Showing papers by "National Ocean Service published in 1987"

Transmission of Real Time Oceanographic and Meteorologic Data From Ships

Abstract: The Shipboard Environmental [Data] Acquisition System (SEAS) was developed by the National Oceanic and Atmospheric Administration (NOAA) to provide accurate meteorological and oceanographic data from vessels in real-time through the use of satellite data transmission techniques. SEAS automatically transmits data through the GOES satellite system. Currently, SEAS has the capability to transmit ship surface weather observations, XBT data, CTD, and current profile data. The system is expandable and future upgrades to the system will include XCTD, automated meteorological sensors, and interfacing to an acoustic doppler current meter. SEAS is designed around an IBM PC compatible computer and requires 512K of memory and a 8087 coprocessor chip.

Development of a Real Time Measurement System for Charleston Harbour

Abstract: The National Ocean Service of NOAA has developed and deployed a real-time current measuring system for verification of the accuracy of the NOAA tidal current table for Charleston Harbor. An RD Instruments acoustic Doppler current profiler on the bottom of Charleston Harbor is hard wired to a Coastal Climate weather station. The weather station transmits both the weather data and the current profiler data to a shore station for telephone interrogation from Rookville, Maryland. Although there have been several engineering evaluations of acoustic Doppler current measuring systems, this is the first application of the technology to NOS operational programs. The paper will discuss the development, integration and performance of the system as well as techniques used to assure the quality of data.

Acoustic Remote Sensing of Wind Wave Directional Parameters

Abstract: A Marsh McBirney MODEL MMI-555 was moored for a period of 21 days in the vicinity of Ambrose Tower, N.Y. close to a special prototype bottom mounted 300kHz Ametek Straza acoustic Doppler current profiler. The MMI-555 was operated in the burst mode taking 60 samples at 1-second intervals, each hour. Variances of the horizontal water velocities, measured by the MMI-555 and rotated into the directions of the Ametek beams, are compared to standard deviations of water velocities measured on the Ametek beams in bins near the MMI-555 depth. paper provides further evidence in support of the authors previously stated hypothesis that directional waveheight spectra can be estimated from acoustic Doppler measurements.

Optimum Utilization of Positioning Data in SDS III

Abstract: A new, computerized hydrographic data acquisition and processing system, Shipboard Data System III (SDS III), is being designed and built for use by the National Ocean Service. An integrated positioning and navigation system is a critical element of this development. Design features include the ability to benefit from time-deskewed multiple lines of position from mixed sensor types (both electronic and manual), raw data quality evaluation including blunder removal and the use of signal strength data, high precision geodetic calculations, corrections for control and sensor offsets as well as for rare but difficult geometries, and the use of auxiliary speed and heading data in the application of advanced filtering and smoothing techniques for reduction of random noise and recognition of bias errors. Performance has been assessed for a variety of maneuvers via a track simulator which adds both vessel motions and sensor measurement noise. Results are extremely stable and robust. Measurement noise can be reduced by as much as a factor of three without adding significant biases, even on turns, while retaining actual random vessel motions. Operations can continue during complete losses of positioning data for limited but significant periods of time, including during maneuvers.

The Circulation and Water Level Forecast Atlas: A New Product in Development at NOS

Abstract: The National Ocean Service (NOS) is developing a new product aimed at improving the prediction of water level and currents in key waterways of the united States. The Circulation and Water Level Forecast Atlas will provide a series of charts and graphs for predicting the tide and tidal current anywhere in a particular estuary, and for providing information on the effects of wind, barometric pressure, and river discharge. The atlas will be produced using a numerical hydrodynamic model implemented for a particular estuary using an extensive oceanographic and meteorological data set. The atlas will represent the circulation at many more locations than the traditional NOS "Tidal Current Charts," which represent currents only at those locations where current data have been obtained and analyzed. The additional locations will include those of special navigational or environmental interest where current measurements cannot be made using traditional moored current meters. The additional spatial coverage resulting from the use of a numerical model will be especially evident in the atlas' tidal height charts, which will depict the changing water level over the entire waterway for each hour of the tidal cycle. On each chart coheight lines will traverse the entire waterway; tide predictions will no longer be limited to a few coastal locations. Use of a numerical hydrodynamical model, combined with the results of statistical data analyses, will also allow the synthesis of important meteorological and river effects in a way that will permit factors be applied to the tide or tidal current prediction based on wind, pressure, or river discharge information available to a user. In a waterway where NOS real-time water level gages are in operation, the atlas will supplement the NOS data retrieval software package called TIDES ABC, by providing a means to extrapolate the real-time data from these gages to other locations in the waterway. The first Circulation and Water Level Forecast Atlas is planned for Delaware River and Bay, where NOS conducted a 2 1/2-year circulation survey. The observations from that survey will be used to implement and assess the skill of the high-resolution numerical model that will be used to produce the atlas.

Innovative Tools for Management: Real-Time Oceanographic Measurements and Circulation Modeling

Abstract: Special applications of real-time water level and current data and results of circulation models promise substantial benefits, including economic gains and safety of life, property, and the environment. Potential economic benefits for maritime commerce alone are estimated conservatively at about $35.4 million annually for 22 United States ports, after deducting system operating costs. corresponding benefits include reduced deadtime waiting to enter or leave port, more efficient use of lightering and of tugs used for docking and undocking, and full use of the ship channel depths.