SGP/MPL/C1 - Signal degrading

The MPL viewport window was blown off during a storm on 2002/09/25.  The MPL received a 
soaking of rain.  Following this event, although site operations cleaned and dried the 
optics, the lidar performance continued to degrade over the next few months.  Although 
initially suitable for cloud detection, by Dec 10th the lidar was providing useful results only 
during the day (oddly enough).  By Jan 16, the detector was dead.  

It is not recommended to depend on night-time cloud base heights after Dec. 10 2002. 

It is not recommended to use any of the data after 9/25 for aerosol retrievals.

• Time offset from base_time(base_time)
• Preliminary cloud base height above ground level(preliminary_cbh)
• Maximum altitude retrieved from multichannel scalar card.(max_altitude)
• Time offset of tweaks from base_time(time_offset)
• Detector temperature(detector_temp)
• Repetition rate, or Trigger Frequency of the laser(trigger_freq)
• north latitude for all the input platforms.(lat)
• distance to center of range bin after correcting for offset in sync(range)
• Number of laser pulses summed during measurement interval(shots_summed)
• value represents date when configuration is first applicable as YYYYMMDD(property)
• Background signal(background_signal)
• Aerosol volume backscattering coefficient at 355 nm(backscatter)
• Amount of time the actual laser pulse lags behind the sync trigger(laser_sync_offset)
• Voltage level which operates the thermistor(voltage_10)
• Height of bins above ground level for the temperature, retrieved water vapor,
  and pressure profile(height)
• Time in nanoseconds for each range bin of multichannel scalar card.(range_bin_time)
• Number of laser pulses summed during measurement interval(shots_sum)
• Amount of time the scalar lags behind the sync trigger(scalar_sync_offset)
• Laser temperature(laser_temp)
• Angle of inclination with respect to horizontal(transceiver_altitude_angle)
• Distance from leading edge of first range bin to the center of each bin.(range_bins)
• effective range offset due to poor sync between laser firing and A/D trigger.(range_offset)
• Repetition rate, or Trigger Frequency of the laser(pulse_rep)
• Angle of orientation with respect to true geographic north(transceiver_azimuth_angle)
• Energy output per pulse of transmitted laser beam at 523 nm (Doubled Nd-YLF)(energy_monitor)
• Instrument temperature(instrument_temp)
• Amount of time laser pulse lags behind the scalar trigger(laser_scalar_sync_offset)
• altitude above sea levelaltunits(alt)
• Width of range-bins calculated from range_bin_time(range_bin_width)
• Time offset from midnight of date of file. For CO data, this is identical to
  time_offset and is included for compatibility.(time)
• required to correct raw counts for detector deadtime prior to all other
  corrections.(deadtime_correction)
• Voltage level which operates the energy monitor(voltage_15)
• Sum of raw backscatter counts per bin prior to ANY corrections.(total_counts)
• Filter temperature(filter_temp)
• Voltage level which operates the A/D card and the detector(voltage_05)
• east longitude for all the input platforms.(lon)

• Background signal(background_signal)
• Instrument temperature(instrument_temp)
• Time offset of tweaks from base_time(time_offset)
• Cloud base height (for first cloud above height threshold)(cloud_base_height)
• north latitude for all the input platforms.(lat)
• Energy output per pulse of transmitted laser beam at 523 nm (Doubled Nd-YLF)(energy_monitor)
• Cloud mask(cloud_mask_2)
• Height of bins above ground level for the temperature, retrieved water vapor,
  and pressure profile(height)
• Number of laser pulses summed during measurement interval(shots_summed)
• Repetition rate, or Trigger Frequency of the laser(pulse_rep)
• The update time of the historical baseline used for the cloud boundary
  determination of this sample(baseline_update_time)
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• Aerosol volume backscattering coefficient at 355 nm(backscatter)
• Flag indicating whether the beam was extinguished at indicated cloud top(cloud_top_attenuation_flag)
• Detector temperature(detector_temp)
• Laser temperature(laser_temp)
• Cloud mask(cloud_mask_1)
• east longitude for all the input platforms.(lon)
• Time offset from base_time(base_time)
• Relative random error in backscatter profiles(random_error)
• altitude above sea levelaltunits(alt)