DQR ID | Subject | Data Streams Affected |
---|---|---|
D060113.1 | TWP/VCEIL/C3 - low receiver sensitivity | twpvceil25kC3.b1 |
D060224.3 | TWP/MPL/C3 - Temporary laser failure | twpmplC3.00, twpmplC3.a1 |
D060227.1 | TWP/MPL/C3 - Backscatter profiles are inaccurate due to computer HD corruption. | twpmplC3.00, twpmplC3.a1 |
D060426.8 | TWP/SMET/C3 - ORG data noisy due to degraded ground | twpsmet60sC3.b1 |
D060629.1 | TWP/MMCR/C3 - Diminished Reflectivity Sensitivity | twpmmcrmomC3.b1, twpmmcrspecmomC3.a0 |
D061011.4 | TWP/SMET/C3 - Reprocess: Tipping bucket rain gauge added | twpsmet60sC3.b1 |
D070112.3 | TWP/MMCR/C3 - Reprocess: Height Error | twpmmcrmomC3.00, twpmmcrmomC3.b1, twpmmcrspecmomC3.a0 |
D080529.2 | TWP/MPL/C3 - Intermittent Double Pulse from laser | twpmplC3.a1 |
D081022.8 | TWP/SMET/C3 - Wind Speed data contain offset due to induced voltage | twpsmet60sC3.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 |
---|---|---|---|
02/20/2006 | 0600 | 02/23/2006 | 0600 |
Subject: | TWP/MPL/C3 - Temporary laser failure |
DataStreams: | twpmplC3.00, twpmplC3.a1 |
Description: | No backscatter information is in the data. The backscatter data in the files during this time is solar background information only. The laser turned it's self off, reason: unknown. A power cycle of the entire system corrected the problem. |
Measurements: | twpmplC3.00:
twpmplC3.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/24/2006 | 0600 | 02/27/2006 | 0700 |
Subject: | TWP/MPL/C3 - Backscatter profiles are inaccurate due to computer HD corruption. |
DataStreams: | twpmplC3.00, twpmplC3.a1 |
Description: | The data shows a consistent cloud deck at 7.5km with what appears to be a duplication of the data from ground zero. The temperature and energy monitor values are also affected. The computer was found with multiple corruption problems. These corruptions may have cause the ghost data at 7.5km. A chkdsk was performed which appears to have corrected the problem. |
Measurements: | twpmplC3.00:
twpmplC3.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/01/2005 | 0000 | 08/24/2006 | 2359 |
Subject: | TWP/SMET/C3 - ORG data noisy due to degraded ground |
DataStreams: | twpsmet60sC3.b1 |
Description: | SMET Rain Data began to be noisy during December 2005 and the problem slowly became worse over time so that in February 2006 the ORG was reporting with a constant background value of around 0.10 mm/hr rain rate. ORG voltage showed a near constant value above the 85mV threshold. The ground for the ORG had become degraded and was lost due to corrosion. |
Measurements: | twpsmet60sC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/02/2005 | 0000 | 07/18/2006 | 2359 |
Subject: | TWP/MMCR/C3 - Diminished Reflectivity Sensitivity |
DataStreams: | twpmmcrmomC3.b1, twpmmcrspecmomC3.a0 |
Description: | Radar sensitivity was diminished by approximately 15 - 20 dBZ during this period. The result is that upper level cloud tops may be missed and thin clouds, particularly thin cirrus, may not be detected during this period. Reflectivity was correctly calibrated, so values are correct where signals were detected. The problem was caused by lightning damage to the low noise amplifier (LNA). The LNA was replaced on 20060718. |
Measurements: | twpmmcrspecmomC3.a0:
twpmmcrmomC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
03/12/2002 | 0000 | 09/26/2006 | 1435 |
Subject: | TWP/SMET/C3 - Reprocess: Tipping bucket rain gauge added |
DataStreams: | twpsmet60sC3.b1 |
Description: | A tipping bucket rain gauge was added to the SMET suite of instruments effective 20060926. Two new variables (count and rain amount) were added at the end of the twpsmet60sC1.b1 datastream. When reprocessing of this datastream occurs these variables will be added with -9999 (missing) as the value for dates prior to gauge installation. |
Measurements: | twpsmet60sC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
11/04/2005 | 0500 | 01/10/2007 | 2000 |
Subject: | TWP/MMCR/C3 - Reprocess: Height Error |
DataStreams: | twpmmcrmomC3.00, twpmmcrmomC3.b1, twpmmcrspecmomC3.a0 |
Description: | A timing error was found in the PIRAQ MMCR's. It resulted in recorded heights being too high for each radar mode by the following amounts: Mode 1: 24.8756 m too high Mode 2: 25.6249 m too high Mode 3: 33.1176 m too high Mode 4: 33.1176 m too high Range gate spacing was not affected. |
Measurements: | twpmmcrspecmomC3.a0:
twpmmcrmomC3.00:
twpmmcrmomC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/01/2005 | 0000 | 08/24/2006 | 2359 |
Subject: | TWP/MPL/C3 - Intermittent Double Pulse from laser |
DataStreams: | twpmplC3.a1 |
Description: | When Spectra Physics discontinued support for their laser diode power supply, an alternative was need 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. |
Measurements: | twpmplC3.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
03/12/2004 | 0000 | 10/17/2008 | 0627 |
Subject: | TWP/SMET/C3 - Wind Speed data contain offset due to induced voltage |
DataStreams: | twpsmet60sC3.b1 |
Description: | The marine model of the RM Young wind sensor needs twisted pair shielded cable. The manufacturer did not originally supply the pigtail with twisted pair shielded cable. Use of twisted pair shielded cable for the rest of the cable run to the logger was also not specified. This caused an induced voltage in the wind speed line from the wind direction excitation. The induced voltage varied from sensor to sensor and probably changed anytime the cable was replaced or parts of the wind sensor were repaired or replaced. The induced voltage has been seen to vary from 0.15 m/s to as much as 1.08 m/s. |
Measurements: | twpsmet60sC3.b1:
|