Reprocess:SGP BLC reprocessing status

The BLC data was the subject of a reprocessing 
effort last summer in support of the ARSCL
effort.  As a result three distinct windows of
data with varying levels of processing have been
created.

1) 940401-961031 - not reprocessed.  This data
   has a 110m offset in the reported cloud base
   height (see P980831.1).  No sgpblcprofC1.a1
   data available.  Reprocessing required.

2) 961101-990630 - reprocessed.  The 110m offset
   was corrected in this data and the blcprof
   data were created.  This data still contains
   the defunct field 'operational_state' which
   was determined to be useless and was removed
   in later data.  This data will be reprocessed
   at a later date to remove the operational_state
   field to create a continuity with the current
   data.

3) 990701-present - reprocessed/processed without
   'operational_state' field.  Offset has been
   corrected or no longer exists.  The format of
   this data is the target for the previous two
   data windows.

• Cloud, base height, second lowest base detected(cloud2)
• Cloud, base height, lowest cloud detected(cloud1)
• Cloud, base height, third cloud detected by Klett algorithm(kcloud3)
• Cloud, base height, second lowest base detected by Klett algorithm(kcloud2)
• operational_state
• Cloud, base height, lowest cloud detected by Klett algorithm(kcloud1)
• Cloud, base height, third base detected with thrreshold algorithm(cloud3)

• operational_state
• Cloud, base height, third base detected with thrreshold algorithm(cloud3)
• Cloud, base height, second lowest base detected(cloud2)
• Cloud, base height, lowest cloud detected(cloud1)
• Cloud, base height, lowest cloud detected by Klett algorithm(kcloud1)
• Cloud, base height, second lowest base detected by Klett algorithm(kcloud2)
• Cloud, base height, third cloud detected by Klett algorithm(kcloud3)

SGP/BLC - Retraction of D000111.4 BLC offset

D000111.4 reported on the reprocessing status of the SGP BLC
data and indicated which time periods had been reprocessed to
remove a 110m offset.

First error:  the offset was actually 122m, not 110m.
Second error: an error in the reprocessing algorithm
              resulted in the offset not being removed.

This DQR retracts D000111.4.  All BLC data processed to date
still have a 122m offset.  That is the cloud base height 
reported in the data stream is 122m too high.

Data processed after 20000204 with version 7.0 of the algorithm 
(recorded in the header of the data file) do not contain the 
offset.

The data processed through 20000204 will be reprocessed
when resources are available.

• Cloud, base height, second lowest base detected(cloud2)
• Cloud, base height, lowest cloud detected(cloud1)
• Cloud, base height, third cloud detected by Klett algorithm(kcloud3)
• Cloud, base height, second lowest base detected by Klett algorithm(kcloud2)
• Cloud, base height, lowest cloud detected by Klett algorithm(kcloud1)
• Cloud, base height, third base detected with thrreshold algorithm(cloud3)

• Cloud, base height, third cloud detected by Klett algorithm(kcloud3)
• Cloud, base height, third base detected with thrreshold algorithm(cloud3)
• Cloud, base height, second lowest base detected(cloud2)
• Cloud, base height, lowest cloud detected(cloud1)
• Cloud, base height, lowest cloud detected by Klett algorithm(kcloud1)
• Cloud, base height, second lowest base detected by Klett algorithm(kcloud2)

SGP/MPL/C1 - Data missing due to hardware failures

The MPL instrument was out of service during the time
range specified due to hardware failures. Data during
this period are missing and unrecoverable.

• Preliminary cloud base height above ground level(cbh)
• East longitude(lon)
• Altitude above mean sea level(alt)
• base_time
• time_offset
• North latitude(lat)

• East longitude(lon)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• range_offset
• laser_scalar_sync_offset
• Preliminary cloud base height(preliminary_cbh)
• filter_temp
• trigger_freq
• time
• energy_monitor
• transceiver_altitude_angle
• voltage_15
• voltage_10
• pulse_rep
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• laser_sync_offset
• range_bin_time
• laser_temp
• time_offset
• base_time
• scalar_sync_offset
• instrument_temp
• background_signal
• total_counts
• North latitude(lat)
• shots_sum
• range
• voltage_05
• max_altitude
• range_bins
• detector_temp
• shots_summed
• deadtime_correction
• Altitude above mean sea level(alt)
• property
• range_bin_width
• transceiver_azimuth_angle

• background_signal
• energy_monitor
• Altitude above mean sea level(alt)
• Cloud base height(cloud_base_height)
• cloud_top_attenuation_flag
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• East longitude(lon)
• detector_temp
• baseline_update_time
• random_error
• cloud_mask_2
• cloud_mask_1
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• pulse_rep
• time_offset
• shots_summed
• North latitude(lat)
• instrument_temp
• base_time
• Pressure, associated geometric height, at altitude, NGM model output(height)
• laser_temp

SGP/ARSCL/C1 - ARSCL Cloud Bases and Low-level reflectivities

Prior to February 4, 2000, the ARSCL data set incorporated data from the
Beaufort Laser Ceilometer as one of its inputs.  Because of the BLC's
high spatial resolution, this data was often chosen by ARSCL as the
"CloudBaseBestEstimate" for boundary layer clouds. It was subsequently
determined that the BLC cloud base was biased, with the BLC reporting
cloud base heights that are 122 meters too high.

The bias error will be corrected when the entire ARSCL data set is
reprocessed as part of release_4.  (The release version number is included
the the netCDF global comments).   This reprocessing will also include a
small correction the the MMCR near-field reflectivities.  This correction
is less than 1 dB except for hydrometers within 200 meters of the surface.

Thanks to Roger Marchand for helping bracket this problem.

• CloudBase, Best estimate(CloudBaseBestEstimate)

• Reflectivity(Reflectivity)
• BLC/VCEIL Clothiaux et al. Algorithm Cloud Base Height(CloudBaseCeilometerCloth)
• MMCR Reflectivity, Best estimate, Hydrometer(ReflectivityBestEstimate)
• BLC/VCEIL Standard Algorithm Cloud Base Height(CloudBaseCeilometerStd)
• CloudBase, Best estimate(CloudBaseBestEstimate)

• BLC/VCEIL Clothiaux et al. Algorithm Cloud Base Height(CloudBaseCeilometerCloth)
• BLC/VCEIL Standard Algorithm Cloud Base Height(CloudBaseCeilometerStd)

SGP/RL/C1 - Alternatively processed data available

Reprocessed ARM Raman Lidar water vapor data is available for 
               the IHOP IOP period 20020515 to 20020625 at 
               http://iop.archive.arm.gov/arm-iop/2002/sgp/ihop/turner-raman/
               The data were reprocessed by Dave Turner to apply an improved 
               near-field correction ("overlap correction") to the water
               vapor data collected by the Raman lidar during IHOP.  These
               files contain only the water vapor data; users who require the
               aerosol and cloud fields from this instrument will need to
               retrieve the regular ARM data sets.

• t
• mixing_ratio_resolution
• pwv_rl_fraction
• Median vertical velocity(w)
• w_err
• Humidity, relative, on hybrid-b grid, derived from RUC model(rh)
• w_max_height
• Pressure, atmospheric, at altitude, ECMWF model-derived(p)
• rl_w_60m_err
• pwv_rl_err
• rl_w_60m
• Precipitable water vapor observed by the Raman lidar(pwv_rl)

• pwv_rl_fraction
• pwv_rl_err
• rl_w_60m
• w_err
• Precipitable water vapor observed by the Raman lidar(pwv_rl)
• w_max_height
• rl_w_60m_err
• Pressure, atmospheric, at altitude, ECMWF model-derived(p)
• Humidity, relative, on hybrid-b grid, derived from RUC model(rh)
• t
• mixing_ratio_resolution
• Median vertical velocity(w)

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.

• East longitude(lon)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• range_offset
• laser_scalar_sync_offset
• Preliminary cloud base height(preliminary_cbh)
• filter_temp
• trigger_freq
• time
• energy_monitor
• transceiver_altitude_angle
• voltage_15
• voltage_10
• pulse_rep
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• laser_sync_offset
• range_bin_time
• laser_temp
• time_offset
• base_time
• scalar_sync_offset
• instrument_temp
• background_signal
• total_counts
• North latitude(lat)
• shots_sum
• range
• voltage_05
• max_altitude
• range_bins
• detector_temp
• shots_summed
• deadtime_correction
• Altitude above mean sea level(alt)
• property
• range_bin_width
• transceiver_azimuth_angle

• background_signal
• energy_monitor
• Altitude above mean sea level(alt)
• Cloud base height(cloud_base_height)
• cloud_top_attenuation_flag
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• East longitude(lon)
• detector_temp
• baseline_update_time
• random_error
• cloud_mask_2
• cloud_mask_1
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• pulse_rep
• time_offset
• shots_summed
• North latitude(lat)
• instrument_temp
• base_time
• Pressure, associated geometric height, at altitude, NGM model output(height)
• laser_temp

SGP/MPL/C1 - Detector Failure

The detector failed following a period of data quality degradation.  The MPL was replaced 
on 1/31/2003.

• East longitude(lon)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• range_offset
• laser_scalar_sync_offset
• Preliminary cloud base height(preliminary_cbh)
• filter_temp
• trigger_freq
• time
• energy_monitor
• transceiver_altitude_angle
• voltage_15
• voltage_10
• pulse_rep
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• laser_sync_offset
• range_bin_time
• laser_temp
• time_offset
• base_time
• scalar_sync_offset
• instrument_temp
• background_signal
• total_counts
• North latitude(lat)
• shots_sum
• range
• voltage_05
• max_altitude
• range_bins
• detector_temp
• shots_summed
• deadtime_correction
• Altitude above mean sea level(alt)
• property
• range_bin_width
• transceiver_azimuth_angle

• background_signal
• energy_monitor
• Altitude above mean sea level(alt)
• Cloud base height(cloud_base_height)
• cloud_top_attenuation_flag
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• East longitude(lon)
• detector_temp
• baseline_update_time
• random_error
• cloud_mask_2
• cloud_mask_1
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• pulse_rep
• time_offset
• shots_summed
• North latitude(lat)
• instrument_temp
• base_time
• Pressure, associated geometric height, at altitude, NGM model output(height)
• laser_temp

SGP/RL/C1 - Metadata errors

The latitude, longitude and altitude of the Raman Lidar were
incorrectly entered into the ARM database.  The correct location
of the SGP.C1 Raman Lidar is:
      Lat: 36.609N
      Lon: 97.487W
      Alt:    311m

• East longitude(lon)
• Altitude above mean sea level(alt)
• North latitude(lat)

• Altitude above mean sea level(alt)
• East longitude(lon)
• North latitude(lat)

SGP/BLC/C1 - Metadata errors

The latitude, longitude and altitude of the Belfort Laser Ceilometer
were incorrectly entered into the ARM database.  The correct 
location of the SGP.C1 BLC was:
     Lat: 36.606N
     Lon: 97.485W
     Alt:    316m

• Altitude above mean sea level(alt)
• East longitude(lon)
• North latitude(lat)

SGP/BLC/C1 - Metadata errors

The latitude, longitude and altitude of the Belfort Laser Ceilometer
were incorrectly entered into the ARM database.  The correct 
location of the SGP.C1 BLC was:
   Lat: 36.606N
   Lon: 97.485W
   Alt:	   316m

• Altitude above mean sea level(alt)
• North latitude(lat)
• East longitude(lon)

SGP/MPL/C1 - Metadata errors

The latitude, longitude and altitude of the Micropulse Lidar
(MPL) were incorrectly entered into the ARM database.  The 
correct location of the SGP.C1 MPL is:
   Lat: 36.606N
   Lon: 97.485W
   Alt:    316m

• North latitude(lat)
• Altitude above mean sea level(alt)
• East longitude(lon)

• East longitude(lon)
• Altitude above mean sea level(alt)
• North latitude(lat)

SGP/MPL/C1 - Metadata errors

The latitude, longitude and altitude of the Micropulse Lidar
(MPL) were incorrectly entered into the ARM database.  The 
correct location of the SGP.C1 MPL is:
   Lat: 36.606N
   Lon: 97.485W
   Alt:    316m

• North latitude(lat)
• East longitude(lon)
• Altitude above mean sea level(alt)

SGP/MPL/C1 - Reduced detection sensitivity

During the time periods indicated, the laser power supply was low.  This resulted in 
compromised detection sensitivity, particularly for thin clouds and/or during daylight hours.  
That is, some clouds may not have been identified.  The low laser power would not have 
resulted in false positives.

• Preliminary cloud base height(preliminary_cbh)

• Cloud base height(cloud_base_height)
• cloud_mask_2
• cloud_mask_1
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• cloud_top_attenuation_flag

SGP/RL/C1 - Decreased sensitivity

The sensitivity of the Raman Lidar degraded significantly beginning in late 2001.  Between 
May and September 2004, the electronics were upgraded and the telescope was refurbished 
resulting in sensitivity better than when the instrument system was first installed.

A detailed technical report describing the effects of the signal degradation and the steps 
taken to correct the problem is being written.  In the interim, contact Dave Turner 
(dave.turner@pnl.gov) for more information.

• attenuation_flag
• calibration_factor
• Cloud mask(cloud_mask)
• tweaks
• East longitude(lon)
• cloud_depth
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• base_time
• time_offset
• cloud_optical_thickness_aer
• shots_summed
• cloud_optical_thickness_n2
• average_energy
• Altitude above mean sea level(alt)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• Linear depolarization ratio profile(depolarization_ratio)
• Cloud base height(cloud_base_height)
• North latitude(lat)
• depolarization_ratio_error

• Humidity, relative, on hybrid-b grid, derived from RUC model(rh)
• cmask
• Altitude above mean sea level(alt)
• aod_max_height
• rl_w_60m
• t
• pwv_rl_fraction
• East longitude(lon)
• Median vertical velocity(w)
• w_err
• base_time
• Cloud liquid water vapor by the microwave radiometer(liq_mwr)
• Pressure, atmospheric, at altitude, ECMWF model-derived(p)
• Aerosol optical depth profiles at 355 nm(aod_profile)
• shots_summed
• Preliminary cloud base height above ground level(cbh)
• sample_times_other
• Linear depolarization ratio profile(depol)
• Aerosol backscatter coefficient at 355 nm(bscat)
• w_max_height
• twr_w_60m
• rl_w_60m_err
• Precipitable water vapor observed by the Raman lidar(pwv_rl)
• Aerosol optical depth at 355 nm(aod)
• mode
• time_offset
• depol_err
• scattering_ratio_resolution
• Precipitable water vapor observed by the microwave radiometer(pwv_mwr)
• tweaks
• pwv_rl_err
• depolarization_resolution
• bscat_err
• asr_err
• Pressure, associated geometric height, at altitude, NGM model output(height)
• mixing_ratio_resolution
• North latitude(lat)
• extinction_resolution
• ext_err
• average_energy
• aod_err
• Aerosol extinction coefficient(ext)
• Aerosol scattering ratio(asr)

• Linear depolarization ratio profile(depol)
• time_offset
• rl_w_60m
• mixing_ratio_resolution
• mode
• bscat_err
• Aerosol scattering ratio(asr)
• w_max_height
• aod_max_height
• pwv_rl_fraction
• East longitude(lon)
• depol_err
• depolarization_resolution
• cmask
• base_time
• Aerosol optical depth profiles at 355 nm(aod_profile)
• sample_times_other
• w_err
• twr_w_60m
• Aerosol optical depth at 355 nm(aod)
• Pressure, atmospheric, at altitude, ECMWF model-derived(p)
• rl_w_60m_err
• Precipitable water vapor observed by the microwave radiometer(pwv_mwr)
• t
• Median vertical velocity(w)
• pwv_rl_err
• Cloud liquid water vapor by the microwave radiometer(liq_mwr)
• Precipitable water vapor observed by the Raman lidar(pwv_rl)
• Aerosol extinction coefficient(ext)
• average_energy
• aod_err
• Humidity, relative, on hybrid-b grid, derived from RUC model(rh)
• ext_err
• extinction_resolution
• scattering_ratio_resolution
• Pressure, associated geometric height, at altitude, NGM model output(height)
• North latitude(lat)
• shots_summed
• Preliminary cloud base height above ground level(cbh)
• tweaks
• asr_err
• Aerosol backscatter coefficient at 355 nm(bscat)
• Altitude above mean sea level(alt)

SGP/MMCR/C1 - Power supply failure

A power supply failed in the MMCR's receiver.  During the period of this DQR, the radar 
would appear to work but the calibration is probably incoorect during good portions of this 
time.  The power supply was replaced and normal operation resumed at 2115 on 02/11/2005.

• CloudBase, Best estimate(CloudBaseBestEstimate)
• CloudLayerBottomHeightMplCamp
• CloudLayerBottomHeightMplCloth
• time_offset
• CloudLayerTopHeightMplCloth
• CloudLayerTopHeightMplCamp
• base_time

• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)
• MMCR Reflectivity, clutter removed(ReflectivityNoClutter)
• time_offset
• MMCR Reflectivity, Best estimate, Hydrometer(ReflectivityBestEstimate)
• SignaltoNoiseRatio
• MPL Clothiaux et al. Algorithm Cloud Base Height(CloudBaseMplCloth)
• Heights
• CloudBase, Best estimate(CloudBaseBestEstimate)
• CloudLayerTopHeightMplCloth
• CloudLayerBottomHeightMplCamp
• base_time
• CloudBasePrecipitation
• ModeId
• MPL Scott Algorithm Cloud Base Height(CloudBaseMplScott)
• BLC/VCEIL Standard Algorithm Cloud Base Height(CloudBaseCeilometerStd)
• MMCR Mean Doppler Velocity(MeanDopplerVelocity)
• MPL Campbell et al. Algorithm Cloud Base Height(CloudBaseMplCamp)
• MMCR Spectral Width(SpectralWidth)
• CloudLayerBottomHeightMplCloth
• CloudLayerTopHeightMplCamp
• Reflectivity(Reflectivity)
• BLC/VCEIL Clothiaux et al. Algorithm Cloud Base Height(CloudBaseCeilometerCloth)
• RadarFirstTop
• Cloud Mask Occurrence, MPL Campbell et al. algorithm(CloudMaskMplCamp)

SGP/MPL/C1 - Sensor Calibration

The Energy Monitor records the value of the laser energy. During the time in question, the 
laser energy exceed the maximum value in the calibration table for the energy monitor. 
In other words, the value is pegged. This condition does not affect the backscatter 
signal. But it will prevent users from normalizing the backscatter signal to the laser output.

• energy_monitor

SGP/MPL/C1 - Instrument offline

Instrument was taken offline due to a failure of the laser power supply.  Data are missing 
and unrecoverable.

• East longitude(lon)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• range_offset
• laser_scalar_sync_offset
• Preliminary cloud base height(preliminary_cbh)
• filter_temp
• trigger_freq
• time
• energy_monitor
• transceiver_altitude_angle
• voltage_15
• voltage_10
• pulse_rep
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• laser_sync_offset
• range_bin_time
• laser_temp
• time_offset
• base_time
• scalar_sync_offset
• instrument_temp
• background_signal
• total_counts
• North latitude(lat)
• shots_sum
• range
• voltage_05
• max_altitude
• range_bins
• detector_temp
• shots_summed
• deadtime_correction
• Altitude above mean sea level(alt)
• property
• range_bin_width
• transceiver_azimuth_angle

• background_signal
• energy_monitor
• Altitude above mean sea level(alt)
• Cloud base height(cloud_base_height)
• cloud_top_attenuation_flag
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• East longitude(lon)
• detector_temp
• baseline_update_time
• random_error
• cloud_mask_2
• cloud_mask_1
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• pulse_rep
• time_offset
• shots_summed
• North latitude(lat)
• instrument_temp
• base_time
• Pressure, associated geometric height, at altitude, NGM model output(height)
• laser_temp

SGP/MPL/C1 - Intermittent Double Pulse from MPL laser

When Spectra Physics discontinued support for their laser diode power supply, an 
alternative was needed to extend the usefulness of the Spectra Physics laser head inside the MPLs. 
 The solution was to use a Coherent laser diode. Unfortunately, the Coherent diode 
lasers do not have the exact same characteristics as the Spectra Physics diode lasers. As a 
result, the output of the Spectra Physics laser head sometimes produces a second pulse 
close in time but lower in intensity from the first main pulse. This is known as “double pulsing”.

Not all of the Spectra Physics/Coherent combination systems produce a double pulse and the 
systems that do produce a double pulse do not always exhibit this behavior. It can be 
identified by a second peak at ~.2km. At first glance the signal in the data will resemble 
a low aerosol or cloud layer. When the double pulse is weak, the atmospheric signal will 
obscure the double pulse signal. At the ARM sites with a sunshade such as TWP and AMF, 
the double pulse can be seen when the sunshade closes during solar noon. When the sunshade 
closes, the MPL does not see atmospheric signal so the second pulse is evident. At SGP, a 
daily window cleaning is part of the routine. During this time the double pulse can be 
seen. Without a sunshade or window cleaning it is impossible to say definitively if double 
pulse is present. 

The first system to produce a double pulse was MPL s/n 008 located at TWP – C2 Nauru in 
February 2005. The second system was MPL s/n 004 located at SGP in August 2005. The 
potential for the other systems to produce a double pulse is high. However, as of March 2006, 
the MPLs at NSA, TWP – C1, TWP – C3 and AMF have not recorded data with the double pulse 
artifact. 

The ARM program is in the process of replacing all the MPLs with a newer model. After the 
new MPLs are deployed the double pulse problem should not be an issue. The old systems 
will be relegated as spares. The double pulse problem will return if an old system is 
needed to replace a failed new system.

• detector_counts

SGP/MPL/C1 - Scope temperature incorrect

The scope_temp started to jump around on 6/29 at about 19:00 GMT between 24-32C.  Then 
~03:00 GMT on 6/30 the temperature exceeded the MAX flag value of 40C and was fluctuating 
between 150-225C.  

Temp probe connection was found to be loose and was reseated 20070806.

Ignore scope temp data and assume values are valid.

• scope_temp

• scope_temp

• scope_temp

SGP/RL/C1 - Degraded sensitivity in WFOV channels

The sensitivity of all the wide field-of-view (WFOV) channels was abnormally low due a 
malfunction of the filter wheel. The filter wheel for the WFOV channels did not rotate into 
position properly and thus partially obscured the return light.

• parameters_elastic_low
• solar_background_nitrogen_low
• water_counts_low_glue_coef_offset
• elastic_counts_low_glue_coef_slope
• solar_background_water_low
• nitrogen_counts_low_glue_coef_slope
• parameters_nitrogen_low
• water_counts_low_glue_coef_slope
• parameters_water_low
• nitrogen_counts_low_glue_coef_offset
• elastic_counts_low_glue_coef_offset
• water_counts_low
• Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• solar_background_elastic_low
• elastic_counts_low

SGP/RL/C1 - No liquid water data in RLPROFmerge

From 20060906 to 20080304 the liquid water channel (LWC) was disabled due to the removal 
of its photomultiplier tube (PMT).  During this period the signals recorded in the 
sgprlC1.a0 files for the LWC contain invalid data, and so the decision was made not have the 
rlprof_merge vap process the LWC data. As a result, the sgprlprofmerge1turnC1.c0.*.cdf files 
contain NO LWC fields (variables or attributes) during this period.
   
Do not attempt to read any fields (variables or attributes) associated with the liquid 
water channel in the sgprlprofmerge1turnC1.c0.*.cdf files between the dates of 20060906 
through 20080304.

• solar_offset_nudge_lw
• liquid_counts_high
• liquid_counts_high_glue_coef_offset
• parameters_liquid_high
• liquid_counts_high_glue_coef_slope

SGP/RL/C1 - Invalid mode 0 data

On 20081112 the filter wheel for the wide field-of-view (WFOV) channel was incorrectly 
rotated. The net effect was that we were recording neutral density filter data when we 
should have been collecting data with the channels completely blocked (mode 0 data). As a 
result, the WFOV mode 0 data contains contributions from the pulse return and the solar 
background that should not be present. The mode 0 data is used in the rlprof_merge VAP to 
remove the electronic background level from the analog signal. After the problem was 
identified the filter wheel was set back to its proper rotation on 20090112.
A work-around has been implemented in the rlprof_merge VAP to handle the lack of valid 
mode 0 during the affected period. The work-around involves computing the electronic 
background from pre-pulse data during nighttime periods only. With this technique we are not 
able to estimate the range-dependence of the electronic backgound, as we did before. 
However, this range dependence is typically quite weak, and so the impact on the rlprof_merge 
output is expected to be minimal.

• electronic_background_water_analog_low
• elastic_counts_low_glue_coef_slope
• electronic_background_nitrogen_analog_low
• electronic_background_elastic_analog_low
• nitrogen_counts_low_glue_coef_slope
• water_counts_low_glue_coef_slope
• nitrogen_counts_low_glue_coef_offset
• elastic_counts_low_glue_coef_offset
• water_counts_low_glue_coef_offset
• Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• water_counts_low
• elastic_counts_low

SGP/ARSCL/C1 - Ceilometer not used during processing

The ceilometer was not used during processing due to a ceilometer data format change that 
ARSCL did not handle properly.  As a result, cloud boundaries in the lowest several 
kilometers may be less accurate than usual, as they are based solely on the micropulse lidar 
and millimeter cloud radar.

• CloudBase, Best estimate(CloudBaseBestEstimate)

• BLC/VCEIL Clothiaux et al. Algorithm Cloud Base Height(CloudBaseCeilometerCloth)
• BLC/VCEIL Standard Algorithm Cloud Base Height(CloudBaseCeilometerStd)
• CloudBase, Best estimate(CloudBaseBestEstimate)

• BLC/VCEIL Clothiaux et al. Algorithm Cloud Base Height(CloudBaseCeilometerCloth)
• BLC/VCEIL Standard Algorithm Cloud Base Height(CloudBaseCeilometerStd)

SGP/RL/C1 - Incorrect time array

On March 27 2011 at 0100 GMT the Raman lidar's instrument computer automatically advanced 
it's time by one hour (transition to daylight savings time). The problem was eventually 
fixed on March 29 2011 at 1300 when the clock was set back one hour to the correct time. 
The ingest experienced problems when the clock was set back one hour.

The time arrays in the following files are set one hour ahead of what they should be:

1. sgprlC1.a0.20110327.000001.cdf for profile indices equal to or greater than 355
2. all of sgprlC1.a0.20110327.120001.cdf
3. all of sgprlC1.a0.20110328.134549.cdf
4. all of sgprlC1.a0.20110329.000005.cdf
5. sgprlC1.a0.20110329.120005.cdf for profile indices less than or equal to 72 

Also, the time arrays in sgprlC1.a0.20110329.120005.cdf between profile indices 73 through 
641 are incorrect. In this case, the offset varies approximately linearly with profile 
index from 1 hour at index 73 to 0 at index 641. The ingest apparently introduced some 
unphysical variations in time in this part of the file.

• time_offset

• time
• time_offset
• base_time

• time_offset
• base_time

• base_time

SGP/RL/C1 - Malfunction in WFOV data acquisition

A malfunction in the data acquisition hardware resulted in corrupted data in the 
wide-field-of-view (WFOV) nitrogen, water vapor and elastic channels. The problem is so serious as 
to yield these signals useless during the period covered by this DQR.

Do not use any data products derived from the WFOV raw signals during the period covered 
by this DQR. This includes water vapor mixing ratio, aerosol scattering ratio, and aerosol 
extinction. 

The narrow-field-of-view (NFOV)channels are unaffected by this problem. So data products 
derived from only the NFOV channel should be okay. These include the 'high' channel 
signals from the merge VAP, depolarization and temperature.

• parameters_elastic_low
• water_counts_low_glue_coef_offset
• elastic_counts_low_glue_coef_slope
• nitrogen_counts_low_glue_coef_slope
• water_counts_low_glue_coef_slope
• parameters_water_low
• elastic_counts_low
• parameters_nitrogen_low
• nitrogen_counts_low_glue_coef_offset
• elastic_counts_low_glue_coef_offset
• Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• water_counts_low

• pwv_rl_fraction
• Aerosol optical depth profiles at 355 nm(aod_profile)
• rl_w_60m
• w_err
• Aerosol optical depth at 355 nm(aod)
• rl_w_60m_err
• Preliminary cloud base height above ground level(cbh)
• Median vertical velocity(w)
• pwv_rl_err
• Precipitable water vapor observed by the Raman lidar(pwv_rl)
• asr_err
• bscat_err
• Aerosol scattering ratio(asr)
• Aerosol extinction coefficient(ext)
• w_max_height
• aod_err
• cmask
• aod_max_height
• Humidity, relative, on hybrid-b grid, derived from RUC model(rh)
• ext_err
• Aerosol backscatter coefficient at 355 nm(bscat)

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.

• parameters_elastic_low
• solar_background_nitrogen_low
• water_counts_low_glue_coef_offset
• elastic_counts_low_glue_coef_slope
• electronic_background_nitrogen_analog_low
• solar_background_water_low
• nitrogen_counts_low_glue_coef_slope
• water_counts_low_glue_coef_slope
• parameters_water_low
• solar_offset_nudge_nl
• elastic_counts_low
• liquid_counts_high_glue_coef_slope
• solar_offset_nudge_lw
• liquid_counts_high
• solar_offset_nudge_wl
• electronic_background_elastic_analog_low
• electronic_background_water_analog_low
• liquid_counts_high_glue_coef_offset
• solar_offset_nudge_el
• parameters_nitrogen_low
• elastic_counts_low_glue_coef_offset
• nitrogen_counts_low_glue_coef_offset
• Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• water_counts_low
• solar_background_elastic_low

SGP/RL/C1 - Bad shot count data

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 solved the problem.


On 3 May 2012 the DG535 pulse generator, which is used to trigger the Licel data 
recorders, was swapped out with a spare. After installation of the spare, the system started 
recording erroneous values of shot counts. The problem was fixed on 12 June 2012 when the 
on-site tech increased trigger level on the DG535.

• attenuation_flag
• calibration_factor
• shots_summed
• Cloud mask(cloud_mask)
• cloud_optical_thickness_n2
• tweaks
• Linear depolarization ratio profile(depolarization_ratio)
• cloud_depth
• Cloud base height(cloud_base_height)
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• cloud_optical_thickness_aer
• depolarization_ratio_error

• solar_offset_nudge_t2
• electronic_background_t1_analog_high
• Preliminary cloud base height above ground level(cbh)
• parameters
• solar_background_nitrogen_low
• solar_offset_nudge_t1
• electronic_background_t2_analog_high
• Raman backscatter, number of photons counted in the high nitrogen channel(nitrogen_counts_high)
• electronic_background_depolarization_analog_high
• shots_summed
• nitrogen_counts_low_glue_coef_slope
• solar_background_water_low
• parameters_water_low
• solar_offset_nudge_nl
• water_counts_high_glue_coef_slope
• t2_counts_high_glue_coef_offset
• elastic_counts_low
• solar_offset_nudge_nh
• solar_offset_nudge_wl
• electronic_background_elastic_analog_low
• parameters_t1_high
• parameters_nitrogen_high
• electronic_background_water_analog_high
• solar_offset_nudge_eh
• t1_counts_high_glue_coef_offset
• t1_counts_high_glue_coef_slope
• solar_offset_nudge_el
• solar_offset_nudge_wh
• nitrogen_counts_low_glue_coef_offset
• solar_background_elastic_low
• elastic_counts_high
• electronic_background_elastic_analog_high
• depolarization_counts_high_glue_coef_slope
• electronic_background_liquid_analog_high
• parameters_elastic_low
• parameters_elastic_high
• parameters_t2_high
• water_counts_low_glue_coef_offset
• elastic_counts_high_glue_coef_slope
• elastic_counts_low_glue_coef_slope
• electronic_background_nitrogen_analog_low
• water_counts_high
• water_counts_low_glue_coef_slope
• depolarization_counts_high_glue_coef_offset
• solar_offset_nudge_dh
• nitrogen_counts_high_glue_coef_slope
• liquid_counts_high_glue_coef_slope
• solar_offset_nudge_lw
• electronic_background_nitrogen_analog_high
• parameters_water_high
• t1_counts_high
• liquid_counts_high
• t2_counts_high_glue_coef_slope
• cloud_value_check
• depolarization_counts_high
• elastic_counts_high_glue_coef_offset
• nitrogen_counts_high_glue_coef_offset
• electronic_background_water_analog_low
• n2_cloud_check_value
• merge_flags_low
• liquid_counts_high_glue_coef_offset
• water_counts_high_glue_coef_offset
• parameters_nitrogen_low
• elastic_counts_low_glue_coef_offset
• merge_flags_high
• parameters_depolarization_high
• water_counts_low
• parameters_liquid_high
• Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• t2_counts_high

SGP/MPLCMASK/C1 - Cloud layer metadata misleading

The comment in the header for cloud_base_layer indicates that a value of -1 indicates that 
no cloud is detected.  For the specified time range, a value of 0 indicates that no 
cloud is detected.

Values greater than zero indicate cloudy conditions, otherwise it is clear.

• cloud_base_layer

SGP/RL/C1 - Reprocessing Notice (RID 1026)

See below for details of reprocessing that was completed on 20140822.  Original DQR 
category:3 (Yellow, Suspect ).

-----------------------------------------------------------

Regions where photon counting rates exceed 20 MHz are 37.5 meters too high. Correct data 
by shifting down 37.5 meters.


Additional information:
The detection system in the RL uses Licel data recorders. These recorders provide 
simultaneous measurements of analog voltage and photon counts from the photo multiplier tubes. 
The analog signal has an inherent delay relative to the photon counting signal, which is 
corrected for in the rlprofmerge VAP. The delay parameter is determined through offline 
analysis by the instrument mentor, and then inputted into a configuration file that is used 
by the VAP.
During the effected period, the delay parameter for the narrow-field-of-view elastic 
channel was incorrect. As a result, the  analog signal leads the photon counting signal by 5 
range bins (5X7.5m = 37.5m). Photon counting rates that are outputted by the rlprofmerge 
VAP use the analog signals in regions where the photon counting rates exceed 20 MHz. So 
the counting rate data in these regions are (incorrectly) shifted downward by 37.5 m (i.e. 
-37.5m).

• height_high
• elastic_counts_high_glue_coef_slope
• elastic_counts_high_glue_coef_offset
• elastic_counts_high
• electronic_background_elastic_analog_high

SGP/RLPROF/C1 - Reduced signal due to partially closed laser shutter

The laser shutter was partially closed during the period in question. This resulted in a 
reduction in the sensitivity of all detection channels.

• electronic_background_t1_analog_high
• Humidity, relative, on hybrid-b grid, derived from RUC model(rh)
• Raman backscatter, number of photons counted in the high nitrogen channel(nitrogen_counts_high)
• solar_offset_nudge_nl
• height_low
• t2_counts_high_glue_coef_offset
• solar_offset_nudge_nh
• s7
• s8
• s9
• solar_offset_nudge_wl
• electronic_background_elastic_analog_low
• s1
• s2
• s3
• s4
• s5
• s6
• solar_offset_nudge_eh
• t1_counts_high_glue_coef_offset
• electronic_background_water_analog_high
• solar_offset_nudge_el
• solar_offset_nudge_wh
• nitrogen_counts_low_glue_coef_offset
• elastic_counts_high
• solar_background_elastic_low
• filter
• electronic_background_liquid_analog_high
• parameters_elastic_low
• pulse_energy
• water_counts_low_glue_coef_offset
• elastic_counts_high_glue_coef_slope
• elastic_counts_low_glue_coef_slope
• electronic_background_nitrogen_analog_low
• height_high
• water_counts_high
• t1_counts_high
• parameters_water_high
• liquid_counts_high
• cloud_value_check
• elastic_counts_high_glue_coef_offset
• temp1
• temp3
• merge_flags_low
• Model derived 2-meter temperature(temp2)
• liquid_counts_high_glue_coef_offset
• temp5
• temp4
• water_counts_high_glue_coef_offset
• temp6
• 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_background_nitrogen_low
• solar_offset_nudge_t1
• electronic_background_t2_analog_high
• shots_summed
• electronic_background_depolarization_analog_high
• solar_background_water_low
• nitrogen_counts_low_glue_coef_slope
• parameters_water_low
• s10
• water_counts_high_glue_coef_slope
• elastic_counts_low
• parameters_t1_high
• parameters_nitrogen_high
• t1_counts_high_glue_coef_slope
• electronic_background_elastic_analog_high
• depolarization_counts_high_glue_coef_slope
• parameters_elastic_high
• parameters_t2_high
• water_counts_low_glue_coef_slope
• depolarization_counts_high_glue_coef_offset
• solar_offset_nudge_dh
• nitrogen_counts_high_glue_coef_slope
• liquid_counts_high_glue_coef_slope
• solar_offset_nudge_lw
• electronic_background_nitrogen_analog_high
• t2_counts_high_glue_coef_slope
• depolarization_counts_high
• nitrogen_counts_high_glue_coef_offset
• electronic_background_water_analog_low
• n2_cloud_check_value
• parameters_nitrogen_low
• elastic_counts_low_glue_coef_offset
• water_counts_low
• parameters_depolarization_high
• laser_head

• attenuation_flag
• calibration_factor
• Cloud mask(cloud_mask)
• tweaks
• cloud_depth
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• cloud_optical_thickness_aer
• shots_summed
• cloud_optical_thickness_n2
• average_energy
• Linear depolarization ratio profile(depolarization_ratio)
• Cloud base height(cloud_base_height)
• depolarization_ratio_error

• Humidity, relative, on hybrid-b grid, derived from RUC model(rh)
• cmask
• aod_max_height
• rl_w_60m
• t
• pwv_rl_fraction
• Median vertical velocity(w)
• w_err
• Cloud liquid water vapor by the microwave radiometer(liq_mwr)
• Pressure, atmospheric, at altitude, ECMWF model-derived(p)
• Aerosol optical depth profiles at 355 nm(aod_profile)
• shots_summed
• Preliminary cloud base height above ground level(cbh)
• sample_times_other
• Linear depolarization ratio profile(depol)
• Aerosol backscatter coefficient at 355 nm(bscat)
• w_max_height
• twr_w_60m
• rl_w_60m_err
• Precipitable water vapor observed by the Raman lidar(pwv_rl)
• Aerosol optical depth at 355 nm(aod)
• mode
• depol_err
• scattering_ratio_resolution
• Precipitable water vapor observed by the microwave radiometer(pwv_mwr)
• tweaks
• pwv_rl_err
• depolarization_resolution
• bscat_err
• asr_err
• mixing_ratio_resolution
• extinction_resolution
• ext_err
• average_energy
• aod_err
• Aerosol extinction coefficient(ext)
• Aerosol scattering ratio(asr)

• Linear depolarization ratio profile(depol)
• rl_w_60m
• mixing_ratio_resolution
• mode
• bscat_err
• Aerosol scattering ratio(asr)
• w_max_height
• aod_max_height
• pwv_rl_fraction
• depol_err
• depolarization_resolution
• cmask
• Aerosol optical depth profiles at 355 nm(aod_profile)
• sample_times_other
• w_err
• twr_w_60m
• Aerosol optical depth at 355 nm(aod)
• rl_w_60m_err
• Pressure, atmospheric, at altitude, ECMWF model-derived(p)
• Precipitable water vapor observed by the microwave radiometer(pwv_mwr)
• t
• Median vertical velocity(w)
• pwv_rl_err
• Cloud liquid water vapor by the microwave radiometer(liq_mwr)
• Precipitable water vapor observed by the Raman lidar(pwv_rl)
• Aerosol extinction coefficient(ext)
• average_energy
• aod_err
• Humidity, relative, on hybrid-b grid, derived from RUC model(rh)
• ext_err
• extinction_resolution
• scattering_ratio_resolution
• shots_summed
• Preliminary cloud base height above ground level(cbh)
• tweaks
• asr_err
• Aerosol backscatter coefficient at 355 nm(bscat)

SGP/RLPROF/C1 - Reduced SNR due to partial laser blockage

The laser output was partially blocked. This resulted in reduced SNR in all detection 
channels.

• Linear depolarization ratio profile(depolarization_ratio)
• cloud_optical_thickness_n2
• cloud_optical_thickness_aer
• depolarization_ratio_error

• t1_counts_high
• liquid_counts_high
• depolarization_counts_high
• Raman backscatter, number of photons counted in the high nitrogen channel(nitrogen_counts_high)
• water_counts_high
• water_counts_low
• Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• elastic_counts_high
• t2_counts_high
• elastic_counts_low

SGP/MPLCMASK/C1 - Reprocessing Notice (RID 1136)

See below for details of reprocessing that was completed on 20140807.  Original DQR 
category: 4 (Red, Incorrect).

-----------------------------------------------------------

Linear depolarization ratio calculation incorrect in the VAP processing code.

• linear_depol_ratio

SGP/RLPROF/C1 - Invalid data due to hatch closure

The outgoing beam was completely blocked by the hatch. As a result, the data contain no 
valid atmospheric signals.

• solar_offset_nudge_t2
• electronic_background_t1_analog_high
• Preliminary cloud base height above ground level(cbh)
• solar_background_nitrogen_low
• solar_offset_nudge_t1
• electronic_background_t2_analog_high
• Raman backscatter, number of photons counted in the high nitrogen channel(nitrogen_counts_high)
• electronic_background_depolarization_analog_high
• nitrogen_counts_low_glue_coef_slope
• solar_background_water_low
• solar_offset_nudge_nl
• water_counts_high_glue_coef_slope
• t2_counts_high_glue_coef_offset
• elastic_counts_low
• solar_offset_nudge_nh
• solar_offset_nudge_wl
• electronic_background_elastic_analog_low
• t1_counts_high_glue_coef_offset
• solar_offset_nudge_eh
• electronic_background_water_analog_high
• t1_counts_high_glue_coef_slope
• solar_offset_nudge_el
• solar_offset_nudge_wh
• nitrogen_counts_low_glue_coef_offset
• solar_background_elastic_low
• elastic_counts_high
• electronic_background_elastic_analog_high
• depolarization_counts_high_glue_coef_slope
• electronic_background_liquid_analog_high
• water_counts_low_glue_coef_offset
• elastic_counts_high_glue_coef_slope
• elastic_counts_low_glue_coef_slope
• electronic_background_nitrogen_analog_low
• water_counts_high
• water_counts_low_glue_coef_slope
• depolarization_counts_high_glue_coef_offset
• solar_offset_nudge_dh
• nitrogen_counts_high_glue_coef_slope
• liquid_counts_high_glue_coef_slope
• electronic_background_nitrogen_analog_high
• solar_offset_nudge_lw
• t1_counts_high
• liquid_counts_high
• t2_counts_high_glue_coef_slope
• cloud_value_check
• depolarization_counts_high
• elastic_counts_high_glue_coef_offset
• nitrogen_counts_high_glue_coef_offset
• electronic_background_water_analog_low
• merge_flags_low
• n2_cloud_check_value
• liquid_counts_high_glue_coef_offset
• water_counts_high_glue_coef_offset
• elastic_counts_low_glue_coef_offset
• merge_flags_high
• water_counts_low
• Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• t2_counts_high

SGP - Data System Upgrades: Data Missing

The data system was undergoing upgrades.  Data were lost during this period.

• qc_second_cbh
• Altitude above mean sea level(alt)
• alt_highest_signal
• North latitude(lat)
• time_offset
• Cloud, base height, second lowest base sensed(second_cbh)
• qc_background_light
• measurement_parameters
• qc_first_cbh
• tilt_angle
• range_bounds
• base_time
• status_flag
• qc_window_contamination
• sum_backscatter
• detection_status
• range
• qc_laser_pulse_energy
• vertical_visibility
• background_light
• qc_third_cbh
• East longitude(lon)
• time_bounds
• qc_sum_backscatter
• qc_alt_highest_signal
• laser_temperature
• qc_receiver_sensitivity
• laser_pulse_energy
• Cloud, base height, lowest base sensed(first_cbh)
• qc_tilt_angle
• qc_laser_temperature
• Third cloud base height(third_cbh)
• time
• window_contamination
• qc_window_transmission
• status_string
• qc_vertical_visibility
• window_transmission
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• receiver_sensitivity

Continuing signal degradation

Despite recent efforts (970310-970314) by the instrument mentor, signal 
degradation of the MPL has continued.  The degradation has continued to the 
point that the effective range of the MPL is nearing 10 km.  The instrument mentor and PI 
have 
concluded that an overhaul of the instrument by the vendor is in order.

• Preliminary cloud base height above ground level(cbh)
• base_time
• time_offset
• East longitude(lon)
• North latitude(lat)
• Altitude above mean sea level(alt)

• North latitude(lat)
• East longitude(lon)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• range
• range_offset
• shots_sum
• laser_scalar_sync_offset
• Preliminary cloud base height(preliminary_cbh)
• filter_temp
• voltage_05
• trigger_freq
• time
• max_altitude
• range_bins
• energy_monitor
• detector_temp
• transceiver_altitude_angle
• shots_summed
• deadtime_correction
• voltage_15
• Altitude above mean sea level(alt)
• property
• voltage_10
• range_bin_width
• pulse_rep
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• laser_sync_offset
• range_bin_time
• laser_temp
• time_offset
• base_time
• scalar_sync_offset
• instrument_temp
• total_counts
• background_signal
• transceiver_azimuth_angle

Instrument misalignment report

A low-resolution (300 m) MPL system (unit number 04) was installed at the
SGP site in April '97 upon the laser diode failure of the 02 unit in
March.  Calibration of this instrument in August found that the optics
were misaligned causing a near range focusing error in the data.  
Calibration files produced for this data, while acceptable, do not 
completely correct for the problem.  As a result, aerosol property 
retrievals using this data are not suggested.  Cloud boundary heights, 
though appear satisfactory.  This system was removed from SGP in early 
September

• Backscatter, ceilometer, range and sensitivity corrected(backscatter)

Laser Output Energy Monitor at Zero

Energy monitor reading for laser output is at zero for intermittant
one-minute averaged shots during this flagged data period.  From the
lidar equation progressing to normalized relative backscatter the
laser energy is required and is a denominator.  Therefore a value of
zero will render the product as infinite.  Shots where this has taken
place are left as zeros.  It is suggested that the time period
19970425 2123 - 19970428 1459
be avoided for any quantitative analysis.

• Backscatter, ceilometer, range and sensitivity corrected(backscatter)

Laser Output Energy Monitor at Zero

Energy monitor reading for laser output is at zero for intermittant
one-minute averaged shots during this flagged data period.  From the
lidar equation progressing to normalized relative backscatter the
laser energy is required and is a denominator.  Therefore a value of
zero will render the product as infinite.  Shots where this has taken
place are left as zeros.  It is suggested that the time periods 
19970902 2211 - 19970903 1359,
19970907 1445 - 19970908 1544,
and
19970910 2142 - 19970910 2355
be avoided for any quantitative analysis.

• Backscatter, ceilometer, range and sensitivity corrected(backscatter)

SGP/MPL - Missing data due to blown detector

Sometime early 11/11 the detector on the
MPL-004 blew out.  The Detector was replaced by Albert Mendoza.
The instrument was operational on Jan. 23, 1999.

Link this to P981119.2 that reported the blown detector and the
corrective action taken

• Preliminary cloud base height above ground level(cbh)
• East longitude(lon)
• Altitude above mean sea level(alt)
• base_time
• time_offset
• North latitude(lat)

• East longitude(lon)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• range_offset
• laser_scalar_sync_offset
• Preliminary cloud base height(preliminary_cbh)
• filter_temp
• trigger_freq
• time
• energy_monitor
• transceiver_altitude_angle
• voltage_15
• voltage_10
• pulse_rep
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• laser_sync_offset
• range_bin_time
• laser_temp
• time_offset
• base_time
• scalar_sync_offset
• instrument_temp
• background_signal
• total_counts
• North latitude(lat)
• shots_sum
• range
• voltage_05
• max_altitude
• range_bins
• detector_temp
• shots_summed
• deadtime_correction
• Altitude above mean sea level(alt)
• property
• range_bin_width
• transceiver_azimuth_angle

• background_signal
• energy_monitor
• Altitude above mean sea level(alt)
• Cloud base height(cloud_base_height)
• cloud_top_attenuation_flag
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• East longitude(lon)
• detector_temp
• baseline_update_time
• random_error
• cloud_mask_2
• cloud_mask_1
• Cloud top height (for highest cloud sensed)(cloud_top_height)
• pulse_rep
• time_offset
• shots_summed
• North latitude(lat)
• instrument_temp
• base_time
• Pressure, associated geometric height, at altitude, NGM model output(height)
• laser_temp