NOAA-16 AVHRR Resynch > UPDATE 21 April 2004 ================================================ Topic: AVHRR Resynch to remove barcodes Date/Time(UTC) Message Issued: 21 April 2004 20:10 UTC Satellite(s) Involved: NOAA-16 Instrument(s) Involved: ALL Product(s) Involved/Affected: ALL/ Scan line dropout Date/Time(UTC) of Initial Implementation: 21 April 2004, 23:36 UTC Details/Specifics of Change: The MIRP rephase affects all instruments. Users should see scan line drop outs when the rephase occurs. Any user feedback on the improvement (or lack of) in AVHRR imagery following the rephase would be greatly appreciated. Thank you for your support. NOAA has reported re-occurance of the barcode pattern in the AVHRR imagery for NOAA-16. Once again a MIRP rephase will be required. The rephase will occur at the implementation time indicated above in this message. Users will see scan line drop outs when the rephase occurs. Checking "bit 1: resync occurred on this frame" in the data record quality indicators will tell you when the rephase occurs. "bit 29: data gap precedes this scan" indicates the gap created by the rephase in the scanline after it occurs. Contact Person(s) Name/Email/Phone Number for Questions: Emily Harrod emily.harrod@noaa.gov 30-457-5247 ext 117 Cecil Paris cecil.paris@noaa.gov 301-457-5247 ext 129 Web site(s) that contain other relevant information (where applicable): http://www.osdpd.noaa.gov/PSB/PPP/PPP.html - History of level 1B notices http://www.ssd.noaa.gov/PS/SATS/messages.html - All user notices http://www.oso.noaa.gov/poesstatus/ - SOCC polar satellites status http://www.oso.noaa.gov/daily-news/index.htm - SOCC morning reports ======================================================== Earlier Reports: ---------------- Topic: Scan Motor Current Anomaly Date/Time(UTC) Message Issued: 16 March 2004 , 1900 UTC Product(s) Involved/Affected: All products that use NOAA-16 AVHRR Date/Time(UTC) of Initial Implementation: 16 March 2004, 02:45 UTC (first time observed) Details/Specifics of Change: AT 02:45 UTC on 16 March 2004 it was observed that the scan motor current on the NOAA-16 has once again risen to an anomalous level causing problems for the AVHRR instrument. A bar code pattern for imagery was present at 10:30 Z, however this pattern was not present in an image taken at 12:30 Z. At present the anomalous level still exists and will be monitored for a return to nominal levels. Contact Person(s) Name/Email/Phone Number for Questions: Emily Harrod 301-457-5264 Web site(s) that contain other relevant information (where applicable): http://www.osdpd.noaa.gov/PSB/PPP/PPP.html - History of level 1B notices http://www.ssd.noaa.gov/PS/SATS/messages.html - All user notices http://www.oso.noaa.gov/poesstatus/ - SOCC polar satellites status http://www.oso.noaa.gov/daily-news/index.htm - SOCC morning reports ------------------------------------------------------------------------------------ 21 January 2004: The NOAA-16 AVHRR Temperature Control Electronics (TCE) 24 has been enabled since January 16; after three days operations, the instrument has stabilized with a temperature about 4 degrees lower on average (~21.0° C vs ~16° C). The scan motor current indicates a decreasing trend with slightly improved performance apparent at about 17.5° C (current orbital profile: 14.5° C to 17.5° C). The product and users' interface personnel of the IPD/CEMSCS reports that the images are are still usable, and we continue to get continuing assessments of the products. The resultant operations plan at this time is to leave the AVHRR in the current configuration with the TCE enabled with another tiger team meeting scheduled for January 22 with NASA and the instrument contractor, ITT. -------------------------------------------------- Topic: Cooling Scan Motor to Improve Performance Date/Time(UTC) Message Issued: 15 January 2004, 2245 UTC Satellite(s) Involved: NOAA-16 Instrument(s) Involved: AVHRR, HIRS Product(s) Involved/Affected: Possible improvement in AVHRR/May affect HIRS filter motor temperature Date/Time(UTC) of Initial Implementation: 16 January 2004, Time 1222 UTC Details/Specifics of Change: On January 16, around 1222, SOCC plans to turn the TCE-24 (Heater/Louver) back on. The AVHRR is running at record high temperatures. The scan motor surged to high values and imagery has degraded significantly (bar code pattern). It is believed that the scan motor operates better when cooler. Hince, the louver will be turned back on. We may see improvement in the AVHRR scan motor performance and probably a minor decrease in the HIRS filter motor temperature and current. Temperature may drop by 0.5 degrees and current by 2 to 4 mAmps over a day or two. ------------------------------------------------------------------------------------- On September 26, SOCC reported the following: "The NOAA-16 AVHRR/MIRP resynch commands are now incorporated into the stored command table and are executed at 0430z daily. On September 23, TCE24 (AVHRR Heater/Louver) was turned off in an attempt to raise the temperature of the local area around the AVHRR in an attempt to recover additional lubricant for the scan motor. The AVHRR scan motor has stabilized at a new temperature less than 5 degrees higher than the previous steady state. Over the last 24 hours the AVHRR performance appears nominal, although it continues to be carefully monitored." ------------------------------------------------------------------------------------- On September 23 (day 266) on orbit 15478 around 1356 UTC, the Satellite Operations Control Center (SOCC) will "turn off the TCE24 (AVHRR Heater/Louver). This will be done in an attempt to heat up the AVHRR and decrease the viscosity of the scan motor lubricant. The current thought is that the lubricant has become too cold and thick reducing lubrication and that heating up this lubrication will have the reverse effect. This was shown to have worked on NOAA-12 10 years ago." SOCC will continue to enable rephasing about twice a day or as needed. However, plans are to automate rephasing once per day during the blind orbit (around 0430 UTC) beginning on September 26. Users will be notified of any changes. -------------------------------------------------------------------------------------- At approximately 07:00 UTC on 17 Sept, the N16 AVHRR scan motor current and its synch delta word began to act erratically running up as high as 287 mAmps (vs nominal 230). As of this writing, it has not returned to a nominal performance profile. Engineers are making every attempt to maintain data quality and are currently reviewing potential actions to correct the problem. The following immediate plans are to disable automatic rephasing to minimize the loss of data. Controllers will then enable rephasing once per 12 hour shift (on the first available contact per shift that time permits). Operational impacts are: 1) each time rephasing occurs there will be a drop in TIP frames (1 or 2 frames) and 2) the pointing of the AVHRR may not be as accurate in between times to rephase. Rephase will only occur if needed during the time it is enabled as mentioned above. ---------------------------------------------------------- Posted to the NOAASIS 1900 UTC 21 April 2004