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Jeff
May17-04, 08:07 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Here\'s the problem:\n\nNearshore processes research (e.g., sediment transport, coastal erosion)\nis in desperate need of a new method for measuring the bathymetry of\nthe surf zone during storms. Vessel-borne methods, which generally\nuse some type of sonar, cannot be applied when the waves get big and\ncannot cover enough sea bottom fast enough. Airborne methods using\nlaser reflections (known as lidar) do not work in rainy weather, and\ncannot penetrate turbid water or through the bubbles associated with\nwaves.\n\nSo the question is, can anyone think of a physical principle that could\nbe applied scan the sea-surface, penetrate to the seabed, and give a\nreflective return that could be used to accurately measure the elevation\nof the seabed? Some of the requirements are:\n1. Impervious to turbidity and bubbles, seeing only the location\nof the density interface between water and the sandy sea bed.\n2. Mounted on an airplane or helicopter, such that a pattern of\nscanning from a relatively high altitude (e.g. 300 m) could cover a\nwide swath of sea surface.\n3. Must not injure people below.\n\nThanks.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>Here's the problem:

Nearshore processes research (e.g., sediment transport, coastal erosion)
is in desperate need of a new method for measuring the bathymetry of
the surf zone during storms. Vessel-borne methods, which generally
use some type of sonar, cannot be applied when the waves get big and
cannot cover enough sea bottom fast enough. Airborne methods using
laser reflections (known as lidar) do not work in rainy weather, and
cannot penetrate turbid water or through the bubbles associated with
waves.

So the question is, can anyone think of a physical principle that could
be applied scan the sea-surface, penetrate to the seabed, and give a
reflective return that could be used to accurately measure the elevation
of the seabed? Some of the requirements are:
1. Impervious to turbidity and bubbles, seeing only the location
of the density interface between water and the sandy sea bed.
2. Mounted on an airplane or helicopter, such that a pattern of
scanning from a relatively high altitude (e.g. 300 m) could cover a
wide swath of sea surface.
3. Must not injure people below.

Thanks.

Italo Vecchi
May24-04, 04:31 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\njlist1@yahoo.com (Jeff) wrote in message news:&lt;d83ad07c.0405161418.404c4846@posting.google. com&gt;...\n&gt; Here\'s the problem:\n&gt;\n&gt; Nearshore processes research (e.g., sediment transport, coastal erosion)\n&gt; is in desperate need of a new method for measuring the bathymetry of\n&gt; the surf zone during storms. Vessel-borne methods, which generally\n&gt; use some type of sonar, cannot be applied when the waves get big and\n&gt; cannot cover enough sea bottom fast enough. Airborne methods using\n&gt; laser reflections (known as lidar) do not work in rainy weather, and\n&gt; cannot penetrate turbid water or through the bubbles associated with\n&gt; waves.\n&gt;\n&gt; So the question is, can anyone think of a physical principle that could\n&gt; be applied scan the sea-surface, penetrate to the seabed, and give a\n&gt; reflective return that could be used to accurately measure the elevation\n&gt; of the seabed?\n\nI wonder how well defined the "elevation of the seabed" is in stormy\nweather. Reflection on a ill-defined boundary sounds tricky indeed. I\nsuggest that you provide some reference so that interested people and\npotential contributors may get some background on the topic.\nWould seeding the seabed with radio beacons and tracking their\nmovements during the storm provide useful information?\n\nIV\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>jlist1@yahoo.com (Jeff) wrote in message news:<d83ad07c.0405161418.404c4846@posting.google.com>...
> Here's the problem:
>
> Nearshore processes research (e.g., sediment transport, coastal erosion)
> is in desperate need of a new method for measuring the bathymetry of
> the surf zone during storms. Vessel-borne methods, which generally
> use some type of sonar, cannot be applied when the waves get big and
> cannot cover enough sea bottom fast enough. Airborne methods using
> laser reflections (known as lidar) do not work in rainy weather, and
> cannot penetrate turbid water or through the bubbles associated with
> waves.
>
> So the question is, can anyone think of a physical principle that could
> be applied scan the sea-surface, penetrate to the seabed, and give a
> reflective return that could be used to accurately measure the elevation
> of the seabed?

I wonder how well defined the "elevation of the seabed" is in stormy
weather. Reflection on a ill-defined boundary sounds tricky indeed. I
suggest that you provide some reference so that interested people and
potential contributors may get some background on the topic.
Would seeding the seabed with radio beacons and tracking their
movements during the storm provide useful information?

IV