Kenneth D. Anderson NCCOSC RDTE DIV 883 49170 Propagation Path San Diego, CA 92152-7385 PH: (619)553-1420 FAX: (619)553-1417 INTERNET: kenn@nosc.mil There will be only investigator supporting the GPS Sounder effort. |
The ONR funded GPS Sounder effort uses low-elevation angle measurements of GPS satellite signals to infer the vertical tropospheric refractivity profile from the characteristics of the received interference pattern. One of the crucial aspects to quantify is the effect of surface roughness on the interference null depth. Measurements have been made in the San Diego, CA, offshore area but are limited to low energy surface conditions.
The SandyDuck 97 GPS Sounder measurements will be essentially self-contained, with the exception of an existing shelter or enclosure to support one person with a laptop computer and a hand-held, geodetic quality, GPS receiver. In addition, a small external GPS receiver antenna (possibly mounted to the rails of the pier or to the SIS cab), connected to the receiver using RG-58 coax, is required. If needed, all measurements could be completed using self-contained battery power. However, access to a 110- to 220 VAC (47 to 60 Hz) supply would be advantageous. These measurements will be made for approximately 6 hours per day -- this gives about 8 to 12 satellite observations, which is adequate to quantify surface roughness effects.
I am looking at one week of measurements, I propose using the time period from 9 to 17 October 1997. Deployment (mounting the antenna) would occur on Thursday and Friday, 9 & 10 October. Operations would commence Monday, 13 October, and terminate Friday, 17 October. It is anticipated that te equipment can be removed after measurements are completed on Friday, 17 October.
Funding to support the measurements will be provided by ONR. At this time, the funding situation appears to be good.
There are no instruments in the water. A "patch" antenna, approximately 6 inches in diameter, would be mounted to the pier rails or to the SIS cab and connected to a hand-held receiver, which is controlled by a laptop computer. To maximize satellite coverage it is desirable to locate the equipment at the end of the pier. This location gives the maximum unobstructed view of the horizon and I could use the hut at the end of the pier for a shelter. However, the equipment could be attached to the SIS (not on the boom but on the cab itself) with an impact of reducing the number of available measurements by half.
TITLE: FLUID-SEDIMENT INTERACTIONS IN THE SURF ZONE
R. Beach OSU, COAS 104 Ocean Admin. Bldg Corvallis, OR 97331 PH: (541) 737-3890 FAX: (541) 737-2064 INTERNET: rab@oce.orst.edu |
R. Holman OSU, COAS, 104 Ocean Admin. Bldg. Corvallis, OR 97331 PH: (541) 737-2914 FAX: (541) 737-2064 INTERNET: holman@oce.orst.edu |
R. Sternberg U.W. Oceanography P.O. Box 357940 Seattle, WA 98195 PH: (206) 543-0589 INTERNET: rws@ocean.washington.edu |
A. Ogston U.W. Oceanography P.O. Box 357940 Seattle, WA 98195 PH: (206) 543-0768 INTERNET: ogston@ocean.washington.edu |
This investigation will focus on the horizontal spatial variations of bottom boundary layer processes and sediment transport associated with large-scale fluid forcing within the surf zone, e.g., edge waves, shear waves and mean currents.
A cross-shore and longshore array of instrumentation will be deployed to investigate bottom boundary layer fluid-sediment interactions within the active surf zone. At each location, vertical profiles of horizontal velocities and suspended sediment, in addition to sea surface fluctuations will be recorded continuously (16Hz sampling rate) for the duration of the high energy portion of the experiment.
Funding is provided by the Coastal Sciences Program of the Office of Naval Research, Dr. T. Kinder, Program Manager.
Tom Drake Dept of Marine, Earth and Atmospheric Sciences 1125 Jordan Hall, NCSU Box 8208 Raleigh, NC 27695-8208 PH: (919) 515-7838 FAX: (919) 515-7802 INTERNET: drake@ncsu.edu |
Steve Snyder Dept of Marine, Earth and Atmospheric Sciences 1125 Jordan Hall, NCSU Box 8208 Raleigh, NC 27695-8208 PH: (919) 515-7912 FAX: (919) 515-7802 INTERNET: stephen_snyder@ncsu.edu |
We will use digital side-scan sonar equipment to map nearshore morphology and estimate surficial sediment size in the vicinity of Duck, North Carolina. We will also use high-resolution seismic mapping to determine areas in which sediment supply is limited; these so-called hardbottom areas are outcrops of cohesive or lithified substrate on the shoreface. They exert a controlling influence on the gross nearshore morphology of the N.C. barrier islands, but their presence and effect on sediment transport processes has not been incorporated into any models for nearshore sediment transport processes and the resultant nearshore morphology.
Digital side-scan sonar and high-resolution seismic mapping will use a four-wheel drive amphibious truck (LARC) from the Army Coastal Engineering Research Center's Field Research Facility (FRF) to obtain kilometers-long images of surfzone and nearshore bathymetry including the Duck94 and SandyDuck field experiment areas at the FRF. Our measurements will provide an expanded context for SandyDuck and future nearshore experiments at the FRF; conversely, the long-term record of bathymetry and wave climate at the FRF argues strongly for it as the main field site. Surveys extending several kilometers on either side of the FRF will be conducted a minimum of four times each year. Additional surveys of selected areas will be performed after storms and for bed perturbation studies.
We plan specifically to avoid the FRF during Sandy Duck. Our data will primarily address longer-term morphological questions of order (months/years). We would like to map the SandyDuck area immediately before instruments are deployed and again immediately after instrument retrieval. We will require the LARC and FRF personnel for approximately one 8-hr day per mapping survey.
We have submitted a full 3-year proposal to Dr. Russell Harmon, ARO to begin mid-FY96, and are seeking additional funding sources. We hope to know our ARO funding status by mid-fall 1996.
TITLE: SURFZONE WAVES, CURRENTS, AND MORPHOLOGY
Steve Elgar Electrical Engineering and Computer Science Washington State University Pullman, WA 99164-2752 PH: (509) 335-6602 FAX: (509) 335-3818 INTERNET: elgar@eecs.wsu.edu |
Thomas H. C. Herbers Department of Oceanography Naval Postgraduate School Building 232 Spanagel Hall, Room 342C 833 Dryer Road Monterey, California 93943-5000 PH: (408) 656-2917 (Office) / (408) 656-2673 (Department) FAX: (408) 656-2712 INTERNET: herbers@oc.nps.navy.mil |
William C. O'Reilly 412A O'Brien Hall University of California, Berkeley Berkeley, CA 94720 PH: (510) 642-6776 (office) FAX: (510) 643-8934 (fax) INTERNET: bor@coast.ucsd.edu |
R.T. Guza Center for Coastal Studies Scripps Institution of Oceanography 9500 Gilman Dr. La Jolla, CA 92093-0209 PH: (619) 534-0585 (office) FAX: (619) 534-0300 INTERNET: rguza@ucsd.edu |
The long-term goal is to understand the interactions between complex and changing bathymetry,
waves, and the quasi-steady nearshore circulation. Specific goals for the SandyDuck experiment
include observing and modeling in the nearshore and surfzone:
- the evolution of directionally-spread swell and sea
- the near-bottom, quasi-steady circulation
- the evolution of bar-scale morphology
- the mean water level across the surfzone and within the foreshore
Colocated sonar altimeters (33), pressure gages (69), and velocity sensors (33) will be deployed in a 2D grid, 200 (longshore) X 420 (cross-shore) m extending from about 1 to 5 m water depth (see figure). The array will encompass the region of strongest bar motion and morphological change and is large enough to include a significant bathymetric inhomogeneity (based on Duck94 bathymtery) so that effects of irregular bathymetry on waves and circulation can be investigated. The array is also long enough to resolve directional properties of incident, infragravity, and shear waves (based on SuperDuck and Delilah results). 'Compact' arrays of PUV gages embedded in the main cross-shore transect provide independent estimates of wave direction and may resolve narrow rip currents and the (high) wavenumbers of bar-intensified edge waves at incident wave frequencies. The mean water level will be measured with a single cross-shore array of buried pressure sensors.
Funded by ONR.
A plan view of the array is in the figure below. Sensor types, indicated in the legend, are P = pressure, SPUV = colocated sonar altimeter (S), pressure gage (P), and biaxial electromagnetic flowmeter (UV), PUV = pressure gage and flowmeter, X = buried Paros pressure gage.
TITLE: SHALLOW WATER WAVE AND SURF GENERATED AMBIENT NOISE
Josette Paquin Fabre Neptune Sciences, Inc. 150 Cleveland Ave. Slidell, LA 70458 PH: (504) 649-7252 FAX: (504) 649-9679 INTERNET: josie@neptunesci.com |
James H. Wilson Neptune Sciences, Inc. P.O. Box 1235 San Clemente, CA 92123 PH: (714) 366-6554 FAX: (714) 492-6820 INTERNET: wilson@vsinc.com |
There are three scientific objectives of this experiment. The objective of the experiment conducted during DUCK94 was to obtain ambient noise data at offshore positions from outside the surf zone to 7 km offshore (see figure for buoy locations). The first objective of the SandyDuck Wave and Surf Generated Ambient Noise experiment is to use sensors similar to those used in DUCK94 to obtain the components of the noise due not only to surf, but also to the waves breaking directly above the sensor. The second objective is to measure the coherence of individual wave events. The third objective is to acoustically differentiate between four different types of breaking waves (plunging, spilling, etc.)
Four "A" size sonobuoys with anchors and floats will be deployed by boat or helicopter at the locations indicated in the figure (depending on wind and wave conditions). Buoys will be retrieved by boat under good weather conditions. A RF antenna will me mounted on the tower and a trailer will be positioned under the tower with (coax) cable runing from the antenna (on the tower) to the trailer.
Deployment: as needed (from helo or boat), Operation: One preliminary test in july - sept, intensive 22 Sept to 28 Oct, selected with respect to weather conditions. Retrieval: Offshore buoys will be retrieved by boat or helo as soon as possible after they have died (they last 8 hours).
Carl Friedrichs Virginia Institute of Marine Science College of William and Mary Gloucester Point, VA 23062-1346 PH: 804-642-7303 FAX: 804-642-7195 INTERNET: cfried@vims.edu |
Don Wright Virginia Institute of Marine Science College of William and Mary Glouchester Point, VA 23062-1346 PH: 804-642-7103 FAX: 804-642-7195 INTERNET: wright@vims.edu |
John Brubaker Virginia Institute of Marine Science College of William and Mary Glouchester Point, VA 23062-1346 PH: 804-642-7222 FAX: 804-642-7195 INTERNET: brubaker@vims.edu |
Chris Vincent School of Environmental Sciences University of East Anglia Norwich NR4 7TJ, UK PH: +44 1603 592529 FAX: +44 1603 507719 INTERNET: C.Vincent@uea.ac.uk |
This study will observationally and theoretically examine sediment suspension, fluid movement,
and sediment transport across the lower shoreface (h = 8 - 20 m). The shoreface is the pathway
for exchange of fluid and sediment between the surf-zone and the shelf, and physical
understanding of long term erosion or deposition in either environment requires an understanding
of processes in this transition zone. Specific motivation for improved analytic models and
observations of cross-shore suspended sediment transport is provided by extreme inconsistencies
in predictions of net transport by commonly applied models and limitations in the ability of
typically deployed instrumentation to accurately represent suspended sand transport over the
lower shoreface.
In this investigation new analytic models for cross-shoreface sediment and fluid motion will be
developed which better recognize the simultaneous contributions of wave and wind forcing.
Deployments of acoustic instrumentation more capable of accurately quantifying cross-shore
sediment and fluid motion are planned. Analysis of these data will better constrain analytic
models by providing insight into such issues as: the nature of eddy diffusivity and viscosity;
orbital phase-dependent sediment concentration; wind- and wave-forced cross-shore mean
currents; and cross-shore suspended sediment transport as a function of along-shore current
strength, relative roughness, wave period and grain-size.
Two instrumented benthic boundary layer tripods, each based around a stainless steel frame 2.5 m high and 3 m across at the base, will be deployed on the lower shoreface. We plan to come in from the ocean side using a UNOLS research vessel; all power will be internal and all data internally recorded. We plan to deploy for a month in the summer season near the beginning SANDYDUCK and again for a month in the fall season near the end of SANDYDUCK.
Deployment by a UNOLS research vessel near the end of July 1997; operation until retrieval by a UNOLS vessel near the end of August 1997; redeployment by a UNOLS vessel near the end of September 1997; operation until retrieval by a UNOLS vessel near the end of October 1997.
Funding is provided by the National Science Foundation, Oceanography Division, Jointly between the Marine Geology & Geophysics Program and the Physical Oceanography Program, NSF Grant No. OCE-9504198. We are interested in sharing ship time with others to increase our time available for CTD and ADCP transects.
VIMS benthic boundary layer tripods typically support 5 Marsh-McBirney electromagnetic
current meters and 5 Downing optical backscatter sensors at 0.1, 0.4, 0.7, 1.0 m and 1.3 m above
the base; a Paroscientific pressure sensor at 2.5 m; and a thermistor at 0.7 m. To supplement this
standard tripod configuration at SANDYDUCK, sand concentration will also be measured at
each tripod using vertically profiling acoustic backscatter sensors. In addition, all three velocity
components plus acoustic backscatter will be provided at each tripod by one or two Sontek
acoustic Doppler velocimeters mounted near the bed. More complete density information will be
provided by the addition of salinity sensors. Finally, velocity throughout the watercolumn will
be measured at each pod site by an acoustic Doppler current profiler deployed in an upward
looking mode. The water depths will be about 8 m and 12 m for the lower energy summer
deployment, and about 12 m and 20 m for the higher energy fall deployment. Precise
deployment locations will be determined via coordination with Peter Howd and Kent Hathaway
who are also investigating shoreface processes.
TITLE: VERTICAL STRUCTURE, BEDFORMS, AND TURBULENCE
John W. Haines 600 4th St. S St. Petersburg, FL 33710 PH: (813) 893-3100 x3022 FAX: (813) 893-3333 INTERNET: jhaines@wayback.er.usgs.gov |
Guy Gelfenbaum 600 4th St S St. Petersburg, FL 33710 PH: (813) 893-3100 x3017 FAX: (813)893-3333 INTERNET: ggelfenbaum@wayback.er.usgs.gov |
Our objectives are to make observations to test existing models of the vertical structure of mean currents within and outside of the surf-zone. In particular we intend to address 1) the temporal and vertical variability in the turbulent flow field 2) the potential for surface enhancement of mean flows and turbulent fluctuations associated with breaking waves 3) the evolution of sedimentary bedforms and the influence on turbulence generation and parameterizations of bed roughness. Our primary approach is to deploy a vertical stack of Acoustic Doppler velocimeters while making simultaneous observations of breaking waves (Video monitoring with Tom Lippman) and bedform development (rotary side-scan, with Alex Hay, Doug Willson).
A vertical stack of Acoustic Doppler velocimeters will be deployed outside the primary bar (wherever that might be) in 3-4m water depth. A supplementary deployment in close proximity will provide a platform for rotary and pencil-beam sidescan deployment. Ancillary instrumentation will include pressure, speed of sound, and potentially suspended sediment (Acoustic). An in situ data acquisition system will be networked (fiber optic) to acquisition control and storage on the beach. The possibility exists that we may be able to enhance cross-shore coverage with the deployment of 1-2 ADCPs in intermediate depths. This would allow secondary focus on role of wind-forced flows.
We intend to sample continuously following deployment. Ideally we plan to deploy prior to the intensive sampling period, and maintain equipment throughout.
USGS internal funding awarded.
Primary - 8 SonTek Acoustic Doppler Velocimeters, 8 Compass/Tiltmeter Packages, 2 Pressure
sensors, 2 Speed of sound sensors, 1 Rotary Sidescan Sensor, 1 Acoustic Altimeter
Secondary (possibly, hopefully) - 2-3 Marsh-McBirney EM's, 2-3 Pressure Sensors, 1 Pencil
Beam Acoustic Sounder, 1 Acoustic Altimeter, 1-2 ADCP's
Instruments would be deployed on cross-shore transect along with Hay, Bowen, and Beach. Exact location to be determined in relation to these efforts. Depth limitations require Primary stack to be in 3-4m of water minimum. Research interests would ideally locate stack on outer flank of bar (or deeper). Secondary instrumentation (PUV, ADCPs) would be utilized to fill-in cross-shore transect.
Click here to view layout of Beach, Hanes, Hay/Bowen, and Thornton/Stanton.
Meredith A. Haines Dept of Marine Science University of South Florida 140 7th Ave South St. Petersburg, FL 33701 PH: (813) 893-9625 FAX: (813) 893-9189 INTERNET: meredith@marine.usf.edu |
David Fries Center for Ocean Technology University of South Florida 140 7th Ave South St. Petersburg, FL 33701 PH: (813) 553-3961 FAX (813) 553-3967 INTERNET: dfries@marine.usf.edu |
Robert Byrne Dept of Marine Science University of South Florida 140 7th Ave South St. Petersburg, FL 33701 PH: (813) 893-9508 FAX: (813) 893-9189 INTERNET: rbyrne@marine.usf.edu |
Parametrizations of gas exchange under energetic conditions with wave-breaking will be explored in this project. Woolf and Thorpe (1991) suggest that the widely used gas exchange formulation should be modified to include a factor for the departure from equilibrium that dissolved injected bubbles support. The consequences of finding the modified equation to be an improved description of the real world would include a reassessment of the regions of the ocean considered sources or sinks of, in particular, the less soluble gases such as oxygen.
This project will address the question of how to modify the traditional air-sea gas flux equation for specific gases by collecting field data for a range of gases under conditions of bubble injection. Dissolved gases will be measured in response to physical forcings in the nearshore environment during a multi-agency sponsored field experiment, SandyDuck'97. Total dissolved gas will be measured in situ and discrete samples will be collected for specific gas analyses on a field-portable mass spectrometer. Measurements made by other SandyDuck investigators will provide comprehensive coverage of the important physical forcings, allowing exploration of a range of alternate parametrizations. The data will be the first of its type collected in the nearshore, and of a wider scope than most open ocean experiments, except perhaps the recent CoOP efforts, in the range of gases and supporting measurements that will be collected.
Deployment of instrumentation will be from the Pier adjacent to the huts at the end. A CTD-GTD package will be deployed at mid-water depth (3-5m). The sensors will be monitored continuously in real-time from the NDBS hut. Water samples will be collected using a nisken-type sampler and analysed on site in the NDBS hut. Power supply/data logging will be managed from the Pier. A pressure sensor will also be deployed - strapped to the CTD-GTD. In addition Ming-Yang Su will provide a void fraction meter for deployment on the same structure.
Deployment before intensive period. Data collection through several storm events during the intensive period. Operation: Daily sampling, with night time sampling occasionally. Retrieval: On or before Nov 1.
In process of submission to NSF this month; may know by November.
Instruments to be deployed: Gas Tension Device (based on simple pressure sensor), CTD/O2 Void Fraction Meter, Pressure sensor, Nisken bottles
From Pier (ideally at end) at mid-water depth (3-5m).
TITLE: NEAR BED INTERMITTENT SUSPENSION
Daniel M. Hanes University of Florida Department of Coastal and Oceanographic Engineering P.O. Box 116590 Gainesville, FL 32611 PH: (352) 392-9801 FAX: (352) 392-3466 INTERNET: hanes@coastal.ufl.edu GRADUATE STUDENTS: Craig Conner, Chris Jette, and Eric Thosteson. |
Chris Vincent Internet: C.Vincent@uea.ac.uk |
The phenomena under investigation are the interactions between fluid and sediment near the seabed in regions significantly influenced by surface gravity waves. The emphasis of this research program is on the interactions resulting in momentum and energy transfer between fluid and grains near the seabed, and the influence of those interactions upon the local transport of sediment. The ultimate objective is to develop the capability to model, predict, and control coastal sediment transport and associated bathymetric change. Achievement of this objective will require significant improvement of our understanding of the physical interactions between fluid and grains near the seabed, as well as the development of models derived from our understanding of the relevant physical processes. These measurements also provide a useful tool for determining the accuracy of theoretical models of the time averaged concentration profile and time averaged suspended sediment flux.
Our field observations will focus on measurement of the small scale sediment processes, with emphasis on the measurement of suspended sediment concentration, and bedform geometry. An instrument array consisting of an acoustic concentration profiler, pressure sensor, acoustic doppler velocimeter, underwater video camera, rotating side scan sonar, multiple transducer array, and a data acquisition package will be deployed in approximately 4 meters water depth (see layout figure). A similar array of instruments will also be deployed off of the FRF pier using the SIS at a variety of cross-shore locations between depths of approximately 1 meter and 6 meters. The anticipated data will allow for the examination of wave and current induced sediment suspension processes over a variety of time scales ranging from approximately one second to hourly. The influence of bedforms upon the local suspension of sand will be the focus of some of the experiments. In particular, we hope to document the transition from a rippled bed to plane bed conditions, and the effects of this transition upon the associated suspended sediment field.
Funding for this study is being provided by the Coastal Sciences Program, ONR.
Richard M. Heitmeyer Code 7120, Naval Research Laboratory Washington DC. 20375-5320 PH: (202)404-8150 FAX: (202)404-7813 INTERNET: heit@wave.nrl.navy.mil |
The surf-noise component of the Sandyduck experiment is intended to provide the experimental
basis for the development of a quantitative model for describing the space- time properties of
surf-generated noise. The scientific objectives of the experiment are three-fold:
Obtain measurements suitable for: 1. identifying the dominant sound-generation mechanisms
(e.g., oscillations of bubbles generated in breaking waves, momentum transfer at the air-sea
and the water-sediment interfaces during wave breaking, etc.) 2. determining an acoustic source
model that represents those mechanisms in terms of observable parameters of the underlying
physical processes. 3. determining the impact of the acoustic environment (sound speed,
bathymetry, geoacoustic parameters) on the propagation of the surf-generated noise to regions
outside of the surf-zone. To achieve these objectives, systems will be deployed to measure:
a. the surface characteristics of individual breaking waves within a control volume (space-time
occurrences and size). b the acoustic time-frequency radiation pattern of the sound generated by
the individual breaking waves within that control volume. c the surf noise contribution generated
from within the control volume and by the total breaking wave field. d the broadband acoustic
propagation characteristics from the control volume.
The results of these measurements, together with those from other SANDYDUCK experiments
(e.g. surf strength dependence on bottom morphology, wave-height directional spectra, etc.) will
be used to establish the physical parameters for the surf noise model.
The four measurement systems identified in the science statement (2 a-d) and described in item (7 a-d) will be provided by NRL and deployed under the guidance and with the assistance of the FRF prior to the intensive experiments period. Two of those systems (b,d) will be deployed in the surf zone within cable length of the pier. System (c) will have one component (a hydrophone array) deployed outside of the surf-zone but also within cable length of the pier. Data on these systems will be acquired over a three week period during both daytime and nighttime hours with specific acquisition periods selected to provide a statistically significant sample over a full range of surf conditions. NRL will provide two 8x8 foot huts to house the on-shore electronics and monitoring components of these system. Additional trailer space is requested to house the off-line processing functions which will be used to assess data quality and to guide the selection of the specific data acquisition periods. NRL will assume full responsibility for the operation of the measurement systems.
Approximately a 27 day period: Deployment: 3 days, Operation: 21 days, Retrieval: 3 days
It is requested that the 21 day Operations Period be selected to provide an overlap with other
Sandyduck experiments intended to measure surf properties and to maximize the apriori
probability of high surf conditions. The total operations period can be split into two periods if
this is helpful to the overall Sandyduck scheduling. Full range of energy conditions desired.
Funded by Naval Research Laboratory 6.1 and 6.2 Base Research Programs.
The instruments to be deployed for the four measurement systems are: (a) Breaking wave characteristics.- two video cameras mounted on masts on the pier.(b) Acoustic radiation pattern. - a 30 m, 15 element, linear hydrophone/geophone array and associated power, cable, processing and recording systems. (c) Surf noise characteristics: - a 40 m, 64 element, linear hydrophone array and associated power, cable, processing and recording systems. - three DIFAR sonobouys and associated power, telemetry, processing and recording systems. (d) Acoustic propagation characteristics: - a broadband acoustic source (J11) and associated power, cable and signal generation systems.
The systems are deployed along a line orthogonal to the shore and about 250 m north of the pier as shown in the accompanying figure. The control volume, shown as the rectangular box in the Figure, has a bottom footprint of about 30 x 3 meters and is located at the nominal surf line. This volume contains the acoustic source and the hydrophone array, both of which are cabled to shore. The near-shore hydrophone array is located about 350 m from the control volume and is cabled to the pier. The three DIFAR buoys, shown at the bottom of the figure, are at ranges of about 1, 3, and 5 km. Finally, the two video cameras are mounted on the pier at the positions shown. The two acoustic arrays - cabled to shore with up to 250 m of 1/2 " double-armored cable for each array- acoustic source - cabled to shore with up to 250 m of 1/2 " double-armored cable. - video cameras - mounted on masts located on the pier and cabled to NRL huts. - DIFAR buoys - RF linked to shore-based receiver site.
TITLE: WAVE PROPAGATION ACROSS THE CONTINENTAL SHELF
Thomas H. C. Herbers Dept. of Oceanography Code OC/He Naval Postgraduate School Monterey, California 93943-5123 PH: (408) 656-2917 FAX: (408) 656-2712 INTERNET: herbers@kust.oc.nps.navy.mil |
William C. O'Reilly 412A O'Brien Hall University of California, Berkeley Berkeley, CA 94720 PH: (510) 642-6776 FAX: (510) 643-8934 INTERNET: bor@coast.ucsd.edu |
R.T. Guza Center for Coastal Studies Scripps Institution of Oceanography 9500 Gilman Dr. La Jolla, CA 92093-0209 PH: (619) 534-0585 FAX: (619) 534-0300 INTERNET: rguza@ucsd.edu |
The long-term goal of our research is to understand the physical processes affecting surface gravity waves on the continental shelf. Specific goals for the SandyDuck experiment include: - determine the effects of nonlinear wave-wave interactions on shoaling waves- evaluate the effects of complex bathymetry on the propagation and trapping of long waves - estimate wave energy losses owing to wave breaking and bottom friction
Approximately 12 battery powered, internal-recording pressure sensors and a directional wave buoy (with a radio-link to the FRF) will be deployed on the inner shelf directly offshore of the FRF in depths ranging from about 10- to 20-m. Additionally, 3 directional wave buoys (with Argos data transmission) will be deployed at mid- and outer-shelf (25-200 m depth) locations. These measurements will provide estimates of the evolution of wave frequency- and directional-spectra across the shelf.
Deployment 10-18 July (from R/V Cape Hatteras), Operation 18 July-20 September, Turnaround 20-27 September (from shore), Operation 27 September-2 December, Retrieval 2-13 December (from R/V Cape Hatteras)
This experiment is partially funded by the ONR Coastal Dynamics program and through ONR Durip grants. We just submitted a proposal for additional funding to the new ONR Shoaling Surface Waves DRI (funding decisions are expected in October).
Approximately 12 pressure sensors and 4 directional wave buoys
Three directional wave buoys are planned in nominally 200- (36 11 N, 74 48 W), 35- (36 11 N,
75 15 W), and 25-m depth (36 11 N, 75 34 W). An array of 9 pressure sensors (aperture
approximately 1 km) and a directional wave buoy will be deployed at 36 12.0 N, 75 42.3 W (in
about 20 m depth, 5 km offshore of the FRF). A cross-shore transect of 3 approximately equally
spaced pressure sensors (nominal depths 17-, 15- and 13-m) will span the region between the
20-m array and the FRF 8-m array. Wave measurements closer to shore (SPUV array) are
described in the Elgar/Herbers/O'Reilly/Guza questionnaire. Click here for more information about this experiment
TITLE: SWASH ZONE MORPHOLOGY
Todd Holland NRL Code 7442 Building 2437 Stennis Space Center, MS 39529 PH: (601) 688-5320 FAX: (601) 688-4476 INTERNET: tholland@nrlssc.navy.mil |
Abby Sallenger USGS Center for Coastal Geology 600 4th St. South St. Petersburg, FL 33701 PH: (813) 893-3100 x3002 FAX: (813) 893-333 INTERNET: abby@wayback.er.usgs.gov |
Our overall objective is to understand the evolution of 3D morphology in the foreshore region. We intend to quantify and monitor patterns of net sediment transport and swash characteristics over a longshore lengthscale of approximately 100 m(several cusp wavelengths). Our primary approach is to utilize multi-camera video techniques for both stereo analyses of morphology and determination of swash characteristics including maximum excursions and flow speeds. We expect to collaborate with Thornton, Turner, and other scientists interested in expanding our efforts to include in-situ instrumentation measurements of flow characteristics, sediment concentrations, and/or water table variations.
We intend to mount cameras on the FRF tower, near the dune line and possibly on the FRF pier overlooking a ~100m section of foreshore to the north side of the pier. Two overlapping study regions will be designed. Relatively coarse, but frequent measurements will be made in the larger region centered almost directly offshore (slightly north) of the FRF tower and extending approximately 50 m in each direction. Additional (no more than four) temporary towers near the dune line will be installed to suppliment the coverage and more throughly resolve the smaller 30x30 m subregion. These video-based foreshore surveys will occur round the clock (we plan to install lights on a tower). A small number of ground truth surveys and sediment samples will also be collected. We intend to be operatational during the six week "Intensive Experiment" period, with most frequent sampling around spring tides and storms.
US Geological Survey and Naval Research Laboratory
Rob Holman COAS, Oregon State University, 104 Ocean Bldg Corvallis, OR, 97331-5503 PH: (541) 737-2914 FAX: (541) 737-2064 INTERNET: holman@oce.orst.edu |
The overall objective of this work is to understand the dynamics of the fluid field over shoaling,
complex bathymetry and the response of that bathymetry to those fluid motions
Our principle science goal is to provide a larger-scale context for the intensive experiment area.
In space, we will ideally be able to sample morphology (by timex) over a 5 km region centered
on the pier, and foreshore bathymetry (by Argo) over a 2 km region centered on the pier. In time,
the intensive period of field work will be the culmination of a nested program that includes
analysis of the previous decade of Argus images and a three-month daily sampling of foreshore
beach profiles from August-October, 1996.
To supplement in-situ instruments and to ground truth some of our video techniques, we also
plan to collect extensive time stack and pixel time series video data over a superset of the
intensive in-situ region.
Video data collection will be based on a plethora of video cameras of appropriate focal length mounted on the FRF tower. These will feed as many image processors as are needed to provide time exposure areal coverage of the above area and pixel time series coverage of an appropriate number of locations. Dry beach profiles will be measured by phase-differential gps mounted on an amphibious ATV.
We can be fairly independent, but we will plan to cover at least the intensive period of sampling (end of Sept, through October). We can pull out independently.
Funded by ONR.
An array of video image processors and cameras to be deployed on the tower and a new south tower (to be cooperative with young Lippmann). Argo surveys are independent. Video coverage spans 2.5 km on either side of the pier, while Argo surveys will cover 1 km either side of the pier.
TITLE: GEOLOGIC SIGNATURE OF STORM EVENTS ON THE INNER CONTINENTAL SHELF AND OUTER
SURF ZONE
Peter Howd Duke University Marine Lab 135 Duke Marine Lab Rd, Beaufort, NC 28516 PH: (919) 504-7629 FAX (919) 504-7648 INTERNET: pahowd@acpub.duke.edu |
Rebecca Beavers Duke University Marine Lab 135 Duke Marine Lab Rd, Beaufort, NC 28516 PH: (919) 504-7631 FAX (919) 504-7648 INTERNET: rbeavers@acpub.duke.edu |
A cross-shore transect of surficial sediment samples, shallow (30 cm) box cores, and visual observations of bed morphology between depths of -4 to 14 m and covering a two year period will be combined with near continuous measurement of waves, currents and bed elevation at three locations (the Hathaway/Howd bipods at -5.5m, -8m and -13m) on the shoreface. These coupled records of sedimentary structures and processes will be used to test the hypothesis that there is a unique solution to the inverse problem of inferring flow conditions from preserved sedimentary strata in shoreface environments. Geologists commonly make this assumption in paleoclimatic reconstructions. Secondary objectives are to supplement shallower (surf zone) SandyDuck coring and sediment sampling experiments, and to provide larger scale continuity for investigators. This work began in the summer of 1996 and will constructively overlap the efforts of most geological/morphological investigators.
We have established three instrumented locations in 5m, 8m, and 13m depths for the period
spanning the DUCK94 and SandyDuck experiments. The locations support multiple (3) acoustic
Doppler current meters, a pressure sensor, and an acoustic altimeter. An upward looking broad
band ADCP is also located at the 13 m site.
A program of detailed boxcoring was initiated near each instrumented location in 1996. This
boxcoring will be expanded to include locations at meter increments of depth between 4 and 14
m depths during the summer of 1997. Some coring locations will consist of 2 orthogonal cores to
better define orientation of bedding structures. In other locations, arrays of multiple cores will be
used to define larger scale sedimentary structures. This program will extend into the summer and
fall of 1997 and will overlap with the SandyDuck Experiment.
Cores will be collected as sedimentation patterns and wave heights warrant and permit, repectively. Fair weather conditions during the summer allow for a large scale investigation which will be supplemented with boxcoring after storm conditions to investigate storm sedimentation patterns.
US Army Corps of Engineers, Coastal Research and Development Program
TITLE: GROUND PENETRATING RADAR OF THE BEACHFACE / SHOREFACE, SANDYDUCK EXPERIMENT
Harry M. Jol Department of Geography University of Wisconsin-Eau Claire 105 Garfield Street P.O. Box 4004 Eau Claire, WI 54702-4004 PH: (715) 836-3472 FAX: (715) 836-6027 INTERNET: jolhm@uwec.edu |
Ground penetrating radar (GPR) investigation of the beach and shoreface deposits. Two-dimensional and three-dimensional grid datasets will be collected to compare with offshore data. The preservation of depositional features is important in understanding what processes offshore are dominate in forming onshore deposits. The results will provide analogues to both oil and gas reservoir and hydrogeology models. A similar experiment was conducted in a high energy coastal area along the West Coast. A comparison would be valuable to look at differences and similarities in depositional patterns.
A portable, digital ground penetrating radar (GPR) system with a variety of antennae and transmitter powers will be used to survey the test site. Initially, test surveys at several locations will be conducted to test the feasibility of GPR at the site and decide on appropriate instrument configuration. Following the test phase, survey lines (parallel and perpendicular to the beach ) will be run. If a proper site can be located, a 3-D grid (25x25m or 50x50m) will be set-up and shot.
Will work around others. Preferably would like to shoot in July or August, during lower tides.
Unfunded - just transferred to new location and will know later this fall.
The surveys will taken on the beach above the high tide zone. The GPR system is very portable (backpack); thus we can work around others.
TITLE: OBSERVATIONS OF NEARSHORE WAVE BREAKING, WHITECAPPING, AND LARGE SCALE SAND BAR MORPHOLOGY
Tom Lippmann Center for Coastal Studies - 0209 Scripps Institution of Oceanography University of California, San Diego 9500 Gilman Dr. La Jolla, CA 92093-0209 PH: (619) 822-0605 FAX: (619) 534-0300 INTERNET: lippmann@coast.ucsd.edu |
1. Improved modeling of the spatial distribution of surface shear stress induced by wave breaking in the surf zone. (collaborative with Thornton and Stanton of NPS) 2. Examine the relationship between wave breaking, model predicted shear stresses and wave energy flux decay, and surface generated bubbles and turbulence. (collaborative with Thornton and Stanton of NPS) 3. Examine the temporal and spatial relationship of whitecaps to the local wave and wind field, and in particular examine the transition region of wave evolution between the inner shelf and surf zone. (collaborative with Herbers and O'Reilly of NPS) 4. Examine the behavior of sand bar morphology near the FRF on a daily basis over scales ranging from 1-5 km alongshore, and on a bi-monthly basis from Chesapeake Bay to Cape Hatteras over scales ranging 10-100 km. (collaborative with Holman of OSU, and Haines and Sallenger of USGS)
Measurements of wave breaking distributions (from 2 daylight and 1 intensified low-light video
cameras) will be examined continuously along cross-shore transects extending from the shoreline
to approximately 4-5 m depth, and located at several alongshore distances within the minigrid
area. Surf zone wave breaking observations will be used to calibrate a model for the wave stress
gradients. Additional wave energy transformation measurements (obtained by Elgar /Herbers
/O'Reilly /Guza and Thornton/Stanton along the same cross-shore transects) will be combined
with the breaking observations to give estimates of the cross-shore variation in set-up. The
model will be tested with set-up measurements from an array of manometer tubes (obtained by
Thornton and Stanton of NPS). The wave breaking observations (obtained from video cameras)
will also be made at the same location and coincident with collaborative (Thornton and Stanton
of NPS; Hay and Bowen of Dalhousie) measurements of the vertical distribution of void fraction
(air concentration from bubbles), turbulence (measured acoustically), ambient noise (from a
passive hydrophone), and sediment concentration profiles (also measured acoustically).
Whitecapping measurements will be made outside the surf zone, primarily from shipboard
mounted cameras during the deployment and retrieval of a bottom mounted wave directional
pressure array and several waverider buoys (deployed by Herbers and O'Reilly of NPS). Video
observations of the local whitecapping will be made in the vicinity of either free floating or
moored waverider buoys during the cruises.
Digital time-exposure images of the nearshore wave breaking patterns over a 5 km alongshore
range, centered around the FRF pier, will be obtained from northward and southward looking
video cameras mounted atop the 44 m high FRF tower and atop a 20 m high aluminum tower at
the southern end of the FRF property. Changes in the bathymetry will be inferred from the
average breaking patterns on a daily basis in the years prior to, during, and following the
andyDuck experiment. Additional very large scale morphology patterns from Chesapeake Bay to
Cape Hatteras will be inferred from time exposure images obtained from aerial over-flights
conducted on a bi-monthly basis beginning about 1 year prior to SandyDuck.
Deployments: October/November 1996:South Property Tower Set-up, mounting, and cabling Begin Aerial Overflights July 1997:Deploy video on FRF tower. Deploy GCP targets in surf zone and beach 1st Whitecapping Cruise (coordinated with Herbers) Nov/Dec 1997: 2nd Whitecapping Cruise (coordinated with Herbers) Operation: Large scale morphology: Oct 1996 - Oct 2096 SandyDuck wave breaking observations: 1 Aug - 31 Nov 1997 Whitecapping observations: July '97; Nov/Dec '97 Retrieval: SandyDuck video: November
Surf Zone Wavebreaking Funded (ONR); Whitecapping Funded (ONR); Large Scale Morphology Pending (USGS - Sept. 1996)
Video cameras mounted on the FRF tower near the top. Dune GCP's deployed temporarily or out of major traffic areas. The GCP's on jetted pipes in the surf zone can be positioned to avoid interference with instrumented arrays and CRAB/Sled profile lines. The 20 m high south tower will be located approximately 50-100 m north of the FRF south property line on the dune crest. Power and video cables to the FRF building will be deployed about 1 year prior to SandyDuck and coordinated with Bichner of the FRF.
TITLE: DIRECTIONAL WAVE OBSERVATIONS
C. E. Long USACE/WES/CERC Field Research Facility 1261 Duck Road Kitty Hawk NC 27949-4472 PH: (919) 261-3511 FAX: (919) 261-4432 INTERNET: long@duck.wes.army.mil |
I will make regular observations of wind wave frequency-direction spectra in the vicinity of the 8-m depth contour to serve as background information for other SandyDuck investigations. Historically, such observations have been useful for climatological purposes, detailing the nature of the ambient wind wave field, serving as control or boundary conditions in the execution and testing of dynamic models, and as one kind of ground truth for various alternative directional wave measurement schemes.
Data from an extant 15-element spatial array of near-bottom pressure gauges will be used to estimate wind wave frequency-direction spectra. Raw data will be collected and archived on the Field Research Facility (FRF) VAX computer, and can be made available to any SandyDuck PI. Spectra will be processed and archived in unformatted form on a Sun workstation. Spectra in formatted form will be placed in an ftp directory for access by SandyDuck PI's. Images of (some) spectra will be placed on the FRF home page.
Existing array will be maintained. Raw pressure data will be collected at 2 Hz for 2 hr 50 min 40 sec at 3-hr intervals coinciding with FRF collection times. Existing array will be kept after the experiment.
Funding source is Coastal Navigation Hydrodynamics Program of the U. S. Army Engineer Waterways Experiment Station Coastal Engineering Research Center. Tentatively approved funding is sufficient for the main experiment time frame. Final funding approval should be known by end of calendar year 1996.
System is extant.
TITLE: SEDIMENT TRANSPORT RATES DURING STORMS
Carl Miller Field Research Facility 1261 Duck Road Kitty Hawk, NC 27949-4471 PH: (919)261-3511 FAX: 1-919-261-4432 INTERNET: h.miller@cerc.wes.army.mil |
Don Resio Coastal Engineering Research Center Halls Ferry Road Vicksburg, MS PH: 1-800-522-6937 (ext. 2018) FAX: 1-601-634-2055 INTERNET: d.resio@cerc.wes.army.mil |
The Corps of Engineers must be able to model longshore sediment transport. Knowledge of the
"bulk" transport rate and the distribution of longshore transport across the surf zone is
particularly important to the design of inlet stabilization, beach renourishment, dredging, and
most other coastal projects the Corps is asked to undertake. At present the "bulk" transport rate
is estimated using some verison of the CERC formula. These CERC-type relationships generally
do not predict the cross-shore distribution of longshore transport. The appropriate value of the
coefficients to use and the reliability of these formulations are still in question. This
investigation is intended to provide direct measurement of the cross-shore distribution of "bulk"
longshore transport during storms. This data, which generally was not available previously, will
be used to enhance the CERC-type formulation and provide the Corps an improved engineering
tool.
The objective of the investigation is to use the Sensor Insertion System (SIS) to make bulk
longshore transport measurements during storm conditions. The SIS is a diverless instrument
deployment system that can operate in up to 5.6m waves. It provides the capability for the
instrumentation to be repositioned both horizontally and vertically during a storm so the
measurement scheme can evolve with the profile changes.
Secondary objectives include documenting cross-shore sediment transport processes and profile
evolution during storms, attempting order of magnitude measurements of swash-zone longshore
transport rates, and bedload transport rates.
Around the time of high/low tide the SIS will be used to deploy an array of sediment
concentration sensors, electromagnetic current meters, pressure wave gauges, sonic altimeters for
determining the bottom position, a video cammera for documenting the breaker type and bore
passage. At nominally, 12 cross-shore locations, 512 sec records from all of the instruments will
be obtained. To document cross-shore processes and profile variation, the measurements will
be repeated throughout the day. To investigate swash processes, during a number of storms,
streamer sediment traps will be lowered into the swash to accumulate sand for a short time. In a
similar manor bedload transport will be sampled.
Funding for this investigation will come from Coastal Research and Development Program of the US Army Corps of Engineers.
12 OBS concentration sensors, 5 EMCM current meters, 1 FOBS concentration array, 1 VEMA array, 2 Sonars (300kHz & 1M Hz) bottom sensors, 1 underwater video camera
TITLE: OBSERVATIONS OF WAVES AND CURRENTS NEAR THE SURF ZONE
Dr. Jerome A. Smith 0213, UCSD La Jolla, CA 92093-0213 PH: (619)534-4229 FAX: (619)534-7132 INTERNET: jasmith@ucsd.edu |
A major objective of our program is to document horizontal circulation patterns quantitatively
within an area of order 200 m by 500 m adjacent to the surf zone, over times long enough to
experience several kinds of conditions. We propose to deploy our digitally beam-formed Doppler
sonar technology, or "secscan sonars" (not to be confused with another device developed by A.
Hay). With each of these, one can obtain sequences of images of one component of the velocity
field over a continuous sector 90 degrees wide by almost 500m in range. Two secscan sonars can
be positioned with horizontal fans intersecting, providing a two component, two dimensional
(horizontal) maps of velocity versus time. With the two secscan systems, operating near 195kHz
and 225kHz acoustic frequency, an area 200m by 500m is feasible, with roughly 5m resolution.
This should provide movies of the vertical component of vorticity within the region, for example.
Accurate pictures of the time evolution of individual "rip currents" would then become available
from a variety of circumstances, together with a description of the background flow. Relations
between the evolution of these fields and both the incident surface waves and the along-shore
flow would be sought. The secscan sonars will also resolve surface wave propagation over the
insonified area.
We plan to deploy two "Duck Landers," approximately 400 and 800m North of the pier and at about the 6.5m depth contour. The cables supplying power and information would run along this contour back to the end of the pier, and connect through a junction box there to our lab ashore. Each Lander will have one secscan sonar and array of pressure sensors, plus miscellaneous tilt, optical clarity, CTD, or similar. Each lander will have remote leveling and azimuthal control. The landers are expected to extend between 1 and 2 meters above the bottom, with 4 jetted-in legs in roughly a 2.5-m square configuration. Once installed, there should be little maintainance required (we hope!). We plan to bring 4 certified divers within our group.
Advance group arrives 15 JULY 1997 and establishes logistics and staging site. Remainder of group arrives 17 JULY. Assembly and test of landers, installation of pier junction box and cables to the end of the pier should take about 10 days. Helocopter launching of landers and connection to pier should take another 3 days. OPERATION Full operational test and calibration should take another 6 days. We hope to be running by Sept, and will run through the end of October and possibly into November. It should be possible to run continuously with 2 or 3 people onsite. An emphasis is placed on real-time display and interaction with the other participants. RETRIEVAL mid Nov 1997. Reinforcements will arrive sometime near 1Nov. and begin disassembly and retrieval of the equipment.
We are presently funded through the end of FY96. The proposal for FY97-8 has been sent, with some encouraging feedback so far.
Two "Duck Landers" (see above).
The landers are intended to be situated about 300 to 500 meters outside the "breakpoint"-- a nebulous term indicating the distance offshore where waves often break. We intend to image an area inshore of the landers, extending to and over some of the other instruments fielded-- in particular, we are interested in intersecting some of the vertical profiles of currents proposed to lie along some of the inshore transects.
Ming-Yang Su Naval Research Laboratory Code 7331 Stennis Space Center, MS 39529-5004 PH: (601) 688-5241 FAX: (601) 688-5997 INTERNET: su@nrlssc.navy.mil |
William Teague Naval Research Laboratory Code 7332 Stennis Space Center, MS 39529-5004 PH: (601) 688-4734 FAX: (601) 688-5997 INTERNET: teague@nrlssc.navy.mil |
NRL shall measure and model the spatial and temporal distributions of nearshore wave breaking, bubble size spectra, and void fraction within the water depth from about 8 m to 20 m under various sea states and weather conditions. Bubble size spectra and void fraction at each location will be made from near surface to a depth about 4 meters.
(i)For each water depth of 8, 10, 12, 16, and 20 m, linearly offshore (offshore distances from 0.8 to 4.5 km), a surface-following buoy of vertical length of about 4 m will be deployed and moored to the sea floor. On each buoy, a series of void fraction meters and acoustic sesonators for bubble size spectra, and accelerometers for wave heights will be mounted. (ii) A video camera mounted on the top of the FRF tower for observing near-shore breaking waves. (iii) A video-mounted helicopter will be flown over the line of buoy arrays (i) for about six times (approximately two hours each).
Void fraction meter - 0.0001 to 0.6 void fraction, Acoustic resonator - bubble radius from 30 to 1200, microns, and maximum void fraction of 0.0001, Accelerometer - on the moored bubble buoy for wave height.
Deployment: July - August, 1997, Operation: September - October, 1997, Retrieval: November, 1997
The proposal for this project has been approved by the Naval Research Laboratory for FY97-00.
See the attached Figures 1 and 2, and the previous statements in items (3) for NRL instrument array locations. The instruments will be on the north side of the pier (the SANDYDUCK test range).
Ib Svendsen Center for Applied Coastal Research, Department of Civil Engineering Univ. of Delaware Newark, DE 19716 PH: (302) 831-2449 FAX (302) 831-1228 INTERNET: ias@coastal.udel.edu |
Peter Howd Duke University Marine Lab 135 Marine Lab Rd, Beaufort, NC 28516 PH: (919) 504-7629 FAX (919) 504-7648 INTERNET: pahowd@acpub.duke.edu |
Jim Kirby Center for Applied Coastal Research, Department of Civil Engineering Univ. of Delaware Newark, DE 19716 PH: (302) 831-2438 FAX (302) 831-1228 INTERNET: kirby@coastal.udel.edu |
Ed Thornton Naval Postgraduate School Monterey, CA 93943 PH: (408) 656-2847 FAX (408) 656-2712 INTERNET: thornton@oc.nps.navy.mil |
The primary objective is to obtain field data appropriate for defining boundary conditions for
computational models of surf zone currents, to use the models to compute the flow in internal
part of the instrumented region, and, finally, compare the results of the computations with data
from that internal region.
The field portion of this work will be conducted North of the FRF Property. A cross-shore array
of 6 electromagnetic current meters and pressure sensors will be deployed from approximately
the -1 m depth contour to the -5 m depth contour. The array will serve to address spatial
homogeneity along the beach, as well as extend the longshore extent of the primary arrays
contained within the FRF property lines. Most importantly, the array will provide a lateral
boundary condition for modeling efforts. The offshore boundary will be provided by 8 m array
data collected by the FRF. It is hoped that the southern lateral boundary condition will result
from collaboration with other PIs.
The post-experiment modelling effort will consist of a combined application of the Boussinesq
short wave model and the SHORECIRC circulation model. The Boussinesq computations are
needed to establish the short wave forcing for the infragravity and circulation flows in the region.
Input for the Boussinesq model will come from the 8-m array and will be used for computation
with the Boussinesq model in a region that extends in the longshore direction beyond the limits
of the mini-grid. These computations will use bathymetric surveys made by the FRF in other
contexts. The outcome of these computations can be verified against the pressure gage results.
The computations will also provide infragravity wave forcing for the entire domain which
together with the data from the boundary array is used in the computations with SHORECIRC to
determine the current and infragravity wave motion in the region.
Unknown, ONR Planning letter submitted on or about 2/23/96. Negotiations underway.
TITLE: NEARSHORE WAVE AND SEDIMENT PROCESSES
Edward B. Thornton Oceanography Department Naval Postgraduate School Monterey, CA 93943-5000 PH:(408) 656-2847 FAX: (408) 656-2712 INTERNET: thornton@oc.nps.navy.mil |
Timothy P. Stanton Oceanography Department Naval Postgraduate School Monterey, CA 93943-5000 PH: (408) 656-3144 FAX: (408) 656-2712 INTERNET: stanton@oc.nps.navy.mil |
The long term goals are to predict the wave-induced three dimensional velocity field and induced sediment transport over arbitrary bathymetry in the near shore. Specific goals of the SandyDuck experiment include: -observe and model the vertical structures of 3-components of mean, wave-induced and turbulent velocities, sediment flux, and bubbles across the surf zone. -observe and model the small-scale morphology. -observe and model the cross-shore set-up/down and alongshore pressure gradients.
-Vertical structures of 3-components of mean, wave-induced and turbulent velocities, sediment
flux, and bubbles across the surf zone will be measured from a mobile sled. Instruments on
the sled include a vertical array of 8 em current meters, 8 void fraction sensors, 2 acoustic
resonators, 6 pressure sensor array to measure wave direction, vertical and horizontal arrays of 5
obs's, rotating pencil-beam acoustic altimeter and a Bistatic Coherent Doppler Velocity/Sediment
meter (BCDVS). The sled is to be deployed by the CRAB daily early in the morning offshore
of the bar. The sled is then towed sequentially shoreward using the four-wheel-drive fork lift
stopping at 5-8 cross-shore locations for at least one hour. The sled is to be deployed at longshore
line 935m (FRF coordinates) and can be deployed up to 150 m north of this location.
-A second BCDVS measuring 3-components of mean, wave-induced and turbulent velocities
along with sediment flux is to be mounted on a stationary frame within the trough of the surf
zone (collaboration with Hay and Bowen).
-A Coherent Acoustic Sediment Profiler to measure 3-components of mean, wave-induced and
turbulent velocities, and sediment flux is to be mounted on a stationary frame within the trough
of the surf zone (collaboration with White).
-Small-scale morphology will be measured in the mini-grid area during each CRAB survey using
an array of 7, 1MHz acoustic altimeters mounted on the CRAB to make area surveys. GPS
differential navigation is used for location and elevation and tilt, acceleration and rotational
acceleration are measured to correct for motion.
-Cross-shore variations of wave height and set-up/down and alongshore pressure gradients will
be measured using 3 cross-shore arrays composed of 8 pressure senors and 8-14 manometers
each located at alongshore distances 692, 788, 915 m relative to FRF coordinates, and an
alongshore array of 8 manometers located in the trough.
Deployment of manometer/pressure arrays 7-14 September. Instruments on CRAB are designed for quick attach/detachment. Operation: 15 September - 1 November, Retrieval: 1-3 November
This work is funded by the Office of Naval Research, Coastal Sciences.
Click here to view to layout of Beach, Haines, Hanes, Hay/Bowen, and Thornton/Stanton.
TITLE: EXPERIMENT TESTS OF BOUSSINESQ WAVE MODELS IN THE NEAR SHORE ZONE
Dennis Trizna Code 7255, NRL, 4555 Overlook Ave Washington, DC 20375 PH: (202) 404-7891 FAX: (202) 767-3303 INTERNET: triznad@ccf.nrl.navy.mil AND/OR triznad@onrhq.onr.navy.mil |
Steve Frasier MIRLS, Knowles Engineering Building Rm 113 University of Massachusetts Amherst, MA 01003 PH : (413) 545-4582 FAX: (413) 545-4652 INTERNET: frasier@alex.ecs.umass.edu |
James Kirby Center for Coastal Engineering Research University of Delaware Newark DE 19716 PH : (302) -831-2438 FAX: (320) -831-1228 INTERNET: kirby@coastal.udel.edu |
Boussinesq models of shallow water wave propagation into the surf zone and their ability to predict cross and along shore current flow is of interest to Naval littoral interests. Field testing and field validation of such models has been difficult because of the innability to establish boundary conditions for the input wave field. Along track interferrometric synthetic aperture radar (INSAR), flying along the coast and imaging cross-shore radial velocity components, allows one to image the surface radial velocities on scale sizes of the order of a meter pixel size that can provide data for model boundary conditions. Moreover, imaging radars onshore, such as FOPAIR (Focussed Phased Array Imaging Radar, ~100m by 64m view, 1-m pixel) and a marine radar (~1.5km radius image, 6-m pixel) can provide near shore wave field imagery against which to compare the results of numerically propagating the INSAR wave pattern using the Boussinesq model. The FOPAIR can produce wave images of both radar echo intensity (Normalized Radar Cross Section, NRCS) and radial velocity (Doppler) maps simultaneously at 5-Hz image rates, while the marine radar can provide NRCS maps over the larger area every 1.85s with a few minute continuous record. In this experiment we propose to test Boussinesq-like wave models with the new NRL INSAR, U. Mass. FOPAIR, and an NRL digital imaging marine radar.
The shore based imaging radars will be mounted on the Navy experiment van near the end of the pier (FOPAIR), on the pier-end tower, and atop the FRF laboratory building. Pier radars data acquisition computers will be located in the pier-end hut, while the marine radar acquisition system will be located in the FRF computer room. The NRL UltraWideband SAR (NUWSAR) will be flown on the NRL P3 for an unspecified number of days across the area. Univerisity of Delaware personel will run the Boussinesq model using an as yet unspecified Cray-level computer using data collected, but will not require FRF facilities.
FOPAIR deployment will take up to 3 days, with installation of a hut roof platform to hold the FOPAIR radar antenna. The installation will occur so as to minimize the need for FRF personnel, and can take place relatively far in advance of the main experiment. Collection will occur during the main experiment with some testing prior to it after deployment.
Funding for the proposal is pending.
TITLE: MARINE RADAR REMOTE SENSING OF BAR AND RIP MORPHOLOGY
Dennis Trizna Code 7255, NRL, 4555 Overlook Ave Washington, DC 20375 PH: (202) 404-7891 FAX: (202) 767-3303 INTERNET: triznad@ccf.nrl.navy.mil AND/OR triznad@onrhq.onr.navy.mil |
Suitable averaging of marine radar imagery collected over one minute, with collection time intervals on time scales of five minutes have shows what appears to be the occurrence of near shore rip structures inside the offshore bar. The sensing of such current features using a radar intensity measure holds promise for Naval littoral operations using standard onboard radars. To validate the hypothesis that the observed surface effects are indeed due to enhanced wave-current interactions over a current rip, we plan to collect radar imagery for comparison with the acoustic Doppler imaging system to be deployed by Jerry Smith. A comparison of the location of the currents measured below the surface will be made with the radar estimate of the surface currents. With knowledge of the subsurface current magnitudes, an empirical estimate can be determined of the relationship between the current strength and the normalized radar cross section contrast of the sea surface region imaged over the rip relative to the ambient.
Operate a marine radar continuously during the Sandy Duck '97 experiment, with intense periods during the acoustic subsurface imaging system. During periods of strong along shore flow rip currents are expected. These have been observed in the past at the FRF, after flooding rains saturated the Chesapeake Bay basin and its outflow drains southward along shore. Mushroom vorticle structures were observed under such forcing. During strong wind wave forcing at oblique angles to the shoreline, linear rip currents are expected. Both types of events will be anticipated, and the conditions forcing them as described above will focus coordinated data collections by the acoustic and marine radar remote sensors. No special logistic support is needed, other than outine insitu collections that support the overall goals of SANDYDUCK.
Deployment will occur in conjunction with the main experiment for data comparisons, but collection will occur before and after the experiment.
Funded through ONR.
Marine radars currently in place on top of main building and on tower at end of pier. Acoustic sensors per Jerry Smith plan. Click here to view more about the Smith plan.
TITLE: QUANTIFYING RATES OF GROUNDWATER INFILTRATION / EXFILTRATION IN THE SWASH ZONE
Ian L. Turner Laboratory for Coastal Research, University of Maryland LeFrak Hall, College Park, MD 20742 PH: (301) 405-4060 FAX: (301) 314-9299 INTERNET: iturner@bss2.umd.edu |
The principal objective of the proposed experiment is to obtain field measurements of groundwater infiltration/exfiltration within the swash zone. The focus will be to quantify infiltration associated with single runup events, and to determine net groundwater exchange through the tidal cycle. Through this work we anticiapte the ability to begin to shed some light on the interaction of groundwater processes with sediment transporting mechanisms across the beach face.
Our pore-pressure equipment consists of two (or more?) vertical arrays of high-sensitivity, low-range pressure sensors, buried in the top 0.3 m of the beach face. All sensors are cabled to a single PC-based data aquisition system. A shore-normal transect of screened piezometers (OD approx. 50 mm) will also be installed across the intertidal, at a horizontal spacing of approximately 2.0 m. It is anticipated that repeated monitoring will be undertaken through several (not necessarily consecutive) tidal cycles.
We anticipate spending one to two weeks at the FRF, during the six week "intensive Experiment" period. At this stage our timing is flexible, and can be adjusted to coincide with possible collaborators (e.g. Thornton et al, Holland and Sallenger).
The Andrew W. Mellon Foundation. Confirmed.
Buried sensors + single (shore-normal) transect of piezometers at approximately 2.0 m
horizontal spacing across the intertidal profile. Deployment and configuration subject to
discussions with potential collaborators.
TITLE: BOUNDARY LAYER PROCESS
Thomas E. White USAE Waterways Experiment Station CEWES-CD-P 3909 Halls Ferry Road Vicksburg, MS 39180-6199 PH: 601-634-2052 FAX: 601-634-3151 INTERNET: t.white@cerc.wes.army.mil |
The objective of this effort is to improve our ability to measure and understand what is occurring in the boundary layer. Other investigators are focusing on measuring and modeling suspended-load sediment transport. This is largely because of the inadequacy of today's technology, yet a portion of the transport is missed. A complete description of the transport necessitates better measurements and analytical theories for boundary-layer processes.
Sediments. Measure boundary-layer processes by vertically profiling velocities and sediment
concentrations within the intense layer of transport between dimensionless volume
concentrations of 0.08 and 0.60, where present-day technology is inadequate, by: (a) deploying
Naval Postgraduate School's profiling flux sensor (with their cooperation), and (b) capturing and
calibrating the backscatter intensity information from Sontek's ADCM. The above
measurements will be supplemented with traditional OBS technology.
Fluids. Convert all boundary-layer measurements of currents from outdated electromagnetic
technology, which interferes with flow when placed within three probe diameters of the bed, with
acoustic Doppler technology. This was done on an experimental basis at one location at Duck94.
One platform of sensors will be deployed in the surfzone, requiring CRAB and Army-supplied dive team for pipe jetting on both deployment and retrieval. We will deploy during the indicated calendar dates for general deployment, but will retrieve during targets-of-opportunity in the schedule about two to three weeks after deployment.
Surfzone platform with vertical arrays of sensors: Coherent Acoustic Sediment Profiler,
Sontek Acoustic Doppler, three-pronged Doppler current meters, Optical backscatter sensors,
Pressure sensor, Electromagnetic current meters. In the bottom boundary layer: Coherent
Acoustic Sediment Profiler, Sontek Acoustic Doppler three-pronged Doppler current meter,
Optical backscatter sensor.
Instruments will be deployed in the active surfzone deeper than 2 meters,
but inside the breakers.
TITLE: NEARSHORE WATER LEVEL PROFILES DURING STORMS
Dr. C. S. Wu NWS/NOAA 1325 E-W Highway Silver Spring, MD 20910 PH: (301)-713-1613 FAX: (301)-713-0003 INTERNET: cswu@thunder.nws.noaa.gov |
Dr. H. H. Shih NOS/NOAA 1305 E-W Highway Silver Spring, MD 20910 PH: (301)-713-2864 FAX: (301) 713- 4465 INTERNET: shih@wlnet1.nos.noaa.gov |
Breaking wave induced coastal water level set-up during storm waves approaching the shore are
reported to have significant impact on the mean water level predictions. For the protection of
human life and properties in the coastal zone, tidal level and storm surges have been of national
concern. In recent Hurricane Opal'95, the wave heights near the landfall are found at the same
order as the surges, the total water level was the combined effects of waves and surges due to the
storm. For SandyDuck experiment (Oct. 1997), we propose to measure wave set-up profiles
along the FRF PIER.
The obtained water level data may be used as a reference during the experimental period. The
coupled data of water level and waves will benefit our understanding of nearshore process. The
field data of wave set-ups will be used to verify wave models which are to be integrated into the
operational storm surge model employed by the NOAA NWS.
NOAA National Ocean Service operate a water level monitoring station at the pier end. This include an air acoustic gauge (primary) and a pressure gauge (secondary). In addition to these, three more set of gauges will be deployed along the pier at 100m, 200m and 300 m from the shoreline (see the layout). Water levels will be sampled at 1 Hz rate. Data from gauges will be transmitted to a PC-based data logger via cables along the deck.
Schedule: (follows the SandyDuck experiment schedule, Sept-Nov '97)
Funding agency and status: NOAA, to be determined in Oct 1996.