward J.; Lemone, Margaret A.

    1994-01-01

    In 1980, Zipser and LeMone estimated the convective available potential energy (CAPE) for the Thunderstorm Project cumulonimbus environment to be about 3000 J per kg. By assuming the most adiabat reported by Byers and Braham (1949) to be that of an undilute parcel rather than a reference moist adiabat, a significant error was introduced. On the basis of recent calculations made under similar conditions in Oklahoma and Florida, CAPE is now estimated to be considerably lower. These lower CAPE estimates shed doubt on the suggestion that differences in CAPE account for differences in the vertical velocities in convective updrafts over land and over the ocean.

  8. Radioactive pollution: Oean environments. (Latest citations from Oceanic abstracts). Published Search

    SciTech Connect

    1995-02-01

    This bibliography contains citations concerning radioactive pollution of the marine environment. Distrubutions of radionuclides that indicate artificial radioactive contamination are discussed including iodine-131, various uranium isotopes, Cesium-137, Cobalt-60, Strontium-90, Ruthenium-160, and plutonium isotopes. Ecosystems considered include coral reefs and atolls, planktonic zones in the open ocean, salt marshes, estuaries, coastal waters, and the Mediterranean Sea. Sources of radioactive contamination examined include atomic bomb blasts, fossil fuel combustion, radioactive waste disposal, and nuclear accidents. Experimental simulation of radionuclide transport in marine biota is included. (Contains a minimum of 168 citations and includes a subject term index and title list.)

  9. Search strategy in a complex and dynamic environment (the Indian Ocean case)

    NASA Astrophysics Data System (ADS)

    Loire, Sophie; Arbabi, Hassan; Clary, Patrick; Ivic, Stefan; Crnjaric-Zic, Nelida; Macesic, Senka; Crnkovic, Bojan; Mezic, Igor; UCSB Team; Rijeka Team

    2014-11-01

    The disappearance of Malaysia Airlines Flight 370 (MH370) in the early morning hours of 8 March 2014 has exposed the disconcerting lack of efficient methods for identifying where to look and how to look for missing objects in a complex and dynamic environment. The search area for plane debris is a remote part of the Indian Ocean. Searches, of the lawnmower type, have been unsuccessful so far. Lagrangian kinematics of mesoscale features are visible in hypergraph maps of the Indian Ocean surface currents. Without a precise knowledge of the crash site, these maps give an estimate of the time evolution of any initial distribution of plane debris and permits the design of a search strategy. The Dynamic Spectral Multiscale Coverage search algorithm is modified to search a spatial distribution of targets that is evolving with time following the dynamic of ocean surface currents. Trajectories are generated for multiple search agents such that their spatial coverage converges to the target distribution. Central to this DSMC algorithm is a metric for the ergodicity.

  10. Environmental Risk Evaluation System – An Approach to Ranking Risk of Ocean Energy Development on Coastal and Estuarine Environments

    SciTech Connect

    Copping, Andrea E.; Hanna, Luke A.; Van Cleve, Frances B.; Blake, Kara M.; Anderson, Richard M.

    2015-01-01

    Deployment and operation of ocean energy devices does not represent the first foray into industrialization of the oceans; shipping, nearshore development, waste disposal, subsea mining, oil and gas extraction, and large-scale commercial fishing all coexist in various states of equilibrium with the marine environment. In most cases these industries were developed without a clear understanding of the likely outcomes of large-scale development. In virtually every country where the harvest of ocean energy is emerging, regulators and stakeholders require that the industry examine potential effects of devices, minimize the footprint of effects, and provide management measures that either avoid the impacts or mitigate to further reduce the residual impacts. The ERES analysis is based on scenarios that are consistent with sequences of events that lead to adverse impacts, distinguishing between episodic, intermittent, and chronic risks. In the context of ocean energy development, an episodic scenario might involve the exceedingly rare but potentially devastating event of an oil spill from vessels caused by the presence of the device, while vulnerable receptors are present; understanding the risk of such a scenario involves determining the probability of the occurrence by examining factors such as the petroleum content of ocean energy devices, the vessel traffic volume and the proximity of shipping lanes to the ocean energy devices, the reliability of the control measures to avoid an episodic event, and the likely presence of seabirds, marine mammals, or fish that may be affected by oil. In contrast, chronic risk scenarios involve events or circumstances that are continuous, so that risk characterization involves assessing only the severity of the consequences. An example of a chronic risk scenario might be the toxicity to marine organisms due to low-level chemical releases from anti-biofouling paints and coatings that may be used on devices, and the effect that the level of

  11. Identifying rhodamine dye plume sources in near-shore oceanic environments by integration of chemical and visual sensors.

    PubMed

    Tian, Yu; Kang, Xiaodong; Li, Yunyi; Li, Wei; Zhang, Aiqun; Yu, Jiangchen; Li, Yiping

    2013-01-01

    This article presents a strategy for identifying the source location of a chemical plume in near-shore oceanic environments where the plume is developed under the influence of turbulence, tides and waves. This strategy includes two modules: source declaration (or identification) and source verification embedded in a subsumption architecture. Algorithms for source identification are derived from the moth-inspired plume tracing strategies based on a chemical sensor. The in-water test missions, conducted in November 2002 at San Clemente Island (California, USA) in June 2003 in Duck (North Carolina, USA) and in October 2010 at Dalian Bay (China), successfully identified the source locations after autonomous underwater vehicles tracked the rhodamine dye plumes with a significant meander over 100 meters. The objective of the verification module is to verify the declared plume source using a visual sensor. Because images taken in near shore oceanic environments are very vague and colors in the images are not well-defined, we adopt a fuzzy color extractor to segment the color components and recognize the chemical plume and its source by measuring color similarity. The source verification module is tested by images taken during the CPT missions. PMID:23507823

  12. Identifying Rhodamine Dye Plume Sources in Near-Shore Oceanic Environments by Integration of Chemical and Visual Sensors

    PubMed Central

    Tian, Yu; Kang, Xiaodong; Li, Yunyi; Li, Wei; Zhang, Aiqun; Yu, Jiangchen; Li, Yiping

    2013-01-01

    This article presents a strategy for identifying the source location of a chemical plume in near-shore oceanic environments where the plume is developed under the influence of turbulence, tides and waves. This strategy includes two modules: source declaration (or identification) and source verification embedded in a subsumption architecture. Algorithms for source identification are derived from the moth-inspired plume tracing strategies based on a chemical sensor. The in-water test missions, conducted in November 2002 at San Clemente Island (California, USA) in June 2003 in Duck (North Carolina, USA) and in October 2010 at Dalian Bay (China), successfully identified the source locations after autonomous underwater vehicles tracked the rhodamine dye plumes with a significant meander over 100 meters. The objective of the verification module is to verify the declared plume source using a visual sensor. Because images taken in near shore oceanic environments are very vague and colors in the images are not well-defined, we adopt a fuzzy color extractor to segment the color components and recognize the chemical plume and its source by measuring color similarity. The source verification module is tested by images taken during the CPT missions. PMID:23507823

  13. Mean Upper-Ocean Circulation of the Southern Hemisphere Oceans Based on Goce Data

    NASA Astrophysics Data System (ADS)

    Menezes, V. V.; Bingham, R. J.; Vianna, M. L.; Phillips, H. E.

    2012-12-01

    One of the main goals of the Gravity and steady-state Ocean Circulation Explorer (GOCE) satellite mission launched in 2009 is to improve the previous estimates of the global ocean circulation structures determined from Mean Dynamic Topographies (MDTs). Recently published studies suggest that the GOCE-based MDTs and their respective mean geostrophic circulation fields (MGCs) are superior to those obtained from GRACE (Gravity Recovery and Climate Experiment)-only data. These studies focus mostly on the circulation of the North Atlantic and North Pacific oceans with emphasis on the strong western boundary current systems. In contrast, no detailed assessment has yet been made to determine the impact of the GOCE models in the southern hemisphere (SH) upper-ocean circulation especially in the subtropical region. It is generally recognized that the SH circulation is still not well established even at large scales, and the new GOCE and GRACE products can contribute to increase our understanding of the dominant currents in these regions, which may have even greater impact on the global climate than the NH counterparts. In the present work, we compute five global GOCE-derived MDTs with a 0.25 x 0.25 degree spatial grid based on three GOCE geoid models (TIM3, GOCO02S, GOCO3S) and three mean sea surfaces (CLS01, CLS11, DTU10) using the standard spectral approach (MSS minus Geoid). These MDTs do not have the well-known large-amplitude striation-type noise that plagued all of the GRACE-only MDTs with he same resolution, but still present commission errors which are filptered out with Singular Spectrum Analysis methods. Additionally, the MGCs were calculated by use of a Anderssen-Hegland averaging scheme for estimation of derivatives, which is able to filter out the well-known high amplitude noise caused by standard finite-difference methods. Comparisons with previous GRACE-only MGCs show that GOCE permits retrieval of currents with much higher intensities (e.g. the Agulhas

  14. Ray-based blind deconvolution in ocean sound channels.

    PubMed

    Sabra, Karim G; Song, Hee-Chun; Dowling, David R

    2010-02-01

    This letter describes a ray-based blind deconvolution technique for ocean sound channels that produces broadband estimates of the source-to-array impulse response and the original source waveform from array-measured signals corrupted by (unknown) multipath propagation. The technique merely requires elementary knowledge of array geometry and sound speed at the array location. It is based on identifying a ray arrival direction to separate source waveform and acoustic-propagation phase contributions to the received signals. This technique successfully decoded underwater telecommunication sequences in the bandwidth 3-4 kHz that were broadcast 4 km in a 120-m-deep ocean sound channel without a-priori knowledge of sound channel characteristics. PMID:20136177

  15. Spacecraft VHF Radio Propagation Analysis in Ocean Environments Including Atmospheric Effects

    NASA Technical Reports Server (NTRS)

    Hwu, Shian; Moreno, Gerardo; Desilva, Kanishka; Jih, CIndy

    2010-01-01

    The Communication Systems Simulation Laboratory (CSSL) at the National Aeronautics and Space Administration (NASA)/Johnson Space Center (JSC) is tasked to perform spacecraft and ground network communication system simulations. The CSSL has developed simulation tools that model spacecraft communication systems and the space/ground environment in which they operate. This paper is to analyze a spacecraft's very high frequency (VHF) radio signal propagation and the impact to performance when landing in an ocean. Very little research work has been done for VHF radio systems in a maritime environment. Rigorous Radio Frequency (RF) modeling/simulation techniques were employed for various environmental effects. The simulation results illustrate the significance of the environmental effects on the VHF radio system performance.

  16. Broadband Processing in a Noisy Shallow Ocean Environment: A Particle Filtering Approach

    DOE PAGESBeta

    Candy, J. V.

    2016-04-14

    Here we report that when a broadband source propagates sound in a shallow ocean the received data can become quite complicated due to temperature-related sound-speed variations and therefore a highly dispersive environment. Noise and uncertainties disrupt this already chaotic environment even further because disturbances propagate through the same inherent acoustic channel. The broadband (signal) estimation/detection problem can be decomposed into a set of narrowband solutions that are processed separately and then combined to achieve more enhancement of signal levels than that available from a single frequency, thereby allowing more information to be extracted leading to a more reliable source detection.more » A Bayesian solution to the broadband modal function tracking, pressure-field enhancement, and source detection problem is developed that leads to nonparametric estimates of desired posterior distributions enabling the estimation of useful statistics and an improved processor/detector. In conclusion, to investigate the processor capabilities, we synthesize an ensemble of noisy, broadband, shallow-ocean measurements to evaluate its overall performance using an information theoretical metric for the preprocessor and the receiver operating characteristic curve for the detector.« less

  17. Descriptive and grade-tonnage models of volcanogenic manganese deposits in oceanic environments; a modification

    USGS Publications Warehouse

    Mosier, Dan L.; Page, Norman J

    1988-01-01

    Four types of volcanogenic manganese deposits, distinguished on the basis of geologic, geochemical, and geophysical characteristics, appear to result from a combination of volcanic and hydrothermal processes related to hot-spring activity in oceanic environments. We compare these four desposit types, here called the Franciscan, Cuban, Olympic Peninsula, and Cyprus, with respect to host rocks, associated rocks, minerals, deposit shape, dimensions, volume, tonnage, grade, and mineral-deposit density (number of deposits per unit area). Franciscan-type deposits occur in obducted oceanic ridge and backarc marginal-basin environments, are associated with chert, shale, and graywacke aroun the margins of mafic volcanic centers, and have a median tonnage of 450 t and median grades of 36 weight percent Mn and less than 5.1 weight percent Fe. Cuban-type deposits occur in island-arc environments, are associated with tuff and limestone around domal structures or intrusions inferred to be volcanic centers, and have a median tonnage of 6,400 t and median grades of 39 weight percent Mn and less than 4.4 weight percent Fe. Olympic Peninsula-type deposits occur in obducted oceanic midplate settings, are associated with argillaceous limestone, argillite, and graywacke around mafic volcanic centers (seamounts or islands), and have a median tonnage of 340 t and median grades of 35 weight percent Mn and less than 6.5 weight percent Fe. Cyprus-type deposits occur in the same tectonic environments as Franciscan type but are associated with basalt, marl, chalk, silt, and chert off the ridge-axis position and have a median tonnage of 41,000 t and median grades of 33 weight percent Fe and 8 weight percent Mn. All these deposits are thin ellipsoids, concordant to the host rocks, but Cyprus-and Cuban-type deposits are larger than Franciscan- and Olympic Peninsula-type deposits. Except for Cyprus-type deposits, which are manganiferous iron (umber) deposits composed of hydrated iron and

  18. A Web-Based Climatology of Global Ocean Winds

    NASA Astrophysics Data System (ADS)

    Risien, C. M.; Chelton, D. B.; Hodges, M. K.

    2004-12-01

    A climatology of winds over the global ocean on a 0.5° x 0.5° grid is under development based on five-years of measurements from the SeaWinds scatterometer. The SeaWinds instrument was launched on 19 June 1999 onboard the QuikSCAT satellite. SeaWinds is an active microwave radar that, using electromagnetic backscatter from the wind roughened ocean surface, measures vector winds with an accuracy equivalent to well-calibrated buoy observations. This five-year climatology is a web-based interactive atlas from which users can retrieve wind statistics, both in tabular and graphic form, for any particular region of interest. The global coverage of the scatterometer data provides valuable information about the wind statistics in the many regions of the world ocean that are sparsely sampled by ships and buoys. One of the anticipated uses of this climatology will be presented via a case study of the NOAA/HAZMAT response to a 2001 oil spill that resulted from the grounding of the tanker "Jessica" at the entrance to Puerto Baquerizo Moreno, in Wreck Bay, on San Cristóbal island, Galápagos.

  19. Spatio-temporal variability of aerosols in the tropics relationship with atmospheric and oceanic environments

    NASA Astrophysics Data System (ADS)

    Zuluaga-Arias, Manuel D.

    2011-12-01

    Earth's radiation budget is directly influenced by aerosols through the absorption of solar radiation and subsequent heating of the atmosphere. Aerosols modulate the hydrological cycle indirectly by modifying cloud properties, precipitation and ocean heat storage. In addition, polluting aerosols impose health risks in local, regional and global scales. In spite of recent advances in the study of aerosols variability, uncertainty in their spatio-temporal distributions still presents a challenge in the understanding of climate variability. For example, aerosol loading varies not only from year to year but also on higher frequency intraseasonal time scales producing strong variability on local and regional scales. An assessment of the impact of aerosol variability requires long period measurements of aerosols at both regional and global scales. The present dissertation compiles a large database of remotely sensed aerosol loading in order to analyze its spatio-temporal variability, and how this load interacts with different variables that characterize the dynamic and thermodynamic states of the environment. Aerosol Index (AI) and Aerosol Optical Depth (AOD) were used as measures of the atmospheric aerosol load. In addition, atmospheric and oceanic satellite observations, and reanalysis datasets is used in the analysis to investigate aerosol-environment interactions. A diagnostic study is conducted to produce global and regional aerosol satellite climatologies, and to analyze and compare the validity of aerosol retrievals. We find similarities and differences between the aerosol distributions over various regions of the globe when comparing the different satellite retrievals. A nonparametric approach is also used to examine the spatial distribution of the recent trends in aerosol concentration. A significant positive trend was found over the Middle East, Arabian Sea and South Asian regions strongly influenced by increases in dust events. Spectral and composite analyses

  20. Research on strategy marine noise map based on i4ocean platform: Constructing flow and key approach

    NASA Astrophysics Data System (ADS)

    Huang, Baoxiang; Chen, Ge; Han, Yong

    2016-02-01

    Noise level in a marine environment has raised extensive concern in the scientific community. The research is carried out on i4Ocean platform following the process of ocean noise model integrating, noise data extracting, processing, visualizing, and interpreting, ocean noise map constructing and publishing. For the convenience of numerical computation, based on the characteristics of ocean noise field, a hybrid model related to spatial locations is suggested in the propagation model. The normal mode method K/I model is used for far field and ray method CANARY model is used for near field. Visualizing marine ambient noise data is critical to understanding and predicting marine noise for relevant decision making. Marine noise map can be constructed on virtual ocean scene. The systematic marine noise visualization framework includes preprocessing, coordinate transformation interpolation, and rendering. The simulation of ocean noise depends on realistic surface. Then the dynamic water simulation gird was improved with GPU fusion to achieve seamless combination with the visualization result of ocean noise. At the same time, the profile and spherical visualization include space, and time dimensionality were also provided for the vertical field characteristics of ocean ambient noise. Finally, marine noise map can be published with grid pre-processing and multistage cache technology to better serve the public.

  1. Fatigue crack growth of Ti-6Al-4V-0.1Ru (ELI grade) in ocean environments

    NASA Astrophysics Data System (ADS)

    Langoy, Morten Andre

    1999-11-01

    This study of fatigue crack growth rates found that Ti-6Al-4V-0.1Ru alloy seamless pipe in beta transformed/annealed condition is well suited for dynamically loaded risers, which transport the reservoir fluid (oil and gas) from the well to the vessel, and promises significant economic benefits can be realized by employing the material in this application. The tested ocean environments did not detrimentally affect crack growth rates. The material was studied in two conditions: as-received (i.e., the parent material) and cold rolled (simulating the effect of coiling and reeling). The effect of different combinations of loading and environment on fatigue crack growth rates of the parent and cold rolled materials were studied systematically using a design of experiments (DOE) approach. Different combinations of temperature, load frequency, R (sigmamin/sigmamax of the fatigue cycle), pre-strain (cold work), and environment (laboratory air and aerated and deaerated simulated ocean water) were used in the study. The observed fatigue crack growth rates ranged from 4 x 10 -10 to 1 x 10-6 m/cycle and the investigated DeltaK's (stress intensity ranges) ranged from 7 to 45 MPa√m. Fatigue crack growth rates are not substantially higher in ocean environments than in air, but the differences appear to be real. Cold work (5% reduction in thickness by rolling) reduces fatigue crack growth rates (compared to the parent material) at intermediate and high DeltaK by a factor of two. Microstructure, fracture surfaces, and crack path also were related to testing conditions. Fracture surfaces reveal a change of morphology from features associated with microstructure-sensitive crack propagation (cyclic cleavage) to features (striations) linked with structure-insensitive (continuum-mode) growth. Contrary to expectations based on anecdotal accounts, crack branching is observed at the center of the samples regardless of DeltaK or other parameters and also on the outer surfaces of the

  2. Accumulation of organic matter in Cretaceous oxygen-deficient depositional environments in the central Pacific Ocean

    USGS Publications Warehouse

    Dean, W.E.; Claypool, G.E.; Thide, J.

    1984-01-01

    and intercepts of C-S regression lines however, are different for each site and all are different from regression lines for samples from modern anoxic marine sediments and from Black Sea cores. The organic-carbon-rich limestones on Hess Rise, the Mid-Pacific Mountains, and other plateaus and seamounts in the Pacific Ocean are not synchronous but do occur within the same general middle Cretaceous time period as organic-carbon-rich lithofacies elsewhere in the world ocean, particularly in the Atlantic Ocean. Strata of equivalent age in the deep basins of the Pacific Ocean are not rich in organic carbon, and were deposited in oxygenated environments. This observation, together with the evidence that the plateau sites were considerably shallower and closse to the equator during the middle Creataceous suggests that local tectonic and hydrographic conditions may have resulted in high surface-water productivity and the preservation of organic matter in an oxygen-deficient environment where an expanded mid-water oxygen minimum developed and impinged on elevated platforms and seamounts. ?? 1984.

  3. Patterns of faulting and seismicity in the mid-ocean ridge environment

    NASA Astrophysics Data System (ADS)

    Bohnenstiehl, Delwayne Roger

    Abyssal hill faults within the slow-spreading (˜20 mm/yr) mid-ocean ridge environment exhibit displacement-length ratios that are systematically larger than those observed within the fast-spreading environment (˜100 mm/yr). This can be explained by considering the importance of fault linkage in the lateral growth of abyssal hill faults and the limits imposed on maximum fault displacement by the lithospheric thickness within each setting. Within the superfast spreading environment (>140 mm/yr) of the southern East Pacific Rise (EPR), a pattern of inward-dipping master faults is observed, with smaller outward-dipping faults clustered within their hanging walls. This pattern is distinct from the more classic horst and graben morphology described on the fast-spreading northern EPR. The pattern documented on the southern EPR suggests inward-dipping master faults are more sharply curved or listric relative to their abyssal hill equivalents at fast-spreading rates. Boundary element modeling is used to examine the role of axial magma chamber inflation in generating the pattern of faulting observed along the southern EPR. An earthquake catalog derived from the detection of seismically generated T-waves is used to study the decay rate and spatial distribution of mid-ocean ridge aftershock sequences. Generally, aftershock sequences in the mid-ocean ridge setting can be well described by a modified Omori law. Decay constants (p-values) are slightly higher than those previously estimated from stacked sequences derived from the teleseismic record. Three transform fault sequences and one microplate thrust sequence exhibit p-values consistent with the global median value. There is some evidence for higher p-values associated with normal faulting mainshocks along the spreading centers. Although the June 1999 Endeavour segment sequence has been suggested previously to be of tectonic origin, the timing and distribution of earthquakes are inconsistent with the aftershock process

  4. Estimating moisture transport over oceans using space-based observations

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Wenqing, Tang

    2005-01-01

    The moisture transport integrated over the depth of the atmosphere (0) is estimated over oceans using satellite data. The transport is the product of the precipitable water and an equivalent velocity (ue), which, by definition, is the depth-averaged wind velocity weighted by humidity. An artificial neural network is employed to construct a relation between the surface wind velocity measured by the spaceborne scatterometer and coincident ue derived using humidity and wind profiles measured by rawinsondes and produced by reanalysis of operational numerical weather prediction (NWP). On the basis of this relation, 0 fields are produced over global tropical and subtropical oceans (40_N- 40_S) at 0.25_ latitude-longitude and twice daily resolutions from August 1999 to December 2003 using surface wind vector from QuikSCAT and precipitable water from the Tropical Rain Measuring Mission. The derived ue were found to capture the major temporal variability when compared with radiosonde measurements. The average error over global oceans, when compared with NWP data, was comparable with the instrument accuracy specification of space-based scatterometers. The global distribution exhibits the known characteristics of, and reveals more detailed variability than in, previous data.

  5. Pressures on the marine environment and the changing climate of ocean biogeochemistry.

    PubMed

    Rees, Andrew P

    2012-12-13

    The oceans are under pressure from human activities. Following 250 years of industrial activity, effects are being seen at the cellular through to regional and global scales. The change in atmospheric CO(2) from 280 ppm in pre-industrial times to 392 ppm in 2011 has contributed to the warming of the upper 700 m of the ocean by approximately 0.1°C between 1961 and 2003, to changes in sea water chemistry, which include a pH decrease of approximately 0.1, and to significant decreases in the sea water oxygen content. In parallel with these changes, the human population has been introducing an ever-increasing level of nutrients into coastal waters, which leads to eutrophication, and by 2008 had resulted in 245,000 km(2) of severely oxygen-depleted waters throughout the world. These changes are set to continue for the foreseeable future, with atmospheric CO(2) predicted to reach 430 ppm by 2030 and 750 ppm by 2100. The cycling of biogeochemical elements has proved sensitive to each of these effects, and it is proposed that synergy between stressors may compound this further. The challenge, within the next few decades, for the marine science community, is to elucidate the scope and extent that biological processes can adapt or acclimatize to a changing chemical and physical marine environment. PMID:23129714

  6. Deep Sea Shell Taphonomy: Interactive benthic experiments in hydrate environments of Barkley Canyon, Ocean Networks Canada.

    NASA Astrophysics Data System (ADS)

    Best, Mairi; Purser, Autun

    2015-04-01

    In order to quantify and track the rates and processes of modification of biogenic carbonate in gas hydrate environments, and their possible environmental/ecological correlates, ongoing observations of experimentally deployed specimens are being made using a remotely controlled crawler with camera and sensors. The crawler is connected to NEPTUNE Canada, an 800km, 5-node, regional cabled ocean network across the northern Juan de Fuca Plate, northeastern Pacific, part of Ocean Networks Canada. One of 15 study areas is an environment of exposed hydrate mounds along the wall of Barkley Canyon, at ˜865m water depth. This is the home of a benthic crawler developed by Jacobs University of Germany, who is affectionately known as Wally. Wally is equipped with a range of sensors including cameras, methane sensor, current meter, fluorometer, turbidity meter, CTD, and a sediment microprofiler with probes for oxygen, methane, sulphide, pH, temperature, and conductivity. In conjunction with this sensor suite, a series of experiments have been designed to assess the cycling of biogenic carbon and carbonate in this complex environment. The biota range from microbes, to molluscs, to large fish, and therefore the carbon inputs include both a range of organic carbon compounds as well as the complex materials that are "biogenic carbonate". Controlled experimental specimens were deployed of biogenic carbonate (Mytilus edulis fresh shells) and cellulose (pieces of untreated pine lumber) that had been previously well characterized (photographed, weighed, and numbered, matching valves and lumber kept as controls). Deployment at the sediment/water interface was in such a way to maximize natural burial exhumation cycles but to minimize specimen interaction. 10 replicate specimens of each material were deployed in two treatments: 1) adjacent to a natural life and death assemblage of chemosynthetic bivalves and exposed hydrate on a hydrate mound and 2) on the muddy seafloor at a distance

  7. A process-based analysis of ocean heat uptake in an AOGCM with an eddy-permitting ocean component

    NASA Astrophysics Data System (ADS)

    Kuhlbrodt, T.; Gregory, J. M.; Shaffrey, L. C.

    2015-12-01

    About 90 % of the anthropogenic increase in heat stored in the climate system is found in the oceans. Therefore it is relevant to understand the details of ocean heat uptake. Here we present a detailed, process-based analysis of ocean heat uptake (OHU) processes in HiGEM1.2, an atmosphere-ocean general circulation model with an eddy-permitting ocean component of 1/3° resolution. Similarly to various other models, HiGEM1.2 shows that the global heat budget is dominated by a downward advection of heat compensated by upward isopycnal diffusion. Only in the upper tropical ocean do we find the classical balance between downward diapycnal diffusion and upward advection of heat. The upward isopycnal diffusion of heat is located mostly in the Southern Ocean, which thus dominates the global heat budget. We compare the responses to a 4xCO2 forcing and an enhancement of the windstress forcing in the Southern Ocean. This highlights the importance of regional processes for the global ocean heat uptake. These are mainly surface fluxes and convection in the high latitudes, and advection in the Southern Ocean mid-latitudes. Changes in diffusion are less important. In line with the CMIP5 models, HiGEM1.2 shows a band of strong OHU in the mid-latitude Southern Ocean in the 4xCO2 run, which is mostly advective. By contrast, in the high-latitude Southern Ocean regions it is the suppression of convection that leads to OHU. In the enhanced windstress run, convection is strengthened at high Southern latitudes, leading to heat loss, while the magnitude of the OHU in the Southern mid-latitudes is very similar to the 4xCO2 results. Remarkably, there is only very small global OHU in the enhanced windstress run. The wind stress forcing just leads to a redistribution of heat. We relate the ocean changes at high Southern latitudes to the effect of climate change on the Antarctic Circumpolar Current (ACC). It weakens in the 4xCO2 run and strengthens in the wind stress run. The weakening is due

  8. Model-based ocean acoustic passive localization. Revision 1

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1994-06-01

    A model-based approach is developed (theoretically) to solve the passive localization problem. Here the authors investigate the design of a model-based identifier for a shallow water ocean acoustic problem characterized by a normal-mode model. In this problem they show how the processor can be structured to estimate the vertical wave numbers directly from measured pressure-field and sound speed measurements thereby eliminating the need for synthetic aperture processing or even a propagation model solution. Finally, they investigate various special cases of the source localization problem, designing a model-based localizer for each and evaluating the underlying structure with the expectation of gaining more and more insight into the general problem.

  9. The Panthalassa—a cerium-rich Atlantic-type ocean: sedimentary environments of the Tamba Group, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Musashino, Makoto

    1990-09-01

    The oceanic sediments of the Tamba Group, a part of the Japanese Paleozoic-Mesozoic accretionary prism were studied geochemically. These oceanic sediments have various REE patterns, which correspond to specific ocean floor environments. The Type II suite of the Tamba Group contains the following changes in sedimentary environment; pelagic sedimentation under the influence of hydrothermal activity or diagenetic metal accumulation (negative Ce anomaly), pelagic sedimentation in Ce- poor seawater or diagenesis under less oxic conditions (LREE > HREE or MREE > LREE ⩾ HREE pattern) and slow pelagic sedimentation under oxic conditions where authigenic metal flux from seawater resulted in a positive Ce anomaly. Different from the Type II suite, lower pelagic sediments of the Type I suite show a LREE ⩽ HREE pattern, which indicates the inflow of very fine terrigenous or volcanic materials. Cherts and siliceous shales with positive Ce anomaly are exclusively present in the upper part of chert-siliceous shale sequences in all successions of the Tamba Group. This suggests that seawater of the Panthalassa Ocean was, at least partially, enriched in Ce, resembling the modern Atlantic more than the modern Pacific Ocean. The following reasons for this enrichment are considered: (1) fluvial input from surrounding continents was substantial; (2) reductive regeneration of Ce from continental shelves was active; or (3) Ce-depleted seawater did not enter from the other "ocean".

  10. Ares I-X Ascent Base Environments

    NASA Technical Reports Server (NTRS)

    Mobley, B. L.; Bender, R. L.; Canabal, F.; Smith, Sheldon D.

    2011-01-01

    Plume induced base heating environments were measured during the flight of the NASA Constellation Ares I-X developmental launch vehicle, successfully flown on October 28, 2009. The Ares IX first stage is a four segment Space Shuttle derived booster with base consisting of a flared aft skirt, deceleration and tumble motors, and a thermal curtain surrounding the first stage 7.2 area ratio nozzle. Developmental Flight Instrumentation (DFI) consisted of radiometers, calorimeters, pressure transducers and gas temperature probes installed on the aft skirt and nozzle to measure the base environments. In addition, thermocouples were also installed between the layers of the flexible thermal curtain to provide insight into the curtain response to the base environments and to assist in understanding curtain failure during reentry. Plume radiation environment predictions were generated by the Reverse Monte Carlo (RMC) code and the convective base heating predictions utilized heritage MSFC empirical methods. These predictions were compared to the DFI data and results from the flight videography. Radiation predictions agreed with the flight measured data early in flight but gauge failures prevented high altitude comparisons. The convective environment comparisons demonstrated the need to improve the prediction methodology; particularly for low altitude, local plume recirculation. The convective comparisons showed relatively good agreement at altitudes greater than 50,000 feet.

  11. The role of ocean observatories in monitoring for potential effects of man-made sound on the marine environment

    NASA Astrophysics Data System (ADS)

    Bradley, David L.; D'Spain, Gerald L.; Miller, James H.; Frisk, George V.

    2005-04-01

    An important question is whether or not man-made sounds have an adverse long-term impact on the ocean environment. Clear evidence exists that an impact has occurred on some individual animals in a few cases. However, according to the 2003 National Academy of Sciences report, the degree of impact on any marine mammal population or on ocean ecosystems as a whole is unknown. An essential component of an approach to addressing this question is an ocean noise/marine ecosystem monitoring system. The monitoring regions should be global in extent and include biologically sensitive areas. The effort should be sustained so that long-term trends in ocean noise levels can be evaluated. An important aspect of the data collection effort is the type and quality of ancillary information. Ancillary data on the marine ecosystems allows determination of any impacts and data on the sources of marine noise and marine environmental properties which are required to develop metrics for evaluating and predicting the characteristics of the noise field. The ocean observatory system presently being contemplated could play an important role in establishing an ocean noise monitoring capability. [Work supported through the National Ocean Partnership Program, with sponsorship from ONR, NOAA, NSF, and USGS.

  12. Oceans and Coasts. Teacher's Guide to World Resources. Comprehensive Coursework on the Global Environment.

    ERIC Educational Resources Information Center

    Snyder, Sarah A.

    This teacher's guide presents teaching suggestions and presentation materials about the world's oceans and the important role humans play in maintaining the life and health of the oceans. The lesson is divided into five parts and can be taught in one class period or divided into segments. Student handouts include: (1) "Facts about Oceans and…

  13. Ocean interactions with the base of Amery Ice Shelf, Antarctica

    NASA Astrophysics Data System (ADS)

    Hellmer, Hartmut H.; Jacobs, Stanley S.

    1992-12-01

    Using a two-dimensional ocean thermohaline circulation model, we varied the cavity shape beneath Amery Ice Shelf in an attempt to reproduce the 150-m-thick marine ice layer observed at the "G1" ice core site. Most simulations caused melting rates which decrease the ice thickness by as much as 400 m between grounding line and G1, but produce only minor accumulation at the ice core site and closer to the ice front. Changes in the seafloor and ice topographies revealed a high sensitivity of the basal mass balance to water column thickness near the grounding line, to submarine sills, and to discontinuities in ice thickness. Model results showed temperature/salinity gradients similar to observations from beneath other ice shelves where ice is melting into seawater. Modeled outflow characteristics at the ice front are in general agreement with oceanographic data from Prydz Bay. A freshwater flux across the grounding line, derived from melting beneath the grounded ice sheet, would have to be anomalously large to produce the basal marine ice layer and account for the Ice Shelf Water outflow. We concur with Morgan's inference that the G1 core may have been taken in a basal crevasse filled with marine ice. This ice is formed from water cooled by ocean/ice shelf interactions along the interior ice shelf base.

  14. gpuPOM: a GPU-based Princeton Ocean Model

    NASA Astrophysics Data System (ADS)

    Xu, S.; Huang, X.; Zhang, Y.; Fu, H.; Oey, L.-Y.; Xu, F.; Yang, G.

    2014-11-01

    Rapid advances in the performance of the graphics processing unit (GPU) have made the GPU a compelling solution for a series of scientific applications. However, most existing GPU acceleration works for climate models are doing partial code porting for certain hot spots, and can only achieve limited speedup for the entire model. In this work, we take the mpiPOM (a parallel version of the Princeton Ocean Model) as our starting point, design and implement a GPU-based Princeton Ocean Model. By carefully considering the architectural features of the state-of-the-art GPU devices, we rewrite the full mpiPOM model from the original Fortran version into a new Compute Unified Device Architecture C (CUDA-C) version. We take several accelerating methods to further improve the performance of gpuPOM, including optimizing memory access in a single GPU, overlapping communication and boundary operations among multiple GPUs, and overlapping input/output (I/O) between the hybrid Central Processing Unit (CPU) and the GPU. Our experimental results indicate that the performance of the gpuPOM on a workstation containing 4 GPUs is comparable to a powerful cluster with 408 CPU cores and it reduces the energy consumption by 6.8 times.

  15. Enhancing Trust in SOA Based Collaborative Environments

    NASA Astrophysics Data System (ADS)

    Boursas, Latifa; Bourimi, Mohamed; Hommel, Wolfgang; Kesdogan, Dogan

    Considering trust and privacy requirements for online and collaborative distance learning environments, this paper discusses potential extensions of SOA based applications to simultaneously support authentication and authorization services, and offering mutual trust to both learners and service providers. This study shows that the security mechanisms integrated in the SOA platform can be effectively extended and correlated with a trust model.

  16. Sustainable Management of Coastal Environments Through Coupled Terrestrial-Coastal Ocean Models

    NASA Astrophysics Data System (ADS)

    Lohrenz, S. E.; Cai, W.; Tian, H.; He, R.; Xue, Z.; Fennel, K.; Hopkinson, C.; Howden, S. D.

    2012-12-01

    Changing climate and land use practices have the potential to dramatically alter coupled hydrologic-biogeochemical processes and associated movement of water, carbon and nutrients through various terrestrial reservoirs into rivers, estuaries, and coastal ocean waters. Consequences of climate- and land use-related changes will be particularly evident in large river basins and their associated coastal outflow regions. The large spatial extent of such systems necessitates a combination of satellite observations and model-based approaches coupled with targeted ground-based site studies to adequately characterize relationships among climate forcing (e.g., wind, precipitation, temperature, solar radiation, humidity, extreme weather), land use practice/land cover change, and transport of materials through watersheds and, ultimately, to coastal regions. Here, we describe a NASA Interdisciplinary Science project that employs an integrated suite of models in conjunction with remotely sensed as well as targeted in situ observations with the objectives of describing processes controlling fluxes on land and their coupling to riverine, estuarine and ocean ecosystems. The objectives of this effort are to 1) assemble and evaluate long term datasets for the assessment of impacts of climate variability, extreme weather events, and land use practices on transport of water, carbon and nitrogen within terrestrial systems and the delivery of materials to waterways and rivers; 2) using the Mississippi River as a testbed, develop and evaluate an integrated suite of models to describe linkages between terrestrial and riverine systems, transport of carbon and nutrients in the Mississippi river and its tributaries, and associated cycling of carbon and nutrients in coastal ocean waters; and 3) evaluate uncertainty in model products and parameters and identify areas where improved model performance is needed through model refinement and data assimilation. The effort employs the Dynamic Land

  17. Astronomical Ice: The Effects of Treating Ice as a Porous Media on the Dynamics and Evolution of Extraterrestrial Ice-Ocean Environments

    NASA Astrophysics Data System (ADS)

    Buffo, J.; Schmidt, B. E.

    2015-12-01

    With the prevalence of water and ice rich environments in the solar system, and likely the universe, becoming more apparent, understanding the evolutionary dynamics and physical processes of such locales is of great importance. Piqued interest arises from the understanding that the persistence of all known life depends on the presence of liquid water. As in situ investigation is currently infeasible, accurate numerical modeling is the best technique to demystify these environments. We will discuss an evolving model of ice-ocean interaction aimed at realistically describing the behavior of the ice-ocean interface by treating basal ice as a porous media, and its possible implications on the formation of astrobiological niches. Treating ice as a porous media drastically affects the thermodynamic properties it exhibits. Thus inclusion of this phenomenon is critical in accurately representing the dynamics and evolution of all ice-ocean environments. This model utilizes equations that describe the dynamics of sea ice when it is treated as a porous media (Hunke et. al. 2011), coupled with a basal melt and accretion model (Holland and Jenkins 1999). Combined, these two models produce the most accurate description of the processes occurring at the base of terrestrial sea ice and ice shelves, capable of resolving variations within the ice due to environmental pressures. While these models were designed for application to terrestrial environments, the physics occurring at any ice-water interface is identical, and these models can be used to represent the evolution of a variety of icy astronomical bodies. As terrestrial ice shelves provide a close analog to planetary ice-ocean environments, we truth test the models validity against observations of ice shelves. We apply this model to the ice-ocean interface of the icy Galilean moon Europa. We include profiles of temperature, salinity, solid fraction, and Darcy velocity, as well as temporally and spatially varying melt and

  18. Investigating the impacts of deep ocean euxinia on continental shelf environments during the Great Ordovician Biodiversification Event: did changes in global oceanic redox have any effect?

    NASA Astrophysics Data System (ADS)

    Marenco, P. J.; Marenco, K. N.; Phillips, D. E.; Garcia, E.; Toure, N.; Fullem, A.

    2013-12-01

    The Great Ordovician Biodiversification Event was one of the most important radiations in the history of animal life. In particular, the GOBE was characterized by pronounced increases in diversity within the Paleozoic and Modern Evolutionary Faunas (e.g., Droser and Finnegan, 2003). Rather than being attributable to a singular cause, a number of tectonic, ecologic, and climate-related factors are thought to have contributed to this biodiversification event (e.g., Servais et al., 2009). For example, continental shelf area during the GOBE was more extensive than at any other time during the Phanerozoic, and the availability of these warm, shallow-water, well-oxygenated environments likely influenced the radiation (e.g., Servais et al., 2009). Despite this evidence for favorable conditions, recent geochemical studies suggest that the early Paleozoic, including the Ordovician, was a time of episodic deep ocean euxinia (e.g., Gill et al., 2011, Thompson and Kah, 2012). It remains unclear how the hypothesized deep ocean euxinia may have affected the GOBE. For example, it is possible that episodic incursions of euxinic deep water onto the continental shelves may have acted to slow down the GOBE or even dampen its magnitude. On the other hand, such incursions may have accelerated the radiation by adding additional selection pressures to communities that were already adapting to new predation and substrate conditions. Alternatively, the GOBE may have proceeded without any incursions of euxinic deep water onto the continental shelves. One way to address this issue is to investigate short-term, localized redox changes in shallow marine settings. Here we present results from our ongoing investigation of redox changes in shallow-water environments from the Lower and Middle Ordovician of Utah. Specifically, we use abundances of total organic carbon (TOC) and total sulfur (TS) as localized redox proxies. We use the isotopic composition of carbonate associated sulfate (δ34SCAS

  19. Measurements of Complex Oceanic Flows, from Turbulence in the Coastal Ocean to Interaction of Zooplankton with its Local Environment

    NASA Astrophysics Data System (ADS)

    Katz, J.

    2004-03-01

    The presentation has two parts, both dealing with flow structure, turbulence and flow-particle interactions in the ocean. The first part examines PIV data obtained in the bottom boundary layer of the coastal ocean in periods when the mean currents are higher, of the same order and weaker than the wave induced motions. The energy spectra display substantial anisotropy at all scales, and the flow consists of periods of "gusts" dominated by large vortical structures, separated by periods of quiescent flows. The frequency of these gusts increases with Reynolds number, and they disappear when the currents are weak. Conditional sampling shows that the Reynolds shear stress, and as a result the shear production, are generated only during periods of gusts. When the mean flow is weak and during quiescent periods of moderate flow the shear stresses are essentially zero. Dissipation, on the other hand, occurs continuously, and increases only slightly during gust periods. The second part focuses on interactions of zooplankton with the local flow. Digital in-line holographic cinematography is used for measuring the three-dimensional trajectory of a free-swimming copepod, and simultaneously the instantaneous 3-D velocity field around this copepod. The velocity field and trajectory of particles entrained by the copepod have a recirculating pattern in the copepod's frame of reference. This pattern is caused by the copepod sinking at a rate that is lower than its terminal sinking speed, due to the propulsive force generated by its feeding current. Consequently, the copepod has to hop periodically to scan different fluid for food. Using Stokeslets to model the velocity field, the measured velocity distributions enable us to estimate the excess weight of the copepod and the propulsive force generated by its feeding appendages. Sponsored in part by the Office of Naval Research and by the National Science Foundation.

  20. Ocean acoustic signal processing: A model-based approach

    SciTech Connect

    Candy, J.V. ); Sullivan, E.J. )

    1992-12-01

    A model-based approach is proposed to solve the ocean acoustic signal processing problem that is based on a state-space representation of the normal-mode propagation model. It is shown that this representation can be utilized to spatially propagate both modal (depth) and range functions given the basic parameters (wave numbers, etc.) developed from the solution of the associated boundary value problem. This model is then generalized to the stochastic case where an approximate Gauss--Markov model evolves. The Gauss--Markov representation, in principle, allows the inclusion of stochastic phenomena such as noise and modeling errors in a consistent manner. Based on this framework, investigations are made of model-based solutions to the signal enhancement, detection and related parameter estimation problems. In particular, a modal/pressure field processor is designed that allows {ital in} {ital situ} recursive estimation of the sound velocity profile. Finally, it is shown that the associated residual or so-called innovation sequence that ensues from the recursive nature of this formulation can be employed to monitor the model's fit to the data and also form the basis of a sequential detector.

  1. VIIRS ocean color data visualization and processing with IDL-based NOAA-SeaDAS

    NASA Astrophysics Data System (ADS)

    Wang, Xiaolong; Liu, Xiaoming; Jiang, Lide; Wang, Menghua; Sun, Junqiang

    2014-11-01

    The NOAA Sea-viewing Data Analysis System (NOAA-SeaDAS) is an Interactive Data Language (IDL)-based satellite data visualization, analysis, and processing system based on the version 6.4 of the NASA's Sea-viewing Wide Field-ofview (SeaWiFS) Data Analysis System (SeaDAS) released in 2012. NOAA-SeaDAS inherited all the original functionalities of SeaDAS 6.4 and was upgraded with many new functions and new sensor supports, particularly the support of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-Orbiting Partnership (SNPP). The main goal of the NOAA-SeaDAS development is primarily in support of NOAA ocean color team's calibration and validation activities. The current version of NOAA-SeaDAS can visualize, analyze, and process VIIRS Sensor Data Records (SDR or Level-1B data) produced by the NOAA Interface Data Processing System (IDPS), ocean color Environmental Data Records (EDR or Level-2 data) produced by the NOAA Multi-Sensor Level-1 to Level- 2 (MSL12) ocean color data processing system, and Level-3 data binned or mapped from Level-2 data produced by NOAA-MSL12. NOAA-SeaDAS is currently serving an active IDL user group at NOAA and will serve other institutions and universities in the future. The goal is to allow various scientific users to visualize, analyze, and process VIIRS data from Level-1B through Level-2 and Level-3. In addition, NOAA-SeaDAS can also visualize satellite images from the Korean Geostationary Ocean Color Imager (GOCI), as well as many other satellite ocean color sensors, e.g., SeaWiFS, the Moderate Resolution Imaging Spectroradiometer (MODIS), etc. NOAA-SeaDAS is under constant development to create new system functionalities and enhance user experience. With constantly increasing volume in the global ocean color data archive, NOAA-SeaDAS will play an important role in support of global marine environment data analysis and various scientific applications.

  2. The polar oceans and their role in shaping the global environment

    SciTech Connect

    Johannessen, O.M.; Muench, R.D.; Overland, J.E.

    1994-12-31

    This book is a comprehensive treatment of major advances made in the past decade in understanding of the interactions between polar oceans and the local atmosphere and ocean system. Included are 38 papers discussing the circulation, dynamics and convective processes occurring in the polar oceans; its carbon cycle chemistry and biology; the paleooceanography and paleoclimate of the polar regions; the interaction between the polar ocean and the global climate, and a variety of strategies for detection of climate change in polar regions, predominantly Arctic.

  3. Salmon Migration Patterns Revealed the Temporal and Spatial Fluctuations of the Radiocesium Levels in Terrestrial and Ocean Environments

    PubMed Central

    Arai, Takaomi

    2014-01-01

    The disabling of the Fukushima Daiichi Nuclear Power Plant (F1NPP) resulted in the release of radionuclides, including 134Cs and 137Cs, into the air and the ocean. The unpredicted nuclear accident is of global concern for human health and the ecosystem. Although investigations of radionuclides in environments were performed shortly after the accident started, the temporal and spatial impacts and fluctuations on the releasing radionuclides to natural environment remain unclear. I focused on salmon, which migrate from inland to the open ocean globally, to reveal the three-year (May 2011 to February 2014) fluctuations and accumulations of 134Cs and 137Cs from terrestrial to open ocean environments after the F1NPP accident. The 134Cs and 137Cs concentrations in six salmonids exhibited lower temporal variations for three years after the F1NPP accident, suggesting that these radionuclides are widely distributed and these radionuclides remain in the natural environment globally with less convergence. The accumulation patterns were significantly different among the different salmon species. Fluvial (freshwater residence) type salmons exhibited significantly higher accumulation in 134Cs (25.3–40.2 Bq kg−1 in mean) and 137Cs (41.4–51.7 Bq kg−1 in mean) than did the anadromous (sea-run) type salmons (0.64–8.03 Bq kg−1 in mean 134Cs and 0.42–10.2 Bq kg−1 in mean 137Cs) suggesting widespread contamination in terrestrial environments versus the coastal and open ocean environments. Salmonids are the most highly migratory animals and are characterised by their strong tendency to return home to their natal site for reproduction. Salmonids have a potential to be a good indicator as an effective monitoring animal. PMID:24964195

  4. Oceans and human health: Emerging public health risks n the marine environment

    PubMed Central

    Fleming, L.E.; Broad, K.; Clement, A.; Dewailly, E.; Elmir, S.; Knap, A.; Pomponi, S.A.; Smith, S.; Gabriele, H. Solo; Walsh, P.

    2008-01-01

    There has been an increasing recognition of the inter-relationship between human health and the oceans. Traditionally, the focus of research and concern has been on the impact of human activities on the oceans, particularly through anthropogenic pollution and the exploitation of marine resources. More recently, there has been recognition of the potential direct impact of the oceans on human health, both detrimental and beneficial. Areas identified include: global change, harmful algal blooms (HABs), microbial and chemical contamination of marine waters and seafood, and marine models and natural products from the seas. It is hoped that through the recognition of the inter-dependence of the health of both humans and the oceans, efforts will be made to restore and preserve the oceans. PMID:16996542

  5. MATLAB-Based VHDL Development Environment

    SciTech Connect

    Katko, K. K.; Robinson, S. H.

    2002-01-01

    The Reconfigurable Computing program at Los Alamos National Laboratory (LANL) required synthesizable VHDL Fast Fourier Transform (FFT) designs that could be quickly implemented into FPGA-based high speed Digital Signal Processing architectures. Several different FFTs were needed for the different systems. As a result, the MATLAB-Based VHDL Development Environment was developed so that with a small amount of work and forethought, arbitrarily sized FFTs with different bit-width parameters could be produced quickly from one VHDL generating algorithm. The result is highly readable VHDL that can be modified quickly via the generating function to adapt to new algorithmic requirements. Several additional capabilities are integrated into the development environment. These capabilities include a bit-true parameterized mathematical model, fixed-point design validation, test vector generation, VHDL design verification, and chip resource use estimation. LANL needed the flexibility to build a wide variety of FFTs with a quick turn around time. It was important to have an effective way of trading off size, speed and precision. The FFTs also needed to be efficiently implemented into our existing FPGA-based architecture. Reconfigurable computing systems at LANL have been designed to accept two or four inputs on each clock. This allows the data processing rate to be reduced to a more manageable speed. This approach, however, limits us from using existing FFT cores. A MATLAB-Based VHDL Development Environment (MBVDE) was created in response to our FFT needs. MBVDE provides more flexibility than is available with VHDL. The technique allows new designs to be implemented and verified quickly. In addition, analysis tools are incorporated to evaluate trade-offs. MBVDE incorporates the performance of VHDL, the fast design time of core generation, and the benefit of not having to know VHDL available with C-tools into one environment. The MBVDE approach is not a comprehensive solution, but

  6. Chitosan-based mucosal adjuvants: Sunrise on the ocean.

    PubMed

    Xia, Yufei; Fan, Qingze; Hao, Dongxia; Wu, Jie; Ma, Guanghui; Su, Zhiguo

    2015-11-01

    Mucosal vaccination, which is shown to elicit systemic and mucosal immune responses, serves as a non-invasive and convenient alternative to parenteral administration, with stronger capability in combatting diseases at the site of entry. The exploration of potent mucosal adjuvants is emerging as a significant area, based on the continued necessity to amplify the immune responses to a wide array of antigens that are poorly immunogenic at the mucosal sites. As one of the inspirations from the ocean, chitosan-based mucosal adjuvants have been developed with unique advantages, such as, ability of mucosal adhesion, distinct trait of opening the junctions to allow the paracellular transport of antigen, good tolerability and biocompatibility, which guaranteed the great potential in capitalizing on their application in human clinical trials. In this review, the state of art of chitosan and its derivatives as mucosal adjuvants, including thermo-sensitive chitosan system as mucosal adjuvant that were newly developed by author's group, was described, as well as the clinical application perspective. After a brief introduction of mucosal adjuvants, chitosan and its derivatives as robust immune potentiator were discussed in detail and depth, in regard to the metabolism, safety profile, mode of actions and preclinical and clinical applications, which may shed light on the massive clinical application of chitosan as mucosal adjuvant. PMID:26271831

  7. Continuous, high-resolution spatial mapping of water isotopes in oceanic environment using a CRDS analyzer combined with a continuous water sampler.

    NASA Astrophysics Data System (ADS)

    Kim-Hak, David; Huang, Kuan; Winkler, Renato

    2016-04-01

    The recent advancements of the laser-based technology -in particular Cavity Ring Down Spectroscopy, CRDS- gave birth to a new generation of water stable isotope analyzers that are user-friendly, compact and field deployable providing in-situ measurements. Furthermore, with last year's launch of the Continuous Water Sampler front-end, CWS, the analyzer system added two additional dimensions to liquid water measurements: real-time and continuous. These features enable the user to construct high resolution water isotope data sets through time and space. Campaigns on the Sacramento-San Joaquin River Delta with the US Geological Survey where the CWS-CRDS system was deployed onto a boat to spatially map sections of the delta, validated the CWS performance and demonstrated its durability on brackish water. The next step for the CWS is to explore oceanic applications with seawater. Early in-house laboratory experiments showed stable performance with brine waters (3% concentration). For the field experiment, we have collaborated with the China State Oceanic Administration to deploy the CWS-CRDS in oceanic environments on cruises along the costal China and Antarctic. Here, we present the results of the analysis collected onboard and compared them with discrete sampling measurements. The long-term test has also allowed us to assess the durability and expected lifetime of the CWS membrane and to recommend the proper maintenance procedure for optimum performance under oceanic conditions.

  8. Discovery of a chemosynthesis-based community in the western South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Giongo, Adriana; Haag, Taiana; Simão, Taiz L. Lopes; Medina-Silva, Renata; Utz, Laura R. P.; Bogo, Maurício R.; Bonatto, Sandro L.; Zamberlan, Priscilla M.; Augustin, Adolpho H.; Lourega, Rogério V.; Rodrigues, Luiz F.; Sbrissa, Gesiane F.; Kowsmann, Renato O.; Freire, Antonio F. M.; Miller, Dennis J.; Viana, Adriano R.; Ketzer, João M. M.; Eizirik, Eduardo

    2016-06-01

    Chemosynthetic communities have been described from a variety of deep-sea environments across the world's oceans. They constitute very interesting biological systems in terms of their ecology, evolution and biogeography, and also given their potential as indicators of the presence and abundance of consistent hydrocarbon-based nutritional sources. Up to now such peculiar biotic assemblages have not been reported for the western South Atlantic Ocean, leaving this large region undocumented with respect to the presence, composition and history of such communities. Here we report on the presence of a chemosynthetic community off the coast of southern Brazil, in an area where high-levels of methane and the presence of gas hydrates have been detected. We performed metagenomic analyses of the microbial community present at this site, and also employed molecular approaches to identify components of its benthic fauna. We conducted phylogenetic analyses comparing the components of this assemblage to those found elsewhere in the world, which allowed a historical assessment of the structure and dynamics of these systems. Our results revealed that the microbial community at this site is quite diverse, and contains many components that are very closely related to lineages previously sampled in ecologically similar environments across the globe. Anaerobic methanotrophic (ANME) archaeal groups were found to be very abundant at this site, suggesting that methane is indeed an important source of nutrition for this community. In addition, we document the presence at this site of a vestimentiferan siboglinid polychaete and the bivalve Acharax sp., both of which are typical components of deep-sea chemosynthetic communities. The remarkable similarity in biotic composition between this area and other deep-sea communities across the world supports the interpretation that these assemblages are historically connected across the global oceans, undergoing colonization from distant sites and

  9. Depositional environments and processes in Upper Cretaceous nonmarine and marine sediments, Ocean Point dinosaur locality, North Slope, Alaska

    USGS Publications Warehouse

    Phillips, R.L.

    2003-01-01

    representing interdistributary bay deposits overlie the nonmarine beds and comprise about 15 m of section. Extensive vegetated sand flats, shoals, and shallow channels overlain by shallow bay deposits (less than 7 m deep), containing storm-generated strata characterize the marginal marine beds. Abundant bioturbation and roots characterize the stratigraphic lowest bay deposits; bioturbated sediment, pelecypods, barnacles, and benthic microfossils are found in the overlying bay storm deposits. The sediments abruptly change upward from hummocky cross-stratified bay deposits to a muddy marsh deposit containing shallow organic-rich channels to prograding nonmarine to marginal marine beds. Transgressive, abundantly fossiliferous shallow-marine strata more than 13 m thick comprise the uppermost exposures at Ocean Point. The marine beds overlie nonmarine and bay strata and represent an environment dominated episodically by storms. The age of the marginal marine and marine beds is late Maastrichtian based on pollen. ?? 2003 Elsevier Ltd. All rights reserved.

  10. Feature Analysis of Ocean Waves in North Central Pacific Ocean Based ASAR Wave Spectral Data and Wave Model

    NASA Astrophysics Data System (ADS)

    Wang, Jichao; Zhang, Jie; Yang, Jungang; Meng, Junmin

    2013-01-01

    Directional Spectrum of the ocean waves could be obtained form Envisat advanced synthetic aperture radar (ASAR) wave spectral data. The wave model WAVEWATCH III (WW3) is applied to simulate the ocean wave field. Study area is 185°E-215°E and 15°N-30°N, time range is from 1 January 2008 to 31 December 2008. Based on ASAR and buoy data, the wave numerical simulation and assimilation of the north central Pacific Ocean is carried out. The validation and assessment of ASAR ocean wave spectra products is performed. The optimal interpolation (OI) algorithm is used in model WW3 for assimilating ASAR wave spectra data. Based on the result of the simulation and assimilation, mean waves direction (MWD), significant wave height (SWH) and mean wave period (MWP) are analysed. SWH and MWP are larger in winter and SWH reach to more than 2.5 meters. Seasonal change of SWH and MWP are significant.

  11. Model-based processor design for a shallow water ocean acoustic experiment

    SciTech Connect

    Candy, J.V. ); Sullivan, E.J. )

    1994-04-01

    Model-based signal processing is a well-defined methodology enabling the inclusion of environmental (propagation) models, measurement (sensor arrays) models, and noise (shipping, measurement) models into a sophisticated processing algorithm. Depending on the class of model developed from the mathematical representation of the physical phenomenology, various processors can evolve. Here the design of a space-varying, nonstationary, model-based processor (MBP) is investigated and applied to the data from a well-controlled shallow water experiment performed at Hudson Canyon. This particular experiment is very attractive for the inaugural application of the MBP because it was performed in shallow water at low frequency requiring a small number of modes. In essence, the Hudson Canyon represents a well-known ocean environment, making it ideal for this investigation. In this shallow water application, a state-space representation of the normal-mode propagation model is used. The processor is designed such that it allows [ital in] [ital situ] recursive estimation of both the pressure-field and modal functions. It is shown that the MBP can be effectively utilized to validate'' the performance of the model on noisy ocean acoustic data. In fact, a set of processors is designed, one for each source range and the results are quite good---implying that the propagation model with measured parameters adequately represents the data.

  12. Nutritional and environmental studies on an ocean-going oil tanker. 1. Thermal environment

    PubMed Central

    Collins, K. J.; Eddy, T. P.; Lee, D. E.; Swann, P. G.

    1971-01-01

    Collins, K. J., Eddy, T. P., Lee, D. E., and Swann, P. G. (1971).Brit. J. industr. Med.,28, 237-245. Nutritional and environmental studies on an ocean-going oil tanker. I. Thermal environment. Investigations were made on board a modern, air-conditioned oil tanker (S.S. Esso Newcastle) en route to the Persian Gulf in July to August 1967 in order to study thermal conditions in the working environment, and the nutritional status of the crew, and to examine the interrelationship between climate and nutritional balance. In this introductory paper an account is given of the aims and design of the experiments together with details of the environmental survey. The voyage round Africa lasted one month, with high ambient temperatures of 37·7°C dry bulb, 30·8°C wet bulb (100/87°F) occurring only on the last few days into and out of the Persian Gulf. Mean accommodation temperature was maintained in the zone of comfort throughout, and at 23·9°C (75°F) Corrected Effective Temperature (CET) in the Gulf. On a previous voyage in a tanker without air-conditioning CETs up to 31·6°C (89°F) had been recorded in the accommodation in the same ambient conditions. With exposure to high solar radiation in the Gulf, the deck officer's cabins and bridge house in the upper superstructure became uncomfortably warm (CET exceeding 26·6°C (80°F)) and in these temperatures skilled performance is likely to deteriorate. The main thermal problems in the working environment were associated with the engine and boiler rooms which were consistently 11 to 17°C (20 to 30°F) higher than ambient temperature. For personnel on watch, the levels of heat stress were high but not intolerable if advantage was taken of the air blowers. Conditions under which emergency or repair tasks were carried out in very hot engine-room spaces were examined and often found to allow only a small margin of safety. Predicted average tolerance times were deduced from the Wet Bulb Globe Temperature (WBGT) scale of

  13. Collaborative environments for capability-based planning

    NASA Astrophysics Data System (ADS)

    McQuay, William K.

    2005-05-01

    Distributed collaboration is an emerging technology for the 21st century that will significantly change how business is conducted in the defense and commercial sectors. Collaboration involves two or more geographically dispersed entities working together to create a "product" by sharing and exchanging data, information, and knowledge. A product is defined broadly to include, for example, writing a report, creating software, designing hardware, or implementing robust systems engineering and capability planning processes in an organization. Collaborative environments provide the framework and integrate models, simulations, domain specific tools, and virtual test beds to facilitate collaboration between the multiple disciplines needed in the enterprise. The Air Force Research Laboratory (AFRL) is conducting a leading edge program in developing distributed collaborative technologies targeted to the Air Force's implementation of systems engineering for a simulation-aided acquisition and capability-based planning. The research is focusing on the open systems agent-based framework, product and process modeling, structural architecture, and the integration technologies - the glue to integrate the software components. In past four years, two live assessment events have been conducted to demonstrate the technology in support of research for the Air Force Agile Acquisition initiatives. The AFRL Collaborative Environment concept will foster a major cultural change in how the acquisition, training, and operational communities conduct business.

  14. Properties of electromagnetic fields generated by tsunami first arrivals: Classification based on the ocean depth

    NASA Astrophysics Data System (ADS)

    Minami, Takuto; Toh, Hiroaki; Tyler, Robert H.

    2015-04-01

    Tsunami flow coupled with the geomagnetic field generates electric currents and associated magnetic fields. Although electromagnetic (EM) tsunami signals can be used for analysis and even forecasting tsunami propagation, the dynamically self-consistent effect of shoaling water depth on the fluid + electrodynamics has not been adequately clarified. In this study, we classify tsunami EM phenomena into three cases based on the ocean depth and find that the deeper ocean results in stronger self-induction due to the increase in both tsunami phase velocity and ocean conductance. In this deep-ocean case, the phase lead of the vertical magnetic variation relative to the sea surface elevation is smaller, while an initial rise in the horizontal magnetic component becomes observable prior to tsunami arrival. Furthermore, we confirm that the enhancement of tsunami height in shallower oceans shifts the ocean depth supplying maximum amplitudes of tsunami magnetic fields from approximately 2.0 km to 1.5 km.

  15. Variability of the oceanic environment and basal melting of the Dotson Ice Shelf, West Antarctica, 2000 to 2014

    NASA Astrophysics Data System (ADS)

    Shoosmith, Deb; Jenkins, Adrian; Dutrieux, Pierre; Jacobs, Stan; Kim, Tae Wan; Lee, Sang Hoon; Ha, Ho Kyung; Stammerjohn, Sharon

    2016-04-01

    It is well known that the ocean plays a key role in the process of mass loss from ice sheets through iceberg calving and basal melting. The Amundsen Sea, in the eastern Pacific sector of the Southern Ocean, is a region where the ice shelves are rapidly thinning. The widespread, coherent nature of the thinning suggests oceanic forcing, which has now been well documented for Pine Island Glacier. Studies using satellite data have indicated that Dotson Ice Shelf was melting at a rate of 8 m per year and thinning by about 3 m per year during the 2003 - 2008 period. This study takes a slightly longer term perspective, exploiting oceanographic observations spanning a decade and a half (2000 - 2014) that have been obtained at the Dotson Ice Front. A total of 7 hydrographic sections reveal variability in the oceanographic environment in front of the ice shelf and associated changes in meltwater production over time. We quantify the variability in circulation and net meltwater transport from beneath the ice shelf to produce estimates of the basal melt rate for this 15 year period. We find that changes in ocean heat content in front of the ice shelf drive high variability in melting on multi-annual to decadal time-scales.

  16. A VR-Ocean system for interactive geospatial analysis and 4D visualization of the marine environment around Antarctica

    NASA Astrophysics Data System (ADS)

    Li, Wenqing; Chen, Ge; Kong, Qianqian; Wang, Zhenzhen; Qian, Chengcheng

    2011-11-01

    The development of the VR-Ocean system coincides with the first availability of more than 15 years (1992-2009) of the merged altimeter data from up to four concurrent satellite missions (Topex/Poseidon, ERS-1 and 2, ENVISAT, Jason-1, and Geosat Follow-On) and ETOPO1 Ice Surface data (1 arc-minute global relief model of the Earth's surface that integrates land topography and ocean bathymetry). In the polar-region-oriented VR-Ocean system, the seabed and continental topography data south of 45°S were organized in a circular area and rendered in the form of geometry clipmaps. Maps of Sea-Level Anomalies (MSLA) data for the same district were extracted and streamlined in time order. A memory-mapped file was used to accelerate file loading speed, and sea surfaces of different times were rendered in turn as a vertex buffer object (VBO) and accelerated by the graphic processing unit (GPU). As a result, roaming anywhere at any angle of view and geospatial analysis are interactively obtained and dynamically presented in real-time using the 4D VR-Ocean system. As an attempt, we did a case study on ice melting and sea-level rise around the Antarctic. This system is expected to make a significant contribution to the description, understanding, prediction, and demonstration of 4D information and properties on both regional and hemispheric scales in a virtual environment.

  17. Distribution and controls on gas hydrate in the ocean-floor environment

    SciTech Connect

    Dillon, W.P.

    1995-12-31

    Methane hydrate, a crystalline solid that is formed of water and gas molecules, is widespread in oceanic sediments. It occurs at water depths that exceed 300 to 500 m and in a zone that commonly extends from the sea floor, down several hundred meters - the base of the zone is limited by increased temperature. To determine factors that control gas hydrate concentration, we have mapped its distribution off the U.S. Atlantic coast using acoustic remote-sensing methods. Most natural gas hydrate is formed from biogenic methane, and therefore it is concentrated where there is a rapid accumulation of organic detritus and also where there is a rapid accumulation of sediments (which protect detritus from oxidation). When hydrate fills the pore space of sediment, it can reduce permeability and create a gas trap. Such trapping of gas beneath hydrate may cause the formation of the most concentrated hydrate deposits, perhaps because the gas that is held in the trap can slowly diffuse upwards or migrate through faults. Hydrate-sealed traps are formed by hills on the sea floor, by dipping strata, or by salt(?) domes. Off the southeastern United States, a small area (only 3000 km{sup 2}) beneath a ridge formed by rapidly-deposited sediments appears to contain a volume of methane in hydrate that is equivalent to {approximately}30 times the U.S. annual consumption of gas. The breakdown of hydrate can cause submarine landslides by converting the hydrate to gas plus water and generating a rise of pore pressure. Conversely, sea-floor landslides can cause breakdown of hydrate by reducing the pressure in sediments. These interacting processes may cause cascading slides, which would result in breakdown of hydrate and release of methane to the atmosphere. This addition of methane to the global greenhouse would significantly influence climate. Gas hydrate in sea-floor sediments is potentially significant to climate, energy resources, and sea-floor stability.

  18. Olivine friction at the base of oceanic seismogenic zones

    USGS Publications Warehouse

    Boettcher, M.S.; Hirth, G.; Evans, B. M.

    2007-01-01

    We investigate the strength and frictional behavior of olivine aggregates at temperatures and effective confining pressures similar to those at the base of the seismogenic zone on a typical ridge transform fault. Triaxial compression tests were conducted on dry olivine powder (grain size ???60 ??m) at effective confining pressures between 50 and 300 MPa (using Argon as a pore fluid), temperatures between 600??C and 1000??C, and axial displacement rates from 0.06 to 60 ??m/s (axial strain rates from 3 ?? 10-6 to 3 ?? 10-3 s-1). Yielding shows a negative pressure dependence, consistent with predictions for shear enhanced compaction and with the observation that samples exhibit compaction during the initial stages of the experiments. A combination of mechanical data and microstructural observations demonstrate that deformation was accommodated by frictional processes. Sample strengths were pressure-dependent and nearly independent of temperature. Localized shear zones formed in initially homogeneous aggregates early in the experiments. The frictional response to changes in loading rate is well described by rate and state constitutive laws, with a transition from velocity-weakening to velocity-strengthening at 1000??C. Microstructural observations and physical models indicate that plastic yielding of asperities at high temperatures and low axial strain rates stabilizes frictional sliding. Extrapolation of our experimental data to geologic strain rates indicates that a transition from velocity weakening to velocity strengthening occurs at approximately 600??C, consistent with the focal depths of earthquakes in the oceanic lithosphere. Copyright 2007 by the American Geophysical Union.

  19. A CORBA-based manufacturing environment

    SciTech Connect

    Pancerella, C.M.; Whiteside, R.A.; Klevgard, P.A.

    1996-08-01

    A CORBA-based distributed object software system was developed for Sandia`s Agile Manufacturing Testbed (SAMT). This information architecture supports the goals of agile manufacturing: rapid response to changing requirements; small lot machining; reduction in both time and cost of the product realization process; and integration within a heterogeneous, wide-area networked enterprise. Features of the resulting software-controlled manufacturing environment are: (1) Easy plug-and-play of manufacturing devices. (2) Support for both automated and manual operations. (3) Information flow both into and out of manufacturing devices. (4) Dynamic task sequencer. Each of the heterogeneous physical objects (lathe, milling machine, robot arm, etc.) has a corresponding software object that supports a common IDL interface called IDevice. This interface provides operations for material processing, material movement, status monitoring, and other administrative tasks. CORBA objects allow for the encapsulation of a machine tool, its controller, and the network interface to the controller. Both manual and automated operations are supported by the software system. If an IDevice object receives a request for a non-automated operation, it uses an associated Console object to affect the operation by communications with a human machinist. A design goal of the Console object for a machine is to provide an information-intensive environment for the machinist, rather than just the transmittal of instructions to be carried out. In addition to the flow of information into manufacturing devices (e.g., control and NC code), the software architecture supports the easy extraction of data (e.g., sensor data or inspection reports) back out of the machine and into the broader information processing environment The task sequencer object dynamically locates devices, accepts jobs, and dispatches tasks in the manufacturing cell. A job script captures setup operations, material movement, and processing.

  20. The Ocean as a Unique Therapeutic Environment: Developing a Surfing Program

    ERIC Educational Resources Information Center

    Clapham, Emily D.; Armitano, Cortney N.; Lamont, Linda S.; Audette, Jennifer G.

    2014-01-01

    Educational aquatic programming offers necessary physical activity opportunities to children with disabilities and the benefits of aquatic activities are more pronounced for children with disabilities than for their able-bodied peers. Similar benefits could potentially be derived from surfing in the ocean. This article describes an adapted surfing…

  1. Preliminary testing of turbulence and radionuclide transport modeling in deep ocean environment

    SciTech Connect

    Onishi, Y.; Dummuller, D.C.; Trent, D.S.; Washington State Univ., Pullman, WA; Pacific Northwest Lab., Richland, WA )

    1989-03-01

    Pacific Northwest Laboratory (PNL) performed a study for the US Environmental Protection Agency's Office of Radiation Programs to (1) identify candidate models for regional modeling of low-level waste ocean disposal sites in the mid-Atlantic ocean; (2) evaluate mathematical representation of the model's eddy viscosity/dispersion coefficients; and (3) evaluate the adequacy of the k-{epsilon} turbulence model and the feasibility of one of the candidate models, TEMPEST{copyright}/FLESCOT{copyright}, to deep-ocean applications on a preliminary basis. PNL identified the TEMPEST{copyright}/FLESCOT{copyright}, FLOWER, Blumberg's, and RMA 10 models as appropriate candidates for the regional radionuclide modeling. Among these models, TEMPEST/FLESCOT is currently the only model that solves distributions of flow, turbulence (with the k-{epsilon} model), salinity, water temperature, sediment, dissolved contaminants, and sediment-sorbed contaminants. Solving the Navier-Stokes equations using higher order correlations is not practical for regional modeling because of the prohibitive computational requirements; therefore, the turbulence modeling is a more practical approach. PNL applied the three-dimensional code, TEMPEST{copyright}/FLESCOT{copyright} with the k-{epsilon} model, to a very simple, hypothetical, two-dimensional, deep-ocean case, producing at least qualitatively appropriate results. However, more detailed testing should be performed for the further testing of the code. 46 refs., 39 figs., 6 tabs.

  2. Lunar base activities and the lunar environment

    NASA Technical Reports Server (NTRS)

    Vondrak, Richard R.

    1992-01-01

    The Moon is an attractive site for astronomical observatories and other facilities because of the absence of a substantial lunar atmosphere and the stability of the lunar surface. The present lunar atmosphere is sufficiently transparent that there is no significant image distortion due to absorption or refraction. This thin atmosphere results from a combination of small sources and prompt losses. The major source that has been identified is the solar wind, whose total mass input into the lunar atmosphere is approximately 50 gm/sec. The major components of the solar wind are light elements (H and He) that promptly escape from the lunar surface by exospheric evaporation (Jeans' escape). The principal atmospheric loss mechanism for heavier gases is photoionization within a period of weeks to months, followed by immediate loss to the solar wind. Lunar base activities will modify the lunar atmosphere if gas is released at a larger rate than that now occurring naturally. Possible gas sources are rocket exhaust, processing of lunar materials, venting of pressurized volumes, and astronaut life support systems. For even modest lunar base activity, such sources will substantially exceed natural sources, although effects are expected to be localized and transient. The Apollo database serves as a useful reference for both measurements of the natural lunar environment and its modification by lunar base activities.

  3. Vision-based localization in urban environments

    NASA Astrophysics Data System (ADS)

    McHenry, Michael; Cheng, Yang; Matthies, Larry

    2005-05-01

    As part of DARPA's MARS2020 program, the Jet Propulsion Laboratory has developed a vision-based system for localization in urban environments that requires neither GPS nor active sensors. System hardware consists of a pair of small FireWire cameras and a standard Pentium-based computer. The inputs to the software system consist of: 1) a crude grid-based map describing the positions of buildings, 2) an initial estimate of robot location and 3) the video streams produced by the stereo pair. At each step during the traverse the system: captures new image data, finds image features hypothesized to lie on the outside of a building, computes the range to those features, determines an estimate of the robot's motion since the previous step and combines that data with the map to update a probabilistic representation of the robot's location. This probabilistic representation allows the system to simultaneously represent multiple possible locations. For our testing, we have derived the a priori map manually using non-orthorectified overhead imagery, although this process could be automated. The software system consists of three primary components. The first is a stereo-based visual odometry system that calculates the 6-degree of freedom camera motion between sequential frames. The second component uses a set of heuristics to identify straight-line segments that are likely to be part of a building exterior. Ranging to these straight-line features is computed using binocular or wide-baseline stereo. The resulting features and the associated range measurements are fed to the third software component, a particle-filter based localization system. This system uses the map and the most recent results from the first two to update the estimate of the robot's location. This report summarizes the design of both the hardware and software and describes the results of applying the system to the global localization of a camera system over an approximately half-kilometer traverse across JPL

  4. Atmosphere-ocean gas exchange based on radiocarbon data

    NASA Astrophysics Data System (ADS)

    Byalko, Alexey

    2014-05-01

    In recent decades, the intensity of global atmospheric convection has accelerated faster than climate warming; it is possible to judge this process from indirect data. Increasing ocean salinity contrasts provide evidence that evaporation has intensified [1]; sea surface wind velocities and wave heights have increased [2]. The CO2 gas exchange between the atmosphere and ocean must also simultaneously increase. Monthly measurements of atmospheric CO2 concentration have been published since 1958 [3], but directly measuring its fluxes from the atmosphere to the ocean and back is hardly possible. We show they can be reconstructed from 14C isotope concentration data. In the past century, two processes influenced the atmospheric 14C concentration in opposite directions: burning fossil fuels and testing nuclear weapons in the atmosphere. We compare the gas exchange theory with measurements of radiocarbon content in the atmosphere [4—6], which allows assessing the gas exchange quantitatively for the ocean to atmosphere and atmosphere to ocean fluxes separately for period 1960—2010 [7]. References 1. Durack P. J. and Wijffels S. E., J. Climate 23, 4342 (2010). 2. Young I. R., Sieger S., and Babanin A.V., Science 332, 451 (2011). 3. NOAA Earth System Research Laboratory Data: ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt. 4. Nydal R., Lövseth K. // J. Geophys. Res. 1983. V. 88. P. 3579. 5. Levin I., Kromer B. // Radiocarbon. 1997. V. 39. P. 205. 6. Miller J.B., Lehman S.J., Montzka S.A., et al. // J. Geophys. Res. 2012. V. 117. D08302. 7. Byalko A.V. Doklady Physics, 2013. V. 58, 267-271.

  5. 33 CFR 334.866 - Pacific Ocean at Naval Base Coronado, in the City of Coronado, San Diego County, California...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Pacific Ocean at Naval Base... AND RESTRICTED AREA REGULATIONS § 334.866 Pacific Ocean at Naval Base Coronado, in the City of... westerly into the waters of the Pacific Ocean from a point on the beach of Naval Base Coronado,...

  6. 33 CFR 334.866 - Pacific Ocean at Naval Base Coronado, in the City of Coronado, San Diego County, California...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Pacific Ocean at Naval Base... AND RESTRICTED AREA REGULATIONS § 334.866 Pacific Ocean at Naval Base Coronado, in the City of... westerly into the waters of the Pacific Ocean from a point on the beach of Naval Base Coronado,...

  7. 33 CFR 334.866 - Pacific Ocean at Naval Base Coronado, in the City of Coronado, San Diego County, California...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Pacific Ocean at Naval Base... AND RESTRICTED AREA REGULATIONS § 334.866 Pacific Ocean at Naval Base Coronado, in the City of... westerly into the waters of the Pacific Ocean from a point on the beach of Naval Base Coronado,...

  8. 33 CFR 334.866 - Pacific Ocean at Naval Base Coronado, in the City of Coronado, San Diego County, California...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Pacific Ocean at Naval Base... AND RESTRICTED AREA REGULATIONS § 334.866 Pacific Ocean at Naval Base Coronado, in the City of... westerly into the waters of the Pacific Ocean from a point on the beach of Naval Base Coronado,...

  9. 33 CFR 334.866 - Pacific Ocean at Naval Base Coronado, in the City of Coronado, San Diego County, California...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Pacific Ocean at Naval Base... AND RESTRICTED AREA REGULATIONS § 334.866 Pacific Ocean at Naval Base Coronado, in the City of... westerly into the waters of the Pacific Ocean from a point on the beach of Naval Base Coronado,...

  10. Deposition of organic carbon-rich sediments in narrow marine basins and open-marine upwelling environments - New results from the ocean drilling program

    SciTech Connect

    Stein, R. )

    1988-08-01

    Detailed sedimentological and organic geochemical investigations have been performed on Neogene sediments from ODP site 645 (Baffin Bay), ODP site 658 (upwelling area of northwest Africa), and ODP site 679 (upwelling area off Peru). The study is mainly based on (1) data derived from total organic carbon and nitrogen analyses, Rock-Eval pyrolysis, and kerogen microscopy (2) sedimentation rates, and (3) x-ray diffraction analyses. The main objective of this study was to point out the most important factors controlling the accumulation of organic carbon in the different sedimentary environments, such as supply of terrigenous organic matter, productivity of marine organic matter, and preservation of organic matter. These new results from the investigation of ODP sediments are compared with DSDP data from the Mesozoic Atlantic Ocean to characterize the depositional environments of Mesozoic black shales.

  11. Export Fluxes in Contrasting Environments of the South-East Pacific Ocean Derived From Drifting Sediment traps (BIOSOPE)

    NASA Astrophysics Data System (ADS)

    Miquel, J.; Gasser, B.; Claustre, H.

    2006-12-01

    The South-East Pacific presents contrasting oceanographic environments related to different oceanographic features such as High Nutrient Low Chlorophyl (HNLC) zones, upwelling of eastern boundaries or ultra- oligotrophy of the central gyre. This results in significant differences in particle production in surface waters and export to the deeper ocean. During the BIOSOPE (BIogeochemistry and Optics SOuth Pacific Experiment) cruise held in October-December 2004, particle flux in upper waters was assessed using drifting sediment traps. Traps were deployed at 2 depths (below the maximum chl.a and at the base of the euphotic layer) in six geographical areas, ranging from the oligotrophic central gyre through the mesotrophic area off Marquesas Islands to the eutrophic waters off the South-American coast. For all analyzed parameters fluxes were contrastingly different at the various sites, with lowest fluxes at the central gyre area and highest fluxes at the upwelling sites. Mass flux ranged from 2-7 mg m-2 d-1 to 410-630 mg m-2 d-1, POC flux from less than 1 mg POC m-2 d-1 up to 63 mg POC m^{- 2} d-1, and Th-234 from 35-47 dpm m-2 d-1 to >5000 dpm m-2 d-1. Fluxes were always lower at the deeper horizon except for Th-234 flux which was variable. Also, fluxes were very different at the two upwelling sites studied. The relation between the environmental and trophic characteristics of the sites visited and the two orders of magnitude in fluxes observed is discussed.

  12. Vision Based Localization in Urban Environments

    NASA Technical Reports Server (NTRS)

    McHenry, Michael; Cheng, Yang; Matthies, Larry

    2005-01-01

    As part of DARPA's MARS2020 program, the Jet Propulsion Laboratory developed a vision-based system for localization in urban environments that requires neither GPS nor active sensors. System hardware consists of a pair of small FireWire cameras and a standard Pentium-based computer. The inputs to the software system consist of: 1) a crude grid-based map describing the positions of buildings, 2) an initial estimate of robot location and 3) the video streams produced by each camera. At each step during the traverse the system: captures new image data, finds image features hypothesized to lie on the outside of a building, computes the range to those features, determines an estimate of the robot's motion since the previous step and combines that data with the map to update a probabilistic representation of the robot's location. This probabilistic representation allows the system to simultaneously represent multiple possible locations, For our testing, we have derived the a priori map manually using non-orthorectified overhead imagery, although this process could be automated. The software system consists of two primary components. The first is the vision system which uses binocular stereo ranging together with a set of heuristics to identify features likely to be part of building exteriors and to compute an estimate of the robot's motion since the previous step. The resulting visual features and the associated range measurements are software component, a particle-filter based localization system. This system uses the map and the then fed to the second primary most recent results from the vision system to update the estimate of the robot's location. This report summarizes the design of both the hardware and software and will include the results of applying the system to the global localization of a robot over an approximately half-kilometer traverse across JPL'S Pasadena campus.

  13. Integrating Place-based and Cultural Knowledge Systems into a Communicating Ocean Sciences course in Hawaii

    NASA Astrophysics Data System (ADS)

    Lemus, J.; Coopersmith, A.; Duncan Seraphin, K.

    2011-12-01

    The Pacific Ocean Literacy for Youth, Publics, Professionals and Scientists (POLYPPS) collaborative program between the University of Hawaii and the Center for Ocean Sciences Education Excellence - California (COSEE CA) at UC Berkeley operates on the premise that ocean literacy is most effectively achieved through scientists and educators working together within a place-based context. We have partnered with a dynamic and respected group of traditional practitioners and a graduate student trained in Hawaiian Studies to advise efforts for respectfully and responsibly integrating aspects of traditional ecological knowledge with the existing course material. The goal is to build a collaborative network that connects ocean research and teaching with traditional knowledge to facilitate active engagement in stewardship and policy by all ocean users. This presentation will include details of ways in which we have adapted the COSEE-CA courses in Communicating Ocean Sciences (COS) and Communicating Ocean Sciences for Informal Audiences (COSIA) for our island setting; approaches for contextualizing course elements that utilize local and traditional exemplars and knowledge systems; and example outreach projects produced by students in our Communicating Ocean Sciences courses.

  14. 77 FR 19030 - Automated Commercial Environment Required for the Transmission of Advance Ocean and Rail Cargo...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-29

    ... SECURITY U.S. Customs and Border Protection Automated Commercial Environment Required for the Transmission... recently completed the testing of the Automated Commercial Environment (ACE) for the transmission of..., rail or truck. See Required Advance Electronic ] Presentation of Cargo Information, 68 FR...

  15. The Polar Oceans and Their Role in Shaping the Global Environment

    NASA Astrophysics Data System (ADS)

    Johannessen, O. M.; Muench, R. D.; Overland, J. E.

    On June 24, 1993, one hundred years had passed since Fridtjof Nansen and his companions set out on one of the most daring and exciting research expeditions the world had ever seen. They allowed their vessel, the Fram, to be frozen into the ice close to the New Siberian Islands, in the Arctic Ocean. Three years were to elapse before the ice released its hold on the Fram and allowed her to return to Norway via the strait between Greenland and Spitsbergen, which later came to be known as Fram Strait. The research carried out during Fram's drift in the ice altered forever our concept of the Arctic Basin.

  16. A novel spatio-temporal scale based on ocean currents unravels environmental drivers of reproductive timing in a marine predator.

    PubMed

    Afán, Isabel; Chiaradia, André; Forero, Manuela G; Dann, Peter; Ramírez, Francisco

    2015-07-01

    Life-history strategies have evolved in response to predictable patterns of environmental features. In practice, linking life-history strategies and changes in environmental conditions requires comparable space-time scales between both processes, a difficult match in most marine system studies. We propose a novel spatio-temporal and dynamic scale to explore marine productivity patterns probably driving reproductive timing in the inshore little penguin (Eudyptula minor), based on monthly data on ocean circulation in the Southern Ocean, Australia. In contrast to what occurred when considering any other fixed scales, little penguin's highly variable laying date always occurred within the annual peak of ocean productivity that emerged from our newly defined dynamic scale. Additionally, local sea surface temperature seems to have triggered the onset of reproduction, acting as an environmental cue informing on marine productivity patterns at our dynamic scale. Chlorophyll-a patterns extracted from this scale revealed that environment factors in marine ecosystems affecting breeding decisions are related to a much wider region than foraging areas that are commonly used in current studies investigating the link between animals' life history and their environment. We suggest that marine productivity patterns may be more predictable than previously thought when environmental and biological data are examined at appropriate scales. PMID:26063848

  17. A novel spatio-temporal scale based on ocean currents unravels environmental drivers of reproductive timing in a marine predator

    PubMed Central

    Afán, Isabel; Chiaradia, André; Forero, Manuela G.; Dann, Peter; Ramírez, Francisco

    2015-01-01

    Life-history strategies have evolved in response to predictable patterns of environmental features. In practice, linking life-history strategies and changes in environmental conditions requires comparable space–time scales between both processes, a difficult match in most marine system studies. We propose a novel spatio-temporal and dynamic scale to explore marine productivity patterns probably driving reproductive timing in the inshore little penguin (Eudyptula minor), based on monthly data on ocean circulation in the Southern Ocean, Australia. In contrast to what occurred when considering any other fixed scales, little penguin's highly variable laying date always occurred within the annual peak of ocean productivity that emerged from our newly defined dynamic scale. Additionally, local sea surface temperature seems to have triggered the onset of reproduction, acting as an environmental cue informing on marine productivity patterns at our dynamic scale. Chlorophyll-a patterns extracted from this scale revealed that environment factors in marine ecosystems affecting breeding decisions are related to a much wider region than foraging areas that are commonly used in current studies investigating the link between animals' life history and their environment. We suggest that marine productivity patterns may be more predictable than previously thought when environmental and biological data are examined at appropriate scales. PMID:26063848

  18. Continent-ocean chemical heterogeneity in the mantle based on seismic tomography.

    PubMed

    Forte, A M; Dziewonski, A M; O'connell, R J

    1995-04-21

    Seismic models of global-scale lateral heterogeneity in the mantle show systematic differences below continents and oceans that are too large to be purely thermal in origin. An inversion of the geoid, based on a seismic model that includes viscous flow in the mantle, indicates that the differences beneath continents and oceans can be accounted for by differences in composition in the upper mantle superposed on mantle-wide thermal heterogeneities. The net continent-ocean density differences, integrated over depth, are small and cause only a low flux of mass and heat across the asthenosphere and mantle transition zone. PMID:17746544

  19. Bet hedging in a warming ocean: predictability of maternal environment shapes offspring size variation in marine sticklebacks.

    PubMed

    Shama, Lisa N S

    2015-12-01

    Bet hedging at reproduction is expected to evolve when mothers are exposed to unpredictable cues for future environmental conditions, whereas transgenerational plasticity (TGP) should be favoured when cues reliably predict the environment offspring will experience. Since climate predictions forecast an increase in both temperature and climate variability, both TGP and bet hedging are likely to become important strategies to mediate climate change effects. Here, the potential to produce variably sized offspring in both warming and unpredictable environments was tested by investigating whether stickleback (Gasterosteus aculeatus) mothers adjusted mean offspring size and within-clutch variation in offspring size in response to experimental manipulation of maternal thermal environment and predictability (alternating between ambient and elevated water temperatures). Reproductive output traits of F1 females were influenced by both temperature and environmental predictability. Mothers that developed at ambient temperature (17 °C) produced larger, but fewer eggs than mothers that developed at elevated temperature (21 °C), implying selection for different-sized offspring in different environments. Mothers in unpredictable environments had smaller mean egg sizes and tended to have greater within-female egg size variability, especially at 21 °C, suggesting that mothers may have dynamically modified the variance in offspring size to spread the risk of incorrectly predicting future environmental conditions. Both TGP and diversification influenced F2 offspring body size. F2 offspring reared at 21 °C had larger mean body sizes if their mother developed at 21 °C, but this TGP benefit was not present for offspring of 17 °C mothers reared at 17 °C, indicating that maternal TGP will be highly relevant for ocean warming scenarios in this system. Offspring of variable environment mothers were smaller but more variable in size than offspring from constant environment

  20. Piezometer-probe technology for geotechnical investigations in coastal and deep-ocean environments

    SciTech Connect

    Bennett, R.H.; Burns, J.T.; Lipkin, J.; Percival, C.M.

    1983-01-01

    Three multisensor piezometer probes were developed and field tested for use in coastal (shallow water) fine-grained Marine soils. Offshore sites were investigated in the Mississippi Delta. Pore water pressure measurements were determined at several depths below the sea floor using both absolute and differential pressure sensors placed in a four inch diameter probe. Pressure sensors were hard-wired to nearby platforms where signals were conditioned and analog recording devices monitored pore water pressure changes in the marine soils. Pore water pressures were monitored for several months. Two single sensor piezometer probes, eight millimeters in diameter, were developed for deep-ocean investigations. These probes use differential pressure sensors and were tested in a hyperbaric chamber pressurized to 55 MPa (8000 psi). Testing was performed for a period of five weeks under high hydrostatic pressure with the probes inserted in reconstituted illitic marine soil. Small differential pore water pressures responded to both mechanically and thermally generated forcing functions. During shallow water investigations and simulated deep-ocean pressure tests, the sensors exhibited excellent sensitivity and stability. These developments in piezometer probe technology provide a means of assessing important geotechnical parameters of fine-grained seabed deposits.

  1. Model-based localization for a shallow ocean experiment

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1995-07-19

    In this paper a modern approach was developed to solve the passive localization problem in ocean acoustics using the state-space formulation. It is shown that the inherent structure of the resulting processor consists of a parameter estimator coupled to a nonlinear optimization scheme. The parameter estimator is design using an acoustic propagation model in developing the modern identifier required for localization. The detection and localization of an acoustic source has long been the motivation of early sonar systems. With the advent of quieter and quieter submarines due to new manufacturing technologies and the next proliferation of diesel powered vessels, the need for more sophisticated processing techniques has been apparent for quite some time.

  2. New ERP predictions based on (sub-)daily ocean tides from satellite altimetry data

    NASA Astrophysics Data System (ADS)

    Madzak, Matthias; Böhm, Sigrid; Böhm, Johannes; Bosch, Wolfgang; Schuh, Harald

    2013-04-01

    A new model for Earth rotation variations based on ocean tide models is highly desirable in order to close the gap between geophysical Earth rotation models and geodetic observations. We have started a project, SPOT (Short Period Ocean Tidal variations in Earth Rotation), with the goal to develop a new model of short period Earth rotation variations based on one of the best currently available empirical ocean tide models obtained from satellite altimetry. We employ the EOT11a model which is an upgrade of EOT08a, developed at DGFI, Munich. As EOT11a does not provide the tidal current velocities which are fundamental contributors to Earth rotation excitation, the calculation of current velocities from the tidal elevations is one of three main areas of research in project SPOT. The second key aspect is the conversion from ocean tidal angular momentum to the corresponding ERP variations using state-of-the-art transfer functions. A peculiar innovation at this step will be to consider the Earth's response to ocean tidal loading based on a realistic Earth model, including an anelastic mantle. The third part of the project deals with the introduction of the effect of minor tides. Ocean tide models usually only provide major semi-diurnal and diurnal tidal terms and the minor tides have to be inferred through admittance assumptions. Within the proposed project, selected minor tidal terms and the corresponding ERP variations shall be derived directly from satellite altimetry data. We determine ocean tidal angular momentum of four diurnal and five sub-daily tides from EOT11a and apply the angular momentum approach to derive a new model of ocean tidal Earth rotation variations. This poster gives a detailed description of project SPOT as well as the status of work progress. First results are presented as well.

  3. Plasmonics Based Harsh Environment Compatible Chemical Sensors

    SciTech Connect

    Michael Carpenter

    2012-01-15

    Au-YSZ, Au-TiO{sub 2} and Au-CeO{sub 2} nanocomposite films have been investigated as a potential sensing element for high-temperature plasmonic sensing of H{sub 2}, CO, and NO{sub 2} in an oxygen containing environment. The Au-YSZ and Au-TiO{sub 2} films were deposited using PVD methods, while the CeO{sub 2} thin film was deposited by molecular beam epitaxy (MBE) and Au was implanted into the as-grown film at an elevated temperature followed by high temperature annealing to form well-defined Au nanoclusters. Each of the films were characterized by x-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). For the gas sensing experiments, separate exposures to varying concentrations of H{sub 2}, CO, and NO{sub 2} were performed at a temperature of 500°C in oxygen backgrounds of 5.0, 10, and ~21% O{sub 2}. Changes in the localized surface plasmon resonance (LSPR) absorption peak were monitored during gas exposures and are believed to be the result of oxidation-reduction processes that fill or create oxygen vacancies in the respective metal oxides. This process affects the LSPR peak position either by charge exchange with the Au nanoparticles or by changes in the dielectric constant surrounding the particles. Hyperspectral multivariate analysis was used to gauge the inherent selectivity of the film between the separate analytes. From principal component analysis (PCA), unique and identifiable responses were seen for each of the analytes. Linear discriminant analysis (LDA) was also used on the Au-CeO{sub 2} results and showed separation between analytes as well as trends in gas concentration. Results indicate that each of the films are is selective towards O{sub 2}, H{sub 2}, CO, and NO{sub 2} in separate exposures. However, when the films were analyzed in a sensor array based experiment, ie simultaneous exposures to the target gases, PCA analysis of the combined response showed an even greater selective character towards the target gases. Combined

  4. Spatial Distribution and Temporal Patterns of Cassin's Auklet Foraging and Their Euphausiid Prey in a Variable Ocean Environment.

    PubMed

    Manugian, Suzanne; Elliott, Meredith L; Bradley, Russ; Howar, Julie; Karnovsky, Nina; Saenz, Benjamin; Studwell, Anna; Warzybok, Pete; Nur, Nadav; Jahncke, Jaime

    2015-01-01

    Krill (Euphausiids) play a vital ecosystem role in many of the world's most productive marine regions, providing an important trophic linkage. We introduce a robust modeling approach to link Cassin's auklet (Ptychoramphus aleuticus) abundance and distribution to large-scale and local oceanic and atmospheric conditions and relate these patterns to similarly modeled distributions of an important prey resource, krill. We carried out at-sea strip transect bird surveys and hydroacoustic assessments of euphausiids (2004-2013). Data informed separate, spatially-explicit predictive models of Cassin's auklet abundance (zero-inflated negative binomial regression) and krill biomass (two-part model) based on these surveys. We established the type of prey responsible for acoustic backscatter by conducting net tows of the upper 50 m during surveys. We determined the types of prey fed to Cassin's auklet chicks by collecting diet samples from provisioning adults. Using time-depth-recorders, we found Cassin's auklets utilized consistent areas in the upper water column, less than 30 m, where krill could be found (99.5% of dives were less than 30 m). Birds primarily preyed upon two species of euphausiids, Euphausia pacifica and Thysanoessa spinifera, which were available in the upper water column. Cassin's auklet abundance was best predicted by both large scale and localized oceanic processes (upwelling) while krill biomass was best predicted by local factors (temperature, salinity, and fluorescence) and both large scale and localized oceanic processes (upwelling). Models predicted varying krill and bird distribution by month and year. Our work informs the use of Cassin's auklet as a valuable indicator or krill abundance and distribution and strengthens our understanding of the link between Cassin's auklet and its primary prey. We expect future increases in frequency and magnitude of anomalous ocean conditions will result in decreased availability of krill leading to declines in the

  5. Spatial Distribution and Temporal Patterns of Cassin’s Auklet Foraging and Their Euphausiid Prey in a Variable Ocean Environment

    PubMed Central

    Manugian, Suzanne; Elliott, Meredith L.; Bradley, Russ; Howar, Julie; Karnovsky, Nina; Saenz, Benjamin; Studwell, Anna; Warzybok, Pete; Nur, Nadav; Jahncke, Jaime

    2015-01-01

    Krill (Euphausiids) play a vital ecosystem role in many of the world’s most productive marine regions, providing an important trophic linkage. We introduce a robust modeling approach to link Cassin’s auklet (Ptychoramphus aleuticus) abundance and distribution to large-scale and local oceanic and atmospheric conditions and relate these patterns to similarly modeled distributions of an important prey resource, krill. We carried out at-sea strip transect bird surveys and hydroacoustic assessments of euphausiids (2004–2013). Data informed separate, spatially-explicit predictive models of Cassin’s auklet abundance (zero-inflated negative binomial regression) and krill biomass (two-part model) based on these surveys. We established the type of prey responsible for acoustic backscatter by conducting net tows of the upper 50 m during surveys. We determined the types of prey fed to Cassin’s auklet chicks by collecting diet samples from provisioning adults. Using time-depth-recorders, we found Cassin’s auklets utilized consistent areas in the upper water column, less than 30 m, where krill could be found (99.5% of dives were less than 30 m). Birds primarily preyed upon two species of euphausiids, Euphausia pacifica and Thysanoessa spinifera, which were available in the upper water column. Cassin’s auklet abundance was best predicted by both large scale and localized oceanic processes (upwelling) while krill biomass was best predicted by local factors (temperature, salinity, and fluorescence) and both large scale and localized oceanic processes (upwelling). Models predicted varying krill and bird distribution by month and year. Our work informs the use of Cassin’s auklet as a valuable indicator or krill abundance and distribution and strengthens our understanding of the link between Cassin’s auklet and its primary prey. We expect future increases in frequency and magnitude of anomalous ocean conditions will result in decreased availability of krill leading

  6. Noninvasive probing of the ocean surface using laser-based nonlinear optical methods

    SciTech Connect

    Korenowski, G.M.; Frysinger, G.S.; Asher, W.E. . Dept. of Chemistry)

    1992-06-01

    The laser-based nonlinear optical methods of second-harmonic generation and sum-frequency generation have been developed to study the chemical composition and concentration of natural surfactant materials present as slicks on the ocean surface. These noninvasive second-harmonic and sum-frequency generation methods produce signals which originate from only the top few molecular layers of the ocean surface, thereby producing an accurate picture of the ocean surface condition without interference from the bulk ocean chemistry. Chemical specificity of the methods is achieved by tuning the incident laser frequency to coincide with optical absorptions in the surface absorbed materials. We show that laser-based second-order nonlinear optical processes of SHG and SFG provide highly surface selective, noninvasive, in situ probes of the ocean surface. Although only preliminary experiments are reported in this paper, the probes provide important information about the nature of surfactants at the ocean surface and their behavior in response to dynamic forces at the sea/air interface. The future of the probes lies in their further development and use as in situ interfacial spectroscopic techniques.

  7. Ocean Science in a K-12 setting: Promoting Inquiry Based Science though Graduate Student and Teacher Collaboration

    NASA Astrophysics Data System (ADS)

    Lodico, J. M.; Greely, T.; Lodge, A.; Pyrtle, A.; Ivey, S.; Madeiros, A.; Saleem, S.

    2005-12-01

    The University of South Florida, College of Marine Science Oceans: GK-12 Teaching Fellowship Program is successfully enriching science learning via the oceans. Funded by the National Science Foundation, the program provides a unique opportunity among scientists and K-12 teachers to interact with the intention of bringing ocean science concepts and research to the classroom environment enhance the experience of learning and doing science, and to promote `citizen scientists' for the 21st century. The success of the program relies heavily on the extensive summer training program where graduate students develop teaching skills, create inquiry based science activities for a summer Oceanography Camp for Girls program and build a relationship with their mentor teacher. For the last year and a half, two graduate students from the College of Marine Science have worked in cooperation with teachers from the Pinellas county School District, Southside Fundamental Middle School. Successful lesson plans brought into a 6th grade Earth Science classroom include Weather and climate: Global warming, The Geologic timescale: It's all about time, Density: Layering liquids, and Erosion processes: What moves water and sediment. The school and students have benefited greatly from the program experiencing hands-on inquiry based science and the establishment of an after school science club providing opportunities for students to work on their science fair projects and pursuit other science interests. Students are provided scoring rubrics and their progress is creatively assessed through KWL worksheets, concept maps, surveys, oral one on one and classroom discussions and writing samples. The year culminated with a series of hands on lessons at the nearby beach, where students demonstrated their mastery of skills through practical application. Benefits to the graduate student include improved communication of current science research to a diverse audience, a better understanding of the

  8. Petrogenesis of dacite in an oceanic subduction environment: Raoul Island, Kermadec arc

    NASA Astrophysics Data System (ADS)

    Smith, Ian E. M.; Worthington, Timothy J.; Price, Richard C.; Stewart, Robert B.; Maas, R.

    2006-09-01

    Raoul Volcano in the northern Kermadec arc is typical of volcanoes in oceanic subduction systems in that it is composed mainly of low-K high-Al basalts and basaltic andesite. However, during the last 4 ka Raoul Volcano has produced mainly dacite magma in pyroclastic eruptions associated with caldera formation. The rocks produced in these episodes are almost aphyric containing only sparse crystals of plagioclase, clinopyroxene, orthopyroxene and magnetite. These apparent phenocrysts have chemical compositions that suggest that they did not crystallise from melts with the chemical composition of their host rocks. Rather they are xenocrysts and only their rims show evidence for crystallisation from their host melt. Chemical compositions of samples of the dacites show that each eruption has tapped a distinct magma batch. Compositional variations through the analysed suite cannot be accommodated in any reasonable model of fractional crystallisation from likely parental magma compositions. The hypothesis that best fits the petrology of Raoul Island dacites is one of crustal anatexis. This model requires heating of the lower crust by a magma flux to the point where dehydration melting associated with amphibole breakdown produces magma from a preconditioned source. It is suggested that Raoul is passing through an adolescent stage of development in which siliceous melts are part of an open system in which felsic and mafic magmas coexist.

  9. Bottom interacting sound at 50 km range in a deep ocean environment.

    PubMed

    Udovydchenkov, Ilya A; Stephen, Ralph A; Duda, Timothy F; Bolmer, S Thompson; Worcester, Peter F; Dzieciuch, Matthew A; Mercer, James A; Andrew, Rex K; Howe, Bruce M

    2012-10-01

    Data collected during the 2004 Long-range Ocean Acoustic Propagation Experiment provide absolute intensities and travel times of acoustic pulses at ranges varying from 50 to 3200 km. In this paper a subset of these data is analyzed, focusing on the effects of seafloor reflections at the shortest transmission range of approximately 50 km. At this range bottom-reflected (BR) and surface-reflected, bottom-reflected energy interferes with refracted arrivals. For a finite vertical receiving array spanning the sound channel axis, a high mode number energy in the BR arrivals aliases into low mode numbers because of the vertical spacing between hydrophones. Therefore, knowledge of the BR paths is necessary to fully understand even low mode number processes. Acoustic modeling using the parabolic equation method shows that inclusion of range-dependent bathymetry is necessary to get an acceptable model-data fit. The bottom is modeled as a fluid layer without rigidity, without three dimensional effects, and without scattering from wavelength-scale features. Nonetheless, a good model-data fit is obtained for sub-bottom properties estimated from the data. PMID:23039419

  10. Persistent organic pollutants carried by synthetic polymers in the ocean environment.

    PubMed

    Rios, Lorena M; Moore, Charles; Jones, Patrick R

    2007-08-01

    Thermoplastic resin pellets are melted and formed into an enormous number of inexpensive consumer goods, many of which are discarded after a relatively short period of use, dropped haphazardly onto watersheds and then make their way to the ocean where some get ingested by marine life. In 2003 and 2004 pre-production thermoplastic resin pellets and post-consumer plastic fragments were collected and analyzed for contamination for persistent organic pollutants (POPs). Samples were taken from the North Pacific Gyre, and selected sites in California, Hawaii, and from Guadalupe Island, Mexico. The total concentration of PCBs ranged from 27 to 980 ng/g; DDTs from 22 to 7100 ng/g and PAHs from 39 to 1200 ng/g, and aliphatic hydrocarbons from 1.1 to 8600 microg/g. Analytical methods were developed to extract, concentrate and identify POPs that may have accumulated on plastic fragments and plastic pellets. The results of this study confirm that plastic debris is a trap for POPs. PMID:17532349

  11. Calcareous microfossil-based orbital cyclostratigraphy in the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Marzen, Rachel E.; DeNinno, Lauren H.; Cronin, Thomas M.

    2016-10-01

    Microfaunal and geochemical proxies from marine sediment records from central Arctic Ocean (CAO) submarine ridges suggest a close relationship over the last 550 thousand years (kyr) between orbital-scale climatic oscillations, sea-ice cover, marine biological productivity and other parameters. Multiple paleoclimate proxies record glacial to interglacial cycles. To understand the climate-cryosphere-productivity relationship, we examined the cyclostratigraphy of calcareous microfossils and constructed a composite Arctic Paleoclimate Index (API) "stack" from benthic foraminiferal and ostracode density from 14 sediment cores. Following the hypothesis that API is driven mainly by changes in sea-ice related productivity, the API stack shows the Arctic experienced a series of highly productive interglacials and interstadials every ∼20 kyr. These periods signify minimal ice shelf and sea-ice cover and maximum marine productivity. Rapid transitions in productivity are seen during shifts from interglacial to glacial climate states. Discrepancies between the Arctic API curves and various global climatic, sea-level and ice-volume curves suggest abrupt growth and decay of Arctic ice shelves related to climatic and sea level oscillations.

  12. Persistence of Carbonate Platform Environments in Central Mexico during the Oceanic Anoxic Event 2: impact of the Carribean Plateau?

    NASA Astrophysics Data System (ADS)

    Bomou, Brahimsamba; Adatte, Thierry; Föllmi, Karl; Arnaud-Vanneau, Annie; Fleitmann, Dominik

    2010-05-01

    The Cenomanian-Turonian Oceanic Anoxic Event 2 is described as an interruption of normal pelagic sediment deposition by several distinct intervals of widespread oceanic anoxia (Schlanger & Jenkyns, 1976; Jenkyns, 1980; Arthur et al., 1990) characterized by black shales deposition coinciding with a positive shift in carbon isotope excursion. Some authors show a relationship between OAEs and massive volcanic events associated with the emplacement of large igneous provinces (LIPs) and sea floor spreading at mid-ocean ridges (Kuroda et al., 2007; Snow et al., 2005). High metal abundance anomalies recorded in pelagic sections (e.g. Pueblo, Colorado) coincide with the massive volcanism that built the Carribean plateau (around 93-94 Ma), associated with the onset of OAE 2 (Snow et al., 2005). Mort et al., (2007) demonstrate that the onset of the OAE 2 was triggered by a short-lived but significant increase in phosphorus burial. The bottom waters became anoxic and switched from being a P sink to a P source, sustaining the productivity in a positive feedback loop. However, the behaviour of phosphorus and trace metals at larger scale, in different paleogeography and paleodepht is still poorly known. The Axaxacualco and Baranca el Cañon sections, located at the Guerrero-Morelos carbonate platform in southern Mexico exhibit a fully correlateable d13C curves. In the distal part of the carbonate platform at Axaxacualco, the maximum d13C positive excursion coincides with oligotrophic carbonate platform environments supported by low concentrations in P and characterized by abundant and diversified benthic microfauna and rudists. The impact of OAE appears may be more significant in the proximal part of the carbonate platform at Barranca, characterized by the deposition of thick laminated microbialites indicative of mesotrophic conditions. The Morelos Carbonate platform with oligotrophic to mesotrophic conditions was persistent throughout the entire OAE2 in Central Mexico despite

  13. A Gegenbauer-based Shallow Water solver for a thick "ocean" over a rotating sphere

    NASA Astrophysics Data System (ADS)

    Shamir, Ofer; Paldor, Nathan

    2016-01-01

    Gegenbauer Harmonics which are the eigenfunctions of the Linearized Shallow Water Equations in spherical coordinates for a thick layer of ocean are examined as alternative basis functions for global-scale spectral models. The performance of this basis is compared to that of the traditional Spherical Harmonics basis by testing the accuracy and stability with which the two bases simulate a single, analytic, wave mode of the Linearized Shallow Water Equations. For the linear equations our results show that for low initial wavenumbers the Spherical Harmonics are able to conserve the single wave mode with comparable accuracy to that of the proposed Gegenbauer Harmonics basis while at high initial wavenumbers the simulation with the Spherical Harmonics is significantly less accurate than the simulation with the Gegenbauer Harmonics. By considering a range of ocean thicknesses it is found that, for thin oceans, the Spherical Harmonics become numerically unstable after about 150 days, whereas the proposed Gegenbauer Harmonics remain stable even though they too are not the eigenfunctions of the Linearized Shallow Water Equations in thin oceans. This numerical instability of the Spherical Harmonics is independent of the wave's period and was not observed in thick oceans where the simulation remained stable for at least 200 days. Our results suggest that the numerical instability of the Spherical Harmonics originates at the poles. For the non-linear equations our results show that the Spherical Harmonics solutions are less accurate than the Gegenbauer Harmonics even in a thick ocean.

  14. HOS-ocean: Open-source solver for nonlinear waves in open ocean based on High-Order Spectral method

    NASA Astrophysics Data System (ADS)

    Ducrozet, Guillaume; Bonnefoy, Félicien; Le Touzé, David; Ferrant, Pierre

    2016-06-01

    HOS-ocean is an efficient High-Order Spectral code developed to solve the deterministic propagation of nonlinear wavefields in open ocean. HOS-ocean is released as open-source, developed and distributed under the terms of GNU General Public License (GPLv3). Along with the source code, a documentation under wiki format is available which makes easy the compilation and execution of the source files. The code has been shown to be accurate and efficient.

  15. Isotopic evidence for the contemporary origin of high-molecular weight organic matter in oceanic environments

    NASA Astrophysics Data System (ADS)

    Santschi, Peter H.; Guo, Laodong; Baskaran, M.; Trumbore, Susan; Southon, John; Bianchi, Thomas S.; Honeyman, Bruce; Cifuentes, Luis

    1995-02-01

    Previous work has suggested that apparent old 14C ages for oceanic DOC are the result of mixing of different organic carbon fractions. This report provides direct evidence for a contemporary 14C age of a high-molecular-weight (HMW) fraction of colloidal organic carbon (≥10 kD). Colloidal organic matter, COM 10 (from 10 kDaltons (kD) to 0.2 μm), isolated from the upper water column of the Gulf of Mexico and the Middle Atlantic Bight (MAB) region, generally has a contemporary age (i.e., younger than a few decades), while COM 1 (from 1 kD to 0.2 μm), is apparently old: 380-4500 y BP. Thus, BMW COM 10 (3-5% of DOC) from the upper water column is derived from living particulate organic matter (POM) and cycles rapidly, while a significant fraction of low-molecular-weight (≤1 kD) DOM is likely more refractory, and cycles on much longer time scales. The presence of pigment biomarker compounds in COM 1 from the upper water column points to selected phytoplankton species as one of the sources of COM. Terrestrial carbon as another source of COM is suggested from the inverse correlation between Δ 14C and δ 13C values, as well as the increasing δ 13C values with increasing salinity. 234Th-derived turnover times of COM 10 and COM 1 from both the Gulf of Mexico and MAB are consistently short, 1-20 and 3-30 days, respectively. These short residence times support the hypothesis that 14C ages of colloidal fractions of DOC are the result of COM fractions being a mixture of several endmembers with fast and slow turnover rates.

  16. Long period grating-based ocean pH sensor in an SMS fiber

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Klimov, Denis; Kolber, Zbigniew

    2008-03-01

    A long period grating-based pH sensor has been designed in order to measure the pH in the ocean. The pH-sensitive hydrogel, which is made through the thermal crosslink of poly vinyl alcohol and poly acrylic acid, can swell or contract in response to the pH change in the surrounding environment. The sensor is designed in a single mode-multimode-single mode (SMS) fiber structure. The long period grating is written into the multimode fiber of the SMS structure using a focused CO II laser at the critical period (1 mm) of this particular multimode fiber. The hydrogel is glued underneath the SMS structure and will physically stretch or compress the long period grating hence change the phase matching condition in the SMS structure. Because of the different core sizes of the single mode fiber and the multimode fiber, only energy coupled in and out of the fundamental mode in the multimode fiber will be detected directly. The SMS structure has a higher sensitivity than using just the multimode sensing fiber. This sensor has been utilized in the seawater pH sensing in the range of 6 ~ 8. Experiments show that the sensor has a pH resolution of 0.0042.

  17. Sequential detection of a weak target in a hostile ocean environment

    SciTech Connect

    Candy, J V; Sullivan, E J

    2005-03-14

    When the underlying physical phenomenology (medium, sediment, bottom, etc.) is space-time varying along with corresponding nonstationary statistics characterizing noise and uncertainties, then sequential methods must be applied to capture the underlying processes. Sequential detection and estimation techniques offer distinct advantages over batch methods. A reasonable signal processing approach to solve this class of problem is to employ adaptive or parametrically adaptive signal models and noise to capture these phenomena. In this paper, we develop a sequential approach to solve the signal detection problem in a nonstationary environment.

  18. Workflow-Based Software Development Environment

    NASA Technical Reports Server (NTRS)

    Izygon, Michel E.

    2013-01-01

    The Software Developer's Assistant (SDA) helps software teams more efficiently and accurately conduct or execute software processes associated with NASA mission-critical software. SDA is a process enactment platform that guides software teams through project-specific standards, processes, and procedures. Software projects are decomposed into all of their required process steps or tasks, and each task is assigned to project personnel. SDA orchestrates the performance of work required to complete all process tasks in the correct sequence. The software then notifies team members when they may begin work on their assigned tasks and provides the tools, instructions, reference materials, and supportive artifacts that allow users to compliantly perform the work. A combination of technology components captures and enacts any software process use to support the software lifecycle. It creates an adaptive workflow environment that can be modified as needed. SDA achieves software process automation through a Business Process Management (BPM) approach to managing the software lifecycle for mission-critical projects. It contains five main parts: TieFlow (workflow engine), Business Rules (rules to alter process flow), Common Repository (storage for project artifacts, versions, history, schedules, etc.), SOA (interface to allow internal, GFE, or COTS tools integration), and the Web Portal Interface (collaborative web environment

  19. Understanding Social Presence in Text-Based Online Learning Environments

    ERIC Educational Resources Information Center

    Kehrwald, Benjamin

    2008-01-01

    This article reports on key aspects of a theory generative study into social presence in text-based online learning environments. The focus of the article is the nature of social presence as experienced by online learners in those environments. Employing a collective case study design, the study accessed online learners' experience-based heuristic…

  20. Observationally-Based Data/Model Metrics from the Southern Ocean Climate Model Atlas

    NASA Astrophysics Data System (ADS)

    Abell, J.; Russell, J. L.; Goodman, P. J.

    2015-12-01

    The Southern Ocean Climate Model Atlas makes available observationally-based standardized data/model metrics of the latest simulations of climate and projections of climate change from available climate models. Global climate model simulations differ greatly in the Southern Ocean, so the development of consistent, observationally-based metrics, by which to assess the fidelity of model simulations is essential. We will present metrics showing and quantifying the results of the modern day climate simulations over the Southern Ocean from models submitted as part of the CMIP5/IPCC-AR5 process. Our analysis will focus on the simulations of the temperature, salinity and carbon at various depths and along significant hydrographic sections. The models exhibit different skill levels with various metrics between models and also within individual models.

  1. A neural network-based method for merging ocean color and Argo data to extend surface bio-optical properties to depth: Retrieval of the particulate backscattering coefficient

    NASA Astrophysics Data System (ADS)

    Sauzède, R.; Claustre, H.; Uitz, J.; Jamet, C.; Dall'Olmo, G.; D'Ortenzio, F.; Gentili, B.; Poteau, A.; Schmechtig, C.

    2016-04-01

    The present study proposes a novel method that merges satellite ocean color bio-optical products with Argo temperature-salinity profiles to infer the vertical distribution of the particulate backscattering coefficient (bbp). This neural network-based method (SOCA-BBP for Satellite Ocean-Color merged with Argo data to infer the vertical distribution of the Particulate Backscattering coefficient) uses three main input components: (1) satellite-based surface estimates of bbp and chlorophyll a concentration matched up in space and time with (2) depth-resolved physical properties derived from temperature-salinity profiles measured by Argo profiling floats and (3) the day of the year of the considered satellite-Argo matchup. The neural network is trained and validated using a database including 4725 simultaneous profiles of temperature-salinity and bio-optical properties collected by Bio-Argo floats, with concomitant satellite-derived products. The Bio-Argo profiles are representative of the global open-ocean in terms of oceanographic conditions, making the proposed method applicable to most open-ocean environments. SOCA-BBP is validated using 20% of the entire database (global error of 21%). We present additional validation results based on two other independent data sets acquired (1) by four Bio-Argo floats deployed in major oceanic basins, not represented in the database used to train the method; and (2) during an AMT (Atlantic Meridional Transect) field cruise in 2009. These validation tests based on two fully independent data sets indicate the robustness of the predicted vertical distribution of bbp. To illustrate the potential of the method, we merged monthly climatological Argo profiles with ocean color products to produce a depth-resolved climatology of bbp for the global ocean.

  2. Reevaluation of plate motion models based on hotspot tracks in the Atlantic and Indian Oceans

    SciTech Connect

    Baksi, A.K.

    1999-01-01

    Plate motion models based on hotspot tracks in the Atlantic and Indian Oceans predict minimal movement (less than a few millimeters per year) between these hotspots and their counterparts in the Pacific Ocean for the past {approximately}100 m.yr., whereas plate circuit exercises indicate relative motions of {approximately}20 mm/yr. Hotspot-based models also suggest that the Rajmahal Traps, India, were located {approximately}1,000 km away from the Kerguelen hotspot at {approximately}115 Ma, and the Deccan Traps, India, were located a similar distance from the Reunion hotspot at {approximately}65 Ma; this is at odds with conclusions derived from paleomagnetism, plate circuits, and geochemical parameters that suggest a genetic link between flood basalt provinces in India and hotspots in the Indian Ocean. These divergent views may be explained by plume action {approximately}1,000 km from its center or errors in the hotspot motion models. The latter hypothesis is scrutinized in this article by examination of the radiometric ages for hotspot tracks in the Atlantic and Indian Oceans. The {sup 40}/{sup 39}Ar step-heating data for rocks defining the tracks of the Reunion and Kerguelen hotspots in the Indian Ocean and the Great Metero and Tristan da Cunha hotspots in the Atlantic Ocean are critically reexamined. Of {approximately}35 such ages utilized for deriving plate motion models for the past 130 m.yr., at best, only three ({approximately}32, {approximately}50, and {approximately}52 Ma) in the Indian Ocean and one ({approximately}65 Ma) for the Atlantic Ocean may be treated as crystallization ages. Conclusions based on hotspot track modeling for Late Cretaceous to Eocene time are suspect, and those for the Early to Late Cretaceous period are untenable. In the absence of precise age data for the tracks of hotspots in the Atlantic and Indian Oceans, and inconsistent age progressions noted within a single volcanic chain, plate circuit models serve as the superior technique

  3. Benefits of Informal Learning Environments: A Focused Examination of STEM-Based Program Environments

    ERIC Educational Resources Information Center

    Denson, Cameron D.; Austin Stallworth, Chandra; Hailey, Christine; Householder, Daniel L.

    2015-01-01

    This paper examines STEM-based informal learning environments for underrepresented students and reports on the aspects of these programs that are beneficial to students. This qualitative study provides a nuanced look into informal learning environments and determines what is unique about these experiences and makes them beneficial for students. We…

  4. A global ocean inventory of anthropogenic mercury based on water column measurements.

    PubMed

    Lamborg, Carl H; Hammerschmidt, Chad R; Bowman, Katlin L; Swarr, Gretchen J; Munson, Kathleen M; Ohnemus, Daniel C; Lam, Phoebe J; Heimbürger, Lars-Eric; Rijkenberg, Micha J A; Saito, Mak A

    2014-08-01

    Mercury is a toxic, bioaccumulating trace metal whose emissions to the environment have increased significantly as a result of anthropogenic activities such as mining and fossil fuel combustion. Several recent models have estimated that these emissions have increased the oceanic mercury inventory by 36-1,313 million moles since the 1500s. Such predictions have remained largely untested owing to a lack of appropriate historical data and natural archives. Here we report oceanographic measurements of total dissolved mercury and related parameters from several recent expeditions to the Atlantic, Pacific, Southern and Arctic oceans. We find that deep North Atlantic waters and most intermediate waters are anomalously enriched in mercury relative to the deep waters of the South Atlantic, Southern and Pacific oceans, probably as a result of the incorporation of anthropogenic mercury. We estimate the total amount of anthropogenic mercury present in the global ocean to be 290 ± 80 million moles, with almost two-thirds residing in water shallower than a thousand metres. Our findings suggest that anthropogenic perturbations to the global mercury cycle have led to an approximately 150 per cent increase in the amount of mercury in thermocline waters and have tripled the mercury content of surface waters compared to pre-anthropogenic conditions. This information may aid our understanding of the processes and the depths at which inorganic mercury species are converted into toxic methyl mercury and subsequently bioaccumulated in marine food webs. PMID:25100482

  5. Android Based Mobile Environment for Moodle Users

    ERIC Educational Resources Information Center

    de Clunie, Gisela T.; Clunie, Clifton; Castillo, Aris; Rangel, Norman

    2013-01-01

    This paper is about the development of a platform that eases, throughout Android based mobile devices, mobility of users of virtual courses at Technological University of Panama. The platform deploys computational techniques such as "web services," design patterns, ontologies and mobile technologies to allow mobile devices communicate…

  6. Laser-based display technology development at the Naval Ocean Systems Center

    NASA Astrophysics Data System (ADS)

    Phillips, Thomas E.; Trias, John A.; Lasher, Mark E.; Poirier, Peter M.; Dahlke, Weldon J.; Robinson, Waldo R.

    1991-02-01

    For several years, the Naval Ocean Systems Center (NOSC) has been working on the development of laser-based display systems with the goal of upgrading the image quality and ruggedness of shipboard displays. In this paper the authors report work on the major task of developing a full-color laser-addressed liquid crystal light valve (LCLV) projection system.

  7. Laser-based display technology development at the Naval Ocean Systems Center (NOSC)

    NASA Astrophysics Data System (ADS)

    Phillips, Thomas; Trias, John; Lasher, Mark; Poirier, Peter; Dahlke, Weldon

    1991-05-01

    For several years, the Naval Ocean Systems Center (NOSC) has been working on the development of laser-based display systems with the goal of upgrading the image quality and ruggedness of shipboard displays. In this paper we report work on our major task of developing a full-color laser-addressed liquid crystal light value (LCLV) projection system.

  8. Oceanic Flights and Airspace: Improving Efficiency by Trajectory-Based Operations

    NASA Technical Reports Server (NTRS)

    Fernandes, Alicia Borgman; Rebollo, Juan; Koch, Michael

    2016-01-01

    Oceanic operations suffer from multiple inefficiencies, including pre-departure planning that does not adequately consider uncertainty in the proposed trajectory, restrictions on the routes that a flight operator can choose for an oceanic crossing, time-consuming processes and procedures for amending en route trajectories, and difficulties exchanging data between Flight Information Regions (FIRs). These inefficiencies cause aircraft to fly suboptimal trajectories, burning fuel and time that could be conserved. A concept to support integration of existing and emerging capabilities and concepts is needed to transition to an airspace system that employs Trajectory Based Operations (TBO) to improve efficiency and safety in oceanic operations. This paper describes such a concept and the results of preliminary activities to evaluate the concept, including a stakeholder feedback activity, user needs analysis, and high level benefits analysis.

  9. A comparative study of the particulate trace element geochemistry in two contrasting ocean margin environments in the Northeastern Atlantic

    NASA Astrophysics Data System (ADS)

    Chou, L.; Wollast, R.; Roevros, N.

    2003-04-01

    The present study was conducted during the Phases I and II of the Ocean Margin EXchange (OMEX) project, supported by the European Union in the framework of the MAST programme. The objective was to characterise the suspended matter by its composition with emphasis on trace elements in order to evaluate the sources, biogeochemical behaviour in the water column and fate of particulate material in two contrasting ocean margin environments: the Biscay margin and the Iberian margin. The Biscay margin is bordered by a wide continental plateau and a steep continental slope and rise, and is characterised by strong internal tides among many other physical processes with limited riverine input. In contrast, the Iberian margin is characterised by a narrow continental plateau receiving regularly continental input and by seasonal upwelling/downwelling that could influence significantly the chemical composition, transport and fluxes of particles in this region. Suspended matter in the water column along the two margins was sampled by various methods. These include 1) continuous centrifugation of surface waters, 2) in-situ filtration of large volumes of water at various depths using Stand Alone Pumps (SAPs), and 3) sediment traps. In addition to trace elements (Cr, Co, Ni, Cu, Zn Cd, Pb), the chemical composition of particulate matter collected was determined for major (Si, Al, Fe, Ca, POC/PN) and minor (Mg, Na, K, Mn) elements. Centrifugation samples allow the determination of the composition of surface suspended matter dominated by phytoplankton. SAP samples permit the assessment of the vertical evolution of suspended matter composition in the water column. Settling material intercepted by the sediment traps, are associated with large particles such as faecal pellets, marine snow and other aggregates. Trace metal geochemistry of the particulate matter in relation to the carbon cycle will be compared in the two margin environments investigated. Processes affecting the transfer

  10. Molecular and dissociation studies of natural gas hydrates collected from different oceanic environments

    NASA Astrophysics Data System (ADS)

    Bourry, C.; Charlou, J.; Donval, J.; Focsa, C.; Chazallon, B.

    2007-12-01

    is investigated by Raman spectroscopy at atmospheric pressure from 77 K to 260 K. Td shows to depend on the size of the hydrate particles. It is found to increase as the particle size increases. These results are consistent with previous data reported by Takeya et al. (2005). A "multi-layer" dissociation mechanism can be established for large hydrate particles thanks to the high spatial resolution of the micro-Raman technique. This effect will be discussed in the context of the stability of hydrates in natural environments. Takeya et al. (2005), Particle size effect of CH4 hydrate for self-preservation, Chem. Eng. Sci., 60, 1383-1387.

  11. Teaching Sustainabilty in the Setting of a Field-based Class on the Oceans in Captivity

    NASA Astrophysics Data System (ADS)

    Macko, Stephen; Tuite, Michael; O'Connell, Matthew

    2013-04-01

    Sustainability awareness is increasingly a subject in educational settings. Marine science classes are perfect settings of establishing sustainability awareness owing to declining populations of organisms and perceived collapsenin fisheries worldwide. Students in oceanography classes often request more direct exposure to actual ocean situations or field trips. During regular session (13 week) or shorter term (4 week) summer classes such long trips are logistically difficult owing to large numbers of students involved or timing. This new approach to such a course supplement addresses the requests by utilizing local resources and short field trips for a limited number of students (20) to locations in which Ocean experiences are available, and are often supported through education and outreach components. The vision of the class was a mixture of classroom time, readings, along with paper and laboratories. In addition short day-long trips to locations where the ocean was "captured" were also used to supplement the experience as well as speakers involved with aquaculture ("cultivated") Central Virginia is a fortunate location for such a class, with close access for "day travel" to the Chesapeake Bay and numerous field stations, museums with ocean-based exhibits (the Smithsonian and National Zoo) that address both extant and extinct Earth history, as well as national/state aquaria in Baltimore, Washington and Virginia Beach. Furthermore, visits to local seafood markets at local grocery stores, or larger city markets) enhance the exposure to productivity in the ocean, and viability of the fisheries sustainability. The course could then address not only the particulars of the marine science, but also aspects of sustainability with discussions on ethics, including keeping animals in captivity or overfishing of particular species and the special difficulties that arise from captive or culturing ocean populations. In addition, the class was encouraged to post web-based

  12. Applications of satellite and marine geodesy to operations in the ocean environment

    NASA Technical Reports Server (NTRS)

    Fubara, D. M.; Mourad, A. G.

    1975-01-01

    The requirements for marine and satellite geodesy technology are assessed with emphasis on the development of marine geodesy. Various programs and missions for identification of the satellite geodesy technology applicable to marine geodesy are analyzed along with national and international marine programs to identify the roles of satellite/marine geodesy techniques for meeting the objectives of the programs and other objectives of national interest effectively. The case for marine geodesy is developed based on the extraction of requirements documented by authoritative technical industrial people, professional geodesists, government agency personnel, and applicable technology reports.

  13. Mapping Arctic Ocean Coastline Change With Landsat Archive Data And Object-Based Image Analysis

    NASA Astrophysics Data System (ADS)

    Hulslander, D.

    2010-12-01

    The melting of arctic permafrost is a significant effect of climate change. The combination of rising sea level, longer periods of ice-free conditions in the Arctic Ocean and melting permafrost can greatly accelerate coastline changes in general and arctic coastal erosion in particular. Anderson et al. (2009; Geology News) have measured erosion rates of 15 m per year at sites along the Alaskan Arctic Ocean coastline dominated by ice-cemented peats and silt-rich permafrost. With over 45,000 km of Arctic Ocean coastline, it is important that coastline movement and transgressive oceanic regimes be mapped and tracked with accurate data. Determining historic coastal erosion rates for this region is as important as mapping the current extent of the phenomenon to create as complete a picture as possible and locate where rapid erosion is an emergent process. The extent of the area involved combined with its inaccessibility and inhospitable conditions makes geologic remote sensing an appropriate tool for characterizing Arctic Ocean coastal erosion. Traditional weaknesses associated with using remote sensing in the geosciences have included a lack of historical data or baseline information as well as difficulties in systematization of feature mapping. Using object-based image analysis on Landsat archive data can overcome these issues and may allow for a potential multi-decadal map of Arctic Ocean coastline changes. The Landsat family of sensors (MSS 1-3 and TM/ETM 4, 5, and 7) have been providing imagery as frequently as every 16 days since July 1972. The frequent revisits maximize the chance of getting cloud-free imagery at least once per year in most study areas. Also, Landsat data are well characterized, extensively studied, and freely available from the USGS EROS Data Center Archive, making it an ideal and stable source of data for mapping the Arctic Ocean coastline. Delineating large sections of coastline from imagery by hand digitization would be impractical due to the

  14. Mooring system of ocean turbulence observation based on submerged buoy

    NASA Astrophysics Data System (ADS)

    Song, Da-lei; Sun, Jing-jing; Xue, Bing; Jiang, Qian-li; Wu, Bing-wei

    2013-06-01

    A comparison experiment has been taken in the Kiaochow Bay between a newly designed mooring turbulence observation instrument (MTOI) and microstructure profiler MSS60 made by Sea & Sun. The whole observing system is based on a submerged buoy, in which the turbulence observation instrument is embedded, with a streamline-shape floating body, which is made of buoyancy material of glass microsphere. For the movement of seawater and the cable shaking strongly anytime influence the behaviors of the floating body, the accelerate sensors are used for the vibration measurement in the instrument together with the shear probe sensor. Both the vibration data and the shear data are acquired by the instrument at the same time. During data processing, the vibration signals can be removed and leave the shear data which we really need. In order to prove the reliability of the new turbulence instrument MTOI, a comparison experiment was designed. The measuring conditions are the same both in time and space. By this way, the two groups of data are comparable. In this paper, the conclusion gives a good similarity of 0.93 for the two groups of shear data in dissipation rate. The processing of the data acquired by MTOI is based on the cross-spectrum analysis, and the dissipation rate of it matches the Nasmyth spectrum well.

  15. A knowledge based software engineering environment testbed

    NASA Technical Reports Server (NTRS)

    Gill, C.; Reedy, A.; Baker, L.

    1985-01-01

    The Carnegie Group Incorporated and Boeing Computer Services Company are developing a testbed which will provide a framework for integrating conventional software engineering tools with Artifical Intelligence (AI) tools to promote automation and productivity. The emphasis is on the transfer of AI technology to the software development process. Experiments relate to AI issues such as scaling up, inference, and knowledge representation. In its first year, the project has created a model of software development by representing software activities; developed a module representation formalism to specify the behavior and structure of software objects; integrated the model with the formalism to identify shared representation and inheritance mechanisms; demonstrated object programming by writing procedures and applying them to software objects; used data-directed and goal-directed reasoning to, respectively, infer the cause of bugs and evaluate the appropriateness of a configuration; and demonstrated knowledge-based graphics. Future plans include introduction of knowledge-based systems for rapid prototyping or rescheduling; natural language interfaces; blackboard architecture; and distributed processing

  16. Ocean-generated magnetic field study based on satellite geomagnetic measurements: 2. Signal inference

    NASA Astrophysics Data System (ADS)

    Golubev, Yury

    2012-09-01

    The work presented here is the second part of an ocean-generated magnetic field study and provides a procedure for inferring the ocean-generated magnetic field from satellite geomagnetic measurements. The procedure was first tested on synthetic data. The simulation employed a hypothetical satellite measuring the magnetic field at an altitude of 400 km. The “measurements” (generated by the CM4 and CHAOS models) included the core field, the lithospheric field, the ionospheric and magnetospheric fields, the secular variation, and the ocean-generated magnetic field. The search algorithm, as proposed in part 1, converts irregular measurements into fields on a regular grid. The filtration procedure is based on the Savitzky-Golay algorithm. The procedure includes four steps providing seven unknown filter parameters. Parameter values were obtained by solving the problem of minimizing the spatially averaged squared residuals between the inferred field and the model field. Then, the parameters were used in the filter to infer the ocean-generated magnetic field that was initially added to the “measurements.” The inferred signal, although spatially corrupted and having a smaller magnitude (60% of the magnitude of the initial signal), indicated the presence of magnetic anomalies within the Southern Ocean. The technique was then applied to CHAMP geomagnetic measurements. The result of filtering was clear magnetic anomalies within the Southern Ocean with a spatial character that were close to what models of the ocean-generated magnetic field provided. The magnitude of the inferring signal was 5 nT, the corrected values were 7-8 nT, 1-2 nT larger than the modeled field magnitude. To compare the temporal variability of the inferred field with the variability of sea surface height, ten 10° by 10° areas were selected within the Southern Ocean and the root-mean-square of both SSH and the magnetic field were computed for each area. A comparison of the results indicated a

  17. 33 CFR 334.900 - Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.900 Section 334.900 Navigation and Navigable Waters... REGULATIONS § 334.900 Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. (a)...

  18. 33 CFR 334.900 - Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.900 Section 334.900 Navigation and Navigable Waters... REGULATIONS § 334.900 Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. (a)...

  19. 33 CFR 334.900 - Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.900 Section 334.900 Navigation and Navigable Waters... REGULATIONS § 334.900 Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. (a)...

  20. 33 CFR 334.900 - Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.900 Section 334.900 Navigation and Navigable Waters... REGULATIONS § 334.900 Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. (a)...

  1. 33 CFR 334.900 - Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.900 Section 334.900 Navigation and Navigable Waters... REGULATIONS § 334.900 Pacific Ocean, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. (a)...

  2. Studies of Ocean Predictability at Decade to Century Time Scales Using a Global Ocean General Circulation Model in a Parallel Computing Environment

    SciTech Connect

    Barnett, T.P.

    1998-11-30

    The objectives of this report are to determine the structure of oceanic natural variability at time scales of decades to centuries, characterize the physical mechanisms responsible for the variability; determine the relative importance of heat, fresh water, and moment fluxes on the variability; determine the predictability of the variability on these times scales. (B204)

  3. EVA: Collaborative Distributed Learning Environment Based in Agents.

    ERIC Educational Resources Information Center

    Sheremetov, Leonid; Tellez, Rolando Quintero

    In this paper, a Web-based learning environment developed within the project called Virtual Learning Spaces (EVA, in Spanish) is presented. The environment is composed of knowledge, collaboration, consulting, experimentation, and personal spaces as a collection of agents and conventional software components working over the knowledge domains. All…

  4. Using Design-Based Research in Informal Environments

    ERIC Educational Resources Information Center

    Reisman, Molly

    2008-01-01

    Design-Based Research (DBR) has been a tool of the learning sciences since the early 1990s, used as a way to improve and study learning environments. Using an iterative process of design with the goal of reining theories of learning, researchers and educators now use DBR seek to identify "how" to make a learning environment work. They then draw…

  5. EVA: An Interactive Web-Based Collaborative Learning Environment

    ERIC Educational Resources Information Center

    Sheremetov, Leonid; Arenas, Adolfo Guzman

    2002-01-01

    In this paper, a Web-based learning environment developed within the project called Virtual Learning Spaces (EVA, in Spanish) is described. The environment is composed of knowledge, collaboration, consulting and experimentation spaces as a collection of agents and conventional software components working over the knowledge domains. All user…

  6. Web-Based Interactive Writing Environment: Development and Evaluation

    ERIC Educational Resources Information Center

    Yang, Jie Chi; Ko, Hwa Wei; Chung, I. Ling

    2005-01-01

    This study reports the development and evaluation of a web-based interactive writing environment designed for elementary school students. The environment includes three writing themes, "story pass on", "story chameleon" and "thousand ideas", to encourage reading comprehension, creativity and problem-solving skills of students. Three assessment…

  7. Global Ocean Surveillance With Electronic Intelligence Based Satellite System

    NASA Astrophysics Data System (ADS)

    Venkatramanan, Haritha

    2016-07-01

    The objective of this proposal is to design our own ELINT based satellite system to detect and locate the target by using satellite Trilateration Principle. The target position can be found by measuring the radio signals arrived at three satellites using Time Difference of Arrival(TDOA) technique. To locate a target it is necessary to determine the satellite position. The satellite motion and its position is obtained by using Simplified General Perturbation Model(SGP4) in MATLAB. This SGP4 accepts satellite Two Line Element(TLE) data and returns the position in the form of state vectors. These state vectors are then converted into observable parameters and then propagated in space. This calculations can be done for satellite constellation and non - visibility periods can be calculated. Satellite Trilateration consists of three satellites flying in formation with each other. The satellite constellation design consists of three satellites with an inclination of 61.3° maintained at equal distances between each other. The design is performed using MATLAB and simulated to obtain the necessary results. The target's position can be obtained using the three satellites ECEF Coordinate system and its position and velocity can be calculated in terms of Latitude and Longitude. The target's motion is simulated to obtain the Speed and Direction of Travel.

  8. Assessment of Urbanization on the Integrated Land-Ocean-Atmosphere Environment in Coastal Metropolis in Preparation for HyspIRI

    NASA Technical Reports Server (NTRS)

    Sequera, Pedro; McDonald, Kyle C.; Gonzalez, Jorge; Arend, Mark; Krakauer, Nir; Bornstein, Robert; Luvll, Jeffrey

    2012-01-01

    The need for comprehensive studies of the relationships between past and projected changes of regional climate and human activity in comple x urban environments has been well established. The HyspIRI preparato ry airborne activities in California, associated science and applicat ions research, and eventually HyspIRI itself provide an unprecedented opportunity for development and implementation of an integrated data and modeling analysis system focused on coastal urban environments. We will utilize HyspIRI preparatory data collections in developing ne w remote sensing-based tools for investigating the integrated urban e nvironment, emphasizing weather, climate, and energy demands in compl ex coastal cities.

  9. A Design and Control Environment for Internet-Based Telerobotics

    NASA Technical Reports Server (NTRS)

    Oboe, Roberto; Fiorini, Paolo

    1997-01-01

    This paper describes an environment for the design, simulation and control of Internet-based force-relflecting telerobotc systems. We define these systems as using a segment of the computer network to connect the master to the slave.

  10. Toward a global ocean data assimilation system based on ensemble optimum interpolation: altimetry data assimilation experiment

    NASA Astrophysics Data System (ADS)

    Fu, Weiwei; Zhu, Jiang; Yan, Changxiang; Liu, Hailong

    2009-08-01

    A global ocean data assimilation system based on the ensemble optimum interpolation (EnOI) has been under development as the Chinese contribution to the Global Ocean Data Assimilation Experiment. The system uses a global ocean general circulation model, which is eddy permitting, developed by the Institute of Atmospheric Physics of the Chinese Academy of Sciences. In this paper, the implementation of the system is described in detail. We describe the sampling strategy to generate the stationary ensembles for EnOI. In addition, technical methods are introduced to deal with the requirement of massive memory space to hold the stationary ensembles of the global ocean. The system can assimilate observations such as satellite altimetry, sea surface temperature (SST), in situ temperature and salinity from Argo, XBT, Tropical Atmosphere Ocean (TAO), and other sources in a straightforward way. As a first step, an assimilation experiment from 1997 to 2001 is carried out by assimilating the sea level anomaly (SLA) data from TOPEX/Poseidon. We evaluate the performance of the system by comparing the results with various types of observations. We find that SLA assimilation shows very positive impact on the modeled fields. The SST and sea surface height fields are clearly improved in terms of both the standard deviation and the root mean square difference. In addition, the assimilation produces some improvements in regions where mesoscale processes cannot be resolved with the horizontal resolution of this model. Comparisons with TAO profiles in the Pacific show that the temperature and salinity fields have been improved to varying degrees in the upper ocean. The biases with respect to the independent TAO profiles are reduced with a maximum magnitude of about 0.25°C and 0.1 psu for the time-averaged temperature and salinity. The improvements on temperature and salinity also lead to positive impact on the subsurface currents. The equatorial under current is enhanced in the Pacific

  11. Design-Based Research and Technology-Enhanced Learning Environments

    ERIC Educational Resources Information Center

    Wang, Feng; Hannafin, Michael J.

    2005-01-01

    During the past decade, design-based research has demonstrated its potential as a methodology suitable to both research and design of technology-enhanced learning environments (TELEs). In this paper, we define and identify characteristics of design-based research, describe the importance of design-based research for the development of TELEs,…

  12. Accuracy assessment of the global ionospheric model over the Southern Ocean based on dynamic observation

    NASA Astrophysics Data System (ADS)

    Luo, xiaowen

    2016-04-01

    The global ionospheric model based on the reference stations of the Global Navigation Satellite System (GNSS) of the International GNSS Services is presently the most commonly used products of the global ionosphere. It is very important to comprehensively analyze and evaluate the accuracy and reliability of the model for the reasonable use of this kind of ionospheric product. This work is different to the traditional performance evaluation of the global ionosphere model based on observation data of ground-based static reference stations. The preliminary evaluation and analysis of the the global ionospheric model was conducted with the dynamic observation data across different latitudes over the southern oceans. The validation results showed that the accuracy of the global ionospheric model over the southern oceans is about 5 TECu, which deviates from the measured ionospheric TEC by about -0.6 TECu.

  13. NEMO-Nordic : A NEMO based ocean modelling configuration for Baltic & North Seas

    NASA Astrophysics Data System (ADS)

    Hordoir, Robinson; Schimanke, Semjon; Axell, Lars; Gröger, Matthias; Dieterich, Christian; Liu, Ye; Höglund, Anders; Kuznetsov, Ivan; Ljungemyr, Patrik; Nygren, Petter; Jönsson, Anette; Meier, Markus

    2015-04-01

    Based on the NEMO ocean engine, three regional setups for the North Sea and Baltic Sea domain have been developed : the NEMO-Nordic configuration is declined in an operational setup, a stand-alone version used for climate and process studies, and a NEMO-Nordic-RCA4 atmosphere/ocean coupled configuration used for downscalling climate scenarios. We give a brief overview of the options chosen within the NEMO engine to design the configurations. Based on the results provided by each of the three configurations, we also provide an assessment of the strengths and weaknesses of NEMO-Nordic. Finally, a validation of the configurations is provided based on an extensive comparison between in-situ measurements and model results for temperature, salinity, sea-ice extent, sea level and mean circulation.

  14. NIR- and SWIR-based on-orbit vicarious calibrations for satellite ocean color sensors.

    PubMed

    Wang, Menghua; Shi, Wei; Jiang, Lide; Voss, Kenneth

    2016-09-01

    The near-infrared (NIR) and shortwave infrared (SWIR)-based atmospheric correction algorithms are used in satellite ocean color data processing, with the SWIR-based algorithm particularly useful for turbid coastal and inland waters. In this study, we describe the NIR- and two SWIR-based on-orbit vicarious calibration approaches for satellite ocean color sensors, and compare results from these three on-orbit vicarious calibrations using satellite measurements from the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP). Vicarious calibration gains for VIIRS spectral bands are derived using the in situ normalized water-leaving radiance nLw(λ) spectra from the Marine Optical Buoy (MOBY) in waters off Hawaii. The SWIR vicarious gains are determined using VIIRS measurements from the South Pacific Gyre region, where waters are the clearest and generally stable. Specifically, vicarious gain sets for VIIRS spectral bands of 410, 443, 486, 551, and 671 nm derived from the NIR method using the NIR 745 and 862 nm bands, the SWIR method using the SWIR 1238 and 1601 nm bands, and the SWIR method using the SWIR 1238 and 2257 nm bands are (0.979954, 0.974892, 0.974685, 0.965832, 0.979042), (0.980344, 0.975344, 0.975357, 0.965531, 0.979518), and (0.980820, 0.975609, 0.975761, 0.965888, 0.978576), respectively. Thus, the NIR-based vicarious calibration gains are consistent with those from the two SWIR-based approaches with discrepancies mostly within ~0.05% from three data processing methods. In addition, the NIR vicarious gains (745 and 862 nm) derived from the two SWIR methods are (0.982065, 1.00001) and (0.981811, 1.00000), respectively, with the difference ~0.03% at the NIR 745 nm band. This is the fundamental basis for the NIR-SWIR combined atmospheric correction algorithm, which has been used to derive improved satellite ocean color products over open oceans and turbid coastal/inland waters. Therefore, a unified

  15. Oceanic Observations

    NASA Technical Reports Server (NTRS)

    Busalacchi, Antonio J.

    1997-01-01

    For many years, merchant ships and the naval fleets of various countries have been the major source of data over and in the open ocean. Oceanographic research experiments and process studies in the field have also contributed to the climatological data bases for the global ocean, but, for the most part, these have been limited in duration and extent. However, over the last 10 years under the auspices of the World Climate Research Program and the International Geosphere Biosphere Program the role of the oceans in global and climate change has taken on increased significance. This has created a need for a considerably improved understanding of the seasonal, interannual, decadal and longer time-scale variability of the physical and biogeochemical attributes of the global ocean. As a result, over the past 10 years several major international field programs have been implemented and have had a tremendous impact on the number of in situ observations obtained for the global ocean. The Tropical Ocean Global Atmosphere (TOGA) program, the World Ocean Circulation Experiment (WOCE), and the Joint Global Ocean Flux Study (JGOFS) were designed with observational, modelling, and process study components aimed at analyzing different aspects of the ocean's role in the coupled climate system. In parallel with the field programs, continuous space-based observations of sea surface temperature, sea surface topography, and sea surface winds spanning nearly a decade or longer have become a reality. During this same time period, numerical ocean models and computational power have advanced to the point where the oceanographic observations, both in situ and remotely sensed, can be assimilated into numerical ocean models in order to provide a four-dimensional (x-y-z-t) depiction of the evolving state of the global ocean.

  16. Local Observations, Global Connections: An Educational Program Using Ocean Networks Canada's Community-Based Observatories

    NASA Astrophysics Data System (ADS)

    Pelz, M.; Hoeberechts, M.; Ewing, N.; Davidson, E.; Riddell, D. J.

    2014-12-01

    Schools on Canada's west coast and in the Canadian Arctic are participating in the pilot year of a novel educational program based on analyzing, understanding and sharing ocean data collected by cabled observatories. The core of the program is "local observations, global connections." First, students develop an understanding of ocean conditions at their doorstep through the analysis of community-based observatory data. Then, they connect that knowledge with the health of the global ocean by engaging with students at other schools participating in the educational program and through supplemental educational resources. Ocean Networks Canada (ONC), an initiative of the University of Victoria, operates cabled ocean observatories which supply continuous power and Internet connectivity to a broad suite of subsea instruments from the coast to the deep sea. This Internet connectivity permits researchers, students and members of the public to download freely available data on their computers anywhere around the globe, in near real-time. In addition to the large NEPTUNE and VENUS cabled observatories off the coast of Vancouver Island, British Columbia, ONC has been installing smaller, community-based cabled observatories. Currently two are installed: one in Cambridge Bay, Nunavut and one at Brentwood College School, on Mill Bay in Saanich Inlet, BC. Several more community-based observatories are scheduled for installation within the next year. The observatories support a variety of subsea instruments, such as a video camera, hydrophone and water quality monitor and shore-based equipment including a weather station and a video camera. Schools in communities hosting an observatory are invited to participate in the program, alongside schools located in other coastal and inland communities. Students and teachers access educational material and data through a web portal, and use video conferencing and social media tools to communicate their findings. A series of lesson plans

  17. Web-based visualization of gridded dataset usings OceanBrowser

    NASA Astrophysics Data System (ADS)

    Barth, Alexander; Watelet, Sylvain; Troupin, Charles; Beckers, Jean-Marie

    2015-04-01

    OceanBrowser is a web-based visualization tool for gridded oceanographic data sets. Those data sets are typically four-dimensional (longitude, latitude, depth and time). OceanBrowser allows one to visualize horizontal sections at a given depth and time to examine the horizontal distribution of a given variable. It also offers the possibility to display the results on an arbitrary vertical section. To study the evolution of the variable in time, the horizontal and vertical sections can also be animated. Vertical section can be generated by using a fixed distance from coast or fixed ocean depth. The user can customize the plot by changing the color-map, the range of the color-bar, the type of the plot (linearly interpolated color, simple contours, filled contours) and download the current view as a simple image or as Keyhole Markup Language (KML) file for visualization in applications such as Google Earth. The data products can also be accessed as NetCDF files and through OPeNDAP. Third-party layers from a web map service can also be integrated. OceanBrowser is used in the frame of the SeaDataNet project (http://gher-diva.phys.ulg.ac.be/web-vis/) and EMODNET Chemistry (http://oceanbrowser.net/emodnet/) to distribute gridded data sets interpolated from in situ observation using DIVA (Data-Interpolating Variational Analysis).

  18. Event Detection and Visualization of Ocean Eddies based on SSH and Velocity Field

    NASA Astrophysics Data System (ADS)

    Matsuoka, Daisuke; Araki, Fumiaki; Inoue, Yumi; Sasaki, Hideharu

    2016-04-01

    Numerical studies of ocean eddies have been progressed using high-resolution ocean general circulation models. In order to understand ocean eddies from simulation results with large amount of information volume, it is necessary to visualize not only distribution of eddies of each time step, but also events or phenomena of eddies. However, previous methods cannot precisely detect eddies, especially, during the events such as eddies' amalgamation, bifurcation. In the present study, we propose a new approach of eddy's detection, tracking and event visualization based on sea surface height (SSH) and velocity field. The proposed method detects eddies region as well as streams and currents region, and classifies detected eddies into several types. By tracking the time-varying change of classified eddies, it is possible to detect not only eddies event such as amalgamation and bifurcation but also the interaction between eddy and ocean current. As a result of visualizing detected eddies and events, we succeeded in creating the movie which enables us to intuitively understand the region of interest.

  19. Knowledge-based systems and NASA's software support environment

    NASA Technical Reports Server (NTRS)

    Dugan, Tim; Carmody, Cora; Lennington, Kent; Nelson, Bob

    1990-01-01

    A proposed role for knowledge-based systems within NASA's Software Support Environment (SSE) is described. The SSE is chartered to support all software development for the Space Station Freedom Program (SSFP). This includes support for development of knowledge-based systems and the integration of these systems with conventional software systems. In addition to the support of development of knowledge-based systems, various software development functions provided by the SSE will utilize knowledge-based systems technology.

  20. 33 CFR 334.910 - Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.910 Section 334.910... AND RESTRICTED AREA REGULATIONS § 334.910 Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine...

  1. 33 CFR 334.910 - Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.910 Section 334.910... AND RESTRICTED AREA REGULATIONS § 334.910 Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine...

  2. 33 CFR 334.910 - Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.910 Section 334.910... AND RESTRICTED AREA REGULATIONS § 334.910 Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine...

  3. 33 CFR 334.910 - Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.910 Section 334.910... AND RESTRICTED AREA REGULATIONS § 334.910 Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine...

  4. 33 CFR 334.910 - Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine Corps Base, Camp Pendleton, Calif.; restricted area. 334.910 Section 334.910... AND RESTRICTED AREA REGULATIONS § 334.910 Pacific Ocean, Camp Pendleton Boat Basin, U.S. Marine...

  5. 75 FR 26100 - Danger Zone, Pacific Ocean, Naval Base Coronado, Coronado, California

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-11

    ...The U.S. Army Corps of Engineers (Corps) is amending its regulations to establish a naval danger zone in the waters of the Pacific Ocean extending offshore from the small arms range at the Naval Base Coronado (NBC), in Coronado, San Diego County, California. The danger zone will provide an appropriate and enforceable zone in which the Navy may conduct small arms test firing to qualify military......

  6. Ammonia-oxidizing bacterial community composition in estuarine and oceanic environments assessed using a functional gene microarray

    USGS Publications Warehouse

    Ward, B.B.; Eveillard, D.; Kirshtein, J.D.; Nelson, J.D.; Voytek, M.A.; Jackson, G.A.

    2007-01-01

    The relationship between environmental factors and functional gene diversity of ammonia-oxidizing bacteria (AOB) was investigated across a transect from the freshwater portions of the Chesapeake Bay and Choptank River out into the Sargasso Sea. Oligonucleotide probes (70-bp) designed to represent the diversity of ammonia monooxygenase (amoA) genes from Chesapeake Bay clone libraries and cultivated AOB were used to construct a glass slide microarray. Hybridization patterns among the probes in 14 samples along the transect showed clear variations in amoA community composition. Probes representing uncultivated members of the Nitrosospira-like AOB dominated the probe signal, especially in the more marine samples. Of the cultivated species, only Nitrosospira briensis was detected at appreciable levels. Discrimination analysis of hybridization signals detected two guilds. Guild 1 was dominated by the marine Nitrosospira-like probe signal, and Guild 2???s largest contribution was from upper bay (freshwater) sediment probes. Principal components analysis showed that Guild 1 was positively correlated with salinity, temperature and chlorophyll a concentration, while Guild 2 was positively correlated with concentrations of oxygen, dissolved organic carbon, and particulate nitrogen and carbon, suggesting that different amoA sequences represent organisms that occupy different ecological niches within the estuarine/marine environment. The trend from most diversity of AOB in the upper estuary towards dominance of a single type in the polyhaline region of the Bay is consistent with the declining importance of AOB with increasing salinity, and with the idea that AO-Archaea are the more important ammonia oxidizers in the ocean. ?? 2007 The Authors.

  7. Ammonia-oxidizing bacterial community composition in estuarine and oceanic environments assessed using a functional gene microarray.

    PubMed

    Ward, Bess B; Eveillard, Damien; Kirshtein, Julie D; Nelson, Joshua D; Voytek, Mary A; Jackson, George A

    2007-10-01

    The relationship between environmental factors and functional gene diversity of ammonia-oxidizing bacteria (AOB) was investigated across a transect from the freshwater portions of the Chesapeake Bay and Choptank River out into the Sargasso Sea. Oligonucleotide probes (70-bp) designed to represent the diversity of ammonia monooxygenase (amoA) genes from Chesapeake Bay clone libraries and cultivated AOB were used to construct a glass slide microarray. Hybridization patterns among the probes in 14 samples along the transect showed clear variations in amoA community composition. Probes representing uncultivated members of the Nitrosospira-like AOB dominated the probe signal, especially in the more marine samples. Of the cultivated species, only Nitrosospira briensis was detected at appreciable levels. Discrimination analysis of hybridization signals detected two guilds. Guild 1 was dominated by the marine Nitrosospira-like probe signal, and Guild 2's largest contribution was from upper bay (freshwater) sediment probes. Principal components analysis showed that Guild 1 was positively correlated with salinity, temperature and chlorophyll a concentration, while Guild 2 was positively correlated with concentrations of oxygen, dissolved organic carbon, and particulate nitrogen and carbon, suggesting that different amoA sequences represent organisms that occupy different ecological niches within the estuarine/marine environment. The trend from most diversity of AOB in the upper estuary towards dominance of a single type in the polyhaline region of the Bay is consistent with the declining importance of AOB with increasing salinity, and with the idea that AO-Archaea are the more important ammonia oxidizers in the ocean. PMID:17803777

  8. Analysis of Navigation in a Problem-Based Learning Environment.

    ERIC Educational Resources Information Center

    Williams, Douglas C.; Liu, Min; Benton, Denise

    Research has shown the potential of a problem-based approach to enhance students' learning. The interactive nature of hypermedia technology and its ability to deliver information in different media formats can provide unique capabilities for implementing problem-based learning (PBL) environments. Yet, little is known about the types of tools that…

  9. Novel two-stage piezoelectric-based ocean wave energy harvesters for moored or unmoored buoys

    NASA Astrophysics Data System (ADS)

    Murray, R.; Rastegar, J.

    2009-03-01

    Harvesting mechanical energy from ocean wave oscillations for conversion to electrical energy has long been pursued as an alternative or self-contained power source. The attraction to harvesting energy from ocean waves stems from the sheer power of the wave motion, which can easily exceed 50 kW per meter of wave front. The principal barrier to harvesting this power is the very low and varying frequency of ocean waves, which generally vary from 0.1Hz to 0.5Hz. In this paper the application of a novel class of two-stage electrical energy generators to buoyant structures is presented. The generators use the buoy's interaction with the ocean waves as a low-speed input to a primary system, which, in turn, successively excites an array of vibratory elements (secondary system) into resonance - like a musician strumming a guitar. The key advantage of the present system is that by having two decoupled systems, the low frequency and highly varying buoy motion is converted into constant and much higher frequency mechanical vibrations. Electrical energy may then be harvested from the vibrating elements of the secondary system with high efficiency using piezoelectric elements. The operating principles of the novel two-stage technique are presented, including analytical formulations describing the transfer of energy between the two systems. Also, prototypical design examples are offered, as well as an in-depth computer simulation of a prototypical heaving-based wave energy harvester which generates electrical energy from the up-and-down motion of a buoy riding on the ocean's surface.

  10. Atmospheric Nitrogen Deposition to the Oceans: Observation- and Model-Based Estimates

    NASA Astrophysics Data System (ADS)

    Baker, Alex

    2016-04-01

    The reactive nitrogen (Nr) burden of the atmosphere has been increased by a factor of 3-4 by anthropogenic activity since the Industrial Revolution. This has led to large increases in the deposition of nitrate and ammonium to the surface waters of the open ocean, particularly downwind of major human population centres, such as those in North America, Europe and Southeast Asia. In oligotrophic waters, this deposition has the potential to significantly impact marine productivity and the global carbon cycle. Global-scale understanding of N deposition to the oceans is reliant on our ability to produce effective models of reactive nitrogen emission, atmospheric chemistry, transport and deposition (including deposition to the land surface). Over land, N deposition models can be assessed using comparisons to regional monitoring networks of precipitation chemistry (notably those located in North America, Europe and Southeast Asia). No similar datasets exist which would allow observation - model comparisons of wet deposition for the open oceans, because long-term wet deposition records are available for only a handful of remote island sites and rain collection over the open ocean itself is logistically very difficult. In this work we attempt instead to use ~2800 observations of aerosol nitrate and ammonium concentrations, acquired from sampling aboard ships in the period 1995 - 2012, to assess the performance of modelled N deposition fields over the remote ocean. This database is non-uniformly distributed in time and space. We selected three ocean regions (the eastern tropical North Atlantic, the northern Indian Ocean and northwest Pacific) where we considered the density and distribution of observational data is sufficient to provide effective comparison to the model ensemble. Our presentation will focus on the eastern tropical North Atlantic region, which has the best data coverage of the three. We will compare dry deposition fluxes calculated from the observed nitrate

  11. Gradation from oceanic to estuarine beaches in a ría environment: A case study in the Ría de Vigo

    NASA Astrophysics Data System (ADS)

    Bernabeu, Ana M.; Lersundi-Kanpistegi, Aimar V.; Vilas, Federico

    2012-05-01

    Beaches are an important consideration in coastal management. Morphodynamic classification of sandy beaches is used for open-ocean, wave-dominated environments, but fails to describe the shape of natural sandy beaches located in low-energy environments. An important consequence of this is that these environments are excluded from current morphodynamic models, making the design of efficient coastal management plans difficult to achieve. Many of these types of beaches occur in quick succession along the coastline in protected environments such as estuaries, lagoons, fjords and rías, which are favourite sites for human settlements. These particular environments are of enormous economic importance and constitute the zones of greatest human impact on the coast. Correct management requires a good understanding of the physical factors that affect each type of beach and of the interactions between such factors. Fifteen beaches in the Ría de Vigo (NW Spain) were studied in order to determine how the gradational changes from oceanic to estuarine conditions affect the beach morphology and intertidal sediments. The balance between wave action and sedimentary supply was found to be the controlling factor in the ría. The results of this study provide useful information about a coastal ría environment, which will enable better design of a suitable integrated coastal plan for management of rías.

  12. Carbon-based phytoplankton size classes retrieved via ocean color estimates of the particle size distribution

    NASA Astrophysics Data System (ADS)

    Kostadinov, T. S.; Milutinović, S.; Marinov, I.; Cabré, A.

    2015-05-01

    Owing to their important roles in biogeochemical cycles, phytoplankton functional types (PFTs) have been the aim of an increasing number of ocean color algorithms. Yet, none of the existing methods are based on phytoplankton carbon (C) biomass, which is a fundamental biogeochemical and ecological variable and the "unit of accounting" in Earth System models. We present a novel bio-optical algorithm to retrieve size-partitioned phytoplankton carbon from ocean color satellite data. The algorithm is based on existing algorithms to estimate particle volume from a power-law particle size distribution (PSD). Volume is converted to carbon concentrations using a compilation of allometric relationships. We quantify absolute and fractional biomass in three PFTs based on size - picophytoplankton (0.5-2 μm in diameter), nanophytoplankton (2-20 μm) and microphytoplankton (20-50 μm). The mean spatial distributions of total phytoplankton C biomass and individual PFTs, derived from global SeaWiFS monthly ocean color data, are consistent with current understanding of oceanic ecosystems, i.e. oligotrophic regions are characterized by low biomass and dominance of picoplankton, whereas eutrophic regions have large biomass to which nanoplankton and microplankton contribute relatively larger fractions. Global spatially integrated phytoplankton carbon biomass standing stock estimates using our PSD-based approach yield on average ~0.2-0.3 Gt of C, consistent with analogous estimates from two other ocean color algorithms, and several state-of-the-art Earth System models. However, the range of phytoplankton C biomass spatial variability globally is larger than estimated by any other models considered here, because the PSD-based algorithm is not a priori empirically constrained and introduces improvement over the assumptions of the other approaches. Satisfactory in situ closure observed between PSD and POC measurements lends support to the theoretical basis of the PSD-based algorithm

  13. Carbon-based phytoplankton size classes retrieved via ocean color estimates of the particle size distribution

    NASA Astrophysics Data System (ADS)

    Kostadinov, Tihomir S.; Milutinović, Svetlana; Marinov, Irina; Cabré, Anna

    2016-04-01

    Owing to their important roles in biogeochemical cycles, phytoplankton functional types (PFTs) have been the aim of an increasing number of ocean color algorithms. Yet, none of the existing methods are based on phytoplankton carbon (C) biomass, which is a fundamental biogeochemical and ecological variable and the "unit of accounting" in Earth system models. We present a novel bio-optical algorithm to retrieve size-partitioned phytoplankton carbon from ocean color satellite data. The algorithm is based on existing methods to estimate particle volume from a power-law particle size distribution (PSD). Volume is converted to carbon concentrations using a compilation of allometric relationships. We quantify absolute and fractional biomass in three PFTs based on size - picophytoplankton (0.5-2 µm in diameter), nanophytoplankton (2-20 µm) and microphytoplankton (20-50 µm). The mean spatial distributions of total phytoplankton C biomass and individual PFTs, derived from global SeaWiFS monthly ocean color data, are consistent with current understanding of oceanic ecosystems, i.e., oligotrophic regions are characterized by low biomass and dominance of picoplankton, whereas eutrophic regions have high biomass to which nanoplankton and microplankton contribute relatively larger fractions. Global climatological, spatially integrated phytoplankton carbon biomass standing stock estimates using our PSD-based approach yield ˜ 0.25 Gt of C, consistent with analogous estimates from two other ocean color algorithms and several state-of-the-art Earth system models. Satisfactory in situ closure observed between PSD and POC measurements lends support to the theoretical basis of the PSD-based algorithm. Uncertainty budget analyses indicate that absolute carbon concentration uncertainties are driven by the PSD parameter No which determines particle number concentration to first order, while uncertainties in PFTs' fractional contributions to total C biomass

  14. The Correlation Between Atmospheric Dust Deposition to the Surface Ocean and SeaWiFS Ocean Color: A Global Satellite-Based Analysis

    NASA Technical Reports Server (NTRS)

    Erickson, D. J., III; Hernandez, J.; Ginoux, P.; Gregg, W.; Kawa, R.; Behrenfeld, M.; Esaias, W.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Since the atmospheric deposition of iron has been linked to primary productivity in various oceanic regions, we have conducted an objective study of the correlation of dust deposition and satellite remotely sensed surface ocean chlorophyll concentrations. We present a global analysis of the correlation between atmospheric dust deposition derived from a satellite-based 3-D atmospheric transport model and SeaWiFs estimates of ocean color. We use the monthly mean dust deposition fields of Ginoux et al. which are based on a global model of dust generation and transport. This model is driven by atmospheric circulation from the Data Assimilation Office (DAO) for the period 1995-1998. This global dust model is constrained by several satellite estimates of standard circulation characteristics. We then perform an analysis of the correlation between the dust deposition and the 1998 SeaWIFS ocean color data for each 2.0 deg x 2.5 deg lat/long grid point, for each month of the year. The results are surprisingly robust. The region between 40 S and 60 S has correlation coefficients from 0.6 to 0.95, statistically significant at the 0.05 level. There are swaths of high correlation at the edges of some major ocean current systems. We interpret these correlations as reflecting areas that have shear related turbulence bringing nitrogen and phosphorus from depth into the surface ocean, and the atmospheric supply of iron provides the limiting nutrient and the correlation between iron deposition and surface ocean chlorophyll is high. There is a region in the western North Pacific with high correlation, reflecting the input of Asian dust to that region. The southern hemisphere has an average correlation coefficient of 0.72 compared that in the northern hemisphere of 0.42 consistent with present conceptual models of where atmospheric iron deposition may play a role in surface ocean biogeochemical cycles. The spatial structure of the correlation fields will be discussed within the context

  15. Biogeographic patterns in ocean microbes emerge in a neutral agent-based model.

    PubMed

    Hellweger, Ferdi L; van Sebille, Erik; Fredrick, Neil D

    2014-09-12

    A key question in ecology and evolution is the relative role of natural selection and neutral evolution in producing biogeographic patterns. We quantify the role of neutral processes by simulating division, mutation, and death of 100,000 individual marine bacteria cells with full 1 million-base-pair genomes in a global surface ocean circulation model. The model is run for up to 100,000 years and output is analyzed using BLAST (Basic Local Alignment Search Tool) alignment and metagenomics fragment recruitment. Simulations show the production and maintenance of biogeographic patterns, characterized by distinct provinces subject to mixing and periodic takeovers by neighbors (coalescence), after which neutral evolution reestablishes the province and the patterns reorganize. The emergent patterns are substantial (e.g., down to 99.5% DNA identity between North and Central Pacific provinces) and suggest that microbes evolve faster than ocean currents can disperse them. This approach can also be used to explore environmental selection. PMID:25214628

  16. Functional Dorsoventral Symmetry in Relation to Lift-Based Swimming in the Ocean Sunfish Mola mola

    PubMed Central

    Watanabe, Yuuki; Sato, Katsufumi

    2008-01-01

    The largest (up to 2 tons) and a globally distributed teleost—the ocean sunfish Mola mola—is commonly regarded as a planktonic fish because of its unusual shape including absence of caudal fin. This common view was recently questioned because the horizontal movements of the ocean sunfish tracked by acoustic telemetry were independent of ocean currents. However, direct information regarding their locomotor performance under natural conditions is still lacking. By using multi-sensor tags, we show that sunfish indeed swam continuously with frequent vertical movements at speeds of 0.4–0.7 m s–1, which is similar to the records of other large fishes such as salmons, marlins, and pelagic sharks. The acceleration data revealed that they stroked their dorsal and anal fins synchronously (dominant frequency, 0.3–0.6 Hz) to generate a lift-based thrust, as penguins do using two symmetrical flippers. Morphological studies of sunfish (mass, 2–959 kg) showed that the dorsal and anal fins had similar external (symmetrical shape and identical area) and internal (identical locomotory muscle mass) features; however, the muscle shape differed markedly. We conclude that ocean sunfish have functional dorsoventral symmetry with regards to the non-homologous dorsal and anal fins that act as a pair of vertical hydrofoils. Although sunfish lack a swimbladder, we found that they are neutrally buoyant independent of depth because of their subcutaneous gelatinous tissue that has low density and is incompressible. Efficient lift-based swimming in conjunction with neutral buoyancy enables sunfish to travel long distances both horizontally and vertically. PMID:18941510

  17. Chlorophyll a algorithms for oligotrophic oceans: A novel approach based on three-band reflectance difference

    NASA Astrophysics Data System (ADS)

    Hu, Chuanmin; Lee, Zhongping; Franz, Bryan

    2012-01-01

    A new empirical algorithm is proposed to estimate surface chlorophyll a (Chl) concentrations in the global ocean for Chl ≤ 0.25 mg m-3(˜78% of the global ocean area). The algorithm is based on a color index (CI), defined as the difference between remote-sensing reflectance (Rrs, sr-1) in the green and a reference formed linearly between Rrsin the blue and red. For low-Chl waters, in situ data showed a tighter (and therefore better) relationship between CI and Chl than between traditional band ratios and Chl, which was further validated using global data collected concurrently by ship-borne and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua instruments. Model simulations showed that for low-Chl waters, compared with the band-ratio algorithm, the CI-based algorithm (CIA) was more tolerant to changes in chlorophyll-specific backscattering coefficient and performed similarly for different relative contributions of nonphytoplankton absorption. Simulations using existing atmospheric correction approaches further demonstrated that the CIA was much less sensitive than band-ratio algorithms to various errors induced by instrument noise and imperfect atmospheric correction (including sun glint and whitecap corrections). Image and time series analyses of SeaWiFS and MODIS/Aqua data also showed improved performance in terms of reduced image noise, more coherent spatial and temporal patterns, and better consistency between the two sensors. The reduction in noise and other errors is particularly useful to improve the detection of various ocean features such as eddies. Preliminary tests over Medium-Resolution Imaging Spectrometer and Coastal Zone Color Scanner data indicate that the new approach should be generally applicable to all past, current, and future ocean color instruments.

  18. Three-dimensional ocean sensor networks: A survey

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Liu, Yingjian; Guo, Zhongwen

    2012-12-01

    The past decade has seen a growing interest in ocean sensor networks because of their wide applications in marine research, oceanography, ocean monitoring, offshore exploration, and defense or homeland security. Ocean sensor networks are generally formed with various ocean sensors, autonomous underwater vehicles, surface stations, and research vessels. To make ocean sensor network applications viable, efficient communication among all devices and components is crucial. Due to the unique characteristics of underwater acoustic channels and the complex deployment environment in three dimensional (3D) ocean spaces, new efficient and reliable communication and networking protocols are needed in design of ocean sensor networks. In this paper, we aim to provide an overview of the most recent advances in network design principles for 3D ocean sensor networks, with focuses on deployment, localization, topology design, and position-based routing in 3D ocean spaces.

  19. Hypercompetitive Environments: An Agent-based model approach

    NASA Astrophysics Data System (ADS)

    Dias, Manuel; Araújo, Tanya

    Information technology (IT) environments are characterized by complex changes and rapid evolution. Globalization and the spread of technological innovation have increased the need for new strategic information resources, both from individual firms and management environments. Improvements in multidisciplinary methods and, particularly, the availability of powerful computational tools, are giving researchers an increasing opportunity to investigate management environments in their true complex nature. The adoption of a complex systems approach allows for modeling business strategies from a bottom-up perspective — understood as resulting from repeated and local interaction of economic agents — without disregarding the consequences of the business strategies themselves to individual behavior of enterprises, emergence of interaction patterns between firms and management environments. Agent-based models are at the leading approach of this attempt.

  20. Data-based estimates of the ocean carbon sink variability - results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM)

    NASA Astrophysics Data System (ADS)

    Rödenbeck, Christian; Bakker, Dorothee; Gruber, Nicolas; Iida, Yosuke; Jacobson, Andy; Jones, Steve; Landschützer, Peter; Metzl, Nicolas; Nakaoka, Shin-ichiro; Olsen, Are; Park, Geun-Ha; Peylin, Philippe; Rodgers, Keith; Sasse, Tristan; Schuster, Ute; Shutler, James; Valsala, Vinu; Wanninkhof, Rik; Zeng, Jiye

    2016-04-01

    Using measurements of the surface-ocean COtwo partial pressure (pCOtwo) from the SOCAT and LDEO data bases and 14 different pCOtwo mapping methods recently collated by the Surface Ocean pCOtwo Mapping intercomparison (SOCOM) initiative, variations in regional and global sea-air COtwo fluxes are investigated. Though the available mapping methods use widely different approaches, we find relatively consistent estimates of regional pCOtwo seasonality, in line with previous estimates. In terms of interannual variability (IAV), all mapping methods estimate the largest variations to occur in the Eastern equatorial Pacific. Despite considerable spread in the detailed variations, mapping methods that fit the data more closely also tend to agree more closely with each other in regional averages. Encouragingly, this includes mapping methods belonging to complementary types - taking variability either directly from the pCOtwo data or indirectly from driver data via regression. From a weighted ensemble average, we find an IAV amplitude of the global sea-air COtwo flux of IAVampl (standard deviation over AnalysisPeriod), which is larger than simulated by biogeochemical process models. On a decadal perspective, the global ocean COtwo uptake is estimated to have gradually increased since about 2000, with little decadal change prior to that. The weighted mean net global ocean COtwo sink estimated by the SOCOM ensemble is -1.75 UPgCyr (AnalysisPeriod), consistent within uncertainties with estimates from ocean-interior carbon data or atmospheric oxygen trends. Using data-based sea-air COtwo fluxes in atmospheric COtwo inversions also helps to better constrain land-atmosphere COtwo fluxes.

  1. Mooring-based long-term observation of oceanographic condition in the Chukchi Ses and Canada Basin of the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Kikuchi, Takashi; Itoh, Motoyo; Nishino, Shigeto; Watanabe, Eiji

    2015-04-01

    Changes of the Arctic Ocean environment are well known as one of the most remarkable evidences of global warming, attracting social and public attentions as well as scientists'. However, to illustrate on-going changes and predict future condition of the Arctic marine environment, we still do not have enough knowledge of Arctic sea ice and marine environment. In particular, lack of observation data in winter, e.g., under sea ice, still remains a key issue for precise understanding of seasonal cycle on oceanographic condition in the Arctic Ocean. Mooring-based observation is one of the most useful methods to collect year-long data in the Arctic Ocean. We have been conducting long-term monitoring using mooring system in the Pacific sector of the Arctic Ocean. Volume, heat, and freshwater fluxes through Barrow Canyon where is a major conduit of Pacific-origin water-masses into the Canada Basin have been observed since 2000. We show from an analysis of the mooring results that volume flux through Barrow Canyon was about 60 % of Bering Strait volume flux. Averaged heat flux ranges from 0.9 to 3.07 TW, which could melt 88,000 to 300,000 km2 of 1m thick ice in the Canada Basin, which likely contributed to sea ice retreat in the Pacific sector of the Arctic Ocean. In winter, we found inter-annual variability in salinity related to coastal polynya activity in the Chukchi Sea. In collaboration with Distributed Biological Observatory (DBO) project, which is one of the tasks of Sustaining Arctic Observing Network (SAON), we also initiated year-long mooring observation in the Hope Valley of the southern Chukchi Sea since 2012. Interestingly, winter oceanographic conditions in the Hope Valley are greatly different between in 2012-2013 and in 2013-2014. We speculate that differences of sea ice freeze-up and coastal polynya activity in the southern Chukchi Sea cause significant difference of winter oceanographic condition. It suggests that recent sea ice reduction in the Pacific

  2. Desktop Publishing in a PC-Based Environment.

    ERIC Educational Resources Information Center

    Sims, Harold A.

    1987-01-01

    Identifies, considers, and interrelates the functionality of hardware, firmware, and software types; discusses the relationship of input and output devices in the PC-based desktop publishing environment; and reports some of what has been experienced in three years of working intensively in/with desktop publishing devices and solutions. (MES)

  3. Advances in Web-Based Education: Personalized Learning Environments

    ERIC Educational Resources Information Center

    Magoulas, George, Ed.; Chen, Sherry, Ed.

    2006-01-01

    Advances in technology are increasingly impacting the way in which curriculum is delivered and assessed. The emergence of the Internet has offered learners a new instructional delivery system that connects them with educational resources. "Advances in Web-Based Education: Personalized Learning Environments" covers a wide range of factors that…

  4. A Case-Based Pharmacy Environment: Cognitive Flexibility + Social Constructivism.

    ERIC Educational Resources Information Center

    Oliver, Kevin M.

    The Internet Web Site on Virtual Clinical Applications and Disease Management is a hypermedia, case-based open learning environment that was designed to promote cognitive flexibility in college students at The University of Georgia College of Pharmacy. With a key objective of pharmacy education being patient problem-solving skills, this…

  5. Instructionist versus Constructionist Web-Based Collaborative Learning Environments.

    ERIC Educational Resources Information Center

    Sherman, Greg

    This study investigated the effects of instructionist (navigational, functional) versus constructionist (adaptive) World Wide Web (WWW) site environments on collaboration, achievement, attitudes, and perceived level of learner controls reported by students after working in cooperative dyads within the different types of Web-based learning…

  6. Scaffolding Diagnostic Reasoning in Case-Based Learning Environments.

    ERIC Educational Resources Information Center

    Jonassen, David H.

    1996-01-01

    Computer-delivered, case-based instruction can provide medical students with valuable clinical diagnostic experiences before encountering real patients. Diagnosis requires physicians to understand and use causal reasoning for prediction. Such reasoning may be scaffolded in the design of computerized learning environments. Scaffolding of causal…

  7. Designing a Virtual-Reality-Based, Gamelike Math Learning Environment

    ERIC Educational Resources Information Center

    Xu, Xinhao; Ke, Fengfeng

    2016-01-01

    This exploratory study examined the design issues related to a virtual-reality-based, gamelike learning environment (VRGLE) developed via OpenSimulator, an open-source virtual reality server. The researchers collected qualitative data to examine the VRGLE's usability, playability, and content integration for math learning. They found it important…

  8. Narrative-Based Interactive Learning Environments from Modelling Reasoning

    ERIC Educational Resources Information Center

    Yearwood, John; Stranieri, Andrew

    2007-01-01

    Narrative and story telling has a long history of use in structuring, organising and communicating human experience. This paper describes a narrative based interactive intelligent learning environment which aims to elucidate practical reasoning using interactive emergent narratives that can be used in training novices in decision making. Its…

  9. Measuring Self-Regulation in Computer-Based Learning Environments

    ERIC Educational Resources Information Center

    Schraw, Gregory

    2010-01-01

    I provide a summary of the four invited articles in this special issue and compare and contrast different methods for measuring self-regulation in computer-based learning environments (CBLEs). I present a taxonomy that distinguishes between offline and online measures and further distinguishes subcategories within each of these categories. I…

  10. A Software Laboratory Environment for Computer-Based Problem Solving.

    ERIC Educational Resources Information Center

    Kurtz, Barry L.; O'Neal, Micheal B.

    This paper describes a National Science Foundation-sponsored project at Louisiana Technological University to develop computer-based laboratories for "hands-on" introductions to major topics of computer science. The underlying strategy is to develop structured laboratory environments that present abstract concepts through the use of computer…

  11. Study concerning the utilization of the ocean spreading center environment for the conversion of biomass to a liquid fuel. (Includes Appendix A: hydrothermal petroleum genesis). [Supercritical water

    SciTech Connect

    Steverson, M.; Stormberg, G.

    1985-01-01

    This document contains a report on the feasibility of utilizing energy obtained from ocean spreading centers as process heat for the conversion of municipal solid wastes to liquid fuels. The appendix contains a paper describing hydrothermal petroleum genesis. Both have been indexed separately for inclusion in the Energy Data Base. (DMC)

  12. An approach to accidents modeling based on compounds road environments.

    PubMed

    Fernandes, Ana; Neves, Jose

    2013-04-01

    The most common approach to study the influence of certain road features on accidents has been the consideration of uniform road segments characterized by a unique feature. However, when an accident is related to the road infrastructure, its cause is usually not a single characteristic but rather a complex combination of several characteristics. The main objective of this paper is to describe a methodology developed in order to consider the road as a complete environment by using compound road environments, overcoming the limitations inherented in considering only uniform road segments. The methodology consists of: dividing a sample of roads into segments; grouping them into quite homogeneous road environments using cluster analysis; and identifying the influence of skid resistance and texture depth on road accidents in each environment by using generalized linear models. The application of this methodology is demonstrated for eight roads. Based on real data from accidents and road characteristics, three compound road environments were established where the pavement surface properties significantly influence the occurrence of accidents. Results have showed clearly that road environments where braking maneuvers are more common or those with small radii of curvature and high speeds require higher skid resistance and texture depth as an important contribution to the accident prevention. PMID:23376544

  13. Diatom Phytochromes Reveal the Existence of Far-Red-Light-Based Sensing in the Ocean.

    PubMed

    Fortunato, Antonio Emidio; Jaubert, Marianne; Enomoto, Gen; Bouly, Jean-Pierre; Raniello, Raffaella; Thaler, Michael; Malviya, Shruti; Bernardes, Juliana Silva; Rappaport, Fabrice; Gentili, Bernard; Huysman, Marie J J; Carbone, Alessandra; Bowler, Chris; d'Alcalà, Maurizio Ribera; Ikeuchi, Masahiko; Falciatore, Angela

    2016-03-01

    The absorption of visible light in aquatic environments has led to the common assumption that aquatic organisms sense and adapt to penetrative blue/green light wavelengths but show little or no response to the more attenuated red/far-red wavelengths. Here, we show that two marine diatom species, Phaeodactylum tricornutum and Thalassiosira pseudonana, possess a bona fide red/far-red light sensing phytochrome (DPH) that uses biliverdin as a chromophore and displays accentuated red-shifted absorbance peaks compared with other characterized plant and algal phytochromes. Exposure to both red and far-red light causes changes in gene expression in P. tricornutum, and the responses to far-red light disappear in DPH knockout cells, demonstrating that P. tricornutum DPH mediates far-red light signaling. The identification of DPH genes in diverse diatom species widely distributed along the water column further emphasizes the ecological significance of far-red light sensing, raising questions about the sources of far-red light. Our analyses indicate that, although far-red wavelengths from sunlight are only detectable at the ocean surface, chlorophyll fluorescence and Raman scattering can generate red/far-red photons in deeper layers. This study opens up novel perspectives on phytochrome-mediated far-red light signaling in the ocean and on the light sensing and adaptive capabilities of marine phototrophs. PMID:26941092

  14. Forecasting front displacements with a satellite based ocean forecasting (SOFT) system

    NASA Astrophysics Data System (ADS)

    Alvarez, A.; Orfila, A.; Basterretxea, G.; Tintoré, J.; Vizoso, G.; Fornes, A.

    2007-03-01

    Relatively long term time series of satellite data are nowadays available. These spatio-temporal time series of satellite observations can be employed to build empirical models, called satellite based ocean forecasting (SOFT) systems, to forecast certain aspects of future ocean states. The forecast skill of SOFT systems predicting the sea surface temperature (SST) at sub-basin spatial scale (from hundreds to thousand kilometres), has been extensively explored in previous works. Thus, these works were mostly focussed on predicting large scale patterns spatially stationary. At spatial scales smaller than sub-basin (from tens to hundred kilometres), spatio-temporal variability is more complex and propagating structures are frequently present. In this case, traditional SOFT systems based on Empirical Orthogonal Function (EOF) decompositions could not be optimal prediction systems. Instead, SOFT systems based on Complex Empirical Orthogonal Functions (CEOFs) are, a priori, better candidates to resolve these cases. In this work we study and compare the performance of an EOF and CEOF based SOFT systems forecasting the SST at weekly time scales of a propagating mesoscale structure. The SOFT system was implemented in an area of the Northern Balearic Sea (Western Mediterranean Sea) where a moving frontal structure is recurrently observed. Predictions from both SOFT systems are compared with observations and with the predictions obtained from persistence models. Results indicate that the implemented SOFT systems are superior in terms of predictability to persistence. No substantial differences have been found between the EOF and CEOF-SOFT systems.

  15. NLS cycle 1 and NLS 2 base heating technical notes. Appendix 3: Preliminary cycle 1 NLS base heating environments. Cycle 1 NLS base heating environments. NLS 2 650K STME base heating environments

    NASA Technical Reports Server (NTRS)

    Bender, Robert L.; Reardon, John E.; Prendergast, Maurice J.; Schmitz, Craig P.; Brown, John R.

    1992-01-01

    A preliminary analysis of National Launch System ascent plume induced base heating environments has been completed to support the Induced Environments Panel's objective to assist in maturing the NLS vehicle (1.5 stage and heavy launch lift vehicle) design. Environments during ascent have been determined from this analysis for a few selected locations on the engine nozzles and base heat shield for both vehicles. The environments reflect early summer 1991 configurations and performance data and conservative methodology. A more complete and thorough analysis is under way to update these environments for the cycle 1 review in January 1992.

  16. WAVE: Interactive Wave-based Sound Propagation for Virtual Environments.

    PubMed

    Mehra, Ravish; Rungta, Atul; Golas, Abhinav; Ming Lin; Manocha, Dinesh

    2015-04-01

    We present an interactive wave-based sound propagation system that generates accurate, realistic sound in virtual environments for dynamic (moving) sources and listeners. We propose a novel algorithm to accurately solve the wave equation for dynamic sources and listeners using a combination of precomputation techniques and GPU-based runtime evaluation. Our system can handle large environments typically used in VR applications, compute spatial sound corresponding to listener's motion (including head tracking) and handle both omnidirectional and directional sources, all at interactive rates. As compared to prior wave-based techniques applied to large scenes with moving sources, we observe significant improvement in runtime memory. The overall sound-propagation and rendering system has been integrated with the Half-Life 2 game engine, Oculus-Rift head-mounted display, and the Xbox game controller to enable users to experience high-quality acoustic effects (e.g., amplification, diffraction low-passing, high-order scattering) and spatial audio, based on their interactions in the VR application. We provide the results of preliminary user evaluations, conducted to study the impact of wave-based acoustic effects and spatial audio on users' navigation performance in virtual environments. PMID:26357093

  17. Biomass of zooplankton in the eastern Arctic Ocean - A base line study

    NASA Astrophysics Data System (ADS)

    Kosobokova, Ksenia; Hirche, Hans-Jürgen

    2009-09-01

    Only a few historical assessments of the zooplankton biomass in the Arctic Ocean exist are difficult to compare due to methodological differences including incomplete sampling of the water column. We present assessments of the zooplankton biomass for 66 locations scattered over the Eurasian and Makarov Basins of the Arctic Ocean and analyze regional variability and factors affecting the biomass distribution. The study is based on material from several summer expeditions of RV Polarstern (1993-1998) that was collected and processed using consistent methods, i.e. stratified sampling of the entire water column from the bottom to the surface with very similar gear and standardized calculation of biomass. Total zooplankton biomass varied strongly from 1.9 to 23.9 g DW m -2 dry mass. Regional variability was mainly related to the circulation pattern, but local food availability was also important. A belt of elevated biomass along the Eurasian continental margin was associated with the advection of Atlantic pelagic populations within the Arctic Ocean Boundary Current along the Siberian shelves and returning branches along mid-ocean ridges. Biomass was highest in the core of the Atlantic inflow and remained rather stable along the continental margins, but species composition changed, pointing to different adaptation levels to local conditions by advected species. Biomass gradually decreased towards the shelves and basins and was lowest in the centers of the basins north of 85°N. In the slope region, three Calanus species ( C. hyperboreus, C. glacialis, C. finmarchicus) and Metridia longa contributed most to the biomass, chaetognaths ( Eukrohnia hamata) were also important. In the basins, C. hyperboreus was dominant, copepods made up to 97% of total biomass. Vertical distribution was similar at all stations with biomass maxima in the upper 50 m layer except for stations near Fram Strait and northern Kara Sea, the gateways of Atlantic water to the Arctic Ocean, where maxima

  18. An HLA based design of space system simulation environment

    NASA Astrophysics Data System (ADS)

    Li, Yinghua; Li, Yong; Liu, Jie

    2007-06-01

    Space system simulation is involved in many application fields, such as space remote sensing and space communication, etc. A simulation environment which can be shared by different space system simulation is needed. Two rules, called object template towing and hierarchical reusability, are proposed. Based on these two rules, the architecture, the network structure and the function structure of the simulation environment are designed. Then, the mechanism of utilizing data resources, inheriting object models and running simulation systems are also constructed. These mechanisms make the simulation objects defined in advance be easily inherited by different HLA federates, the fundamental simulation models be shared by different simulation systems. Therefore, the simulation environment is highly universal and reusable.

  19. Development of Web-based Virtual Training Environment for Machining

    NASA Astrophysics Data System (ADS)

    Yang, Zhixin; Wong, S. F.

    2010-05-01

    With the booming in the manufacturing sector of shoe, garments and toy, etc. in pearl region, training the usage of various facilities and design the facility layout become crucial for the success of industry companies. There is evidence that the use of virtual training may provide benefits in improving the effect of learning and reducing risk in the physical work environment. This paper proposed an advanced web-based training environment that could demonstrate the usage of a CNC machine in terms of working condition and parameters selection. The developed virtual environment could provide training at junior level and advanced level. Junior level training is to explain machining knowledge including safety factors, machine parameters (ex. material, speed, feed rate). Advanced level training enables interactive programming of NG coding and effect simulation. Operation sequence was used to assist the user to choose the appropriate machining condition. Several case studies were also carried out with animation of milling and turning operations.

  20. Considering Affective Responses towards Environments for Enhancing Location Based Services

    NASA Astrophysics Data System (ADS)

    Huang, H.; Gartner, G.; Klettner, S.; Schmidt, M.

    2014-04-01

    A number of studies in the field of environmental psychology show that humans perceive and evaluate their surroundings affectively. Some places are experienced as unsafe, while some others as attractive and interesting. Experiences from daily life show that many of our daily behaviours and decision-making are often influenced by this kind of affective responses towards environments. Location based services (LBS) are often designed to assist and support people's behaviours and decision-making in space. In order to provide services with high usefulness (usability and utility), LBS should consider these kinds of affective responses towards environments. This paper reports on the results of a research project, which studies how people's affective responses towards environments can be modelled and acquired, as well as how LBS can benefit by considering these affective responses. As one of the most popular LBS applications, mobile pedestrian navigation systems are used as an example for illustration.

  1. The Story of the Oceans and Salt. What We Take from Our Environment. Science and Technology Education in Philippine Society.

    ERIC Educational Resources Information Center

    Philippines Univ., Quezon City. Science Education Center.

    This module provides information on: (1) the origin of the oceans; (2) sources of minerals and salt found in the sea; and (3) the role and uses of salt in various cultures (stating, for example, that the expression "salt of the earth" describes a person who is considered one of the best). (JN)

  2. Investigating Effects of Problem-Based versus Lecture-Based Learning Environments on Student Motivation

    ERIC Educational Resources Information Center

    Wijnia, Lisette; Loyens, Sofie M. M.; Derous, Eva

    2011-01-01

    This study examines the effects of two learning environments (i.e., problem-based learning [PBL] versus lecture-based [LB] environments) on undergraduates' study motivation. Survey results demonstrated that PBL students scored higher on competence but did not differ from LB students on autonomous motivation. Analyses of focus groups further…

  3. High-frequency Earth rotation variations deduced from altimetry-based ocean tides

    NASA Astrophysics Data System (ADS)

    Madzak, Matthias; Schindelegger, Michael; Böhm, Johannes; Bosch, Wolfgang; Hagedoorn, Jan

    2016-06-01

    A model of diurnal and semi-diurnal variations in Earth rotation parameters (ERP) is constructed based on altimetry-measured tidal heights from a multi-mission empirical ocean tide solution. Barotropic currents contributing to relative angular momentum changes are estimated for nine major tides in a global inversion algorithm that solves the two-dimensional momentum equations on a regular 0.5° grid with a heavily weighted continuity constraint. The influence of 19 minor tides is accounted for by linear admittance interpolation of ocean tidal angular momentum, although the assumption of smooth admittance variations with frequency appears to be a doubtful concept for semi-diurnal mass terms in particular. A validation of the newly derived model based on post-fit corrections to polar motion and universal time (Δ UT1) from the analysis of Very Long Baseline Interferometry (VLBI) observations shows a variance reduction for semi-diurnal Δ UT1 residuals that is significant at the 0.05 level with respect to the conventional ERP model. Improvements are also evident for the explicitly modeled K_1 , Q_1 , and K_2 tides in individual ERP components, but large residuals of more than 15 μ as remain at the principal lunar frequencies of O_1 and M_2 . We attribute these shortcomings to uncertainties in the inverted relative angular momentum changes and, to a minor extent, to violation of mass conservation in the empirical ocean tide solution. Further dedicated hydrodynamic modeling efforts of these anomalous constituents are required to meet the accuracy standards of modern space geodesy.

  4. Ship-based remote sensing observations of clouds and aerosol over the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Pospichal, Bernhard; Wolf, Veronika; Pietsch, Alexandra; Engelmann, Ronny; Macke, Andreas

    2014-05-01

    Within the framework of the OCEANET project, ship-based remote sensing observations of the atmosphere above the Atlantic Ocean have been performed on board of the German research vessels Polarstern and Meteor. Since 2007, twelve cruises took place, mostly between Bremerhaven (Germany) and Cape Town (South Africa) or Punta Arenas (Chile), respectively. In 2014 and 2015, two additional cruises will be performed. The goal of these ship-based measurements is a better understanding of water vapor, cloud and aerosol interaction over the open sea where data are scarce. The project was designed to measure the full atmospheric energy budget in different climate zones, including exchange processes at the sea surface. The main instrumentation on all cruises consisted of a passive microwave radiometer, a full sky imager, sun photometer, lidar ceilometer and broadband solar and infrared radiation measurements. In addition a multi wavelength Raman lidar (PollyXT) was on board of six cruises. Spectral solar radiance and irradiance observations have been performed on four cruises. With this dataset, a variety of topics can be addressed. This presentation will focus on marine stratocumulus clouds which are widespread over oceans and still pose a large uncertainty for determining the Earth's energy budget. Detailed studies for the northern trade wind zone off the West African coast will be presented. The emphasis lies on stratocumulus cloud properties, such as frequency, size, variability, liquid water content as well as their impact on surface radiation. Additionally, the influence of Saharan dust on the cloud occurrence will be addressed. Dust outbreaks over the ship could be observed in several years, including also at a cruise from the Caribbean Sea to Cape Verde in 2013. Furthermore, we will give a statistical overview of the meridional distribution of atmospheric water vapour and clouds over the Atlantic Ocean. With six years of measurements, always at the same time of the

  5. Microflown based sound pressure microphone suitable for harsh environments

    NASA Astrophysics Data System (ADS)

    Yntema, D. R.; de Bree, Hans-Elias

    2005-09-01

    There are several cases where a sound field reconstruction or prediction is required under harsh conditions such as high temperature, humidity or chemical attack. A regular pressure microphone will not last long under these conditions. Electret based pressure microphones stop working well above 70 degrees centigrade and other type of pressure microphones often operate with a built in amplifier that does not function above 120 degrees centigrade. The functionality of a MEMS based Microflown acoustic particle velocity sensor in air lies in the use of two heated platinum wires that are resistant to high temperatures and chemical attack. The wires are supported by silicon that has no other function than provide support. A pressure microphone is made based upon the Microflown principle by putting it in the opening of an enclosure. In this paper a silicon and platinum based sound probe for harsh environments is created, combining particle velocity and pressure measurements in a harsh environment. Use of this sensor is possible up to 250 degrees centigrade, in humid and under most chemical environments. The probe realization as well as calibration measurements are presented.

  6. A highly redox-heterogeneous ocean in South China during the early Cambrian (˜529-514 Ma): Implications for biota-environment co-evolution

    NASA Astrophysics Data System (ADS)

    Jin, Chengsheng; Li, Chao; Algeo, Thomas J.; Planavsky, Noah J.; Cui, Hao; Yang, Xinglian; Zhao, Yuanlong; Zhang, Xingliang; Xie, Shucheng

    2016-05-01

    The "Cambrian Explosion" is known for rapid increases in the morphological disparity and taxonomic diversity of metazoans. It has been widely proposed that this biological event was a consequence of oxygenation of the global ocean, but this hypothesis is still under debate. Here, we present high-resolution Fe-S-C-Al-trace element geochemical records from the Jinsha (outer shelf) and Weng'an (outer shelf) sections of the early Cambrian Yangtze Platform, integrating these results with previously published data from six correlative sections representing a range of water depths (Xiaotan, Shatan, Dingtai, Yangjiaping, Songtao, and Longbizui). The integrated iron chemistry and redox-sensitive trace element data suggest that euxinic mid-depth waters dynamically coexisted with oxic surface waters and ferruginous deep waters during the earliest Cambrian, but that stepwise expansion of oxic waters commenced during Cambrian Stage 3 (∼ 521- 514 Ma). Combined with data from lower Cambrian sections elsewhere, including Oman, Iran and Canada, we infer that the global ocean exhibited a high degree of redox heterogeneity during the early Cambrian, consistent with low atmospheric oxygen levels (∼ 10- 40% of present atmospheric level, or PAL). A large spatial gradient in pyrite sulfur isotopic compositions (δ34Spy), which vary from a mean of - 12.0 ‰ in nearshore areas to + 22.5 ‰ in distal deepwater sections in lower Cambrian marine units of South China imply low concentrations and spatial heterogeneity of seawater sulfate, which is consistent with a limited oceanic sulfate reservoir globally. By comparing our reconstructed redox chemistry with fossil records from the lower Cambrian of South China, we infer that a stepwise oxygenation of shelf and slope environments occurred concurrently with a gradual increase in ecosystem complexity. However, deep waters remained anoxic and ferruginous even as macrozooplankton and suspension-feeding mesozooplankton appeared during

  7. A highly redox-heterogeneous ocean in South China during the early Cambrian (˜529-514 Ma): Implications for biota-environment co-evolution

    NASA Astrophysics Data System (ADS)

    Jin, Chengsheng; Li, Chao; Algeo, Thomas J.; Planavsky, Noah J.; Cui, Hao; Yang, Xinglian; Zhao, Yuanlong; Zhang, Xingliang; Xie, Shucheng

    2016-05-01

    The "Cambrian Explosion" is known for rapid increases in the morphological disparity and taxonomic diversity of metazoans. It has been widely proposed that this biological event was a consequence of oxygenation of the global ocean, but this hypothesis is still under debate. Here, we present high-resolution Fe-S-C-Al-trace element geochemical records from the Jinsha (outer shelf) and Weng'an (outer shelf) sections of the early Cambrian Yangtze Platform, integrating these results with previously published data from six correlative sections representing a range of water depths (Xiaotan, Shatan, Dingtai, Yangjiaping, Songtao, and Longbizui). The integrated iron chemistry and redox-sensitive trace element data suggest that euxinic mid-depth waters dynamically coexisted with oxic surface waters and ferruginous deep waters during the earliest Cambrian, but that stepwise expansion of oxic waters commenced during Cambrian Stage 3 (˜ 521- 514 Ma). Combined with data from lower Cambrian sections elsewhere, including Oman, Iran and Canada, we infer that the global ocean exhibited a high degree of redox heterogeneity during the early Cambrian, consistent with low atmospheric oxygen levels (˜ 10- 40% of present atmospheric level, or PAL). A large spatial gradient in pyrite sulfur isotopic compositions (δ34Spy), which vary from a mean of - 12.0 ‰ in nearshore areas to + 22.5 ‰ in distal deepwater sections in lower Cambrian marine units of South China imply low concentrations and spatial heterogeneity of seawater sulfate, which is consistent with a limited oceanic sulfate reservoir globally. By comparing our reconstructed redox chemistry with fossil records from the lower Cambrian of South China, we infer that a stepwise oxygenation of shelf and slope environments occurred concurrently with a gradual increase in ecosystem complexity. However, deep waters remained anoxic and ferruginous even as macrozooplankton and suspension-feeding mesozooplankton appeared during Cambrian

  8. Planet Ocean

    NASA Astrophysics Data System (ADS)

    Afonso, Isabel

    2014-05-01

    A more adequate name for Planet Earth could be Planet Ocean, seeing that ocean water covers more than seventy percent of the planet's surface and plays a fundamental role in the survival of almost all living species. Actually, oceans are aqueous solutions of extraordinary importance due to its direct implications in the current living conditions of our planet and its potential role on the continuity of life as well, as long as we know how to respect the limits of its immense but finite capacities. We may therefore state that natural aqueous solutions are excellent contexts for the approach and further understanding of many important chemical concepts, whether they be of chemical equilibrium, acid-base reactions, solubility and oxidation-reduction reactions. The topic of the 2014 edition of GIFT ('Our Changing Planet') will explore some of the recent complex changes of our environment, subjects that have been lately included in Chemistry teaching programs. This is particularly relevant on high school programs, with themes such as 'Earth Atmosphere: radiation, matter and structure', 'From Atmosphere to the Ocean: solutions on Earth and to Earth', 'Spring Waters and Public Water Supply: Water acidity and alkalinity'. These are the subjects that I want to develop on my school project with my pupils. Geographically, our school is located near the sea in a region where a stream flows into the sea. Besides that, our school water comes from a borehole which shows that the quality of the water we use is of significant importance. This project will establish and implement several procedures that, supported by physical and chemical analysis, will monitor the quality of water - not only the water used in our school, but also the surrounding waters (stream and beach water). The samples will be collected in the borehole of the school, in the stream near the school and in the beach of Carcavelos. Several physical-chemical characteristics related to the quality of the water will

  9. A first estimation of SMOS-based ocean surface T-S diagrams

    NASA Astrophysics Data System (ADS)

    Sabia, Roberto; Klockmann, Marlene; Fernández-Prieto, Diego; Donlon, Craig

    2014-10-01

    A first estimation of satellite-based ocean surface T-S diagrams is performed by using SMOS Sea Surface Salinity (SSS) and OSTIA Sea Surface Temperature (SST) and comparing them with in situ measurements interpolated fields obtained by the Argo-buoys for the North Atlantic and over the entire year 2011. The key objectives at the base of this study are: (1) To demonstrate the feasibility of generating routinely satellite-derived surface T-S diagrams, obviating the lack of extensive sampling of the surface open ocean, (2) To display the T-S diagrams variability and the distribution/dynamics of SSS, altogether with SST and the relative density with respect to in situ measurements, and (3) To assess the SMOS SSS data added value in detecting geophysical signals not sensed/resolved by the Argo measurements. To perform the latter analysis, the satellite-Argo mismatches have been overlapped with geophysical parameters of precipitation rates, surface heat and freshwater fluxes and wind speed data. Ongoing and future efforts focus on enlarging the study area and the temporal frame of the analysis and aim at developing a method for the systematic identification of surface water masses formation areas by remotely sensed data.

  10. A Time Series of Sea Surface Nitrate and Nitrate based New Production in the Global Oceans

    NASA Astrophysics Data System (ADS)

    Goes, J. I.; Fargion, G. S.; Gomes, H. R.; Franz, B. A.

    2014-12-01

    With support from NASA's MEaSUREs program, we are developing algorithms for two innovative satellite-based Earth Science Data Records (ESDRs), one Sea Surface Nitrate (SSN) and the other, Nitrate based new Production (NnP). Newly developed algorithms will be applied to mature ESDRs of Chlorophyll a and SST available from NASA, to generate maps of SSN and NnP. Our proposed ESDRs offer the potential of greatly improving our understanding of the role of the oceans in global carbon cycling, earth system processes and climate change, especially for regions and seasons which are inaccessible to traditional shipboard studies. They also provide an innovative means for validating and improving coupled ecosystem models that currently rely on global maps of nitrate generated from multi-year data sets. To aid in our algorithm development efforts and to ensure that our ESDRs are truly global in nature, we are currently in the process of assembling a large database of nutrients from oceanographic institutions all over the world. Once our products are developed and our algorithms are fine-tuned, large-scale data production will be undertaken in collaboration with NASA's Ocean Biology Processing Group (OPBG), who will make the data publicly available first as evaluation products and then as mature ESDRs.