CGMS-41 NOAA-WP-11
Prepared by
N. Sun, F. Yu and F. Weng
Agenda Item: II/2
Discussed in WG-II
NOAA REPORT ON SATELLITE CALIBRATION ANOMALIES
AND SIGNIFICANT INSTRUMENT EVENTS
NOAA Integrated Calibration and Validation System (ICVS) continues evolved for
the monitoring of instrument performance and radiance quality of the NOAA
operational satellite instruments. It continues playing a key role in detecting the
calibration anomaly, diagnosing the root cause and assessing the impacts of
anomalous events. This report summarizes the significant instrument events and
calibration anomalies detected and assessed with the NOAA ICVS in the past one
year.
CGMS-41 NOAA-WP-11
NOAA Report on Satellite Calibration Anomalies
1
Introduction
To meet the increasing demand for high-quality of radiance data from the user
community, a satellite instrument integrated calibration and validation system (ICVS)
with a web interface has been developed at NOAA National Environmental Satellite,
Data and Information Service (NESDIS), Center for Satellite Applications and Research
(STAR). The development of this web-based system has been evolved aiming to
provide instrument scientists with calibration healthy status and users with the
information regarding the satellite data quality for product generation. It can also
facilitate the communication of instrument anomalies amongst instrument and
calibration scientists and user community. Therefore, this system focuses on the longterm monitoring of real-time on-orbit instrument performance and sensor data product
quality. While the performance of calibration related parameters are monitored with the
instrument performance long-term monitoring (LTM) suite, the sensor data record
(SDR) quality monitoring is enriched with the inter-calibrations and/or inter-comparisons
of the Global Space-based Inter-Calibration System (GSICS) which is operating under
the auspices of the World Meteorological Organization (WMO). With the instrument
performance and data monitoring systems, the ICVS-LTM can not only detect the
calibration anomalies, but also help to diagnose the root causes and develop correction
algorithm improve the calibration accuracy. Followings are the report of calibration
anomalies which were detected, assessed and improved, if possible, with the STAR
ICVS-LTM system in the past one year.
2
Satellite Calibration Anomalies
2.1 SNPP ATMS
Suomi National Polar-orbiting Partnership (SNPP) was successfully launched
on October 28, 2011. STAR ICVS-LTM started real time monitoring of SNPP
spacecraft and sensor health status and performance since November 1, 2011 when
operational datasets were available. After early orbit checkout (EOC) and intensive
cal/val (ICV), all sensors were stabilized and started to providing valid SDR for
calibration and validation. Advanced Technology Microwave Suite (ATMS)
temperature data record (TDR) is the very first sensor data that was announced
operational in NOAA/NCEP and widely evaluated and tested in other NWP centers,
such as UKMO and ECMWF. The sensitivities (NE∆Ts) of all 22 channels meet the
instrument requirements with a margin and are quite stable. The only ATMS anomaly
detected by STAR ICVS-LTM system and acknowledged by instrument scientists is
the scan drive main motor current anomaly between October and December 2012. It
Page 1 of 15
CGMS-41 NOAA-WP-11
didn’t affect the sensor data quality, but caused variations in ATMS field-of-view
(FOV) angles, which are shown in Figure 1.
Figure 1. SNPP ATMS (a) scan drive main motor current and (b) earth FOV #1 angle
LTM trending since launch
For other sensors, such as CrIS, VIIRS, and OMPS, STAR will be waiting until
they are declared to be operational to provide the calibration anomaly report to CGMS.
2.2 AMSU/MHS
NOAA-19 AMSU-A
From end of 2012, the NE∆T of NOAA-19 AMSU-A Channel 7 showed a faster
increasing trend out of specification. It is also detected that both warm load count and
space view count increased faster simultaneously. The root cause of such increasing
is still under investigation. However, the A1-1 antenna drive motor current presented
the larger than usual variation almost at the same time in ICVS-LTM system, as
shown in Figure 2
Page 2 of 15
CGMS-41 NOAA-WP-11
Figure 2. NOAA-19 AMSU-A Channel 7 LTM trending of (a) NE∆T, (b) Warm Load
Count, (c) Space View Count, (d) A1-1 Antenna Drive Motor Current
Page 3 of 15
CGMS-41 NOAA-WP-11
NOAA-19 AMSU-A channel 8 NE∆T was out of specification at end of year 2009. It
keeps quite stable until second half of year 2012, when large variation was detected. The
associated warm load count and space view count LTM trending are also shown in figure 3.
Figure 3. NOAA-19 AMSU-A Channel 8 LTM trending of (a) NE∆T (b) Warm Load
Count (c) Space View Count
MetOp-A AMSU-A
MetOp-A AMSU-A channel 3 NE∆T experienced increasing trend from end of
year 2010. Since then, it kept its increasing rate and went out of specification in
Page 4 of 15
CGMS-41 NOAA-WP-11
March 2013, as shown in figure 4. STAR ICVS-LTM system will keep watching the
status and report to community if any change happens at this channel.
Figure 4. MetOp-A AMSU-A Channel 3 LTM trending of NE∆T
NOAA-18 AMSU-A
NOAA-18 AMSU-A channel 8 NE∆T has showed out-of-specification status
occasionally since year 2010, as shown in figure 5. A large antenna drive motor
current of A1-2, where channel 8 is located, was also presented in the ICVS-LTM
system.
Page 5 of 15
CGMS-41 NOAA-WP-11
Figure 5. NOAA-18 AMSU-A Channel 8 LTM trending of (a) NE∆T and (b) A1-2
antenna drive motor current
NOAA-19 MHS
NOAA-19 MHS channel 3 NE∆T got a sudden jump in year 2009. After
adjustment at the end of 2009, NE∆T of this channel kept very stable even the value
is out of the specification. Both warm load count and space view count are quite
stable too.
Page 6 of 15
CGMS-41 NOAA-WP-11
Figure 6. NOAA-19 MHS Channel 3 LTM trending of (a) NE∆T (b) Warm Load Count
(c) Space View Count
2.3 AVHRR
NOAA-18 AVHRR
The noise performance is characterized using Signal-to-Noise Ratio (SNR) for
visible channels and Noise Equivalent differential Temperature (NEdT) for IR
channels. NOAA-18 channel 1 SNR has showed some out-of-specification values
since last year, as shown in figure 7. STAR ICVS-LTM system will keep watching the
trend of this channel and report to CGMS any change in the future.
Figure 7. NOAA-18 AVHRR Channel 1 LTM trending of SNR
2.4 HIRS
NOAA-19 HIRS
NOAA-19 HIRS NE∆N of channel 5 and 10 went out of specification in year
2012. HIRS calibration scientists are working on the analysis of both channels.
Page 7 of 15
CGMS-41 NOAA-WP-11
Figure 8 NOAA-19 HIRS NE∆T LTM trending of (a) Channel 5 and (b) Channel 10
MetOp-B HIRS
MetOp-B HIRS NE∆N of channel 5, 6, 7, and 10 showed noticeable variation
and went out of specifications in April, 2013. Shown in figure 9 are the NE∆N LTM of
those channels since the activation of HIRS in October 2012. Due to the change from
full orbit to half orbit data distribution method, ICVS-LTM for HIRS needs to be
update to handle such change to make more accurate monitoring.
Page 8 of 15
CGMS-41 NOAA-WP-11
Figure 9. MetOp-B HIRS NE∆T LTM trending of (a) Channel 5, (b) Channel 6, (c)
Channel 7, and (d) Channel 10
NOAA-18 HIRS
NOAA-18 HIRS NE∆N of channel 2, 4, 5, 6, 7, 9, and 10 went out of
specification for a good period of time and demonstrated significant variation during
the entire mission. Shown in figure 10 is channel 5 NE∆N LTM trending for the entire
mission.
Page 9 of 15
CGMS-41 NOAA-WP-11
Figure 10. NOAA-18 HIRS NE∆T LTM trending of Channel 5
2.5 GOES
GOES-13 Sounder Filter Wheel Anomaly
An anomaly of GOES-13 Sounder Filter Wheel (FW) occurred on 20 June 2012,
resulting in abnormal change of instrument background thermal environment at
GOES-13 Sounder IR channels. The STAR GOES Instrument Performance
Monitoring System (IPMS) detected the rapid changes of calibration coefficients and
other calibration parameters caused by the FW anomaly (Figure 1, left). However,
the data quality monitoring using the GSICS GEO-GEO inter-comparison technique
showed that the event impact on radiances lasted for about four days and was most
apparent at the long-wave (LW) channels (Figure 11, right). Following-on discussion
with the instrument calibration engineers found the four-day duration impact was
caused by the smoothing of the erratic calibration coefficients. As a result, the
calibration mode was changed during the solstice period.
Figure 11. Impacts of GOES-13 Sounder FW anomaly on the long wavelength
Ch14.71µm as an example, detected by GOES IPMS (left) and GSICS GEO-GEO
monitoring (right).
Page 10 of 15
CGMS-41 NOAA-WP-11
Increasing GOES-13 Sounder Infrared Short-Wave (SW) Noise and Instrument
Shutdown
GOES-13 Sounder SW IR channels experiences an increasing noise since
mid-July 2012. The elevated noise jumped suddenly in late August 2012 (Figure 12)
and keeps increasing. On 23 September 2012 at 11:26z, GOES-13 Sounder was
shutdown. ITT investigated the root cause to the increasing noise and shutdown
event were caused by the filter wheel anomaly.
Figure 12. The mean NEdT@286K of GOES-13 Sounder IR channels since January
2012. The red line is the specifications at each IR channel.
GOES-13 Imager shutdown
Page 11 of 15
CGMS-41 NOAA-WP-11
GOES-13 Imager was shut down on 23 September 2012 at 21:21z. The root
cause is also related to the Sounder filter wheel anomaly. The GOES-IPMS caught up
the changes of instrument noise at space view scans as shown in Figure 13. The
patterns and durations of the noise variations are valuable to understand the impact on
products.
Figure 13. Time-series of instrument noise at space view scan (after space clamp) at
GOES-13 Imager Ch3 (6.5µm), showing the increasing noise at certain time of day
since mid-Sept. 2012. The monitoring stopped around 21:00z-22:00z on 23 September
2012 as the instrument shutdown.
GOES-13 Imager and Sounder Instrument Recovery
GOES-13 Imager and Sounder were anomalous shutdown on September 23,
2012. Root cause investigation by the instrument engineers showed that this event
was due to the Sounder filter wheel subsystem anomalous performance. After a
change of the Sounder electronic system and outgassing, tests were scheduled to
evaluate the GOES-13 data quality. The GOES IPM system played a critical role in
monitoring detector noise and overall radiance quality during the recovery tests. Our
radiance quality evaluations showed no apparently large change in the overall
radiance accuracy after the instrumented-on and the change of Sounder electronics
Page 12 of 15
CGMS-41 NOAA-WP-11
(Figure 14). Compared to data before the anomaly, the Sounder detector noise and
coherent noise are greatly reduced (Figure 15).
Figure 14. Example of GOES-13 vs. GOES15 inter-comparison for Sounder 1
(14.71µm), showing no apparent large changes of overall radiometric calibration
accuracy at GOES-13 Sounder infrared channels after the instrument returned-on
and the Sounder outgassing event.
Figure 15. Reduced Imager coherent noise after instrument turn-on (left) and
reduced sounder detector noise (right) after the Sounder outgassing event.
3
SUMMARY
The NOAA/NESDIS/STAR ICVS-LTM system is evolved with more functions to
long-term monitoring of real-time calibration related instrument parameters and
radiance quality. The later component is enriched with the GSICS inter-calibration and
Page 13 of 15
CGMS-41 NOAA-WP-11
inter-comparison monitoring. This report focuses on the radiometric calibration
anomalies which were detected, assessed and remedied, if possible with the
NOAA/NESDIS/STAR ICVS-LTM system from 2012-2013.
New instrument anomaly or update events in 2012-2013:
 SNPP ATMS scan drive main motor current anomaly;
 NOAA-19 AMSU-A Channel 7 and Channel 8 NEΔT went out of specification;
 MetOp-A AMSU-A Channel 3 NEΔT went out of specification;
 NOAA-18 AMSU-A Channel 8 NEΔT went out of specification;
 NOAA-19 MHS Channel 3 NEΔT kept out of specification;
 NOAA-18 AVHRR Channel 1 SNR went out of specification;
 NOAA-19 HIRS Channel 5 and 10 went out of specification;
 MetOp-B HIRS Channel 5, 6, 7, and 10 went out of specification;
 NOAA-18 HIRS Channel 2, 4, 5, 6, 7, 9, and 10 went out of specification;
 GOES-15 replaced GOES-11 as the GOES-West on 5 December 2011, with
STAR ICVS corrected SRFs to improve the radiometric calibration accuracy of
GOES-15 Imager Ch3 and Ch6.
 GOES-13 Sounder IR channels, especially the LW channels, experienced
radiometric calibration anomaly from 20 June 2012 – 24 June 2012.
 The noise of GOES-13 Sounder SW increased in mid-June and beyond
specifications since then. Root cause to this anomaly is unknown yet.
 GOES-13 Imager and Sounder were shutdown on 23 September 2012. Root
causes are under investigation.
 GOES-12 Imager IR channels experienced radiometric calibration anomaly from
~19:30z 2 December 2012 to ~15:00z 13 Decestigation.
Page 14 of 15