SGP/RL/C1 - Frequent intermittent drop-outs in the WFOV photon counting signals

Beginning suddenly, near 1330 UTC on 31 May 2011, the liquid water and all three WFOV 
channels began showing intermittent and frequent ?drop-outs? in the photon counting signals. 
These drop-outs were periods when the signal would momentarily fade and then come back. 

This problem, which was traced to a malfunction of the Licel data recorders, occurred at 
irregular intervals and with such frequency as to render the data from the affected 
channels useless. This problem persisted until repairs were made to the Licel transient 
recorders on 19 August 2011. 

Although only the WFOV channels (and liquid water channel) were affected, the aerosol and 
water vapor mixing ratio VAPs are computed by combining NFOV and WFOV channels. Thus, all 
of these higher level data products were adversely impacted by the drop-out problem.

The NFOV data in the sgprlC1.a0 and sgprlprofmerge1turnC1.c0 datastreams were unaffected 
by the "drop-out" problem. These signals could be used to compute aerosol optical 
properties and water vapor mixing ratio.

• Maximum altitude used in the calculation of the aerosol optical depth from the
  extinction_1 profile(aod_1_max_ht)
• Uncertainty of the aerosol extinction coefficient profile calculated from the
  aerosol backscatter coefficient(extinction_from_backscatter_error)
• Error in the aerosol optical depth calculated from the extinction_married1
  profile(aod_married1_error)
• Aerosol optical depth from the surface computed from the
  extinction_from_backscatter profiles(aod_bscat_profile)
• Aerosol extinction coefficient profile calculated from backscatter and the
  extinction-to-backscatter ratio(extinction_from_backscatter)
• Maximum altitude used in the calculation of the aerosol optical depth from the
  extinction_married1 profile(aod_married1_max_ht)
• Aerosol extinction coefficient profile created by marrying the merged extinction
  from N2 data with the extinction from backscatter data(extinction_married1)
• Error in the aerosol optical depth calculated from the extinction_1 profile(aod_1_error)
• Uncertainty of the aerosol extinction coefficient profile from the low N2
  channel(extinction_low_error)
• Aerosol optical depth from the surface computed from the extinction_1 profiles(aod_1_profile)
• Error in the aerosol optical depth calculated from the
  extinction_from_backscatter profile(aod_bscat_error)
• Aerosol volume backscattering coefficient at 355 nm(backscatter)
• Vertical resolution of the low aerosol extinction coefficient profile data(extinction_low_resolution)
• Aerosol backscatter coefficient at 355 nm - smoothed to N2 extinction resolution(smoothed_backscatter)
• Ratio of aerosol extinction to aerosol backscatter(Sa_1)
• Aerosol extinction coefficient profile created by merging the two N2 channels
  extinction profiles(extinction_1)
• Maximum altitude used in the calculation of the aerosol optical depth from the
  extinction_from_backscatter profile(aod_bscat_max_ht)
• Mask indicating from where the extinction value came from in the aerosol
  extinction coefficient profile created by marrying the merged extinction from N2
  data w(extinction_married1_mask)
• Ratio of aerosol extinction to aerosol backscatter(Sa_2)
• Aerosol optical depth from the surface computed from the married1 extinction
  profiles(aod_married1_profile)
• Aerosol optical depth calculated from the extinction_1 profile(aod_1)
• Aerosol extinction coefficient profile from the low N2 channel data(extinction_low)
• Uncertainty of the married aerosol extinction coefficient profile(extinction_married1_error)
• Aerosol optical depth calculated from the extinction_from_backscatter profile(aod_bscat)
• Uncertainty in the aerosol backscatter coefficient at 355 nm(backscatter_error)
• Uncertainty in the aerosol backscatter coefficient at 355 nm - smoothed to N2
  extinction resolution(smoothed_backscatter_error)
• Uncertainty of the aerosol extinction coefficient profile created by merging the
  two N2 channels extinction profiles(extinction_1_error)
• Aerosol optical depth calculated from the extinction_married1 profile(aod_married1)

• Mean electronic background subtracted from the low channel elastic analog signal(electronic_background_elastic_analog_low)
• Glue coefficient (slope) for high liquid channel(liquid_counts_high_glue_coef_slope)
• Adjustment to ensure solar background from AD and PC data are identical for the
  low nitrogen channel(solar_offset_nudge_nl)
• Glue coefficient (offset) for high liquid channel(liquid_counts_high_glue_coef_offset)
• Fit parameters for the low nitrogen channel(parameters_nitrogen_low)
• Solar background in the low channel nitrogen channel(solar_background_nitrogen_low)
• Fit parameters for the low water vapor channel(parameters_water_low)
• Glue coefficient (offset) for low elastic channel(elastic_counts_low_glue_coef_offset)
• Glue coefficient (offset) for low nitrogen channel(nitrogen_counts_low_glue_coef_offset)
• Adjustment to ensure solar background from AD and PC data are identical for the
  low elastic channel(solar_offset_nudge_el)
• Glue coefficient (slope) for low water vapor channel(water_counts_low_glue_coef_slope)
• Glue coefficient (slope) for low elastic channel(elastic_counts_low_glue_coef_slope)
• Adjustment to ensure solar background from AD and PC data are identical for the
  low water vapor channel(solar_offset_nudge_wl)
• Number of photons counted in the low elastic (aerosol) channel(elastic_counts_low)
• Number of photons counted in the low water vapor channel(water_counts_low)
• Glue coefficient (slope) for low nitrogen channel(nitrogen_counts_low_glue_coef_slope)
• Mean electronic background subtracted from the low channel water vapor analog
  signal(electronic_background_water_analog_low)
• Glue coefficient (offset) for low water vapor channel(water_counts_low_glue_coef_offset)
• Fit parameters for the low elastic channel(parameters_elastic_low)
• Number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• Solar background in the low channel water channel(solar_background_water_low)
• Mean electronic background subtracted from the low channel nitrogen analog
  signal(electronic_background_nitrogen_analog_low)
• Number of photons counted in the liquid water channel(liquid_counts_high)
• Adjustment to ensure solar background from AD and PC data are identical for the
  high liquid channel(solar_offset_nudge_lw)
• Solar background in the low channel elastic channel(solar_background_elastic_low)

• Aerosol backscatter coefficient uncertainty(bscat_err)
• Aerosol volume backscattering coefficient at 355 nm(backscatter)
• Uncertainty of the aerosol scattering ratio profile created by merging the two
  channels(asr_1_error)
• Cloud mask(cloud_mask)
• Uncertainty of the aerosol scattering ratio profile created by merging the two
  Calibrated channels(cal_asr_1_error)
• Aerosol scattering ratio profile created by merging the two Calibrated channels(cal_asr_1)
• Scale factor added to the low aerosol scattering ratio at each time sample(scale_add_lo)
• Uncertainty of the Calibrated aerosol scattering ratio profile from the low
  channel(cal_asr_error_low)
• Corrected Aerosol volume backscattering coefficient at 355 nm - removed negative
  vals(corr_bscat)
• Aerosol scattering ratio profile from the low channel(asr_low)
• Aerosol scattering ratio profile created by merging the two channels(asr_1)
• Calibration factor applied to the low aerosol scattering ratio at each time
  sample(cal_factor_lo)
• Uncertainty of the aerosol scattering ratio profile from the low channel(asr_error_low)
• Differential transmission correction for aerosols(diff_trans_aerosol_corr)
• Calibrated Aerosol scattering ratio profile from the low channel(cal_asr_low)

• Calibration factor used to match the high channel mixing ratio to the low
  channel mixing ratio(calib_high_low)
• Random error in the precipitable water vapor observed by the Raman lidar(pwv_rl_err)
• Water vapor mixing ratio profile created by merging the two calibrated channels
  together with the surface in-situ measurements(mixing_ratio_3)
• Water vapor mixing ratio profile created by merging the two calibrated channels(mixing_ratio_2)
• Uncertainty of the water vapor mixing ratio profile created by merging the two
  calibrated channels(mixing_ratio_2_error)
• Water vapor mixing ratio profile created by merging the two channels(mixing_ratio_1)
• Water vapor mixing ratio profile from the low channel(mixing_ratio_low)
• Uncertainty of the water vapor mixing ratio profile created by merging the two
  calibrated channels(mixing_ratio_3_error)
• Uncertainty of the water vapor mixing ratio profile created by merging the two
  channels(mixing_ratio_1_error)
• Suggested maximum altitude to use the water vapor data from the Raman lidar(wv_rl_max_height)
• Fraction of the total precipitable water vapor in the column sensed by the Raman
  lidar(pwv_rl_fraction)
• Relative humidity over ice calculated from the merged water vapor mixing ratio
  data(relative_humidity_over_ice)
• Relative humidity calculated from the merged water vapor mixing ratio data(relative_humidity)
• Uncertainty of the water vapor mixing ratio profile from the low channel(mixing_ratio_error_low)
• Precipitable water vapor observed by the Raman lidar(pwv_rl)

• Number of photons counted in the low water vapor channel(water_counts_low)
• Summed analog signal in the liquid water channel(liquid_analog_high)
• Number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• Number of photons counted in the liquid water channel(liquid_counts_high)
• Summed analog signal in the low elastic channel(elastic_analog_low)
• Summed analog signal in the low nitrogen channel(nitrogen_analog_low)
• Summed analog signal in the low water vapor channel(water_analog_low)
• Number of photons counted in the low elastic (aerosol) channel(elastic_counts_low)