Data Quality Reports for Session: 125989 User: c_long Completed: 02/09/2010


TABLE OF CONTENTS

DQR IDSubjectData Streams Affected
D051209.5TWP/VCEIL/C2 - occasional communication faulttwpvceil25kC2.b1
D060517.3TWP/VCEIL/C2 - Vceil computer disconnectedtwpvceil25kC2.b1
D060717.5TWP/VCEIL/C2 - Time offsettwpvceil25kC2.b1
D070201.2TWP/VCEIL/C2 - optical cross-talk compensationtwpvceil25kC2.b1
D070329.1TWP/VCEIL/C2 - Receiver failuretwpvceil25kC2.b1


DQRID : D051209.5
Start DateStart TimeEnd DateEnd Time
08/30/2005200012/12/20050346
Subject:
TWP/VCEIL/C2 - occasional communication fault
DataStreams:twpvceil25kC2.b1
Description:
Beginning August 30, 2005, the Nauru Ceilometer periodically went into a strange 
operational mode where the backscatter data exhibits vertical stripes.  Looking at the backscatter 
data - there are high amplitude oscillations occuring in the backscatter as a function 
of time at a given height.  The phenomenon appears to be more common at night.  Dates 
include: 30 Aug, 31 Aug, 1 Sep, 9 Sep, 15 Sep, 20 Oct, 22 Oct, 8 Dec, and others.

The fiber optic link to the ceilometer was faulty and causing periodic data corruption. 
The problem was corrected when the fiber optic line was replaced with a hard wired RS232 
link.
Measurements:twpvceil25kC2.b1:
  • Aerosol backscatter coefficient at 355 nm(backscatter)
  • Flag indicating aeri retrieval status(status_flag)
  • Percentage of nominal factory setting (0 to 999%)(laser_pulse_energy)
  • Third cloud base height(third_cbh)
  • Time offset of tweaks from base_time(time_offset)
  • base time(base_time)
  • Lowest cloud base height detected.(first_cbh)
  • Warning and alarm status bits(status_string)
  • range(range)
  • lon(lon)
  • Millivolts at internal ADC input (0 to 2500)(background_light)
  • Percentage of nominal factory setting (0 to 999%)(receiver_sensitivity)
  • Vertical visibility(vertical_visibility)
  • Laser temperature(laser_temperature)
  • Altitude of highest signal(alt_highest_signal)
  • 6 character string describing instrument measurement parameters(measurement_parameters)
  • Second lowest cloud base height(second_cbh)
  • GPS raw data filename(filename)
  • Degrees from vertical (0 to +90)(tilt_angle)
  • Detection status. See details(detection_status)
  • lat(lat)
  • Dummy altitude for Zeb(alt)
  • Millivolts at internal ADC input(window_contamination)
  • Backscatter sum(sum_backscatter)


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DQRID : D060517.3
Start DateStart TimeEnd DateEnd Time
05/13/2006224905/15/20060410
Subject:
TWP/VCEIL/C2 - Vceil computer disconnected
DataStreams:twpvceil25kC2.b1
Description:
VCEIL computer was disconnected during this time period.
Measurements:twpvceil25kC2.b1:
  • Aerosol backscatter coefficient at 355 nm(backscatter)
  • Flag indicating aeri retrieval status(status_flag)
  • Percentage of nominal factory setting (0 to 999%)(laser_pulse_energy)
  • Third cloud base height(third_cbh)
  • Time offset of tweaks from base_time(time_offset)
  • base time(base_time)
  • Lowest cloud base height detected.(first_cbh)
  • Warning and alarm status bits(status_string)
  • range(range)
  • Millivolts at internal ADC input (0 to 2500)(background_light)
  • Percentage of nominal factory setting (0 to 999%)(receiver_sensitivity)
  • Vertical visibility(vertical_visibility)
  • Laser temperature(laser_temperature)
  • Altitude of highest signal(alt_highest_signal)
  • 6 character string describing instrument measurement parameters(measurement_parameters)
  • Second lowest cloud base height(second_cbh)
  • GPS raw data filename(filename)
  • Degrees from vertical (0 to +90)(tilt_angle)
  • Detection status. See details(detection_status)
  • Millivolts at internal ADC input(window_contamination)
  • Backscatter sum(sum_backscatter)


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DQRID : D060717.5
Start DateStart TimeEnd DateEnd Time
05/13/2006222407/17/20061912
Subject:
TWP/VCEIL/C2 - Time offset
DataStreams:twpvceil25kC2.b1
Description:
On 7/14/2006, I found that the ceilometer time was 8m 36s slow, the PC time display (lower 
right taskbar) was frozen at "22:24", and AboutTime was not running. Corrected it on 
7/17 by running AboutTime so that 19:03:29 became 19:12:05. This also corrected the frozen 
display on the Windows98 taskbar. 

I am not sure of the start time of this problem but there were several other Windows 
related issues that had to be corrected on 5/14 with indications of inappropriate access via 
Remote Administrator on 5/13. I do not know if the time offset was a sudden or gradual 
change.
Measurements:twpvceil25kC2.b1:
  • Aerosol backscatter coefficient at 355 nm(backscatter)
  • Flag indicating aeri retrieval status(status_flag)
  • Percentage of nominal factory setting (0 to 999%)(laser_pulse_energy)
  • Third cloud base height(third_cbh)
  • Time offset of tweaks from base_time(time_offset)
  • base time(base_time)
  • Lowest cloud base height detected.(first_cbh)
  • Warning and alarm status bits(status_string)
  • range(range)
  • Millivolts at internal ADC input (0 to 2500)(background_light)
  • Percentage of nominal factory setting (0 to 999%)(receiver_sensitivity)
  • Vertical visibility(vertical_visibility)
  • Laser temperature(laser_temperature)
  • Altitude of highest signal(alt_highest_signal)
  • 6 character string describing instrument measurement parameters(measurement_parameters)
  • Second lowest cloud base height(second_cbh)
  • Degrees from vertical (0 to +90)(tilt_angle)
  • Detection status. See details(detection_status)
  • Millivolts at internal ADC input(window_contamination)
  • Backscatter sum(sum_backscatter)


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DQRID : D070201.2
Start DateStart TimeEnd DateEnd Time
12/13/2006000002/05/20070028
Subject:
TWP/VCEIL/C2 - optical cross-talk compensation
DataStreams:twpvceil25kC2.b1
Description:
The ceilometer gave frequent optical cross-talk compensation warnings, was insensitive to 
high clouds, and the tropics window was deteriorated. The instrument was replaced with a 
spare.
Measurements:twpvceil25kC2.b1:
  • Aerosol backscatter coefficient at 355 nm(backscatter)
  • Vertical visibility(vertical_visibility)
  • Altitude of highest signal(alt_highest_signal)
  • Third cloud base height(third_cbh)
  • Second lowest cloud base height(second_cbh)
  • Millivolts at internal ADC input(window_contamination)


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DQRID : D070329.1
Start DateStart TimeEnd DateEnd Time
03/11/2007212004/17/20072325
Subject:
TWP/VCEIL/C2 - Receiver failure
DataStreams:twpvceil25kC2.b1
Description:
The receiver failed and the instrument was replaced.  Data during the specified period are 
not valid.
Measurements:twpvceil25kC2.b1:
  • Aerosol backscatter coefficient at 355 nm(backscatter)
  • Vertical visibility(vertical_visibility)
  • Altitude of highest signal(alt_highest_signal)
  • Third cloud base height(third_cbh)
  • Second lowest cloud base height(second_cbh)
  • Lowest cloud base height detected.(first_cbh)
  • Millivolts at internal ADC input (0 to 2500)(background_light)
  • Backscatter sum(sum_backscatter)


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