OCEANS 2009最新文献

{"title":"Determining coastal water sampling frequencies using a profiling mooring","authors":"A. Devol, W. Ruef, J. Newton","doi":"10.23919/OCEANS.2009.5422253","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422253","url":null,"abstract":"As part of the Northwest Association of Networked Ocean Observing Systems (NANOOS), a mooring is maintained in Pu-get Sound, WA that makes water-column profiles for temperature, salinity, oxygen, fluorescence, turbidity, nitrate and currents as well as surface pCO2 and air pCO2 every two hours. Additionally, 10-minute averages of the meteorological data (atmospheric temperature, wind velocity, wind direction, relative humidity, solar radiation) are also taken. All data is telemetered back to a laboratory computer in near-real time, where it is automatically processed and posted to the Internet. Analysis of data obtained from the mooring for the summer 150 day growing season are used to determine the frequency of sampling at this site necessary to characterize various parameters. High frequency variability is characteristic of the study site and the variability is caused by a combination of tidal advection of horizontal patchiness as well wind induced destabilization of the mixed layer. The analysis suggest that sampling frequencies on the order of hours to weekly are required to resolve the seasonal cycles and true values of various parameters and variables.","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":"124997194","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":"Performance of the first year of the completed US operational deep-sea tsunameter network","authors":"R. Bouchard, C. Kohler, P. Lessing, K. Kern","doi":"10.23919/OCEANS.2009.5422066","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422066","url":null,"abstract":"In March 2008, the National Oceanic and Atmospheric Administration's (NOAA) National Data Buoy Center (NDBC) completed the deployment of the full 39-station network of deep-sea tsunameters bolstering the U.S. tsunami warning system. This vast network of 39 stations provides coastal communities in the Pacific, Atlantic, Caribbean and the Gulf of Mexico with faster and more accurate tsunami warnings. The tsunameters employ the patented technology of the second generation Deep-ocean Assessment and Reporting of Tsunamis (DART® Π). A full year of operating the completed network provided a host of challenges and accomplishments. Data availability statistics missed the operating goal of 80%, primarily due to a rash of mooring failures. Most of these failures occurred in regions of strong ocean currents — the Kuroshio Current, the Loop Current of the Gulf of Mexico, and the Gulf Stream. Stations in the western North Pacific Ocean experienced prolonged outages because of the great distances from staging areas and persistent stormy weather and their proximity to major storm tracks. However, in 2007 the mooring and system at station 42407, in the Caribbean, had exceeded design specifications by weathering the passage of Hurricane Dean, when it was a Category 4 hurricane. In the spring and summer of 2009, a series of ambitious service cruises will return the network to nearly full operating capability. Focusing on ways to reduce future outages, NDBC undertook a number of engineering initiatives, including an intensive investigation into the mooring failures and deployed several new mooring types for evaluation and obtained warehouse space in Guam to reduce logistical requirements. In response to requirements from the US Tsunami Warning Centers (TWC) — the Pacific Tsunami Warning Center, Ewa Beach, Hawai'i and the West Coast/Alaska Tsunami Warning Center, Palmer, Alaska — the 2009 deployments included new firmware that provided the TWCs more control and improved initiating event or rapid reporting mode. Previous firmware versions added an artificial 100 mm to the estimated water-column height in order to initiate and indicate rapid reporting mode by command from the TWCs. Command-initiated modes are now distinguished from on-board-initiated modes by new message identifiers. NDBC made changes to the electronics to reduce the number of false event modes that have made up about a third of all event mode initiations. The changes will also prevent the corruption of transmitted data caused by feedback during the acoustic transmissions. In 2009, NDBC completed the initial field test and evaluation of its new Standard Buoy, configured for tsunameter operations and its first operational use at Station 46412. The Standard Buoy will provide a common, lower-cost platform that can be used interchangeably with NDBC's other buoy programs — Weather and Oceanographic Platforms (WxOP) and the Tropical Atmosphere Ocean (TAO) Array Buoys. In addition, Standard Buoys will have th","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"44 3 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":"125327411","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":"An enhanced underwater positioning system to support deepwater installations","authors":"H. Tan, Zhi Ang Eu, W. Seah","doi":"10.23919/OCEANS.2009.5422093","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422093","url":null,"abstract":"In the offshore engineering community, deep underwater construction activities such as installation of mooring systems for oil and gas extraction require payloads such as subsea templates, Christmas trees and manifolds to be installed accurately. In this paper, we consider a recently proposed underwater positioning system (UPS) to support deepwater installations. We identify and demonstrate its shortcomings in harsh underwater acoustic channels. We then propose enhancements to UPS, and demonstrate numerically that our proposed scheme achieves significantly better localization speed, at lower communication costs while preserving the \"silent\" property with a relatively small underwater acoustic sensor network deployed on the seabed in typically underwater channel conditions.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"19 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":"121644465","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 toolbox dedicated to the analysis of airborne SAR sea clutter data","authors":"V. Gras, C. Sintes","doi":"10.23919/OCEANS.2009.5422285","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422285","url":null,"abstract":"The characterization of the sea clutter spatial and statistical properties is a challenging problem for improving the detection performances of any radar system confronted with strong sea clutter perturbations. On the one hand, the use of radar scatterometry made it possible to precisely determine the behavior of the sea surface backscattering coefficient and to confirm electromagnetic models. On the other hand, the imaging of the ocean by radar has been studied extensively and has led to a mature theory of synthetic aperture radar (SAR) imaging of the ocean. Nevertheless the manipulations of SAR data are handicapped by the size of data. In order to analyze SAR data, we need a very flexible tool well adapted to these data. This paper briefly presents the inner functioning of a software (i.e. the different choices of class organization and how it is convenient to use them) based on a multilook philosophy (spectral sub bands processing) and on Octave script. Then we specify the type of operations and processings, we can perform using this software. Two examples of use are presented which show the easiness of use of this software.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"194 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":"121783315","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":"Surveying coastal ship traffic with LANDSAT","authors":"R. Abileah","doi":"10.23919/oceans.2009.5422109","DOIUrl":"https://doi.org/10.23919/oceans.2009.5422109","url":null,"abstract":"A semi-automated algorithm was developed to detect ships in LANDSAT 7 images. The algorithm combines multispectral and pattern recognition methods to discriminate ships from ocean clutter. Automated processing enables us to process a large number of images and gather a statistical picture of ship traffic patterns. As a test case we applied the algorithm on 54 LANDSAT images in the area of Jacksonville, FL, from the period 1999–2003. The area and time period are the same as an earlier ship traffic study by Ward-Geiger et al. using ship reports in the Mandatory Ship Reporting System (MSRS). The similarities between the two studies suggest that LANDSAT is a good alternative for surveying nearshore ship traffic.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"5 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":"127722760","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":"Review of ocean-acoustic models","authors":"P. Etter","doi":"10.23919/OCEANS.2009.5422478","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422478","url":null,"abstract":"This paper describes acoustic models that can generate analytical metrics in support of naval operations, particularly in coastal oceans. Coastal environments are generally characterized by high spatial and temporal variabilities. When coupled with acoustic spectral dependencies of the surface and bottom boundaries, these natural variabilities make coastal regions very complex acoustic environments. Thus, accurate modeling of the acoustic environment is essential for prediction of sonar performance in coastal oceans. The current inventory of ocean-acoustic models comprises 126 propagation models, 19 noise models, 26 reverberation models and 34 sonar-performance models. Approximately 18 percent of this inventory is tailored for shallow-water applications. When coupled with coastal atmosphere-ocean models, these ocean-acoustic models can generate sophisticated prognostic and diagnostic metrics in support of naval operations in coastal oceans.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"19 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":"133754043","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":"Development of a new Unmanned Semi-Submersible (USS) vehicle","authors":"P. Alleman, A. Kleiner, C. Steed, D. Hook","doi":"10.23919/OCEANS.2009.5422294","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422294","url":null,"abstract":"C&C Technologies in Lafayette, LA in cooperation with the Naval Research Laboratory (NRL) Mapping, Charting and Geodesy Branch at Stennis Space Center, MS and Autonomous Surface Vehicles, Ltd. in W. Sussex, UK, is implementing a multiyear development program of an Unmanned Semi-Submersible (USS) vehicle. Originally sponsored by the National Oceanic and Atmospheric Administration (NOAA), the goal of this project is to develop an unmanned, compact, rugged, and high-endurance vehicle capable of acquiring sensor based measurements and yielding higher coverage rates per day in sea states beyond those possible with a small manned conventional survey boat. Furthermore, the USS will facilitate an evaluation of the full potential of a rugged semi-submersible as a low cost force multiplier for littoral mapping purposes in both commercial and military applications. Vehicle attributes include a notable sea-keeping capability that offers promise for nautical charting surveys, military applications, and homeland defense programs. This program builds upon earlier NRL research with the unmanned semi-submersible survey prototype, ORCA (Oceanographic Remotely Controlled Automaton) to support the Naval Oceanographic Office (NAVOCEANO). The ORCA was an air-breathing vessel with a majority of its structure traveling just below the water surface. The ORCA's radio antennae were affixed to a snorkel, which allowed for remote vehicle command and control in addition to real-time data transfer. The ORCA also used Differential Global Positioning System (DGPS) for precise positioning. In a similar fashion, the newly developed USS navigates submerged with only a narrow sail structure extending above the waterline. The USS design criteria are based upon the maximum integration of readily available Commercial Off The Shelf (COTS) hardware and instrumentation acquired largely from small boat technology. Requirements mandate a form factor suitable for stern ramp launch and retrieval, the capacity to operate dockside without special equipment, a re-configurable payload capability, a survey speed of at least six knots, and an endurance of at least two days. Overall vehicle height is restrained to allow for safe maintenance work on the deck of a moving ship and to accommodate shipping and storage within standard ISO containers. The USS program is aimed to provide risk reduction to support the Navy Unmanned Underwater Vehicle (UUV) Master Plan by evaluating new sensors, modularity, commonality of equipment, and experimentation with UUV systems. This paper discusses the USS concept, the decision making process, program milestones, and the vehicle design process including establishment of the performance criteria, hydrodynamic model testing, computer simulation, manufacture, and sea testing results.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"2 5 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":"134401476","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":"GOMEX08 — High frequency acoustic propagation over the Alabama Alps","authors":"R. Field, P. Gallacher, D. Hebert, E. Jarosz","doi":"10.23919/OCEANS.2009.5422266","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422266","url":null,"abstract":"The objective of this work is to diagnose high frequency acoustic propagation directly from oceanographic data and ocean models. To achieve this objective a joint acoustic and oceanographic experiment was performed in the Gulf of Mexico in the summer of 2008. This paper will show that high frequency acoustic propagation at 17.5 kHz tracks the estimated turbulent dissipation rate obtained from field measurements and that ocean modeling gives reasonable estimates of both the turbulent dissipation rate and sound speed. The ocean model sound speed structure is used in an acoustic model to simulate the measured acoustic fluctuations at 17.5 kHz over a four hour period.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"118 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":"134408752","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":"Real-time and long-term monitoring of phosphate using the in-situ CYCLE sensor","authors":"A. Barnard, B. Rhoades, C. Wetzel, A. Derr, J. R. Zaneveld, C. Moore, C. Koch, I. Walsh","doi":"10.23919/OCEANS.2009.5422184","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422184","url":null,"abstract":"Dissolved nutrient dynamics broadly affect issues related to public health, ecosystem status and resource sustainability. Modeling ecosystem dynamics and predicting changes in normal variability due to potentially adverse impacts requires sustained and accurate information on nutrient availability. On site sampling is often resource limited which results in sparse data sets with low temporal and spatial density. For nutrient dynamics, sparse data sets will bias analyses because critical time scales for the relevant biogeochemical processes are often far shorter and spatially limited than sampling regimes. While data on an areal basis will always be constrained economically, an in-situ instrument that provides coherent data at a sub-tidal temporal scale can provide a significant improvement in the understanding of nutrient dynamics and biogeochemical cycles. WET Labs has developed an autonomous in-situ phosphate analyzer which is able to monitor variability in the dissolved reactive phosphate concentration (orthophosphate) for months with a sub-tidal sampling regime. The CYCLE phosphate sensor is designed to meet the nutrient monitoring needs of the community using a standard wet chemical method (heteropoly blue) and minimal user expertise. The heteropoly blue method for the determination of soluble reactive phosphate in natural waters is based on the reaction of phosphate ions with an acidified molybdate reagent to yield molybdophosphoric acid, which is then reduced with ascorbic acid to a highly colored blue phosphomolybdate complex. This method is selective, insensitive to most environmental changes (e.g., pH, salinity, temperature), and can provide detection limits in the nM range. The CYCLE sensor uses four micropumps that deliver the two reagents (ascorbic acid and acidified molybdate), ambient water, and a phosphate standard. The flow system incorporates an integrated pump manifold and fluidics housing that includes controller and mixing assemblies virtually insensitive to bubble interference. A 5-cm pathlength reflective tube absorption meter measures the absorption at 880 nm associated with reactive phosphate concentration. Reagents and an on-board phosphate standard for quality assurance are delivered using a novel and simple-to-use cartridge system that eliminates the user's interaction with the reagents. The reagent cartridges are sufficient for more than 1000 samples. The precision of the CYCLE sensor is ~50 nM phosphate, with a dynamic range from ~0 to 10 μΜ. The CYCLE sensor operates using 12 VDC input, and has a low current draw (milliamps). CYCLE also has 1 GB on-board data storage capacity, and communicates using a serial interface. The host software for the CYCLE sensor includes a variety of features, including deployment planning and sensor configuration, data processing, plotting of raw and processed data, tracking of reagent usage and a pre and post deployment calibration utility. The instrument has been deployed in a variety","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"33 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":"133021669","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":"Microwave-acoustic water level sensor comparisons: Sensor response to change in oceanographie and meteorological parameters","authors":"J. Boon, R. Heitsenrether, Mark Bushneil","doi":"10.23919/OCEANS.2009.5422186","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422186","url":null,"abstract":"The Center for Operational Oceanographie Products and Services (CO-OPS) of the National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce, conducts thorough evaluations of new environmental measurement sensors through its Ocean Systems Test & Evaluation Program. New water level sensors that employ microwave (MW) radar technology are now being evaluated and compared with other devices including the Aquatrak acoustic (AC) sensor that presently serves as the operational standard for the National Water Level Observation Network (NWLON). While no part of a MW radar gage has contact with the water and radar transmission in the GHz range is insensitive to temperature and humidity change, the beam measuring distance to the water surface is allowed to transmit in open air with no confining hardware such as a wave guide or stilling well. Further study is therefore needed to fully understand the effect of a dynamic air-water interface on MW radar measurements. Four MW radar sensors (Sutron RLR-0002, Miros SM-094, Design Analysis H3611 and Ohmart/Vega Vegapuls 62) were mounted on the U.S. Army Corps of Engineers Field Research Facility (FRF) pier at Duck, NC where oceanographie and meteorological data were used to evaluate MW radar sensor performance under open ocean conditions. Water level 6-minute series from each MW sensor were compared with 6-minute series recorded by the NWLON AC sensor at Duck during September-October, 2008. MW-AC zero-mean difference series contained power (variance) at certain frequencies and cross-power (covariance) at these same frequencies with parameters such as wave height, wave steepness, longshore current speed, and air/water temperature ratio. MW-AC differences for all MW sensors showed noticeable change when Hmo wave heights exceeded 2 meters and marked change when Hmo wave heights exceeded 3 meters during storm events. Wave steepness increased abruptly at the onset of these events followed by a prolonged roll-off toward lower values. MW-AC differences for the Sutron and Mros sensors responded first negatively then positively to steepness episodes while the Design Analysis and Vegapuls sensors responded positively but with a noticeable lag during larger events. Coherence analyses for MW-AC difference versus wave height and wave steepness underscore similarities between the Sutron and Miros sensors in one group and between the Design Analysis and Vegapuls sensors in another group, each characterized by a set of distinctive frequencies. The same analyses involving longshore current speed and air/water temperature ratio hint at weaker associations at lunar diurnal and semidiurnal periods for the former and solar diurnal and semidiurnal periods for the latter.","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":"130369907","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}