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.

• Attenuated backscatter(detector_counts)

• null(Raw data stream - documentation not supported)

TWP/MPL/C2 - Detector on instrument failed.

The detector on the MPL failed. The result are zeros for the detector counts data.

• Attenuated backscatter(detector_counts)

• null(Raw data stream - documentation not supported)

TWP/MPL/C2 - Missing data

The MPL was turned off due to a dead detector.

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

• null(Raw data stream - documentation not supported)