Ocean surface current prediction based on HF radar observations using trajectory-oriented association rule mining

Author(s):  
Kulsawasd Jitkajornwanich ◽  
Peerapon Vateekul ◽  
Upa Gupta ◽  
Teeranai Kormongkolkul ◽  
Arnon Jirakittayakorn ◽  
...  
2014 ◽  
Vol 31 (7) ◽  
pp. 1564-1582 ◽  
Author(s):  
Brian M. Emery ◽  
Libe Washburn ◽  
Chad Whelan ◽  
Don Barrick ◽  
Jack Harlan

Abstract HF radars measure ocean surface currents near coastlines with a spatial and temporal resolution that remains unmatched by other approaches. Most HF radars employ direction-finding techniques, which obtain the most accurate ocean surface current data when using measured, rather than idealized, antenna patterns. Simplifying and automating the antenna pattern measurement (APM) process would improve the utility of HF radar data, since idealized patterns are widely used. A method is presented for obtaining antenna pattern measurements for direction-finding HF radars from ships of opportunity. Positions obtained from the Automatic Identification System (AIS) are used to identify signals backscattered from ships in ocean current radar data. These signals and ship position data are then combined to determine the HF radar APM. Data screening methods are developed and shown to produce APMs with low error when compared with APMs obtained with shipboard transponder-based approaches. The analysis indicates that APMs can be reproduced when the signal-to-noise ratio (SNR) of the backscattered signal is greater than 11 dB. Large angular sectors of the APM can be obtained on time scales of days, with as few as 50 ships.


Author(s):  
Anna Dzvonkovskaya ◽  
Klaus-Werner Gurgel ◽  
Thomas Pohlmann ◽  
Thomas Schlick ◽  
Jiangling Xu

2016 ◽  
Vol 41 (4) ◽  
pp. 970-981 ◽  
Author(s):  
Guanghong Chang ◽  
Ming Li ◽  
Junhao Xie ◽  
Ling Zhang ◽  
Changjun Yu ◽  
...  

Author(s):  
Nguyen Thi Thu Mai ◽  
Alexei Sentchev ◽  
Tran Manh Cuong

Abstract: There are now over 350 high frequency radar (HF radar) stations operating on the coast of 37 countries around the world that allow the mapping of ocean surface current. However, observation from HF radars are often interrupted (loss of data) in both space and time due to signal inference, backscatters, ocean state.Therefore, in this study, we will present a method to improve the surface current data collected from HF radar system. Firstly, the radial surface current data will be filtered intermittently, then the result is interpolated over time and space by the orthogonal experimental EOF and the 2dVar bi-directional variable interpolation. In addition, the authors have initially applied 2dVar interpolation method to the HF radar data in Vietnam and received initial positive results. The methods used in this paper promise to be effective when applied to improve surface flow data obtained from HF radar stations in Vietnam in the future.   Keywords:EOF interpolation, 2dVar, Iroise sea, HF radar, ocean surface current.


2004 ◽  
Vol 38 (2) ◽  
pp. 102-108 ◽  
Author(s):  
Jeffrey D. Paduan ◽  
P. Michael Kosro ◽  
Scott M. Glenn

A description is given for a nation-wide surface current mapping system for the U.S. continental shelf regions based on the emerging capabilities of high frequency (HF) radar backscatter instruments. These HF radar systems have the advantages of being real-time, non-invasive, shore-based instruments capable of mapping ocean surface currents out to ranges of ∼200 km from shore. A framework for a national backbone system is described based on long-range HF radar systems and example results are provided from existing arrays off the northwest and northeast U.S. coastlines.


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