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To: SunkenCiv; Boot Hill

Probably wouldn't expose underwater seamounts though!


3 posted on 03/28/2005 10:27:08 AM PST by Ernest_at_the_Beach (This tagline no longer operative....floated away in the flood of 2005 ,)
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To: Ernest_at_the_Beach
To the west of the ridge lies the Louisville seamount chain which is a chain of large undersea volcanoes having a length equal to the distance between New York and Los Angeles. These features are unfamiliar because they were discovered less than 20 years ago. The Louisville seamount chain was first detected in 1972 using depth soundings collected along random ship crossings of the South Pacific. Six years later the full extent of this chain was revealed by a radar altimeter aboard the Seasat (NASA) spacecraft. Recently, high density data collected by the Geosat (US Navy) and ERS-1 (European Space Agency) spacecraft data show the Pacific-Antarctic Rise and the Louisville Ridge in unprecedented detail... We are using these dense satellite altimeter measurements in combination with sparse measurements of seafloor depth to construct a uniform resolution map of the seafloor topography. These maps do not have sufficient accuracy and resolution to be used to assess navigational hazards but they are useful for such diverse applications as locating the obstructions/constrictions to the major ocean currents and locating shallow seamounts where fish and lobster are abundant.

4 posted on 03/28/2005 10:38:41 AM PST by SunkenCiv (last updated my FreeRepublic profile on Friday, March 25, 2005.)
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To: Ernest_at_the_Beach
"Probably wouldn't expose underwater seamounts though!"

I'm glad to see this article debunk the misconception that satellite radar surveys can't be used to map the general topography of the sea floor. There was much discussion of this on the numerous threads about the USS San Francisco grounding back in January. There were many techies that failed to grasp the concept that, just because the EM waves couldn't penetrate the ocean surface, that accurate sea height information could, nevertheless, be used to interpret the general state of the sea floor topography.

At minimum, there is enough info in the satellite radar data, that when compared with contemporary chart data, would provide a heads-up so that conventional sonar surveying ships, would know where their maps may be in error and where they should spend time doing a precise sea borne re-survey.

I hope that they follow up on the satellite data with both re-surveys and reprinting the charts (and not relying on Notice to Mariners).

--Boot Hill

8 posted on 03/28/2005 1:13:12 PM PST by Boot Hill ("...and Josuha went unto him and said: art thou for us, or for our adversaries?")
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