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<DIV><FONT size=4>Radar technology 'could dramatically increase tsunami warning
times'</FONT></DIV>
<DIV class=author>T. V. Padma</DIV>
<DIV class=source>12 June 2012</DIV>
<DIV class=date><A
href="http://www.scidev.net/en/agriculture-and-environment/tsunami/news/radar-technology-could-dramatically-increase-tsunami-warning-times-.html">http://www.scidev.net/en/agriculture-and-environment/tsunami/news/radar-technology-could-dramatically-increase-tsunami-warning-times-.html</A></DIV>
<DIV class="article_content cf">
<P><SPAN>[NEW DELHI] A <A
href="http://www.scidev.net/en/new-technologies/"><FONT color=#336699>new
formula</FONT></A> that uses high frequency radar data to detect incoming <A
href="http://www.scidev.net/en/agriculture-and-environment/tsunami/"><FONT
color=#336699>tsunamis</FONT></A> could provide tsunami warnings up to an hour
before their arrival at a coastline. </SPAN></P>
<P><SPAN>In September last year, researchers studying the tsunami generated by
the <A
href="http://www.scidev.net/en/agriculture-and-environment/natural-disasters/"><FONT
color=#336699>earthquake</FONT></A> in Japan in March 2011, <A
href="http://www.scidev.net/en/agriculture-and-environment/tsunami/news/radar-could-detect-tsunamis-more-accurately.html"><FONT
color=#336699>raised hopes of the potential for radar data to detect
tsunamis</FONT></A>. </SPAN></P>
<P><SPAN>Now, researchers at CODAR Ocean Sensors, United States, have developed
an algorithm that would automatically detect a tsunami within eight minutes of
the wave's arrival in the radar sensor's coverage area. </SPAN></P>
<P><SPAN>The algorithm was tested using data — also generated during the March
2011 earthquake — from 14 high frequency radar sites in Japan and the United
States. The findings have now been reported in the journal, <EM>Remote
Sensing.</EM> </SPAN></P>
<P><SPAN>Use of the algorithm would enable significant advance warning of
tsunamis in locations where shallow waters (less than 200 metres deep) extend
well off-shore — for example, across much of South East Asia, the west coast of
India and the US east coast — according to Belinda Lipa, the study's lead
author<EM>.</EM> </SPAN></P>
<P><SPAN>"Typically, 15 to 30 minutes' advance [warning] can be provided in
regions with little continental shelf, where the water gets deep rapidly," Lipa
told <EM>SciDev.Net. </EM>"In regions with a shallow shelf, which extends
further offshore, over an hour is possible." </SPAN></P>
<P><SPAN>In the open ocean, a tsunami has a low height, an extremely long
wavelength and travels at high speeds, and hence can be detected in real time
only by pressure sensors at the bottom of the ocean, Lipa explained. </SPAN></P>
<P><SPAN>But as it moves towards shallower waters, the wave slows down, and its
height and orbital velocity increase, making it detectable by radar. </SPAN></P>
<P><SPAN>"High frequency (HF) radar installations at such locations could
provide vital capability for the detection and measurement of the local
intensity of deadly approaching tsunamis," Lipa said. </SPAN></P>
<P><SPAN>She added that HF radar systems are already in place at many coastal
locations around the world to monitor surface currents and waves. </SPAN></P>
<P><SPAN>"Tsunami-watch software could run in the background, activating a
warning should a tsunami be detected, before local infrastructure is damaged,"
she said. </SPAN></P>
<P><SPAN>Basant Kumar Jena, a researcher at India's National Institute of Ocean
Technology in Chennai, told <EM>SciDev.Net</EM> that prior to the 2011 Japan
quake, scientists didn't have the data needed to validate the potential
inclusion of radar technology in tsunami warning systems. </SPAN></P>
<P>"<SPAN>The data collected from the various radars along the US and Japanese
coasts confirms the capability of HF radars technique to detect tsunamis," he
said, adding that the discovery would also enable scientists "to improve the
software which detects the tsunami signature from radar data". </SPAN></P>
<P><SPAN>Satheesh Shenoi, director of the Hyderabad-based Indian National Ocean
Information System, which houses India's tsunami warning system, told
<EM>SciDev.Net</EM> that radar technology would be a valuable addition to
multi-faceted tsunami warning systems. </SPAN></P>
<P><A href="http://www.mdpi.com/2072-4292/4/5/1448" target=_blank><FONT
color=#336699>Link to full article</FONT></A></P></DIV></FONT><BR>
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