DQR ID | Subject | Data Streams Affected |
---|---|---|
D030214.1 | SGP/MWR/B4/C1 - LOS cycle skipping | sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D030312.3 | SGP/MWR/B4 - Intermittent Negative Sky Brightness Temperatures | sgpmwrlosB4.a1, sgpmwrlosB4.b1 |
D030822.3 | SGP/MWR/B4 - min/max/delta values incorrect | sgpmwrlosB4.b1 |
D031106.2 | SGP/MWR/B4 - no air temperature signal | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
D041021.3 | SGP/MWR/B4 - Heater problem | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
D050725.3 | SGP/MWR/B4 - Reprocess: Revised Retrieval Coefficients | sgp5mwravgB4.c1, sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrtipB4.a1, sgpqmemwrcolB4.c1 |
D050927.3 | SGP/MWR/B4 - New software version (4.15) installed | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
D060420.1 | SGP/MWR/B4 - Reprocess: wrong retrievals | sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrtipB4.a1, sgpqmemwrcolB4.c1 |
D080701.2 | SGP/MWR/B4 - Missing data | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
D090115.2 | SGP/MWR/B4 - Occasional spikes in data | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
07/31/2002 | 2034 | 11/05/2002 | 1815 |
Subject: | SGP/MWR/B4/C1 - LOS cycle skipping |
DataStreams: | sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | When MWR software version 4.12 was installed at the SGP, it was observed that the MWRs at CF and BF4 skip line-of-sight (LOS) observing cycles. In LOS mode, the software begins an observing cycle at 0, 20, and 40 seconds after the minute to provide 3 LOS cycles per minute. If a cycle is delayed so that it takes more than 20 seconds to complete, then the next start time is missed, the cycle is skipped, and the data that would have been acquired are lost. It was demonstrated that the interaction with the IRT at CF slowed the MWR observing cycle noticeably and contributed significantly to the LOS cycle skipping. The IRT was removed from the MWR on 5 November 2002 and the LOS cycle skipping at the CF was resolved. The IRT data are now available in a new separate datastream: sgpirtC1.a1 (and soon sgpirt2sC1.a1). The BF4 cycle skipping may have resulted from a combination of an additional air temperature sensor on this instrument and the use of a fiber optic cable. However, the cycle skipping on this instrument appears to have abated without modifications to the instrument configuration. |
Measurements: | sgpmwrlosB4.b1:
sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
sgpmwrlosB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/01/2000 | 2100 | 07/09/2002 | 1700 |
Subject: | SGP/MWR/B4 - Intermittent Negative Sky Brightness Temperatures |
DataStreams: | sgpmwrlosB4.a1, sgpmwrlosB4.b1 |
Description: | Several related and recurring problems with the SGP MWRs have been reported dating back to 1999. These problems were due to the occurrence of blackbody signals (in counts) that were half of those expected. The symptoms included noisy data (especially at Purcell), spikes in the data (especially at Vici), negative brightness temperatures, and apparent loss of serial communication between the computer and the radiometer, which results in a self-termination of the MWR program (especially at the CF). Because these all initially appeared to be hardware-related problems, the instrument mentor and SGP site operations personnel (1) repeatedly cleaned and replaced the fiber optic comm. components, (2) swapped radiometers, (3) sent radiometers back to Radiometrics for evaluation (which has not revealed any instrument problems), and (4) reconfigured the computer's operating system. Despite several attempts to isolate and correct it, the problem persisted. It became apparent that some component of the Windows98 configuration conflicted with the DOS-based MWR program or affected the serial port or the contents of the serial port buffer. This problem was finally corrected by upgrading the MWR software with a new Windows-compatible program. |
Measurements: | sgpmwrlosB4.b1:
sgpmwrlosB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/28/1998 | 0000 | 02/10/2003 | 2359 |
Subject: | SGP/MWR/B4 - min/max/delta values incorrect |
DataStreams: | sgpmwrlosB4.b1 |
Description: | The values of valid_min, valid_max, and valid_delta for fields tkxc and tknd were incorrect. They should be 303, 333, and 0.5 K, respectively. |
Measurements: | sgpmwrlosB4.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/14/2003 | 1741 | 12/23/2004 | 2025 |
Subject: | SGP/MWR/B4 - no air temperature signal |
DataStreams: | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
Description: | When the new blower was upgraded by Radiometrics and reinstalled on the MWR, the air temperature sensor failed to properly report. It was determined that the wires carrying the signal to the analog board did not conform to the standard expected by the upgraded blower. The problem was corrected by changing the wiring and modifying the MWR software to read the signal from the appropriate corresponding channel. |
Measurements: | sgpmwrlosB4.b1:
sgpmwrtipB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/10/2004 | 1930 | 11/23/2004 | 1720 |
Subject: | SGP/MWR/B4 - Heater problem |
DataStreams: | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
Description: | The heater does not appear to be operating properly when moisture is detected. The problem was corrected by adjusting the heater sensivity. |
Measurements: | sgpmwrlosB4.b1:
sgpmwrtipB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/15/2002 | 2300 | 06/24/2005 | 2100 |
Subject: | SGP/MWR/B4 - Reprocess: Revised Retrieval Coefficients |
DataStreams: | sgp5mwravgB4.c1, sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrtipB4.a1, sgpqmemwrcolB4.c1 |
Description: | IN THE BEGINNING (June 1992), the retrieval coefficients used to derive the precipitable water vapor (PWV) and liquid water path (LWP) from the MWR brightness temperatures were based on the Liebe and Layton (1987) water vapor and oxygen absorption model and the Grant (1957) liquid water absorption model. Following the SHEBA experience, revised retrievals based on the more recent Rosenkranz (1998) water vapor and oxygen absorption models and the Liebe (1991) liquid waer absorption model were developed. The Rosenkranz water vapor absorption model resulted a 2 percent increase in PWV relative to the earlier Liebe and Layton model. The Liebe liquid water absorption model decreased the LWP by 10% relative to the Grant model. However, the increased oxygen absorption caused a 0.02-0.03 mm (20-30 g/m2) reduction in LWP, which was particularly significant for low LWP conditions (i.e. thin clouds encountered at SHEBA). Recently, it has been shown (Liljegren, Boukabara, Cady-Pereira, and Clough, TGARS v. 43, pp 1102-1108, 2005) that the half-width of the 22 GHz water vapor line from the HITRAN compilation, which is 5 percent smaller than the Liebe and Dillon (1969) half-width used in Rosenkranz (1998), provided a better fit to the microwave brightness temperature measurements at 5 frequencies in the range 22-30 GHz, and yielded more accurate retrievals. Accordingly, revised MWR retrieval coefficients have been developed using MONORTM, which utilizes the HITRAN compilation for its spectroscopic parameters. These new retrievals provide 3 percent less PWV and 2.6 percent greater LWP than the previous retrievals based on Rosenkranz (1998). Although the MWR data will be reprocessed to apply the new monortm-based retrievals, for most purposes it will be sufficient to correct the data using the following factors: PWV_MONORTM = 0.9695 * PWV_ROSENKRANZ LWP_MONORTM = 1.026 * LWP_ROSENKRANZ The Rosenkranz-based retrieval coefficients became active at SGP.B4 20020415.2300. The MONORTM-based retrieval coefficients became active at SGP.B4 20050624.2100. Note: a reprocessing effort is already underway to apply the Rosenkranz-based retrieval coefficients to all MWR prior to April 2002. An additional reprocessing task will be undertaken to apply the MONORTM retrieval to all MWR data when the first is completed. Read reprocessing comments in the netcdf file header carefully to ensure you are aware which retrieval is in play. |
Measurements: | sgpmwrlosB4.b1:
sgpmwrtipB4.a1:
sgpqmemwrcolB4.c1:
sgp5mwravgB4.c1:
sgpmwrlosB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
07/09/2002 | 1700 | 09/13/2005 | 2121 |
Subject: | SGP/MWR/B4 - New software version (4.15) installed |
DataStreams: | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
Description: | A problem began with the installation of MWR.EXE version 4.12 in July 2002. The software had been upgraded from a "DOS" to a "Windows"-compiled program to address an earlier problem. The software upgrade corrected the earlier problem but introduced a new one that caused line-of-sight observing cycles to be skipped, a 15% reduction in the number of tip curves, and saturation of CPU usage. Software versions 4.13 and 4.14 also produced these problems. The new MWR software, version 4.15, was installed on 9/13/2005. As a consequence of this upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s. |
Measurements: | sgpmwrlosB4.b1:
sgpmwrtipB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/28/2004 | 1729 | 11/23/2004 | 1713 |
Subject: | SGP/MWR/B4 - Reprocess: wrong retrievals |
DataStreams: | sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrtipB4.a1, sgpqmemwrcolB4.c1 |
Description: | When the computer and core configuration were upgraded, retrieval coefficients for BF1 were accidently included in the configuration file. The correct coefficients for BF4 were applied when the software was upgraded to ver. 4.14 and the configuration file was updated. |
Measurements: | sgpmwrlosB4.b1:
sgpmwrtipB4.a1:
sgpqmemwrcolB4.c1:
sgpmwrlosB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
07/24/1999 | 2000 | 07/26/1999 | 1651 |
07/30/1999 | 2100 | 08/01/1999 | 1452 |
06/01/2000 | 1839 | 06/05/2000 | 1800 |
07/03/2000 | 2239 | 07/05/2000 | 1651 |
08/05/2000 | 1736 | 08/07/2000 | 1857 |
08/09/2000 | 1300 | 09/19/2000 | 1808 |
09/23/2000 | 0436 | 09/25/2000 | 1257 |
12/31/2000 | 1645 | 01/02/2001 | 1700 |
07/13/2001 | 1550 | 07/16/2001 | 1515 |
01/31/2002 | 0047 | 02/05/2002 | 1657 |
06/28/2002 | 1023 | 07/09/2002 | 1650 |
12/14/2002 | 0700 | 12/20/2002 | 1719 |
03/04/2003 | 1735 | 03/07/2003 | 1708 |
06/06/2003 | 0046 | 06/09/2003 | 1703 |
09/23/2003 | 1948 | 09/25/2003 | 1842 |
10/09/2003 | 2224 | 10/14/2003 | 1741 |
12/15/2003 | 1130 | 12/18/2003 | 1716 |
05/23/2004 | 2003 | 05/25/2004 | 1729 |
12/24/2004 | 0718 | 12/27/2004 | 1435 |
06/18/2005 | 1521 | 06/20/2005 | 1304 |
09/30/2005 | 0405 | 10/03/2005 | 1359 |
10/07/2005 | 2313 | 10/11/2005 | 1400 |
10/12/2005 | 0041 | 10/14/2005 | 1318 |
10/14/2005 | 1344 | 10/28/2005 | 1537 |
10/28/2005 | 2356 | 10/31/2005 | 1756 |
11/05/2005 | 0214 | 11/07/2005 | 1529 |
11/17/2005 | 1517 | 06/11/2007 | 1855 |
05/27/2008 | 0429 | 06/03/2008 | 1714 |
10/03/2008 | 0520 | 10/06/2008 | 1205 |
10/31/2008 | 1413 | 11/03/2008 | 1318 |
Subject: | SGP/MWR/B4 - Missing data |
DataStreams: | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
Description: | Data are missing and unrecoverable. |
Measurements: | sgpmwrlosB4.b1:
sgpmwrtipB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/07/2008 | 0000 | 12/29/2008 | 0000 |
Subject: | SGP/MWR/B4 - Occasional spikes in data |
DataStreams: | sgpmwrlosB4.b1, sgpmwrtipB4.a1 |
Description: | Between 12/7 and 12/29 the 23.8-GHz brightness temperature was affected by the presence of spikes due to interference that was more active between 12/7 and 12/15 and then diminished. The spikes affect the PWV and the LWP as well. Spikes happen two or three times a day. Review the data to determine where the spikes happen and disregard or filter out the affected points. |
Measurements: | sgpmwrlosB4.b1:
sgpmwrtipB4.a1:
|