DQR ID | Subject | Data Streams Affected |
---|---|---|
D040220.2 | TWP/MWR/C1 - wrong azimuth | twpmwrtipC1.a1 |
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 |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/28/1997 | 0120 | 02/18/2004 | 2250 |
Subject: | TWP/MWR/C1 - wrong azimuth |
DataStreams: | twpmwrtipC1.a1 |
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: | twpmwrtipC1.a1:
|
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:
|