Download or read book Measurements of Near Surface Ocean Currents Using HF Radar written by Kenneth Laws and published by . This book was released on 2001 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Real time Measurement of Wide area Near surface Ocean Current written by Samareh Attarsharghi and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Of all of the physical parameters of the ocean realm, the speed and direction of the movement of ocean water, otherwise referred to as ocean "current," is one of the most problematic to characterize. Currents influence the global climate, used for producing power, are crucial in determining the oil spill trajectories and ocean contaminant control, can either work against or with the movement of ships at sea and govern the movements of icebergs. Icebergs are a threat to offshore industries and marine transportations, particularly in places like the Northwest Atlantic, because of damages they can cause once they strike the oil platforms or ship hulls. They are steered by the near-surface current and not the surface current. Therefore, measurment of the real-time ocean currents at desired depths is valuable for the industries or researchers who are dealing with or studying the oceanographic data. Ocean current measurment methods that are currently being employed for ocean monitorings, are not able to measure the real-time current at certain desired depths over a larg area of the ocean. Thus, the existing current measurement methods need improvements. Limitations of the existing methods are as follows. Acoustic dopler current profilers (ADCP), are one of the most popular methods employed by most of the industries dealing with the oceanograghy. ADCPs are capable of measuring the current at any desired depth; however, their measurement method is of a point nature and they cannot measure an area averaged current data. Other techniques such as high frequency radio detecting and ranging systems (HF-RADAR) are also used to measure the surface currents (down to 15 m). These shore-based current meters with radio antenna, follow the same premise of the ADCP. In other words their measurement is dependant on the Doppler effect to determine the direction and velocity of the currents; however, they are capable of evaluating only the surface currents and not the near-surface currents (70-100 meter of depth is considered in this thesis as this is the depth oil structures are deployed in the Northwest Atlantic Ocean). Another group of instruments used for current measurement are floats and drifters which report their data to a centre device which is usually a satelite. The current data obtained with these instruments are fed into modeling systems, e.g. in (Chassignet, Hurlburt et al. 2006), for the ocean forcasting. The problems that exist with the available real-time current data from the satelite is that it is the very shallow current data (down to 15m that can be called surface). The data from other devices like floats is very sparse to include the horizontal information. Hence, Chassignet et al. use data assimilation of the past knowledge and ocean dynamics in order to predict the ocean features. Therefore, it is important to develop a method by which adequate data could be provided for the ocean prediction and modeling system. Thus, the focus of this thesis is on designing a method which is real-time and measures the near-surface current. On the other hand, energy suplies to the instruments in open water is limited as they work mainly rely on batteries and it is difficult to access the instruments in harsh condition to replace the batteries. Moreover, in cold regions the solar power is very limitted and thus using solar cells is not practical. Therefore, in order to measure the ocean current in real time, a novel method along with a sustainable architechture design is being proposed in this dissertation. The new method is based on transit time with the difference that in transit time method waves need to travel in both directions; up- and down-stream. But with a modification in the newly designed architecture; which is adding an extra node in the center of the network's cells, sound waves need to travel on only one direction. This helps with saving a great amount of energy and covering a larger area in comparison with the networks which are developed using transit time method. Experimental results as well as simulations verify that the new proposed method is both efficient and practical.
Download or read book Measuring Ocean Currents written by Antony Joseph and published by Newnes. This book was released on 2013-08-12 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measuring Ocean Currents: Tools, Technologies, and Data covers all major aspects of ocean current measurements in view of the implications of ocean currents on changing climate, increasing pollution levels, and offshore engineering activities. Although more than 70% of the Earth is covered by ocean, there is limited information on the countless fine- to large-scale water motions taking place within them. This book fills that information gap as the first work that summarizes the state-of-the-art methods and instruments used for surface, subsurface, and abyssal ocean current measurements. Readers of this book will find a wealth of information on Lagrangian measurements, horizontal mapping, imaging, Eulerian measurements, and vertical profiling techniques. In addition, the book describes modern technologies for remote measurement of ocean currents and their signatures, including HF Doppler radar systems, satellite-borne sensors, ocean acoustic tomography, and more. Crucial aspects of ocean currents are described in detail as well, including dispersion of effluents discharged into the sea and transport of beneficial materials—as well as environmentally hazardous materials—from one region to another. The book highlights several important practical applications, showing how measurements relate to climate change and pollution levels, how they affect coastal and offshore engineering activities, and how they can aid in tsunami detection. Coverage of measurement, mapping and profiling techniques Descriptions of technologies for remote measurement of ocean currents and their signatures Reviews crucial aspects of ocean currents, including special emphasis on the planet-spanning thermohaline circulation, known as the ocean's "conveyor belt," and its crucial role in climate change
Download or read book Comparisons of Near Surface Currents Measured by Hf Radar and Current Meters written by C. R. Griffiths and published by . This book was released on 1991 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Ocean Surface Measurements with HF Radar written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: HF surface wave radar for ocean wave and current measurements began with collaborative work at Stanford University and Scripps Institution of Oceanography in the late 1960's. Two of the participants in this project (Drs. Teague and Vesecky) have worked with HF radar observations of the ocean since these early experiments. Under this grant a new HF radar design was begun and some prototype construction completed. This work led to construction of a full scale prototype that is now being tested over Monterey Bay, California from a field site kindly provided at the Long Marine Laboratory of the University of California at Santa Cruz. Initial results, including radial current field maps at four frequencies and variations of currents with time, were presented at the American Geophysical Union Fall Meeting in San Francisco, December, 1996. This final report is a presentation of results under the funding from ONR grant N00014-94-1-0371. It contains an overview of the radar design and its implementation in hardware as well as some preliminary results on vertical shear in the surface current field over Monterey Bay CA.
Download or read book HF Radar Measurements of Circulation in the Eastern Strait of Juan de Fuca Near Protection Island July 1979 written by Shelby Frisch and published by . This book was released on 1980 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book HF Radar Measurements of Ocean Surface Currents and Winds written by and published by . This book was released on 2002 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project began with the construction and deployment of two and later three multifrequency HF radar instruments (called MCR for Multifrequency Coastal Radar) to Monterey Bay, California. Further experiment deployments were to the Virginia coast and to Lake Michigan for fresh water experiments (NSF sponsorship). The data collected at these sites is reduced, analyzed and interpreted to achieve the specific research objectives listed below: 1. Improvement of radar performance by upgrading hardware and software and developing improved transmit antennas, signal processing and flexible use of multiple frequencies 2. Improvement of HF radar estimates of surface currents, vertical shear, winds, friction velocity and waves by improved estimation algorithms that use knowledge of air-sea interaction physics 3. Estimate surface wind speed and direction using multifrequency HF radar measurements by exploiting air-sea interaction physics and HF radar measurements of vertical current shear 4. Ocean science investigations, including assimilation of HF radar data into coastal ocean models for circulation, chemical and biological properties as well as air-sea interaction studies 5. Use of continuing HF radar observations on Monterey Bay in observing ships to assess the usefulness of multiple frequency HF radar in ship detection and tracking.
Download or read book Comparison of Near surface Currents Measured by Acoustic and Electromagnetic Current Meters with HF Radar Current Measurements written by C. R. Griffiths and published by . This book was released on 1985 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coastal Ocean Dynamics Applications Radar written by Thomas Martin Georges and published by . This book was released on 1985 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Ocean Waves and Surface Currents with HF Radar written by E. Gill and published by . This book was released on 1992 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Errors in HF Radar Ocean Current Measurements written by Tatsuya Najima and published by . This book was released on 2005 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book VHF Radar Measurements of Ocean Surface Currents from a Moving Ship written by and published by . This book was released on 1995 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shore-based, high frequency (HF) and very high frequency (VHF) radar systems for measuring ocean surface currents have been well detailed in the literature. The use of these systems has been limited to coastal ocean applications since both of the required radar sites must be positioned ashore. To relieve the geometric constraints imposed by two shore sites and allow coverage of more coastal areas, necessitates at least one sea-based system (Skop et al., 1994). Reducing the number of required sites to one increases the ocean area that can be measured. The feasibility of using a single, VHF radar system based on a moving ship for both near shore and deep water area coverage is the subject of this report. In December 1993 and July 1994 a near shore, ship-based data set was taken off the east coast of Key Biscayne, Florida, with overlapping coverage by a shore-based site. The July 1994 experiment also saw deep water data sets acquired as the ship described a square pattern to obtain overlapping grid coverage from the ship itself. The measurement and reduction of ship-induced contamination in the returned Doppler spectra are detailed. By combining ship and shore radial data, two vector current maps off north and south Key Biscayne a obtained. Using the same methodology, the vectorization of the deep water radials produces two more vector current maps from on transmit-receive ship-based site. The deep water surface current maps are dominated by the high speed, northerly flowing Florida Current and are quite accurate. The Key Biscayne surface current maps are less accurate, being dominated by pseudo-currents that are introduced through GPS errors in ship position. These GPS errors lead to inaccurate calculations of the ship velocity and, hence, to inaccurate removal of the ship-induce Doppler currents from the measured currents. (MM).
Download or read book H F Radar Measurements of Surface Currents in the Eastern Irish Sea written by David Prandle and published by . This book was released on 1992 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Measurement of Near shore Surface Currents Along the South Coast by HF Radar written by R. D. Palmer and published by . This book was released on 1989 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Encyclopedia of Oceanography written by Rhodes Whitmore Fairbridge and published by . This book was released on 1969 with total page 1021 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oceanography High Frequency Radar and Ocean Thin Layers Volume 10 written by Larry Atkinson and published by . This book was released on 1999 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: Partial contents include: (1) HF Radar Instruments, Past to Present; (2) Mapping Surface Currents in Monterey Bay with CODAR-type HF Radar; (3) The Coastal Jet: Observations of Surface Currents over the Oregon Continental Shelf from HF Radar; (4) Tidal and Wind-driven Currents from OSCR; (5) Larval Transport and Coastal Upwelling: an Application of HF Radar in Ecological Research; (6) Evolution of Bearing Determination in HF Current Mapping Radars; (7) Shipboard Deployment of a VHF OSCR System for Measuring Offshore Currents; and (8) Experience with Shipborne Measurements of Surface Current Fields by Radar.
Download or read book Use of Surface Currents Measured by HF Radar in Planning Coastal Discharges written by D. Prandle and published by . This book was released on 1987 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
