| DQR ID | Subject | Data Streams Affected |
|---|---|---|
| D000717.1 | TWP/MWR/C1 - Rain on window | twpmwrlosC1.b1, twpmwrtipC1.a1 |
| D030312.9 | TWP/MWR/C1 - Intermittent Negative Sky Brightness Temperatures | twpmwrlosC1.b1 |
| D040220.1 | TWP/MWR/C1 - wrong azimuth | twpmwrlosC1.b1 |
| D050725.9 | TWP/MWR/C1 - Reprocessed: Revised Retrieval Coefficients | twp5mwravgC1.c1, twpmwrlosC1.b1, twpmwrtipC1.a1 |
| D050928.1 | TWP/MWR/C1 - New software version (4.15) installed | twpmwrlosC1.b1, twpmwrtipC1.a1 |
| D060420.6 | TWP/MWR/C1 - Software Change | twpmwrlosC1.b1 |
| D060420.9 | TWP/MWR/C1 - software upgrade (version 3.29) | twpmwrlosC1.b1 |
| D061114.2 | TWP/MWR/C1 - Radiometer failure | twpmwrC1.00, twpmwrlosC1.b1, twpmwrtipC1.a1 |
| D070105.1 | TWP/MWR/C1 - Missing data | twpmwrlosC1.b1 |
| D070412.3 | TWP/MWR/C1/C2 - Sun in the field of view | twpmwrlosC1.b1, twpmwrlosC2.b1, twpmwrtipC1.a1, twpmwrtipC2.a1 |
| D070613.1 | TWP/MWR/C1 - Intermittent data | twpmwrlosC1.b1, twpmwrtipC1.a1 |
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 09/25/1997 | 0000 | 11/13/1997 | 0000 |
| 12/01/1997 | 0000 | 01/13/1998 | 0000 |
| 04/01/1998 | 0000 | 03/31/1999 | 0000 |
| Subject: | TWP/MWR/C1 - Rain on window |
| DataStreams: | twpmwrlosC1.b1, twpmwrtipC1.a1 |
| Description: | The data is subject to contamination due to rain on the sensor window and should be used with caution because the heater/blower assembly that prevents water from accumulating on the sensor's teflon window was out of commission. |
| Measurements: | twpmwrlosC1.b1:
twpmwrtipC1.a1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 01/04/2002 | 2200 | 10/31/2002 | 2220 |
| Subject: | TWP/MWR/C1 - Intermittent Negative Sky Brightness Temperatures |
| DataStreams: | twpmwrlosC1.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. |
| Measurements: | twpmwrlosC1.b1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 10/11/1996 | 0000 | 02/18/2004 | 2250 |
| Subject: | TWP/MWR/C1 - wrong azimuth |
| DataStreams: | twpmwrlosC1.b1 |
| Description: | The MWR was initially installed at an azimuth angle defined as 180 degrees but the value in the configuration file was not changed from the default of 0 degrees. In examining photos taken during the installation of the AWS tower, I noticed that the MWR was rotated opposite the normal orientation. The value in the configuration file was changed to reflect the actual azimuth of the instrument. |
| Measurements: | twpmwrlosC1.b1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 05/04/2002 | 0200 | 06/30/2005 | 2100 |
| Subject: | TWP/MWR/C1 - Reprocessed: Revised Retrieval Coefficients |
| DataStreams: | twp5mwravgC1.c1, twpmwrlosC1.b1, twpmwrtipC1.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). The Rosenkranz-based retrieval coefficients became active at TWP.C1 20020504.0200. The MONORTM-based retrieval coefficients became active at TWP.C1 20050630.2100. Note: The TWP.C1 data for 19961011-20050630 have been reprocessed to apply the |
| Measurements: | twpmwrlosC1.b1:
twp5mwravgC1.c1:
twpmwrtipC1.a1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 10/31/2002 | 2200 | 09/13/2005 | 1854 |
| Subject: | TWP/MWR/C1 - New software version (4.15) installed |
| DataStreams: | twpmwrlosC1.b1, twpmwrtipC1.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 9/13/2005. As a consequence of this upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s. |
| Measurements: | twpmwrlosC1.b1:
twpmwrtipC1.a1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 10/11/1996 | 0000 | 02/27/1999 | 1200 |
| Subject: | TWP/MWR/C1 - Software Change |
| DataStreams: | twpmwrlosC1.b1 |
| Description: | The MWR operating software was changed on 27 February 1999 to provide additional functionality as described below. NEW FEATURES 1. Faster sampling rate Standard line-of-sight (LOS) observations can now be acquired at 15-second intervals vs. 20-second intervals previously. (The standard LOS cycle is comprised of one sky sample per blackbody sample and gain update.) 2. More flexible sampling strategy Multiple sky observations can be acquired during a LOS cycle, up to 1024 per gain update. This permits sky samples to be acquired at intervals of 2.67 seconds for improved temporal resolution of cloud liquid water variations and better coordination with the millimeter cloud radar during IOPs. 3. Separation of zenith LOS observations from TIP data When the radiometer is in TIP mode, the zenith LOS observations are now extracted, the PWV and LWP computed and reported separately in the output file. This eliminates the periods of missing LOS data during calibration checks/updates. 4. Automatic self-calibration The software now permits the calibration to be updated at specified intervals or continuously. In the first case, LOS mode is automatically changed to TIP mode at user-specified intervals or whenever clear sky conditions occur, the tip data reduced, the calibration updated, and the radiometer returned to LOS mode without operator intervention. In the second case, the radiometer is continuously is TIP mode until changed by the operator. 5. Graphical user display The graphical display is comprised of a status display, a message display, a temperature plot, a plot of the retrieved PWV and LWP, and (in TIP mode) a plot of the latest tip curves. |
| Measurements: | twpmwrlosC1.b1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 10/11/1996 | 0000 | 03/15/1999 | 1700 |
| Subject: | TWP/MWR/C1 - software upgrade (version 3.29) |
| DataStreams: | twpmwrlosC1.b1 |
| Description: | The MWR operating program was upgraded to version 3.29 on 15 March 1999. This version included a beam width correction as well as provided the capability to automatically level the elevation mirror (that is, to automatically detect and correct offsets in the elevation angle stepper motor position.) The improvement in the quality of the tip curves resulting from the auto-leveling has been dramatic: differences in the brightness temperatures at 3 airmasses (19.5 and 160.5 degrees) have been reduced from +/- 5 K to +/- 0.5 K. In order to take full advantage of this improvement to detect and reject cloudy tip curves, the minimum value of the goodness-of-fit coefficient for a valid tip curve has been increased from 0.995 to 0.998. |
| Measurements: | twpmwrlosC1.b1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 10/09/2006 | 1000 | 01/30/2007 | 0457 |
| Subject: | TWP/MWR/C1 - Radiometer failure |
| DataStreams: | twpmwrC1.00, twpmwrlosC1.b1, twpmwrtipC1.a1 |
| Description: | The instrument stopped responding and had to be powered off. Suspect cause of failure is a faulty digital board. |
| Measurements: | twpmwrC1.00:
twpmwrlosC1.b1:
twpmwrtipC1.a1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 12/09/1996 | 2338 | 12/11/1996 | 0003 |
| 02/28/1997 | 0118 | 06/27/1997 | 2048 |
| 11/06/1997 | 1959 | 11/12/1997 | 1800 |
| 01/05/1998 | 0204 | 01/08/1998 | 2048 |
| 04/21/1998 | 0017 | 04/29/1998 | 1803 |
| 09/13/1998 | 0759 | 09/20/1998 | 0900 |
| 11/20/1998 | 2226 | 11/27/1998 | 1026 |
| 02/27/1999 | 0600 | 03/02/1999 | 0159 |
| 03/06/1999 | 0800 | 03/09/1999 | 1807 |
| 09/03/1999 | 0300 | 09/10/1999 | 0400 |
| 10/01/1999 | 0900 | 10/18/1999 | 0000 |
| 10/20/1999 | 0500 | 10/22/1999 | 0600 |
| 01/14/2000 | 0800 | 01/16/2000 | 0342 |
| 01/14/2006 | 1258 | 01/16/2006 | 0638 |
| Subject: | TWP/MWR/C1 - Missing data |
| DataStreams: | twpmwrlosC1.b1 |
| Description: | Data are missing and unrecoverable. |
| Measurements: | twpmwrlosC1.b1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 03/07/2007 | 0000 | 04/02/2007 | 2359 |
| Subject: | TWP/MWR/C1/C2 - Sun in the field of view |
| DataStreams: | twpmwrlosC1.b1, twpmwrlosC2.b1, twpmwrtipC1.a1, twpmwrtipC2.a1 |
| Description: | Every day between 3/7 and 4/2 around noon local time there is an increase in the brightness temperatures due to the sun in the field of vie of the radiometer. |
| Measurements: | twpmwrlosC2.b1:
twpmwrlosC1.b1:
twpmwrtipC1.a1:
twpmwrtipC2.a1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 06/12/2007 | 0700 | 06/13/2007 | 2000 |
| 06/16/2007 | 2100 | 06/17/2007 | 2100 |
| Subject: | TWP/MWR/C1 - Intermittent data |
| DataStreams: | twpmwrlosC1.b1, twpmwrtipC1.a1 |
| Description: | After a computer change the MWR program did not restart properly. Data are intermittent between 6/12 and 6/17. |
| Measurements: | twpmwrlosC1.b1:
twpmwrtipC1.a1:
|