When the ceilometer was replaced, small gaps in the netCDF files occurred due to the
presence of '?' characters in the backscatter and header records of the raw data that could
not be ingested. It is unknown whether this was caused by a poor CPU board or
incompatibilities with the computer configuration (hyper-threading). The problem was corrected when
the instrument and computer were both replaced.
During this period, approximately 3% of data are missing each hour due to this problem.