Download or read book Measurement of Ocean Waves and Surface Currents with High Frequency Radar written by and published by . This book was released on 1992 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document illustrates the measurements of ocean waves and surface currents with a high frequency radar. It presents current maps of single- and dual-site radial and vector currents, windspeeds from the radar, and radar-deduced wave spectra. A summary is included.
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 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 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 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 Advanced Ocean Surface Measurements with HF Radar written by and published by . This book was released on 1997 with total page 26 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 Remote Sensing of Ocean Surface Current and Current Shear by HF Backscatter Radar written by Eng-Chong Ha and published by . This book was released on 1979 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Doppler spectrum of radar return from the sea at HF contains two narrow lines displaced upward and downward from the carrier frequency, resulting from backscatter off ocean surface waves moving toward and away from the radar, respectively. These Bragg lines indicate resonant backscatter which occurs for the ocean waves of length one-half the radio wavelength. The phase velocity of these gravity waves consists of two components; the first is determined by the wavelength and the second by the current component in the direction of wave propagation averaged over depth with an exponential weighting function that has a characteristic scale proportional to the wavelength. The Doppler shift of the radar carrier is determined by the wave phase velocity. Its variation with carrier frequency is thus related to the vertical profile of the current component in the radar direction by a Laplace transform; therein lies the principle of radio measurement of ocean current and its vertical shear. Radio backscatter experiments to verify the feasibility of such measurements were conducted using the radar operating at four frequencies covering the range from 3 to 30 MHz. The depth-averaged radial current deduced from the centroid of the Doppler-shifted sea echo experiments at 6.8, 13.3, 21.7, and 29.8 MHz showed fluctuations on the order of 1 cm/sec superimposed on temporal trends that reached maximum values of about 40 cm/sec. It is concluded that multifrequency backscatter ground-wave radar at HF constitutes a powerful technique for mapping current and its vertical profile in the top few meters of the ocean.
Download or read book Calibration and Validation of High Frequency Radar for Ocean Surface Current Mapping written by Kyung C. Kim and published by . This book was released on 2004-06-01 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: High Frequency (HF) radar backscatter instruments are being developed and tested in the marine science and defense science communities for their abilities to sense surface parameters remotely in the coastal ocean over large areas. In the Navy context, the systems provide real-time mapping of ocean surface currents and waves critical for characterizing and forecasting the battle space environment.
Download or read book High frequency Radar Measurements of Coastal Ocean Surface Currents written by Daniel Martin Fernandez and published by . This book was released on 1993 with total page 382 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 Surface Current and Wave Validation of a Nested Regional HF Radar Network in the Mid Atlantic Bight written by and published by . This book was released on 2009 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The National High Frequency Surface Current Mapping Radar Network is being developed as a backbone system within the Integrated Ocean Observing System (IOOS). Of the core variables recognized in the IOOS Development Plan, two can be measured by High Frequency Radar (HFR): ocean surface currents and ocean surface waves. Rutgers University operates a nested multi-frequency network of HF Radar systems along the coast of New Jersey. The network provides near real-time current observations with varying coverage from the coast to the shelf break. This is a subset of the larger regional coverage of the 26 site Mid-Atlantic HF Radar Consortium. The primary goal of this consortium is to operate the regional system in a coordinated way to guarantee the delivery of quality ocean current and wave data. In this paper we present the validation of both wave and current observations measured with this nested network. Particular emphasis is placed on surface current comparisons with Coast Guard deployed surface drifters (SLDMBs) and nearshore wave comparisons with moorings. The Coast Guard comparisons have a specific focus on quantifying the uncertainty in the HF radar surface current estimates as applied to search and rescue operations. These metrics will be used to ensure that quality data is going to the Coast Guard and that this information is properly incorporated into existing search planning tools. The nearshore measurements focus on algorithm development projects to incorporate shallow water effects into the estimates of nearshore waves.
Download or read book The High Frequency Surface Wave Radar Cross Section for Ocean Swell written by Chengxi Shen and published by . This book was released on 2013 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ocean Surface Current Estimation Using a Long range Single station High frequency Ground Wave Radar written by and published by . This book was released on 1999 with total page 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 Estimation of Vector Surface Currents Beyond the Region of Overlap of Dual site HF Radar written by Pradeep Bobby and published by . This book was released on 2003 with total page 290 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 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 The Theory of Hydrodynamic Stability written by C C (Chia-Chʻiao) 1916- Lin and published by Hassell Street Press. This book was released on 2021-09-09 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. To ensure a quality reading experience, this work has been proofread and republished using a format that seamlessly blends the original graphical elements with text in an easy-to-read typeface. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
