| DQR ID | Subject | Data Streams Affected |
|---|---|---|
| D001115.1 | SGP/MWR/B1 - occasional negative brightness temperatures | sgpmwrlosB1.00, sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrtipB1.00, sgpmwrtipB1.a1 |
| D010208.4 | SGP/MWR/B1 - noisy data | sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrtipB1.a1 |
| D050725.2 | SGP/MWR/B1 - Reprocess: Revised Retrieval Coefficients | sgp5mwravgB1.c1, sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrtipB1.a1, sgpqmemwrcolB1.c1 |
| D990916.1 | SGP/MWR/B1/B4/B5/B6 - data file split at 23:59 | sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrlosB5.a1, sgpmwrlosB5.b1, sgpmwrlosB6.a1, sgpmwrlosB6.b1, sgpmwrtipB1.a1, sgpmwrtipB4.a1, sgpmwrtipB5.a1, sgpmwrtipB6.a1 |
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 02/27/2000 | 0000 | 06/07/2000 | 2359 |
| Subject: | SGP/MWR/B1 - occasional negative brightness temperatures |
| DataStreams: | sgpmwrlosB1.00, sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrtipB1.00, sgpmwrtipB1.a1 |
| Description: | Occasional spikes in the MWR data were observed. Inspection of the data indicates that these are due to spikes in the gain that result from either unrealistically low values of the blackbody target temperature (~150 K) or unrealistically low values of the microwave signal counts when viewing the blackbody target. Unrealistically low values of the mixer temperature have also been observed. |
| Measurements: | sgpmwrlosB1.00:
sgpmwrlosB1.a1:
sgpmwrlosB1.b1:
sgpmwrtipB1.00:
sgpmwrtipB1.a1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 11/24/2000 | 0000 | 01/30/2001 | 2050 |
| Subject: | SGP/MWR/B1 - noisy data |
| DataStreams: | sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrtipB1.a1 |
| Description: | The MWR exhibited occasional negative sky brightness temperatures that were resolved, after eliminating the instrument and communication lines as the source of the problem, by reformatting and reconfiguring the laptop computer. |
| Measurements: | sgpmwrlosB1.a1:
sgpmwrtipB1.a1:
sgpmwrlosB1.b1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 04/12/2002 | 1600 | 06/24/2005 | 2100 |
| Subject: | SGP/MWR/B1 - Reprocess: Revised Retrieval Coefficients |
| DataStreams: | sgp5mwravgB1.c1, sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrtipB1.a1, sgpqmemwrcolB1.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.B1 20020412.1600. The MONORTM-based retrieval coefficients became active at SGP.B1 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: | sgpmwrlosB1.a1:
sgpmwrlosB1.b1:
sgp5mwravgB1.c1:
sgpmwrtipB1.a1:
sgpqmemwrcolB1.c1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 10/29/1998 | 0000 | 08/12/1999 | 2359 |
| Subject: | SGP/MWR/B1/B4/B5/B6 - data file split at 23:59 |
| DataStreams: | sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrlosB5.a1, sgpmwrlosB5.b1, sgpmwrlosB6.a1, sgpmwrlosB6.b1, sgpmwrtipB1.a1, sgpmwrtipB4.a1, sgpmwrtipB5.a1, sgpmwrtipB6.a1 |
| Description: | A problem with the MWR operating software has been corrected. However, several files were generated that contain one record of data collected at midnight but labeled with the previous day's date. |
| Measurements: | sgpmwrlosB5.a1:
sgpmwrlosB1.a1:
sgpmwrtipB6.a1:
sgpmwrlosB6.b1:
sgpmwrlosB4.b1:
sgpmwrtipB4.a1:
sgpmwrtipB5.a1:
sgpmwrlosB1.b1:
sgpmwrtipB1.a1:
sgpmwrlosB4.a1:
sgpmwrlosB5.b1:
sgpmwrlosB6.a1:
|