Subject: Administrative: GOES-12 (GOES-South America) Imager
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Topic: GOES-12 (GOES-South America) Imager Electronics Side Swap is
scheduled for June 6, 2012
Date/Time Issued: June 1, 2012 1800 UTC
Product(s) or Data Impacted: GOES-12 (GOES-South America) Imager Data
Date/Time of Initial Impact: June 6, 2012 1615 UTC
Date/Time of Expected End: June 6, 2012 1645 UTC
Length of Outage: 30 minutes
Details/Specifics of Change: The Office of Satellite and Product
Operations
(OSPO) decided to switch the GOES-12 (GOES-South America) Imager
electronics side, based on the manufacturer's recommendation as
a potential
remedy to mitigate cycle slips. This side switch operation will be
performed on Wednesday, June 6, 2012 during the 1615 UTC housekeeping
period. The operation is expected to take approximately 30 minutes.
GOES-12 (GOES-South America) had a 5-year expected life span, but
it has
been in service for more than 9 years and is showing serious signs of
aging. In late April 2012, imager cycle slips increased to daily
occurrences, corrupting on average 3-5 frames every day and spreading
to
15-20 frames per day during the past week.
A cycle slip is the shifting of a segment of the image approximately
5.6
degrees (1 imager cycle) to the east or west. It occurs due because
imager
electronics lose count of the scan mirror position. These segment
shifts
can happen more than once in the same image as the instrument corrects
itself during a space look and then repeats the same anomaly at a later
time. Please see http://cimss.ssec.wisc.edu/goes/blog/archives/10307
for
an example.
Please note: Imager Side 2 electronics has a different set of
detectors,
so users could use the new side-2 offline calibration coefficients
and/or
the new look-up table to convert GOES-12 Imager GVAR data into
brightness
temperatures. A new look-up table and calibration coefficients for the
side-2 detectors have been calculated and are available on the OSPO
Calibration website:
http://www.oso.noaa.gov/goes/goes-calibration/gvar-conversion.htm
Please remember to use the new coefficients or the look-up table
after June
6, 2012 at 1615 UTC.
ESPC Operations contact information: ESPCOperations@noaa.gov and
301-817-3880
Web Site(s) for applicable information:
See http://www.ssd.noaa.gov/PS/SATS/messages.html for this and other
satellite related messages.
See http://www.ssd.noaa.gov/PS/SATS/GOES/SA/ for GOES-12 Information
and
Schedules
See http://www.oso.noaa.gov/goes/goes-calibration/gvar-conversion.htm
for
new look-up table and calibration coefficients
See http://www.oso.noaa.gov/goes/goes-calibration/goes-imager-srfs.htm
for
side-2 Spectral Response Functions (SRF)
See http://cimss.ssec.wisc.edu/goes/blog/archives/10307 for example of
cycle slips
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