TSUNAMI EARLY DETECTION:ENHANCED RESOLUTION OF HF OCEANOGRAPHIC RADAR
No. 32 (2010), Swash, Nearshore Currents, and Long Waves
No. 32 (2010)

TSUNAMI EARLY DETECTION:ENHANCED RESOLUTION OF HF OCEANOGRAPHIC RADAR

Swash, Nearshore Currents, and Long Waves
https://doi.org/10.9753/icce.v32.currents.4
Published 2011-01-23
Yasuhiro Murata
KOKUSAI KOGYO CO.,LTD.
Toshiro Nagakura
KOKUSAI KOGYO CO.,LTD.
Takahiro Kokai
Nagano Japan Radio Co.,Ltd
Proceedings of the 32nd International Conference
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Keywords

Tsunami
Surface flow
HF Radar
Sea echo
Doppler shift
FFT
STFT
Zero-padding
Peak detection

How to Cite

Murata, Y., Nagakura, T., & Kokai, T. (2011). TSUNAMI EARLY DETECTION:ENHANCED RESOLUTION OF HF OCEANOGRAPHIC RADAR. Coastal Engineering Proceedings, 1(32), currents.4. https://doi.org/10.9753/icce.v32.currents.4
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Abstract

HF Oceanographic radar is an equipment, for instantaneously sensing velocity distribution of sea surface current. It has a wide field of view, which extends approximately ±45° in direction and beyond 50km in distance. There are high expectations that the radar observation of Tsunami will become a new road path for preventing disasters. In this paper, we describe a method to enhance the resolutions of radar in both time and current. At first, resolutions required for tsunami observation are estimated by simulating a Tokachi-oki earthquake tsunami (2003). Here it is pointed out that traditional data processing indicates inadequate resolutions for tsunami early detection. Secondly, two techniques are proposed to achieve the necessary resolutions. Short-time Fourier transform (STFT), in place of normal FFT, enhances the time resolution of Doppler analysis. Further, zero-padding technique improves the current resolution, by interpolation of data within the frequency domain. Finally, by means of simulation, it is verified that these proposed techniques give improved resolutions in both time and current.
https://doi.org/10.9753/icce.v32.currents.4
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References

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