| DQR ID | Subject | Data Streams Affected |
|---|---|---|
| D050725.11 | TWP/MWR/C3 - Reprocess - Revised Retrieval Coefficients | twpmwrlosC3.a1, twpmwrlosC3.b1, twpmwrtipC3.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 |
| 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 |
|---|---|---|---|
| 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:
|