High-frequency Radar Measurements of Coastal Ocean Surface Currents
Author: Daniel Martin Fernandez
Publisher:
Published: 1993
Total Pages: 382
ISBN-13:
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HF Radar Measurements of Ocean Surface Currents and Winds
Author:
Publisher:
Published: 2002
Total Pages: 6
ISBN-13:
DOWNLOAD EBOOKThe 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.
VHF Radar Measurements of Ocean Surface Currents from a Moving Ship
Author:
Publisher:
Published: 1995
Total Pages: 61
ISBN-13:
DOWNLOAD EBOOKShore-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).
Coastal Ocean Dynamics Applications Radar
Author: Thomas Martin Georges
Publisher:
Published: 1985
Total Pages: 360
ISBN-13:
DOWNLOAD EBOOKMeasuring Ocean Currents
Author: Antony Joseph
Publisher: Newnes
Published: 2013-08-12
Total Pages: 447
ISBN-13: 0123914280
DOWNLOAD EBOOKMeasuring 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
Validation of High Frequency Radar Used in Ocean Surface Current Mapping Via In-situ Drifting Buoys
Author:
Publisher:
Published: 2008
Total Pages: 110
ISBN-13:
DOWNLOAD EBOOKHigh frequency (HF) radar and its application to mapping ocean surface currents is a relatively new field of study in oceanography. Nevertheless, this scientific field produces real, tangible, accurate real-time results readily available to the military operational planner. The information gained through this process aids in the planning and execution of littoral operations via the development of the battle-space environment. Additionally, commercial use of this information can aide in the containment of coastal oil spills, efforts in search and rescue, and the execution of coastal engineering projects. Indeed, the utilization of High Frequency radar in the ocean environment has many beneficial qualities used by a wide variety of organizations. This study focuses on the validation aspects of High Frequency radar through the use of four drifters placed in-situ from 23-27 January 2008 on the Central California Coast from Monterey to San Francisco. A second experiment was conducted from 01-10 April 2008 involving 32 drifters placed west of the San Francisco Bay. Various statistical comparisons of radial current velocity data from 12 CODAR (Coastal Ocean Dynamics Application Radar) stations to the radial velocity data of each of the drifters will be analyzed.
Calibration and Validation of High Frequency Radar for Ocean Surface Current Mapping
Author: Kyung C. Kim
Publisher:
Published: 2004-06-01
Total Pages: 92
ISBN-13: 9781423518273
DOWNLOAD EBOOKHigh 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.
Oceanography - High Frequency Radar and Ocean Thin Layers, Volume 10
Author:
Publisher:
Published: 1999
Total Pages: 77
ISBN-13:
DOWNLOAD EBOOKPartial 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.
Measurements of Near Surface Ocean Currents Using HF Radar
Author: Kenneth Laws
Publisher:
Published: 2001
Total Pages: 378
ISBN-13:
DOWNLOAD EBOOKAn Investigation of Surface Current Patterns Related to Upwelling in Monterey Bay, Using High Frequency Radar
Author: Andres Enriquez
Publisher:
Published: 2004-06-01
Total Pages: 101
ISBN-13: 9781423518105
DOWNLOAD EBOOKHigh Frequency (HF) radar backscatter instruments are under development and testing in the marine science and defense science communities for their abilities to remotely sense surface parameters in the coastal ocean over large areas. In the Navy context, the systems provide real-time mapping of ocean surface currents and waves critical to characterization and forecasting of the battlespace environment. In this study, HF radar, aircraft and satellite information were used to investigate and describe surface current in Monterey Bay, California, for a period of ten months, from June 1, 2003 to March 31, 2004. A network of five CODAR-type HF radar instruments measured hourly surface currents over the bay. The measurements were averaged over one-hour intervals and total surface velocities were mapped on a grid in the Monterey Bay. Major upwelling events were observed during the period of June 14 to June 27, July 4 to July 19, August 8 to August 18 and other upwelling events were observed until late October. These periods of upwelling favorable winds are common during summer with durations of 10 to 20 days. Cyclonic circulation cells are developed on shore during upwelling conditions and an anticyclonic circulation in the middle of the bay is observed when the wind shifts to the southwest producing a strong flow out of the bay close to the coastline off Point Pi os. Downwelling conditions are much less common than upwelling, with occurrences during winter and early fall storms with events lasting between two to five days. When the wind blows to the northeast with an intensity of 4 m/s or more for more than 12 hours, a well developed anticyclonic gyre forms in the middle of the bay. This is associated with a strong current, 35 to 40 cm/s, which flushes out in the southern part of the bay close to the coast off Point Pi os. This flow reverses when the winds veer to the southwest and enter into the Bay with less intensity.
