1997_avhrr_data
</h1>
<pre>
	PI:		J. J. Bisagni
	Dataset:	Satellite-derived AVHRR SST images
	
</pre>


<h2>AVHRR SST Images</h2>

 	Satellite-derived AVHRR SST images for the
 	US-GLOBEC Georges Bank Program study domain,
 	39.013-45.429 deg N latitude, 63.487-72.164 deg W longitude,
 	1 October 1993-present day.
 
 <h2>	Data Provider</h2>
<address>
 	Dr. J. J. Bisagni/
 	NOAA/NMFS/
 	28 Tarzwell Drive/
 	Narragansett, RI 02882/
 	bisagni@fish1.gso.uri.edu/
 	(401) 782-3313
</address> 

 <h2>	Notes</h2>
<ul>
 	<li>Images are 512 X 512 pixels, possess a resolution of 1.4 km
 	and are displayed as .GIF images.</li>
 
 	<li>The archive "switches" from NOAA-11 to NOAA-9 during
 	September 1994 due to the NOAA-11 failure in September 1994.</li>
 
 	<li>At present, all NOAA-9, -12 and -14 overpasses are remapped
 	to the above domain and added to the archive on a daily basis.</li>
 
 	<li>At the end of each month, all the month's images 
 	are precision navigated to within 1-2 pixels (1.4-2.8 km).
 	NOAA-12 and -14 data are then saved to tape and deleted,
 	due to calibration problems with NOAA-12 and -14 and to
 	conserve disk space.</li>
 
 	<li>Images from the current month may possess navigation errors of
 	up to 3-5 pixels or more in the X and/or Y directions.</li>
</ul>


<h2> Additional Information About Image Processing</h2>

<p>At the present time all daily NOAA-11 Advanced Very High 
Resolution Radiometer satellite passes from 1 October 1993 up to the 
present day (generally 2 passes per day) have been remapped 
(earth-located) to our Georges Bank/Gulf of Maine "standard" region 
(given below) in a Mercator projectio. Our standard region 
is bounded by:
<ul>
	<li>39.013 - 45.429 deg N latitude, and </li>
	<li>63.487 - 72.164 deg W longitude.</li>
</ul>

<p>Precision navigation of each image  to within 1 or 2 
pixels has begun with the image file names receiving a ".nav" file 
extension when navigation is completed. Be aware that "un-
navigated" images (".rmp" file extension) may possess navigation 
errors of up to 6 or 7 pixels in the meridional and/or zonal 
directions.  Note that only ".nav" files are being served here
at this time.

<p>Daily remapping and weekly backups of these data will 
continue until after completion of the GLOBEC and Gulf of Maine field 
programs are completed. Each of these images are in University of 
Miami XDR04 format, consisting of an 8-bit, 512 X 512 pixel binary 
image, preceded by three 512-byte header records. The size of each 
image file (in uncompressed form) is ~250K bytes.

<p>These images are uncompressed and converted from Xbrowse to gif
images for display by your favorite browser, such as Mosaic or Netscape.


<H3> XBrowse Software </h3>

<p>Near real-time, daily, satellite-derived sea surface temperature
(SST) data, which cover Georges Bank and the Gulf of Maine  are also
available for browsing over the Internet in the Xbrowse format.
This browse capability is being made available via the Xbrowse
(X-window based) client/server system developed by Jim Gallagher
(jimg@dcz.gso.uri.edu) in Peter Cornillon's group located at the
University of Rhode Island's Graduate School of Oceanography. In
addition to visual "browsing" of the data, the Xbrowse system also
allows the names of user-selected images to be listed in a file on your
local host for later use in retrieving those images from the Xbrowse
server via ftp.
  

<p>The latest Xbrowse client (ver. 3.3.7) and accessory files are 
available for SunOS 4.1.3 (Sun SPARC), OSF 1.3 (DEC Alpha) and Ultrix 
4.3 (DECstation) via anonymous ftp from zeno.gso.uri.edu 
(/pub/xbrowse) and must be uncompressed, restored (via "tar") and 
properly installed on your local host for the system to work.


<p>Assuming that the client is properly installed on your local 
host, you can start the remote server by typing:
	<b>xbrowse -server dcz.gso.uri.edu  </b>

<p>Those of you who have an earlier version of Xbrowse and would like 
access to the server should get an update because the latest version 
handles the Mercator projection properly.

<h3>Downloading the image</h3>

<p>You can capture the gif image if your browser has that capability.  In
addtion, if you would like to download any of the Xbrowse images over the 
network to your local host for your own use, please contact me or 
Carl Wolfteich (carlw@chips1.gso.uri.edu) directly.
1997_avhrr_data