| DQR ID | Subject | Data Streams Affected |
|---|
| D010504.2 | NSA/MWR/C2 - Missing data | nsamwrlosC2.b1, nsamwrtipC2.a1 |
| D030515.3 | NSA/MWR/C1 - no air temperature signal | nsamwrC1.00, nsamwrlosC1.b1, nsamwrtipC1.a1 |
| D050203.1 | NSA/MWR/C1 - poor air temperature values | nsamwrlosC1.b1, nsamwrtipC1.a1 |
| D050725.7 | NSA/MWR/C1 - Reprocess: Revised Calibration Coefficients | nsa5mwravgC1.c1, nsamwrlosC1.a1, nsamwrlosC1.b1, nsamwrtipC1.a1, nsaqmemwrcolC1.c1 |
| D050725.8 | NSA/MWR/C2 - Reprocessed: Revised Retrieval Coefficients | nsamwrlosC2.b1, nsamwrtipC2.a1 |
| D050809.2 | NSA/MWR/C1 - Possible loss of accuracy due to missing blower | nsamwrlosC1.b1, nsamwrtipC1.a1 |
| D050830.1 | NSA/MWR/C2 - Thermally unstable | nsamwrlosC2.b1, nsamwrtipC2.a1 |
| D050919.5 | NSA/MWR/C1 - Missing Data | nsa5mwravgC1.c1, nsamwrC1.00, nsamwrlosC1.b1, nsamwrtipC1.a1 |
| D050920.2 | NSA/MWR/C1 - Instrument problem, Heater problem | nsamwrC1.00, nsamwrlosC1.b1 |
| D050928.3 | NSA/MWR/C1 - New software version (4.15) installed | nsamwrlosC1.b1, nsamwrtipC1.a1 |
| D050928.4 | NSA/MWR/C2 - New software version (4.15) installed | nsamwrlosC2.b1, nsamwrtipC2.a1 |
| D050930.1 | NSA/MWR/C1 - Reprocess: wrong calibration | nsamwrlosC1.a1, nsamwrlosC1.b1, nsamwrtipC1.a1 |
| D051020.1 | NSA/MWR/C1 - Incorrect time stamp | nsamwrC1.00, nsamwrlosC1.b1 |
| 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: - MWR column precipitable water vapor(vap)
- Averaged total liquid water along LOS path(liq)
nsa5mwravgC1.c1: - MWR column precipitable water vapor(vap)
- Averaged total liquid water along LOS path(liq)
nsaqmemwrcolC1.c1: - Ensemble average for MWR vapor in window centered about balloon release(mean_vap_mwr)
- Ensemble average for MWR liquid in window centered about balloon release(mean_liq_mwr)
nsamwrlosC1.b1: - MWR column precipitable water vapor(vap)
- Averaged total liquid water along LOS path(liq)
nsamwrtipC1.a1: - Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
- Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
|
| Subject: | NSA/MWR/C2 - Reprocessed: Revised Retrieval Coefficients |
| DataStreams: | nsamwrlosC2.b1, nsamwrtipC2.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 water 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 NSA.C2
20020418.1700. The MONORTM-based retrieval coefficients became active
at NSA.C2 20050629.0000.
Note: The NSA.C2 MWRLOS data for 19991018-20050630 have been reprocessed
to apply the MONORTM-based retrievals for all time. The reprocessed data
were archived in March 2007. The TIP data have not been reprocessed. |
| Measurements: | nsamwrlosC2.b1: - Averaged total liquid water along LOS path(liq)
- MWR column precipitable water vapor(vap)
nsamwrtipC2.a1: - Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
- Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
|
| Subject: | NSA/MWR/C1 - Reprocess: wrong calibration |
| DataStreams: | nsamwrlosC1.a1, nsamwrlosC1.b1, nsamwrtipC1.a1
|
| Description: | When MWR#20 was returned to service on 9/1/2005, the calibration had changed as a result
of the repairs made by Radiometrics and the RF deck temperature had been set to 325K for
testing. On 9/2, the temperature was decreased to 307K to prevent thermal instability in
winter and the calibration was changed in the configuration file with the values supplied
on the repair report.
The data need to be reprocessed with the calibration coefficients that were automatically
derived after these changes were put into affect. They are: tnd_nom23=185.621,
tnd_nom31=158.801, tc23=-0.022, tc31=-0.039. |
| Measurements: | nsamwrlosC1.a1: - MWR column precipitable water vapor(vap)
- Mean 31.4 GHz sky brightness temperature(tbsky31)
- Averaged total liquid water along LOS path(liq)
- Mean 23.8 GHz sky brightness temperature(tbsky23)
nsamwrlosC1.b1: - Mean 23.8 GHz sky brightness temperature(tbsky23)
- MWR column precipitable water vapor(vap)
- Averaged total liquid water along LOS path(liq)
- Mean 31.4 GHz sky brightness temperature(tbsky31)
nsamwrtipC1.a1: - 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
- 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
- Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
- Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
|