| DQR ID | Subject | Data Streams Affected |
|---|
| D001122.1 | SGP/MWR/C1 - calibration checks | sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D001205.1 | SGP/MWR/C1 - Time drift | sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D010215.5 | SGP/MWR/C1 - IRT failure | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
| D030214.1 | SGP/MWR/B4/C1 - LOS cycle skipping | sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
| D030312.10 | SGP/MWR/C1 - Intermittent Negative Sky Brightness Temperatures | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
| D030822.1 | SGP/MWR/C1 - Incorrect min and max values | sgpmwrlosC1.b1 |
| D030902.1 | SGP/MWR/C1 - no air temperature signal | sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D040824.1 | SGP/MWR/C1 - Wet window flag "on" more frequently than expected | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
| D041001.3 | SGP/MWR/C1 - Instrument problem | sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D041014.1 | SGP/MWR/C1 - thermal instability | sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D041117.2 | SGP/MWR/C1 - Reprocess: wrong retrievals | sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipC1.a1, sgpqmemwrcolC1.c1 |
| D050203.3 | SGP/MWR/C1 - spare instrument | sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D050722.1 | SGP/MWR/C1 - REPROCESS - Revised Retrieval Coefficients | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipC1.a1,
sgpqmemwrcolC1.c1 |
| D050915.1 | SGP/MWR/C1 - Instrument noise problem | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D050919.6 | SGP/MWR/C1 - Instrument offline | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D051011.6 | SGP/MWR/C1 - New software version (4.15) installed | sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D051123.1 | SGP/MWR/C1 - computer problem | sgpmwrC1.00, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D051207.3 | SGP/MWR/C1 - Power supply failure | sgpmwrC1.00, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D060717.2 | SGP/MWR/C1 - Spikes in ambient temperature readings | sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D060821.3 | SGP/MWR/C1 - Missing data | sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D061213.4 | SGP/MWR/C1 - Instrument testing | sgpmwrC1.00, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D070314.2 | SGP/MWR/C1/E14 - Freezing rain-Incorrect rain flag | sgpmwrlosC1.b1, sgpmwrlosE14.b1, sgpmwrtipC1.a1, sgpmwrtipE14.a1 |
| D070802.3 | SGP/MWR/C1 - Noisy data | sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D071128.2 | SGP/MWR/C1 - Reprocess: Radiometer reinstalled- Please reprocess | sgp5mwravgC1.c1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| D080103.2 | SGP/MWR/C1 - Missing data | sgpmwrlosC1.b1 |
| D080625.1 | SGP/MWR/C1 - Missing data | sgp5mwravgC1.c1, sgpmwrlosC1.b1, sgpmwrtipC1.a1 |
| Subject: | SGP/MWR/B4/C1 - LOS cycle skipping |
| DataStreams: | sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrlosC1.a1, sgpmwrlosC1.b1
|
| Description: | When MWR software version 4.12 was installed at the SGP, it was observed
that the MWRs at CF and BF4 skip line-of-sight (LOS) observing cycles. In LOS mode, the
software begins an observing cycle at 0, 20, and 40 seconds after the minute to provide 3
LOS cycles per minute. If a cycle is delayed so that it takes more than 20 seconds to
complete, then the next start time is missed, the cycle is skipped, and the data that would
have been acquired are lost.
It was demonstrated that the interaction with the IRT at CF slowed the MWR observing cycle
noticeably and contributed significantly to the LOS cycle skipping. The IRT was removed
from the MWR on 5 November 2002 and the LOS cycle skipping at the CF was resolved. The
IRT data are now available in a new separate datastream: sgpirtC1.a1 (and soon
sgpirt2sC1.a1).
The BF4 cycle skipping may have resulted from a combination of an additional air
temperature sensor on this instrument and the use of a fiber optic cable. However, the cycle
skipping on this instrument appears to have abated without modifications to the instrument
configuration. |
| Measurements: | sgpmwrlosB4.b1: - Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
- Temperature correction coefficient at 23.8 GHz(tc23)
- Temperature correction coefficient at 31.4 GHz(tc31)
- 31.4 GHz blac2body+noise injection signal(bbn31)
- Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
- Blackbody kinetic temperature(tkbb)
- Sky brightness temperature at 23.8 GHz(tbsky23)
- MWR column precipitable water vapor(vap)
- 31.4 GHz sky signal(sky31)
- Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
- 23.8 GHz Blackbody signal(bb23)
- Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
- Mixer kinetic (physical) temperature(tkxc)
- Averaged total liquid water along LOS path(liq)
- 23.8 GHz blackbody+noise injection signal(bbn23)
- Sky Infra-Red Temperature(sky_ir_temp)
- 31.4 GHz blackbody(bb31)
- Ambient temperature(tkair)
- (tknd)
- 23.8 GHz sky signal(sky23)
- Sky brightness temperature at 31.4 GHz(tbsky31)
- Water on Teflon window (1=WET, 0=DRY)(wet_window)
sgpmwrlosC1.b1: - 31.4 GHz sky signal(sky31)
- Water on Teflon window (1=WET, 0=DRY)(wet_window)
- 31.4 GHz blac2body+noise injection signal(bbn31)
- Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
- 23.8 GHz sky signal(sky23)
- Sky brightness temperature at 31.4 GHz(tbsky31)
- Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
- Averaged total liquid water along LOS path(liq)
- Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
- 31.4 GHz blackbody(bb31)
- Temperature correction coefficient at 31.4 GHz(tc31)
- Blackbody kinetic temperature(tkbb)
- Sky Infra-Red Temperature(sky_ir_temp)
- MWR column precipitable water vapor(vap)
- Ambient temperature(tkair)
- 23.8 GHz Blackbody signal(bb23)
- Sky brightness temperature at 23.8 GHz(tbsky23)
- Mixer kinetic (physical) temperature(tkxc)
- Time offset of tweaks from base_time(time_offset)
- (tknd)
- Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
- 23.8 GHz blackbody+noise injection signal(bbn23)
- Temperature correction coefficient at 23.8 GHz(tc23)
sgpmwrlosC1.a1: - 31.4 GHz blac2body+noise injection signal(bbn31)
- Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
- Sky brightness temperature at 31.4 GHz(tbsky31)
- 23.8 GHz sky signal(sky23)
- Temperature correction coefficient at 23.8 GHz(tc23)
- MWR column precipitable water vapor(vap)
- Sky brightness temperature at 23.8 GHz(tbsky23)
- (tknd)
- Ambient temperature(tkair)
- Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
- 23.8 GHz Blackbody signal(bb23)
- Mixer kinetic (physical) temperature(tkxc)
- Water on Teflon window (1=WET, 0=DRY)(wet_window)
- 31.4 GHz sky signal(sky31)
- Temperature correction coefficient at 31.4 GHz(tc31)
- 31.4 GHz blackbody(bb31)
- Blackbody kinetic temperature(tkbb)
- Sky Infra-Red Temperature(sky_ir_temp)
- Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
- Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
- Averaged total liquid water along LOS path(liq)
- 23.8 GHz blackbody+noise injection signal(bbn23)
sgpmwrlosB4.a1: - Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
- Ambient temperature(tkair)
- 31.4 GHz sky signal(sky31)
- Averaged total liquid water along LOS path(liq)
- 31.4 GHz blackbody(bb31)
- Sky brightness temperature at 31.4 GHz(tbsky31)
- Temperature correction coefficient at 23.8 GHz(tc23)
- (tknd)
- 23.8 GHz Blackbody signal(bb23)
- Sky brightness temperature at 23.8 GHz(tbsky23)
- 23.8 GHz blackbody+noise injection signal(bbn23)
- 31.4 GHz blac2body+noise injection signal(bbn31)
- Mixer kinetic (physical) temperature(tkxc)
- Temperature correction coefficient at 31.4 GHz(tc31)
- Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
- Water on Teflon window (1=WET, 0=DRY)(wet_window)
- Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
- Blackbody kinetic temperature(tkbb)
- Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
- 23.8 GHz sky signal(sky23)
- MWR column precipitable water vapor(vap)
- Sky Infra-Red Temperature(sky_ir_temp)
|
| Subject: | SGP/MWR/C1 - REPROCESS - Revised Retrieval Coefficients |
| DataStreams: | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipC1.a1,
sgpqmemwrcolC1.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 as follows (BCR 456):
SGP/C1 (Lamont) 4/16/2002, 2000
SGP/B1 (Hillsboro) 4/12/2002, 1600
SGP/B4 (Vici) 4/15/2002, 2300
SGP/B5 (Morris) 4/15/2002, 2300
SGP/B6 (Purcell) 4/16/2002, 2200
SGP/E14(Lamont) 4/16/2002, 0000
NSA/C1 (Barrow) 4/25/2002, 1900
NSA/C2 (Atqasuk) 4/18/2002, 1700
TWP/C1 (Manus) 5/04/2002, 0200
TWP/C2 (Nauru) 4/27/2002, 0600
TWP/C3 (Darwin) inception
The MONORTM-based retrieval coefficients became active as follows (BCR 984):
SGP/C1 (Lamont) 6/28/2005, 2300
SGP/B1 (Hillsboro) 6/24/2005, 2100
SGP/B4 (Vici) 6/24/2005, 2100
SGP/B5 (Morris) 6/24/2005, 2100
SGP/B6 (Purcell) 6/24/2005, 1942
SGP/E14(Lamont) 6/28/2005, 2300
NSA/C1 (Barrow) 6/29/2005, 0000
NSA/C2 (Atqasuk) 6/29/2005, 0000
TWP/C1 (Manus) 6/30/2005, 2100
TWP/C2 (Nauru) 6/30/2005, 2100
TWP/C3 (Darwin) 6/30/2005, 2100
PYE/M1 (Pt. Reyes) 4/08/2005, 1900**
** At Pt. Reyes, the original retrieval coefficients implemented in March 2005 were based
on a version of the Rosenkranz model that had been modified to use the HITRAN half-width
at 22 GHz and to be consistent with the water vapor continuum in MONORTM. These
retrievals yield nearly identical results to the MONORTM retrievals. Therefore the Pt. Reyes
data prior to 4/08/2005 may not require reprocessing. |
| Measurements: | sgpmwrtipC1.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)
sgp5mwravgC1.c1: - MWR column precipitable water vapor(vap)
- Averaged total liquid water along LOS path(liq)
sgpmwrlosC1.b1: - MWR column precipitable water vapor(vap)
- Averaged total liquid water along LOS path(liq)
sgp1mwravgC1.c1: - Averaged total liquid water along LOS path(liq)
- MWR column precipitable water vapor(vap)
sgpqmemwrcolC1.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)
sgpmwrlosC1.a1: - Averaged total liquid water along LOS path(liq)
- MWR column precipitable water vapor(vap)
|