TITLE: GPS SOUNDER

PERSONNEL INFORMATION


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.

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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 STATUS

Funding to support the measurements will be provided by ONR. At this time, the funding situation appears to be good.

INSTRUMENTS AND LOGISTICS

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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 STATUS

Funding is provided by the Coastal Sciences Program of the Office of Naval Research, Dr. T. Kinder, Program Manager.

LAYOUT PLAN

TITLE: SIDE-SCAN SONAR STUDIES OF NEARSHORE MORPHOLOGY IN THE VICINITY OF DUCK, NC

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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.

FUNDING STATUS

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.

INSTRUMENTS AND LOGISTICS

None.

TITLE: SURFZONE WAVES, CURRENTS, AND MORPHOLOGY

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

Deployment: 7-25 July (Early field crew to arrive about 20 June). Operation: 1 August-16 November Retrieval: 17-26 November

FUNDING STATUS

Funded by ONR.

INSTRUMENTS AND LOGISTICS

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVES

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.)

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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).

FUNDING STATUS

Minimal experiment funded.

INSTRUMENTS AND LOGISTICS

Sonobuoys (with temperature sensor) deployed by helicopter., CTD cast from pier periodically.

TITLE: CROSS-SHOREFACE SUSPENDED SEDIMENT TRANSPORT: A RESPONSE TO THE INTERSECTION OF NEARSHORE AND SHELF PROCESSES

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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 STATUS

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.

LAYOUT PLAN

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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).

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

We intend to sample continuously following deployment. Ideally we plan to deploy prior to the intensive sampling period, and maintain equipment throughout.

FUNDING STATUS

USGS internal funding awarded.

INSTRUMENTS AND LOGISTICS

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

LAYOUT PLAN

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.

TITLE: GASES FLUX MEASUREMENTS IN THE NEARSHORE AND PARAMETRIZATION UNDER ENERGETIC CONDITIONS

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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.

FUNDING STATUS

In process of submission to NSF this month; may know by November.

INSTRUMENTS AND LOGISTICS

Instruments to be deployed: Gas Tension Device (based on simple pressure sensor), CTD/O2 Void Fraction Meter, Pressure sensor, Nisken bottles

LAYOUT PLAN

From Pier (ideally at end) at mid-water depth (3-5m).

TITLE: NEAR BED INTERMITTENT SUSPENSION

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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 STATUS

Funding for this study is being provided by the Coastal Sciences Program, ONR.

LAYOUT PLAN

Click here to view the layout of Beach, Haines, Hanes, Hay/Bowen, and Thornton/Stanton.

TITLE: SURF-NOISE EXPERIMENT

PERSONNEL INFORMATION


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


SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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.

FUNDING STATUS

Funded by Naval Research Laboratory 6.1 and 6.2 Base Research Programs.

INSTRUMENTS AND LOGISTICS

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.

LAYOUT PLAN

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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)

FUNDING STATUS

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).

INSTRUMENTS AND LOGISTICS

Approximately 12 pressure sensors and 4 directional wave buoys

LAYOUT PLAN

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

FUNDING STATUS

US Geological Survey and Naval Research Laboratory

LAYOUT PLAN

TITLE: LARGE SCALE RESPONSE

PERSONNEL INFORMATION


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

SCIENCE STATEMENT

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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.

FUNDING STATUS

Funded by ONR.

INSTRUMENTS AND LOGISTICS

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE:

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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.

FUNDING STATUS

US Army Corps of Engineers, Coastal Research and Development Program

TITLE: GROUND PENETRATING RADAR OF THE BEACHFACE / SHOREFACE, SANDYDUCK EXPERIMENT

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVES

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

Will work around others. Preferably would like to shoot in July or August, during lower tides.

FUNDING STATUS

Unfunded - just transferred to new location and will know later this fall.

LAYOUT PLAN

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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)

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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

FUNDING STATUS

Surf Zone Wavebreaking Funded (ONR); Whitecapping Funded (ONR); Large Scale Morphology Pending (USGS - Sept. 1996)

LAYOUT PLAN

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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 STATUS

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.


INSTRUMENTS AND LOGISTICS

System is extant.

LAYOUT PLAN

TITLE: SEDIMENT TRANSPORT RATES DURING STORMS

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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 STATUS

Funding for this investigation will come from Coastal Research and Development Program of the US Army Corps of Engineers.

INSTRUMENTS AND LOGISTICS

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

PERSONNEL INFORMATION


Dr. Jerome A. Smith
0213, UCSD
La Jolla, CA 92093-0213
PH: (619)534-4229
FAX: (619)534-7132
INTERNET: jasmith@ucsd.edu

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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.

FUNDING STATUS

We are presently funded through the end of FY96. The proposal for FY97-8 has been sent, with some encouraging feedback so far.

INSTRUMENTS AND LOGISTICS

Two "Duck Landers" (see above).

LAYOUT PLAN

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.

TITLE: COASTAL BREAKING WAVE AND BUBBLE MEASUREMENTS

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

(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).

INSTRUMENTS AND LOGISTICS

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.

SCHEDULE

Deployment: July - August, 1997, Operation: September - October, 1997, Retrieval: November, 1997

FUNDING AGENCY AND STATUS

The proposal for this project has been approved by the Naval Research Laboratory for FY97-00.

LAYOUT PLAN

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).

TITLE: MODELS OF NEARSHORE CIRCULATION

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN


A cross-shore array of current and pressure sensors will be installed approximately 250 m north of the primary arrays (or about 1250 m in the FRF coordiante system) to measure advection into the model domain and provide a northern boundary condition for the dominant waves from the north quadrant.The cross-shore array will consist of 6 electromagnetic current meters and pressure sensors and will extend from approximately the -1m contour to the -5m contour. The current meters will be deployed so as to augment the northern end of the Elgar et al. longshore arrays (see their experiment plan), that is exact cross-shore distances will be chosen with consideration of their array design as well as needs of the model so as to maximize the utility of the additional data. Each will be individually cabled to shore for power and data logging. The data acquisition system will be referenced to a time standard with sufficient accuracy as to make this array a coherent extension of other investigators arrays located on the FRF property. Data collection will be essentially continuous at 8 Hz. Flow measurements representative of the water column (as opposed to boundary layer) are desired. The data loggers and power supplies will be located at a rental house immediately landward of the array location to avoid lengthy cable runs over a very popular tourist beach. This may impact the exact longshore location of the array to a small extent.

FUNDING STATUS

Unknown, ONR Planning letter submitted on or about 2/23/96. Negotiations underway.

TITLE: NEARSHORE WAVE AND SEDIMENT PROCESSES

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

-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.

PROPOSED SCHEDULE

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

FUNDING STATUS

This work is funded by the Office of Naval Research, Coastal Sciences.

LAYOUT PLAN

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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 STATUS

Funding for the proposal is pending.

INSTRUMENTS AND LOGISTICS

TITLE: MARINE RADAR REMOTE SENSING OF BAR AND RIP MORPHOLOGY

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

Deployment will occur in conjunction with the main experiment for data comparisons, but collection will occur before and after the experiment.

FUNDING STATUS

Funded through ONR.

INSTRUMENTS AND LOGISTICS

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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).

FUNDING STATUS

The Andrew W. Mellon Foundation. Confirmed.

LAYOUT PLAN

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

PERSONNEL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENT PLAN

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.

PROPOSED SCHEDULE

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.

FUNDING STATUS


USACE CERC's Coastal Program project "Coastal Sediment Transport Processes" Sponsors review plans on an annual basis. Sponsors are discussing whether boundary-layer measurements should be made on the FRF Sensor Insertion System, or on a separate platform.

LAYOUT PLAN

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

PERSONELL INFORMATION


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

SCIENTIFIC OBJECTIVE

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.

EXPERIMENTAL PLAN

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.

PROPOSED SCHEDULE

Schedule: (follows the SandyDuck experiment schedule, Sept-Nov '97)

FUNDING STATUS

Funding agency and status: NOAA, to be determined in Oct 1996.

LAYOUT PLAN