avhrr_1998

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

AVHRR SST Images

39.013 - 45.429 degree North latitude, 63.487 - 72.164 degree West longitude,

1 October 1993 - 2003.

Data Provider

Field Name Descriptions

Field Name	Description
Images	Satellite number
Description	Description of satellite
Contributor	Name of contributor providing the image(s)
month	Month, with 1 meaning January when image was taken (UTC)
year	Year when image was taken (UTC)
status	Status of image, e.g. unprocessed, unnavigated, navigated
yrday_utd	Year day image was taken, with 1 being January 1 (UTC)
day	Day of the month image was taken (UTC)
time	Time of day image was taken (UTC)

Summary of Satellites Availabe, by Year

Year	Satellite
1993	NOAA-11
1994	NOAA-11 (January - September), NOAA-9 (September - December)
1995	NOAA-11, NOAA-9
1996	NOAA-14
1997	NOAA-14
1998	NOAA-14
1999	NOAA-14, NOAA-15 (starting in December)
2000	NOAA-14, NOAA-15 (January - July), NOAA-16 (October - December)
2001	NOAA-14 (mostly bad, use NOAA-15), NOAA-15 (October - December), NOAA-16
2002	NOAA-14 (still mostly bad, use NOAA-15), NOAA-15, NOAA-16

Notes

• The image aspect ratio is now correct. The images should be square. This problem within the IDL engine was solved November 2007 by switching to the ferret application to generate the images.
• 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.
• Starting in 1994, 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.
• During the initial data acquisition time, images from the current month may possessed navigation errors of up to 3-5 pixels or more in the X and/or Y directions.
• Starting August 2002, images from NOAA-17 ("b") became available. They seem to have replaced the NOAA-14 ("f") images.
• The colorbar used is derived from so-called Pete's Palette, or pete24, and converted to an equivalent palette in the ferret scheme. (See petespalette.spk.

Additional Information About Image Processing

At the present time all daily NOAA-11 Advanced Very High Resolution Radiometer satellite passes from 1 October 1993 on (generally 2 passes per day) have been remapped (earth-located) to our Georges Bank/Gulf of Maine "standard" region (given below) in a Mercator projection. Our standard region is bounded by:

• 39.013 - 45.429 degree North latitude, and
• 63.487 - 72.164 degree West 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 via the ferret application for display by your favorite browser, such as Internet Explorer, Mozilla, and Firefox.

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. http://dcz.gso.uri.edu/avhrr-archive/archive.html

The latest Xbrowse client (ver. 3.3.7) and accessory files used to be 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 had to be uncompressed, restored (via "tar") and properly installed on your local host for the system to work. You might be able to get help by contacting the datamaster at GSO/URI at datamaster@mail.po.gso.uri.edu.

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.

DODS System

Downloading the image

You can capture the gif image if your browser has that capability. In addition, 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 directly.

This document is created from the content of the info file.