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.

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

• MPL Cloth et al. Algorithm Significance Mask(SigniMaskMplCloth)
• Heights
• time_offset
• base_time

• Heights
• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)
• time_offset
• base_time

NSA/MPL/C1 - Laser Q-Switch Problem

At about 22:52 UTC on 2004/01/19, the NSA MPL appears to have suffered a temporary failure 
of the laser Q-Switch.  This results in a complete loss of lidar data immediately 
thereafter.  The problem was resolved (at least for the time being) by disconnecting and 
reconnecting the Q-Switch cable on 2004/01/24 at about 00:16 UTC.  Data after this time appears 
good.

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

• Heights
• time_offset
• base_time
• MPL Cloth et al. Algorithm Significance Mask(SigniMaskMplCloth)

• range_bin_time
• background_signal
• Altitude above mean sea level(alt)
• voltage_15
• instrument_temp
• Preliminary cloud base height(preliminary_cbh)
• max_altitude
• detector_counts
• range_bins
• Pressure, associated geometric height, at altitude, NGM model output(height)
• time
• range
• voltage_05
• voltage_10
• East longitude(lon)
• pulse_rep
• filter_temp
• detector_temp
• base_time
• laser_temp
• range_bin_width
• shots_summed
• time_offset
• energy_monitor
• North latitude(lat)
• range_offset

• Heights
• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)
• time_offset
• base_time

NSA/MPL/C1 - Instrument problem

On 2/18, the energy monitor on the MPL dropped from 11 microjoules per second to 2 
microjoules per second.  This severely affected data quality.  This appears to be have been an 
intermittent cable problem for the laser Q-Switch. A new cable was provided and installed 
on 2-24.

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

• energy_monitor

NSA/MPL/C1 - Hardware Failure/Missing Data

Data are missing during this extended period due to a hardware failure.

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

• MPL Cloth et al. Algorithm Significance Mask(SigniMaskMplCloth)
• Heights
• time_offset
• base_time

• Heights
• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)
• time_offset
• base_time

NSA/C1 - Site-wide power failure

The Barrow facility experienced a site-wide power failure on 12/13.  Power was restored to 
most instruments between 2250 and 2330 GMT.

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

• range_bin_time
• background_signal
• Altitude above mean sea level(alt)
• voltage_15
• instrument_temp
• Preliminary cloud base height(preliminary_cbh)
• max_altitude
• detector_counts
• range_bins
• Pressure, associated geometric height, at altitude, NGM model output(height)
• time
• range
• voltage_05
• voltage_10
• East longitude(lon)
• pulse_rep
• filter_temp
• detector_temp
• base_time
• laser_temp
• range_bin_width
• shots_summed
• time_offset
• energy_monitor
• North latitude(lat)
• range_offset

NSA/MPL/C1 - Frost on Viewport Window

During periods of extremely cold outside temperatures (-30 C or below), the MPL may suffer 
from reduced sensitivity due to obscuration of its viewport window with frost or 
condensation.  

During the winter of 1998-1999, on-site observers noted frost or condensation obscuring 
part or all of the viewport window.  A fan providing blowing heated air on the viewport had 
failed.  Although replacement of this fan reduced the degree of obscuration, the problem 
was not entirely eliminated.  During the summer of 1999 a more robust  forced-air system 
was installed and the problem was essentially solved except for during isolated cases of 
extremely cold weather.  Under these extreme conditions partial or complete obscuration 
of the window is still possible with the result that cloud detection sensitivity will be 
reduced depending on the fraction of the window surface obscured.  Even with significant 
obscuration, the MPL may still detect clouds and the cloud base heights of detected 
clouds will be reported correctly.  This problem is one of detection sensitivity only and does 
not affect the range scale in any way.

• Preliminary cloud base height(preliminary_cbh)
• background_signal
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)

NSA/MPL/C1 - Frost on Viewport Window

During periods of extremely cold outside temperatures (-30 C or below), the MPL may suffer 
from reduced sensitivity due to obscuration of its viewport window with frost or 
condensation.  

During the winter of 1998-1999, on-site observers noted frost or condensation obscuring 
part or all of the viewport window.  A fan providing blowing heated air on the viewport had 
failed.  Although replacement of this fan reduced the degree of obscuration, the problem 
was not entirely eliminated.  During the summer of 1999 a more robust  forced-air system 
was installed and the problem was essentially solved except for during isolated cases of 
extremely cold weather.  Under these extreme conditions partial or complete obscuration 
of the window is still possible with the result that cloud detection sensitivity will be 
reduced depending on the fraction of the window surface obscured.  Even with significant 
obscuration, the MPL may still detect clouds and the cloud base heights of detected 
clouds will be reported correctly.  This problem is one of detection sensitivity only and does 
not affect the range scale in any way.

• MPL Cloth et al. Algorithm Significance Mask(SigniMaskMplCloth)
• Heights

• Heights
• MPL Cloth et al. Algorithm Cloud Mask(CloudMaskMplCloth)

NSA/MPL/C1 - Frost on Viewport Window

During periods of extremely cold outside temperatures (-30 C or below), the MPL may suffer 
from reduced sensitivity due to obscuration of its viewport window with frost or 
condensation.  

During the winter of 1998-1999, on-site observers noted frost or condensation obscuring 
part or all of the viewport window.  A fan providing blowing heated air on the viewport had 
failed.  Although replacement of this fan reduced the degree of obscuration, the problem 
was not entirely eliminated.  During the summer of 1999 a more robust  forced-air system 
was installed and the problem was essentially solved except for during isolated cases of 
extremely cold weather.  Under these extreme conditions partial or complete obscuration 
of the window is still possible with the result that cloud detection sensitivity will be 
reduced depending on the fraction of the window surface obscured.  Even with significant 
obscuration, the MPL may still detect clouds and the cloud base heights of detected 
clouds will be reported correctly.  This problem is one of detection sensitivity only and does 
not affect the range scale in any way.

• background_signal
• Preliminary cloud base height(preliminary_cbh)
• detector_counts

NSA/MPL/C1 - MPL clock drift

The MPL PC clock was noted to be off (slow) by more than an hour over a several day 
period.  It has previously been noted that the time synchronization program "D-4" fails to 
update the PC clock under certain circumstances.  As a result, the program "D-4" was replaced 
by "AboutTime" on 2/5/2004.  

The specifics of this problem are not well understood.  It turns out that the instrument 
has TWO clocks on the instrument computer display - one being displayed by the MPL 
software and the other being the PC clock displayed in the lower right-hand corner of the 
screen. The MPL software clock was the one that is noted on daily rounds and was never off by 
any amount. Apparently the only clock that was off was the computer clock.

What is clear is that between the time the MPL computer was installed on 11-11-2003 and 
the CM log on 1-06-2004 the MPL clock exhibited a discrepancy of over 1 hour and 20 
minutes.  What is not clear is whether this clock discrepancy was also applied to the data time 
stamps.  Furthermore, seven days later the MPL clock exhibited only a 1.77 second drift.  
Not exceptional at all, and not in line with the previous discrepancy of more than 4800 
seconds over a span of 57 days.

Attempts to identify gradual correctible clock drift in the MPL data were not successful.  
As a worst-case scenario, the MPL data may be inappropriately time-stamped by as much a 
1 hour 20 minutes and 41 seconds slow relative to UTC between the dates of 2003-11-11 and 
2004-01-06.  After this time until 2004-02-05 time synchronization was maintained within 
a few seconds a day with local observer assistance.

• base_time
• time_offset
• time

• time
• base_time
• time_offset

PYE/MPL/M1 - wrong temperature calibration

Wrong calibration coefficients were applied to the temperature values.  These are 
engineering housekeeping data only.  The scientifically relevant measurements were unaffected.

• laser_temp
• detector_temp
• filter_temp
• instrument_temp

NSA/MPL/C1 - Diode failure

On 3/25, the energy monitor on the MPL dropped from 11 microjoules per second to 2 
microjoules per second.  We determined the problem was the diode; it reached the end of its 
lifetime. A replacement was sent.  Data quality returned to normal.

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

• energy_monitor

NIM/MPL/M1 - False Positive Cloud Base Height Values During Solar Noon

As the laser ages, the output reduces.  This lowers the signal to noise ratio. The lower 
signal to noise ratio interferes with the cloud base height algorithm to correctly 
determine if a cloud is actually present. During solar noon the signal to noise ratio is the 
lowest. This condition results in many false positive values. The values start at a high 
altitude and progressively get lower as the sun gets to zenith. The trend reverses as the 
sun passes. The pattern in the data resembles a “V” shape starting 2 hours before solar 
noon to 2 hour past. A low incident of false positive values exists from 20051227. However, 
the condition becomes prominent on 20060303 - 20060420. The cloud base calibration table 
was modified to compensate for the lower signal to noise levels. 

Note: If a cloud is actually present, the cloud base algorithm will determine the height 
and report correctly. The false positive values are only a concern during cloud free 
conditions.

• Preliminary cloud base height(preliminary_cbh)

PYE/MPL/M1 - Erroneous temperatures

The temperature readings for the laser, detector, and instrument are erroneous.  Incorrect 
calibration factors; data should not be used.  This time period is prior to the official 
start of the PYE deployment.

• laser_temp
• detector_temp
• instrument_temp

NSA/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

PYE/MPL/M1 - 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

NIM/MPL/M1 - 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

NSA/MPL/C1 - Detector Failure

Beginning 12/25, the signal return displayed serious aliasing, reflection, or ringing of 
the detector, with a highly repetitive pattern repeating six or more times within the 
lowest 15 km.  On 01/02, the detector became very difficult to put into any type of operating 
condition. When it did operate, the "aliased" signal pattern was still present.

The detector was replaced.

• background_signal_std
• laser_temp
• energy_monitor
• signal_return
• background_signal

NSA/MPL/C1 - Missing data

System was down for detector replacement.

• base_time
• time
• laser_temp
• range_offset
• East longitude(lon)
• signal_return
• dead_time_corrected
• Pressure, associated geometric height, at altitude, NGM model output(height)
• range
• North latitude(lat)
• shots_per_avg
• scope_temp
• polarization_control_voltage
• Preliminary cloud base height(preliminary_cbh)
• Altitude above mean sea level(alt)
• max_altitude
• time_offset
• background_signal_std
• range_bin_width
• num_bins
• detector_temp
• pulse_rep
• range_bin_time
• polarization_control
• range_bins
• energy_monitor
• background_signal
• num_channels

NSA/MPL/C1 - No cross polarized data

The cross polarizor was not functioning so there is no cross polarized data.  All data 
during the specified period is circularly polarized.

• signal_return

FKB/MPL/M1 - Striping of vertical time section for signal return

Vertical stripes were showing up in the MPLPOL backscatter plots. Problem was likely 
associated with turbulence from the heating fan air blowing in front of telescope.

Data are still good for almost all uses.  In particular, cloud detection algorithms are 
unaffected.  Depolarization is seemingly unaffected.  Only in possible calculation of 
extinction will this be a possible problem.

• signal_return

NSA/MPL/C1 - Bad Cross-Polarized data

The polarizer box was not recycled when the system was rebooted; thus only circularly 
polarized light was being emitted.  Ignore all cross polarized data.

• polarization_control_voltage
• signal_return

• Attenuated backscatter, cross pol(signal_return_cross_pol)
• aqc_signal_return_cross_pol
• background_signal_std_cross_pol
• background_signal_cross_pol
• polarization_control_voltage_cross_pol
• Preliminary cloud base height above ground level, cross-pol(preliminary_cbh_cross_pol)

NSA/MPL/C1/C2 - No cross polarization data

Even though the polarization voltage was reported as switching between circular and cross 
polarization states, there was no cross polarization taking place because the 
polarization box had not been recycled following a system reboot.

You will not be able to create depolarization values.  However all other processes, such 
as cloud base determination should be ok.

• polarization_control_voltage
• signal_return

• Attenuated backscatter, cross pol(signal_return_cross_pol)
• aqc_signal_return_cross_pol
• nsamples_cross_pol_average
• background_signal_std_cross_pol
• background_signal_cross_pol
• polarization_control_voltage_cross_pol
• Preliminary cloud base height above ground level, cross-pol(preliminary_cbh_cross_pol)

HFE/MPL/M1 - Frosting/Condensation

On various days during the China deployment, condensation accumulated on the view port 
window of the MPL and compromised its capability to detect clouds.  This problem most often 
occurred during nighttime hours from May through early September.  

During the listed times, cloud retrievals and aerosol profiles should be considered 
doubtful or in error.

The dates/times of occurrence are:
16:00-23:59 GMT on 05/18
17:00-22:00 GMT on 05/23
20:00-22:00 GMT on 05/25
15:00-23:59 GMT on 06/07
17:00-23:59 GMT on 06/08
15:00-23:00 GMT on 06/09
14:00-18:00 GMT on 06/18
18:00-21:00 GMT on 06/21
14:00-16:00 GMT on 06/23
16:00-21:00 GMT on 06/27
17:00-20:00 GMT on 06/28
      22:00 GMT on 06/29
19:00-23:00 GMT on 06/30
13:30-22:30 GMT on 07/02
16:00-17:30 GMT on 07/03 
20:30-22:00 GMT on 07/03
21:30-22:30 GMT on 07/05
13:00-22:00 GMT on 07/06
17:00-18:00 GMT on 07/07
21:00-22:30 GMT on 07/07
16:00-23:59 GMT on 07/10
11:00-23:00 GMT on 07/11
18:00-23:00 GMT on 07/12
15:00-16:00 GMT on 07/13
18:00-23:59 GMT on 07/14
18:00-21:00 GMT on 07/15
17:30-23:00 GMT on 07/16
17:00-23:00 GMT on 07/17
13:00-23:30 GMT on 07/20
18:00-23:00 GMT on 07/24
21:00-23:00 GMT on 07/25
21:00-22:30 GMT on 07/27
12:00-23:59 GMT on 08/02
16:00-21:30 GMT on 08/03
16:00-23:00 GMT on 08/04
14:00-22:30 GMT on 08/05
19:00-23:00 GMT on 08/07
19:00-21:30 GMT on 08/08
15:00-23:30 GMT on 08/10
17:30-23:30 GMT on 08/12
14:00-15:00 GMT on 08/14
16:30-22:30 GMT on 08/14
21:30-22:30 GMT on 08/17
12:00-23:59 GMT on 08/18
12:00-13:30 GMT on 08/19
20:00-23:30 GMT on 08/19
15:00-23:59 GMT on 08/20
11:00-23:59 GMT on 08/22
11:00-23:30 GMT on 08/23
12:00-23:30 GMT on 08/25
13:00-23:30 GMT on 08/26
16:30-23:59 GMT on 08/27
17:00-23:00 GMT on 08/31
15:00-23:59 GMT on 09/01
15:00-20:00 GMT on 09/02
19:30-23:59 GMT on 09/05
16:30-22:30 GMT on 09/09
19:30-23:59 GMT on 09/12
20:30-23:59 GMT on 09/15
14:00-16:30 GMT on 09/16
19:00-23:59 GMT on 09/16
20:30-23:59 GMT on 10/29
22:00-23:59 GMT on 11/01
20:00-23:59 GMT on 11/23
00:00-02:00 GMT on 11/24

• background_signal_std
• Preliminary cloud base height(preliminary_cbh)
• East longitude(lon)
• range
• signal_return
• num_channels
• North latitude(lat)
• detector_temp
• polarization_control
• shots_per_avg
• polarization_control_voltage
• range_bin_width
• Altitude above mean sea level(alt)
• base_time
• num_bins
• energy_monitor
• time
• pulse_rep
• time_offset
• range_bins
• range_offset
• max_altitude
• background_signal
• range_bin_time
• Pressure, associated geometric height, at altitude, NGM model output(height)
• laser_temp
• scope_temp
• dead_time_corrected

GRW/MPL/M1 - Missing data

Data are missing and unrecoverable.

• North latitude(lat)
• shots_per_avg
• time
• range_bins
• Altitude above mean sea level(alt)
• polarization_control_voltage
• energy_monitor
• pulse_rep
• laser_temp
• num_bins
• range
• Preliminary cloud base height(preliminary_cbh)
• signal_return
• background_signal
• East longitude(lon)
• range_bin_width
• max_altitude
• polarization_control
• background_signal_std
• scope_temp
• range_bin_time
• base_time
• detector_temp
• time_offset
• dead_time_corrected
• range_offset
• num_channels
• Pressure, associated geometric height, at altitude, NGM model output(height)

GRW/MPL/M1 - Time clock Error

Domain Time II was not installed or working properly on the MPLPOL instrument at the 
initial start at GRW.  The clock was off by 5 minutes 55 seconds at the beginning of the 
period and drifted further so it was off by 6 minutes 8 seconds at the end of the time period.

• time_offset
• time
• base_time

SBS/MPL/S1 - Degradation of cross-pol component

During this period, the cross polarization component steadily degraded.  It is difficult 
to ascertain the exact date when this began to occur because the atmosphere is light on 
aerosols and has considerable ice particles which leads to apparent cross polarization when 
this may not have been the case.

During the latter half of this deployment, depolarization values are likely too large and 
should be regarded with care.  Cloud determination is likely unaffected.

• Attenuated backscatter, cross pol(signal_return_cross_pol)
• background_signal_std_cross_pol
• background_signal_cross_pol
• qc_signal_return_cross_pol

NSA/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

PVC/MPL/M1 - Instrument failure after power outage

MPL was intermittently down for a few days before going completely down for ~17 days.  
When it came back online on 10/22, the background signals were too high. The instrument was 
replaced 20130123.

• polarization_control
• pulse_rep
• Preliminary cloud base height(preliminary_cbh)
• num_channels
• mcs_mode
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• num_bins
• Attenuated backscatter, copol(signal_return_co_pol)
• background_signal_std_cross_pol
• polarization_control_voltage
• range_bins
• scope_temp
• range_bin_time
• Pressure, associated geometric height, at altitude, NGM model output(height)
• range_bin_width
• deadtime_correction
• range
• overlap_correction
• max_altitude
• deadtime_correction_counts
• background_signal_std_co_pol
• overlap_correction_heights
• background_signal_co_pol
• range_offset
• dead_time_corrected
• first_data_bin
• background_signal_cross_pol

MAG/MPL/M1 - Instrument problem causing pulse failure

False triggering of the laser causes ingest to misinterpret beginning of data.  Moreover, 
laser does not produce full pulse, so there is no reliable data.

• range
• polarization_control_voltage
• background_signal_cross_pol
• background_signal_co_pol
• overlap_correction
• dead_time_corrected
• scope_temp
• Attenuated backscatter, copol(signal_return_co_pol)
• energy_monitor
• range_bin_width
• overlap_correction_heights
• deadtime_correction
• range_bin_time
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• max_altitude
• background_signal_std_cross_pol
• pulse_rep
• laser_temp
• polarization_control
• detector_temp
• Preliminary cloud base height(preliminary_cbh)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• first_data_bin
• background_signal_std_co_pol
• deadtime_correction_counts
• range_offset
• range_bins

MAG/ALL/M1 - Ship in Dry Dock

Ship was at dry dock without MAGIC instruments or in transit to or from dry dock.  No 
instrument data available.

• qc_signal_return_cross_pol
• Altitude above mean sea level(alt)
• qc_detector_temp
• range
• polarization_control_voltage
• background_signal_cross_pol
• North latitude(lat)
• background_signal_co_pol
• qc_range_offset
• overlap_correction
• dead_time_corrected
• scope_temp
• Attenuated backscatter, copol(signal_return_co_pol)
• energy_monitor
• num_bins
• range_bin_width
• qc_time
• overlap_correction_heights
• deadtime_correction
• time
• range_bin_time
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• qc_laser_temp
• max_altitude
• background_signal_std_cross_pol
• pulse_rep
• qc_preliminary_cbh
• base_time
• laser_temp
• polarization_control
• detector_temp
• time_offset
• qc_energy_monitor
• qc_scope_temp
• East longitude(lon)
• Preliminary cloud base height(preliminary_cbh)
• qc_signal_return_co_pol
• mcs_mode
• Pressure, associated geometric height, at altitude, NGM model output(height)
• first_data_bin
• background_signal_std_co_pol
• deadtime_correction_counts
• num_channels
• range_bins
• range_offset

ENA/MPL/C1 - Reprocessing Notice (RID 1003)

See below for details of reprocessing that was completed on 20150626.  Original 
DQR category: 4 (Red, Incorrect).

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

The MPL was on standard time, not UTC, and the problem went uncorrected until 20131130.  
Data have a one hour time offset.  Data marked with timestamp 000000 should be corrected 
to reflect the actual UTC time of 010000.

• energy_monitor
• range_bin_time
• deadtime_correction_counts
• Preliminary cloud base height(preliminary_cbh)
• background_signal_std_cross_pol
• background_signal_cross_pol
• base_time
• dead_time_corrected
• range_offset
• first_data_bin
• laser_temp
• detector_temp
• time
• background_signal_std_co_pol
• background_signal_co_pol
• polarization_control_voltage
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• scope_temp
• time_offset
• range_bin_width
• polarization_control
• Attenuated backscatter, copol(signal_return_co_pol)
• deadtime_correction

MAG/MPL/M1 - Missing data

System returned to vendor for repair. Laser power supply problems.  Data are missing and 
unrecoverable.

• qc_signal_return_cross_pol
• Altitude above mean sea level(alt)
• qc_detector_temp
• range
• polarization_control_voltage
• background_signal_cross_pol
• North latitude(lat)
• background_signal_co_pol
• qc_range_offset
• overlap_correction
• dead_time_corrected
• scope_temp
• Attenuated backscatter, copol(signal_return_co_pol)
• energy_monitor
• num_bins
• range_bin_width
• qc_time
• overlap_correction_heights
• deadtime_correction
• time
• range_bin_time
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• qc_laser_temp
• max_altitude
• background_signal_std_cross_pol
• pulse_rep
• qc_preliminary_cbh
• base_time
• laser_temp
• polarization_control
• detector_temp
• time_offset
• qc_energy_monitor
• qc_scope_temp
• East longitude(lon)
• Preliminary cloud base height(preliminary_cbh)
• qc_signal_return_co_pol
• mcs_mode
• Pressure, associated geometric height, at altitude, NGM model output(height)
• first_data_bin
• background_signal_std_co_pol
• deadtime_correction_counts
• num_channels
• range_bins
• range_offset

MAG/MPL/M1 - Loss of transmit signal triggers incorrect height

Range gate information is incorrect because zero-height bin not identified due to 
insufficient transmit signal

• range
• qc_signal_return_cross_pol
• Altitude above mean sea level(alt)
• qc_signal_return_co_pol
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• first_data_bin
• range_offset
• Attenuated backscatter, copol(signal_return_co_pol)

OLI/MPL/M1 - No transmit pulse: receive only

There was no laser firing during this period. Background values only

• Attenuated backscatter, copol(signal_return_co_pol)
• Attenuated backscatter, cross pol(signal_return_cross_pol)

MAO/MPL/M1 - No transmit pulse, background only

No transmit pulse produced by instrument resulting in no backscatter returns. Only 
background values recorded.

• Attenuated backscatter, copol(signal_return_co_pol)
• Attenuated backscatter, cross pol(signal_return_cross_pol)

NSA/MPLCMASK/C1 - Reprocessing Notice (RID 1137)

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

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

Linear depolarization ratio calculation is incorrect in the VAP processing code.

• linear_depol_ratio

MAO/MPLCMASK/M1 - Reprocessing Notice (RID 1139)

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

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

Linear depolarization ratio calculation is incorrect in the VAP processing code.

• linear_depol_ratio

FKB/MPLCMASK/M1 - Reprocessing Notice (RID 1141)

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

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

Linear depolarization ratio calculation is incorrect in the VAP processing code.

• linear_depol_ratio

GAN/MPLCMASK/M1 - Reprocessing Notice (RID 1142)

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

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

Linear depolarization ratio calculation is incorrect in the VAP processing code.

• linear_depol_ratio

HFE/MPLCMASK/M1 - Reprocessing Notice (RID 1143)

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

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

Linear depolarization ratio calculation is incorrect in the VAP processing code.

• linear_depol_ratio

PVC/MPLCMASK/M1 - Reprocessing Notice (RID 1144)

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

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

Linear depolarization ratio calculation is incorrect in the VAP processing code.

• linear_depol_ratio

OLI/MPL/M1 - Laser transmit problem

Laser transmit did not occur correctly, resulting in only background values.

• Attenuated backscatter, copol(signal_return_co_pol)
• Attenuated backscatter, cross pol(signal_return_cross_pol)

OLI/MPL/M1 - Environmental

Data missing due to generator failure

• num_bins
• range_bin_time
• deadtime_correction
• base_time
• first_data_bin
• qc_energy_monitor
• overlap_correction_heights
• polarization_control
• time_offset
• East longitude(lon)
• range_bins
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• max_altitude
• background_signal_cross_pol
• time
• pulse_rep
• dead_time_corrected
• qc_scope_temp
• qc_signal_return_cross_pol
• scope_temp
• overlap_correction
• polarization_control_voltage
• deadtime_correction_counts
• Altitude above mean sea level(alt)
• background_signal_co_pol
• num_channels
• energy_monitor
• laser_temp
• qc_range_offset
• qc_preliminary_cbh
• detector_temp
• qc_detector_temp
• range_bin_width
• qc_signal_return_co_pol
• range_offset
• mcs_mode
• background_signal_std_co_pol
• North latitude(lat)
• Attenuated backscatter, copol(signal_return_co_pol)
• range
• Pressure, associated geometric height, at altitude, NGM model output(height)
• background_signal_std_cross_pol
• qc_laser_temp
• qc_time
• Preliminary cloud base height(preliminary_cbh)

MAG/AOS/ALL/M1/S1/S2 - Ship in port

The ship was in port during these periods and the measurements may be affected by various 
sources (overhead cranes, anthropogenic sources, etc).

Note: Dates and times were found by looking at the NAV datastream.  The standard deviation 
of pitch, roll, and surge velocity were used to determine when the ship was slowing down 
to enter port or speeding up to leave port.  Thresholds used; pitch (0.01), roll (0.01), 
surge velocity (3.0)

• Altitude above mean sea level(alt)
• qc_detector_temp
• qc_signal_return_cross_pol
• range
• polarization_control_voltage
• background_signal_cross_pol
• North latitude(lat)
• background_signal_co_pol
• qc_range_offset
• overlap_correction
• dead_time_corrected
• scope_temp
• Attenuated backscatter, copol(signal_return_co_pol)
• energy_monitor
• range_bin_width
• qc_time
• num_bins
• overlap_correction_heights
• time
• deadtime_correction
• range_bin_time
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• qc_laser_temp
• max_altitude
• background_signal_std_cross_pol
• pulse_rep
• qc_preliminary_cbh
• base_time
• laser_temp
• polarization_control
• detector_temp
• time_offset
• qc_energy_monitor
• East longitude(lon)
• qc_scope_temp
• Preliminary cloud base height(preliminary_cbh)
• qc_signal_return_co_pol
• mcs_mode
• first_data_bin
• background_signal_std_co_pol
• Pressure, associated geometric height, at altitude, NGM model output(height)
• num_channels
• deadtime_correction_counts
• range_bins
• range_offset

MAO/MPL/M1 - Reprocessing Notice (RID 1313)

See below for details of reprocessing that was completed on 20160107.
Original DQR category: 0 (Black, Missing).

-----------------------------------------------------------
preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

OLI/MPL/M1 - Reprocessing Notice (RID 1314)

See below for details of reprocessing that was completed on 20160107.
Original DQR category: 0 (Black, Missing).

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

preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

PGH/MPL/M1 - Reprocessing Notice (RID 1315)

See below for details of reprocessing that was completed on 20151207.
Original DQR category: 0 (Black, Missing).

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

preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

PVC/MPL/M1 - Reprocessing Notice (RID 1316)

See below for details of reprocessing that was completed on 20151207.
Original DQR category: 0 (Black, Missing).

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

preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

TMP/MPL/M1 - Reprocessing Notice (RID 1317)

See below for details of reprocessing that was completed on 20151207.
Original DQR category: 0 (Black, Missing).

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

preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

NSA/MPL/C1  - Reprocessing Notice (RID 1305)

See below for details of reprocessing that was completed on 20160107.
Original DQR category: 0 (Black, Missing).

-----------------------------------------------------------
preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

SBS/MPL/S1 - Reprocessing Notice (RID 1308)

See below for details of reprocessing that was completed on 20151207.
Original DQR category: 0 (Black, Missing).

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

preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

ENA/MPL/C1 - Reprocessing Notice (RID 1309)

See below for details of reprocessing that was completed on 20160107.
Original DQR category: 0 (Black, Missing).

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

preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

GAN/MPL/M1 - Reprocessing Notice (RID 1311)

See below for details of reprocessing that was completed on 20151207.
Original DQR category: 0 (Black, Missing).

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

preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

MAG/MPL/M1 - Reprocessing Notice (RID 1312)

See below for details of reprocessing that was completed on 20151207.
Original DQR category: 0 (Black, Missing).

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

preliminary_cbh data are were never derived and are set to -9999.

• Preliminary cloud base height(preliminary_cbh)

OLI/MPL/M1 - Data not available

No data available from any instruments during this time period.

• num_bins
• range_bin_time
• deadtime_correction
• base_time
• first_data_bin
• qc_energy_monitor
• overlap_correction_heights
• polarization_control
• time_offset
• East longitude(lon)
• range_bins
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• max_altitude
• background_signal_cross_pol
• time
• pulse_rep
• dead_time_corrected
• qc_scope_temp
• qc_signal_return_cross_pol
• scope_temp
• overlap_correction
• polarization_control_voltage
• deadtime_correction_counts
• Altitude above mean sea level(alt)
• background_signal_co_pol
• num_channels
• energy_monitor
• laser_temp
• qc_range_offset
• detector_temp
• qc_preliminary_cbh
• qc_detector_temp
• range_bin_width
• qc_signal_return_co_pol
• range_offset
• mcs_mode
• background_signal_std_co_pol
• North latitude(lat)
• Attenuated backscatter, copol(signal_return_co_pol)
• range
• Pressure, associated geometric height, at altitude, NGM model output(height)
• background_signal_std_cross_pol
• qc_laser_temp
• qc_time
• Preliminary cloud base height(preliminary_cbh)

OLI/MPL/M1 - Data not available

There is no data during this time period

• num_bins
• range_bin_time
• deadtime_correction
• base_time
• first_data_bin
• qc_energy_monitor
• overlap_correction_heights
• polarization_control
• time_offset
• East longitude(lon)
• range_bins
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• max_altitude
• background_signal_cross_pol
• time
• pulse_rep
• dead_time_corrected
• qc_scope_temp
• qc_signal_return_cross_pol
• scope_temp
• overlap_correction
• polarization_control_voltage
• deadtime_correction_counts
• Altitude above mean sea level(alt)
• background_signal_co_pol
• num_channels
• energy_monitor
• laser_temp
• qc_range_offset
• detector_temp
• qc_preliminary_cbh
• qc_detector_temp
• range_bin_width
• qc_signal_return_co_pol
• range_offset
• mcs_mode
• background_signal_std_co_pol
• North latitude(lat)
• Attenuated backscatter, copol(signal_return_co_pol)
• range
• Pressure, associated geometric height, at altitude, NGM model output(height)
• background_signal_std_cross_pol
• qc_laser_temp
• qc_time
• Preliminary cloud base height(preliminary_cbh)

OLI/MPL/M1 - Data unavailable

No data available

• num_bins
• range_bin_time
• deadtime_correction
• base_time
• first_data_bin
• qc_energy_monitor
• overlap_correction_heights
• polarization_control
• time_offset
• East longitude(lon)
• range_bins
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• max_altitude
• background_signal_cross_pol
• time
• pulse_rep
• dead_time_corrected
• qc_scope_temp
• qc_signal_return_cross_pol
• scope_temp
• overlap_correction
• polarization_control_voltage
• deadtime_correction_counts
• Altitude above mean sea level(alt)
• background_signal_co_pol
• num_channels
• energy_monitor
• laser_temp
• qc_range_offset
• detector_temp
• qc_preliminary_cbh
• qc_detector_temp
• range_bin_width
• qc_signal_return_co_pol
• range_offset
• mcs_mode
• background_signal_std_co_pol
• North latitude(lat)
• Attenuated backscatter, copol(signal_return_co_pol)
• range
• Pressure, associated geometric height, at altitude, NGM model output(height)
• background_signal_std_cross_pol
• qc_laser_temp
• qc_time
• Preliminary cloud base height(preliminary_cbh)

OLI/MPL/M1 - Broken heater fan

MPL data is not noticeably affected by the failure of the heater fan. For the time period 
of the DQR, a comparison with ceilometer signal returns shows similar cloud base heights.

• num_bins
• deadtime_correction
• range_bin_time
• first_data_bin
• overlap_correction_heights
• polarization_control
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• max_altitude
• range_bins
• background_signal_cross_pol
• pulse_rep
• dead_time_corrected
• scope_temp
• overlap_correction
• polarization_control_voltage
• deadtime_correction_counts
• num_channels
• background_signal_co_pol
• laser_fire_bin
• energy_monitor
• laser_temp
• detector_temp
• range_bin_width
• shots_per_avg
• range_offset
• mcs_mode
• background_signal_std_co_pol
• Attenuated backscatter, copol(signal_return_co_pol)
• range
• background_signal_std_cross_pol
• Pressure, associated geometric height, at altitude, NGM model output(height)
• Preliminary cloud base height(preliminary_cbh)

ENA/C1 - Reprocess: Slightly incorrect location fields

Some of the instruments are being processed with the previous "GRW-Azores" lat/lon/alt 
instead of the new "ENA-Azores" lat/lon/alt. The differences are minor, but will be 
corrected. The respective GRW and ENA lat, lon, and alt values are as follows:
 
GRW  lat = 39.0911 ;
ENA lat = 39.0916 ;
GRW  lon = -28.0297 ;
ENA  lon = -28.0257 ;
GRW  alt = 26 ;
ENA  alt = 30.48 ;

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

ASI/MPL/M1 - instrument

Later than planned deployment of the instrument.

• scope_temp
• Preliminary cloud base height(preliminary_cbh)
• East longitude(lon)
• qc_scope_temp
• Pressure, associated geometric height, at altitude, NGM model output(height)
• num_bins
• range_bins
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• qc_preliminary_cbh
• polarization_control_voltage
• Altitude above mean sea level(alt)
• background_signal_cross_pol
• Attenuated backscatter, copol(signal_return_co_pol)
• range_bin_time
• num_channels
• energy_monitor
• North latitude(lat)
• qc_laser_temp
• range_bin_width
• laser_temp
• background_signal_co_pol
• qc_detector_temp
• range_offset
• polarization_control
• deadtime_correction
• time
• shots_per_avg
• background_signal_std_co_pol
• qc_time
• overlap_correction_heights
• dead_time_corrected
• deadtime_correction_counts
• qc_energy_monitor
• max_altitude
• laser_fire_bin
• background_signal_std_cross_pol
• overlap_correction
• detector_temp
• qc_signal_return_co_pol
• range
• pulse_rep
• qc_signal_return_cross_pol
• base_time
• mcs_mode
• first_data_bin
• time_offset
• qc_range_offset

OLI/MPL/M1 - Instrument communication failure

Data missing. Data collected during the period from 13:00 UTC 07/20/16 to 16:00 UTC 
07/22/16 is just noise as instrument communication failed during this time.

• num_bins
• deadtime_correction
• range_bin_time
• first_data_bin
• overlap_correction_heights
• polarization_control
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• max_altitude
• range_bins
• background_signal_cross_pol
• pulse_rep
• dead_time_corrected
• scope_temp
• overlap_correction
• polarization_control_voltage
• deadtime_correction_counts
• num_channels
• background_signal_co_pol
• laser_fire_bin
• energy_monitor
• laser_temp
• detector_temp
• range_bin_width
• shots_per_avg
• range_offset
• mcs_mode
• background_signal_std_co_pol
• Attenuated backscatter, copol(signal_return_co_pol)
• range
• background_signal_std_cross_pol
• Pressure, associated geometric height, at altitude, NGM model output(height)
• Preliminary cloud base height(preliminary_cbh)

ASI/MPL/M1 - Reprocess: New overlap correction

Vendor has recently provided an overlap correction which needs to replace the overlap 
currently being included in the data files. This does not affect MPL data quality.

• overlap_correction
• overlap_correction_heights

AWR/MPLCMASK/M1 - Reprocess: Software Error

The MPLCMASK VAP was expecting the MPL to be covered around local solar noon. As a result, 
the algorithm intermittently set much of the data to -9999 during this time period after 
the site transitioned to total darkness during the winter months. During the peak of 
this problem, the impacted fields were set to -9999 from approximately 0:00-2:19 UTC each day.

This information is being provided in a transparent DQR due to the intermittent nature of 
the problem and the fact that the impacted data are already set to -9999 and flagged by 
the automated quality control variables in the VAP. 

A future reprocessing task will correct this problem.

• Lowest cloud base height above ground level (AGL)(cloud_base)
• backscatter_snr
• linear_depol_snr
• cloud_top_attenuation_flag
• Satellite-measured cloud top(cloud_top)
• cloud_top_layer
• cloud_base_layer
• num_cloud_layers
• linear_depol_ratio
• Backscatter, ceilometer, range and sensitivity corrected(backscatter)
• shots_summed
• Cloud mask(cloud_mask)

ASI/MPL/M1 - Instrument averaging time increased to 30 seconds

To understand what was causing frequent spikes in the MPL energy levels, the averaging 
time was increased to 30s during this period. The averaging time was reverted back to the 
original 10s averaging time at the end of the DQR period.

• scope_temp
• Preliminary cloud base height(preliminary_cbh)
• Pressure, associated geometric height, at altitude, NGM model output(height)
• range_bins
• num_bins
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• polarization_control_voltage
• background_signal_cross_pol
• Attenuated backscatter, copol(signal_return_co_pol)
• range_bin_time
• num_channels
• energy_monitor
• range_bin_width
• laser_temp
• background_signal_co_pol
• range_offset
• polarization_control
• deadtime_correction
• shots_per_avg
• background_signal_std_co_pol
• overlap_correction_heights
• dead_time_corrected
• deadtime_correction_counts
• max_altitude
• laser_fire_bin
• overlap_correction
• background_signal_std_cross_pol
• detector_temp
• range
• pulse_rep
• mcs_mode
• first_data_bin