Re: etopo high resolution files

["E. D. (Ned) Cokelet" <Edward.D.Cokelet@xxxxxxxx>]

A few months back I was looking into the best near-global bathymetric data set that I could find.  I settled on Smith and Sandwell v 8.2 .  Here's what I wrote about it then:   

Smith and Sandwell - This topography/bathymetry data set is gridded every 2 minutes at the equator and gets finer poleward using a 1/cos(latitude) grid spacing in latitude.  It is not global, but stops at about 70 N/70 S.  It is based on satellite-measured gravity anomalies with quality-controlled, ship-measured depths filtered in.  It is up to v. 8.2.  Previously PMEL Ferret has had v. 6.2 available.  I found a netcdf version of v. 8.2 from Univ. California at San Diego.  I got a copy and had it made available as the Smith and Sandwell Ferret data set at PMEL.  

ETOPO2 - This is a global topography/bathymetry data set.  It is Smith & Sandwell plus IBCAO in the Arctic plus others - all on a 2 minute x 2 minute equispaced, regular grid.  It was done by NOAA/NGDC, I think.  I got it on CDs, loaded their (buggy) software to read it, made it into an ASCII file, read it into Ferret, and wrote it out as a 2D netcdf file.  It occupies 233 MB of space.  Since it derives from Smith and Sandwell and is at lower resolution poleward, I prefer Smith and Sandwell v. 8.2.  

I do not know of a global or large-regional, 30-second bathymetry data set.  If you find one, I'd like to know more about it.  

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Edward D. (Ned) Cokelet, Ph.D.	Edward.D.Cokelet@noaa.gov
NOAA/PMEL					off: (206) 526-6820
7600 Sand Point Way NE			fax: (206 526-6485
Seattle, WA 98115-6439