CORRECTION TO LASER CEILOMETER CLOUD BASE ALTITUDE FILES (8th - 27th JANUARY
2010)
The Vaisala LD40 laser ceilometer developed an internal
fault at 20:48 UT on 3rd January 2010, which prevented it from making
observations. The problem cleared by itself at 21:42 UT on 4th January
but re-occurred at 00:29 UT on 8th January, lasting until 13:23 UT of
the same day. The cause of the problem is not known.
In connection with this problem, the LD40's internal clock, which is
used to generate the time stamps for the data messages, suddenly
jumped to from 13:23 UT to 03:05 UT on 8th January (the date stamp
subsequently became corrupted). This resulted in the time stamps being
in error in all cloud base altitude files, and their corresponding
quick look plots, 8th - 27th January 2010. This problem was corrected
in software on 29th January 2010 and all BADC files (and quick-look
plots) for the affected period have now been regenerated.
If you have made use of any of the cloud base altitude files from this
period, please contact the NERC MST
Radar Facility Project Scientist if you have any further
questions.
THE NERC MST RADAR FACILITY AT ABERYSTWYTH