NSA/MPL/C1 - laser head failure

On 2002-04-28 the laser energy was observed to decrease throughout the day.  Although low 
clouds continued to be detected, by the end of the day the output laser energy was about 
10% of nomimal.  This decrease continued throughout 2002-04-29 to the extent that clouds 
were no longer detected.  The source of failure was eventually determined to be the laser 
head, requiring the MPL to be shipped for repair.  The MPL was reinstalled on 2002-08-28 
at about 01:00 UTC.  

MPL NSA data from 2002-04-29 through 2002-08-27 (inclusive) should not be used.

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• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)
• Range Heights (center of radar sample volume)(Heights)
• base time in epoch(base_time)
• Time offset from base_time(time_offset)

• base time in epoch(base_time)
• Time offset from base_time(time_offset)
• Range Heights (center of radar sample volume)(Heights)
• MPL Cloth et al. Algorithm Significance Mask(SigniMaskMplCloth)

• Filter Temperature(filter_temp)
• base time in epoch(base_time)
• Repetition Rate, or Trigger Frequency of the laser(pulse_rep)
• Amount of time the actual laser pulse lags behind the sync trigger(laser_sync_offset)
• Distance to the center of the corresponding range bin(range)
• Instrument Temperature(instrument_temp)
• Voltage level which operates the thermistor(voltage_10)
• Number of laser pulses summed during measurement interval(shots_sum)
• Sum of raw backscatter counts per bin prior to ANY corrections.(total_counts)
• Laser output energy per pulse(energy_monitor)
• Voltage level which operates the energy monitor(voltage_15)
• Angle of orientation with respect to true geographic north(transceiver_azimuth_angle)
• Aerosol volume backscattering coefficient at 355 nm(backscatter)
• Maximum altitude retrieved from multichannel scalar card.(max_altitude)
• Subtract from range_bins to yield range(range_offset)
• time_in_seconds_since_volume_start(time)
• Time in nanoseconds for each range bin of multichannel scalar card.(range_bin_time)
• lon(lon)
• Deadtime correction factor(deadtime_correction)
• Width of range-bins calculated from range_bin_time(range_bin_width)
• Time offset from base_time(time_offset)
• Distance from leading edge of first range bin to the center of each bin .(range_bins)
• Preliminary cloud base height above ground level(preliminary_cbh)
• Amount of time the scalar lags behind the sync trigger(scalar_sync_offset)
• North Latitude(lat)
• value represents earliest applicable date as yyyymmdd(property)
• Voltage level which operates the A/D card and the detector(voltage_05)
• Number of lidar pulses summed(shots_summed)
• Amount of time laser pulse lags behind the scalar trigger(laser_scalar_sync_offset)
• Angle of inclination with respect to horizontal(transceiver_altitude_angle)
• Background signal(background_signal)
• Height(height)
• Laser Temperature(laser_temp)
• Repetition rate, or Trigger Frequency of the laser(trigger_freq)
• Detector Temperature(detector_temp)
• -180.0 - +180.0(alt)

• (Raw data stream - documentation not supported)