Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1192018
S. Fantone, O. Leitermann, J. Austin-Breneman, A.S. Eastment, E. Crumlin
A team of freshman students was presented with the ambiguous challenge of designing an AUV (autonomous underwater vehicle) the size of a wallet. A Micro-AUV would be small enough to avoid many of the transport problems. Because of the potentially simple design of such an AUV, purchase and maintenance costs could be kept fairly low. An AUV such as Pipsqueak would likely be deployed into a lake river, where its size and the environment would allow it to investigate most efficiently. It could also be released in low current ocean areas, such as along beaches or coral reefs. In the future, we predict that as the Micro-AUVs develop and become more efficient and powerful, they might be used for deeper and more intense exploration. In this design, depth is sensed with a pressure gauge such as the Omega DPG1000. Temperature is measured with temperature sensors such as the Seabird 3Bfplus. Images of the surrounding environment would be useful in gathering scientific data. We specified using a CCD or CMOS camera that can interface with the micro controller and satisfy the volume requirements. There are large numbers of low cost, compact digital imaging cameras available today that can be readily incorporated into Pipsqueak. We propose to use the prebuilt RAMCAM from Spectronix. The dead reckoning, inertial based navigation system would be used for this vehicle. This system would have two rear facing horizontal thrusters, and one top facing vertical thruster, which will allow for turning as well as up and down motion.
{"title":"The autonomous underwater vehicle \"Pipsqueak\"","authors":"S. Fantone, O. Leitermann, J. Austin-Breneman, A.S. Eastment, E. Crumlin","doi":"10.1109/OCEANS.2002.1192018","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192018","url":null,"abstract":"A team of freshman students was presented with the ambiguous challenge of designing an AUV (autonomous underwater vehicle) the size of a wallet. A Micro-AUV would be small enough to avoid many of the transport problems. Because of the potentially simple design of such an AUV, purchase and maintenance costs could be kept fairly low. An AUV such as Pipsqueak would likely be deployed into a lake river, where its size and the environment would allow it to investigate most efficiently. It could also be released in low current ocean areas, such as along beaches or coral reefs. In the future, we predict that as the Micro-AUVs develop and become more efficient and powerful, they might be used for deeper and more intense exploration. In this design, depth is sensed with a pressure gauge such as the Omega DPG1000. Temperature is measured with temperature sensors such as the Seabird 3Bfplus. Images of the surrounding environment would be useful in gathering scientific data. We specified using a CCD or CMOS camera that can interface with the micro controller and satisfy the volume requirements. There are large numbers of low cost, compact digital imaging cameras available today that can be readily incorporated into Pipsqueak. We propose to use the prebuilt RAMCAM from Spectronix. The dead reckoning, inertial based navigation system would be used for this vehicle. This system would have two rear facing horizontal thrusters, and one top facing vertical thruster, which will allow for turning as well as up and down motion.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132452671","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}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191895
F.T. Thwaites, C. Davis
We have developed a towed, flyable fish for the Video Plankton Recorder that can fly vertically, horizontally, and hold a constant depth. The Video Plankton Recorder (VPR) has been developed to sample plankton taxa distributions over a broad range of scales. This new fish, or instrument platform, is part of a project to develop a second-generation towed VPR. Associated upgrades to camera and image processing will be discussed elsewhere. The previous towed VPR was mounted on a depressor fin and was winched up and down from a tow-ship and could automatically determine plankton taxa underway. The needs of the new VPR are that the fish to be towable at a ship speed of 5 m/s with the fish flying at 200 m depth, fly rapidly between different depths to allow denser horizontal sampling, have a horizontal optical path, fly out of the ship's wake into undisturbed water, and have minimal disturbance of the water in the optically sampled volume by the cable, bridle, or two-fish. The new tow-fish system has been towed at up to 6 m/s and has sample from the surface down to 200 m depth. The fish has three servos controlling three fins to control pitch, yaw, and roll. The yaw control is needed to fly the fish horizontally out of the tow-ship's wake when the fish is near the surface. At a 5 m/s design tow speed, dynamic roll control is needed because the restoring moment, from a separation of the center of buoyancy and center of gravity, is swamped by hydrodynamic moment, from the separation of the center of buoyancy and center of gravity, is swamped by hydrodynamic moments. For the fish to be stable at a constant shallow depth, the tow bridle does not make the system stable in roll as it can when the fish is pulling downwards. The challenges of the control system are to control the fast response to roll and pitch in the presence of disturbances from cable strumming and surface waves. The fish has a PC-104 format computer controller sampling an inertial measurement unit consisting of three-axis rate gyros and three-axis accelerometers. The fish system has a PC on the surface in the two-ship to display and record engineering data and to communicate supervisory instructions to the PC-104 computer in the fish. The new fish uses a smaller 8.18 mm (0.322 inch) diameter cable allowing the use of a smaller, lighter winch and has been towed from a 14 metre boat.
{"title":"Deployment of a towed, flyable fish for the Video Plankton Recorder","authors":"F.T. Thwaites, C. Davis","doi":"10.1109/OCEANS.2002.1191895","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191895","url":null,"abstract":"We have developed a towed, flyable fish for the Video Plankton Recorder that can fly vertically, horizontally, and hold a constant depth. The Video Plankton Recorder (VPR) has been developed to sample plankton taxa distributions over a broad range of scales. This new fish, or instrument platform, is part of a project to develop a second-generation towed VPR. Associated upgrades to camera and image processing will be discussed elsewhere. The previous towed VPR was mounted on a depressor fin and was winched up and down from a tow-ship and could automatically determine plankton taxa underway. The needs of the new VPR are that the fish to be towable at a ship speed of 5 m/s with the fish flying at 200 m depth, fly rapidly between different depths to allow denser horizontal sampling, have a horizontal optical path, fly out of the ship's wake into undisturbed water, and have minimal disturbance of the water in the optically sampled volume by the cable, bridle, or two-fish. The new tow-fish system has been towed at up to 6 m/s and has sample from the surface down to 200 m depth. The fish has three servos controlling three fins to control pitch, yaw, and roll. The yaw control is needed to fly the fish horizontally out of the tow-ship's wake when the fish is near the surface. At a 5 m/s design tow speed, dynamic roll control is needed because the restoring moment, from a separation of the center of buoyancy and center of gravity, is swamped by hydrodynamic moment, from the separation of the center of buoyancy and center of gravity, is swamped by hydrodynamic moments. For the fish to be stable at a constant shallow depth, the tow bridle does not make the system stable in roll as it can when the fish is pulling downwards. The challenges of the control system are to control the fast response to roll and pitch in the presence of disturbances from cable strumming and surface waves. The fish has a PC-104 format computer controller sampling an inertial measurement unit consisting of three-axis rate gyros and three-axis accelerometers. The fish system has a PC on the surface in the two-ship to display and record engineering data and to communicate supervisory instructions to the PC-104 computer in the fish. The new fish uses a smaller 8.18 mm (0.322 inch) diameter cable allowing the use of a smaller, lighter winch and has been towed from a 14 metre boat.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132893545","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}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1192138
R. Dekeyzer, J. S. Byrne, J.D. Case, B. Clifford, W. Simmons
Significant improvements in the quality of imagery data available from multibeam echo sounders have recently been made. The intensity time series values are derived from the same transmit beam pattern that produces the sounding values. This sampling approach provides a dataset with co-located bathymetry and imagery. This paper presents examples of seafloor features imaged with both a Klein system 2000 towed side scan sonar and with Reson 8100 series multibeam echo sounders. The multibeam echo sounder imagery presented is derived from the receive beams formed to make the bathymetric measurements. The comparison focuses on depths shallower than 40 metres, and including a variety of terrains surveyed along the northeastern US. The areas investigated include hydrographically significant bottom features and multiple benthic habitats imaged with both types of systems. This paper demonstrates the contribution that can be made when the multibeam echo sounder imagery data is acquired and processed along with the bathymetry data from a multibeam echo sounder. The imagery data can provide complimentary information during the processing and analysis phases of data reduction. While the resulting imagery is not as sharp as the imagery from a towed side scan sonar, the resulting dataset does offer some significant advantages. This approach can support a wide range of survey applications including: hydrography, search and locate, route survey, habitat mapping, and seafloor characterization.
{"title":"A comparison of acoustic imagery of sea floor features using a towed side scan sonar and a multibeam echo sounder","authors":"R. Dekeyzer, J. S. Byrne, J.D. Case, B. Clifford, W. Simmons","doi":"10.1109/OCEANS.2002.1192138","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192138","url":null,"abstract":"Significant improvements in the quality of imagery data available from multibeam echo sounders have recently been made. The intensity time series values are derived from the same transmit beam pattern that produces the sounding values. This sampling approach provides a dataset with co-located bathymetry and imagery. This paper presents examples of seafloor features imaged with both a Klein system 2000 towed side scan sonar and with Reson 8100 series multibeam echo sounders. The multibeam echo sounder imagery presented is derived from the receive beams formed to make the bathymetric measurements. The comparison focuses on depths shallower than 40 metres, and including a variety of terrains surveyed along the northeastern US. The areas investigated include hydrographically significant bottom features and multiple benthic habitats imaged with both types of systems. This paper demonstrates the contribution that can be made when the multibeam echo sounder imagery data is acquired and processed along with the bathymetry data from a multibeam echo sounder. The imagery data can provide complimentary information during the processing and analysis phases of data reduction. While the resulting imagery is not as sharp as the imagery from a towed side scan sonar, the resulting dataset does offer some significant advantages. This approach can support a wide range of survey applications including: hydrography, search and locate, route survey, habitat mapping, and seafloor characterization.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132056531","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}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1193253
S. Theophanis
The impact burial of anti-ship bottom mines in soft seafloors is dependent on the sediment properties and the velocity and orientation of the mine at the time of impact. A full-scale instrumented mine has been constructed to measure descent trajectory and velocity for ground truthing of hydrodynamic model predictions. A dynamic measurement unit (DMU) supplied by Crossbow Technology is the primary sensor employed for this measurement. The six channels of data provided by the DMU are three orthogonal DC coupled accelerations, and three angular rates (about the axis system defined by the accelerometers). We develop a signal processing algorithm that converts the raw DMU data into a time history of the mine's position and orientation during deployment. The algorithm is then tested on DMU data gathered from well-characterized instrument motion to quantify the accuracy of our measurement capability.
{"title":"Accelerometer and fiber optic gyro measurements of an instrumented cylinder used to study impact burial","authors":"S. Theophanis","doi":"10.1109/OCEANS.2002.1193253","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1193253","url":null,"abstract":"The impact burial of anti-ship bottom mines in soft seafloors is dependent on the sediment properties and the velocity and orientation of the mine at the time of impact. A full-scale instrumented mine has been constructed to measure descent trajectory and velocity for ground truthing of hydrodynamic model predictions. A dynamic measurement unit (DMU) supplied by Crossbow Technology is the primary sensor employed for this measurement. The six channels of data provided by the DMU are three orthogonal DC coupled accelerations, and three angular rates (about the axis system defined by the accelerometers). We develop a signal processing algorithm that converts the raw DMU data into a time history of the mine's position and orientation during deployment. The algorithm is then tested on DMU data gathered from well-characterized instrument motion to quantify the accuracy of our measurement capability.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132061545","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}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191891
E. Widder
The most common sources of planktonic bioluminescence are dinoflagellates, copepods, euphausiids, ostracods and gelatinous zooplankton. Each of these has very distinctive flash characteristics that make them easy to distinguish from each other. Using an intensified video camera mounted on a mid-water submersible we have developed the Spatial Plankton Analysis Technique (SPLAT) that identifies and maps the 3-dimensional microscale distribution patterns of bioluminescent plankton. The unique temporal and spatial characteristics of luminescent displays permit identification of many sources to the species level, and the exceptional signal-to-noise ratio afforded by a self-luminous source means that even microscopic organisms, such as a 50 /spl mu/m dinoflagellate, can be identified in a field of view of 1 m. Recently we have adapted the SPLAT CAM for deployment on the HIDEX-BP (High Intake Defined Excitation BathyPhotometer). This vertical profiling system was developed for the U.S. Navy (Naval Oceanographic Office-NAVOCEANO) for routine monitoring of bioluminescence in the oceans. The high pumping rate of this BP (18 l/s) assures a high statistical significance and a high-resolution profile of bioluminescence potential in the water column. By combining this capability with the plankton identification afforded by the SPLAT CAM, the utility of both systems is greatly enhanced. The resulting data should prove valuable for a wide range of applications such as defining the geographical boundaries of dinoflagellate blooms, tracking movement patterns of bioluminescent vertical migrators, monitoring temporal changes in the abundance of grazers as a function of environmental variables and primary production, assessing the production of primary sources of nutrition for commercially important fish species and providing data needed for NSW nowcasts and forecasts.
浮游生物发光最常见的来源是鞭毛类、桡足类、棘足类、介形虫和胶状浮游动物。每一种都有非常独特的闪光特征，这使得它们很容易区分开来。利用安装在中水潜水器上的强化摄像机，我们开发了空间浮游生物分析技术(SPLAT)，该技术可以识别和绘制生物发光浮游生物的三维微尺度分布模式。发光显示器独特的时间和空间特性允许识别许多物种水平的光源，并且自发光光源提供的特殊信噪比意味着即使是微生物，如50 /spl μ m /m的鞭毛藻，也可以在1米的视野内识别。最近，我们将SPLAT CAM用于部署在HIDEX-BP(高进气定义激发深度光度计)上。这种垂直剖面系统是为美国海军(海军海洋学办公室- navoceano)开发的，用于对海洋中的生物发光进行常规监测。该BP的高泵送速率(18l /s)确保了高统计显著性和水柱中生物发光电位的高分辨率剖面。通过将这种能力与SPLAT CAM提供的浮游生物识别相结合，这两个系统的效用大大增强。由此产生的数据将被证明具有广泛的应用价值，如定义鞭毛藻华的地理边界，跟踪生物发光垂直迁徙者的运动模式，监测食草动物丰度的时间变化，作为环境变量和初级生产的函数，评估商业上重要鱼类的主要营养来源的生产，并为新南威尔士州的临近预报和预测提供所需的数据。
{"title":"SPLAT CAM: mapping plankton distributions with bioluminescent road-kill","authors":"E. Widder","doi":"10.1109/OCEANS.2002.1191891","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191891","url":null,"abstract":"The most common sources of planktonic bioluminescence are dinoflagellates, copepods, euphausiids, ostracods and gelatinous zooplankton. Each of these has very distinctive flash characteristics that make them easy to distinguish from each other. Using an intensified video camera mounted on a mid-water submersible we have developed the Spatial Plankton Analysis Technique (SPLAT) that identifies and maps the 3-dimensional microscale distribution patterns of bioluminescent plankton. The unique temporal and spatial characteristics of luminescent displays permit identification of many sources to the species level, and the exceptional signal-to-noise ratio afforded by a self-luminous source means that even microscopic organisms, such as a 50 /spl mu/m dinoflagellate, can be identified in a field of view of 1 m. Recently we have adapted the SPLAT CAM for deployment on the HIDEX-BP (High Intake Defined Excitation BathyPhotometer). This vertical profiling system was developed for the U.S. Navy (Naval Oceanographic Office-NAVOCEANO) for routine monitoring of bioluminescence in the oceans. The high pumping rate of this BP (18 l/s) assures a high statistical significance and a high-resolution profile of bioluminescence potential in the water column. By combining this capability with the plankton identification afforded by the SPLAT CAM, the utility of both systems is greatly enhanced. The resulting data should prove valuable for a wide range of applications such as defining the geographical boundaries of dinoflagellate blooms, tracking movement patterns of bioluminescent vertical migrators, monitoring temporal changes in the abundance of grazers as a function of environmental variables and primary production, assessing the production of primary sources of nutrition for commercially important fish species and providing data needed for NSW nowcasts and forecasts.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131706637","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}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1193247
D. DelBalzo, K.P. Hemsteter
GRASP (Genetic Range-dependent Algorithm for Search Planning) was developed to nearly optimize sonar search patterns in complicated environments. The standard scenario is to maximize cumulative detection probability (CDP) for several ASW searchers against a randomly patrolling threat. An improvement to the algorithms allows the target to counter-detect an active sonar pulse and to maneuver away from the searcher. In general, the CDP is reduced dramatically by evasive maneuvers, since the counter-detection range is usually greater than the detection range. The analysis covers several combinations of platforms and sensors in artificial environments. The GRASP solutions show significant benefit, especially against an evading target. GRASP joint tactics exploit target evasive maneuvers to significantly increase detection performance relative to non-joint tactics. A somewhat surprising result is that as the target evasion range increases (better intercept receiver), the multi-sensor CDP increases in an explainable way. The advantages of multi-platform and multisensor ASW search plans are described in terms of improved performance and reduced search time.
{"title":"GRASP multi-sensor search tactics against evading targets","authors":"D. DelBalzo, K.P. Hemsteter","doi":"10.1109/OCEANS.2002.1193247","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1193247","url":null,"abstract":"GRASP (Genetic Range-dependent Algorithm for Search Planning) was developed to nearly optimize sonar search patterns in complicated environments. The standard scenario is to maximize cumulative detection probability (CDP) for several ASW searchers against a randomly patrolling threat. An improvement to the algorithms allows the target to counter-detect an active sonar pulse and to maneuver away from the searcher. In general, the CDP is reduced dramatically by evasive maneuvers, since the counter-detection range is usually greater than the detection range. The analysis covers several combinations of platforms and sensors in artificial environments. The GRASP solutions show significant benefit, especially against an evading target. GRASP joint tactics exploit target evasive maneuvers to significantly increase detection performance relative to non-joint tactics. A somewhat surprising result is that as the target evasion range increases (better intercept receiver), the multi-sensor CDP increases in an explainable way. The advantages of multi-platform and multisensor ASW search plans are described in terms of improved performance and reduced search time.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131749509","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}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191900
N. Trenaman, P. Devine, B. Strong
During the last couple of years, RDI's WorkHorse ADCP has provided a new method to measure unambiguous directional wave spectra, current profiles, and water level at the same time. Much more than duplicating traditional methods and devices, a single ADCP provides a spatial array of measurements for measuring the wave field directly. This array enables creation of high-definition polar plots of wave direction that separate, rather than smear, waves of similar frequency from multiple directions. ADCPs measure a complete frequency-direction wave spectrum. Further, the ADCP measures the surface-layer currents that can distort the wave field. Recent results are shown that demonstrate the unique advantages of this new technology - notably an ADCP-based analysis of waves can avoid some of the assumptions required by more traditional methods because new types of data are being collected by the ADCP. This new capability is available as an upgrade for WorkHorse ADCPs in the field.
{"title":"ADCP-based multidirectional wave gauge and current profiling","authors":"N. Trenaman, P. Devine, B. Strong","doi":"10.1109/OCEANS.2002.1191900","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191900","url":null,"abstract":"During the last couple of years, RDI's WorkHorse ADCP has provided a new method to measure unambiguous directional wave spectra, current profiles, and water level at the same time. Much more than duplicating traditional methods and devices, a single ADCP provides a spatial array of measurements for measuring the wave field directly. This array enables creation of high-definition polar plots of wave direction that separate, rather than smear, waves of similar frequency from multiple directions. ADCPs measure a complete frequency-direction wave spectrum. Further, the ADCP measures the surface-layer currents that can distort the wave field. Recent results are shown that demonstrate the unique advantages of this new technology - notably an ADCP-based analysis of waves can avoid some of the assumptions required by more traditional methods because new types of data are being collected by the ADCP. This new capability is available as an upgrade for WorkHorse ADCPs in the field.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126685404","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}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191857
M. Inoue, Dongho Park, D. Justić, W. Wiseman
The Barataria Basin, a bar-built estuarine system located directly west of the Mississippi Delta, has been experiencing a significant land loss, especially since the leveeing of the Mississippi River for flood control purposes in early 20th century. Recent efforts to alleviate the land loss problem include the construction of man-made freshwater diversion structure in order to divert river water as well as its associated suspended sediments from the Mississippi River into the Barataria Basin. In order to implement an ecologically friendly management plan of those diversions, a careful examination of the anticipated salinity alterations resulting from the operation of the diversions is required. A high-resolution (O(100m)), integrated hydrology-hydrodynamic model of the Barataria Basin has been developed to simulate the local hydrological cycle over the surrounding drainage basin and hydrodynamics within the basin. The integrated model is forced by observed tides coming from the Gulf of Mexico, local wind, rainfall and evaporation over the model domain, salinity and temperature estimated at the open boundary located offshore of the mouth of the bay. Estimated local precipitation and evaporation over the model domain provide hydrological forcing of the hydrological model, that in turn simulates local runoff into the hydrodynamic model. A novel feature of the hydrodynamic model is its use of a very accurate advection scheme, thus, enabling accurate simulation of salinity variations in response to changes in various hydrological forcing functions. A flood event that took place during the tropical storm Allison in June 2001 resulted in significant sea-level changes especially in the upstream region of the basin. The integrated model appears to be able to capture a significant portion of the observed sea-level variations during the flood. Significant effects on water level and salinity are observed in the multiply connected channels through the marsh in the vicinity of operating diversion structure and in the open waters downstream.
{"title":"A high-resolution integrated hydrology-hydrodynamic model of the Barataria Basin system","authors":"M. Inoue, Dongho Park, D. Justić, W. Wiseman","doi":"10.1109/OCEANS.2002.1191857","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191857","url":null,"abstract":"The Barataria Basin, a bar-built estuarine system located directly west of the Mississippi Delta, has been experiencing a significant land loss, especially since the leveeing of the Mississippi River for flood control purposes in early 20th century. Recent efforts to alleviate the land loss problem include the construction of man-made freshwater diversion structure in order to divert river water as well as its associated suspended sediments from the Mississippi River into the Barataria Basin. In order to implement an ecologically friendly management plan of those diversions, a careful examination of the anticipated salinity alterations resulting from the operation of the diversions is required. A high-resolution (O(100m)), integrated hydrology-hydrodynamic model of the Barataria Basin has been developed to simulate the local hydrological cycle over the surrounding drainage basin and hydrodynamics within the basin. The integrated model is forced by observed tides coming from the Gulf of Mexico, local wind, rainfall and evaporation over the model domain, salinity and temperature estimated at the open boundary located offshore of the mouth of the bay. Estimated local precipitation and evaporation over the model domain provide hydrological forcing of the hydrological model, that in turn simulates local runoff into the hydrodynamic model. A novel feature of the hydrodynamic model is its use of a very accurate advection scheme, thus, enabling accurate simulation of salinity variations in response to changes in various hydrological forcing functions. A flood event that took place during the tropical storm Allison in June 2001 resulted in significant sea-level changes especially in the upstream region of the basin. The integrated model appears to be able to capture a significant portion of the observed sea-level variations during the flood. Significant effects on water level and salinity are observed in the multiply connected channels through the marsh in the vicinity of operating diversion structure and in the open waters downstream.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121387717","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}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1193308
J.C. Smith
This paper is adapted from a Masters thesis completed by the author. Experimental wind tunnel studies were conducted in an attempt to reduce drag over a cylindrical buoy at low Reynolds numbers. Two high thickness to chord ratio sections were tested to determine their aerodynamic coefficients, aerodynamic centers, and stability about the mooring point. Results indicate that drag reduction on the order of 75 to 90% over the tested range of velocities is possible. Although promising, drag and stability results come with important caveats. One fairing section was found to be unstable if held at the thickest section, while demonstrating the best drag performance. The other section is sensitive to surface conditions and Reynolds number effects, yet is fully stable and has a compact form. Engineers are left with important decisions: attempt to stabilize the low drag section and realize the largest drag benefits, or use the stable section and accept higher drag for a more compact package. Although both solutions have associated risks, large performance gains and reduced costs are possible.
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Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191999
E. Shybanov, V. I. Haltrin
A new and efficient computational approach to calculate Mie scattering of light by spherical particles, including very large ones, is presented. The code based on this approach is capable to compute light scattering by absorbing particles with size parameters up to sixteen million, and by nonabsorbing spherical particles with size parameters as large as one billion. This feature is very important for modeling scattering properties of coastal ocean waters containing suspended sand grains, clay and large detritus particles.
{"title":"Scattering of light by hydrosol particles suspended in coastal waters","authors":"E. Shybanov, V. I. Haltrin","doi":"10.1109/OCEANS.2002.1191999","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191999","url":null,"abstract":"A new and efficient computational approach to calculate Mie scattering of light by spherical particles, including very large ones, is presented. The code based on this approach is capable to compute light scattering by absorbing particles with size parameters up to sixteen million, and by nonabsorbing spherical particles with size parameters as large as one billion. This feature is very important for modeling scattering properties of coastal ocean waters containing suspended sand grains, clay and large detritus particles.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121553436","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}
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