DQR ID | Subject | Data Streams Affected |
---|---|---|
D051209.4 | TWP/VCEIL/C3 - Degraded hardware | twpvceil25kC3.b1 |
D051216.6 | TWP/VCEIL/C3 - ceilometer lost sensitivity | twpvceil25kC3.b1 |
D060113.1 | TWP/VCEIL/C3 - low receiver sensitivity | twpvceil25kC3.b1 |
D061220.34 | TWP/VCEIL/C3 - standard instrument installed | twpvceil25kC3.b1 |
D070201.1 | TWP/VCEIL/C3 - Reduced sensitivity to high clouds | twpvceil25kC3.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 |
---|---|---|---|
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 |
---|---|---|---|
05/18/2006 | 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:
|