Subject: Administrative: Update on GOES-12 (GOES-South America) Imager
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Topic: Update on GOES-12 (GOES-South America) Imager Electronics Side
Switch on June 6, 2012

Date/Time Issued: June 8, 2012 1830 UTC

Product(s) or Data Impacted: GOES-12 (GOES-South America) Imager Data

Date/Time of Initial Impact: June 6, 2012 1645 UTC

Date/Time of Expected End: N/A

Details/Specifics of Change: The GOES-12 Imager electronic side
switch was
completed as scheduled on June 6, 2012 at 1645 UTC.  The switch has
successfully improved the imagery and mitigated the cycle slip issue.
For
a review of the cycle slip issue, please visit the SSEC web site:
http://cimss.ssec.wisc.edu/goes/blog/archives/10528

During the GOES-12 imager side switch, the sounder ground system was
accidentally pointed to a wrong set of scan mirror emissivity
coefficients
which resulted in small errors in the broadcasted sounder data
between the
times of June 6, 2012 at 16:15 UTC to June 7, 2012 at 16:15 UTC.
Customers
should be aware of this data error; although, the errors did fall
within
specification.

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 was performed on Wednesday, June
6, 2012
during the 1615 UTC housekeeping period.  The operation took
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://cimss.ssec.wisc.edu/goes/rt/goessa.php for real-time
GOES-South
America Imagery
See
http://cimss.ssec.wisc.edu/goes/rt/viewdata.php?product=goessa_i4&time=latest&imageType=allanifor
imagery from the morning of June 7, 2012
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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<div><div><div>Topic: Update on GOES-12 (GOES-South America) Imager
Electro=
nics Side Switch on June 6, 2012</div><div><br></div><div>Date/Time
Issued:=
 June 8, 2012 1830 UTC=A0</div><div><br></div><div>Product(s) or
 Data Impac=
ted: GOES-12 (GOES-South America) Imager Data</div>

<div><br></div><div>Date/Time of Initial Impact: June 6, 2012 1645
UTC</div=
><div><br></div><div>Date/Time of Expected End:
N/A</div><div><br></div><di=
v>Details/Specifics of Change: The GOES-12 Imager electronic side
switch wa=
s completed as scheduled on June 6, 2012 at 1645 UTC. =A0The switch
has suc=
cessfully improved the imagery and mitigated the cycle slip
issue. =A0For a=
 review of the cycle slip issue, please visit the SSEC web
 site:=A0</div>

<div><a href=3D"http://cimss.ssec.wisc.edu/goes/blog/archives/10528"
target=
=3D"_blank">http://cimss.ssec.wisc.edu/goes/blog/archives/10528</a></div><d=
iv><br></div><div>During the GOES-12 imager side switch, the sounder
ground=
 system was accidentally pointed to a wrong set of scan mirror
 emissivity c=
oefficients which resulted in small errors in the broadcasted sounder
data =
between the times of June 6, 2012 at 16:15 UTC to June 7, 2012 at
16:15 UTC=
. =A0Customers should be aware of this data error; although, the
errors did=
 fall within specification.</div>

<div><br></div><div>The Office of Satellite and Product Operations
(OSPO) d=
ecided to switch the GOES-12 (GOES-South America) Imager electronics
side, =
based on the manufacturer&#39;s recommendation as a potential remedy
to mit=
igate cycle slips. =A0This side switch operation was performed on
Wednesday=
, June 6, 2012 during the 1615 UTC housekeeping period. =A0The
operation to=
ok approximately 30 minutes. =A0=A0</div>

<div><br></div><div>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 seri=
ous signs of aging. =A0In 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.=A0</div>

<div><br></div><div>A cycle slip is the shifting of a segment of the
image =
approximately 5.6 degrees (1 imager cycle) to the east or west. =A0It
occur=
s due because imager electronics lose count of the scan mirror
position. =
=A0These 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 an=
omaly at a later time. =A0Please see <a
href=3D"http://cimss.ssec.wisc.edu/=
goes/blog/archives/10307"
target=3D"_blank">http://cimss.ssec.wisc.edu/goes=
/blog/archives/10307</a> for an example.</div>

<div><br></div><div>Please note: Imager Side 2 electronics has a
different =
set of detectors, so users could use the new side-2 offline calibration
coe=
fficients and/or the new look-up table to convert GOES-12 Imager GVAR
data =
into brightness temperatures. =A0A new look-up table and calibration
coeffi=
cients for the side-2 detectors have been calculated and are available
on t=
he OSPO Calibration website: =A0<a
href=3D"http://www.oso.noaa.gov/goes/goe=
s-calibration/gvar-conversion.htm"
target=3D"_blank">http://www.oso.noaa.go=
v/goes/goes-calibration/gvar-conversion.htm</a></div>

<div><br></div><div>Please remember to use the new coefficients or
the look=
-up table after June 6, 2012 at 1615
UTC. =A0</div><div><br></div><div>ESPC=
 Operations contact information: =A0<a
 href=3D"mailto:ESPCOperations@noaa.g=
ov" target=3D"_blank">ESPCOperations@noaa.gov</a> and <a
href=3D"tel:301-81=
7-3880" value=3D"+13018173880" target=3D"_blank">301-817-3880</a></div>

<div><br></div><div>Web Site(s) for applicable
information:</div><div>See <=
a href=3D"http://www.ssd.noaa.gov/PS/SATS/messages.html"
target=3D"_blank">=
http://www.ssd.noaa.gov/PS/SATS/messages.html</a> =A0for this and
other sat=
ellite related messages.</div>

<div>See <a href=3D"http://www.ssd.noaa.gov/PS/SATS/GOES/SA/"
target=3D"_bl=
ank">http://www.ssd.noaa.gov/PS/SATS/GOES/SA/</a> for GOES-12
Information a=
nd Schedules=A0</div><div>See <a
href=3D"http://cimss.ssec.wisc.edu/goes/rt=
/goessa.php"
target=3D"_blank">http://cimss.ssec.wisc.edu/goes/rt/goessa.ph=
p</a> for real-time GOES-South America Imagery</div>

<div>See <a
href=3D"http://cimss.ssec.wisc.edu/goes/rt/viewdata.php?product=
=3Dgoessa_i4&amp;time=3Dlatest&amp;imageType=3Dallani"
target=3D"_blank">ht=
tp://cimss.ssec.wisc.edu/goes/rt/viewdata.php?product=3Dgoessa_i4&amp;time=
=3Dlatest&amp;imageType=3Dallani</a> for imagery from the morning of
June 7=
, 2012</div>

<div>See <a
href=3D"http://www.oso.noaa.gov/goes/goes-calibration/gvar-conv=
ersion.htm"
target=3D"_blank">http://www.oso.noaa.gov/goes/goes-calibration=
/gvar-conversion.htm</a> for new look-up table and calibration
coefficients=
</div>
<div>See <a
href=3D"http://www.oso.noaa.gov/goes/goes-calibration/goes-imag=
er-srfs.htm"
target=3D"_blank">http://www.oso.noaa.gov/goes/goes-calibratio=
n/goes-imager-srfs.htm</a> for side-2 Spectral Response Functions
(SRF)</di=
v>

<div>See <a
href=3D"http://cimss.ssec.wisc.edu/goes/blog/archives/10307" ta=
rget=3D"_blank">http://cimss.ssec.wisc.edu/goes/blog/archives/10307</a>
for=
 example of cycle slips</div></div>



</div>


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