| Subject: | SGP/RL/C1 - Frequent intermittent drop-outs in the WFOV photon counting signals |
| DataStreams: | sgp10rlprofasr1ferrC1.c1, sgp10rlprofext1ferrC1.c1, sgp10rlprofmr1turnC1.c1, sgprlC1.a0,
sgprlprofmerge1turnC1.c0
|
| Description: | 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. |
| Measurements: | sgp10rlprofasr1ferrC1.c1: - Corrected Aerosol volume backscatt. coeff. at 355 nm - removed negative vals(corr_bscat)
- cal_asr_low
- cal_asr_error_low
- bscat_err
- cal_asr_1_error
- Aerosol scattering ratio profile created by merging the two channels(asr_1)
- scale_add_lo
- asr_error_low
- diff_trans_aerosol_corr
- cloud_mask
- cal_factor_lo
- cal_asr_1
- Aerosol scattering ratio profile from the low channel(asr_low)
- Backscatter(backscatter)
- asr_1_error
sgprlprofmerge1turnC1.c0: - solar_background_nitrogen_low
- solar_background_water_low
- nitrogen_counts_low_glue_coef_slope
- parameters_water_low
- solar_offset_nudge_nl
- elastic_counts_low
- solar_offset_nudge_wl
- electronic_background_elastic_analog_low
- solar_offset_nudge_el
- nitrogen_counts_low_glue_coef_offset
- solar_background_elastic_low
- parameters_elastic_low
- water_counts_low_glue_coef_offset
- elastic_counts_low_glue_coef_slope
- electronic_background_nitrogen_analog_low
- water_counts_low_glue_coef_slope
- liquid_counts_high_glue_coef_slope
- solar_offset_nudge_lw
- liquid_counts_high
- electronic_background_water_analog_low
- liquid_counts_high_glue_coef_offset
- parameters_nitrogen_low
- elastic_counts_low_glue_coef_offset
- water_counts_low
- Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
sgp10rlprofmr1turnC1.c1: - wv_rl_max_height
- mixing_ratio_low
- pwv_rl_fraction
- Water vapor mixing ratio profile created by merging the two channels(mixing_ratio_1)
- Water vapor mixing ratio profile; combines 2 calibrated channels with sfc. obs.(mixing_ratio_3)
- Water vapor mixing ratio profile created by merging the two calibrated channels(mixing_ratio_2)
- relative_humidity_over_ice
- mixing_ratio_1_error
- relative_humidity
- mixing_ratio_3_error
- mixing_ratio_2_error
- mixing_ratio_error_low
- calib_high_low
- Precipitable water vapor observed by the Raman lidar(pwv_rl)
- pwv_rl_err
sgp10rlprofext1ferrC1.c1: - extinction_low_resolution
- Aerosol optical depth calculated from the extinction_1 profile(aod_1)
- extinction_married1
- smoothed_backscatter
- extinction_1
- extinction_married1_error
- Backscatter(backscatter)
- aod_married1
- aod_bscat_max_ht
- aod_bscat_error
- smoothed_backscatter_error
- extinction_married1_mask
- extinction_from_backscatter
- extinction_from_backscatter_error
- Sa_2
- aod_1_max_ht
- Sa_1
- extinction_low
- Aerosol optical depth from the surface computed from the extinction_1 profiles(aod_1_profile)
- aod_married1_error
- aod_married1_profile
- aod_married1_max_ht
- extinction_low_error
- extinction_1_error
- Aerosol optical depth calculated from the extinction_from_backscatter profile(aod_bscat)
- aod_1_error
- Optical depth, aerosol, from sfc, from extinction_from_backscatter profiles(aod_bscat_profile)
- backscatter_error
sgprlC1.a0: - water_analog_low
- water_counts_low
- Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
- Raman backscatter, summed analog signal in the low nitrogen channel(nitrogen_analog_low)
- liquid_analog_high
- elastic_analog_low
- elastic_counts_low
- liquid_counts_high
|
| Subject: | SGP/RL/C1 - Bad shot count data |
| DataStreams: | sgprlC1.a0, sgprlprofmerge1turnC1.c0, sgp10rlprofasr1ferrC1.c1, sgp10rlprofdep1turnC1.c1,
sgp10rlprofext1ferrC1.c1, sgp10rlprofmr1turnC1.c1
|
| Description: | The number of laser pulses averaged per profile, or shot count, exhibited erratic behavior
during the periods in question. The values reported in the sgprlC1.a0 datastream were
incorrect and varied radically from profile to profile. Shot counts are used in the Merge
VAP to compute photon count rates, which are then used by all the other RL VAPs. Thus, the
shot count problem renders all of the RL VAPs bad or suspect during the periods in question.
It appears that the problem was caused as the signal on the line between two triggering
units got noisier over time, causing the second unit to occasionally trigger on noise. The
second unit triggers the Licel electronics. So the false triggering on the second unit
caused false shot count readings. On 6 October 2011 the trigger level was adjusted by the
on-site technician, and this appears to have solved the problem. |
| Measurements: | sgp10rlprofasr1ferrC1.c1: - cal_asr_high
- bscat_err
- vert_scale_hi
- scale_add_hi_2
- cal_asr_error_high
- diff_trans_aerosol_corr
- cal_factor_hi
- cal_asr_1
- Aerosol scattering ratio profile from the low channel(asr_low)
- asr_1_error
- cal_asr_low
- hi_cal_type
- tweaks
- cal_asr_error_low
- cal_asr_1_error
- scale_add_lo
- shots_summed
- Corrected Aerosol volume backscatt. coeff. at 355 nm - removed negative vals(corr_bscat)
- Aerosol scattering ratio profile from the high channel(asr_high)
- Aerosol scattering ratio profile created by merging the two channels(asr_1)
- asr_error_low
- scale_add_hi
- vert_scale_hi_2
- cloud_mask
- cal_factor_lo
- asr_error_high
sgprlprofmerge1turnC1.c0: - electronic_background_t1_analog_high
- Raman backscatter, number of photons counted in the high nitrogen channel(nitrogen_counts_high)
- solar_offset_nudge_wl
- electronic_background_water_analog_high
- solar_offset_nudge_eh
- t1_counts_high_glue_coef_offset
- solar_offset_nudge_el
- nitrogen_counts_low_glue_coef_offset
- solar_offset_nudge_wh
- water_counts_low_glue_coef_offset
- elastic_counts_high_glue_coef_slope
- elastic_counts_low_glue_coef_slope
- electronic_background_nitrogen_analog_low
- parameters_water_high
- t1_counts_high
- merge_flags_low
- water_counts_high_glue_coef_offset
- merge_flags_high
- Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
- parameters_liquid_high
- t2_counts_high
- solar_offset_nudge_t2
- Preliminary cloud base height above ground level(cbh)
- parameters
- solar_offset_nudge_t1
- solar_background_water_low
- parameters_water_low
- electronic_background_elastic_analog_high
- depolarization_counts_high_glue_coef_offset
- solar_offset_nudge_dh
- liquid_counts_high_glue_coef_slope
- electronic_background_nitrogen_analog_high
- t2_counts_high_glue_coef_slope
- nitrogen_counts_high_glue_coef_offset
- electronic_background_water_analog_low
- parameters_nitrogen_low
- elastic_counts_low_glue_coef_offset
- water_counts_low
- parameters_depolarization_high
- solar_offset_nudge_nl
- t2_counts_high_glue_coef_offset
- solar_offset_nudge_nh
- electronic_background_elastic_analog_low
- elastic_counts_high
- solar_background_elastic_low
- electronic_background_liquid_analog_high
- parameters_elastic_low
- water_counts_high
- liquid_counts_high
- cloud_value_check
- elastic_counts_high_glue_coef_offset
- liquid_counts_high_glue_coef_offset
- solar_background_nitrogen_low
- electronic_background_t2_analog_high
- electronic_background_depolarization_analog_high
- shots_summed
- nitrogen_counts_low_glue_coef_slope
- water_counts_high_glue_coef_slope
- elastic_counts_low
- parameters_t1_high
- parameters_nitrogen_high
- t1_counts_high_glue_coef_slope
- depolarization_counts_high_glue_coef_slope
- parameters_elastic_high
- parameters_t2_high
- water_counts_low_glue_coef_slope
- nitrogen_counts_high_glue_coef_slope
- solar_offset_nudge_lw
- depolarization_counts_high
- n2_cloud_check_value
sgp10rlprofdep1turnC1.c1: - attenuation_flag
- calibration_factor
- cloud_mask
- tweaks
- cloud_optical_thickness_aer
- shots_summed
- Cloud base height(cloud_base_height)
- cloud_depth
- cloud top height(cloud_top_height)
- cloud_optical_thickness_n2
- Linear depolarization ratio profile(depolarization_ratio)
- depolarization_ratio_error
sgp10rlprofmr1turnC1.c1: - mixing_ratio_error_high
- mixing_ratio_error_low
- Precipitable water vapor observed by the Raman lidar(pwv_rl)
- wv_rl_max_height
- mixing_ratio_low
- pwv_rl_fraction
- Water vapor mixing ratio profile created by merging the two channels(mixing_ratio_1)
- Water vapor mixing ratio profile; combines 2 calibrated channels with sfc. obs.(mixing_ratio_3)
- Water vapor mixing ratio profile created by merging the two calibrated channels(mixing_ratio_2)
- relative_humidity_over_ice
- shots_summed
- mixing_ratio_high
- mixing_ratio_1_error
- diff_trans_aerosol_corr
- mixing_ratio_2_error
- pwv_rl_err
- tweaks
- relative_humidity
- mixing_ratio_3_error
- vertical_resolution_bright_mode
- calib_high_low
- vertical_resolution_normal_mode
- calib_factor
sgp10rlprofext1ferrC1.c1: - extinction_low_resolution
- Aerosol optical depth calculated from the extinction_1 profile(aod_1)
- smoothed_backscatter
- extinction_married1
- Backscatter(backscatter)
- aod_bscat_max_ht
- tweaks
- extinction_high_olap_corrected
- extinction_from_backscatter
- extinction_from_backscatter_error
- aod_1_max_ht
- extinction_low
- extinction_high_error
- Aerosol optical depth from the surface computed from the extinction_1 profiles(aod_1_profile)
- aod_married1_profile
- aod_married1_max_ht
- extinction_1_resolution
- extinction_married1_error
- aod_married1
- smoothed_backscatter_error
- Sa_2
- Sa_1
- extinction_high_olap_corrected_error
- Aerosol optical depth calculated from the extinction_from_backscatter profile(aod_bscat)
- aod_1_error
- extinction_1
- aod_bscat_error
- extinction_married1_mask
- extinction_high_resolution
- shots_summed
- extinction_high
- extinction_1_error
- backscatter_error
- Optical depth, aerosol, from sfc, from extinction_from_backscatter profiles(aod_bscat_profile)
- aod_married1_error
- extinction_low_error
sgprlC1.a0: - t1_counts_high
- t1_analog_high
- cloud_value_check
- water_analog_low
- shots_summed_water_low
- n2_cloud_check_value
- Raman backscatter, summed analog signal in the high nitrogen channel(nitrogen_analog_high)
- shots_summed_water_high
- t2_analog_high
- shots_summed_liquid_high
- shots_summed_elastic_low
- elastic_counts_high
- shots_summed_t1_high
- water_counts_low
- liquid_analog_high
- shots_summed
- elastic_analog_high
- water_analog_high
- shots_summed_depolarization_high
- Raman backscatter, number of photons counted in the high nitrogen channel(nitrogen_counts_high)
- shots_summed_t2_high
- Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
- Raman backscatter, summed analog signal in the low nitrogen channel(nitrogen_analog_low)
- t2_counts_high
- elastic_analog_low
- shots_summed_nitrogen_low
- depolarization_counts_high
- shots_summed_elastic_high
- water_counts_high
- depolarization_analog_high
- shots_summed_nitrogen_high
- elastic_counts_low
- liquid_counts_high
|