Frye Daniel E.

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Design and operation of automated ice-tethered profilers for real-time seawater observations in the polar oceans

(Woods Hole Oceanographic Institution, 2006-06) Krishfield, Richard A. ; Doherty, Kenneth W. ; Frye, Daniel E. ; Hammar, Terence R. ; Kemp, John N. ; Peters, Donald B. ; Proshutinsky, Andrey ; Toole, John M. ; von der Heydt, Keith

An automated, easily-deployed Ice-Tethered Profiler (ITP) has been developed for deployment on perennial sea ice in polar oceans to measure changes in upper ocean temperature and salinity in all seasons. The ITP system consists of three components: a surface instrument that sits atop an ice floe, a weighted, plastic-jacketed wire-rope tether of arbitrary length (up to 800 m) suspended from the surface instrument, and an instrumented underwater unit that profiles up and down the wire tether. The profiling underwater unit is similar in shape and dimension to an ARGO float except that the float's variable-buoyancy system is replaced with a traction drive unit. Deployment of ITPs may be conducted either from ice caps or icebreakers, utilizing a self contained tripod/winch system that requires no power. Careful selection of an appropriate multiyear ice floe is needed to prolong the lifetime of the system (up to 3 years depending on the profiling schedule). Shortly after deployment, each ITP begins profiling the water column at its programmed sampling interval. After each acquired temperature and salinity profile, the underwater unit (PROCON) transfers the data and engineering files using an inductive modem to the surface controller (SURFCON). SURFCON also accumulates battery voltages, buoy temperature, and locations from GPS at specified intervals in status files, and queues that information for transmission at the start of each new day. At frequent intervals, an Iridium satellite transceiver in the surface package calls and transmits queued status and CTD data files onto a WHOI logger computer, which are subsequently processed and displayed in near-real time at http://www.whoi.edu/itp. In 2004 and 2005, three ITP prototypes were deployed in the Arctic Ocean. Each system was programmed with accelerated sampling schedules of multiple one-way traverses per day between 10 and 750-760 m depth in order to quickly evaluate endurance and component fatigue. Two of the ITPs are continuing to function after more than 10 months and 1200 profiles. Larger motor currents are observed at times of fast ice floe motion when larger wire angles develop and drag forces on the profiler are increased. The CTD profile data so far obtained document interesting spatial variations in the major water masses of the Beaufort Gyre, show the double-diffusive thermohaline staircase that lies above the warm, salty Atlantic layer, and many mesoscale eddys. Deployed together with CRREL Ice Mass Balance (IMB) buoys, these ITP systems also operate as part of an Ice Based Observatory (IBO). Data returned from an array of IBOs within an Arctic Observing Network will provide valuable real time observations, support studies of ocean processes, and facilitate numerical model initialization and validation.
Feasibility study of non-invasive telemetry techniques for use with submarine telephone cables

(Woods Hole Oceanographic Institution, 1993-01) Brown, Neil L. ; Frye, Daniel E. ; Proakis, John

The feasibility of using inductive coupling with existing submarine telephone cables for telemetry of data from ocean sensors was investigated. The submarine telephone cable was simulated with a computer model and the model results were tested experimentally by deploying 600 meters of coax cable in Woods Hole Harbor. In parallel a study of the optimum access methods and modulation and techniques was performed. Results of the feasibility study showed that a non-invasive technique for inductive coupling is not feasible for use with existing SF and SD coaxial cable designs. Signals induced in both conductors by a toroid encircling the cable remain identical as they propagate along the cable as a result of mutual inductance. Thus, no signals are apparent at the repeaters. Optimal use of cable bandwidth combines time division multiple access with trellis-coded QAM modulation.
Advanced Engineering Laboratory project summaries 1992

(Woods Hole Oceanographic Institution, 1994-05) Frye, Daniel E.

The Advanced Engineering Laboratory of the Woods Hole Oceanographic Institution is a development laboratory within the Applied Ocean Physics and Engineering Deparment. Its function is the development of oceanographic instrumentation to test developing theories in oceanography, and to enhance current research projects in other disciplines within the community. This report summarzes recent and ongoing projects perfomied by members of this laboratory.
Advanced Engineering Lab project summaries 1991

(Woods Hole Oceanographic Institution, 1993-01) Frye, Daniel E.

The Advanced Engineering Laboratory of the Woods Hole Oceanographic Institution is a development laboratory within the Applied Ocean Physics and Engineering Department. Its function is the development of oceanographic instrumentation to test developing theories in oceanography, and to enhance current research projects in other disciplines within the community. This report summarizes recent and ongoing projects performed by members of this laboratory.
ESOM I and II final report

(Woods Hole Oceanographic Institution, 1991-11) Bocconcelli, Alessandro ; Berteaux, Henri O. ; Frye, Daniel E. ; Prindle, Bryce

An Engineering Surface Oceanographic Mooring (ESOM) program was initiated in 1989 by the Woods Hole Oceanographic Institution for the purpose of evaluating the long term, in situ performance of new moored array materials and sensors. For logistic and practical reasons, a site 12 miles southwest of Bermuda, with a water depth of 3000m was selected to deploy the mooring. Following well established design practice the upper part of the mooring down to a depth of 1900m was made of plastic jacketed, steel armored wire ropes and cables. Groups of test samples were attached at different depths to the main mooring line. The lower part of the mooring was made of compliant, plaited nylon rope. The mooring was deployed in March 1989. It was recovered and reset, with a vertical acoustic telemetry prototype system, in April 1990. The at-sea phase of the program ended in November 1990 when the termination of a test cable failed and the mooring broke loose. The entire mooring was recovered and all of its samples and components were carefully inspected and tested. In addition to the novel acoustic link, mooring components tested included new wire ropes, new electromechanical cables and their terminations, low drag fairings, fishbite resistant jackets, and a new type of surface buoy.
Surface-wave data acquisition and dissemination by VHF packet radio and computer networking

(Woods Hole Oceanographic Institution, 1988-04) Briscoe, Melbourne G. ; Denton, Elsie ; Frye, Daniel E. ; Hunt, Mary M. ; Montgomery, Ellyn T. ; Payne, Richard E.

Waverider buoy data are normally transmitted on a 27 MHz analog radio link to a shore station a few miles away, where the buoy data are plotted on a paper strip-chart recorder or logged digitally for later computer processing. Instead, we have constructed a relay station on Martha's Vineyard island that retransmits the received Waverider data over a digital, 148 MHz packet-radio link to a personal computer in our laboratory on Cape Cod, where the data are edited, processed, spectrally analyzed, and then sent over an Ethernet line to our Institution mainframe computer for archiving. Telephone modem access of a special wave-data file on the mainframe permits unattended data dissemination to the public. The report describes the entire system, including Waverider buoy mooring hardware, computer programs, and equipment. The purpose of the project was to learn what difficulties are involved in the automated acquisition and dissemination of telemetered oceanographic data, and to gain experience with packet radio techniques. Although secondary to these purposes, the long-term surface-wave monitoring off the southwest shore of Martha's Vineyard has its own scientific, engineering, and environmental benefits.
Real-time tomography mooring

(Woods Hole Oceanographic Institution, 1992-06) Lynch, James F. ; Frye, Daniel E. ; Peal, Kenneth R. ; Liberatore, Stephen P. ; Kery, Sean M. ; Hobart, Edward ; Newhall, Arthur E. ; Smith, Stephen P.

A real-time tomography system has been developed which combines ocean acoustic tomography with satellite-based time keeping and satellite telemetry. The basis of the system is the acoustic tomography transceiver and its associated acoustic navigation grid. To this basic system, a link to the surface has been added to provide a pathway for telemetry of the tomographic data to shore and a downlink for satellite-derived time which is used to correct the transceiver's clock. The surface buoy contains a GPS receiver, clock comparator, system controller and multiple ID Argos transmitters. Processed tomography signals, transceiver location data time, time drift and surface buoy engineering data are transmitted to satellite using a total of 32 data buffers transmitted every eight minutes. The report describes the real-time tomography system in detail, with particular emphasis on the modifications implemented to convert the standard tomography instrument to a real-time oceanographic tool.
Advanced Engineering Laboratory project summaries : 1995-1996

(Woods Hole Oceanographic Institution, 1997-07) Frye, Daniel E.

The Advanced Engineering Laboratory of the Woods Hole Oceanographic Institution is a development laboratory within the Applied Ocean Physics and Engineering Department. Its function is the development of oceanographic instrumentation to test developing theories in oceanography and to enhance current research projects in other disciplines within the community. This report summarizes recent and ongoing projects performed by members of this laboratory.
Advanced Engineering Laboratory project summaries 1994

(Woods Hole Oceanographic Institution, 1996-04) Frye, Daniel E.

The Advanced Engineering Laboratory of the Woods Hole Oceanographic Institution is a development laboratory within the Applied Ocean Physics and Engineering Department. Its function is the development of oceanographic instrumentation to test developing theories in oceanography and to enhance current research projects in other disciplines within the community. This report summarizes recent and ongoing projects performed by members of this laboratory.
Atlantic Long-Term Oceanographic Mooring (ALTOMOOR)

(Woods Hole Oceanographic Institution, 1996-03) Frye, Daniel E. ; Merriam, Steve ; Eastwood, Robert L. ; Kemp, John N. ; McPhee, Neil M. ; Liberatore, Stephen P. ; Hobart, Edward ; Bocconcelli, Alessandro ; Tarbell, Susan A.

The Atlantic Long-Term Oceanogrphic Mooring (ALTOMOOR) has been maintained offshore Bermuda since 1993 as a testbed for the evaluation of new data telemetry technologies and new oceanographic instrumentation. It is currently a joint project between the Woods Hole Oceanographic Institution and the University of Southern California This report documents the WHOI contributions which have focused on the development of new data telemetry methods and new mooring technology. Details of the instrumentation evaluations will be published separately. A new inductively-coupled telemetry technology for ocean moorings has been developed and tested on ALTOMOOR. The inductive link uses standard, plastic-jacketed mooring wire as the transmission path for data generated at the individual instruments installed on the mooring. The signals are inductively linked to the mooring wire via toroids clamped around the wire, thus avoiding the need for multiconductor electromechanical cables terminated at each instrument. Seawater provides the electrical return path. The inductive modems send and receive data at 1200b/s. A controller in the surface buoy collects data from each of the subsurface instruments and forwards the data to shore by traditional satellite telemetry (Argos) and by short range radio using a nearby ship as a store and forward node. The buoy-to-ship link operates over about 2 km at 10kBytes/sec. When the ship docks, data are offloaded automatically to a computer on shore which can be accessed via the Internet.
Performance of a new generation of acoustic current meters

(American Meteorological Society, 2007-02) Hogg, Nelson G. ; Frye, Daniel E.

As part of a program aimed at developing a long-duration, subsurface mooring, known as Ultramoor, several modern acoustic current meters were tested. The instruments with which the authors have the most experience are the Aanderaa RCM11 and the Nortek Aquadopp, which measure currents using the Doppler shift of backscattered acoustic signals, and the Falmouth Scientific ACM, which measures changes in travel time of acoustic signals between pairs of transducers. Some results from the Doppler-based Sontek Argonaut and the travel-time-based Nobska MAVS are also reported. This paper concentrates on the fidelity of the speed measurement but also presents some results related to the accuracy of the direction measurement. Two procedures were used to compare the instruments. In one, different instruments were placed close to one another on three different deep-ocean moorings. These tests showed that the RCM11 measures consistently lower speeds than either a vector averaging current meter or a vector measuring current meter, both more traditional instruments with mechanical velocity sensors. The Aquadopp in use at the time, but since updated to address accuracy problems in low scattering environments, was biased high. A second means of testing involved comparing the appropriate velocity component of each instrument with the rate of change of pressure when they were lowered from a ship. Results from this procedure revealed no depth dependence or measurable bias in the RCM11 data, but did show biases in both the Aquadopp and Argonaut Doppler-based instruments that resulted from low signal-to-noise ratios in the clear, low scattering conditions beneath the thermocline. Improvements in the design of the latest Aquadopp have reduced this bias to a level that is not significant.
Expendable oceanographic mooring (XMOOR)

(Woods Hole Oceanographic Institution, 1997-04) Frye, Daniel E. ; Peters, Donald B. ; Arthur, Richard

An expendable, self-deploying mooring (XMOOR) for shallow water applications has been developed to address Navy requirements for environmental monitoring. The project has been conducted jointly between the Woods Hole Oceanographic Institution and the Naval Research Laboratory at Stennis, MS. WHOI has taken the lead on the mechanical design of the system while NR has developed the electronics. Eight prototype XMOOR systems have been built. They are designed for water depths between 10 and 100m, for deployments of up to 3-months duration, and for automatic deployment. Their sensor suite includes barometrc pressure, air temperatue, water temperature at up to 25 levels, and conductivity and pressure at up to 3 levels. Data telemetry is accomplished via the Argos DCS and by line-of-sight VH confguration of the data collection program. This report describes the XMOOR mechanical system. The data collection and telemetry systems are described separately in (1) and (2).
Design and evaluation of a directional antenna for ocean buoys

(Woods Hole Oceanographic Institution, 1997-11) Frye, Daniel E. ; Doherty, Kenneth W. ; Hinton, Al

A system concept has been developed by Viasat, Inc. and Woods Hole Oceanographic Institution for improving the data telemetry bandwidth available on ocean buoys. This concept utilizes existing communications satellites as data relay stations and mechanically steered antenna arrays to achieve increased data rates and improved power efficiency needed for ocean applications. This report describes an initial feasibility and design study to determine if a mechanically steered antenna array can meet the requirements of open ocean buoy applications. To meet the system requirements, an 18-element microstrip antenna (9-element transmit, 9-element receive) was designed and fabricated under subcontract by Seavey Engineering Associates, Inc. It operates in the 4-6GHz frequency band (C-band) and provides 14 dB of gain. The 1/2 power beamwidth is +-t5° in azimuth and elevation. This antenna design, in conjunction with a simple rotating mount, was used to evaluate the potential of this approach to keep a geostationary satellite in view when mounted on an ocean buoy. The evaluation is based on laboratory measurements using a magnetic compass and a small stepper motor to maintain antenna orientation while the complete assembly was rotated and tilted at speeds similar to what would be expected on an offshore buoy equipped with a stabilizing wind vane. The results are promising, but less than conclusive because of limitations in the experimental test setup. The recent introduction of several commercially available mechanically steered antennas designed for use on small boats may provide a viable alternative to the approach described here with appropriate modification to operate at C-band.
Advanced Engineering Lab project summaries 1990

(Woods Hole Oceanographic Institution, 1991-05) Frye, Daniel E.

The Advanced Engineerig Laboratory of the Woods Hole Oceanographic Institution is a development laboratory within the Applied Ocean Physics and Engineering Department. Its function is the development of oceanographic instrumentation to test developing theories in oceanography, and to enhance current reseach projects in other disciplines within the community. This report summarizes recent and ongoing projects performed by members of this laboratory.
Advanced Engineering Laboratory project summaries 1993

(Woods Hole Oceanographic Institution, 1994-12) Frye, Daniel E.

The Advanced Engineering Laboratory of the Woods Hole Oceanographic Institution is a development laboratory within the Applied Ocean Physics and Engineering Deparment. Its function is the development of oceanographic instrumentation to enhance current research projects in other disciplines within the community. This report summarizes recent and ongoing projects performed by members of this laboratory.
Advanced Engineering Laboratory project summaries 1989

(Woods Hole Oceanographic Institution, 1990-05) Frye, Daniel E. ; Stone, Ellen ; Martin, Ann

The Advanced Engineering Laboratory of the Woods Hole Oceanographic Institution is a development laboratory within the Applied Ocean Physics and Engineering Department. Its function is the development of oceanographic instrumentation to test developing theories in ocean physics, and to enhance current research projects in other disciplines within the oceanographic community. This report summarizes recent and ongoing projects performed by members of the laboratory.
Data telemetry, assimilation and ocean modeling : semi-annual report for the period October 1, 1986 to April 1, 1987

(Woods Hole Oceanographic Institution, 1987-06) Frye, Daniel E. ; Woods Hole Oceanographic Institution ; Massachusetts Institute of Technology ; Harvard University

The University Research Initiative Program is a cooperative project between woods Hole oceanographic Institution, Massachusetts Institute of Technology and Harvard. The objectives of this 5-year Office of Naval Research funded program are to advance the state of the art in ocean data telemetry, interpretation of remotely sensed data from satellite, and numerical modeling of ocean circulation. Ocean data telemetry is being addressed by several development projects whose aim is to reliably transfer data from in situ oceanographic instruments to laboratory computers on the shore. The satellite oceanography group is developing expertise in analyzing, manipulating, displaying and archiving data from all of the major satellite oceanographic sensors. The numerical modeling initiative is working on a family of circulation models which can be connected at their boundaries to cover the important mesoscale and basin wide flow regimes. These ambitious plans are intended to bring new technologies developed in the communications, electronics, satellite sensing and computer science fields into everyday use in oceanography so that they can be ready for the global science programs planned for the 1990's.

Frye Daniel E.

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