DQR ID | Subject | Data Streams Affected |
---|---|---|
D050310.1 | TWP/VCEIL/C2 - Ceilometer failure | twpvceil25kC2.00, twpvceil25kC2.b1 |
D051209.4 | TWP/VCEIL/C3 - Degraded hardware | twpvceil25kC3.b1 |
D051209.5 | TWP/VCEIL/C2 - occasional communication fault | twpvceil25kC2.b1 |
D051216.6 | TWP/VCEIL/C3 - ceilometer lost sensitivity | twpvceil25kC3.b1 |
D060113.1 | TWP/VCEIL/C3 - low receiver sensitivity | twpvceil25kC3.b1 |
D060517.3 | TWP/VCEIL/C2 - Vceil computer disconnected | twpvceil25kC2.b1 |
D060717.5 | TWP/VCEIL/C2 - Time offset | twpvceil25kC2.b1 |
D061220.34 | TWP/VCEIL/C3 - standard instrument installed | twpvceil25kC3.b1 |
D070201.1 | TWP/VCEIL/C3 - Reduced sensitivity to high clouds | twpvceil25kC3.b1 |
D070201.2 | TWP/VCEIL/C2 - optical cross-talk compensation | twpvceil25kC2.b1 |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/26/2005 | 0600 | 04/01/2005 | 0007 |
Subject: | TWP/VCEIL/C2 - Ceilometer failure |
DataStreams: | twpvceil25kC2.00, twpvceil25kC2.b1 |
Description: | Large data gaps began occurring frequently at the TWP Nauru site 26 February at 06Z. Prior to 25 February, optical cross talk errors had been observed. Beginning on 25 February, data errors were observed. By 26 February, these errors were exhibiting themselves as extended data gaps. These gaps became increasingly frequent between 2/26 and 3/4. All data are missing after 20050304.1550. The instrument was replaced on 29 March and after some subsequent configuration work, the instrument was revived just after 00Z on 1 April. |
Measurements: | twpvceil25kC2.00:
twpvceil25kC2.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/16/2005 | 0000 | 12/12/2005 | 0505 |
Subject: | TWP/VCEIL/C3 - Degraded hardware |
DataStreams: | twpvceil25kC3.b1 |
Description: | It appears that the sensitivity of the Darwin ceilometer was degrading over a few month period leading up to September 2005. Beginning on September 16, 2005, the instrument shifted to a particularly bad state. Looking at the backscatter data, I do not see nearly as great a day-night difference in the background as I expect and there is very little sensitivity to clouds. There was cross talk error noted with that instrument. The ceilometer was replaced on December 12. |
Measurements: | twpvceil25kC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
08/30/2005 | 2000 | 12/12/2005 | 0346 |
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:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/16/2005 | 2300 | 12/12/2005 | 0500 |
Subject: | TWP/VCEIL/C3 - ceilometer lost sensitivity |
DataStreams: | twpvceil25kC3.b1 |
Description: | ceilometer sesitivity decreased suddenly and only very strong cloud reflections are observed in the first kilometer. |
Measurements: | twpvceil25kC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/12/2005 | 0555 | 05/18/2006 | 2300 |
Subject: | TWP/VCEIL/C3 - low receiver sensitivity |
DataStreams: | twpvceil25kC3.b1 |
Description: | The ceilometer reported frequent receiver alarms. There are periods when the receiver sensitivity dropped to about 50%. The problem was corrected by replacing the instrument with a spare. |
Measurements: | twpvceil25kC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
05/13/2006 | 2249 | 05/15/2006 | 0410 |
Subject: | TWP/VCEIL/C2 - Vceil computer disconnected |
DataStreams: | twpvceil25kC2.b1 |
Description: | VCEIL computer was disconnected during this time period. |
Measurements: | twpvceil25kC2.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
05/13/2006 | 2224 | 07/17/2006 | 1912 |
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:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
05/18/2006 | 2300 | 12/20/2006 | 0400 |
Subject: | TWP/VCEIL/C3 - standard instrument installed |
DataStreams: | twpvceil25kC3.b1 |
Description: | A spare ceilometer without the tropics window option was installed. The manufacturer recommends the tropics window be used at +/- 25 deg lattitude to prevent direct solar radiation into the laser optics when the instrument pointed at zenith. No significant signal degradation is apparent during the autumnal equinox but, as a precaution, the unit was replaced with the original with a tropics window. |
Measurements: | twpvceil25kC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/20/2006 | 0401 | 01/12/2007 | 0120 |
Subject: | TWP/VCEIL/C3 - Reduced sensitivity to high clouds |
DataStreams: | twpvceil25kC3.b1 |
Description: | The instrument produced a significant number of optical cross-talk warnings and displayed a reduced capacity to detect high clouds. The internal cables were inspected, the compensation fiber and optics monitor were replaced, the crosstalk compensation was adjusted, and the system tested with an optical termination hood, all with no improvement. While waiting for a new receiver board, receiver ribbon cable, and compensation fiber cable from Vaisala, a spare ceilometer with a standard, "non-tropics", window was installed. |
Measurements: | twpvceil25kC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/13/2006 | 0000 | 02/05/2007 | 0028 |
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:
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