DQR ID | Subject | Data Streams Affected |
---|---|---|
D010202.8 | NSA/MWR/C2 - Wet-window flag incorrectly set | nsamwrlosC2.b1, nsamwrtipC2.a1 |
D010308.1 | NSA/MWR/C2 - Elevated sky brightness temperatures | nsamwrlosC2.b1, nsamwrtipC2.a1 |
D010504.2 | NSA/MWR/C2 - Missing data | nsamwrlosC2.b1, nsamwrtipC2.a1 |
D020824.4 | NSA/MWR/C2 - Instrument Maintenance | nsamwrlosC2.b1 |
D021004.17 | TWP/MWR/C3 - Elevated Skybrightness Temperatures | twpmwrlosC3.a1, twpmwrlosC3.b1 |
D021004.18 | TWP/MWR/C3 - Wet Window Flag not correct | twpmwrlosC3.a1, twpmwrlosC3.b1, twpmwrtipC3.a1 |
D030312.10 | SGP/MWR/C1 - Intermittent Negative Sky Brightness Temperatures | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D030312.7 | NSA/MWR/C2 - Intermittent Negative Sky Brightness Temperatures | nsamwrlosC2.b1 |
D030312.8 | TWP/MWR/C3 - Intermittent Negative Sky Brightness Temperatures | twpmwrlosC3.a1, twpmwrlosC3.b1 |
D030724.1 | NSA/MWR/C2 - Thermally unstable | nsamwrlosC2.b1 |
D030822.11 | TWP/MWR/C3 - min/max/delta values incorrect | twpmwrlosC3.b1 |
D040102.4 | NSA/MWR/C2 - Heater problem | nsamwrlosC2.b1, nsamwrtipC2.a1 |
D050202.1 | NSA/MWR/C2 - no air temperature signal | nsamwrlosC2.b1, nsamwrtipC2.a1 |
D050617.1 | PYE/MWR/M1 - Instrument computer locked up | pyemwrlosM1.b1 |
D050722.1 | SGP/MWR/C1 - REPROCESS - Revised Retrieval Coefficients | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipC1.a1, sgpqmemwrcolC1.c1 |
D050725.11 | TWP/MWR/C3 - Reprocess - Revised Retrieval Coefficients | twpmwrlosC3.a1, twpmwrlosC3.b1, twpmwrtipC3.a1 |
D050725.12 | PYE/MWR/M1 - Reprocessed: Revised Retrieval Coefficients | pyemwrlosM1.b1, pyemwrtipM1.a1 |
D050725.8 | NSA/MWR/C2 - Reprocessed: Revised Retrieval Coefficients | nsamwrlosC2.b1, nsamwrtipC2.a1 |
D050726.4 | PYE/MWR/M1 - Reprocessed: Calibration corrected | pyemwrlosM1.b1, pyemwrtipM1.a1 |
D050830.1 | NSA/MWR/C2 - Thermally unstable | nsamwrlosC2.b1, nsamwrtipC2.a1 |
D050915.1 | SGP/MWR/C1 - Instrument noise problem | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
D050927.1 | PYE/MWR/M1 - New software version (4.15) installed | pyemwrlosM1.b1, pyemwrtipM1.a1 |
D050928.4 | NSA/MWR/C2 - New software version (4.15) installed | nsamwrlosC2.b1, nsamwrtipC2.a1 |
D050928.5 | TWP/MWR/C3 - New software version (4.15) installed | twpmwrlosC3.b1, twpmwrtipC3.a1 |
D051114.2 | TWP/MWR/C3 - Instrument failure, Power outage | twpmwrC3.00, twpmwrlosC3.a1, twpmwrlosC3.b1, twpmwrtipC3.a1 |
D051214.1 | TWP/MWR/C3 - REPROCESS- Updated retrieval coefficients | twpmwrlosC3.b1, twpmwrtipC3.a1 |
D060223.1 | NSA/MWR/C2 - Frosting/Condensation | nsamwrC2.00, nsamwrlosC2.b1, nsamwrtipC2.a1 |
D060419.4 | NIM/MWR/M1 - Instrument noise problem/RF interference | nimmwrM1.00, nimmwrlosM1.b1, nimmwrtipM1.a1 |
D060601.1 | TWP/MWR/C3 - Site shutdown | twpmwrC3.00, twpmwrlosC3.a1, twpmwrlosC3.b1, twpmwrtipC3.a1 |
D060718.1 | NIM/MWR/M1 - Reprocessed: Recalibration to correct for occasional overheating. | nimmwrlosM1.b1, nimmwrtipM1.a1 |
D060818.12 | NSA/MWR/C2 - Spikes in air temperature readings | nsamwrlosC2.b1 |
D060927.1 | NIM/MWR/M1 - Sun in field of view of radiometer | nimmwrlosM1.b1 |
D061114.4 | TWP/MWR/C3 - Sun in field of view of radiometer | twpmwrlosC3.b1, twpmwrtipC3.a1 |
D080512.2 | NSA/MWR/C2 - Possible bias on measurements | nsamwrlosC2.b1, nsamwrtipC2.a1 |
D080811.1 | NSA/MWR/C2 - Occasional thermal instability | nsa5mwravgC2.c1, nsamwrlosC2.b1, nsamwrtipC2.a1 |
D080828.1 | HFE/MWR/M1 - Insufficient calibration stability | hfemwrlosM1.b1, hfemwrtipM1.a1 |
D090311.3 | HFE/MWR/M1 - Missing data | hfemwrlosM1.b1, hfemwrtipM1.a1 |
D090522.1 | GRW/MWR/M1 - Loose mirror | grwmwrlosM1.b1, grwmwrtipM1.a1 |
D951005.4 | SGP/MWR/C1 - Valid LWP > 1mm excluded from 5 min avgs | sgp5mwravgC1.c1 |
D960405.1 | SGP/MWR/C1 - Loss of thermal stabilization | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D960422.1 | SGP/MWR/C1 - Radio Frequency Interference during IOP | sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D961120.1 | SGP/MWR/B1/B4/B5/B6/C1 - Thermal Stabilization Adjustment | sgp1mwravgC1.c1, sgp5mwravgB1.c1, sgp5mwravgB4.c1, sgp5mwravgB5.c1, sgp5mwravgB6.c1, sgp5mwravgC1.c1, sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1, sgpmwrlosB6.a0, sgpmwrlosB6.a1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/06/2000 | 0000 | 12/27/2000 | 2359 |
Subject: | NSA/MWR/C2 - Wet-window flag incorrectly set |
DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.a1 |
Description: | The wet window flag is set high more frequently than expected. |
Measurements: | nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/16/2000 | 0554 | 05/11/2000 | 0100 |
02/16/2001 | 1900 | 02/26/2001 | 0020 |
Subject: | NSA/MWR/C2 - Elevated sky brightness temperatures |
DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.a1 |
Description: | The MWR was providing unreasonable values of sky brightness temperatures and values of precipitable water vapor and liquid water path that were about 10 times larger than expected. The problem was corrected when the instrument was power-cycled. The cause of the problem is unknown. |
Measurements: | nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/26/1999 | 0003 | 11/02/1999 | 0008 |
11/09/1999 | 0004 | 12/27/1999 | 0008 |
12/28/1999 | 0004 | 01/08/2000 | 0008 |
01/11/2000 | 0004 | 01/20/2000 | 0428 |
03/11/2000 | 0218 | 03/22/2000 | 0449 |
04/16/2000 | 1536 | 04/18/2000 | 0540 |
06/09/2000 | 0605 | 06/12/2000 | 0408 |
09/28/2000 | 0036 | 09/30/2000 | 0132 |
02/03/2001 | 0208 | 02/05/2001 | 0014 |
06/23/2001 | 0000 | 06/25/2001 | 1820 |
07/01/2001 | 2000 | 07/04/2001 | 1745 |
07/15/2001 | 1800 | 07/17/2001 | 1650 |
11/17/2001 | 0300 | 11/28/2001 | 2332 |
01/21/2002 | 2221 | 01/23/2002 | 0417 |
04/02/2002 | 0000 | 04/03/2002 | 0151 |
04/15/2002 | 2324 | 04/17/2002 | 0108 |
07/21/2002 | 1800 | 07/23/2002 | 0448 |
12/18/2002 | 2218 | 01/28/2003 | 2115 |
02/17/2003 | 1842 | 02/25/2003 | 2044 |
09/22/2005 | 1932 | 10/01/2005 | 1700 |
08/28/2006 | 2000 | 04/15/2008 | 1519 |
11/10/2008 | 1900 | 11/13/2008 | 2309 |
03/25/2009 | 1859 | 03/28/2009 | 2033 |
10/22/2009 | 0716 | 11/16/2009 | 1700 |
Subject: | NSA/MWR/C2 - Missing data |
DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.a1 |
Description: | Data are missing and unrecoverable. |
Measurements: | nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
06/18/2001 | 0200 | 06/18/2001 | 0300 |
Subject: | NSA/MWR/C2 - Instrument Maintenance |
DataStreams: | nsamwrlosC2.b1 |
Description: | Exchange of winter cover caused data corruption. |
Measurements: | nsamwrlosC2.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
07/05/2002 | 2212 | 10/02/2002 | 2359 |
Subject: | TWP/MWR/C3 - Elevated Skybrightness Temperatures |
DataStreams: | twpmwrlosC3.a1, twpmwrlosC3.b1 |
Description: | For an unknown reason, the MWR began to exhibit elevated sky brightness temperatures. This problem was corrected when the instrument was power-cycled. |
Measurements: | twpmwrlosC3.a1:
twpmwrlosC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/28/2002 | 0000 | 10/02/2002 | 2359 |
Subject: | TWP/MWR/C3 - Wet Window Flag not correct |
DataStreams: | twpmwrlosC3.a1, twpmwrlosC3.b1, twpmwrtipC3.a1 |
Description: | The moisture sensor threshold voltage in the MWR configuration file was set to the wrong value for the new heater/blower assembly. This caused the wet window flag to not be set high during times of rain. |
Measurements: | twpmwrlosC3.a1:
twpmwrlosC3.b1:
twpmwrtipC3.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
11/17/1999 | 1800 | 07/31/2002 | 2034 |
Subject: | SGP/MWR/C1 - Intermittent Negative Sky Brightness Temperatures |
DataStreams: | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.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: | sgp5mwravgC1.c1:
sgpmwrlosC1.b1:
sgp1mwravgC1.c1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/15/2000 | 0600 | 09/16/2002 | 1900 |
Subject: | NSA/MWR/C2 - Intermittent Negative Sky Brightness Temperatures |
DataStreams: | nsamwrlosC2.b1 |
Description: | Several related and recurring problems with the 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, spikes in the data, 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. Because these all initially appeared to be hardware-related problems, the instrument mentor and 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 did 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: | nsamwrlosC2.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/27/2002 | 0151 | 10/02/2002 | 2359 |
Subject: | TWP/MWR/C3 - Intermittent Negative Sky Brightness Temperatures |
DataStreams: | twpmwrlosC3.a1, twpmwrlosC3.b1 |
Description: | Several related and recurring problems with the 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, spikes in the data, 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. 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 did 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 (MWR version 4.12). |
Measurements: | twpmwrlosC3.a1:
twpmwrlosC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
06/19/2003 | 2324 | 07/21/2003 | 0824 |
Subject: | NSA/MWR/C2 - Thermally unstable |
DataStreams: | nsamwrlosC2.b1 |
Description: | The MWR became thermally unstable during periods when the ambient temperature exceeded about 28C. This situation was corrected when the mixer temperature was manually increased to about 35C. Data are suspect when the blackbody temperature, tkbb, exceeds 296 K. |
Measurements: | nsamwrlosC2.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/27/2002 | 0152 | 02/09/2003 | 2359 |
Subject: | TWP/MWR/C3 - min/max/delta values incorrect |
DataStreams: | twpmwrlosC3.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: | twpmwrlosC3.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
11/23/2003 | 0000 | 01/09/2004 | 2030 |
Subject: | NSA/MWR/C2 - Heater problem |
DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.a1 |
Description: | The MWR heater did not appear to operate when moisture was present. The heater sensitivity was adjusted. |
Measurements: | nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/25/2003 | 2044 | 11/18/2004 | 2304 |
Subject: | NSA/MWR/C2 - no air temperature signal |
DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.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 modifying the MWR software to read the signal from the appropriate corresponding channel. |
Measurements: | nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
06/09/2005 | 0000 | 06/09/2005 | 1500 |
Subject: | PYE/MWR/M1 - Instrument computer locked up |
DataStreams: | pyemwrlosM1.b1 |
Description: | The MWR computer locked up and required a reboot at 00Z on June 9, 2005. When the program was restarted, water vapor, liquid path, and temps dropped to zero. They did not recover until 15Z the same day. |
Measurements: | pyemwrlosM1.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/16/2002 | 2000 | 06/28/2005 | 2300 |
Subject: | SGP/MWR/C1 - REPROCESS - Revised Retrieval Coefficients |
DataStreams: | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipC1.a1, sgpqmemwrcolC1.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 as follows (BCR 456): SGP/C1 (Lamont) 4/16/2002, 2000 SGP/B1 (Hillsboro) 4/12/2002, 1600 SGP/B4 (Vici) 4/15/2002, 2300 SGP/B5 (Morris) 4/15/2002, 2300 SGP/B6 (Purcell) 4/16/2002, 2200 SGP/E14(Lamont) 4/16/2002, 0000 NSA/C1 (Barrow) 4/25/2002, 1900 NSA/C2 (Atqasuk) 4/18/2002, 1700 TWP/C1 (Manus) 5/04/2002, 0200 TWP/C2 (Nauru) 4/27/2002, 0600 TWP/C3 (Darwin) inception The MONORTM-based retrieval coefficients became active as follows (BCR 984): SGP/C1 (Lamont) 6/28/2005, 2300 SGP/B1 (Hillsboro) 6/24/2005, 2100 SGP/B4 (Vici) 6/24/2005, 2100 SGP/B5 (Morris) 6/24/2005, 2100 SGP/B6 (Purcell) 6/24/2005, 1942 SGP/E14(Lamont) 6/28/2005, 2300 NSA/C1 (Barrow) 6/29/2005, 0000 NSA/C2 (Atqasuk) 6/29/2005, 0000 TWP/C1 (Manus) 6/30/2005, 2100 TWP/C2 (Nauru) 6/30/2005, 2100 TWP/C3 (Darwin) 6/30/2005, 2100 PYE/M1 (Pt. Reyes) 4/08/2005, 1900** ** At Pt. Reyes, the original retrieval coefficients implemented in March 2005 were based on a version of the Rosenkranz model that had been modified to use the HITRAN half-width at 22 GHz and to be consistent with the water vapor continuum in MONORTM. These retrievals yield nearly identical results to the MONORTM retrievals. Therefore the Pt. Reyes data prior to 4/08/2005 may not require reprocessing. |
Measurements: | sgpmwrtipC1.a1:
sgp5mwravgC1.c1:
sgpmwrlosC1.b1:
sgp1mwravgC1.c1:
sgpqmemwrcolC1.c1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/27/2002 | 0151 | 06/30/2005 | 2100 |
Subject: | TWP/MWR/C3 - Reprocess - Revised Retrieval Coefficients |
DataStreams: | twpmwrlosC3.a1, twpmwrlosC3.b1, twpmwrtipC3.a1 |
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 was active at TWP.C3 from inception of the data, 20020227.0151. The MONORTM-based retrieval coefficients became active at TWP.C3 20050630.2100. 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: | twpmwrlosC3.a1:
twpmwrlosC3.b1:
twpmwrtipC3.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/01/2005 | 0700 | 05/06/2005 | 0000 |
Subject: | PYE/MWR/M1 - Reprocessed: Revised Retrieval Coefficients |
DataStreams: | pyemwrlosM1.b1, pyemwrtipM1.a1 |
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 water 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). At Point Reyes, the original coefficients implemented in March 2005 were based on a version of the Rosenkranz model that had been modified to use the HITRAN half-width at 22 GHz and to be consistent with the water vapor continuum in MONORTM. These retrievals yielded nearly identical results to the MONORTM retrievals. The MONORTM-based retrieval coefficients became active at PYE.M1 20050506. Note: The PYE.M1 MWRLOS data for 20050201-20050506 have been reprocessed to apply the MONORTM-based retrievals for all time. The reprocessed data were archived in April 2007. The TIP data have not been reprocessed. |
Measurements: | pyemwrtipM1.a1:
pyemwrlosM1.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/18/1999 | 0000 | 06/29/2005 | 0000 |
Subject: | NSA/MWR/C2 - Reprocessed: Revised Retrieval Coefficients |
DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.a1 |
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 water 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). The Rosenkranz-based retrieval coefficients became active at NSA.C2 20020418.1700. The MONORTM-based retrieval coefficients became active at NSA.C2 20050629.0000. Note: The NSA.C2 MWRLOS data for 19991018-20050630 have been reprocessed to apply the MONORTM-based retrievals for all time. The reprocessed data were archived in March 2007. The TIP data have not been reprocessed. |
Measurements: | nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
05/29/2005 | 0000 | 07/17/2005 | 2100 |
Subject: | PYE/MWR/M1 - Reprocessed: Calibration corrected |
DataStreams: | pyemwrlosM1.b1, pyemwrtipM1.a1 |
Description: | On May 28 1:30 GMT the NFOV radiometer was placed in the field of view of the MWR tip calibration. Almost immediately calibration of the MWR was compromised resulting in incorrect brightness temperatures and overestimation of both PWV and LWP. On July 15 the NFOV radiometer was moved away from the MWR and the instantaneous calibration values jumped back to normal. The median values returned to normal on July 17 around 2100. The LOS data were reprocessed using interpolated values for the calibration coefficients. The reprocessed data are available from the ARM Archive effective December 7, 2005. NOTE: the format of the reprocessed data are slightly different than the format of the original data and the data available before and after the reprocessed data period. The quality of the data are not affected, just the format. The MWRTIP data can not be reprocessed and should be used with caution. |
Measurements: | pyemwrtipM1.a1:
pyemwrlosM1.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
08/12/2005 | 1200 | 08/16/2005 | 2300 |
Subject: | NSA/MWR/C2 - Thermally unstable |
DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.a1 |
Description: | Between 08/12 and 08/17 the instrument displayed some intermittent thermal instability. Measurement accuracy may be degraded during these time periods. Periods of thermal instability may be identified by checking the black body temperature Tkbb. If Tkbb > 303K (30 C) the instrument is unstable. |
Measurements: | nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
07/28/2005 | 1400 | 08/05/2005 | 1700 |
Subject: | SGP/MWR/C1 - Instrument noise problem |
DataStreams: | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
Description: | Various variables including the mixer temperatures were very noisy. After several attempts to fix the problem, the instrument was taken off line and returned to the manufacturer for repair. |
Measurements: | sgpmwrtipC1.a1:
sgp5mwravgC1.c1:
sgpmwrlosC1.b1:
sgp1mwravgC1.c1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/01/2005 | 0700 | 09/13/2005 | 1805 |
Subject: | PYE/MWR/M1 - New software version (4.15) installed |
DataStreams: | pyemwrlosM1.b1, pyemwrtipM1.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: | pyemwrtipM1.a1:
pyemwrlosM1.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/20/2002 | 0251 | 09/15/2005 | 1722 |
Subject: | NSA/MWR/C2 - New software version (4.15) installed |
DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.a1 |
Description: | A problem began with the installation of MWR.EXE version 4.12 in September 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 9/15/2005. As a consequence of this upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s. |
Measurements: | nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/03/2002 | 0000 | 09/20/2005 | 2156 |
Subject: | TWP/MWR/C3 - New software version (4.15) installed |
DataStreams: | twpmwrlosC3.b1, twpmwrtipC3.a1 |
Description: | A problem began with the installation of MWR.EXE version 4.12 in October 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 9/20/2005. As a consequence of this upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s. |
Measurements: | twpmwrlosC3.b1:
twpmwrtipC3.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
11/14/2005 | 0453 | 12/10/2005 | 0000 |
Subject: | TWP/MWR/C3 - Instrument failure, Power outage |
DataStreams: | twpmwrC3.00, twpmwrlosC3.a1, twpmwrlosC3.b1, twpmwrtipC3.a1 |
Description: | A lightning strike sent the MWR offline. The radiometer suffered extensive damage, was removed from the site and sent to the vendor for repair. A spare radiometer was sent to the TWP/C3 site and was installed on 12/07. However, some hardaware communication issues prevented data collection until 12/10. |
Measurements: | twpmwrlosC3.a1:
twpmwrlosC3.b1:
twpmwrtipC3.a1:
twpmwrC3.00:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/27/2002 | 0000 | 12/12/2005 | 1600 |
Subject: | TWP/MWR/C3 - REPROCESS- Updated retrieval coefficients |
DataStreams: | twpmwrlosC3.b1, twpmwrtipC3.a1 |
Description: | The statistical retrieval coefficients currently in use at the Darwin (TWP/C3) site were developed using radiosonde RS80 launched from Manus Island during the TOGA-COARE experiment. Data from Manus Island have minimal seasonality, therefore a single, annual set of coefficients was used at all three sites. Retrievals using these coefficients are sufficiently accurate especially during the local summer months (December-January). However, the Darwin site displays a summer/winter seasonality resulting in larger differences during the southern winter (May- June). Since we now have enough radiosonde soundings (RS80 and RS90) available at the Darwin site, the Darwin coefficients were modified to better reflect the local seasonality. |
Measurements: | twpmwrlosC3.b1:
twpmwrtipC3.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/22/2006 | 0000 | 02/24/2006 | 2359 |
Subject: | NSA/MWR/C2 - Frosting/Condensation |
DataStreams: | nsamwrC2.00, nsamwrlosC2.b1, nsamwrtipC2.a1 |
Description: | Doug reported freezing winds and ice accumulation on the MWR cover and radome. This may affect data quality and calibration. On 2/24 Doug attempted to slowly thaw the cover and clear the window. From 2/22 to 2/24 the LWP and PWV reported by the MWR are near zero. These data are probably affected by the frost accumulated on the radiometer window. |
Measurements: | nsamwrlosC2.b1:
nsamwrC2.00:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
01/15/2006 | 0000 | 01/08/2007 | 0000 |
Subject: | NIM/MWR/M1 - Instrument noise problem/RF interference |
DataStreams: | nimmwrM1.00, nimmwrlosM1.b1, nimmwrtipM1.a1 |
Description: | Data are affected by intermittent spikes that become more frequent starting in March 2006. Spikes affect data mostly around 9 AM and 18:00 PM. The origin of the spikes is probably RF interference. |
Measurements: | nimmwrlosM1.b1:
nimmwrM1.00:
nimmwrtipM1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/24/2006 | 0000 | 04/25/2006 | 2259 |
Subject: | TWP/MWR/C3 - Site shutdown |
DataStreams: | twpmwrC3.00, twpmwrlosC3.a1, twpmwrlosC3.b1, twpmwrtipC3.a1 |
Description: | On 4/24, the site was shutdown in preparation for a cyclone. Instruments were back up on 4/25 at 22:59 |
Measurements: | twpmwrlosC3.a1:
twpmwrlosC3.b1:
twpmwrtipC3.a1:
twpmwrC3.00:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
03/01/2006 | 0000 | 01/08/2007 | 0000 |
Subject: | NIM/MWR/M1 - Reprocessed: Recalibration to correct for occasional overheating. |
DataStreams: | nimmwrlosM1.b1, nimmwrtipM1.a1 |
Description: | The radiometer was intermittently thermally unstable resulting in poor calibrations for four brief time periods. These data have been reprocessed to apply corrected calibrations. The affected time periods were: 20060302-20060303 20060423-20060425 20060512-20060515 20060531-20060603 |
Measurements: | nimmwrlosM1.b1:
nimmwrtipM1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
06/17/2006 | 0000 | 08/01/2006 | 2359 |
Subject: | NSA/MWR/C2 - Spikes in air temperature readings |
DataStreams: | nsamwrlosC2.b1 |
Description: | The tkair variable has occasional spikes due to sensor corrosion. On 8/1, the temperature sensor was replaced. |
Measurements: | nsamwrlosC2.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
08/01/2006 | 0000 | 08/31/2006 | 2300 |
Subject: | NIM/MWR/M1 - Sun in field of view of radiometer |
DataStreams: | nimmwrlosM1.b1 |
Description: | Around 12 pm every day between 8/1 and 8/31 there is an increase in the brightness temperature due to the sun being in the field of view of the radiometer. |
Measurements: | nimmwrlosM1.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/20/2006 | 0000 | 11/09/2006 | 0400 |
10/15/2008 | 0000 | 11/08/2008 | 0000 |
10/15/2009 | 0000 | 11/10/2009 | 0000 |
Subject: | TWP/MWR/C3 - Sun in field of view of radiometer |
DataStreams: | twpmwrlosC3.b1, twpmwrtipC3.a1 |
Description: | Each day from approximately 10/15 to 11/9 around local noon, there is an increase in the brightness temperature due to the sun being in the field of view of the radiometer. |
Measurements: | twpmwrlosC3.b1:
twpmwrtipC3.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/15/2008 | 1500 | 11/16/2009 | 1600 |
Subject: | NSA/MWR/C2 - Possible bias on measurements |
DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.a1 |
Description: | This instrument was refurbished at the the vendor's facility in 2008 and then sent to the SGP for side-by-side comparison with another MWR. During the time the instrument was at the SGP, it was noticed that the 23.8-GHz measurements were slightly warmer than those from radiometer SN10 operating at the SGP Central Facility. A comparison with radiosonde measurements confirmed the slight change in the measurements. An explanation of the bias and comparison with radiosonde measurements and radiometer SN 10 is given in the mentor's monthly data review for the month of April 2008. Since there aren't radiosondes at NSA.C2, it is difficult to work around this problem. Based on comparison at the SGP, the bias in the 23.8-GHz channel was quantified to be ~1.5 K. Users can attempt to subtract this amount from the 23.8-GHz measurements. Alternatively, use the retrieved PWV and LWV keeping in mind that there is a possible overestimation of PWV of ~1 mm. On 11/16/2009 after a hardware failure of the radiometer a spare radiometer (SN15) was installed at the site. |
Measurements: | nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
07/01/2008 | 0000 | 07/15/2008 | 0000 |
Subject: | NSA/MWR/C2 - Occasional thermal instability |
DataStreams: | nsa5mwravgC2.c1, nsamwrlosC2.b1, nsamwrtipC2.a1 |
Description: | Between 7/1 and 7/15 the radiometer experienced a few days of thermal instability. From a review of the data it doesn't appear that the instability has had any major effect. It is not possible to quantify in detail the effect of the instability due to the lack of radiosonde sounding, however users are cautioned that a higher uncertainty may be affecting these data. |
Measurements: | nsa5mwravgC2.c1:
nsamwrlosC2.b1:
nsamwrtipC2.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/06/2008 | 0000 | 09/26/2008 | 2359 |
10/01/2008 | 0000 | 10/06/2008 | 1500 |
10/16/2008 | 0201 | 10/16/2008 | 2359 |
10/20/2008 | 0000 | 10/23/2008 | 2359 |
Subject: | HFE/MWR/M1 - Insufficient calibration stability |
DataStreams: | hfemwrlosM1.b1, hfemwrtipM1.a1 |
Description: | The noise diode temperature suddenly jumped to > 60 C after a power outage. Following additional power problems the noise diode injection temperature drifted fast and the radiometer was not able to calibrate properly. Data during the indicated time periods are poorly calibrated and sometimes erratic. Users should be aware that the accuracy of the measurements is dramatically degraded. Users can use the microwave profiler (MWRP) data to supplement the MWR data. |
Measurements: | hfemwrlosM1.b1:
hfemwrtipM1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/06/2008 | 1501 | 10/16/2008 | 0200 |
10/17/2008 | 0000 | 10/19/2008 | 2359 |
10/24/2008 | 0000 | 10/26/2008 | 2359 |
11/09/2008 | 0000 | 12/28/2008 | 0000 |
Subject: | HFE/MWR/M1 - Missing data |
DataStreams: | hfemwrlosM1.b1, hfemwrtipM1.a1 |
Description: | Data are missing and unrecoverable. |
Measurements: | hfemwrlosM1.b1:
hfemwrtipM1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
05/01/2009 | 0000 | 06/16/2009 | 0745 |
Subject: | GRW/MWR/M1 - Loose mirror |
DataStreams: | grwmwrlosM1.b1, grwmwrtipM1.a1 |
Description: | The data from the MWR were suspicious and became progressively worse. The problem was traced back to the fact that the screw that keeps the mirror in place had become loose and the mirror was freely rotating. The mirror was tightened on 6/9/2009, however the measurements were noisy until 6/16, when the instrument was rebooted and all the connections checked. Measurements between 5/1 and 6/9 should not be used. Data between 6/9 and 6/16 are usable, although they are very noisy. |
Measurements: | grwmwrlosM1.b1:
grwmwrtipM1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/09/1993 | 0005 | 10/12/1995 | 2359 |
Subject: | SGP/MWR/C1 - Valid LWP > 1mm excluded from 5 min avgs |
DataStreams: | sgp5mwravgC1.c1 |
Description: | The limit of maximum valid liquid water path was set at 1 mm. Although this limit was selected 'conservatively' so as to definitely flag precipitation-contaminated data in the 20-second (sgpmwrlos) files, the effect has been to exclude valid liquid water paths greater than 1 mm from the 5-minute averages (sgp5mwravg). The maximum limits for precipitable water vapor (PWV) and liquid water path (LWP) have been removed, and the averaging algorithm instead excludes data on the basis of the brightness temperature flags. These flags are set below a minimum of 2.75 K (cosmic background) and above a maximum of 100 K (precipitation). |
Measurements: | sgp5mwravgC1.c1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
08/19/1995 | 0000 | 08/20/1995 | 2359 |
08/26/1995 | 0000 | 09/04/1995 | 2359 |
07/01/1996 | 1825 | 07/23/1996 | 2300 |
Subject: | SGP/MWR/C1 - Loss of thermal stabilization |
DataStreams: | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | Periodically during August and September 1995 all microwave radiometers at the SGP CART generated error messages in the Site Operations Log like: Time: Sat Aug 19 18:41:20 1995 MWRLOS.C1, tkxc: Value above Maximum. This indicates that the temperature of the microwave hardware (specifically, the cross-coupler or "xc") exceeded its controlled temperature (47-52 deg C) at which point it was no longer thermally stabilized and the gain was uncontrolled. During these periods which typically last about 8 hours from about local noon until about sunset the data behave anomalously and should be considered invalid. Specifically the precipitable water vapor increases and the liquid water path decreases (and becomes SIGNIFICANTLY NEGATIVE (-0.1 mm) on clear sky days). The RMS noise level in the data also increases sharply. The 'Tkxc' field appears ONLY in the a0-level data and does NOT appear in either the a1 (mwrlos) or c1 (mwr5avg) files. Therefore THESE ANOMALOUS VALUES HAVE BEEN INCLUDED IN THE 5-MINUTE AVERAGES. The microwave hardware is thermally stabilized to about +/- 0.1 deg C by resistive heating. When the internal temperature rises above the set point the thermal stabilization of the instrument gain is lost. >From an examination of the component temperature data it appears that increasing the set point temperature to about 55 deg C (328 K) would prevent a re-ocurrance of this problem at the SGP. The manufacturer, Radiometrics, concurs that raising the set point will fix this problem and will not cause other problems. I will have to carefully examine the MCTEX data to determine whether this will be a problem for the TWP. The manufacturer and I had discussed this possibility prior to building the TWP MWRs (S/N 015, 016, and 017) and those instruments have set points above 50 deg C. Note that MWR 018 has a set point near 52 deg C (like the TWP models) but it still experienced a few loss-of-stabilization events. Note that the instruments with the lowest set points had the most loss-of-stabilization events. |
Measurements: | sgp5mwravgC1.c1:
sgpmwrlosC1.b1:
sgp1mwravgC1.c1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/09/1996 | 1337 | 04/09/1996 | 1834 |
04/10/1996 | 0625 | 04/10/1996 | 1823 |
04/11/1996 | 1149 | 04/11/1996 | 1649 |
04/12/1996 | 0917 | 04/12/1996 | 1858 |
04/13/1996 | 0605 | 04/13/1996 | 1801 |
Subject: | SGP/MWR/C1 - Radio Frequency Interference during IOP |
DataStreams: | sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | During the specified times a strong, continuous signal was measured by the 31.4 GHz of the MWR. The signal was present in all 31.4 GHz measurements including the sky measurement, the internal reference target measurement, and the measurement of the internal noise injection source from which the instantaneous instrument gain is computed. The source of the interference has not yet been identified. Because the gain is computed using the difference of the noise injection and target measurements, and because the sky brightness temperature is computed relative to the internal target temperature, the data appear anomalous only for a period of an hour after the interference starts and ends. This is due to the low pass filter applied to the instantaneous gain. However the data should be considered invalid or at least questionable during the entire period for which the interference was present. |
Measurements: | sgp5mwravgC1.c1:
sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
08/01/1996 | 0000 | 08/31/1996 | 2359 |
Subject: | SGP/MWR/B1/B4/B5/B6/C1 - Thermal Stabilization Adjustment |
DataStreams: | sgp1mwravgC1.c1, sgp5mwravgB1.c1, sgp5mwravgB4.c1, sgp5mwravgB5.c1, sgp5mwravgB6.c1, sgp5mwravgC1.c1, sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1, sgpmwrlosB6.a0, sgpmwrlosB6.a1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | In order to correct a thermal stabilization problem identified earlier I adjusted the thermal set point of the microwave radiometers at the SGP upward from 48-50 deg C to 55 deg C in early August 1996 according to the schedule given below. B6 5 August 1996 C1 6 August 1996 B1 7 August 1996 B5 8 August 1996 Subsequent to making this adjustment the MWRs were put in TIP mode to check on whether the change in set point temperature affected their calibration. Because clear sky conditions were quite intermittent, it is difficult to determine whether the substantial variability in the tip data were attributable to the change in thermal set point. The instrument calibration was not altered in August. Tip data were again collected with these instruments in September prior to the beginning and at the close of the Water Vapor IOP. For example, the calibration of the instrument at the central facility (S/N 10) derived from the September data was essentially the same as that derived from calibration data acquired in February 1996. Although this would lead one to believe that altering the thermal set point did not affect the instrument calibration, it may be that some transient effect was induced. In comparing soundings launched from the central facility with the microwave radiometer there, I noticed that those sondes calibrated in June 1996 consistently reported lower integrated water vapor than the radiometer in July and September (during the IOP) but were in better agreement with the radiometer for the two weeks period immediately after the set point was adjusted. I suspect that adjusting the thermal set point may have temporarily increased the radiometer gain (kelvins/volt) thereby lowering the measured brightness temperature and the retrieved integrated water vapor. It is not clear why a temporary change in gain should occur or even whether it did. But users of the data should be aware that the data from the microwave radiometers at the SGP may be anomalous during August 1996. |
Measurements: | sgpmwrlosB5.a1:
sgp5mwravgC1.c1:
sgp5mwravgB6.c1:
sgpmwrlosB4.a0:
sgpmwrlosB6.a0:
sgpmwrlosC1.b1:
sgpmwrlosB1.a0:
sgp1mwravgC1.c1:
sgpmwrlosC1.a1:
sgpmwrlosB4.a1:
sgpmwrlosB1.a1:
sgp5mwravgB1.c1:
sgp5mwravgB5.c1:
sgpmwrlosB5.a0:
sgp5mwravgB4.c1:
sgpmwrlosB6.a1:
|