1996_avhrr_data

	PI:		J. J. Bisagni
	Dataset:	Satellite-derived AVHRR SST images
	

AVHRR SST Images

Data Provider

Notes

• Images are 512 X 512 pixels, possess a resolution of 1.4 km and are displayed as .GIF images.
• The archive "switches" from NOAA-11 to NOAA-9 during September 1994 due to the NOAA-11 failure in September 1994.
• At present, all NOAA-9, -12 and -14 overpasses are remapped to the above domain and added to the archive on a daily basis.
• 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.
• Images from the current month may possess navigation errors of up to 3-5 pixels or more in the X and/or Y directions.

Additional Information About Image Processing

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:

• 39.013 - 45.429 deg N latitude, and
• 63.487 - 72.164 deg W longitude.

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.

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.

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

XBrowse Software

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.

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.

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

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.

Downloading the image

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.