On June 5, 2001, at 235900Z, the Satellite Operations Control Center
(SOCC) updated the NOAA-15 elapsed time clock to correct for the clock
drift. The SOCC correction was performed with no problems. However,
the preprocessing clock drift file was not updated properly. The
NOAA-15 clock error or along track error seen in images from the
Advanced Very High Resolution Radiometer (AVHRR) normally does not agree
with the
clock drift error reported by SOCC. As a result, the preprocessor file
must be
updated according to corrections that agree with the AVHRR observed
error rather than the SOCC reported error. For this particular update,
the SOCC
correction was used introducing an error in the level 1B data of
approximately a second for all passes processed for day 157 from 0000Z
through the passes below. This error affected all NOAA-15 instrument
level 1B earth location data and time codes.
NSS.GHRR.NK.D01157.S1754.E1939.B1593132.GC
NSS.HRPT.NK.D01157.S1940.E1953.B1593232.GC
We will endeavor to avoid problems such as this in the future.
Thanks for your patience.
Emily
--
*******************************************
*
* Emily D. Harrod
* NOAA/NESDIS/OSDPD/IPD
* Product Systems Branch
* Pre-Product Processing Group
* E/SP13, Federal Building #4, room 0318
* 5200 Auth Road
* Suitland, Maryland 20746-4304
* USA
* voice 301-457-5247
* fax 301-457-5199
* email Emily.Harrod@noaa.gov
*