OCEANS 2009最新文献

{"title":"Bio-physical ocean modeling in the Gulf of Mexico","authors":"Sergio de Rada, R. Arnone, S. Anderson","doi":"10.23919/OCEANS.2009.5422217","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422217","url":null,"abstract":"The Naval Research Laboratory (NRL) Oceanography Division has implemented a 1/25º horizontal-resolution numerical ocean model for the Gulf of Mexico (GOM). The model domain encompasses the entire GOM extending from 18º to 31º North and from 77º to 98º West. The physical formulation is based on the Naval Coastal Ocean Model (NCOM) configured with a 40 level σ-z vertical structure: 19 terrain-following σ (sigma) levels at the top of the water column, and 21 z (depth) levels at the bottom. The terrain-following levels, reaching from the surface to about 137 meters, allow higher vertical resolutions for resolving mixed layer/shallow waters, while the z-levels are used in the stratified ocean. The ocean bathymetry is constructed from the NRL 2-minute database with the coastline set at a depth of 2 meters. The physical model is one-way coupled to a 13-component ecosystem (biogeochemical) model [Chai et. al., 2002, 2003, 2007] that includes nutrients, two classes of plankton, as well as O and CO2. The current configuration is tailored, but not limited to, real-time (RT) prediction; providing nowcasts (current state of the ocean) and up to 120-hour forecasts for the region. In this configuration, the model receives (initial) boundary information from the operational 1/8º Global NCOM, and it is forced by 3-hourly 1/2º momentum and heat fluxes from the Naval Operational Global Prediction System (NOGAPS). The NCOMGOM model assimilates daily surface/subsurface temperature and salinity generated by the Modular Ocean Data Assimilation System (MODAS), which regresses satellite derived Sea Surface Temperature (SST) and Sea Surface Height (SSH) data to obtain T&S synthetic profiles. The model was initialized on January 1, 2009 from the operational 1/8º Global NCOM physical state and from the World Ocean Atlas 2005 and Carbon Dioxide Information Analysis Center (CDIAC) biogeochemical fields. Results from the real-time NCOMGOM nowcasting/forecasting ocean modeling system are compared and evaluated against in-situ and remotely sensed observations, which include bio-optical products processed by the NRL Ocean Color Section. Google Earth/Ocean is used as a platform for viewing the model results interactively and dynamically in real-time. Initial assessment of the model prediction skill is presented along with future plans for improvements and enhancements. The suitability of the system as a tool for decision management is discussed, outlining processes localized to particular areas such as hypoxia, dead zones, wetland loss and degradation, harmful algal blooms, as well as tropical storms and related issues that affect all coastal regions of the Gulf of Mexico.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129254253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anti-Submarine Warfare visual analysis tool geospatially enabling Four Dimensional METOC data","authors":"Z. Rouse, J. B. Haynie, C. Davis","doi":"10.23919/oceans.2009.5422102","DOIUrl":"https://doi.org/10.23919/oceans.2009.5422102","url":null,"abstract":"This research proposes methods and develops an open source based prototype for enabling Four-Dimensional (4-D) METOC data in support of the Navy Anti-Submarine Warfare directorate's visual analysis requirements. Useful 4-D METOC data is currently produced and stored in netCDF format. The data is then used to create, for each depth and time, a static JPEG image that becomes available for dissemination to the fleet. Current Command and Control (C2) systems use Open Geospatial Consortium (OGC) compliant GIS maps to display the common operational picture (COP) but the large collection of JPEG images cannot be introduced as map layers on the COP to fused decision support.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129302948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multipath cancellation using a maximum likelihood metric space","authors":"J. Piper","doi":"10.23919/OCEANS.2009.5422474","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422474","url":null,"abstract":"Multipath signals occur in many sonar, radar, and communication applications. It is, of course, generally desirable to eliminate these unwanted signals. Traditional array signal processing techniques often have trouble eliminating these signals when only a small number of array elements are available. The maximum likelihood method explicitly models multiple signals in its mathematical construction. This feature effectively opens up a multidimensional space that allows the desired direct path signal to be completely decoupled from the multipath signals. Examples with both narrowband and broadband signals are presented.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124577741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A broadband, multi-channel source-receive array for ocean acoustics research","authors":"J. Skinner, W. Hodgkiss","doi":"10.23919/OCEANS.2009.5422118","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422118","url":null,"abstract":"A new broadband source-receive array (SRA) has been developed at the SIO Marine Physical Laboratory for use in acoustics research experiments at sea. The SRA specifically was designed for the investigation of acoustic propagation perturbations caused by environmental fluctuations and MIMO (multiple-input/multiple-output) acoustic data communications research over the 10 to 32 kHz frequency band. The technical details of the transducer array and transmitting/recording electronics as well as a description of the different deployment configurations are provided. In addition, the use of the SRA in acoustic data communications research is discussed. Specifically, deployment of the system as a source array during the KAM08 (Kauai Acomms MURI 2008) Experiment is described along with examples of data transmissions from the 52.5 m aperture source array (7.5 m element spacing) deployed in 110 m deep water immediately west of Kauai.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124793813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Benthic community response to hypoxia: Baseline data","authors":"S. Shivarudrappa, K. Briggs, V. Hartmann","doi":"10.23919/OCEANS.2009.5422233","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422233","url":null,"abstract":"World wide more than 400 aquatic systems are hypoxic, affecting an area of more than 245,000 square kilometers. The hypoxic area in Gulf of Mexico is the second largest in the world next to the Baltic Sea basin. In the northern Gulf of Mexico hypoxia is a phenomenon which occurs when the seasonal thermohaline stratification in the water column develops. Under normoxic or hypoxic conditions benthic organisms affect the physicochemical properties of sediment by their usual biological activity such as feeding, locomotion, and burrowing. According to the Pearson-Rosenberg model, changes in the benthos due to hypoxia occur at the community level of organization, with the pioneering community having different biological behavior than the equilibrium community, which normally exists without hypoxic stress. These changes as a response to low oxygen include numerical density, species diversity, organism size, depth of bioturbation, and number of functional groups-all factors which ultimately can affect the physicochemical properties of sediment. Thus, to some extent there may be a feedback mechanism that conditions the sediment properties for the particular type of benthic community. The types of sediment properties that can affect the density and diversity of benthos include grain size distribution, bulk density, and concentration of organic matter. To study these changes, macrobenthos and sediment samples were collected from the northern Gulf of Mexico between the Atchafalaya and Mississippi Rivers. Four provinces were chosen based on the frequency of occurrence of hypoxic events for a comparison between pre-hypoxic conditions in early spring and hypoxic conditions in late summer. The macrobenthos data will be compared with the sediment properties of grain size, organic matter concentration, sedimentation rate, and depth of the redox potential discontinuity to help explain the variability in the biological data among provinces. The macrobenthos data will be statistically analyzed for species richness using Hurlbert rarefaction curves that enable the calculation of the richness for a set number of species, organism sizes, bioturbation depths, and functional groups. The macrobenthos data will be correlated with sediment properties using the principal component analysis. These baseline data will be compared with similar data collected in September for assessing the effects of hypoxia on benthic community structure in the northern Gulf of Mexico.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129582547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NOAA's Physical Oceanographic Real-Time Systems (PORTS®)","authors":"D. Wright, R. Bassett","doi":"10.23919/OCEANS.2009.5422301","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422301","url":null,"abstract":"NOAA's Center for Operational Oceanographic Products and Services (CO-OPS) has developed the Physical Oceanographic Real-Time System (PORTS®) to meet the specific needs of the local maritime community by measuring, integrating, and disseminating observations of water levels, currents, salinity, wind, and bridge clearance, all of which help mariners successfully guide ships into and out of the Nation's seaports. In several locations, PORTS® also provides forecast model guidance which supports informed decision-making in advance of transit scheduling and loading operations. There are twenty PORTS® supporting 50 seaports nationally; eight of these PORTS® are in the Gulf of Mexico. Using PORTS® information in conjunction with NOAA Nautical Charts and US Coast Guard (USCG) Navigational Aids has proven to reduce groundings by as much as 50 percent (%). Future enhancements include integrating PORTS® data with other operational data disseminated via the USCG Automated Identification System (AIS), the integration of wave information, as well as a customizable PORTS® display system that creates personalized and preferred views of data products on the web.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129281074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Developing best practices for IOOS web portals","authors":"David W. Jones, J. Olsonbaker","doi":"10.23919/OCEANS.2009.5422069","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422069","url":null,"abstract":"The Regional Associations (RAs) of IOOS have developed web portals to deliver oceanographic data and information to a diverse range of users. Our research task here is to discover ways of measuring how effectively IOOS web portals are delivering that data and information. Good measurement techniques can help the IOOS community improve its support to users through the development of best practices. In our examination of 10 RA web portals we found the main questions are: If IOOS is about getting data, how easy is it to locate, and then to use? We consider usability testing as a means for evaluating the effectiveness of web portals and discuss three exploratory assessments with regards to navigation, search, and content. The authors anticipate future, more in-depth research on how to maximize web portal usability for the diverse base of IOOS stakeholders.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123397060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salt Water Activated Power System (SWAPS) for ocean buoys and related platforms","authors":"M. W. Turner, J. Cleland, J. Baker","doi":"10.23919/oceans.2009.5422338","DOIUrl":"https://doi.org/10.23919/oceans.2009.5422338","url":null,"abstract":"Ocean buoys often rely on batteries, solar cells, and wind and wave generated power to drive on-board instrumentation and communications equipment. Power demands are increasing as instrument requirements are added and deployment times extended. Un-tethered, station-keeping buoys also use much more energy and power for propulsion. Mil3, Inc has developed a superior Seawater Activated Power Source (SWAPSTM, patent-applied) which is more portable, safe, and economical for marine buoys and related applications. SWAPS utilizes a metal alloy reacting with saltwater to produce hydrogen as fuel for proton exchange membrane (PEM) fuel cells to produce electricity at efficiencies approaching 50%. With an energy density of 1.4 kWh/kg and scalability for power requirements of watts to kilowatts, SWAPS is lighter and less expensive than batteries, and can always produce 100% of its design output power. The only chemical by-product is a metal hydroxide which naturally occurs in seawater. SWAPS stores potential energy in its alloy fuel, provides power on-demand, is inherently self-regulating, and requires no moving parts or external control In contrast, batteries represent low energy density, excessive mass and volume and prohibitive costs for many applications. Bulky solar panels, and wind and wave driven generators do not provide energy storage and are dependent on factors such as time of day, weather conditions, tides, currents, and wind velocity. The best of these technologies may only produce 45% of its design power, which requires over-sizing and energy storage by batteries. Mil3 has proved the operation of an 80 W SWAPS unit on a prototype buoy representing a large meteorological buoy to be deployed for 6 months. Together with Falmouth Scientific Inc., Mil3 has also successfully demonstrated the use of a 35 kWh SWAPS unit to provide 180 W (220 W peak) to a station-keeping spar buoy built for the Navy. In sea states between 3 and 4, SWAPS consistently powered the buoy prop motor against currents greater than 1 knot, all instrumentation and radio telemetry, while additionally charging a Li-ion backup battery. The team is preparing a new SWAPS unit for providing all power for a 40 kW Navy acoustic pulsed power system.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"158 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120905008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple-access communications for underwater acoustic sensor networks using OFDM-IDMA","authors":"L. Linton, P. Conder, M. Faulkner","doi":"10.23919/OCEANS.2009.5422328","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422328","url":null,"abstract":"In this paper, we present a novel multiple-access communications scheme that provides robust performance in the presence of large time-delay spread and the other channel impairments commonly encountered in shallow water acoustic sensor networks. The scheme is based on Orthogonal Frequency Division Multiplexing (OFDM) with an Interleave-Division Multiple Access (IDMA) overlay, where IDMA is a variant of Code-Division Multiple Access (CDMA). Simulations of various underwater acoustic sensor network scenarios show that the OFDM-IDMA scheme consistently outperforms other common multiple-access schemes in the shallow water environment.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114528644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation and compensation of frequency dependent path loss over OFDM subcarriers in UAC","authors":"Sadia Ahmed, H. Arslan","doi":"10.23919/OCEANS.2009.5422159","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422159","url":null,"abstract":"The underwater acoustic communication (UAC) channel presents severe time, space, and frequency selectivity that makes it difficult to achieve high data rate communication. In the recent years OFDM is used to resolve primarily frequency selectivity among these problems. Due to high absorbency of water over small frequency range path loss may be highly variable over OFDM subcarriers. This paper will evaluate this varying path loss and present algorithm to compensate such path loss using adaptive power control, adaptive modulation order, and adaptive BW. To the best knowledge of the authors, evaluation and compensation of varying path loss in the proposed method has not been presented before. Thus this research presents a valuable work in this domain.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116180742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}