| DQR ID | Subject | Data Streams Affected |
|---|---|---|
| D010201.1 | NSA/MWR/C1 - Temperature Stabilization of Noise Diode Impaired | nsa5mwravgC1.c1, nsamwrlosC1.a1, nsamwrlosC1.b1 |
| D050725.7 | NSA/MWR/C1 - Reprocess: Revised Calibration Coefficients | nsa5mwravgC1.c1, nsamwrlosC1.a1, nsamwrlosC1.b1, nsamwrtipC1.a1, nsaqmemwrcolC1.c1 |
| D050919.5 | NSA/MWR/C1 - Missing Data | nsa5mwravgC1.c1, nsamwrC1.00, nsamwrlosC1.b1, nsamwrtipC1.a1 |
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 01/17/2001 | 0600 | 01/22/2001 | 2145 |
| Subject: | NSA/MWR/C1 - Temperature Stabilization of Noise Diode Impaired |
| DataStreams: | nsa5mwravgC1.c1, nsamwrlosC1.a1, nsamwrlosC1.b1 |
| Description: | On 1/17 we had a big spike in the data and lost temperature stabilization. The instrument had problems maintaining the Noise Diode (ND) temperature since. At ambient temperatures under about -20 C the ND was not maintaining the set temperature of 30 C. This problem was reported in P010122.1. Fred Solheim recommended on 1/22 that we powercycle the instrument as it looked like the instrument CPU had lost the temperature reference. So we powercycled the instrument on 1/22 @ 20:30 and lost all comumnication to it; after a second powercycling the instrument came back on line and the temperature stabilized quickly (within a couple of minutes) to the set temperature (30 C) Fred Solheim reported after the system was restored: "I've never seen this behavior before. I don't think it was due to the RF deck physically hanging temperature, because the recorded temp dropped about 30 C in one observation cycle. If this happens again, send the MWR down along with data files for us to look at." Data collected in the periode 1/17/2001 6:00 to 1/22/2001 21:45 are questionable since it is uncertain whether the temperature really was unstable and what really caused the problem. |
| Measurements: | nsamwrlosC1.a1:
nsa5mwravgC1.c1:
nsamwrlosC1.b1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 04/25/2002 | 1900 | 06/29/2005 | 0000 |
| Subject: | NSA/MWR/C1 - Reprocess: Revised Calibration Coefficients |
| DataStreams: | nsa5mwravgC1.c1, nsamwrlosC1.a1, nsamwrlosC1.b1, nsamwrtipC1.a1, nsaqmemwrcolC1.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 NSA.C1 20020425.1900. The MONORTM-based retrieval coefficients became active at NSA.C1 20050629.0000. 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: | nsamwrlosC1.a1:
nsa5mwravgC1.c1:
nsaqmemwrcolC1.c1:
nsamwrlosC1.b1:
nsamwrtipC1.a1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 08/05/2005 | 1952 | 09/01/2005 | 1945 |
| Subject: | NSA/MWR/C1 - Missing Data |
| DataStreams: | nsa5mwravgC1.c1, nsamwrC1.00, nsamwrlosC1.b1, nsamwrtipC1.a1 |
| Description: | Instrument was removed for repair. |
| Measurements: | nsa5mwravgC1.c1:
nsamwrC1.00:
nsamwrlosC1.b1:
nsamwrtipC1.a1:
|