TWP/MPl/C2 - Laser power failure events

When the new laser for the MPL at Nauru was installed the handset was incorrectly set to
manual instead of automatic. This meant that when the power was interrupted to the I van 
(even

observers when they saw no laser light. This went on from 29 Jan at 23:00

• Aerosol backscatter coefficient at 355 nm(backscatter)

TWP/MPL/C2 - Power outage in I-Van resulted in Missing Data

I forgot to put in the daily report that we took the I van down yesterday to replace the 
fans
in the Clary UPS. This was from 2300z on 24May03 to 0010z on 25May03. Instruments affected 
:

MPL
Ceilometer
MWR
WSI
TSI

Rex

• Time offset of tweaks from base_time(time_offset)
• base time(base_time)
• MPL Cloth et al. Algorithm Significance Mask(SigniMaskMplCloth)
• Height of Center of Each Range Bin(Heights)

• null(Raw data stream - documentation not supported)

• time(time)
• Laser Temperature(laser_temp)
• Repetition rate, or Trigger Frequency of the laser(trigger_freq)
• Maximum altitude retrieved from multichannel scalar card.(max_altitude)
• Sum of raw backscatter counts per bin prior to ANY corrections.(total_counts)
• Time in nanoseconds for each range bin of multichannel scalar card.(range_bin_time)
• Angle of inclination with respect to horizontal(transceiver_altitude_angle)
• Background Signal(background_signal)
• Laser output energy per pulse(energy_monitor)
• Number of laser shots recorded(shots_summed)
• Angle of orientation with respect to true geographic north(transceiver_azimuth_angle)
• Voltage level which operates the A/D card and the detector(voltage_05)
• Amount of time laser pulse lags behind the scalar trigger(laser_scalar_sync_offset)
• Time offset of tweaks from base_time(time_offset)
• Voltage level which operates the thermistor(voltage_10)
• lon(lon)
• base time(base_time)
• lat(lat)
• Width of range-bins calculated from range_bin_time(range_bin_width)
• Dummy altitude for Zeb(alt)
• required to correct raw counts for detector deadtime prior to all other
  corrections.(deadtime_correction)
• Amount of time the scalar lags behind the sync trigger(scalar_sync_offset)
• Distance from leading edge of first range bin to the center of each bin .(range_bins)
• Aerosol backscatter coefficient at 355 nm(backscatter)
• Preliminary cloud base height(preliminary_cbh)
• Number of laser pulses summed during measurement interval(shots_sum)
• Array of heights for the range gates(height)
• Detector Temperature(detector_temp)
• Instrument Temperature(instrument_temp)
• range(range)
• Repetition Rate, or Trigger Frequency of the laser(pulse_rep)
• Voltage level which operates the energy monitor(voltage_15)
• Filter Temperature(filter_temp)
• effective range offset due to poor sync between laser firing and A/D trigger.(range_offset)
• value represents date of last configuration change as yyyymmdd(property)
• Amount of time the actual laser pulse lags behind the sync trigger(laser_sync_offset)

• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)
• Height of Center of Each Range Bin(Heights)
• base time(base_time)
• Time offset of tweaks from base_time(time_offset)

TWP/MPL/C2 - Sun-shade dropping during daytime

The MPL sunshade began to act erratically on 9/15/2003 dropping frequently throughout day 
and night.  To reduce data loss, the sunshade was restrained from blocking the MPL during 
the night.  Thus, cloud detection during the night is satisfactory, but daytime 
measurements are frequently interspersed with episodes of beam-block.

• Time offset of tweaks from base_time(time_offset)
• base time(base_time)
• MPL Cloth et al. Algorithm Significance Mask(SigniMaskMplCloth)
• Height of Center of Each Range Bin(Heights)

• null(Raw data stream - documentation not supported)

• time(time)
• Laser Temperature(laser_temp)
• Repetition rate, or Trigger Frequency of the laser(trigger_freq)
• Maximum altitude retrieved from multichannel scalar card.(max_altitude)
• Sum of raw backscatter counts per bin prior to ANY corrections.(total_counts)
• Time in nanoseconds for each range bin of multichannel scalar card.(range_bin_time)
• Angle of inclination with respect to horizontal(transceiver_altitude_angle)
• Background Signal(background_signal)
• Laser output energy per pulse(energy_monitor)
• Number of laser shots recorded(shots_summed)
• Angle of orientation with respect to true geographic north(transceiver_azimuth_angle)
• Voltage level which operates the A/D card and the detector(voltage_05)
• Amount of time laser pulse lags behind the scalar trigger(laser_scalar_sync_offset)
• Time offset of tweaks from base_time(time_offset)
• Voltage level which operates the thermistor(voltage_10)
• lon(lon)
• base time(base_time)
• lat(lat)
• Width of range-bins calculated from range_bin_time(range_bin_width)
• Dummy altitude for Zeb(alt)
• required to correct raw counts for detector deadtime prior to all other
  corrections.(deadtime_correction)
• Amount of time the scalar lags behind the sync trigger(scalar_sync_offset)
• Distance from leading edge of first range bin to the center of each bin .(range_bins)
• Aerosol backscatter coefficient at 355 nm(backscatter)
• Preliminary cloud base height(preliminary_cbh)
• Number of laser pulses summed during measurement interval(shots_sum)
• Array of heights for the range gates(height)
• Detector Temperature(detector_temp)
• Instrument Temperature(instrument_temp)
• range(range)
• Repetition Rate, or Trigger Frequency of the laser(pulse_rep)
• Voltage level which operates the energy monitor(voltage_15)
• Filter Temperature(filter_temp)
• effective range offset due to poor sync between laser firing and A/D trigger.(range_offset)
• value represents date of last configuration change as yyyymmdd(property)
• Amount of time the actual laser pulse lags behind the sync trigger(laser_sync_offset)

• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)
• Height of Center of Each Range Bin(Heights)
• base time(base_time)
• Time offset of tweaks from base_time(time_offset)

TWP/MPL/C1 - SunShade timing problem

For an unknown reason, the sun shade was dropping for less then 10 minutes during the 
night at about 19:00 UTC between Dec 14, 2003 and Feb 17, 2004.  Data taken during that ten 
minute interval is not looking at the sky and should be considered as though it were 
missing.

This is a fairly small effect.  Data users can simply average across the interval or block 
the records as "missing".

• Laser Temperature(laser_temp)
• Aerosol backscatter coefficient at 355 nm(backscatter)
• Filter Temperature(filter_temp)
• Background Signal(background_signal)
• Detector Temperature(detector_temp)
• Dummy altitude for Zeb(alt)
• GPS raw data filename(filename)
• lon(lon)
• Time offset of tweaks from base_time(time_offset)
• Voltage level which operates the A_D card and the detector(voltage_5)
• Voltage level which operates the thermistor(voltage_10)
• Preliminary cloud base height above ground level(cbh)
• Number of laser shots recorded(shots_summed)
• Instrument Temperature(instrument_temp)
• Repetition Rate, or Trigger Frequency of the laser(pulse_rep)
• base time(base_time)
• Laser output energy per pulse(energy_monitor)
• Voltage level which operates the energy monitor(voltage_15)
• lat(lat)

• null(Raw data stream - documentation not supported)

• Height of Center of Each Range Bin(Heights)
• MPL Cloth et al. Algorithm Significance Mask(SigniMaskMplCloth)
• Time offset of tweaks from base_time(time_offset)
• base time(base_time)

• base time(base_time)
• Time offset of tweaks from base_time(time_offset)
• Height of Center of Each Range Bin(Heights)
• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)

TWP/MPL/C1 - SP laser diode supply failed

The Spectra Physics laser diode supply failed on March 2, 2004.  A replacement was 
installed April 18. 

Any data between these dates is worthless.

• Laser Temperature(laser_temp)
• Aerosol backscatter coefficient at 355 nm(backscatter)
• Filter Temperature(filter_temp)
• Background Signal(background_signal)
• Detector Temperature(detector_temp)
• Dummy altitude for Zeb(alt)
• GPS raw data filename(filename)
• lon(lon)
• Time offset of tweaks from base_time(time_offset)
• Voltage level which operates the A_D card and the detector(voltage_5)
• Voltage level which operates the thermistor(voltage_10)
• Preliminary cloud base height above ground level(cbh)
• Number of laser shots recorded(shots_summed)
• Instrument Temperature(instrument_temp)
• Repetition Rate, or Trigger Frequency of the laser(pulse_rep)
• base time(base_time)
• Laser output energy per pulse(energy_monitor)
• Voltage level which operates the energy monitor(voltage_15)
• lat(lat)

• null(Raw data stream - documentation not supported)

• Height of Center of Each Range Bin(Heights)
• MPL Cloth et al. Algorithm Significance Mask(SigniMaskMplCloth)
• Time offset of tweaks from base_time(time_offset)
• base time(base_time)

• base time(base_time)
• Time offset of tweaks from base_time(time_offset)
• Height of Center of Each Range Bin(Heights)
• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)

TWP/MPL/C1 - Reprocess: Global metadata error

During the time period specified, the global metadata attribute "averaging_int" is 
reported as 30 seconds when the value for this attribute should be 60 seconds.

• Time offset of tweaks from base_time(time_offset)

TWP/MPL/C2 - Reprocess: Global metadata error

During the time period specified, the global metadata attribute "averaging_int" is 
reported as 30 seconds when the value for this attribute should be 60 seconds.

• Time offset of tweaks from base_time(time_offset)

TWP/MPL/C2 - Optical throughput unacceptable

The optical throughput of the MPL at Nauru is below an acceptable level. Despite an 
extended stay to address the problem in Feb 2003, the problem was unresolved.  An additional 
repair was attempted in July 2003 with no significant success.  Several optical components 
were replaced and the system was repeatedly re-aligned.  

The system appears to have been properly collimated as the shape of the signal is 
appropriate for both near and far range.  The magnitude of the signal was simply too low.  This 
signal decrease was apparent in ambient background values as well as from atmospheric 
signal, so the impact on data quality was not as severe as might otherwise be the case.  The 
MPL was still capable of detecting high altitude cirrus (day and night) but the 
sensitivity was reduced.

• null(Raw data stream - documentation not supported)

• Attenuated backscatter(detector_counts)