SGP/RL - Raman lidar out of alignment

The Raman lidar was returned to service after a laser repair on 2/10/2000.
During normal instrument startup, the system attempts to optimize the 
alignment of the outgoing laser beam in the detector's field-of-view.
Occassionally, this routine fails to do this successfully, but subsequent
alignment "tweaks" (which typically occur every three hours) will usually
readjust the system and thus any periods of data related to poor alignment
are kept short.  However, shortly after system startup on the 10th, low
clouds moved in overhead which prevented the system from re-optimizing
itself.  To make matters worse, the system slowly drifted further out
of alignment, and thus when the sky conditions improved the system was
unable to correct its misalignment.  Site operations performed a restart
on Monday morning (2/14 around 1430 UT) which returned the lidar to its
nominal alignment.  Data from this period, especially the narrow field-of-
view data, will be greatly affected by this misalignment and probably 
should not be used.

No corrections possible.

• lon(lon)
• Number of photons counted in the low water vapor channel(water_counts_low)
• Number of photons counted in the high nitrogen channel(nitrogen_counts_high)
• Count rate in the high depolarization channel(depolarization_counts_high)
• Wavelength of each of the 6 filters measured by the MFR radiometers(filter)
• Number of photons counted in the high elastic (aerosol) channel(elastic_counts_high)
• Count rate in the high water vapor channel(water_counts_high)
• -180.0 - +180.0(alt)
• Time offset from base_time(time_offset)
• Laser pulse energy(pulse_energy)
• base time in epoch(base_time)
• North Latitude(lat)
• Nominal number of seconds of data acquired(acquisition_time)
• Number of photons counted in the low elastic (aerosol) channel(elastic_counts_low)
• Number of lidar pulses summed(shots_summed)
• Number of photons counted in the low nitrogen channel(nitrogen_counts_low)